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HAND FUNCTION IN THE CHILD: FOUNDATIONS FOR REMEDIATION Copyright © 2006,1995 by Mosby Inc.
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CONTRIBUTORS Dorit Haenosh Aaron, MA, OTR, CHT, FAOTA Coordinator Hand Therapy Fellowship Department of Occupational Therapy Texas Women’s University Houston, Texas Mary Benbow, MS, OTR Private Consultant and Lecturer La Jolla, California Jane Case-Smith, EdD, OTR/L, FAOTA Professor Division of Occupational Therapy The Ohio State University School of Allied Medical Professions Columbus, Ohio Sharon A. Cermak, EdD, OTR/L, FAOTA Professor of Occupational Therapy Department of Rehabilitation Sciences Boston University, Sargent College; Director of Occupational Therapy Training Leadership and Education in Neurodevelopment Disabilities Children’s Hospital and University of Massachusetts Medical Center Boston, Massachusetts Ann-Christin Eliasson, PhD, OT Associate Professor Neuropsychiatric Research Unit Institution of Woman and Child Health Karolinska Institute Stockholm, Sweden
Charlotte E. Exner, PhD, OTR/L, FAOTA Professor Department of Occupational Therapy and Occupational Science Dean College of Health Professions Towson University Towson, Maryland Kimberly Brace Granhaug, OTR, CHT Clinical Manager Sports Medicine and Rehabilitation Christus St. Catherine Katy, Texas Anne Henderson, PhD, OTR Professor Emeritus Department of Occupational Therapy Boston University/Sargent College of Allied Health Professions Boston, Massachusetts Elke H. Kraus, PhD, BSc.Occ.Ther., Dip.Ad.Ed Professor of Occupational Therapy Alice-Saloman University of Applied Sciences Berlin, Germany Carol Anne Myers, MS, OTR/L Occupational Therapist Early Childhood Education Program Newton Public Schools Newton, Massachusetts Charlane Pehoski, ScD, OTR/L, FAOTA Consultant Eunice Kennedy Shriver Center University of Massachusetts Medical School Waltham, Massachusetts
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Ashwini K. Rao, EdD, OTR Assistant Professor of Clinical Physical Therapy Program in Physical Therapy Department of Rehabilitation Medicine Columbia University New York, New York
Scott D. Tomchek, MS, OTR/L Chief of Occupational Therapy Child Evaluation Center University of Louisville School of Medicine Department of Pediatrics Louisville, Kentucky
Birgit Rösblad, PhD, PT Associate Professor Community Medicine and Rehabilitation, Physiotherapy University of Umeå Umeå, Sweden
Laura K. Vogtle, PhD, OTR/L, ATP Associate Professor Department of Occupational Therapy University of Alabama at Birmingham Birmingham, Alabama
Colleen M. Schneck, ScD, OTR/L, FAOTA Professor and Post Professional Program Graduate Coordinator Department of Occupational Therapy Eastern Kentucky University Richmond, Kentucky James W. Strickland, MD Clinical Professor Indiana University School of Medicine Indianapolis, Indiana
Margaret Wallen, MA, OT Senior Occupational Therapist – Research Department of Occupational Therapy The Children’s Hospital at Westmead Westmead, New South Wales, Australia Jenny Ziviani, BAppScOT, BA, MEd, PhD Associate Professor School of Health and Rehabilitation Science The University of Queensland Queensland, Australia
PREFACE TO THE SECOND EDITION The everyday occupations that most of us engage in involve extensive use of our hands. As we perform these occupations we give little thought to the enormous variety of actions our hands can do. A hand can be a platform, a vise, or a hook. It can push and poke, pull and twist, scratch or rub. It can hold a football, an apple, or a raisin. It is the enabler of multiple tool uses. A major task of childhood is the development of this wide variety of hand actions. When a child’s hands are not functioning well or if there is a delay in development, the occupations of childhood are affected, such as playing with objects, dressing, and using tools such as spoons, scissors, or pencils. Remediation of the hand is therefore a major focus of intervention. Hand Function in the Child originally grew out of the recognition that there was a significant gap in the professional literature addressing the problems of hand dysfunction in children, despite the importance of the hand to the child’s development. It has been 10 years since the first edition was published and it still remains the only complete text covering this topic. This second edition again reviews detailed information on the neurological, structural, and developmental foundations of hand function in children. We maintain the focus on the hand as a tool for action and an organ of accomplishment and highlight the complexity of skilled hand use and the long developmental period needed for its perfection. As many of the chapters review information from rapidly changing fields of study, an important purpose of the revised edition was to update these chapters. Another purpose was to add chapters in several areas of content that we felt to be important. The content is presented in three parts. The first part, “Foundation of Hand Skills,” provides information on the anatomical, neurological, physiological, and psychological aspects of hand function. This section begins with an updated chapter on control within the central nervous system that describes the mechanisms that allow skilled use of the hand as it relates to handobject interaction. This is followed by a chapter on the embryology, anatomy, kinesiology, and biomechanics
of the hand. The third chapter explores sensory control and the way in which the control of grasp and lifting of objects varies with differing sizes, shapes, and textures. The next chapter examines the development and evaluation of the ability of infants and children to recognize objects and object properties felt by the hand. The fifth chapter updates the research on the role of vision in the control of movements in the environment, and covers the development of visual control in childhood. The final chapter in Part I is new in this edition and highlights the cognitive processes required for the acquisition and performance of hand skills. Part II, Development of Hand Skills, explores the changes in hand skills that occur with age. The first chapter on the early development of grasp, release, and bimanual activities has been revised to present the content in the context of infant play from birth to 2 years. The second chapter examines object manipulation from birth throughout childhood. Chapter 9, on handedness and its development, is new and includes an extensive review of research on hand preference as well as on the evaluation of hand preference. Chapter 10, on the development of self-care activities in relation to the development of hand skills, contains additional information on current measures and on cultural influences. The final chapter in Part II has a new, extensive review of recent research on handwriting. Therapeutic intervention is presented in Part III. The chapters focus on the overall remediation of hand skills, on the remediation of special problems, and on specific areas of intervention. Chapters 12 and 15 have been updated and revised. The remaining six chapters in this section are new. Chapter 13 presents ideas on how the engage the preschool child in hand activity and to incorporate treatment activities into the classroom. The next chapter reviews problems related to handwriting difficulties and presents formal and informal assessments. Chapters 16, 17, and 18 focus on specific areas of dysfunction and intervention. We chose a review of research on the effectiveness of improving hand function for the final chapter.
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Our primary vision continues to be to present in a single text current information on the neurological foundations of hand skills, the development of hand skills, and intervention for children with problems related to hand skills. We hope that a comprehensive review of the hand will provide an important resource and clinical guide for students, practicing pediatric therapists, and others who work with children.
ACKNOWLEDGMENTS The editors wish first to acknowledge with gratitude the time and expertise donated by the contributors to this volume. These authors are highly regarded in their respective fields, and we thank them for their insights and the wealth of practical and theoretical understanding they bring through their chapters. We hope that the diversity of ideas presented here will enrich the reader’s understanding and appreciation of the immense complexity and the multiple dimensions of the human hand and particularly of its importance to daily living from birth through adolescence. This book is the culmination of the efforts of many people who contributed ideas over an extended period of time. The formal beginnings of the book occurred during a series of workshops for occupational and physical therapists funded by the Maternal and Child
Health Bureau, U.S. Department of Health and Human Services, Department of Public Health. The workshops were sponsored by the Occupational Therapy and Physical Therapy Departments at the University of Illinois at Chicago between 1988 and 1991. Several of the contributors to the first edition participated in yearly task groups on the hand of the child, motivated by the need to share information in a field where so little had previously been written. It was from these meetings that the idea of a comprehensive book on hand skills in children arose. The reception of the first edition by many professional colleagues and their comments helped shape this second edition. We would also like to acknowledge the help and assistance of Kathy Falk, our editor at Elsevier, whose support enhanced all the phases of the production of this book by answering our questions and providing a workable and timely schedule. Thanks also to Sarah Wunderly, our production manager, and other Elsevier staff for assisting in the final phase of our work. Finally we want to recognize the families and children we and our authors have known through our professional practice and research for they have contributed much to our current knowledge of hand function in the child. Anne Henderson Charlane Pehoski
PREFACE TO THE FIRST EDITION …[M]an though the use of his hands, as they are energized by mind and will, can influence the state of his own health. (Reilly, 1962, p.2)
The hand is our primary means of interaction with the physical environment, both though the dexterous grasp and manipulation of objects and as the enabler of multiple tool functions. The enormous variety of actions accomplished by our hands ranges from the practical to the creative. The hand is incredibly versatile. It can be a platform, a hook, or a vise. It can hold a football, a hammer, or a needle. It can explore objects, express emotion, or communicate language. The hand is the subject of this book, most specifically the hand as a tool for action, as an organ of accomplishment. The motor functions of the hand are some of the most complex and advanced of all human motor skills. Hand use is voluntary, under the control of the conscious mind, and is regulated by feedback from sensory organs. The complexity of skilled hand use is shown by the long developmental period needed for its perfection. The ability to manipulate objects with the efficiency and precision of an adult continues to improve throughout late childhood and early adolescence. The plan for this book grew out of the recognition that, although the treatment of hand dysfunction has been a critical area of occupational therapy practice since the beginning of the profession, for many years the professional literature in pediatrics placed a greater emphasis on the neurophysiology and development of gross motor abilities than on manipulative skills. A renewed attention to manipulative abilities, beginning about 15 years ago, was spearheaded by the writings of therapists such as Rhonda Erhart, Reggie Boehm, and Charlotte Exner, and professional literature on the developmental treatment of hand skills has since increased. During a similar period there has been increasing research attention in the fields of neurophysiology and psychology to the motor skills of the hand. Although there are many unresolved issues about hand devel-
opment and dysfunction in childhood, it seemed timely to review that which is currently known. This book is intended for the professional and student interested in the current research and treatment of problems in children’s hand skills. The text is organized around themes from neurobehavior and development, drawing together information that is pertinent to the understanding of dysfunction in the hand in children and as a guidance to intervention. Hand function is reviewed from the perspectives of neurophysiology, neuropsychology, cognitive psychology, developmental psychology, and therapeutic intervention. The text is organized into three sections, each of which presents several dimensions of hand function. Section I includes chapters on the biologic and psychologic foundations of hand function. The first chapter describes the cortical control of skilled hand use and identifies the properties of that control that are different from the control of gross motor skills. The second chapter presents the anatomic structure and function of the hand facilitating the varied functions. Two chapters on the sensory guidance of the hand function follow, one on touch and proprioception and the other on vision. The other two chapters in Section I review knowledge from several branches of psychology, including the perceptual functions of the hand and the role of cognition in hand activity. Section II focuses on development in both general and specific areas of hand skill. Two chapters in this section focus on the development of basic skills. The first reviews research on the development of grasp, release, and bimanual skills in infancy and the second the development of object manipulation. Other chapters cover specific and complex skill areas of graphic skill and self-care and the development of hand dominance.
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Section III provides knowledge from selected pediatric clinical practice areas. Two of the five chapters describe dysfunction and treatment of special populations with cerebral palsy and Down syndrome. Another chapter presents the principles and practice of the remediation of hand skill problems, while a fourth focuses on the specific area of teaching handwriting. The remaining chapter identifies the many toys that are the natural media for the treatment of hand dysfunction in children. Despite the acceleration of research in the last decade, the study of the development of hand use and the treatment of hand dysfunction in children is still in its infancy. It is our hope that assembling this
information on hand skills will stimulate interest in the development of research programs that will increase the body of knowledge about normal and deviant hand skill development and the efficacy of intervention. This text was written primarily for pediatric occupational therapists and could serve as a graduate level text or as a reference book in entry level education. However, we anticipate that it will be of value for anyone working with toddlers and children, including preschool and elementary teachers, special educators, early intervention providers, and other therapists. Anne Henderson Charlane Pehoski
Chapter
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CORTICAL CONTROL OF HAND-OBJECT INTERACTION Charlane Pehoski
CHAPTER OUTLINE MOVING THE FINGERS INDEPENDENTLY: DIRECT CORTICOSPINAL CONNECTIONS TO ALPHA MOTOR NEURONS OF THE HAND AND PRIMARY MOTOR CORTEX Direct Corticospinal Connections to Alpha Motor Neurons of Hand Muscles Primary Motor Cortex Use-Dependent Organization of the Primary Motor Cortex SENSORY GUIDANCE OF HAND MOVEMENTS: PRIMARY SOMATOSENSORY CORTEX Cortical Organization of the Somatosensory System Use-Dependent Organization Within the Primary Somatosensory Cortex Role of Somatosensory Input in Grasp Role of Somatosensory Cortex in Motor Learning THE TRANSFORMATION OF VISUALLY OBSERVED CHARACTERISTICS ABOUT OBJECTS INTO APPROPRIATE HAND CONFIGURATIONS: POSTERIOR PARIETAL LOBE AND VENTRAL PREMOTOR CORTEX Role of the Inferior Parietal Lobe in Preshaping of the Hand Role of the Ventral Premotor Cortex in Preshaping of the Hand Use-Dependent Organization of the Inferior Parietal and Ventral Premotor Cortex The Inferior Parietal Cortex and Tool Use SUMMARY AND THERAPEUTIC IMPLICATIONS
When I first met Katie she was 6 years old and was having a great deal of difficulty managing the fine motor tasks typical of most kindergarten children. She was clumsy and had difficulty with such tasks as buttoning and using tools. Her score on the Peabody Developmental Fine Motor Scales was −2.33 standard deviations below the mean for her age and her age equivalent score was 3 years 6 months. This is not an unusual profile for children referred because of poor fine motor skills. What was unique about Katie was that the source of her difficulty was known. A benign tumor had been removed from her right posterior parietal lobe when she was 3 years old. Many of the difficulties she experienced in hand–object interaction could be attributed to the location of her lesion. For example, she was underresponsive to tactile input and often used excess force when holding objects. When asked to feel forms placed in her hand without looking, she just grasped them and did not explore them with her fingers. She had a great deal of difficulty in tasks that required “in-hand manipulation,” such as moving a small object from the palm of the hand to the fingers. Objects often were dropped. This chapter discusses the posterior parietal lobe and its importance for hand–object interaction. However, this is not the only important area; other cortical regions are also explored. The capacity to use the hand with skill in hand– object interactions represents an evolutionary ability characteristic of the behavior of higher primates. Three fundamental prerequisites are necessary for this function: (a) the capacity for independent control over the fingers, (b) a sophisticated somatosensory system to guide finger movements, and (c) the ability to transform sensory information concerning object properties into appropriate hand configurations (Binkofski et al., 1999). Each of these prerequisites is served by separate
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Part I • Foundation of Hand Skills
but interconnected areas of the cerebral cortex. This includes the primary motor cortex, primary somatosensory cortex, parietal cortex (particularly the area around the intraparietal sulcus), and premotor cortex (particularly the ventral portion). That is not to say that other motor structures, such as the supplementary motor areas, cingulated motor areas, cerebellum, and basal ganglion do not also serve important functions (e.g., Ehrsson, Kuhtz-Buschbeck, & Forssberg, 2002; Lemon, 1999; Schlaug, Knorr & Seitz, 1994), but rather that the cortical regions mentioned previously seem critically related to skilled action of the hand, particularly as it interacts with objects. This chapter reviews each of the mentioned prerequisite skills and the cortical areas important for their functions. The purpose of this chapter is to better understand the problems of children like Katie and provide evidence for the need to encourage skilled hand use in these children.
MOVING THE FINGERS INDEPENDENTLY: DIRECT CORTICOSPINAL CONNECTIONS TO ALPHA MOTOR NEURONS OF THE HAND AND PRIMARY MOTOR CORTEX DIRECT CORTICOSPINAL CONNECTIONS TO ALPHA MOTOR N EURONS OF HAND M USCLES As indicated, one prerequisite for skilled hand use is the control over individual finger movements. This is true even for a seemingly simple task such as picking up an object using a precision grip.1 Try picking up a small object between your index finger and thumb. Pick it up slowly enough so you can observe the action of the fingers. Note the isolation of movement between the index finger and thumb and the movement of the remaining fingers as they get out of the way of the action. If, during this task, your hand muscles had been attached to an electromyograph (EMG) you would have seen that the muscles necessary for this task showed marked variation with respect to the precise timing of their onset and time course of activity during the task, resulting in the specificity of finger move1 This chapter uses the term “precision grip” when referring to the act of picking up a small object between the index finger and thumb because this is the term used in the neurophysiologic research that is reviewed.
ments. This is in contrast to a power grip, in which all the muscles are coactivated (Bennett & Lemon, 1996; Muir, 1985). Even simple finger movements such as this require hand muscles to work in a specific temporal order and with varying amounts of force (DarianSmith, Burman, & Darian-Smith, 1999). This ability to “fractionate,” or move the fingers individually, is thought to result from the special contribution of direct corticospinal connections primarily from neurons in the motor cortex to the alpha motor neuron of hand muscles in the ventral horn in the spinal cord (see Lemon, 1993, for a review). The ventral horn of the spinal cord is divided into two main sections, an interneuron zone and the motor neuronal pool or “final common pathway” to the muscle. The motor neurons in the ventral horn are not randomly distributed but are clustered into cell columns, a medial cell column that contains the motor neurons for the trunk, shoulder girdle, and hips, and a lateral cell column that contains motor neurons for the distal extremities (Kuypers, 1981). Almost all descending motor fibers first terminate in the interneuronal zone, so that there is at least one interneuron between the descending motor fiber and motor neuron. An important exception is the direct corticospinal fibers to alpha motor neurons of the distal extremity (Figure 1-1). This direct path is fast and thought to be important in moving the hand with speed and skill. These special connections also are thought to be preferentially related to the intrinsic hand muscles (Maier et al., 2002). The intrinsic hand muscles provide the ability to handle small objects with precision (Long et al., 1970). Direct corticospinal fibers seem to be a feature unique to
Corticospinal tract Direct corticospinal input Indirect corticospinal input
Interneuron zone
Muscle of distal extremity
Figure 1-1 Termination of the corticospinal tract in the spinal cord. The diagram shows a single fiber that synapses in the interneuronal zone and then makes connections with a muscle through the interneuron. Also shown is a fiber within the corticospinal tract that makes a direct connection to a motor neuron of a distal limb muscle.
Cortical Control of Hand-Object Interaction • 5 primates and are particularly well developed in the most dexterous primate species (Nakajima et al., 2000). Lemon (1993) suggests that the direct corticospinal projections allow motor commands to bypass spinal mechanisms and break up synergies by direct access to the motoneurons and the final common pathway. This allows the flexibility of individual finger movements with wrist actions appropriate to a given task.
PRIMARY MOTOR CORTEX Although a large number of structures are involved in the neural control of the hand, the importance of the primary motor cortex for the execution of independent finger movements is well established (Ehrsson et al., 2002; Huntley & Jones, 1991) (Figure 1-2). Neurons that are the source of the direct corticospinal connections are more numerous in the hand area of the primary motor cortex than connections from other cortical areas, such as the supplementary motor cortex (Lemon et al., 2002; Maier et al., 2002). This area of cortex is particularly well represented in nonhuman primates by the ability to form a precision grip. Damage to the motor cortex results in deficits in fine manual coordination. Monkeys with lesions to this area lose the ability to produce a precision grip and small objects are picked up by the use of a more mass grasp in which all the fingers work together (Fogassi et al., 2001; Rouiller et al., 1998; Schieber & Poliakov, 1998). Difficulty with independent finger movements can also be seen in humans with lesions restricted to the primary motor cortex or the corticospinal tract. Lang and Schieber (2003) found that the fingers of the affected hand in patients with damage to these areas moved less independently than the fingers of the uninvolved extremity or normal controls. This was particularly true for abduction and adduction of the fin-
Primary motor cortex Central sulcus
Figure 1-2
Diagram of the primary motor cortex.
gers. When EMG recordings were made of hand muscles during abduction and adduction movements of the fingers, activation of the first dorsal interosseous of the normal hand was seen only when the person moved the index finger. That is, the muscle’s response was isolated and only related to the movement of this one finger. In the disabled hand, this muscle was active with thumb, index, and ring finger movements. The authors concluded that cerebral areas and descending pathways that are spared in humans may activate finger muscles, but cannot fully compensate for the highly selective control provided by the primary motor cortex. The primary motor cortex has a particular relationship to the hand. The cortical representation of muscles involving the fingers occupies a larger area than those concerned with shoulder movement (Paillard, 1993). Hand muscles may also be more dependent on cortical mechanisms. Turton and Lemon (1999) used transcranial magnetic stimulation (TMS) to look at the effects of stimulation of the primary motor cortex on EMG output of the deltoid, biceps, and first dorsal interosseous muscles when the participants contracted each muscle. (TMS is a noninvasive way to stimulate neurons in the motor cortex using a small coil placed over the appropriate area of the head.) They found that the EMG response to this additional facilitation was significantly greater in the hand muscles than the biceps, which was greater than in the deltoid. That is, the “extra” input provided by the TMS through the primary motor cortex was greatest in the hand muscles. They suggest that this reflects a major difference in the dependence on cortical mechanisms in hand muscles as opposed to more proximal muscles. Therefore the hand seems to have a privileged relationship with the primary motor cortex.
USE-DEPENDENT ORGANIZATION OF THE PRIMARY MOTOR CORTEX One of the significant research findings in the last few years is that the functional organization of the primary motor cortex is dynamic and changes as a result of use. “Use-dependent” changes have been seen in the motor cortex of a wide variety of animals (e.g., Kleim et al., 1996; Remple et al., 2001), including humans (e.g., Classen et al., 1998; Pascual-Leone, Grafman, & Hallett, 1994). What appears to happen is that the representation of the “used” muscles expands or the movements that are used together are represented together (Nudo et al., 1996). There is not one representation of the human hand in the motor cortex; rather, multiple overlapping representations are functionally connected through a horizontal network between motor neurons (Butefisch, 2004; Huntley & Jones, 1991; Sanes & Donoghue, 2000). Dynamically
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changing patterns can be achieved by changing the strength of these horizontal networks through use (Butefisch, 2004). This is a requirement for motor learning. The brain must have the ability to adapt to new and changing circumstances, including both the learning of new skills and recovery from injury (Jackson & Lemon, 2001). An example of a “use-dependent” change was demonstrated by Karni et al. (1998). In this study, typical adults practiced a finger sequence task daily for 5 weeks (opposing the fingers of the nondominant hand to the thumb in a specific order). The participants also were given a second finger sequence that was not practiced and served as a control for the study. Functional magnetic resonance imaging (fMRI) of the cerebral cortex was done at the start of the experiment and then weekly until the end of the experiment. The authors found that in the initial images done before the experiment began there were no differences between the cortical representation of the experimental and control sequences. At 3 weeks, when the experimental sequence had been well learned, the area of motor cortex representing the experimental sequence had become larger. Changes also have been seen using intracortical microstimulation in monkeys, in which the neuronal representative of movements in the distal forelimb area of the primary motor cortex can be specifically mapped. In one study the extent of the representation of the hand was mapped and then the monkeys were trained to pick up small food pellets from a food well (Nudo et al., 1996). After training, intracortical microstimulation of the primary motor cortex was done again and the researchers found that the representation of the movements used in the food retrieval task had expanded. They also looked at the representation of unpracticed wrist and forearm movements, and found that the representation of these movements had contracted. To demonstrate that these changes are reversible and that the primary motor cortex changes are based on use, the monkeys were then trained to perform supination and pronation movements in a key turning task. Intracortical microstimulation demonstrated an expansion of the forelimb area and contraction of the digital representational zones. They also found that movement combinations used in the acquisition of these skilled motor tasks had come to be represented in the same cortical territory. Consequently, use of a particular motor pattern causes structural reorganization in the primary motor cortex. Actions that are practiced come to represent a larger area of cortex and the muscle groups involved also come to be represented together in what appear to be functional groupings (Nudo et al., 1996); however, not all “use” or practice may be as effective in driving these changes. As discussed later, passive movements and
strength training appear to be less effective in driving reorganization of the primary motor cortex. Alternately, skill training or learning may be a particularly powerful force for reorganization. With respect to passive movements, Lotze et al. (2003) used fMRI to look at the effects of 30 minutes of passive versus active wrist movement in typical adults. They found that the accuracy of wrist movements improved more with active movements and that cortical reorganization as measured by fMRI also was greater with active compared with passive movement. In a clever experiment that looked at the effect of strength training, Remple et al. (2001) trained one group of rats to break increasingly larger bundles of pasta with their forelimb and a second group to break single strands of pasta. A control group that had no training in either task also was included in the study. After 30 days of training, the researchers found an increase in the proportion of motor cortex occupied by distal forelimb movements in both experimental groups but not the control group. They concluded that the development of skilled forelimb movements, but not increased forelimb strength, is associated with reorganization of forelimb areas in the primary motor cortex. The need for the animal to be engaged in a skilled task or actually learn a task for significant changes in the primary motor cortex to be observed also has been reported. In two complementary studies, Nudo et al. (1996) and, Plautz, Miliken, and Nudo (2000), the researchers trained monkeys to retrieve food pellets from food wells. In one group, the well was large and therefore the task was fairly easy, so no skill or learning was involved (Plautz et al., 2000) (Figure 1-3). Another group of monkeys was required to use much smaller food wells that required learning to retrieve the food pellet (Nudo et al., 1996). Both groups used the same fingers and were given the same number of pellets to retrieve but only in the group of monkeys in which the task required learning a new skill was there evidence of modification of cortical maps. The authors concluded that, “Repetitive motor activity alone does not produce functional reorganization of cortical maps. Instead we propose that motor skill acquisition or motor learning is a prerequisite factor in driving representational plasticity in the primary motor cortex” (Plautz et al., 2000; p. 27).
Even adult patients who had reached a plateau in their recovery after suffering a stroke showed an increase in function (Taub & Morris, 2001) and expansion of the cortical hand representation (Liepert et al., 2000) after constraint induced movement therapy (noninvolved extremity restrained to force use of the involved extremity).
Cortical Control of Hand-Object Interaction • 7
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Figure 1-3 Depiction of a squirrel monkey performing a large pellet retrieval task. Note the relative simplicity of the task because of the size of the well compared with the size of the animal’s hand. (Redrawn from Plautz E, Miliken G, Nudo R [2000]. Effects of repetitive motor training on movement representation in adult squirrel monkeys: Role of use versus learning, Neurobiology of Learning and Memory, 74:27–55.)
Use can change the organization of the primary motor cortex, but disuse also can have an effect on centers important to motor skills. Using kittens, Martin et al. (2004) demonstrated that restricting the use of one paw for the first 7 weeks after birth created permanent changes both in the skill of that paw and the morphology of the direct corticospinal connections in the spinal cord. In another example, a group of researchers followed adults who had undergone surgical treatment of the flexor tendons of the hand (deJong et al., 2003). For 6 weeks after surgery, the patients were required to wear a dynamic immobilization splint that allowed passive but not active finger flexion. After the splint was removed, the patients complained of a temporary clumsiness of the hand that could not be explained by stiffness of the fingers or adhesions. In one patient, EMG studies were done after splint removal and flexion of the fingers showed increased cocontraction of the extensor muscles and no full relaxation of this muscle was seen between sets of movement. In four patients, positron emission tomography (PET) was used to look at task-related increases in cerebral blood flow as they flexed their fingers. These scans were done immediately after the splint was removed and again 6 to 10 weeks after removal. They found that scans immediately after splint removal demonstrated activation in the posterior parietal lobe and cingulate sulcus. This was not seen in the nonsurgical hand. The authors suggested that the increase in parietal involvement (an area of tactile and visual convergence discussed later in this chapter) may
be related to an increased demand on body scheme representation that is needed for instructing the appropriate parts of the hand to move. The cingulate may represent the recruitment of secondary motor function for the execution of simple hand movements. After the splint had been removed for several weeks, a second scan showed movements related to the putamen, a subcortical structure. The authors indicated that the shift from cortical to subcortical involvement may indicate that movements have been relearned. In summary, hand skill is possible because of the ability to move the finger individually and with speed. This ability is provided by the primary motor cortex and direct corticospinal fibers to hand muscles. The integrity of this cortical motor system is being tested in part when a child is asked to tap his or her index finger and thumb together as rapidly as possible or quickly oppose the individual fingers to the thumb. The speed with which these movements can be performed increases with age (e.g., Denckla, 1974). Evans, Harrison, and Stephens (1990) suggest that there is a relationship between a child’s ability to perform rapid finger movements and maturation of a cutaneomuscular reflex dependent on the corticospinal tract, as well as the main sensory pathway. The results of maturation in this system are demonstrated when an infant of 9 to 10 months begins to use a precision grip to pick up small objects (Siddiqui, 1995). It is apparent that the hand needs to be used, particularly in skilled tasks. This need for use also is seen for other cerebral areas involved in control of the hand, particularly the primary somatosensory cortex, which is discussed next.
SENSORY GUIDANCE OF HAND MOVEMENTS: PRIMARY SOMATOSENSORY CORTEX The hand is both a motor and sensing organ and there is a tight interplay between these two functions. The delicate movements of the hand and fingers are needed to “gather” sensory information, and those delicate movements need sensory feedback to guide action, particularly actions with objects. When objects are handled they do not fall from the fingers, nor does one use excessive force when picking things up. The information needed for these activities is provided by sensory feedback. The importance of this sensory information is obvious when one removes a glove to gather change from a pocket or when performing any delicate activity with the hand. Figure 1-4 shows the attempts of a woman with complete loss of sensation in her right hand trying to crumple a piece of paper (Jeannerod,
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Part I • Foundation of Hand Skills RH
LH
Michel, & Prablanc, 1984). Note the difficulty she has in coordinating the fingers of her right hand. She was reported to be able to reach for objects, eat normally, and write (although with difficulty), all tasks she could control using vision. Activities outside visual control, such as combing hair or buttoning, were problematic, as were activities that require the fingers to work together as in the paper-crumbling task. No detectable motor deficit, such as the ability to perform rapid tapping of the index finger, was noted (i.e., motor functions were intact). A computed tomography (CT) scan found that this woman had a very large lesion involving the somatosensory cortex and superior parietal lobe (Jeannerod, Michel, & Prablanc, 1984). (Note that this woman’s lesion extended beyond the primary sensory cortex and probably contributed to the severity of her disability). Figure 1-5 shows similar disorganization of finger movements in a monkey with a lesion in area 2 of the somatosensory cortex (Hikosaka et al., 1985). Brochier, Boudreau, and Smith (1999) also found a loss of finger coordination and poor positioning of the fingers when grasping objects in monkeys with inactivation of the somatosensory cortex. This section discusses the important roles sensory information plays in skilled hand movements, including the role it plays in motor learning.
CORTICAL ORGANIZATION OF THE SOMATOSENSORY SYSTEM
Figure 1-4 Schematic of a woman with a lesion in the somatosensory cortex and superior parietal lobe attempting to crumble a sheet of paper with her left hand (LH) and involved right hand (RH). (Redrawn from Jeannerod M, Michel M, Prablanc C [1984]. The control of hand movements in a case of hemianaesthesia following a parietal lesion. Brain, 107:899–920.)
The primary receiving area for somatosensory information from the limbs is the area of cortex just behind the central gyrus. This area generally is called the primary somatosensory cortex (Figure 1-6). It is the major termination of the dorsal columns, which carries discrete somatosensory information from the periphery. This major tract has evolved in parallel with the corticospinal tract, and like this system it reaches it highest level of development in humans (Paillard, 1993). Information carried in the dorsal columns can register even small movements of joints and provide knowledge of the exact location of stimulus on the skin. It was designed to provide specific information about what is happening in the periphery. In both monkeys (Sakata & Iwamura, 1978) and humans (Moore et al., 2000) the primary somatosensory cortex is composed of four areas, generally called Brodmann’s areas 3a, 3b, 1, and 2 (see Figure 1-6). An understanding of the function of the primary somatosensory area is helpful to appreciate the complexity of information processing within this area, particularly for the hand. Afferent fibers from the dorsal columns project mainly to area 3b for cutaneous input and area 3a for
Cortical Control of Hand-Object Interaction • 9
IPSI
CONTRA
Figure 1-5 Disruption of finger coordination after inactivation of area 2 in a monkey. The sequence of movements (left to right) shows the animal’s attempts at picking up a piece of apple from a funnel. IPSI indicates the “normal” hand ipsilateral to the inactivated region. CONTRA indicates the disorganized movements of the affected hand contralateral to the inactivated region. (Redrawn from Hikosaka O, Tanaka M, Sakamoto M, Iwamura Y [1985]. Deficits in manipulative behaviors induced by local injection of muscimol in the first somatosensory cortex of the conscious monkey. Brain Research, 325:375–380.)
deep, proprioceptive information (information arising from an activity such as active flexion and extension of the fingers) (Iwamura, 1998; Moore et al., 2000). Area 3b sends information to area 1 and area 1 sends information to area 2. Both areas then send information to the parietal lobe (Inoue et al., 2004). Therefore there is a serial or hierarchical processing of information across this area (Ageranioti-Belanger & Chapman, 1992; Inoue et al., 2004; Iwamura, 1998; Iwamura et al., 1985). One of the transformations in sensory information that is seen as information is processed in more posterior cortical regions is the response of a single neuron to stimulation over wider areas of skin. For example, there is an increase in the number of multidigit receptive fields (the area from which stimulation causes a single cortical neuron to fire) when progressing from area 3b, where 46% of neurons respond to multiple sites; to area 1, where the percentage is 63%; to area 2, where 85% of neurons respond to stimulation from multiple sites (Ageranioti-Belanger & Chapman, 1992). That is, the discrete information that first arises from the periphery appears to be combined into progressively more functionally relevant networks. In a study of neurons in area 2 of monkeys, Iwamura et al. (1985) suggested that this convergence represents skin surfaces that come in contact as the result of com-
mon behaviors of the animal. Like the primary motor cortex, which tends to cluster muscles that have repeatedly worked together in interconnected networks, the same appears to be true of sensory information processed in the primary somatosensory cortex. Also like the motor cortex, the organization of the sensory cortex is dependent on use. Therefore these two areas allow for a great deal of flexibility in how information is organized to best serve a variety of functional activities.
USE-DEPENDENT ORGANIZATION WITHIN THE PRIMARY SOMATOSENSORY CORTEX The primary sensory cortex is dynamic and changing. This has led one researcher to suggest that at any given time the details of the somatosensory cortex organization reflect the behavioral experience of the animal (Recanzone et al., 1992). That is, the sensory representation of the extremities contracts or expands depending on the use or lack of use of a body part. In an interesting study, Scheibel et al. (1990) did a postmortem examination of the dendritic complexity in several areas of the cerebral cortex in 10 individuals. The authors found a great deal of variability in the hand area of the somatosensory cortex of these individuals
10
Part I • Foundation of Hand Skills Central Sulcus
3a
3b 1 2 Primary somatosensory cortex
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Central sulcus 2 1
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Figure 1-6 A. Somatosensory cortex. B. Cross section of somatosensory cortex showing Brodmann’s areas 3a, 3b, 1, and 2.
and felt that at least in some (e.g., former typist, appliance repairman) these differences might be related to the individual’s premorbid occupation. In a more recent study, Hashimoto et al. (2004) used noninvasive techniques to study the somatosensory cortex in string players. They found an enlarged cortical representation of the hand area in these individuals compared with controls who did not play a string instrument. Like the motor cortex, research seems to indicate that skilled learning or attention to a task may be particularly effective in mediating these cortical changes. Using a behavioral task similar to the one used for studying the changes in the motor cortex of monkeys, animals were trained to pick up food pellets placed in wells of varying diameters (Xerri et al., 1999). This included large-diameter wells in which the pellets were easy to retrieve, and smaller-diameter wells in which retrieval was more difficult. The researchers found that sensory neurons responsive to the specific finger surfaces that had been engaged in the small retrieval task showed major representative changes within area 3b of the somatosensory cortex that were not seen with other finger surfaces. That is, changes reflected digital surfaces that were necessary for object retrieval under
difficult task conditions or in which the animal had to learn a skilled task. In another study, Recanzone et al. (1992) trained two groups of monkeys to place their hands on a mold of the hand. The purpose of the mold was to keep the hand in the same position so a vibratory stimulus could be given to a small site on one of the fingers. One group of animals was trained to lift the hand when they perceived changes in the vibratory input. In other words, these monkeys were to attend to and then make an adaptive response to this tactile stimulus. Another group of monkeys also received the vibratory stimulus but were trained to lift the hand to changes in an auditory stimulus. These animals therefore received the vibratory stimulus in a passive manner and were not required to act on the input. When the area in the primary sensory cortex of these animals that represents the stimulated portion of skin was mapped, both experimental animals showed an increase in the representation of this skin area. However, the increase in the animal who had been the passive recipient of the vibratory stimulus was modest. The authors suggest that attention influences cortical reorganization and that stimulation alone is far less effective in driving cortical reorganization than an active response to the stimulus. In other words, being engaged in the activity and making an adaptive response based on sensory input were the most efficient means of driving the cortical changes seen in this study. It also should be mentioned that in humans, Godde, Ehrhardt, and Braun (2003) showed a 20% decrease in two-point thresholds on the tip of the index finger and a change in the cortical map of this finger after 3 hours of intermittent, purely passive tactile stimulation to the fingertip. Apparently passive input also can promote organizational changes in the primary somatosensory cortex along with some modest improvement in tactile discrimination.
ROLE OF SOMATOSENSORY I NPUT IN G RASP Tactile information from the fingers is necessary to adjust the grip to the weight and friction of an object. This is particularly true when picking up a small object in the fingertips. Sensitive tactile receptors in the fingertips are able to sense the “slip” of an object even before this slip comes to conscious attention. Appropriate adjustments in the grip then can be automatically made (Johansson & Westling 1984, 1987; Westling & Johansson, 1984). If the friction between the finger and objects is different for different fingers, these differences are monitored separately (Edin, Wrestling, & Johansson, 1992). That is, if one side of an object is covered with silk and contacted by the index finger and
Cortical Control of Hand-Object Interaction • 11 the other side of the object is covered with sandpaper and contacted by the thumb, each finger adjusts to the frictional conditions on its grip surface. Anesthesia of the fingers results in an increase in the dropping of objects (particularly small and slippery objects) and the application of significantly greater grip forces (Augurelle et al., 2003; Monzee, Lamarre & Smith, 2003; Westling & Johansson, 1984). The “just right grip,” which includes just enough margin of safety so the object will not be dropped, is lost. Anesthesia of the fingers also appears to prevent the exact alignment of the fingers on the object surface. Monzee, Lamarre, and Smith (2003) found that although these misalignments were too small to be visually apparent, they still caused enough of a tangential force so that the measured grip forces were close to the slip point. Therefore sensation from the fingers not only allows the application of appropriate grip forces and adjustments to small slips, this information also appears to help placement of the fingers to the most appropriate position for a secure grip. Because accurate sensory information is necessary for calibrating the “just right” grip force, children with reduced sensation in the hand, such as Katie, might have difficulty modulating grip and therefore manipulating small objects. This reduction in sensation has been found in children with cerebral palsy (see Eliasson, this volume), as well as children with developmental coordination disorders and attention deficit disorder (Pereira et al., 2001). Differences in establishing the “just right” grip also might be suspected in children with Down syndrome who have been shown to have impaired peripheral somatosensory function in the upper extremity (Brandt, 1996; Brandt & Rosen, 1995). Even in young children, the ability to adjust the grip force to the “just right” level is problematic. Young children, particularly those 4 years or younger, tend to use significantly larger grip forces when compared with adults (Forssberg et al., 1991). This may be one reason why an in-hand manipulation task such as moving a small peg from the palm to the fingers or turning a peg over in the fingers is difficult for children 4 years of age and younger (Pehoski, Henderson, & Tickel-Degnen, 1997a,b). This was a difficult task for Katie; she often dropped the manipulated object.
ROLE OF SOMATOSENSORY CORTEX IN MOTOR LEARNING Area 2 in the primary sensory cortex is connected to the primary motor cortex through corticocortical connections (Asanuma & Pavlides, 1997). Sensory information from the hand may be important to learn a new motor skill but not to retain a skill already learned. For
example, Pavlides, Miyashita, and Asanuma (1993) had monkeys learn a new motor task, but with each of the two hands subject to different conditions. In the first condition, the somatosensory cortex to one hand was lesioned. When the monkey had recovered from surgery, both hands were trained to retrieve food pellets falling at various velocities from a dispenser. The authors found that the hand contralateral to the lesion had difficulty learning the task and even when learned, never achieved the skill of the “normal” hand. In the second condition or experiment, the primary sensory cortex to the “normal” hand was lesioned. Despite this damage, the ability to perform the task with this hand remained. The authors concluded, “The corticocortical projections from the somatosensory to the motor cortex play an important role in learning new motor skills, but not in the execution of existing motor skills” (Pavlides, Miyashita, & Asanuma, 1993, p. 733). Practicing a task produces a vigorous circulation of impulses among the peripheral sensory inputs, somatosensory cortex, and primary motor cortex (Asanuma & Pavlides, 1997; Nadler, Harrison, & Stephens, 2000; Stefan et al., 2000). This specific input from the primary somatosensory cortex to the motor cortex is said to serve as a “teacher” (Asanuma & Pavlides, 1997). The “teacher” informs the motor cortex of the results of a movement so that eventually the exact combination and sequence of muscles needed for the task can be selected. Everyone has experienced clumsiness when learning a new skill. The movements are not smooth and unnecessary movements (and therefore muscles) are used when performing the task. As the task is practiced, these unnecessary movements are eliminated and an efficient, reproducible series of actions is seen. Try this activity. Pick up a pencil with your preferred hand with the fingers close to the eraser end rather than the writing end. Now move your fingers up the pencil shaft until they are in the proper position for writing. Try the same activity with your nonpreferred hand. Did you note a marked difference in the skill of this task on the two sides? Was the nonpreferred side awkward and clumsy? A possible interpretation of the study by Asanuma and Pavlides (1997) is that practice is one of the differences between the two hands in this task. The nonpreferred hand has not had an opportunity for sensory feedback to “teach” the motor cortex how to do the task most efficiently. It is not hard for people to understand how important sensory feedback is to hand function. Everyone has experienced the frustration of picking up a small object from the table with a Band-Aid covering the distal pad of one finger. Just think of how clumsy skilled motor acts of the hand would be if this reduction in sensation
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Part I • Foundation of Hand Skills
were experienced throughout the entire hand. One would have difficulty moving the fingers with skill and adjusting the hand to the “just right” grip so objects are not dropped.2 There might even be some difficulty learning a new motor task with the hands. Nonetheless actual engagement with objects is more complicated than just picking them up so they do not drop or manipulating them within the hand. This is particularly true for tool use. Preparation for grasp occurs even before the object is touched and is based on the observed characteristics of the object and the use that will be made of the object. Consideration of the posterior parietal lobe and connection with the premotor cortex is covered next.
THE TRANSFORMATION OF VISUALLY OBSERVED CHARACTERISTICS ABOUT OBJECTS INTO APPROPRIATE HAND CONFIGURATIONS: POSTERIOR PARIETAL LOBE AND VENTRAL PREMOTOR CORTEX Think for a moment what it would be like if one had an excellent mechanism for the control of finger movements and somatosensory feedback to guide the movements but did not have a mechanism for selecting the grasp appropriate for a particular object. There would be a lot of trial and error. Movements would be slow. A glass would be approached in the same way as a fork. The hand would land on an object and then “feel” for the appropriate grasp. One function that would help would be vision. Up until now vision has not been considered. The primary motor cortex has limited access to direct visual information (Jeannerod et al., 1995). Vision allows for the preparation of grasp before contact; therefore the hand could be preshaped to match objects of different shapes, sizes, and orientation. Any final adjustments could be made by somatosensory feedback on contact. This preshaping of the hand is one of the functions provided by a posterior parietal cortex–prefrontal lobe cortex circuit.
2
It should be noted that besides the neural mechanisms responsible for the “just right” grip, there are other ways to increase the friction at the finger–object interface, the oils or moisture of the fingers themselves. Washing and drying the hands (Johansson & Westling, 1984) or the introduction of chemicals that reduce sweating of the hands (Smith, Codoret, & St-Amour, 1997) cause an increase in the grip force.
ROLE OF I NFERIOR PARIETAL LOBE IN PRESHAPING OF THE HAND Almost all interactions with objects start with a reach. Reach is composed of two main parts, the transport of the hand and the preparation of the hand for grasp (see Rosblad, this volume). Each of these requires different visual information about the object. Reach requires the analysis of distance and direction. Preparation of the hand for grasp requires the analysis of the object’s shape, size, and orientation (Jeannerod et al., 1995). Try this: Place two objects of different sizes on the table, such as a paper clip and the box the paper clip comes in, then reach for each one. Note the difference in the hand opening for the larger as opposed to the smaller object. As the hand is brought toward the object, the fingers open to ready the hand for grasp, and this opening is calibrated to the size of the object to be grasped, although it is always a bit larger than the object itself (Jeannerod, 1981). Here is another activity. With one hand, hold a pencil out in front of you and reach for it with the other hand while the pencil is held in a vertical position and then with the pencil in a horizontal position. Did you rotate your forearm during the reach to accommodate the difference in orientation of the pencil (e.g., “thumb up” for the vertical position and “thumb down” for the horizontal position)? Not only is the hand opening “programmed” as a part of the reach, but forearm rotation and wrist position also are part of the pattern of the reach. All of this preparation ensures that a secure grasp is achieved once contact with the object is made (Jeannerod et al., 1995). The ability to scale the hand opening and orient the hand appropriately to an object is not seen in young infants. Changes to the orientation of the wrist or forearm to an object is seen at about 7 to 9 months of age (Lockman, Ashmead, & Bushnell, 1984; Morrongiello & Rocca, 1989; von Hofsten & FazelZandy, 1984; McCarthy et al., 2001) and adjusting the opening of the hand to changes in an object’s size at about 9 months of age (von Hofsten, 1979, 1991; von Hofsten & Ronnquist, 1988). The transformation of the visual image of an object into an appropriate hand opening and orientation is processed in the posterior parietal lobe. In a study of reach and grasp in monkeys, the timing of the firing of neurons in the posterior parietal lobe was compared with those of the primary somatosensory cortex (Debowy et al., 2001). The researchers found that the neurons in the posterior parietal lobe were more active during the approach stage as the hand was preshaped and before the hand touched the object. Most of the somatosensory neurons fired on contact with the
Cortical Control of Hand-Object Interaction • 13 object. Contact appeared to be the transition point from visually guided behavior to tactile guidance of the action. The posterior parietal lobe is composed of two parts, the superior and inferior parietal lobes (Figure 1-7). It is an important center for the integration of sensory information, particularly somatosensory and visual information. With respect to somatosensory input, this area completes the hierarchical processing of this information that started in the primary somatosensory cortex. The superior parietal lobe receives information from area 1 and more strongly from area 2 in the primary somatosensory cortex (Hyvarinen, 1982). The inferior parietal lobe’s sensory representation is more complex than the superior parietal lobe because it not only receives information from areas 1 and 2 and the superior parietal lobe, it also receives a great deal of information from the visual cortex; therefore this is an area where visual and somatosensory information converge (Hyvarinen, 1982; Mountcastle et al., 1975). Within the inferior parietal lobe is an area that has recently attracted much attention, the anterior intraparietal sulcus (see Figure 1-7). In this area are neurons related to grasping that fire preferentially to the shape, size, and orientation of objects (Sakata et al., 1995, 1999; Taira et al., 1990). Patients with lesions in this area have no difficulty in reaching but hand shaping is significantly disturbed and often there is no preshaping of the hand at all (Binkofski et al., 1998). Monkeys with reversible inactivation of this area also have difficulty grasping. Grasping in these animals often is achieved only after several corrections that rely on tactile feedback (Gallese et al., 1994). Binkofski et al. (1999) found neurons in the intraparietal sulcus active (along
Central sulcus
Primary somatosensory cortex Superior parietal lobe
with the ventral premotor area, superior parietal lobe, and secondary sensory cortex) when imaging studies were done of typical adults manipulating complex objects in their hands.
ROLE OF THE VENTRAL PREMOTOR CORTEX IN PRESHAPING OF THE HAND Registering information about an object’s size, shape, and orientation is important, but the parietal lobe is primarily a sensory area and this information must be transferred from sensory to motor areas for use in actual movement execution. The anterior interparietal sulcus has corticocortical connections with the ventral premotor area (Luppino et al., 1999) (Figure 1-8). The “description” of the object is used here to select the most appropriate grip. Neurons in the ventral premotor cortex area of monkeys, such as those in the anterior parietal sulcus, are selective in the type of objects that cause them to fire (Rizzolatti et al., 1988). In monkeys, many neurons in this area can be classified by their action (e.g., grasping, holding, tearing, or manipulating); grasping neurons are most represented. Many also are selective to the type of prehension used, such as a precision grip, finger prehension, or whole hand prehension. (These grips are the three most common grips seen in monkeys [Fadiga & Craighero, 2003].) Some neurons in this area are specific for different finger configurations within a grip type. They are also selective to what part of the grip movement they fire. Some discharge during the whole action with the object, others during finger closure, and others after contact with the object; therefore these neurons form a “vocabulary”
Primary motor cortex Ventral premotor cortex
Central sulcus
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Figure 1-7 Diagram of the intraparietal sulcus dividing the superior parietal lobe and inferior parietal lobe.
Figure 1-8 Diagram of ventral premotor area and relationship to primary motor cortex.
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Part I • Foundation of Hand Skills
of possible actions the hand can take on an object (see Rizzolatti & Fadiga, 1998, for a review). This vocabulary is related more to the goal of an action than to individual movements (e.g., a specific neuron might fire to “grasping” with the mouth and also with either hand) (Rizzolatti et al., 1988; Rizzolatti & Fadiga, 1998). The ventral premotor cortex is connected to the primary motor cortex and from there to the direct corticospinal fibers to hand muscles (Luppino et al., 1999). What differentiates the primary motor cortex from the ventral premotor cortex is that the latter stores motor schemata that are goal directed, whereas the primary motor area stores movements regardless of the action or context in which they are used (Rizzolatti & Fadiga, 1998). That is, the visual information processed in the anterior intraparietal sulcus about the three-dimensional characteristics of an object is sent to the ventral premotor cortex for the selection of grip and then to the motor cortex for sequencing of the actual muscles to be used. Neurons in the inferior premotor area are known to facilitate neural action in the primary motor cortex. Stimulation of a neuron in the hand area of the primary motor cortex of monkeys causes changes in the EMG reading from hand muscles, but stimulation of an inferior premotor neuron or inferior parietal neuron alone does not. If stimulation is first given to the premotor cortex and then to the primary motor cortex, the EMG hand muscle response is greater than when the motor cortex is stimulated alone. The authors indicate that this input might be part of the wider control system that helps shape the pattern of activity of different hand muscles for grasp of specific objects (Shimazu et al., 2004). If a small injection of an agent that temporarily inactivates neurons is placed in the ventral premotor cortex of monkeys, the results are similar to those seen with inactivation of the anterior interparietal sulcus. That is, the animal is able to use tactile feedback to succeed in an appropriate grasp when preshaping of the hand is absent, but only after contact with the object, This is particularly true for small objects (Fogassi et al., 2001). It is interesting that large lesions at this site also produced problems with hand shaping of the ipsilateral hand. Further, when monkeys with large lesions were presented with raisins placed in a board with two rows of six horizontally placed holes, the monkeys tended to pick up the raisins in the right holes with the right hand and those on the left with the left hand. They also tended to remove the raisin first from the holes ipsilateral to the injection site. When food was presented bilaterally, they always preferred the ipsilateral presentation.
USE-DEPENDENT ORGANIZATION OF THE I NFERIOR PARIETAL AND VENTRAL PREMOTOR CORTEX Although use-dependent changes have not been directly studied in either the anterior intraparietal sulcus or the ventral premotor area, it seems apparent that these areas are influenced by use. As an example, one of the most common types of grasping neurons found in the ventral premotor cortex in monkeys are those that respond to a precision grip, a grip formation that is not seen in young infant monkeys, but is seen with increasing regularity as monkeys get older (Lemon, 1993). Rizzolatti and Luppino (2001) suggest that the matching between the visually observed characteristics of an object and appropriate motor programs occurs early in life and is accomplished through processes that associate the intrinsic visual properties of the object with the grips that are effective in interacting with them.
THE I NFERIOR PARIETAL CORTEX AND TOOL USE Hand positioning to pick up an object requires a posture adapted to the features of the object (e.g., size, shape), but picking up an object to actually use it also requires that the grip anticipate what action will be performed. Think about the difference in hand position used when holding a pencil to punch a hole in a piece of cardboard as opposed to picking up a pencil to write. The posterior parietal lobe is implicated in this function. Sirigu et al. (1995) describe a patient with a bilateral lesion in the posterior parietal lobe who had normal sensory and motor functions, yet had a great deal of difficulty grasping tools. Figure 1-9 illustrates some of the patient’s problems grasping common objects, such as a nail clipper, spoon, and scissors. At home she had difficulty using objects in such tasks as brushing her teeth, locking her door, and cutting meat. What was of particular interest in this patient was that if the examiner corrected the patient’s grasp and the object was placed in her hand appropriately, she could perform with normal movement kinematics. Further, if the patient was asked to just grasp an object and not use it, appropriate preshaping of the hand and wrist to the object’s physical characteristics was seen. It was the capacity to match the grasp to the object’s use that seemed to be missing in this patient. Apparently the posterior parietal cortex is important for this function. Another feature of skilled tool use is that when the hand uses a tool, the tool becomes an extension of the hand. When one writes, one is not aware of the pen as a tool separate from the hand. Rather, it is an integral
Cortical Control of Hand-Object Interaction • 15
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Figure 1-9 Spontaneous hand use of a woman with a bilateral disturbance of the posterior parietal lobe as she attempts to use a: (A) lighter, (B) nail clipper, (C) soup spoon, and (D) scissors (successive attempts). (Redrawn from Sirigu A, Cohen L, Duhamel J, Pillon B, Dubois B, Agid Y [1995]. A selective impairment of hand posture for object utilization in apraxia. Cortex, 31:41–55.)
part of the automatic movements that create the letters. It appears that the sense of the tool as an extension of the hand has a neurologic correlate that includes the tool into the body scheme of the hand. Working with monkeys, Iriki, Tanaka, and Iwamura (1996) pointed out that the visual receptive fields of neurons within the anterior intraparietal sulcus changed when the monkey used a rake to obtain food pellets (Figure 1-10). Soon after the monkey began to use the rake, the visual field was seen to change to not only cover the area around the hand but also to include the total length of the rake. This did not happen when the animal only held the tool or just moved a stick back and forth. That is, when the rake was used as a tool, the rake and the body schema of the hand came to be represented together. When imaging studies were done of humans picking up a small object with tongs or with just the fingers, the intraparietal sulcus was again implicated in the tool use task (Inoue et al., 2001). It appears that the anterior intraparietal sulcus is an important area concerned with the preparation and grasp of objects and may be particularly important for tool use. This area has strong connections with the
ventral premotor area, which also appears to be important for hand use. There is one other function of the parietal lobe related to object interaction that should be mentioned, the guidance of movements when exploring an object manually. The term “tactile apraxia” has been used to define a problem in this area (Pause et al., 1989). In patients with tactile apraxia, exploratory movements are described as slow and clumsy and may consist of only squeezing the object (Binkofski et al., 2001; Pause & Freund, 1989; Valenza et al., 2001). This problem has been seen in a variety of parietal lesions (Binkofski et al., 2001; Pause & Freund, 1989; Valenza et al., 2001), including the primary somatosensory cortex (Motomura et al., 1990; Tomberg & Desmedt, 1999). The problem does not appear to be related to the severity of any somatosensory disturbances that might be present. That is, a patient with a significant sensory loss may be better able to manipulate an object for identification than a patient with better-preserved sensation (Pause et al., 1989; Valenza et al., 2001). Problems moving her finger around objects in a manual form identification task was one area with which Katie had difficulty. She tended to just
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Part I • Foundation of Hand Skills A
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Figure 1-10 A. Monkey using a rake to obtain a food pellet that was dispensed out of its reach from a container. B. Simple stick manipulation task in which the food pellet was delivered at a reachable distance as a reward for swinging the stick. (Redrawn from Obayashi S, Suhara T, Kawabe K, Okauchi, Maeda J, Akine Y, Onoe H, Iriki A (2001): Functional brain mapping of monkey tool use, Neuroimage 14: 853-861.)
hold the object. As one group of researchers said, “The parietal lobe is not only involved in the elaboration and further processing of somatosensory information, but also in the conception and generation of those motor programs required to collect this information.” (Pause et al., 1989, p. 1622).
SUMMARY AND THERAPEUTIC IMPLICATIONS This section reviews the covered information. The primary motor cortex is critical to the ability to move the fingers individually and speedily. Without this input, hand movements are characterized by varying degrees of muscle cocontraction so movements are stiff, awkward, and slow. This ability to “fractionate” movements of the hand is transmitted by the corticospinal tract, particularly through direct corticospinal connections to the motoneurons of hand muscles. Through intracortical connections of the various hand muscles in the primary motor cortex, movements used together come to be represented together. When a movement is performed, this action generates sensory feedback. Discrete information related to the movements is carried back to the primary sensory cortex by the dorsal columns. This information can then be fed back to the motor cortex via corticocortical connections so any necessary corrections of the movements can be made. Through practice, the correct combination and timing of muscles can be perfected through this mechanism. Once learned, feedback is much less important. This is not to say that everyday, learned movements are not dependent on sensory information. The ability to pick up an object and hold it with just
enough force so that it is not dropped is dependent on sensory input from the fingers. The exact placement of the fingers on an object after grasp is also dependent on sensory feedback. Humans have an important cortical loop for the control of skilled hand function and the interaction with objects, the primary motor cortex and primary sensory cortex connection (Figure 1-11). However, the described actions are relatively simple and human object use is not simple. The second cortical circuit between the posterior parietal lobe (particularly the anterior intraparietal sulcus) and the ventral premotor area is important in the selection of the appropriate grip patterns. As indicated, the inferior portion of the posterior parietal lobe receives both somatosensory information from the primary sensory cortex and visual information from the visual cortex, resulting in complex bimodal neurons (neurons that respond to both somatosensory and visual information). Vision information about an object provides information about the object’s size, shape, and orientation. This allows the hand to be preshaped to the object’s characteristics before contact. This visual information is transferred to the premotor area through corticocortical connections in which the appropriate grip pattern is chosen. The premotor area then sends this information to the primary motor cortex for the selection and timing of the necessary muscles. This in turn results in sensory information fed to the primary sensory cortex and back to the motor cortex, completing the circuit (see Figure 1-11). The anterior intraparietal sulcus of the posterior parietal lob also is important for incorporating the tool into the body schema of the hand, therefore making the tool an extension of the hand. It also should be noted that there are hand skills that have not been discussed in this chapter; many of these are covered in
Cortical Control of Hand-Object Interaction • 17
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B
Figure 1-11 A. Diagram of a somatosensory and a primary motor cortex circuit. (1) A message from the primary motor cortex is sent to the muscles via the corticospinal tract; (2) sensory feedback is sent through the dorsal column as a result of the movement (3) of sensory input to the primary somatosensory cortex; (4) sensory information is sent from the primary sensory cortex to the primary motor cortex for any necessary correction of the movement. B. Diagram of somatosensory, inferior parietal lobe, ventral premotor cortex, and motor cortex circuit. (1) Sensory information is sent to the inferior parietal lobe; (2) visual information also is transferred to the inferior parietal lobe; (3) information from the inferior parietal lobe is sent to the ventral premotor cortex; (4) the ventral premotor area transfers information to the primary motor cortex and from there to the corticospinal tract.
other chapters of this book (e.g., handedness, reaching, eye–hand coordination, and perceptual functions of the hand). This chapter has concentrated on the performance of the hand in hand–object interaction, and has not discussed the shoulder or postural support as background for these skilled movements. These are also important aspects of hand function. For example, Smith-Zuzovsky and Exner (2004) found that 6- and 7-year-old children who were positioned in furniture that was fitted to their size did significantly better on a test of in-hand manipulation than children using typical classroom furniture. In most natural movements the more proximal muscles provide the stability that allows skilled actions of the hand. Thus the corticospinal connections to proximal and distal muscles must cooperate (Turton & Lemon, 1999), but the roles of reach and postural functions are different and therefore so are the basic neural mechanisms that control them. The primary role of posture and the shoulder in skilled hand function is one of stability. If the shoulder lacks stability for hand function or the postural muscles cannot adequately support the trunk, then this needs to be addressed through mechanisms to increase stability and strength. Hand muscles also may need strengthening, but remember that the primary roles of the hand are to act, move, and perform with skill. If a child presents with shoulder instability, poor trunk support, and poor hand use, these should be worked on simultaneously. The hand should not wait until some minimal level of postural support is achieved. The choice of proper positioning and creative selection of activities can make it possible for the child to use his or her hands even when postural support is poor.
As discussed, the cortical reorganization responsible for skilled learning, particularly as it relates to hand– object interaction, is use dependent. It is through use that functional patterns of movement or the muscles necessary for the action come to be represented together. The same is true of patterns of somatosensory input. Surfaces that are used together come to be represented together. This happens through practice. Also as indicated, this structural reorganization is best accomplished through tasks that require skill or the learning of an activity. It also requires attention to the task. Passive movements and strength training are much less effective in driving this cortical reorganization. Children with poor hand skills, like Katie, often avoid or are so poor at fine motor tasks that they may actually get less practice than their peers. Skill requires attention to the activity and is facilitated when there is an interest in the outcome. Children with poor hand skills may need help to select and adapt to activities to meet their level of performance and interest. The art of therapy is being able to provide activities that challenge the child within the scope of his or her abilities and elicit the child’s enthusiastic cooperation.
REFERENCES Ageranioti-Belanger SA, Chapman CE (1992). Discharge properties of neurons in the hand area of primary somatosensory cortex in monkeys in relation to the performance of an active tactile discrimination task. II. Area 2 as compared with areas 3b and 1. Experimental Brain Research, 91:207–228. Asanuma H, Pavlides C (1997). Neurobiological basis of motor learning in mammals. Neuroreport, 8:i–vi.
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Augurelle A, Smith AM, Lejeune T, Thonnard J (2003). Importance of cutaneous feed back in maintaining a secure grip during manipulation of hand-held objects. Journal of Neurophysiology, 89:665–671. Bennett KM, Lemon RN (1996). Corticomotoneuronal contribution to the fractionation of muscle activity during precision grip in the monkey. Journal of Neurophysiology, 75:1826–1842. Binkofski F, Buccino G, Posse S, Seitz RJ, Rizzolatti G, Freund H (1999). A fronto-parietal circuit for object manipulation in man: evidence from an fMRI-study. European Journal of Neuroscience, 11:3276–3286. Binkofski F, Dohle C, Posse S, Stephan KM, Heftner H, Seitz RJ, Freund HJ (1998). Human anterior intraparietal area subserves prehension: A combined lesion and functional MRI activation study. Neurology, 50:1253–1259. Binkofski F, Kunesch E, Classen J, Seitz RJ, Freund H (2001). Tactile apraxia: Unimodal apractic disorder of tactile object exploration associated with parietal lobe lesions. Brain, 124:132–144. Brandt BR (1996). Impaired tactual perception in children with Down’s syndrome. Scandinavian Journal of Psychology, 37:12–16. Brandt BR, Rosen I (1995). Impaired peripheral somatosensory function in children with Down syndrome. Neuropediatrics, 3:310–312. Brochier T, Boudreau MJ, Smith AM (1999). The effect of muscimol inactivation of small regions of motor and somatosensory cortex on independent finger movements and force control in the precision grip. Experimental Brain Research, 128:31–40. Butefisch CM (2004). Plasticity in the human cerebral cortex: Lessons from the normal brain and from stroke. Neuroscientist, 10:163–173. Classen J, Liepert J, Wise SP, Hallett M, Cohen LG (1998). Rapid plasticity of human cortical movement representation induced by practice. Journal of Neurophysiology, 79:1117–1123. Darian-Smith I, Burman K, Darian-Smith C (1999). Parallel pathways mediating manual dexterity in the macaque. Experimental Brain Research, 128:101–108. Debowy DJ, Ghosh S, Ro JY, Gardner EP (2001). Comparison of neuronal firing rates in somatosensory and posterior parietal cortex during prehension. Experimental Brain Research, 137:269–291. deJong BM, Coert JH, Stenekes MW, Leenders KL, Paans AM, Nicolai JP (2003). Cerebral reorganization of human hand movements after dynamic immobilization. Neuroreport, 14:1693–1696. Denckla MB (1974). Development of motor co-ordination in normal children. Developmental Medicine and Child Neurology, 16:729–741. Edin BB, Westling G, Johansson RS (1992). Independent control of human finger-tip forces at individual digits during precision lifting. Journal of Physiology, 450:547–564. Ehrsson HH, Kuhtz-Buschbeck JP, Forssberg H (2002). Brain regions controlling nonsynergistic versus synergistic movements of the digits: A functional magnetic resonance imaging study. Journal of Neuroscience, 22:5074-5080. Evans AL, Harrison LM, Stephens JA (1990). Maturation of the cutaneomuscular reflex recorded from the first dorsal interosseous muscle in man. Journal of Physiology, 428:425–440.
Fadiga L, Craighero L (2003). New insight on sensorimotor integration: From hand action to speech perception. Brain and Cognition, 53:514–524. Fogassi L, Gallese V, Buccino G, Craighero G, Fadiga L, Rizzolatti G (2001). Cortical mechanisms for the visual guidance of hand grasping movements in the monkey: A reversible inactivation study. Brain, 124:571–583. Forssberg H, Eliasson AC, Kinoshita H, Johansson RS, Westling G (1991). Development of human precision grip I. Basic coordination of force. Experimental Brain Research, 85:451–457. Gallese V, Murata A, Kaseda M, Niki N, Sakata H (1994). Deficit of hand preshaping after muscimol injection in monkey parietal cortex. Neuroreport, 5:1525–1529. Godde B, Ehrhardt J, Braun C (2003). Behavioral significance of input-dependent plasticity of human somatosensory cortex. Neuroreport, 14:543–546. Hashimoto I, Suzuki A, Kimura T, Iguchi Y, Tanosaki M, Takino R, Haruta Y, Taira M (2004). Is there trainingdependent reorganization of digit representation in area 3b of string players? Clinical Neurophysiology, 115:435–437. Hikosaka O, Tanaka, M, Sakamoto M, Iwamura Y (1985). Deficits in manipulative behaviors induced by local injection of muscimol in the first somatosensory cortex of the conscious monkey. Brain Research, 325:375–380, Huntley GW, Jones E (1991). Relationship of intrinsic connections to forelimb movement representation in monkey motor cortex: A correlative anatomic and physiological study. Journal of Neurophysiology, 66:390–413. Hyvarinen J (1982). Posterior parietal lobe of the primate brain. Psychological Reviews, 62:1060–1129. Inoue K, Kawashima R, Sugiura M, Ogawa A, Schormann T, Zilles K, Fukuda H (2001). Activation in the ipsilateral posterior parietal cortex during tool use: A PET study. Neuroimage, 14:1469–1475. Inoue K, Wang X, Tamura Y, Kaneoke Y, Kakigi R (2004). Serial processing in the human somatosensory system. Cerebral Cortex, 14:851–857. Iriki A, Tanaka M, Iwamura Y (1996). Coding of modified body schema during tool use by macaque postcentral neurones. Neuroreport, 7:2325–2330. Iwamura Y (1998). Hierarchical somatosensory processing. Current Opinions in Neurobiology, 8:522–528. Iwamura Y, Tanaka M, Sakamoto M, Hikosaka O (1985). Functional surface integration, submodality convergence and tactile feature detection in area 2 of the monkey somatosensory cortex. Experimental Brain Research, Suppl. 10:44–58. Jackson A, Lemon RN (2001). Motor control: Forcing neurons to change. Current Biology, 11:R708–R709. Jeannerod M (1981) Intersegmental coordination during reaching at natural visual objects. In J Long, A Baddeley, editors: Attention and performance IX. Hillsdale, NJ, LEA. Jeannerod M, Arbid M, Rizzolatti G, Sakata H (1995). Grasping objects: The cortical mechanisms of visuomotor transformation. Trends in Neuroscience, 18:314–320. Jeannerod M, Michel F, Prablanc C (1984). The control of hand movements in a case of hemianaesthesia following a parietal lesion. Brain, 107:899–920. Johansson RS, Westling G (1984). Role of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects. Experimental Brain Research, 56:550–564.
Cortical Control of Hand-Object Interaction • 19 Johansson RS, Westling G (1987). Signals in tactile afferents from the fingers eliciting adaptive motor responses during precision grip. Experimental Brain Research, 66:141–154. Karni A, Meyer G, Rey-Hipolito C, Jezzard P, Adams M, Turner R, Ungerleider L (1998). The acquisition of skilled motor performance: Fast and slow experience driven changes in primary motor cortex. Proceedings of the National Academy of Sciences, 95:861–868. Kleim JA, Lussing E, Schwarz ER, Comery TA, Greenough WT (1996). Synaptogenesis and FOS expression in the motor cortex of the adult rat after motor skill learning. The Journal of Neuroscience, 16:4529–4535. Kuypers HG (1981). Anatomy of the descending pathways. In JM Brookhart, VB Mountcastle editors: Handbook of physiology, section I, vol. II: Motor control, part I. Bethesda, MD, American Physiological Society. Lang CE, Schieber MH (2003). Reduced muscle selectivity during finger movements in humans after damage to the motor cortex or corticospinal tract. Journal of Neurophysiology, 91:1722–1733. Lemon RN (1993). Cortical control of the primate hand. Experimental Physiology, 78:263–301. Lemon RN (1999). Neural control of dexterity: What has been achieved? Experimental Brain Research, 128:6–12. Lemon RN, Maier MA, Armand J, Kirkwood PA, Yang HW (2002). Functional differences in corticospinal projections from macaque primary motor cortex and supplementary motor area. Advance Experimental Medical Biology, 508:423–434. Liepert J, Bauder H, Wolfgang HR, Miltner WH, Taub E, Weiller C (2000). Treatment-induced cortical reorganization after stroke in humans. Stroke, 31:1210–1216. Lockman JJ, Ashmead DH, Bushnell EW (1984). The development of anticipatory hand orientation during infancy. Journal of Experimental Child Psychology, 37:176–186. Long C, Conrad PW, Hall EA, Furler SL (1970). Intrinsicextrinsic muscle control of the hand in power grip and precision handling. Journal of Bone and Joint Surgery, 52A:853–867. Lotze M, Braun C, Birbaumer N, Anders S, Cohen LG (2003). Motor learning elicited by voluntary drive. Brain, 126:866–872. Luppino G, Murata A, Govoni P, Matelli M (1999). Largely segregated parietofrontal connections linking rostral intraparietal cortex (areas AIP and VIP) and the ventral premotor cortex (area F5 and F4). Experimental Brain Research, 128:181–187. Maier M, Armand J, Kirkwood P, Yang H, Davis J, Lemon R (2002). Differences in the corticospinal projections from primary motor cortex and supplementary motor area to macaque upper limb motoneurons: an anatomical and electrophysiological study. Cerebral Cortex, 12:281–296. Martin JH, Choy M, Pullman S, Meng Z (2004). Corticospinal system development depends on motor experience. Journal of Neuroscience, 24:2122–2132. McCarthy ME, Clifton RK, Ashmead DH, Lee P, Goubet N (2001). How infants use vision for grasping objects. Child Development, 72:973–987 Monzee J, Lamarre Y, Smith AM (2003). The effect of digital anesthesia on force control using a precision grip. Journal of Neurophysiology, 89:672–683. Moore CI, Stern CE, Corkin S, Fischl B, Gray AC, Rosen B, Dale AM (2000). Segregation of somatosensory
activation in the human rolandic cortex using fMRI. Journal of Neurophysiology, 84:558–569. Morrongiello BA, Rocca PT (1989). Visual feedback and anticipatory hand orientation during infants’ reaching. Perceptual and Motor Skills, 69:787–802. Motomura N, Yamodori A, Asaba H, Sakai T, Swada T (1990). Failure to manipulate objects secondary to active touch disturbance. Cortex, 26:473–477. Mountcastle VB, Lynch LC, Georgopoulos A, Sakata H, Aguna C (1975). Posterior parietal association cortex of the monkey: Command functions for operation within extra personal space. Journal of Neurophysiology, 38:871–908. Muir RB (1985). Small hand muscles in precision grip: A corticospinal prerogative? In AW Goodwin, I DarianSmith, editors: Hand function and the neocortex. New York, Springer-Verlag. Nadler MA, Harrison LM, Stephens JA (2000). Acquisition of a new motor skill is accompanied by changes in cutaneomuscular reflex responses recorded from finger muscles in man. Experimental Brain Research, 134:246–254. Nakajima K, Maier MA, Kirkwood PA, Lemon RN (2000). Striking differences in transmission of corticospinal excitation to upper limb motoneurons in two primate species. Journal of Neurophysiology, 84:698–709. Nudo RJ, Milliken G, Jenkins WM, Merzenich MM (1996). Use dependent alterations of movement representations in primary motor cortex of adult squirrel monkeys. Journal of Neuroscience, 15:785–807. Obayashi S, Suhara T, Kawabe K, Okauchi T, Maeda J, Akine Y, Onoe H, Iriki A (2001). Functional brain mapping of monkey tool use. Neuroimage, 14:853–861. Paillard J (1993). The hand and the tool: The functional architecture of human technical skills. In A Berthelet, J Chavillon, editors: The use of tools by humans and nonhuman primates. Oxford, UK, Clarendon Press. Pascual-Leone A, Grafman J, Hallett M (1994) Modulation of cortical motor output maps during development of implicit and explicit knowledge. Science, 263:1287–1291. Pause M, Freund H (1989). Role of the parietal cortex for sensorimotor transformation: Evidence from clinical observation. Brain Behavior and Evolution, 33:136–140. Pause M, Kunesch E, Binkofski F, Freund H (1989). Sensorimotor disturbances in patients with lesions of the parietal cortex. Brain, 112:1599–1625. Pavlides C, Miyashita E, Asanuma H (1993). Projection from the sensory cortex is important in learning motor skills in the monkey. Journal of Neurophysiology, 70:733–741. Pehoski C, Henderson A, Tickel-Degnen L (1997a). Inhand manipulation in young children: Rotation of an object in the fingers. American Journal of Occupational Therapy, 51:544–552. Pehoski C, Henderson A, Tickel-Degnen L (1997b). Inhand manipulation in young children: Translation movements. American Journal of Occupational Therapy, 51:719–728. Pereira H, Landgren M, Gillberg C, Forssberg H (2001). Parametric control of fingertip forces during precision grip lifts in children with DCD (developmental coordination disorder) and DAMO (deficits in attention, motor control, and perception). Neuropsychologia, 39:478–488. Plautz EJ, Milliken GW, Nudo RJ (2000). Effects of repetitive motor training on movement representation in
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adult squirrel monkeys: Role of use versus learning. Neurobiology of Learning and Memory, 74:27–55. Recanzone GH, Merzenich MM, Jenkins WM, Grajski KA, Dinse HR (1992). Topographic reorganization of the hand representation in cortical area 3b of owl monkeys trained in a frequency-discrimination task. Journal of Neurophysiology, 67:1031–1056. Remple MS, Bruneau RM, VandenBerg PM, Goertzen C, Kleim JA (2001). Sensitivity of cortical movement representations to motor experience: Evidence that skill learning but not strength training induces cortical reorganization. Behavioral Brain Research, 123:133–141. Rizzolatti R, Camarda L, Fogassi M, Gentilucci M, Luppino G, Matalli M (1988). Functional organization of inferior area 6 in the macaque monkey: II. area F5 and the control of distal movements. Experimental Brain Research, 71:491–507. Rizzolatti G, Fadiga L (1998). Grasping objects and grasping action meaning: the dual role of monkey rostroventral premotor cortex (area F5). In JA Goode, editor: Sensory guidance of movement. Novartis Foundation Symposium, Chichester, UK, Wiley. Rizzolatti G, Luppino G (2001). The cortical motor system. Neuron, 31:889–901. Rouiller EM, Yu XH, Moret V, Tempini A, Wiesendanger M, Liang F (1998). Dexterity in adult monkeys following early lesions of the motor cortical hand area: The role of cortex adjacent to the lesion. European Journal of Neuroscience, 10:729–740. Sakata H, Iwamura Y (1978). Cortical processing of tactile information in the first somatosensory and parietal association areas in the monkey. In G Gordon, editor: Active touch. New York, Pergamon Press. Sakata H, Taira M, Kusunoki M, Murata A, Tsutsui K, Tanaka Y, Shein W, Miyashita Y (1999). Neural representation of three-dimensional features of manipulation objects with stereopsis. Experimental Brain Research, 128:160–169. Sakata H, Taira M, Murata A, Mine S (1995). Neural mechanisms of visual guidance of hand action in the parietal cortex of the monkey. Cerebral Cortex, 5:429–438. Sanes JN, Donoghue JP (2000). Plasticity and primary motor cortex. Annual Review of Neuroscience, 23:393–415. Scheibel A, Conrad T, Perdue S, Tomiyasu U, Wechsler A (1990). A quantitative study of dendrite complexity in selected areas of the human cerebral cortex. Brain and Cognition, 12:85–101. Schieber MH, Poliakov AV (1998). Partial inactivation of the primary motor cortex hand area: Effects on individual finger movements. Journal of Neuroscience, 18:9038–9054. Schlaug G, Knorr U, Seitz R (1994). Inter-subject variability of cerebral activations in acquiring a motor skill: A study with positron emission tomography. Experimental Brain Research, 98:523–534. Shimazu H, Maier MA, Cerri G, Kirkwood PA, Lemon RN (2004). Macaque ventral premotor cortex exerts powerful
facilitation of motor cortex output to upper limb motoneurons. Journal of Neuroscience, 24:1200–1211. Siddiqui A (1995). Object size as a determinant of grasping in infancy. Journal of Genetic Psychology, 156:345–358. Sirigu A, Cohen L, Duhamel J, Pillon B, Dubois B, Agid Y (1995). A selective impairment of hand posture for object utilization in apraxia. Cortex, 31:41–55. Smith AM, Codoret G, St-Amour D (1997). Scopolamine increases prehensile force during object manipulation by reducing palmer sweating and decreasing skin friction. Experimental Brain Research, 114:578–583. Smith-Zuzovsky N, Exner C (2004). The effect of seated positioning quality on typical 6- and 7-year-old children’s object manipulation skills. America Journal of Occupational Therapy, 58:380–388. Stefan K, Kunesch E, Cohen LG, Benecke R, Classen J (2000). Induction of plasticity in the human motor cortex by paired associative stimulation. Brain, 123:572–584. Taira M, Mine S, Georgopoulos AP, Murata A, Sakata H (1990). Parietal cortex neurons of the monkey related to the visual guidance of hand movements. Experimental Brain Research, 83:29–36. Taub E, Morris DM (2001). Constraint-induced movement therapy to enhance recovery after stroke. Current Atherosclerosis Report, 3:279–286. Tomberg C, Desmedt JE (1999). Failure to recognize objects by active touch (astereognosia) results from lesions of parietal cortex representation of finger kinaesthesia. The Lancet, 354:393–394. Turton A, Lemon RN (1999). The contribution of fast corticospinal input to the voluntary activation of proximal muscles in normal subjects and in stroke patients. Experimental Brain Research, 129:559–572. Valenza N, Ptak R, Zimine I, Badan M, Lazeyras F, Schnider A (2001). Dissociated active and passive tactile shape recognition: A case study of pure tactile apraxia. Brain, 124:2287–2298. von Hofsten C (1979). Development of visually directed reaching: The approach phase. Journal of Human Movement Studies, 5:160–178. von Hofsten C (1991). Structuring of early reaching movements: A longitudinal study. Journal of Motor Behavior, 23:280–292. von Hofsten C, Fazel-Zandy S (1984). Development of visually guided hand orientation in reaching. Journal of Experimental Child Psychology, 38:208–219. von Hofsten C, Ronnquist L (1988). Preparation for grasping on object: A developmental study. Journal of Experimental Psychology and Human Perceptual Performance, 14:610 –621. Westling G, Johansson JS (1984). Roles of glabrous skin receptors and sensorimotor memory in automatic control of precision grip when lifting rougher or more slippery objects. Experimental Brain Research, 56:550–564. Xerri C, Merzenich MM, Jenkins W, Santucci S (1999). Representational plasticity in cortical area 3b paralleling tactual-motor skill acquisition in adult monkey. Cerebral Cortex, 9:264–276.
Chapter
2
ANATOMY AND KINESIOLOGY OF THE HAND James W. Strickland
CHAPTER OUTLINE
EMBRYONIC DEVELOPMENT
EMBRYONIC DEVELOPMENT
Inspection of a normal newborn’s hands never ceases to evoke awe and wonderment. The tiny nails punctuating the ends of intricately formed fingers and opposable thumbs, each delicately marked with familiar patterns of joint wrinkles, immediately identify the newcomer as human. All of the ingredients that eventually provide an unbelievably extensive continuum of function from exquisitely fine dexterity to great power are present in the tiny waving arms and hands. However, the normal embryonic process through which the upper extremities develop is both predictable and consistent (Arey, 1980; Bora, 1986; Bunnell, 1944; Moore, 1982). Upper limb buds are discernible at 4 weeks of gestation. The scapula, humerus, radius, and ulna are apparent at 5 weeks as cartilage, and by 6 weeks upper arm, forearm, and hand divisions are present. Also at 6 weeks the webbed swellings of the three central digits appear and are soon followed by the two border digits. The metacarpals are present as cartilage, as are the proximal phalanges of the index through small fingers. Initially, each extremity is aligned longitudinally with the body trunk, but at 7 weeks the arms rotate outward and forward at the shoulder level to assume a hand-toface position with the flexor surface of the forearm and hand turned inward toward the body and the extensor surface turned outward. Elbows and wrists are slightly flexed. Innervation of the limbs has already occurred at this point, and vessels extend to the distal extremity. Muscles, muscle groups, joint hollows, and digital cleavages, including thumb differentiation, are also present at 7 to 8 weeks. Webbing between the digits diminishes, and the fingers and thumb are independent of each other by 8 weeks. Carpal bones are cartilaginous, and the os centrale fuses to the scaphoid at 8 weeks.
ANATOMY OF THE FULLY DEVELOPED HAND Osseous Structures Joints Muscles and Tendons Nerve Supply Skin and Subcutaneous Fascia Functional Patterns
One cannot expect to adequately understand the development and function of the hand and arm without a solid working knowledge of the intricate anatomic and kinesiologic relationships of the upper extremity, including the embryonic growth stages through which the extremity progresses. Only through comprehension of the normal formation and anatomy of the human hand can one adequately develop an appreciation for the disturbance in function that accompanies injury, disease, or dysfunction. It is appropriate, therefore that an early chapter in a book devoted to development of fine motor coordination be concerned with the embryology, anatomy, kinesiology, and biomechanics of the hand. Because it is impossible in this chapter to review in great detail the enormous amount of literature that has been written about these fields of knowledge, readers are directed to the Suggested Readings.
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Part I • Foundation of Hand Skills
For the remainder of gestation after 8 weeks, limb changes primarily involve growth of already present structures.
ANATOMY OF THE FULLY DEVELOPED HAND The anatomy of the hand must be approached in a systematic fashion with individual consideration of the osseous structures, joints, musculotendinous units, and nerve supply. However, it is obvious that the systems do not function independently, but that the integrated presence of all these structures is necessary for normal hand function. In presenting this material, this chapter strays into the important mechanical and kinesiologic considerations that result from the unique anatomic arrangement of the hand.
OSSEOUS STRUCTURES The unique arrangement and mobility of the bones of the hand (Figure 2-1) provide a structural basis for its enormous functional adaptability. The osseous skeleton consists of eight carpal bones divided into two rows: The proximal row articulates with the distal radius and ulna (with the exception of the pisiform, which lies palmar to and articulates with the triquetrum); the distal four carpal bones in turn articulate with the five
metacarpals. Two phalanges complete the first ray, or thumb unit, and three phalanges each comprise the index, long, ring, and small fingers. These 27 bones, together with the intricate arrangement of supportive ligaments and contractile musculotendinous units, are arranged to provide both mobility and stability to the various joints of the hand. Although the exact anatomic configuration of the bones of the hand need not be memorized in detail, it is important that one should develop knowledge of the position and names of the carpal bones, metacarpals, and phalanges and an understanding of their kinesiologic patterns to proceed with the management of many hand problems. The bones of the hand are arranged in three arches (Figure 2-2), two transversely oriented and one that is longitudinal. The proximal transverse arch, the keystone of which is the capitate, lies at the level of the distal part of the carpus and is reasonably fixed, whereas the distal transverse arch passing through the metacarpal heads is more mobile. The two transverse arches are connected by the rigid portion of the longitudinal arch consisting of the second and third metacarpals, the index and long fingers distally, and the central carpus proximally. The longitudinal arch is completed by the individual digital rays, and the mobility of the first, fourth, and fifth rays around the second and third allows the palm to flatten or cup itself to accommodate objects of various sizes and shapes. To a large extent the intrinsic muscles of the hand are responsible for changes in the configuration of the
Distal phalanx
Middle phalanx
Proximal phalanx
Metacarpal
Hamate Pisiform Triquetrum
A
Trapezoid Capitate Trapezium Scaphoid Lunate
Hamate Triquetrum
B
Figure 2-1 Bones of the right hand. A. Palmar surface. B. Dorsal surface. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
Anatomy and Kinesiology of the Hand • 23 Distal transverse arch
Proximal transverse arch
Distal transverse arch Longitudinal arch
A
B
Proximal transverse arch
Figure 2-2 A. Skeletal arches of the hand. The proximal transverse arch passes through the distal carpus; the distal transverse arch, through the metacarpal heads. The longitudinal arch is made up of the four digital rays and the carpus proximally. B. Proximal and distal transverse arches. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
osseous arches. Collapse in the arch system can contribute to severe disability and deformity. Flatt (1979, 1983, 1995) has pointed out that grasp is dependent on the integrity of the mobile longitudinal arches and when destruction at the carpometacarpal joint, metacarpophalangeal joint, or proximal interphalangeal joint interrupts the integrity of these arches, crippling deformity may result.
JOINTS The multiple complex articulations among the distal radius and ulna, the eight carpal bones, and the metacarpal bases comprise the wrist joint, whose proximal position makes it the functional key to the motion at the more distal hand joints of the hand. Functionally the carpus transmits forces through the hand to the forearm. The proximal carpal row consisting of the scaphoid (navicular), lunate, and triquetrum articulates distally with the trapezium, trapezoid, capitate, and hamate; there is a complex motion pattern that relies both on ligamentous and contact surface constraints. The major ligaments of the wrist (Figure 2-3) are the palmar and intracapsular ligaments. There are three strong radial palmar ligaments: the radioscaphocapitate or “sling” ligament, which supports the waist of the scaphoid; the radiolunate ligament, which supports the lunate; and the radioscapholunate ligament, which connects the scapholunate articulation with the palmar portion of the distal radius. This ligament functions as a checkrein for scaphoid flexion and extension. The ulnolunate ligament arises intra-articularly from the triangular articular meniscus of the wrist joint and inserts on the lunate and, to a lesser extent, the triquetrum. The radial and ulnar collateral ligaments are capsular ligaments, and V-shaped ligaments from the capitate to
the triquetrum and scaphoid have been termed the deltoid ligaments. Dorsally, the radiocarpal ligament connects the radius to the triquetrum and acts as a dorsal sling for the lunate, maintaining the lunate in apposition to the distal radius. Further dorsal carpal support is provided by the dorsal intracarpal ligament. These strong ligaments combine to provide carpal stability while permitting the normal range of wrist motion. The distal ulna is covered with an articular cartilage (Figure 2-3, C) over its most dorsal, palmar, and radial aspects, where it articulates with the sigmoid or ulnar notch of the radius. The triangular fibrocartilage complex describes the ligamentous and cartilaginous structure that suspends the distal radius and ulnar carpus from the distal ulna. Blumfield and Champoux (1984) have indicated that the optimal functional wrist motion to accomplish most activities of daily living is from 10° of flexion to 35° of extension. Taleisnik (1976a,b, 1985a,b, 1992) has emphasized the importance of considering the wrist in terms of longitudinal columns (Figure 2-4). The central, or flexion extension, column consists of the lunate and the entire distal carpal row; the lateral, or mobile, column comprises the scaphoid alone; and the medial, or rotation, column is made up of the triquetrum. Wrist motion is produced by the muscles that attach to the metacarpals, and the ligamentous control system provides stability only at the extremes of motion. The distal carpal row of the carpal bones is firmly attached to the hand and moves with it. Therefore during dorsiflexion the distal carpal row dorsiflexes, during palmar flexion it palmar flexes, and during radial and ulnar deviation it deviates radially or ulnarly. As the wrist ranges from radial to ulnar deviation, the proximal carpal row rotates in a dorsal direction, and a simultaneous
24
Part I • Foundation of Hand Skills Deltoid ligaments Space of Poirier
Lunotriquetral ligament
Radioscaphocapitate ligament Vestigial ulnar collateral ligament
Scapholunate ligament Radial collateral ligament
Ulnocarpal meniscus homologue
Radiolunate ligament (radiolunotriquetral)
Ulnolunate ligament (ulnolunate-triquetral) Radioscapholunate ligament (ligament of Testut and Kuenz)
A
C
H
Td
Tm
P Dorsal intercarpal ligament
1
Tq S L
Dorsal radiocarpal ligament (radiotriquetral)
7
4
2
3
5 6
B
C
Figure 2-3 Ligamentous anatomy of the wrist. A. Palmar wrist ligaments. B. Dorsal wrist ligaments. C. Dorsal view of the flexed wrist, including the triangular fibrocartilage. 1, Ulnar collateral ligament; 2, retinacular sheath; 3, tendon of extensor carpi ulnaris; 4, ulnolunate ligament; 5, triangular fibrocartilage; 6, ulnocarpal meniscus homologue; 7, palmar radioscaphoid lunate ligament. P, Pisiform; H, hamate; C, capitate; Td, trapezoid; Tm, trapezium; Tq, triquetrum; L, lunate; S, scaphoid. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
translocation of the proximal carpus occurs in a radial direction at the radiocarpal and midcarpal articulations. This combined motion of the carpal rows has been called the rotational shift of the carpus. It was once taught that palmar flexion takes place to a greater extent at the radiocarpal joint and secondarily in the midcarpal joint, but because dorsiflexion occurs primarily at the midcarpal joint and only secondarily at the radiocarpal articulation, this now appears to be a significant oversimplification. The complex carpal kinematics are beyond the scope of this chapter, and the reader is referred to the works of Weber (1988),
Taleisnik (1985a,b), Lichtman and Alexander (1988), and Cooney, Linscheid, and Dobyns (1998) to gain a thorough understanding of this difficult subject. The articulation between the base of the first metacarpal and the trapezium (Figure 2-5) is a highly mobile joint with a configuration thought to be similar to that of a saddle. The base of the first metacarpal is concave in the anteroposterior plane and convex in the lateral plane, with a reciprocal concavity in the lateral plane and an anteroposterior convexity on the opposing surface of the trapezium. This arrangement allows the positioning of the thumb in a wide arc of
Anatomy and Kinesiology of the Hand • 25
Central column Medial column
Lateral column
First metacarpal
A
Figure 2-4 Columnar carpus. The scaphoid is the mobile or lateral column. The central, or flexion extension, column comprises the lunate and the entire distal carpal row. The medial, or rotational, column comprises the triquetrum alone. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
B Figure 2-6 A. Multiple planes of motion (arrows) that occur at the carpometacarpal joint of the thumb. B. The thumb moves (arrow) from a position of adduction against the second metacarpal to a position of palmar or radial abduction away from the hand and fingers and can then be rotated into positions of opposition and flexion. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
Figure 2-5 Saddle-shaped carpometacarpal joint of the thumb. A wide range of motion (arrows) is permitted by the configuration of this joint. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
motion (Figure 2-6), including flexion, palmar and radial abduction, adduction, and opposition. The ligamentous arrangement about this joint, while permitting the wide circumduction, continues to provide stability at the extremes of motion, allowing the thumb to be brought into a variety of positions for pinch and grasp, but maintaining its stability during these functions. The articulations formed by the ulnar half of the hamate and the fourth and fifth metacarpal bases allow a modest amount of motion (15° at the fourth carpometacarpal joint and 25° to 30° of flexion and extension at the fifth carpometacarpal joint). A resulting “palmar descent” of these metacarpals occurs during strong grasp. The metacarpophalangeal joints of the fingers are diarthrodial joints with motion permitted in three
planes and combinations thereof (Figure 2-7). The cartilaginous surfaces of the metacarpal head and the bases of the proximal phalanges are enclosed in a complex apparatus consisting of the joint capsule, collateral ligaments, and the anterior fibrocartilage or palmar plate (Figure 2-8). The capsule extends from the borders of the base of the proximal phalanx proximally to the head of the metacarpals beyond the cartilaginous joint surface. The collateral ligaments, which reinforce the capsule on each side of the metacarpophalangeal joints, run from the dorsolateral side of the metacarpal head to the palmar lateral side of the proximal phalanges. These ligaments form two bundles, the more central of which is called the cord portion of the collateral ligament and inserts into the side of the proximal phalanx; the more palmar portion joins the palmar plate and is termed the accessory collateral ligament. These collateral ligaments are somewhat loose with the metacarpophalangeal joint in extension, allowing for considerable “play” in the side-to-side motion of the digits (Figure 2-9). With the metacarpophalangeal joints in full flexion, however, the cam configuration of the metacarpal head tightens the collateral ligaments and limits lateral mobility of the digits. This alteration in tension becomes an important factor in immobilization of the metacarpophalangeal joints for any length of time, because the secondary
26
Part I • Foundation of Hand Skills Collateral ligament (loose in extension) Hinge (anteroposterior motion)
Diarthrodial (multiplane motion)
Palmar plate
Membranous portion of palmar plate (folds in flexion)
Figure 2-7 Joints of the phalanges. The diarthrodial configuration of the metacarpophalangeal joint permits motion in multiple planes, whereas the biconcave-convex hinge configuration of the interphalangeal joints restricts motion to the anteroposterior plane. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
Cord portion of collateral ligaments
Cord portion of collateral ligaments
Accessory collateral ligament
Accessory collateral Palmar ligaments Palmar fibrocartilaginous fibrocartilaginous plates plates
Figure 2-8 Ligamentous structures of the digital joints. The collateral ligaments of the metacarpophalangeal and interdigital joints are composed of a strong cord portion with bony origin and insertion. The more palmarly placed accessory collateral ligaments originate from the proximal bone and insert into the palmar fibrocartilaginous plate. The palmar plates have strong distal attachments to resist extension forces. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
shortening of the lax collateral ligaments that may occur when these joints are immobilized in extension results in severe limitation of metacarpophalangeal joint flexion by these structures. The palmar fibrocartilaginous plate on the palmar side of the metacarpophalangeal joint is firmly attached
Collateral ligament (tight in flexion)
Figure 2-9 At the metacarpophalangeal joint level, the collateral ligaments are loose in extension but become tightened in flexion. The proximal membranous portion of the palmar plate moves proximally to accommodate for flexion. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Wynn Parry CB, et al. [1973]. Rehabilitation of the hand. London, Butterworth.)
to the base of the proximal phalanx and loosely attached to the anterior surface of the neck of the metacarpal by means of the joint capsule at the neck of the metacarpal. This arrangement allows the palmar plate to slide proximally during metacarpophalangeal joint flexion. The flexor tendons pass along a groove anterior to the plate. The palmar plates are connected by the transverse intermetacarpal ligaments, which connect each plate to its neighbor. The metacarpophalangeal joint of the thumb differs from the others in that the head of the first metacarpal is flatter and its cartilaginous surface does not extend as far laterally or posteriorly. Two small sesamoid bones are also adjacent to this joint, and the ligamentous structure differs somewhat. A few degrees of abduction and rotation are permitted by the ligament arrange-
Anatomy and Kinesiology of the Hand • 27 ment of the metacarpophalangeal joint at the thumb, which is of considerable functional importance in delicate precision functions. There is considerable variation in the range of motion present at the thumb metacarpophalangeal joints. The amount of motion varies from as little as 30° to as much as 90°. The digital interphalangeal joints are hinge joints (see Figure 2-7) and, like the metacarpophalangeal joints, have capsular and ligamentous enclosure. The articular surface of the proximal phalangeal head is convex in the anteroposterior plane with a depression in the middle between the two condyles, which articulates with the phalanx distal to it. The bases of the middle and distal phalanges appear as a concave surface with an elevated ridge dividing two concave depressions. A cord portion of the collateral ligament and an accessory collateral ligament are present, and the collateral ligaments run on each side of the joint from the dorsolateral aspect of the proximal phalanx in a palmar and lateral direction to insert into the distally placed phalanx and its fibrocartilage plate (Figure 2-10). A strong fibrocartilaginous (palmar) plate is also present, and the collateral ligaments of the proximal and distal interphalangeal joints are tightest with the joints in near full extension. The stability of the proximal interphalangeal joint is ensured by a three-sided supporting cradle produced by the junction of the palmar plate with the base of the middle phalanx and the accessory collateral ligament structures (see Figure 2-10). The confluence of ligaments is strongly anchored by proximal and lateral extensions called the checkrein ligaments. This system
Cord
Collateral ligament
Accessory Palmar plate Checkrein ligaments
Cord Accessory
Checkrein ligaments
Collateral ligament
Palmar plate
Figure 2-10 Strong, three-sided ligamentous support system of the proximal interphalangeal joint with cord and accessory collateral ligaments and the fibrocartilaginous plate, which is anchored proximally by the checkrein ligamentous attachment. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Eaton RG [1971]. Joint injuries of the hand. Springfield, IL, Charles C Thomas.)
has been described as a three-dimensional hinge that results in remarkable palmar and lateral restraint. A wide range of pathologic conditions may result from the interruption of the supportive ligament system of the intercarpal or digital joints. At the wrist level, interruption of key radiocarpal or intercarpal ligaments may result in occult patterns of wrist instability that are often difficult to diagnose and treat. In the digits, disruption of the collateral ligaments or the fibrocartilaginous palmar plates produces joint laxity or deformity, which is more obvious.
M USCLES AND TENDONS The muscles acting on the hand can be grouped as extrinsic, when their muscle bellies are in the forearm, or intrinsic, when the muscles originate distal to the wrist joint. It is essential to thoroughly understand both systems. Although their contributions to hand function are distinctly different, the integrated function of both systems is important to the satisfactory performance of the hand in a wide variety of tasks. A schematic representation of the origin and insertion of the extrinsic flexor and extensor muscle tendon units of the hand is provided in Figures 2-11 and 2-15. The important nerve supply to each muscle group is reviewed in these figures and again when discussing the nerve supply to the upper extremity.
Extrinsic Muscles The extrinsic flexor muscles (see Figure 2-11) of the forearm form a prominent mass on the medial side of the upper part of the forearm: The most superficial group comprises the pronator teres, the flexor carpi radialis, the flexor carpi ulnaris, and the palmaris longus; the intermediate group the flexor digitorum superficialis; and the deep extrinsics the flexor digitorum profundus and the flexor pollicis longus. The pronator, palmaris, wrist flexors, and superficialis tendons arise from the area about the medial epicondyle, the ulnar collateral ligament of the elbow, and the medial aspect of the coronoid process. The flexor pollicis longus originates from the entire middle third of the palmar surface of the radius and the adjacent interosseous membrane, and the flexor digitorum profundus originates deep to the other muscles of the forearm from the proximal two-thirds of the ulna on the palmar and medial side. The deepest layer of the palmar forearm is completed distally by the pronator quadratus muscle. The flexor carpi radialis tendon inserts on the base of the second metacarpal, whereas the flexor carpi ulnaris inserts into both the pisiform and fifth metacarpal base. The superficialis tendons lie superficial to the profundus tendons as far as the digital bases, where they bifurcate and wrap around the profundi and rejoin over
28
Part I • Foundation of Hand Skills
Composite
Flexor digitorum superficialis Nerve: median Action: flexion of proximal interphalangeal and metacarpophalangeal joints
Superficial
Palmaris longus Nerve: median Action: tension of palmar fascia
Flexor carpi ulnaris Nerve: ulnar Action: flexion of wrist; ulnar deviation of hand
Flexor carpi radialis Nerve: median Action: flexion of wrist; radial deviation of hand
Flexor carpi ulnaris Palmaris longus Flexor carpi radialis
Pronator quadratus Nerve: median Action: forearm pronation
Pronator quadratus
Supinator Pronator teres
Supination
Pronation
Supinator Nerve: radial Action: forearm supination
Brachioradialis
Pronator teres Nerve: median Action: forearm pronation
Brachioradialis Nerve: radial Action: pronation or supination, depending on position of forearm
Figure 2-11 Extrinsic flexor muscles of the arm and hand. (Dark areas represent origins and insertions of muscles.) (From Fess EE, Gettle K, Philips CA, et al. (2005). Hand and upper extremity splinting. St Louis, Mosby. Modified from Marble HC [1960]. The hand, a manual and atlas for the general surgeon. Philadelphia, WB Saunders.)
Anatomy and Kinesiology of the Hand • 29
Flexor digitorum profundus Nerve: median—index and long ulnar—ring and small Action: flexion of distal interphalangeal, proximal interphalangeal, and metacarpophalangeal joints
Composite
Flexor pollicis longus Nerve: median Action: flexes interphalangeal and metacarpophalangeal joints of thumb
Deep
Figure 2-11—cont’d.
the distal half of the proximal phalanx as Camper’s chiasma (Figure 2-12). The superficialis tendon again splits for a dual insertion on the proximal half of the middle phalanges. The profundi continue through the superficialis decussation to insert on the base of FDP
FDS
FDP Camper's chiasma
FDS
Figure 2-12 Anatomy of the relationship among the flexor digitorum superficialis (FDS), flexor digitorum profundus (FDP), and the proximal portion of the flexor tendon sheath. The superficialis tendon divides and passes around the profundus tendon to reunite at Camper’s chiasma. The tendon once again divides before insertion on the base of the middle phalanx. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
the distal phalanx. The flexor pollicis longus inserts on the base of the distal phalanx of the thumb. At the wrist the nine long flexor tendons enter the carpal tunnel beneath the protective roof of the deep transverse carpal ligament in company with the median nerve. In this canal the common profundus tendon to the long, ring, and small fingers divides into the individual tendons that fan out distally and proceed toward the distal phalanges of these digits (Figure 2-13). At about the level of the distal palmar crease the paired profundus and superficialis tendons to the index, long, ring, and small fingers and the flexor pollicis longus to the thumb enter the individual flexor sheaths that house them throughout the remainder of their digital course. These sheaths with their predictable annular pulley arrangement (Figure 2-14) serve not only as a protective housing for the flexor tendons, but also provide a smooth gliding surface by virtue of their synovial lining and an efficient mechanism to hold the tendons close to the digital bone and joints. There is an increasing recognition that disruption of this valuable
30
Part I • Foundation of Hand Skills A-1
Flexor digitorum profundus
A-2
C-1 A-3 C-2 A-4
C-3
A-5
Digital flexor sheath
Flexor digitorum superficialis
Hypothenar muscles
Sheath of flexor pollicis longus Median nerve Thenar muscles
Ulnar artery Ulnar nerve
Transverse carpal ligament Radial artery
Figure 2-13 Flexor tendons in the palm and digits. Fibroosseous digital sheaths with their pulley arrangement are shown, as is a division of the superficialis tendon about the profundus in the proximal portion of the sheath. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
pulley system can produce substantial mechanical alterations in digital function, resulting in imbalance and deformity. Extension of the wrist and fingers is produced by the extrinsic extensor muscle tendon system, which consists of the two radial wrist extensors, the extensor carpi ulnaris, the extensor digitorum communis, extensor indicis proprius, and the extensor digiti quinti proprius (extensor digiti minimi) (Figure 2-15). These muscles originate in common from the lateral epicondyle and the lateral epicondylar ridge and from a small area posterior to the radial notch of the ulna. The brachioradialis originates from the epicondylar line proximal to the lateral epicondyle and, because it inserts on the distal radius, it does not truly contribute to wrist or digit motion. The extensor carpi radialis longus and brevis insert proximally on the bases of the second and third metacarpals, respectively, and the extensor carpi ulnaris inserts on the base of the fifth metacarpal. The long digital extensors terminate by insertions on the bases of the middle phalanges after receiving and giving fibers to the intrinsic tendons to form the lateral bands that are destined to insert on the bases of the distal phalanx. Digital extension, therefore results from a combination of the contribution of both the extrinsic and intrinsic extensor systems. The extensor pollicis longus
Figure 2-14 Components of the digital flexor sheath. The sturdy annular pulleys (A) are important biomechanically in guaranteeing the efficient digital motion by keeping the tendons closely applied to the phalanges. The thin pliable cruciate pulleys (C) permit the flexor sheath to be flexible while maintaining its integrity. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Doyle JR, Blythe W [1975]. American Academy of Orthopaedic Surgeons: Symposium on tendon surgery in the hand. St Louis, Mosby.)
and brevis tendons, together with the abductor pollicis longus, originate from the dorsal forearm and, by virtue of their respective insertions into the distal phalanx, proximal phalanx, and first metacarpal of the thumb, provide extension at all three levels. The extensor pollicis longus approaches the thumb obliquely around a small bony tubercle on the dorsal radius (Lister’s tubercle) and therefore functions not only as an extensor but as a strong secondary adductor of the thumb. The extensor indicis proprius also originates more distally than the extensor communis tendons from an area near the origin of the thumb extensor and long abductor. It lies on the ulnar aspect of the communis tendon to the index finger and inserts with it in the dorsal approaches of that digit. The extensor digiti quinti proprius arises near the lateral epicondyle to occupy a superficial position on the dorsum of the forearm with its paired tendons lying on the fifth metacarpal ulnar to the communis tendon to the fifth finger. It inserts into the extensor apparatus of that digit. At the wrist, the extensor tendons are divided into six dorsal compartments (Figure 2-16). The first compartment consists of the tendons of the abductor pollicis longus and extensor pollicis brevis and the second compartment houses the two radial wrist extensors, the extensor carpi radialis longus and brevis. The third compartment is composed of the tendon of the extensor pollicis longus and the fourth compartment allows passage of the four communis extensor tendons and the extensor indicis proprius tendon. The extensor
Anatomy and Kinesiology of the Hand • 31
Extensor carpi radialis longus and brevis Nerve: radial Action: extension of wrist and radial deviation of hand
Extensor indicis proprius Nerve: radial Action: extension of index finger
Extensor pollicis longus Nerve: radial Action: extension of interphalangeal joint and metacarpophalangeal joint of thumb
Extensor carpi ulnaris Nerve: radial Action: extension of wrist and ulnar deviation of hand
Composite
Extensor digitorum communis and extensor digiti quinti proprius Nerve: radial Action: extension of fingers
Figure 2-15 Extrinsic extensor muscles of the forearm and hand. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Marble HC [1960]. The hand, a manual and atlas for the general surgeon. Philadelphia, WB Saunders.) Continued
digiti quinti proprius travels through the fifth dorsal compartment and the sixth houses the extensor carpi ulnaris.
Intrinsic Muscles The important intrinsic musculature of the hand can be divided into muscles comprising the thenar eminence, those comprising the hypothenar eminence, and the remaining muscles between the two groups (Figure
2-17). The muscles of the thenar eminence consist of the abductor pollicis brevis, the flexor pollicis brevis, and the opponens pollicis, which originate in common from the transverse carpal ligament and the scaphoid and trapezium bones. The abductor brevis inserts into the radial side of the proximal phalanx and the radial wing tendon of the thumb, as does the flexor pollicis brevis, whereas the opponens inserts into the whole radial side of the first metacarpal.
32
Part I • Foundation of Hand Skills
Extensor pollicis brevis Nerve: radial Action: extension of metacarpophalangeal joint of thumb
Abductor pollicis longus Nerve: radial Action: abduction of thumb
Figure 2-15—cont’d.
First dorsal interosseous
Extensor digitorum communis
Extensor indicis proprius
Extensor digiti quinti proprius
Extensor pollicis brevis
Abductor digiti quinti Extensor pollicis longus
Extensor carpi ulnaris
Extensor carpi radialis longus and brevis
1 2 3
4
5 6
Abductor pollicis longus
2
3
4
5
1
Figure 2-16
6
Arrangement of the extensor tendons in the compartments of the wrist.
The flexor pollicis brevis has a superficial portion that is innervated by the median nerve and a deep portion that arises from the ulnar side of the first metacarpal and is often innervated by the ulnar nerve. The hypothenar eminence in a similar manner is made up of the abductor digiti quinti, the flexor digiti quinti brevis, and the opponens digiti quinti, which originate primarily from the pisiform bone and the pisohamate ligament and insert into the joint capsule of the fifth metacarpophalangeal joint, the ulnar side of the base of
the proximal phalanx of the fifth finger, and the ulnar border of the aponeurosis of this digit. The strong thenar musculature is responsible for the ability to position the thumb in opposition so that it may meet the adjacent digits for pinch and grasp functions, whereas the hypothenar group allows a similar but less pronounced rotation of the fifth metacarpal. Of the seven interosseous muscles, four are considered in the dorsal group (Figure 2-18, B) and three as palmar interossei (Figure 2-18, C). The four dorsal
Anatomy and Kinesiology of the Hand • 33
Abductor pollicis brevis Nerve: median Action: abduction of thumb
Flexor pollicis brevis Nerve: median—superficial ulnar—deep Action: flexion and rotation of thumb
Abductor digiti quinti Nerve: ulnar Action: abduction of small finger (flexion of proximal phalanx, extension of proximal and distal interphalangeal joints)
Opponens pollicis Nerve: median Action: rotation of first metacarpal toward palm
Adductor pollicis Nerve: ulnar Action: adduction of thumb
Flexor digiti quinti brevis Nerve: ulnar Action: flexion of proximal phalanx of small finger and forward rotation of fifth metacarpal
Figure 2-17 Intrinsic muscles of the hand. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Marble HC [1960]. The hand, a manual and atlas for the general surgeon. Philadelphia, WB Saunders.) Continued
interossei originate from the adjacent sides of the metacarpal bones and, because of their bipennate nature with two individual muscle bellies, have separate insertions into the tubercle and the lateral aspect of the proximal phalanges and into the extensor expansion. The more palmarly placed three palmar interossei
(Figure 2-18, C) have similar insertions and origins and are responsible for adducting the digits together, as opposed to the spreading or abducting function of the dorsal interossei. In addition, four lumbrical tendons (Figure 2-19, A) arising from the radial side of the palmar portion of the flexor digitorum profundus
34
Part I • Foundation of Hand Skills
Lumbricals Nerve: median—index and long ulnar—ring and small Action: supplements metacarpophalangeal flexion and extension of proximal and distal interphalangeal joints
Dorsal interossei
Composite
Dorsal interossei Nerve: ulnar Action: spread of index and ring fingers away from long finger
All interossei Nerve: ulnar Action: flexion of metacarpophalangeal joints and extension of proximal and distal interphalangeal joints
Palmar interossei
Palmar interossei Nerve: ulnar Action: adduction of index, ring, and fifth fingers toward long finger
Figure 2-17—cont’d.
tendons pass through their individual canals on the radial side of the digits to provide an additional contribution to the complex extensor assemblage of the digits. The arrangement of the extensor mechanism, including the transverse sagittal band fibers at the metacarpophalangeal joint and the components of the extensor hood mechanism that gain fibers from both the extrinsic and intrinsic tendons, can be seen in Figure 2-19, B, C. An oversimplification of the function of the intrinsic musculature in the digits would be that they provide strong flexion at the metacarpophalangeal joints and extension at the proximal and distal interphalangeal joints. The lumbrical tendons, by virtue of their origin from the flexor profundi and insertion into the digital extensor mechanism, function as a governor between the two systems, resulting in a loosening of the antagonistic profundus tendon during interphalangeal joint
extension. The interossei are further responsible for spreading and closing of the fingers and, together with the extrinsic flexor and extensor tendons, are invaluable to digital balance. A composite, well-integrated pattern of digital flexion and extension is reliant on the smooth performance of both systems; and a loss of intrinsic function results in severe deformity. Perhaps the most important intrinsic muscle, the adductor pollicis (Figure 2-18, A), originates from the third metacarpal and inserts on the ulnar side of the base of the proximal phalanx of the thumb and into the ulnar wing expansion of the extensor mechanism. This muscle, by virtue of its strong adducting influence on the thumb and its stabilizing effect on the first metacarpophalangeal joint, functions together with the first dorsal interosseous to provide strong pinch. The adductor pollicis, deep head of the flexor pollicis brevis, ulnar two lumbricals, and all interossei, as well as the
Anatomy and Kinesiology of the Hand • 35
Adductor pollicis Opponens digiti quinti
Abductor pollicis brevis
Flexor digiti quinti
Flexor pollicis brevis Transverse carpal ligament Opponens pollicis
Abductor digiti quinti
Flexor carpi ulnaris Pronator quadratus
A
4
3
2
Abductor digiti minimi
1
Dorsal interossei (1 to 4)
Ulnar nerve
Palmar interossei (1 to 3) 1
2
3
C
B Figure 2-18
Position and function of the intrinsic muscles of the hand.
hypothenar muscle group, are innervated by the ulnar nerve. Loss of ulnar nerve function has a profound influence on hand function.
Muscle Balance and Biomechanical Considerations When there is normal resting tone in the extrinsic and intrinsic muscle groups of the forearm and hand, the wrist and digital joints are maintained in a balanced position. With the forearm midway between pronation and supination, the wrist dorsiflexed, and the digits in moderate flexion, the hand is in the optimum position from which to function. It may be seen that muscles are usually arranged about joints in pairs so that each musculotendinous unit has at least one antagonistic muscle to balance the
involved joint. To a large extent the wrist is the key joint and has a strong influence on the long extrinsic muscle performance at the digital level. Maximal digital flexion strength is facilitated by dorsiflexion of the wrist, which lessens the effective amplitude of the antagonistic extensor tendons while maximizing the contractural force of the digital flexors. Conversely, a posture of wrist flexion markedly weakens grasping power. At the digital level, metacarpophalangeal joint flexion is a combination of extrinsic flexor power supplemented by the contribution of the intrinsic muscles, whereas proximal interphalangeal joint extension results from a combination of extrinsic extensor and intrinsic muscle power. At the distal interphalangeal joint the intrinsic muscles provide a majority of the
36
Part I • Foundation of Hand Skills Ulnar
Radial
Triangular ligament
Lateral band Slip of long extensor to lateral band
Dorsal extensor expansion
Sagittal bands Lumbrical muscle Long extensor tendon
Interosseous muscle
A Long extensor tendon Interosseous muscle
B
Sagittal bands
Dorsal extensor expansion Central slip of common extensor Lateral band
Flexor profundus tendon Lumbrical muscle Flexor digitorum superficialis
Long extensor tendon Sagittal bands Bony insertion of interosseous tendon on proximal phalanx
Interosseous muscle
Lumbrical muscle
Distal movement of extensor expansion during flexion
Lateral band
C Figure 2-19 A. Extensor mechanism of the digits. B, C. Distal movement of the extensor expansion with metacarpophalangeal joint flexion is shown.
Anatomy and Kinesiology of the Hand • 37 extensor power necessary to balance the antagonistic flexor digitorum profundus tendon. The distance that a tendon moves when its muscle contracts is defined as the amplitude of the tendon and has been measured in numerous studies. In actuality the effective amplitude of any muscle is limited by the motion permitted by the joint or joints on which its tendon acts. It has been suggested that the amplitude of wrist movers (flexor carpi ulnaris, flexor carpi radialis, extensor carpi radialis longus, extensor carpi radialis brevis, and extensor carpi ulnaris) is approximately 30 millimeters with the amplitude of finger extensors averaging 50 millimeters; the thumb flexor, 50 mm; and the finger flexors 70 millimeters (Figure 2-20). Although these amplitudes have been thought to be important considerations when deciding on appropriate tendon transfers, Brand (1974, 1999) has shown that the potential excursion of a given tendon such as the extensor carpi radialis longus may be considerably
0 mm
3 mm
16 mm
26 mm (S) 23 mm (P) 16 mm (S) 17 mm (P)
44 mm
55 mm
5 mm (P) 46 mm (S) 38 mm (P) 88 mm (S) 85 mm (P)
Figure 2-20 Excursion of the flexor and extensor tendons at various levels. The numbers on the dorsum of the extended finger represent the excursion in millimeters necessary at each level to bring all distal joints from full flexion into full extension. The numbers shown by arrows on the palmar aspect of the flexed digit represent the excursion in millimeters for the superficialis (S) and the profundus (P) necessary at each level to bring the finger from full extension to full flexion. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Verdan C [1979]. Tendon surgery of the hand. London, Churchill Livingstone.)
greater than the excursion that was necessary to produce full motion of the joints on which it acted in its original position. Efforts have been made to determine the power of individual forearm and hand muscles and a formula based on the physiologic cross section is generally accepted as the best method for determining this value. The number of fibers in cross section determines the absolute muscle power of a given muscle, whereas the force of muscle action times the distance or amplitude of a given muscle determines the work capacity of the muscle. Therefore a large extrinsic muscle with relatively long fibers such as the flexor digitorum profundus is found to be capable of much more work than is a muscle with shorter fibers such as a wrist extensor. Table 2-1 is an indicator of the work capacities of the various forearm muscles. It can be seen that the flexor digitorum profundus and superficialis have a significantly greater work capacity than do the remaining extrinsic muscles. The abductor pollicis longus, palmaris longus, extensor pollicis longus, extensor carpi radialis brevis, and flexor carpi radialis have less than one fourth the capacity of these muscles. Several mechanical considerations are important in understanding the effect of a muscle on a given joint. The moment arm of a particular muscle is the perpendicular distance between the muscle or its tendon and the axis of the joint. The greater the displacement of an unrestrained tendon from the joint on which it acts, the greater is the angulatory effect created by the increased length of the moment arm. Therefore a tendon positioned close to a given joint either by position of the joint or by a restraining pulley has a much shorter moment arm than a tendon that is allowed to displace away from the joint (Figure 2-21). In simplifying the biomechanics of musculotendinous function, Brand (1974, 1999) has emphasized that the “moment” of a given muscle is the power of the muscle to turn a joint on its axis. It is determined by multiplying the strength (tension) of the muscle by the length of the moment arm. Again, it can be seen that the distance of tendon displacement away from the joint is the critical factor and that it does not matter where the tendon insertion lies. The importance of the various anatomic restraints of the extrinsic musculotendinous units at the wrist and in the digits is magnified by these mechanical factors.
N ERVE SUPPLY In considering the nerve supply to the forearm, hand, and wrist, understand that these nerves are a direct continuation of the brachial plexus and that at least a working knowledge of the multiple ramifications of the
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Part I • Foundation of Hand Skills
Table 2-1
MA
Normal
Work capacity of muscles
Muscle
Mkg 0.8
Extensor carpi radialis longus
1.1
PTE
A-4 C-1 A-3 C-2 C-3 A-5 IAPD
A-1
M
A
Flexor carpi radialis
A
A-2
IAPD PTE
Extensor carpi radialis brevis
90
0.9
B 1.1
Abductor pollicis longus
0.1
Flexor pollicis longus
1.2
Flexor digitorum profundus
4.5
Flexor digitorum superficialis
4.8
Brachioradialis
1.9
Flexor carpi ulnaris
2.0
Pronator teres
1.2
Palmaris longus
0.1
Extensor pollicis longus
0.1
Extensor digitorum communis
1.7
Abnormal MA
Extensor carpi ulnaris
1 % 2 A-4 1 % 2 A-2 IAPD
PTE
M
A
C
PTE
From Von Lanz T, Wachsmuth W (1970). Praktische anatomie. In JH Boyes, editor: Bunnell’s surgery of the hand, 5th ed. Philadelphia, Lippincott.
plexus is necessary if one is to fully appreciate the more distal motor and sensory contributions of the nerves of the upper extremity. Injuries at either the spinal cord or plexus level or to the major peripheral nerves in the upper extremity result in a substantial functional impairment for which splinting may be necessary. The median, ulnar, and radial nerves, as well as the terminal course of the musculocutaneous, are responsible for the sensory and motor transmission to the forearm, wrist, and hand. The superficial sensory distribution is shared by the median, radial, and ulnar nerves in a fairly constant pattern (Figure 2-22). This chapter is concerned with the most frequent distribution of
IAPD 90
D Figure 2-21 Biomechanics of the finger flexor pulley system. A. The arrangement of the annular and cruciate pulleys of the flexor tendon sheath. A, B, Normal moment arm (MA), the intra-annular pulley distance (IAPD) between the A-2 and A-4 pulleys, and the profundus tendon excursion (PTE), which occurs within the intact digital fibroosseous canal as the proximal interphalangeal joint is flexed to 90°. Annular pulleys: A-1, A-2, A-3, A-4, and A-5; cruciate pulleys: C-I, C-2, C-3. C, D, Biomechanical alteration resulting from excision of the distal half of the A-2 pulley together with the C-1, A-3, C-2, and proximal portion of the A-4 pulley. The moment arm is increased, and a greater profundus tendon excursion is necessary to produce 90° of flexion because of the bowstringing that results from the loss of pulley support. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Strickland JW [1983]. Management of acute flexor tendon injuries. Orthopaedic Clinics of North America, vol 14. Philadelphia, WB Saunders.)
these nerves, although it is acknowledged that variations are common. The palmar side of the hand from the thumb to a line passed longitudinally from the tip of the ring finger to the wrist receives sensory innervation from the median nerve. The remainder of the palm, as well as the ulnar half of the ring finger and the entire small finger, receives sensory innervation from the ulnar nerve. On the dorsal side, the ulnar nerve distribution again includes the ulnar half of the dorsal hand and the ring and small fingers, whereas the radial side is supplied by the superficial branch of the radial nerve. Some inner-
Anatomy and Kinesiology of the Hand • 39
Median
Median
Median
Ulnar Radial
Radial Ulnar nerve
A
Median nerve
Superficial branch of radial nerve
B
Figure 2-22 Cutaneous distribution of the nerves of the hand. A. Palmar surface. B. Dorsal surface. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
vation to an area distal to the proximal interphalangeal joints is supplied by the palmar digital nerves originating from the median nerve. The area around the dorsum of the thumb over the metacarpophalangeal joint is frequently supplied by the end branches of the lateral antebrachial cutaneous nerve. The extrinsic and intrinsic musculature of the forearm and hand is supplied by the median, ulnar, and radial nerves (Figure 2-23). The long wrist and digital flexors, with the exception of the flexor carpi ulnaris and the profundi to the ring and small fingers, are all supplied by the median nerve. The pronators of the forearm and the muscles of the thenar eminence, with the exception of the deep head of the flexor pollicis brevis and the adductor pollicis, which are innervated by the ulnar nerve, are also supplied by the median nerve. All muscles of the hypothenar eminence, all interossei, the third and fourth lumbrical muscles, the deep head of the flexor pollicis brevis, the adductor pollicis brevis, as well as the flexor carpi ulnaris and the ulnar-most two profundi, are supplied by the ulnar nerve. The radial nerve supplies all long extensors of the hand and wrist, as well as the long abductor and short extensor of the thumb, the supinator, and the brachioradialis of the forearm. When considering sensibility, one should remember that the hand is an extremely important organ for the detection and transmission to the brain of information relating to the size, weight, texture, and temperature of objects with which it comes in contact. The types of cutaneous sensation have been defined as touch, pain, hot, and cold. Although most of the nervous tissue
in the skin is found in the dermal network, smaller branches course through the subcutaneous tissue following blood vessels. Several types of sensory receptors have been described, and in most areas of the hand there is an interweaving of nerve fibers that allows each area to receive nerve input from several sources. In addition, deep sensibility from nerve endings in muscles and tendons is important in the recognition of joint position. The high interruption of the median nerve above the elbow results in a paralysis of the flexor carpi radialis, the flexor digitorum superficialis, the flexor pollicis longus, the profundi to the index and long fingers, and the lumbricals to the index and long fingers. In addition, pronation is weakened as a result of the loss of innervation of both the pronator teres and quadratus muscles and, most importantly, the patient loses the ability to oppose the thumb because of paralysis of the median nerve-innervated thenar muscle group. A more distal interruption of the median nerve at the wrist level produces loss of opposition and both lesions result in a critical impairment of sensation in the important distribution of that nerve to the palmar aspect of the thumb, index, long, and radial half of the ring finger. High ulnar nerve interruption produces paralysis of the flexor carpi ulnaris, the flexor profundi and lumbricals to the ring and small fingers and, most importantly, the interossei, adductor pollicis brevis, and deep head of the flexor pollicis brevis. The resulting loss of the antagonistic flexion at the metacarpophalangeal joints of the ring and small fingers permits
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Part I • Foundation of Hand Skills
Proper palmar digital nerves
Common digital nerves Palmar nerves to thumb Motor (thenar) branch of median nerve Median nerve
A
Proper palmar digital nerves
Radial nerve lesions at or proximal to the elbow result in a complete wrist drop and inability to extend the fingers at the metacarpophalangeal joints. It should be remembered that paralysis of this nerve does not result in inability to extend the interphalangeal joints of either the thumb or digits because of the contribution to that function by the intrinsic muscles. The sensory deficit over the dorsoradial aspect of the wrist and hand resulting from radial nerve interruption is of much less significance than are lesions to nerves innervating the palmar side. Various combinations of paralyses involving more than one nerve of the upper extremity are frequently encountered; those of the median and ulnar nerve are the most common. High lesions of these two nerves produce paralyses of both the extrinsic and intrinsic muscle groups with total sensory loss over the palmar aspect of the hand. More distal combined median and ulnar lesions have their effect primarily on the intrinsic muscles, resulting in the most disabling deformities with metacarpophalangeal hyperextension, interphalangeal flexion, and thumb collapse. An inefficient pattern of digital flexion consisting of a slow distal-toproximal rolling grasp results from the loss of the integrated intrinsic participation.
SKIN AND SUBCUTANEOUS FASCIA Proper palmar digital nerve to fifth finger Common digital nerve to ring and small fingers
Motor (deep) branch of ulnar nerve
Ulnar nerve
B Figure 2-23 Distribution of the median (A) and ulnar (B) nerves in the palm. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
hyperextension at this level by the unopposed long extensor tendons, often resulting in a claw deformity. The loss of the strong adducting and stabilizing influence of the adductor pollicis combined with the paralysis of the first dorsal interosseous muscle results in profound weakness of pinch and produces a collapse deformity of the thumb, necessitating interphalangeal joint hyperflexion for pinch (Froment’s sign). More distal lesions of the ulnar nerve usually result in a greater degree of claw deformity because of the sparing of the profundi function of the ring and small fingers. Sensory loss after ulnar nerve interruption involves the palmar ring (ulnar half) and small fingers.
The palmar skin with its numerous small fibrous connections to the underlying palmar aponeurosis is a highly specialized, thickened structure with little mobility. Numerous small blood vessels pass through the underlying subcutaneous tissues into the dermis. In contrast, the dorsal skin and subcutaneous tissue are much looser with few anchoring fibers and a high degree of mobility. Most of the lymphatic drainage from the palmar aspect of the fingers, web areas, and hypothenar and thenar eminences flows in lymph channels on the dorsum of the hand. Clinical swelling, which frequently accompanies injury or infection, is usually a result of impaired lymph drainage. The central, triangularly shaped palmar aponeurosis (Figure 2-24) provides a semirigid barrier between the palmar skin and the important underlying neurovascular and tendon structures. It fuses medially and laterally with the deep fascia covering the hypothenar and thenar muscles, and fasciculi extending from this thick fascial barrier extend to the proximal phalanges to fuse with the tendon sheaths on the palmar, medial, and lateral aspects. In the distal palm, septa from this palmar fascia extend to the deep transverse metacarpal ligaments forming the sides of the annular fibrous canals, allowing for the passage of the ensheathed flexor tendons and the lumbrical muscles and the neurovascular bundles.
Anatomy and Kinesiology of the Hand • 41
Palmar aponeurosis (reflected)
Flexor digitorum superficialis
Sheath of flexor pollicis longus
Ulnar artery Ulnar nerve
Median nerve Thenar muscles
Transverse carpal ligament
As generally stated, power grip is a combination of strong thumb flexion and adduction with the powerful flexion of the ring and small fingers on the ulnar side of the hand. The radial half of the hand employing the delicate tripod of pinch among the thumb, index, and long fingers is responsible for more delicate precision function. An analysis of hand functions requires that one consider the thumb and the remainder of the hand as two separate parts. Rotation of the thumb into an opposing position is a requirement of almost any hand function, whether it is strong grasp or delicate pinch. The wide range of motion permitted at the carpometacarpal joint is extremely important in allowing the thumb to be correctly positioned. Stability at this joint is a requirement of almost all prehensile activities and is ensured by a unique ligamentous arrangement, which allows mobility in the midposition and provides stability at the extremes. As can be seen in Figure 2-25, the thumb moves through a wide arc from the side of
Figure 2-24 Palmar aponeurosis reflected distally reveals septa and underlying palmar anatomy.
Dorsally the deep fascia and extensor tendons fuse to form the roof for the dorsal subaponeurotic space, which, although not as thick as its palmar counterpart, may prove restrictive to underlying fluid accumulations or intrinsic muscle swelling.
FUNCTIONAL PATTERNS The prehensile function of the hand depends on the integrity of the kinetic chain of bones and joints extending from the wrist to the distal phalanges. Interruptions of the transverse and longitudinal arch systems formed by these structures always result in instability, deformity, or functional loss at a more proximal or distal level. Similarly, the balanced synergism–antagonism relationship between the long extrinsic muscles and the intrinsic muscles is a requisite for the composite functions necessary for both power and precision functions of the hand. It is essential to recognize that the hand cannot function well without normal sensory input from all areas. Many attempts have been made to classify the different patterns of hand function, and various types of grasp and pinch have been described. Perhaps the more simplified analysis of power grasp and precision handling as proposed by Napier (1955, 1956) and refined by Flatt (1979, 1983, 1995) is the easiest to consider.
Figure 2-25 Progressive alterations in precision grasp with changes in object size. Adaptation takes place primarily at the carpometacarpal joint of the thumb and the metacarpophalangeal joints of the digits. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
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Part I • Foundation of Hand Skills
the index finger tip to the tip of the small finger, and the adaptation that occurs between the thumb and digits as progressively smaller objects are held occurs primarily at the metacarpophalangeal joints of the digits and the carpometacarpal joint of the thumb. For power grip the wrist is in an extended position that allows the extrinsic digital flexors to press the object firmly against the palm while the thumb is closed tightly around the object. The thumb, ring, and small fingers are the most important participants in this strong grasp function, and the importance of the ulnar border digits cannot be minimized (Figure 2-26). In precision grasp, wrist position is less important, and the thumb is opposed to the semiflexed fingers with the intrinsic tendons providing most of the finger movement. When the intrinsic muscles are paralyzed, the balance of each finger is markedly disturbed. The metacarpophalangeal joint loses its primary flexors, and the interphalangeal joints lose the intrinsic contribution to extension. A dyskinetic finger flexion results in which the metacarpophalangeal joints lag behind the interphalangeal joints in flexion. When the hand is closed on an object, only the fingertips make contact rather than the uniform contact of the fingers, palm, and thumb that occurs with normal grip (Figure 2-27). Certain activities may require combinations of power and precision grips, as seen in Figure 2-28. Pinching between the thumb and either the index or long finger is a further refinement of precision grip and may be classified as tip grip, palmar grip, or lateral grip (Figure 2-29), depending on the portions of the phalanges brought to bear on the object being handled. In these functions the strong contracture of the adductor pollicis brings the thumb into contact against the tip or sides of the index or index and long fingers with digital
Figure 2-26 Strong power grip imparted primarily by the thumb, ring, and small fingers around the hammer handle with delicate precision tip grip employed to hold the nail. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
A
B Figure 2-27 A. Normal hand grasping a cylinder. Uniform areas of palm and digital contact are shaded. B. Intrinsic minus (claw hand grasping the same cylinder). The area of contact is limited to the fingertips and the metacarpal heads. (From Brand PW [1999]. Clinical mechanics of the hand, 2nd ed. St Louis, Mosby.)
resistance imparted by the first and second dorsal interossei. The size of the object being handled dictates whether large thumb and digital surfaces, as in palmar grip, or smaller surfaces, as in lateral or tip grasp, are used. Flatt (1972) has pointed out that the dual importance of rotation and flexion of the thumb is often ignored in the preparation of splints, which permit only tip grip because the thumb cannot oppose the pulp of the fingers to produce palmar grip. The patterns of action of the normal hand depend on the mobility of the skeletal arches, and alterations of the configuration of these arches are produced by the balanced function of the extrinsic and intrinsic muscles. Whereas the extrinsic contribution resulting from the large powerful forearm muscle groups is more important to hand strength, the fine precision action imparted by the intrinsic musculature gives the hand an enormous variety of capabilities. Although one need
Anatomy and Kinesiology of the Hand • 43 original unabridged work may be found in Fess EE, Gettle KS, Philips CA, Janson JR (2005). Hand and upper extremity splinting: Principles and methods, 3rd ed. St Louis, Mosby.
REFERENCES
Figure 2-28 Power grip used to hold the squeeze bottle with precision handling of the bottle top by the opposite hand. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby.)
A
B
C
Figure 2-29 Types of precision grip. A. Tip grip. B. Palmar grip. C. Lateral grip. (From Fess EE, Gettle K, Philips CA, et al. [2005]. Hand and upper extremity splinting. St Louis, Mosby. Modified from Flatt AE [1974]. The care of the rheumatoid hand, 3rd ed. St Louis, Mosby.)
not specifically memorize the various patterns of pinch, grasp, and combined hand functions, it is essential to understand the underlying contribution of the various muscle-tendon groups, both extrinsic and intrinsic, to these activities.
ACKNOWLEDGMENTS I am extremely grateful to Gary W. Schnitz for many of the excellent illustrations used in this chapter. This chapter has been edited by Elaine Ewing Fess, MS, OTR, FAOTA, CHT for inclusion in this book. The
Arey L (1980). Developmental anatomy, 7th ed. Philadelphia, WB Saunders. Basmajian JU (1980). Electromyography—dynamic gross anatomy: A review. American Journal of Anatomy, 159:245–260. Bell-Krotoski J (1990). Light touch-deep pressure testing using Semmes-Weinstein monofilaments. In J Hunter, L Schneider, E Mackin, A Callahan, editors. Rehabilitation of the hand, 3rd ed. St Louis, Mosby. Blumfield RH, Champoux JA (1984). A biomechanical study of normal functional wrist motion. Clinical Orthopedics, 187:23–25. Bora FW (1986). The pediatric upper extremity. Philadelphia, WB Saunders. Brand PW (1974). Biomechanics of tendon transfer. Orthopedic Clinics of North America 5:202–230. Brand PW, Hollister A (1999). Clinical mechanics of the hand, 3rd ed. St Louis, Mosby. Bunnell S (1944). Surgery of the hand. Philadelphia, JB Lippincott. Cooney W, Linscheid R, Dobyns J (1998). The wrist diagnosis and operative treatment. St Louis, Mosby. Flatt AE (1972). Restoration of rheumatoid finger joint function. III. Journal of Bone & Joint Surgery, 54A:1317–1322. Flatt AE (1979). The care of minor hand injuries. St Louis, Mosby. Flatt AE (1983). Care of the arthritic hand. St Louis, Mosby. Flatt AE (1995). The care of the arthritic hand, 5th ed. St Louis: Quality Medical Publishing. Lichtman D, Alexander A (1988). The wrist and its disorders. Philadelphia, WB Saunders. Long C, Conrad MS, Hall EA, Furler MS (1970). Intrinsicextrinsic muscle control of the hand in power grip and precision handling. Journal of Bone & Joint Surgery, 52A:853–867. Moberg E (1958). Objective methods of determining the functional value of sensibility of the hand. Journal of Bone & Joint Surgery, 40B:454–476. Moore KL (1982). The developing human: Clinically oriented embryology, 3rd ed. Philadelphia, WB Saunders. Napier J (1955). The form and function of the carpometacarpal joint of the thumb. Journal of Anatomy, 89:362. Napier JR (1956). The prehensile movements of the human hand. Journal of Bone & Joint Surgery, 38B:902–913. Taleisnik J (1976a). Wrist anatomy, function, and injury. American Academy of Orthopedic Surgeons’ Instructional Course Lectures, vol. 27. St Louis, Mosby. Taleisnik J (1976b). The ligaments of the wrist. Journal of Hand Surgery [America] 1:110–118. Taleisnik J (1985a). The wrist. New York, Churchill Livingstone. Taleisnik J (1985b). Carpal kinematics. In The wrist. New York, Churchill Livingstone.
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Taleisnik J (1992). Soft tissue injuries of the wrist. In JW Strickland, AR Rettig, editors: Hand injuries in athletes. Philadelphia, WB Saunders. Weber ER (1982). Concepts governing the rotational shift of the intercalated segment of the carpus. Orthopedic Clinics of North America, 15:193–207. Weber ER (1988). Physiologic bases for wrist function. In D Lichtman, A Alexander, editors: The wrist and its disorders. Philadelphia, WB Saunders.
SUGGESTED READINGS Chase RA (1973). Atlas of hand surgery. Philadelphia, WB Saunders. Chase RA (1984). Atlas of hand surgery, vol. 2. Philadelphia, WB Saunders. Clemente CD (editor) (1990). Gray’s anatomy of the human body, 14th ed. Philadelphia, Lea & Febiger. Hollingshead HW (editor) (1982). Anatomy for surgeons, vol 4. The back and limbs. New York, Harper & Row.
Kaplan EB (1965). Functional and surgical anatomy of the hand, 2nd ed. Philadelphia, JB Lippincott. Landsmere J (1976). Atlas of anatomy of the hand. Edinburgh, Churchill Livingstone. Mackin E, Callahan A, Skirven TM, Schneider L, Osterman AL (editors) (2002). Hunter, Mackin, & Callahan’s rehabilitation of the hand and upper extremity, 5th ed. St Louis, Mosby. Matsen FA, Fu FH, Hawkins RJ (1993). The shoulder: A balance of mobility and stability, Rosemont, IL, American Academy of Orthopedic Surgeons. Morrey BF (2000). The elbow and its disorders, 3rd ed. Philadelphia, WB Saunders. Rasch P, Burke R (1990). Kinesiology and applied anatomy, 9th ed. Philadelphia, Lea & Febiger. Rockwood CA, Matsen FA, Wirth MA, Lippitt SB (editors) (2004). The shoulder, 3rd ed. Philadelphia, WB Saunders. Zancolli E (1968). Structural and dynamic basis of hand surgery. Philadelphia, JB Lippincott.
Chapter
3
NORMAL AND IMPAIRED DEVELOPMENT OF FORCE CONTROL IN PRECISION GRIP Ann-Christin Eliasson
CHAPTER OUTLINE DEVELOPMENT OF MOVEMENT CONTROL THEORIES LEARNED MOVEMENTS AFFERENT INFORMATION Proprioception Touch BASIC COORDINATION OF FORCES DURING GRASPING Development of Manipulatory Forces DEVELOPMENT OF ANTICIPATORY CONTROL Weight Size Friction ORGANIZATION OF SENSORIMOTOR CONTROL IMPAIRED FORCE CONTROL AND CLINICAL IMPLICATIONS Force Coordination Anticipation of the Properties of Objects Sensory Information Used for Force Control SUMMARY
The hand is an effective tool that is used in many different tasks of daily life. The successful performance of manual skills in daily life depends on a complex process incorporating several different aspects of a person’s capability (Figure 3-1). The usefulness of the hand is highly dependent on cognition because one has to understand the value of using one’s hands for a
meaningful purpose. Then the task to be performed has to be encoded and translated into purposeful actions, and these must be performed in the appropriate order. In the last decade, considerable attention has been given to the development of prehensile force control during the manipulation of objects in both healthy children and children with cerebral palsy (CP), as well as attention deficit hyperactivity disorder (ADHD) and other kinds of dysfunctions related to the central nervous system (CNS). It is known that integration of somatosensory information is crucial for the fine tuning of motor commands, force regulation, and the build up of memory strategies for grasping and manipulating objects. Coordination of movements and somatosensory control develop rapidly during the first years of life. The refinement continues for many years, and adult-like sensorimotor control is not attained until the early teenage years. If somatosensory control is dysfunctional, a person is observed to be clumsy to a greater or lesser degree. Furthermore, people’s perceptions have an effect on their performance of manual skills because their sensory impressions should be translated into meaningful information even for the very simplest of tasks. The perceptual system provides information about the position of the hand in space, as well as the position of the target, both of which are important for goal-directed movement. Finally, the musculoskeletal components are crucial for motor output. Although any movement a person brings about is highly dependent on how the CNS plans and organizes the movement, the contractile components of the muscles, bones, and joints are the effectors of the planned movement. Another cognitive aspect is motivation, which is closely related to attention and concentration, and all of which have an influence on the successful performance of manual skills. A reduced focus on a task almost certainly limits the ability to learn. Thus self-efficacy
45
46
Part I • Foundation of Hand Skills Motivation
Sensorimotor system
Cognition Task-comprehension
Perception
Attention Task-focus Hand use
Muscles and skeletal system Self-efficacy
Figure 3-1 Descriptive illustration of components influencing children’s ability to use their hands. (From Eliasson AC (2004). Improving the use of the hands in daily activities: aspects of the treatment of children with cerebral palsy. Physical and Occupational Therapy in Pediatrics, 25:37–60.)
and body image have an impact on one’s ability to perform tasks. Although the performance of manual skills is complex, this chapter discusses how the sensory information received about an object is increasingly well integrated with motor processing during development, leading to smooth, coordinated movements of the hand. This chapter also describes how impairment, mainly arising from CP, but also from dysfunctions such as those seen in children with ADHD and developmental coordination disorder (DCD) affects sensorimotor control of the hand. Dysfunction or impairment of the CNS almost always affects hand function. There is a continuum of decreasing hand function from being somewhat clumsy to having severe impairment. It seems that the diagnosis is less important; it is the grade of impairment or dysfunction that is crucial. Children with CP have different degrees of impaired hand function. Some children only have difficulty performing differentiated finger movements or in-hand manipulation, whereas others have severe impairments that make it impossible even to grasp an object. Most children with ADHD have fairly good hand function, but when DCD is present also, the clumsiness is more apparent. Regardless of the degree of severity, decreased hand function has an impact on children’s daily self-care or school activities, and it affects their engagement in play or leisure. The ability to analyze a child’s capacity to use his or her hands and compare the child’s capabilities with the complexity of the task is a prerequisite for intervention planning. This chapter explains the underlying causes of the impairment or clumsiness apparent in children with impairment or dysfunction in their CNS. By understanding the mechanisms normally responsible for controlling movements, intervention that takes into consideration the mechanism controlling manual skills can be planned. Some examples of this are given later in this chapter.
DEVELOPMENT OF MOVEMENT CONTROL THEORIES At the beginning of this century, sensory stimuli were thought to be responsible for the generation of movements. This concept was based on studies by Mott and Sherrington (1895) on deafferented monkeys. By transecting the dorsal roots, researchers cut sensory fibers and left the motor fibers intact. The complete sensory loss resulted in permanent abolishment of almost all voluntary movements, especially in the distal segments. A model was proposed in which the movements were generated by chain reflexes; the sensory information from the first muscle contraction elicited the subsequent spinal reflex. This reflex origin of movement was disputed by Brown (1911), who studied locomotion in spinal cats. He suggested instead a central origin in which neuronal networks could generate basic locomotor activity in the absence of sensory information (half center model). The task of the afferents was restricted to modifying and compensating for ongoing movements. However, it took quite a long time before this idea was confirmed. Nowadays there are several elegant studies that indicate that innate neural networks control rhythmic motor behavior in a variety of species such as locusts, lampreys, and cats (Forssberg, Grillner, & Halbertsma, 1980; Forssberg et al., 1980; Grillner, Wallen, & Brodin, 1991; Wilson, 1964). Neural networks, called central pattern generators (CPGs), consist of a group of interneurons that interact in an organized manner to produce a motor act. Detailed knowledge of how one CPG operates has been demonstrated in the lamprey, a primitive vertebrate fish. The lamprey is especially suited for such studies because the spinal cord survives in vitro for several days, and neurons involved in the locomotor network for swimming are visible under the micro-
Normal and Impaired Development of Force Control in Precision Grip • 47 scope, which facilitates microelectrode recording. The swimming can be initiated by stimulation of specific areas in the brainstem, sensory stimuli if some skin areas are left innervated, and bath-applied excitatory amino acids. Information about the networks also has been used for computer simulation (Grillner et al., 1991). The central origin of motor behavior has been further demonstrated in other rhythmic movements, such as mastication, swallowing, and respiration (Feldman & Grillner, 1983; Lund & Olsson, 1983; Miller, 1972). Swallowing occurs after the denervation of muscles activated early in the sequence, indicating that the brain sets the motor program for the whole motor act in advance. However, this does not diminish the importance of afferent signals for modulation and learning of movements. Movements are activated by efferent signals from several higher levels of the CNS, which are modulated by afferent signals from the sensory system and by visual, auditory, and somatosensory information. There are many reasons to believe that the human nervous system is organized in the same way. Spontaneous movements in the human fetus appear from the eighth gestational week, just after the first functional synapses between neurons are developed. The movements seem to be generated by neural networks, and the afferents may not be needed for initiating the movements but are used mainly to adjust and compensate for disturbances (de Vries, Visser, & Pechtl, 1982; Okado, 1980, 1981). Innate motor programs, such as breathing, sucking, and swallowing, function at birth. The complex pattern of infant stepping also is innate, but this program is immature in the newborn and cannot be used for independent walking until the child has learned to control and adjust the patterns to external conditions. The system develops both through practice and by the process of maturation, in which connections with higher central and afferent sensory input continue to be established. This is the concept from which new therapeutic approaches are developed.
LEARNED MOVEMENTS Voluntary movements in humans are complex. It is difficult to demonstrate a simple fixed pattern from a CPG, although skilled movements appear to depend on a set of motor programs. According to Brooks (1986), “Motor programs are a set of muscle commands that are structured before the motor acts begin and that can be sent to the muscles with the correct timing so that the entire sequence can be carried out in the absence of peripheral feedback” (p. 7),
or, in other words, can follow an initial plan. In welllearned, fast movements the trajectory exactly follows this initial plan. The initiation and termination are
planned together, and the movements are almost impossible to stop until completed. This is true, for example, when throwing a ball and in more complex actions, such as typing. Even continuous movements of moderate speed, such as handling well-known objects, are programmed but allow some amount of sensory feedback. Both kinds of movements are called anticipatory or feed-forward controlled movements, with the characteristic bell-shaped, single-peaked velocity profile (see later discussions). Slow movements generally are not programmed, allowing time for correction of the ongoing movement by afferent signals, and demonstrated by a discontinuous velocity profile (Brooks, 1986). The motor programs are learned by practice when the afferent information adjusts the ongoing movement and updates the motor program for the final movement. The importance of sensory information is demonstrated by birdsong learning in the European chaffinch. Normally, the young birds are exposed to singing by their mothers but do not start singing themselves until 10 months of age. If the birds are not exposed to the adult song, they produce only rudimentary sequences. If the birds are exposed to adult song during the first 4 months of life and then isolated from songs during the month after, they start to sing properly. This indicates that auditory experience is necessary for the motor program to be fully developed. If the birds are deafened after 4 months but before they start to sing, they sing in a very awkward way. Deafening after they start to sing, however, does not affect the song. This indicates that birds also must compare the initial motor program for singing with the actual song, that is, afferent information also is necessary to be able to learn to use the program of singing. The afferent information corrects the song and updates the program, which could be used without afferent feedback when the song was established (Konishi, 1965; Nottebohm, 1970).
AFFERENT INFORMATION The importance of afferent information is seen in patients with large sensory fiber neuropathies, in which the large afferent fibers generating proprioceptive and tactile information degenerate. Unless these patients see their limbs, they do not know their position and cannot detect limb motion. When reaching toward a target without seeing the moving hand, they make large errors; if they look at the hand before reaching, the hand comes closer to the target. This indicates that these patients can compensate for the lack of somatosensory information visually and also use vision to program the reaching in advance. Because the patients cannot stop the movement precisely at the desired
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target, information from various receptors in the skin is essential for precise movements (Ghez et al., 1990). Impaired sensation is also common in children with hemiplegic CP and has to be taken into account when planning treatment.
PROPRIOCEPTION The proprioceptive system gives information about the stationary position of the limbs (limb position sense) and movements of the limb (kinesthesia). The latter information is mediated from tendon organs and muscle spindles and also from receptors in the skin, sensitive to skin stretch. The tendon organ signals information about the strength of muscle contraction, increased signaling indicating increased tension. Signals from the muscle spindle regulate the length of the muscle fibers. The receptors are rather complicated and, despite intensive research, their function is not fully understood. It has been agreed, however, that the muscle spindle is responsible for small changes in muscle contraction, which may be important for force regulation during the grasping act. There are muscle spindles in almost all skeletal muscles, and they mediate information mainly through 1a afferents to the spinal cord. The muscle spindle also has efferent innervation to intrafusal muscle fibers, in which the primary and secondary endings set the sensitivity to the afferent signals. The different contractions of intrafusal muscle fibers are probably crucial for the information sent to the CNS. Alpha and gamma motor neurons are co-activated by central mechanisms to maintain the sensitivity of the muscle spindles throughout the range of almost all movements. There have been different models for the coactivation of alpha and gamma motor neurons, but it appears that descending commands activate both, as demonstrated by Vallbo (1970) in studies of microneurography. The afferent signals are used to update and correct the motor programs, and the information can be used in a conscious way to give knowledge about the limb movement and position in space.
TOUCH The tactile system is used to discriminate between different surfaces and shapes and also provides sensory input to the CNS, which regulates the force of the muscles during grasping and holding of objects. Touch transmits nerve impulses from mechanoreceptors to the CNS via axons with different diameters. Large fibers with a fast conduction rate mediate tactile sensation from the skin, whereas thin fibers with a slow conduction rate mediate sensation of pain and temperature. The receptors mediating tactile sensation can be classified on the basis of their receptive fields and
morphology: Two receptor types, Meissner and Pacini corpuscles, are fast adapting; Meissner corpuscles have small, sharply delineated sensory fields; and Pacini corpuscles have large and diffuse sensory fields. Two other types of receptors that are slow-adapting units are Merkel corpuscles, with small and sharply delineated sensory fields, and Ruffini corpuscles, with large and diffuse fields. Mechanoreceptors with small receptive fields are suitable for fine spatial discrimination because they have a high sensitivity over the entire field, whereas mechanoreceptors with large receptive fields have a central area of high sensitivity and decreased sensitivity in the border of the receptive field. Because there are about 17,000 tactile units in the hand and approximately 70% of them have small receptive fields, it can be postulated that the tactile system of the hand is highly developed to detect small movements and discriminate among different surfaces (Johansson & Vallbo, 1983). People explore the surface of an object by manipulation of the fingers. The difference between exploring known and unknown surfaces is the speed of the finger movements (Roland, Ericsson, & Widen, 1989). A relevant movement for exploring the different surfaces of an object is by touch through digital manipulation, whereas a more adequate way to explore the shape is by rotation of the wrist and bimanual hand activity. The fingertips are very sensitive to tactile information, and tactile discrimination occurs early during development. One-year-old children can recognize dissimilar objects, and they are able to use the two different exploratory maneuvers for objects differing in texture or shape (Ruff, 1984). Newborn monkeys can distinguish different textures by choosing the texture that gives milk (Carlson, 1984). These examples indicate that, despite an immature nervous system, there is early interaction between somatosensory signals and motor output.
BASIC COORDINATION OF FORCES DURING GRASPING During the last decade Johansson and Westling (1984, 1987, 1988, 1990) have studied grasping movement to understand how somatosensory information is integrated with motor control. In adults, movements of the hand and fingers are precise and the forces of the fingers well controlled. This is not an innate behavior; in fact, these functions develop during early childhood and may be dysfunctional if there is impairment in the CNS (Eliasson & Gordon, 2000; Eliasson, Gordon, & Forssberg, 1991, 1992, 1995; Forssberg et al., 1991, 1992, 1995, 1999; Gordon et al., 1992).
Normal and Impaired Development of Force Control in Precision Grip • 49 Most grasping acts involve lifting and holding objects, grasping with the fingers, and lifting with the arm. The object seen in Figures 3-2 and 3-3 measures grip force from each grip surface (thumb and index finger), a combined vertical load force by strain-gauge transducers, and vertical movement by a photoresistor (Eliasson et al., 1991). With this instrument it has been possible to define different phases of the lift and under-
Figure 3-2
stand how they are linked to produce smooth movements. When grasping the instrument, there is a short delay before the vertical load force starts to increase. This preload phase is important for establishment of the grasp. During the loading phase the grip and load forces increase in parallel until the instrument starts to move. The rates of grip and load forces have mainly bell-shaped profiles (see later discussion) adjusted to
Child lifting the experimental object.
Figure 3-3 Experimental instrument in which the grip surfaces are exchangeable and the weight can be covaried without any visual changes.
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the weight, size, and frictional character of the surface of the object. After the loading phase there is a transition phase, in which the lift reaches the final position and the forces are well adjusted to the current properties of the object. In the final static phase the object is held in the air (Figure 3-4). Tactile information triggers different motor commands and links the different phases together. The different types of receptors respond differently during the lift, which has been demonstrated by microneurography from single tactile units innervating the glabrous skin of the fingers. Fast-adapting receptors send bursts of impulses when first touching an object,
1 Year
at the beginning of the loading phase and at lift-off but are silent during the static phase. Slow-adapting receptors send impulses continuously during the static phase (Johansson & Vallbo, 1983). This ability makes it possible to handle small fragile objects without crushing them. To investigate how separate components affect the grasping act, the object has a slot in which blocks of different weights may be inserted while the visual appearance remains constant; the contact pads can be covered with silk or sandpaper, each having different frictional character, and the size can be adjusted by boxes of different size attached to the instrument (see Figure 3-3).
6 Years
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Figure 3-4 Superimposed traces of representative lifts performed at different ages and in three children with cerebral palsy with various degree of severity. Grip force, load force, position, and grip force rate are shown as functions of time. When lifting the object, the grip force starts to increase; then the grip force and load force increase until the object starts to move. When the forces overcome gravity, the signal measuring position increases, followed by a static phase when the object is held in the air. (Modified from Forssberg H, Eliasson AC, Kinoshita H, Johansson RS, Westling G [1991]. Development of human precision grip. I. Basic coordination of force. Experimental Brain Research, 85:451–457; Forssberg H, Eliasson AC, Redon-Zouiteni C, Mercuri C, Dubowitz L [1999]. Impaired grip-lift synergy in children with unilateral brain lesions. Brain, 122:1157–1168.)
Normal and Impaired Development of Force Control in Precision Grip • 51
DEVELOPMENT OF MANIPULATORY FORCES During the loading phase, just before the movement starts, the grip and load forces are generated in parallel for coordinated movements. This parallel increment of both grip and load force increases with heavier objects, resulting in prolonged latency until lift-off. If the contact surface changes, the grip force increases more for slippery materials compared with rough materials, whereas the load force remains the same. Still the forces increase in parallel but with different slope. This parallel force generation forms a lifting synergy to simplify movements (Bernstein, 1967). It develops from the second year when the pincer grasp is fully developed. Smaller children cannot generate grip and load forces in parallel; they initiate forces sequentially. This is clearly seen in Figure 3-5; most of the grip force increases before the onset of load force. The force rate profile is irregular and has several peaks in young children, whereas older children and adults perform mainly a bell-shaped force rate profile, adjusted to the
weight of the object at lift-off, indicating anticipatory controlled movements (Brooks, 1986; Forssberg et al., 1991). Small children also have more variation than adults because they cannot repeatedly produce similar movements. However, 1-year-old children can use tactile and proprioceptive information to adjust the forces by sensory feedback during the static phase. All phases are prolonged, and the different phases are not triggered elegantly as in adults (Forssberg et al., 1995). There is an increased difference between thumb and finger contact, probably because of an immature ability to adjust the finger toward the object’s size (von Hofsten & Ronnquist, 1988). This uncoordinated movement in small children is likely attributable to immature motor output and sensory processing. There is rapid development until age 2. The refined coordination then progressively develops until leveling out at ages 4 to 6 and continues gradually until the teenage years, when the lifts are completely adult-like (see Figure 3-4) (Forssberg et al., 1991).
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Figure 3-5 Grip force during the preload and the loading phase (before lift-off) is plotted against load force in children of different ages and children with cerebral palsy. Trials are superimposed for each subject. (Modified from Forssberg H, Eliasson AC, Kinoshita, H, Johansson RS, Westling G [1991]. Development of human precision grip. I. Basic coordination of force. Experimental Brain Research, 85:451–457; Eliasson AC, Gordon AM, Forssberg H [1991]. Basic coordination of manipulative forces in children with cerebral palsy. Developmental Medicine and Child Neurology, 33:661–670.)
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DEVELOPMENT OF ANTICIPATORY CONTROL Peak Grip Force Rate (N/s)
100
SIZE Anticipatory control also is predicted from visual information about an object’s size (Gordon et al., 1991a,b). When the object is kept proportional to the volume,
60 40 20
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WEIGHT When the weight of the object is varied but the visual appearance remains constant, adults typically scale the grip and load force rates based on earlier experience of the object’s weight. This is indicated by higher grip and load force rates for heavier objects. The forces are decreased at lift-off to harmonize with the weight of the object. The anticipatory mechanism can be further demonstrated when lifting an unexpectedly light object. For example, if one lifts an unopened but empty can of soda, the lift will probably be too high because a heavier can is expected. However, this occurs only once for the same can. Somatosensory information adjusts the forces to the object’s actual weight during the static phase and updates the internal representation of the object for a smooth movement the next time the object is lifted. Children cannot handle this type of situation as efficiently as adults. However, despite uncoordinated force generation and large variation of grip and load force rates, 2-year-old children start to scale the forces toward different weights. It takes several years until the anticipatory control of weight is fully developed. Children between the ages of 6 and 8 are nearly adultlike although the variation is still larger than in adults (Figure 3-6). This indicates that anticipatory scaling of forces occurs in conjunction with maturation of coordinated movement (Forssberg et al., 1992).
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Anticipatory control of manipulation apparently requires the nervous system to efficiently use sensory information to integrate and store information for internal representation or memory representation of an object. This internal representation is necessary to produce rapid and well-coordinated transitions between the various movement phases because of a long delay between motor command and sensory feedback. This is true for reaching, grasping, and lifting movements, as well as for movement involving the whole body. In the lifting task the motor output is based on internal representation of the object’s properties learned by prior experience of the weight, friction, size, and haptic cues of the object (Gordon et al., 1991a,b; Johansson & Westling, 1990).
200 800
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Figure 3-6 Influence of the 200- and 800-g weight (400 g for 1- to 2-year-old children) in the constant lifting series for peak grip force rate (A) and peak acceleration (B). The means and standard error of means of the individual means for each subject indicate the major changes during development. (Modified from Forssberg H, Kinoshita H, Eliasson AC, Johansson RS, Westling G [1992]. Development of human precision grip. II. Anticipatory control of isometric forces targeted for object’s weight. Experimental Brain Research, 90:393–398).
there are appropriately scaled forces toward the expected weight relative to the volume. When only the size of the object is co-varied and the weight is kept constant, the employed grip force rate is higher for the larger than the smaller object. However, adults and older children perceive the small objects as heavier. This indicates a dichotomy between the perceptual and motor systems because of the size-to-weight illusion (Charpentier, 1891). People predict a big object to be heavier than a small one, yet this is not always true. This understanding of the discrepancy between size and weight and a proper scaling of the motor output starts to develop at 3 years. Children younger than 3 are not able to control the motor output according to size but do use a higher grip force rate for heavier
Normal and Impaired Development of Force Control in Precision Grip • 53 Safety Margin 300
sp si
250 200 Percent
objects. This suggests that the associative transformation between the object’s size and weight involves additional demands of cortical processes, requiring further cognitive development. In children 3 to 7 years of age the difference between large and small objects is greater than in adults. Older children seem capable of reducing the effect if it is not purposeful for manipulation, whereas younger children still strongly rely on visual information (Gordon et al., 1992).
150 100 50
FRICTION Tactile influence on the force coordination is available on touching an object, contrary to weight influence, which is not available until lift-off. Tactile information from fingertips triggers prestructured motor commands based on sensorimotor memories and adjusts the force coordination based on the friction of the contact surface. The employed grip forces are different when one holds a slippery bottle than when holding a tool covered with rubber, even if they have the same weight. When contact pads on the test object are altered by exchangeable contact surfaces of silk and sandpaper, the relationship between grip force and load force is changed before lift-off. In adults there is an initial adjustment to the new frictional condition during the first 0.1 second and secondary adjustments during the loading and static phases (Johansson & Westling, 1987). These adjustments are important in establishing an adequate safety margin, which prevents one from dropping the object. The ratio between grip and load force actually used, minus the slip ratio necessary to prevent the object slipping out of the hand, makes up the safety margin. One-year-old children have a larger safety margin than adults. Gradually, the safety margin decreases in conjunction with increased coordination and less variability during the first 5 years (Figure 3-7). Some children of 18 months can scale the grip force based on tactile information in the beginning of the lift. They have a higher grip force for slippery materials than for rough ones during consecutive lifts with the same friction. Several years are necessary before children can handle objects with different frictional surfaces in the same elegant way as adults. Children younger than 6 years of age, sometimes up to 10 or 12 years, need several lifts and a predictable order to adjust the grip force to the current friction and form an internal representation before setting the parameters of the programmed motor output. The difference between adaptation to weight and adaptation to friction is that frictional conditions appear directly upon touching the object, whereas weight information is likely more crucial for anticipatory control because the weight is not available until lift-off. Grip forces of high amplitude
0
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t
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Figure 3-7 The mean and standard deviation of individual means of the safety margin for lifts with sandpaper and silk plotted for different age groups. The safety margin is expressed in percent of the slip ratio. Significant differences are indicated by an asterisk (p < 0.05). (Modified from Eliasson AC, Gordon AM, Forssberg H [1995]. Tactile control of isometric finger forces during grasping in children with cerebral palsy. Developmental Medicine and Child Neurology, 37:72–84.)
are a useful compensatory strategy to avoid dropping objects (Forssberg et al., 1995).
ORGANIZATION OF SENSORIMOTOR CONTROL These studies have enhanced our knowledge of the mechanisms underlying sensorimotor integration and anticipatory control in a grasping task. The model implies that for this manipulatory act visual, tactile, and proprioceptive information are integrated with memories of similar objects from previous manipulative experience. The appropriate muscles are then activated in the proper sequence based on the internal memory representation of the object, resulting in a well timed and coordinated grasping and lifting act. The act includes selection of motor programs that control orientation of the hand and the subsequent limb trajectories. These programs may be stored in sensorimotor (procedural or implicit) memory and used in an unconscious way, different from declarative (explicit) memory that is used in conscious recall of facts, events, and percepts (Squire, 1986) (see Chapter 6). The existence of sensorimotor memory has been demonstrated by disorders in higher brain function. It seems that networks involving cortical function, especially posterior parietal cortex, are important for anticipation. Jeannerod
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(1986) has described deficit in shaping the fingers toward the size of the object in patients with damage to the parietal area. The maturation of control mechanisms for the grasping movement continues throughout childhood. All measured parameters rapidly develop during the first years. Force coordination is poorly developed in 1year-old children; for example, they usually crush an ice cream cone, whereas children of 2 years manage quite well. There is a continuum of improvement of the parallel generation of grip and load forces as well as scaling of the forces toward the object’s different weight and friction. In 4-year-old children the motor output becomes less varied and more coordinated, in conjunction with a decreased safety margin. Children have more coordinated and adjusted movements and are able, for example, to carry a kitten and handle fragile objects. At that age there is even force scaling to the size of the object. However, the appropriate anticipatory scaling with acceleration of the lift to harmonize with the weight of the object is not developed until 6 to 8 years of age. Even so, there are still large variations in the ability to properly scale the forces according to frictional demands. It is not until ages 10 to 12 that scaling approaches adult levels. Efficient control of finger movements continues to develop until adolescence, when children can learn to play musical instruments and develop good handwriting with accurate speed. Obviously, there is parallel processing of cognitive functions and sensorimotor control during normal development. The maturation processes probably occur at many levels. Both the motor cortex and corticospinal tract with monosynaptic connections are important for precision grip and are highly related to force generation. In monkeys the monosynaptic projections to the spinal cord are not fully developed until the end of the first year (Lawrence & Hopkins, 1976). Myelination of the axons and increased conduction rate of cortical motor neuronal activity develop over several years and probably influence the temporal parameters of the lift (Muller, Hornberg, & Lenard, 1991). Because many areas of the brain are apparently involved in the grasping act, its full development obviously depends on establishment of appropriate synaptic connections between the cortex and all other areas associated with the act. These maturation processes are shown by reorganization of reflex responses with more efficient and faster triggering, which continues until adolescence (Evans, Harrison, & Stephens, 1990; Forssberg et al., 1991; Issler & Stephens, 1983). There are cortical networks mediating monosynaptic corticospinal projections to the motor neurons controlling distal muscles (Fetz & Cheney, 1980; Muir & Lemon, 1983), which
are active in fine manipulation and force regulation (Smith, 1981; Wannier, Toltl, & Hepp-Reymond, 1986). There may exist subcortical motor centers and even networks in the spinal cord important for storing certain motor acts; for example, the C3-C4 propriospinal system in cats can be used to mediate and update cortical commands for visually guided reaching (Alstermark et al., 1987). This provides several solutions for a particular movement through a wide range of central and peripheral inputs. During development there may be reorganization of networks in the spinal cord caused by increased descending control on premotor neurons. The descending control may break up the innate grasp reflex synergy allowing independent finger movement and may form a grip/lift synergy (Forssberg et al., 1991). Learning motor activities proceeds by trial and error; it is not really understood how the information from subsequent lifts is stored in memory to result in efficient programming. It is known that the anterior lobe of the cerebellum is involved in force regulation before a lift because the amplitude of the force is correlated with activity in neurons in this region, which has cutaneous and muscle afferent inputs from the hand (Espinoza & Smith, 1990). There are radical changes in synaptic activity, reflected in regional cerebral blood flow, during learning of motor sequence for finger movements. In the initial part of learning there is activation of the cortical areas, cerebellum, and structures providing information to those areas, namely the anterior language area and somatosensory association areas. As learning progresses, the activation in the language areas of the cortex disappears, leaving a reduced region in the somatosensory area, whereas different motor structures and the cerebellum show consistent increase in activity. This may mean that motor programs for motor sequence learning of finger movements are established and can be produced in a feed-forward strategy with less sensory information. It appears that memories are not stored in a single cell or in one particular cortical structure (Seitz et al., 1990).
IMPAIRED FORCE CONTROL AND CLINICAL IMPLICATIONS Clumsiness or impaired hand function may have different origins. The most common diagnoses of developmental disorders in children are ADHD, DCD, and CP. Although of different origin, they are all associated with more or less impaired force control during grasping (Eliasson et al., 1991; Forssberg et al., 1999; Pereira, Eliasson, & Forssberg, 2000). The dysfunction
Normal and Impaired Development of Force Control in Precision Grip • 55 could be seen as a continuum, with clumsy children at one end and severely impaired children with CP at the other. Children with CP have disturbed hand function because the primary or secondary lesions involve the sensorimotor cortex and the corticospinal tract, both of which have great implication for the performance of precision grips and for independent finger movement (Lawrence & Kuypers, 1968; Muir & Lemon, 1983) (see also Pehoski, Chapter 1). These children are known to be slow and weak with disturbed mobility of their finger movements (Brown et al., 1987; Ingram, 1966). In addition, they have different degrees of spasticity and tactile discrimination, especially those children with hemiplegic CP (Brown et al., 1987; Uvebrant, 1988). Little is known about the neural mechanisms that cause the impaired motor behavior in children with ADHD. The main problems are hyperactivity and poor attention, as indicated by the name, but about half of the children who have been diagnosed with ADHD also have motor problems (Barkley, 1990; Kadesjö & Gillberg, 1998). In particular, their fine motor skills are diminished (Szatmari, Offord, & Boyle, 1989; Whitmont & Clark, 1996), affecting, for example, their handwriting and performance on other highly skilled tasks (Doyle, Wallen, & Whitmont, 1995; Raggio, 1999). DCD is characterized by minor motor problems that occur as an isolated phenomenon in some children (American Psychiatric Association, 1994), which is to say that the minor motor problems appear without the symptoms attributable to ADHD but also can be found in conjunction with ADHD. These DCD children in the past were called “clumsy children” or children with motor coordination problems. The cause of the dysfunction is unknown but the group generally can be distinguished from typically developed children from the results of a test like the Movement ABC (Henderson & Sugden, 1992). As indicated, dysfunctioning prehensile force control is common to all children with ADHD, DCD, and CP.
FORCE COORDINATION When making a lift, the temporal pattern is rarely impaired in children with ADHD regardless of whether or not the ADHD is accompanied by DCD (Pereira et al., 2000); for children with CP, it is almost always disturbed to some degree. In these children the difference in the time at which the first finger or thumb makes contact with the object and the time at which the second finger makes contact is larger than in typically developing children, indicating disturbed coordination of finger movement and shaping of the fingers toward the size of the object, although there is a great deal of variation within the group, from almost as good
as the average of the control group to severely impaired (Eliasson et al., 1991; Forssberg et al., 1999). The parallel grip and load force typical of normal development rarely is seen. Instead, the forces increase sequentially with the grip force increasing before the load force (see Figure 3-5). Consequently, they do not produce the force rates in mainly bell-shaped profiles, but in stepwise, irregular, and extremely variable profiles (see Figure 3-4). However, this slow, sequential initiation of movements is an adequate strategy providing security in a manipulative task in which the coordination of force generation is not fully functional. For both groups of children (ADHD and CP), the grip force is larger and more unstable when performing a lift than it is for controls, in addition to which there is more variability between one lift and another (see Figure 3-4) (Eliasson et al., 1991). This large variability seems to be a characteristic of immaturity, as well as of dysfunction and impairment. It means that the children cannot repeat a task in the same way, or transfer the experience of performing one task to the performance of a similar one, making their performance unpredictable or clumsy. The relation between the development of force control and the severity of hand function has been demonstrated previously (Forssberg et al., 1999). However, the slow performance commonly observed in children with CP may be a good adaptation to their impairment. An example of the usefulness of such slow and sequential movement is evident when one considers the impaired release of the grasp. When efficiently putting down and releasing an object, including toys, the object has to be lowered and placed on a surface, not too quickly and not too slowly. This necessitates a low velocity of the movement close to the surface on which the object is to be placed (Figure 3-8). Then the force of the grasp ceases and the individual fingers are removed quickly and almost simultaneously. In a hemiplegic hand, a reversed pattern is found: The placement is performed fairly quickly, and the velocity of the movement is high upon making contact with the table, making the movement abrupt. Then it is hard for the child to decrease the force, resulting in a prolonged movement phase during which the fingers are released one at a time in an uncoordinated manner (see Figure 3-8) (Eliasson & Gordon, 2000). How can this knowledge be used in clinical practice? The case of a 4-year-old girl with hemiplegia playing with small plastic animals is one example. Every time she tried to lift and then place the horse, it fell. It was obvious that she was releasing the object too abruptly. By giving a simple instruction, “Straighten your fingers slowly,” she had the clue she needed to immediately
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Figure 3-8 Grip force from the index finger (ind) and thumb (th), grip force rate, load force, load force rate, vertical position, velocity, and acceleration as a function of time for representative trials during object replacement and release for one child in the control group and one child with hemiplegia. The grip and load force rates are shown using a ±20 point numerical differentiation. Vertical lines indicate the initiation of vertical displacement (T0), object contact with the table (T1), release of one digit (T2) and then the opposing digit (T3). The measured force parameters are shown by arrows indicating peak velocity (F1), peak load force rate corresponding to table contact (F2), minimum grip force rate (F3), grip force at replacement (F4), grip force at table contact (F5), and grip force at load force zero (F6) (dashed line in the right traces). (Modified from Eliasson AC, Gordon AM [2000]. Impaired force coordination during object release in children with hemiplegic cerebral palsy. Developmental Medicine in Child Neurology, 42:228–234.)
succeed. By analyzing her performance in the light of the knowledge that the hand of the child with hemiplegic CP has impaired force coordination, the therapist was able to give the girl precise information. The therapist recognized that although she appeared to be slow when replacing the horse, she was not slow enough in the crucial part of the action—when she had to loosen her grasp. That part had to be performed even more slowly, and she was able to succeed by increasing her awareness of that part of the movement sequence. Normally this behavior is performed in an unconscious way (i.e., by implicit processes) (Gentile, 1998). However, after a lesion has occurred in the CNS, it may be necessary to use an explicit process, at least in the early stage of learning. Knowledge about normal and abnormal behavior and the ability to analyze the task made it possible to give precise instructions. The idea was to help the child to learn how her impaired nervous system works and give her a strategy that could enable her to perform this task successfully; then she might be able to use the same strategy when releasing other objects in different situations (Eliasson, 2005).
ANTICIPATION OF THE PROPERTIES OF OBJECTS During normal development small children are able to scale the force that needs to be applied when gripping an object even before the action starts, taking into account the weight and friction, as well as the size of the object. This happens even before the typical parallel force coordination with the mainly bell-shaped force rate profile is developed. Hardly any of the children with CP who were aged 6 to 8 years, or the children with ADHD plus DCD who were 9 to 15 years, scaled the force amplitude appropriately for different weights, whereas children with only ADHD anticipated the weight fairly well (Eliasson et al., 1992; Pereira et al., 2000). This indicates that a different type of dysfunction (diagnosis), at least on a group level, influences the ability to scale the motor output. Although children with ADHD plus DCD can apply an appropriate force the first time they lifted a familiar object such as a glass, or an unopened packet of milk, they cannot do this efficiently with an unfamiliar object, when they have only seen but not touched or lifted it (Pereira
Normal and Impaired Development of Force Control in Precision Grip • 57 et al., 2000). Appropriate force involves anticipatory scaling. That means that when heavier and larger objects such as an unopened packet of milk are to be lifted, the child increases the load force at a greater rate during the initial lifts than when lifting smaller light objects like the glass. Children with ADHD plus DCD are able to build up a memory representation of the object, although this is not as efficient as for typically developed children and adults. This deficient control was also demonstrated in a group of children with hemiplegic CP who were unable to scale the force output to match the weight of a previously lifted object until they had lifted the object at least 15 times. This has to be compared with the one or two times necessary in age-matched peers (Gordon & Duff, 1999). However, most participants with CP demonstrated anticipatory scaling when lifting familiar objects, which means that they are capable of learning by practice, despite having a dysfunctional nervous system. The question, then, is how this practice should be planned and performed. An investigation was carried out in another experiment in which children lifted novel objects that varied in weight in either a blocked series, with one weight being lifted several times, or a random series in which different weights were randomly assigned to be lifted (Duff & Gordon, 2003). Blocked practice resulted in greater differentiation of the force rates between objects during acquisition than random practice. However, both types of practice resulted in similar performance retention 24 hours later. These findings suggest that children with hemiplegic CP are able to build up internal representations that are used for anticipatory force scaling of novel objects, and that practice is valuable, although it appears that the type of practice schedule employed is not important. The importance of practice can be demonstrated by adolescents with hemiplegic CP who were practicing Frisbee golf using their hemiplegic hand. Being able to throw a Frisbee as well as possible toward a target requires the ability to plan the direction of the movement, use a certain amount of force, and release the grasp with exact timing. Playing Frisbee with a hemiplegic hand may seem crazy, but it was an activity practiced at a 2-week, 5-day-a-week day camp in which the adolescents were treated by Constraint Induced Movement Therapy (Eliasson et al., 2003). The goal of the Frisbee game was to traverse a 350-foot-long course, at the end of which was a basket. The object of the game was to use the fewest number of throws to get the Frisbee in the basket. Nine adolescents practiced 30 minutes for 7 days during the day camp. All adolescents improved at this game, and the number of throws needed to get the Frisbee into its basket
decreased from the first to the last day of camp, from 20 (range 14 to 35) to 14 (range 12–18) (Eliasson et al., 2003). It appears that it is possible to improve at Frisbee golf, as well as to learn to scale the force output during grasping applied to objects by practice, at least for these groups of children with CP.
SENSORY I NFORMATION USED FOR FORCE CONTROL Sensory information is essential for prehensile force control because it provides the nervous system with information about different aspects of the physical properties of objects in the immediate environment and, as described, it is used for anticipatory scaling and to adjust ongoing movements. Sensory impairments have been described for children with hemiplegic CP but have not been observed in children with diplegic CP or ADHD (Uvebrant, 1988). In children with hemiplegic CP, a decrease in two-point discrimination and stereognosia occurs in 50% to 70% of children. Processing of proprioceptive information also is impaired. This can be seen during vibration of a muscle, in which the muscle spindles are stimulated, giving rise to an illusion of arm movement; this illusion occurs in normal children, but only in 50% of children with CP (Tardieu et al., 1984). However, there is an unclear relationship between the perceived sensation of this kind and the ability to adjust the force output to match the physical properties of an object. All children with CP who participated in earlier studies perceived the difference between weight and frictional contact surfaces of the object to be lifted although some of them had decreased two-point discrimination and stereognosis. That is, almost all of them have decreased ability to transform sensory information into appropriate “settings” for a motor command. There was no simple correlation between two-point discrimination and ability to adjust the force output based on frictional condition of the object (Eliasson et al., 1995). This may indicate that two point discrimination needs to be processed at a higher level in the central nervous system than adjustment of forces for grasping. The children with CP should be able to rely on sensory feedback for grasping because, as mentioned, their anticipatory control is impaired. Relying on sensory feedback means that the forces increase in a steplike manner, permitting sensory feedback, until liftoff. This results in a prolonged loading phase for heavier objects, but fairly well-adjusted forces taking into account both the weight of the object and the friction of the contact surfaces during the static phase when the object is held still in the air (Eliasson et al., 1992, 1995). Yet there is large variation in the grip
Part I • Foundation of Hand Skills
force applied during the isometric force coordination, making the performance unpredictable and, of course, inconvenient for daily life. This is a common feature in the early development of all children, including children with different diagnoses (Eliasson et al., 1991; Brogren, Forssberg, & Hadders-Algra, 2001; Pereira et al., 2000). A way of solving this problem is to increase the safety margin to prevent objects from being dropped. This compensatory behavior was obvious in all the children with CP who were investigated. It is evidently a successful compensatory strategy for those with impaired sensory processing, lack of anticipatory control, and slow adaptation (Eliasson et al., 1995). However, it does make it difficult to handle fragile objects because there is a danger that the object will be crushed, and it also makes it difficult for children with CP to handle heavy objects because, in this case, a high level of force is needed and weakness is a common problem in children with CP. The question that needs to be addressed is: How can children with sensory dysfunction learn to handle objects as efficiently as possible? Sensory information is crucial for the performance of precise movements. Tactile information is the most important information for discrete finger movements, whereas proprioception is more important for reaching in different directions and handling objects of different weights. Tasks in which tactile information is crucial are, for example, buttoning up a shirt, picking raspberries, and opening a door with a key. For many bimanual tasks, having intact sensibility in only one hand does not terribly influence the task performance because people usually hold the object (an action requiring less sensory information) with their impaired hand and manipulate (requires efficient tactile regulation) with their dominant hand (Krumlinde-Sundholm & Eliasson, 2002). However, an important compensation for tactile disturbance is to use visual information. Vision strongly influences manipulatory actions and should not be overlooked when attempts are made to gain a deeper understanding of how the somatosensory systems influence manipulatory actions. The ability to use visual information as a form of compensation was seen when the results of hand surgery were evaluated. Children with CP and impaired sensibility tended to benefit more or at least as much from upper limb surgery as measured by a timed dexterity task than children with intact sensibility (Figure 3-9) (Eliasson, Ekholm, & Carlstedt, 1998). This probably has something to do with the ability to “see the grasp” being performed after surgery because before the surgery was performed, the hand was pronated, the wrist was flexed, and the thumb was in-palm, making it impossible to see the grasping act as it was conducted. After surgery, in contrast, the hand was more extended and supinated
Dexterity before and after surgery 140 120 100 Sec
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Figure 3-9 Dexterity, in seconds when moving 10 cubes and placing them on the opposite side of a vertical border on the table. Individual results of 11 subjects with normal two-point discrimination (2PD) and 14 with impaired 2PD before and after surgery. 2PD: 3 to 4 mm was tested for in a randomized order, their fingers were touched with a distinct but light touch with one or two points, 10 times on each finger. Before examination, the task was demonstrated for them to see and feel the differences between one and two points on both hands. Normal 2PD required at least eight correct answers on two of three digits. The time decreased 14.5 s (md) compared with 9 s (md) for children with normal sensation. (Modified from Eliasson A.C, Ekholm C, Carlstedt T [1998]. Hand function in children with cerebral palsy after upper-limb tendon transfer and muscle. Developmental Medicine in Child Neurology, 40:612–621.)
and the thumb was able to meet the fingers, making it possible to use vision to compensate for impaired sensibility. This may indicate that impaired sensation could be an indication for surgery, at least from one perspective. This is opposite to what commonly is recommended but has to be considered. One other important way to compensate for lack of control that should not be overlooked is to concentrate and pay deliberate attention to the performance of the task. The compensatory strategies are crucial, but they often make the children slower.
SUMMARY Motor control—meaning how the CNS controls movement—is complex, but by understanding the principles of how movements are organized, it is possible to use the knowledge that has been gained to plan intervention. By using this perspective we can help children to learn more about themselves and help them find more efficient ways to use their possibilities rather than focusing on the impaired or odd movement. An important perspective to put across is that there is nothing
Normal and Impaired Development of Force Control in Precision Grip • 59 wrong or right about a movement, rather, when there is a task that needs to be performed, it can often be done in a number of different ways. As therapists, we can help them to learn themselves by adopting strategies and ensuring that repetition consolidates improvements. Thus, if knowledge of motor control is used alongside the principles of motor learning, a new and useful concept of treatment results. In addition, it should be remembered that we do not know the relationship between the maturation of the CNS and the performance of different tasks; however, we do know that practice is necessary. Given this, it seems logical that a less efficient nervous system needs more practice than an appropriately functioning one. It is also known that improvement in any task strongly depends on motivation. Improvement induced by motivation is shown nicely in a task measuring pronation and supination of the hand: The children are induced to increase their range of movement by hitting a drum rather than by just performing the movement (van der Weel, van der Meer, & Lee, 1991). For the children concerned, it is the game itself that is the goal: They are not interested in the specific movement of arms and hands, and the therapist should remember this. For success in skills, the therapist should encourage children to find tasks they are motivated to repeat and learn, working on their possibilities rather than on their limitations. We have to bear it in mind that the task performance we see may look odd from a perspective of “normal” movements, but it may be a solution to a problem based on their way to handle their impaired nervous system
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D Ottoson (editors): Somatosensory mechanisms. London, Macmillan. Johansson RS, Westling G (1987). Signals in tactile afferents from the fingers eliciting adaptive motor responses during precision grip. Experimental Brain Research, 66:141–154. Johansson RS, Westling G (1988). Coordinated isometric muscle commands adequately and erroneously programmed for the weight during lifting task with precision grip. Experimental Brain Research, 71:59–71. Johansson RS, Westling G (1990). Tactile afferent signals in the control of precision grip. In M Jeannerod (editor). Attention and performance. Hillsdale, NJ, LEA. Kadesjö B, Gillberg C (1998). Attention deficits and clumsiness in Swedish 7-year-old children. Developmental Medicine and Child Neurology, 40:796–804. Konishi M (1965). The role of auditory feedback in the control of vocalization in the white-crowned sparrow. Zeitschrift Tierpsychologie, 22:770–783. Krumlinde-Sundholm L, Eliasson AC (2002). Comparing tests of tactile sensibility: Aspects relevant to their use in testing children with spastic hemiplegia. Developmental Medicine and Child Neurology, 44:604–612. Lawrence DG, Hopkins DA (1976). The development of motor control in the rhesus monkey: Evidence concerning the role of corticomotoneuronal connections. Brain, 99:235–254. Lawrence DG, Kuypers HGJM (1968). The functional organization of the motor system in the monkey. I. The effects of bilateral pyramidal lesions. Brain, 91:1–14. Lund JP, Olsson KA (1983). The importance of reflexes and their control during jaw movement. Trends in Neuroscience, 6:458–463. Miller AJ (1972). Significance of sensory inflow to swallowing. Brain Research, 43:147–159. Mott FW, Sherrington CS (1895). Experiments upon the influence of sensory nerves upon movement and nutrition of the limbs. Proceedings of the Royal Society of London. Series B: Biological Sciences, 57:481–488. Muir RB, Lemon RN (1983). Corticospinal neurons with a special role in precision grip. Brain Research, 261:312–316. Muller K, Homberg V, Lenard HG (1991). Magnetic stimulation of motor cortex and nerve roots in children. Maturation of corticomotoneural projections. Electromyography and Clinical Neurophysiology, 81:63–70. Nottebohm F (1970). Ontogeny of bird song. Science, 167:950–956. Okado N (1980). Development of human cervical spinal cord with reference to synapse formation in the motor nucleus. Journal of Comparative Neurology, 191:495–513. Okado N (1981). Onset of synapse formation in the human spinal cord. Journal of Comparative Neurology, 201:211–220. Pereira HS, Eliasson AC, Forssberg H (2000). Detrimental neural control of precision lifts in children with ADHD. Developmental Medicine and Child Neurology, 42:545–553. Raggio DJ (1999). Visuomotor perception in children with attention deficit hyperactivity disorder-combined type. Perception and Motor Skills, 88:448–450. Roland PE, Ericsson L, Widen L (1989). European Journal of Neuroscience, 1:3–18. Ruff HA (1984). Infants’ manipulative exploration of objects: Effects of age and object characteristics. Developmental Psychology, 20:9–20.
Normal and Impaired Development of Force Control in Precision Grip • 61 Seitz RI, Roland PE, Bohm C, Greitz T, Stone-Elander S (1990). Motor learning in man: A positron emission tomographic study. Neuroreport, 1:57–66. Smith AM (1981). The co-activation of antagonist muscles. Canadian Journal of Physiology and Pharmacology, 59:733–747. Squire LR (1986). Mechanisms of memory. Science, 232:1612–1619. Szatmari P, Offord DR, Boyle MH (1989). Ontario child health study: Prevalence of attention deficit disorder with hyperactivity. Journal of Child Psychology and Psychiatry, 30:219–230. Tardieu G, Tardieu C, Lespargot A, Roby A, Bret MD (1984). Can vibration-induced illusions be used as a muscle perception test for normal and cerebral-palsied children? Developmental Medicine and Child Neurology, 26:449–456. Uvebrant P (1988). Hemiplegic cerebral palsy: Aetiology and outcome. Acta Pediatrica Scandinavica Supplement, 345. Vallbo B (1970). Discharge patterns in human muscle
spindle afferents during isometric voluntary contractions. Acta Physiologica Scandinavica, 80:552–566. van der Weel FR, van der Meer ALH, Lee DN (1991). Effect of task on movement control in cerebral palsy: Implications for assessment and therapy. Developmental Medicine and Child Neurology, 33:419–426. von Hofsten C, Ronnquist L (1988). Preparation for grasping an object: Developmental study. Journal of Experimental Psychology: Human Perception and Performance, 14:610–621. Wannier TMJ, Toltl M, Hepp-Reymond M-C (1986). Neuronal activity in the postcentral cortex related to force regulation during a precision grip. Brain, 382:427–432. Wilson DM (1964). The origin of the flight-motor command in grasshoppers. In RF Qeiss (editor): Neuronal theory and modeling. Palo Alto, Stanford University Press. Whitmont S, Clark C (1996). Kinaesthetic acuity and fine motor skills in children with attention-deficit-hyperactivity disorder: A preliminary report. Developmental Medicine and Child Neurology, 38:1091–1098.
Chapter
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PERCEPTUAL FUNCTIONS OF THE HAND Sharon A. Cermak
CHAPTER OUTLINE DEVELOPMENT OF HAPTIC PERCEPTION Haptic Perception in Infants Haptic Perception in Children Gender and Hand Differences in Haptic Recognition and Haptic Accuracy Summary and Implications for Practice FUNCTIONS CONTRIBUTING TO HAPTIC PERCEPTION Role of Somatosensory Sensation in Haptic Perception Role of Manual Manipulation and Exploratory Strategies in Haptic Perception Role of Vision and Cognition in Haptic Perception Summary and Implications for Practice EVALUATION OF HAPTIC PERCEPTION IN INFANTS AND CHILDREN HAPTIC PERCEPTION IN CHILDREN WITH DISORDERS Prematurity
used for carrying out everyday activities such as tying shoes or buttoning. As a perceptual organ it seeks and processes information such as when searching for a coin in a pocket. The two functions of the hand are closely intertwined. Rochat (1989) emphasized that “from the origin of development, action is under some perceptual or sensorimotor control and the picking up of perceptual information is somehow inherent in any performed act” (p. 871).
However, when the hand performs a practical action, its perceptual functioning is regulated by what is needed to achieve this action, whereas when the hand acts primarily as a perceptual system, its motor activity is primarily exploratory and information seeking. This chapter concerns the hand as a perceptual or information-seeking organ. Focus is on active touch (haptic perception) rather than passive touch. Passive touch involves only the excitation of receptors in the skin and underlying tissue; “active touch involves the concomitant excitation of receptors in the joints and tendons along with new and changing patterns in the skin” (Gibson, 1962, p. 482).
Brazelton has suggested that, whereas
Mental Retardation Brain Injury Learning Disabilities and Related Disorders Summary and Implications for Practice SUMMARY The hand has two closely related functions: It is both an executive and a perceptual organ (Bushnell & Boudreau, 1998; Gibson, 1988; Hatwell, Streri, & Gentaz, 2003; Lederman & Klatzky, 1998). As an executive organ it is
“passive touch may add to an infant’s ability to initiate and maintain control, active touch … acts as an alerter and as information. It helps the infant come to a receptive alert state and begin to process information” (Rose, 1990, p. 316).
Haptic perception deals with the retrieval, analysis, and interpretation of the tactile properties (e.g., size, shape, texture) and identity of objects through manual and in-hand manipulation (Bushnell & Boudreau, 1993; Hatwell, 2003). The process of tactile scanning is complex and includes the blending of feedback from tactile,
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kinesthetic, and proprioceptive sensations. The tactile spatial properties of objects are obtained through the retrieval of information about the relationship of the objects to the body and gravity during active manual exploration. The study of haptic perception has been closely associated with the study of visual perception. Researchers have attempted to gain insight into how we use our visual and haptic senses to function by comparing the ability to match objects through the use of vision and haptic manipulation. These studies typically require the subject to match a standard (test) object to a set of two or more comparison objects. If the subject is asked to do an intramodal comparison, both the standard and comparison objects are analyzed using the same sensory modality (visual or haptic sense). If the subject is asked to do an intermodal comparison, the standard object is analyzed using one sense and the comparison object(s) are analyzed using the other sense. In this chapter research methodology is specified as containing intramodal or intermodal matching, whereas the senses used appear in parentheses (standard comparison). For example, intermodal (haptic-visual) matching means that the haptic sense was used to analyze the standard or test object and the visual sense was used to select from among the comparison objects. The term multimodal exploration refers to the simultaneous use of the visual and haptic senses in object investigation. In this chapter the review of intramodal matching (matching using the same sensory system) is limited to haptic-haptic matching in which the subject feels the standard or test object and then feels several comparison objects to find the match. One goal of this chapter is to provide the reader with an understanding of selected aspects of haptic perception that may influence effective evaluation and treatment of children with suspected and identified impairments in haptic perception. Topics covered include the development of haptic perception, functions contributing to haptic perception, evaluation of haptic perception in infants and children, and haptic perception in children with neurologic disorders. The adult literature has been included to the degree to which it assists our understanding of the current status of the pediatric research.
DEVELOPMENT OF HAPTIC PERCEPTION HAPTIC PERCEPTION IN I NFANTS In the infant the hands and mouth are both potential sources of haptic information. The mouth can be used to gain information about the shape and substance of
objects (Ruff, 1989). Pecheux, Lepecq, and Salzarulo (1988) found evidence suggesting intramodal (haptichaptic) recognition of shapes inserted into nipples by 2 months of age. As the infant develops, the hands become a perceptual system that increasingly participates in the infant’s construction of knowledge (Bushnell & Boudreau, 1998; Hatwell, 1987). Manipulation of an object facilitates the learning of the object’s characteristics. During exploratory play of the first year, infants begin to learn about their environment, their bodies, and how their actions can effect change (Gibson, 1988). Current research has indicated that haptic abilities are much more efficient in infants than was thought in the past (Streri, 2003a). Use of the habituation paradigm adapted from vision research has shown that early intramodal (haptic-haptic) manual exploration in infants provides consistent haptic discrimination (Hatwell, 1987; Streri & Pecheux, 1986). In this paradigm infants are given shapes to manually explore with a screen preventing the infants from seeing their hands. The amount of interest the infant devotes to the object is measured by the amount of time the object is grasped, and as the infant habituates, he or she holds the object for shorter periods of time. Using two pairs of shapes, Streri and Pecheux (1986) observed a haptic habituation to a familiarized shape and a reaction to novelty (longer holding) when a new shape was presented to 4- and 5-month-old infants. This was noted in infants as young as 2 to 3 months (Streri, 1987). Streri and Pecheux (1986) reported that infants required a longer period of time to habituate to tactile stimuli than to visual stimuli and suggested that this may be explained, in part, because information can be obtained more quickly visually than tactually. In a similar haptic habituation paradigm, 6- and 7-monthold infants with severe visual impairments also were found to show haptic integration for shape and texture (Catherwood et al., 1998). Research with infants also has shown that young infants evidence intermodal integration. Rose, Gottfried, and Bridger (1978) concluded that 6-month-old infants could integrate visual and haptic perception as evidenced by their ability to visually recognize a shape after only tactile contact with it. Streri and colleagues completed a series of studies that supports even earlier development of visual-haptic integration and haptic object perception (Streri, 2003b; Streri & Gentaz, 2004; Streri et al., 2004; Streri & Molina, 1993; Streri & Spelke, 1988, 1989). For example, responses of 4- to 5-month-old infants to visual images of objects were assessed after bilateral object handling without opportunity for visual regard of the hands (Streri & Spelke, 1988, 1989). One object presented was two rings connected by a solid bar; the other object was two rings connected by a string. The infants produced
Perceptual Functions of the Hand • 65 different types of arm movements when holding the different objects. The infants were shown visual displays of two rings either connected or separated, which were moving as they typically did while the infants were holding them. The infants looked longest at the rings that were dissimilar to those that they had held. This was the expected response if the infants perceived the similarities between the rings that they held and moved and those that they saw moving. Streri and Spelke (1988) concluded, “infants evidently perceived connected or separated objects by detecting the patterns of common or independent motion that they themselves produced.” (p. 19).
They also noted that the infants held the objects for relatively long periods, as much as five times as long as they would have been expected to visually attend to an object. Because these 4-month-old infants were so competent at identifying objects tactually and visually, Streri and colleagues (Streri, 2003a; Streri & Spelke, 1988) questioned Piaget’s theory that vision and touch become integrated through haptic exploration of objects and suggested that this ability may be present without substantial experience in handling objects. In a recent study of cross-modal recognition in newborns, Streri and Gentaz (2004) have even suggested that under some limited conditions, newborns have the ability to extract shape in a tactile format and transfer it to a visual format, independent of common experience. Molina and Jouen (1998, 2001, 2003) also reported that newborns can discriminate between rough and soft textures and modify their grasping according to the texture of the grasped object.
HAPTIC PERCEPTION IN C HILDREN Much of the literature on haptic perception in children deals with the recognition of common objects (e.g., comb, penny) and shapes (e.g., circle, square, diamond). However, the hand also is used to gain information about other object properties, such as texture, hardness, size, weight, and spatial orientation. Each is discussed.
Recognition of Common Objects and Shapes One of the most well-known studies on the development of haptic perception in children is that of Piaget and Inhelder (1948/1967). They presented a series of solid (three-dimensional) common objects and cardboard cutouts of shapes (geometric figures and topologic forms) to a group of 2- to 7-year-old children and asked the children to feel each figure and then visually select the figure from among a set of figure drawings. The geometric figures used ranged from simple (e.g., circle, ellipse, square) to complex (e.g., star, cross, semicircle). Topologic forms were shapes with irregular
surfaces containing one or two holes or having openings or closings on their outer edges. These authors found that the ability of children to identify objects and shapes by touch progressively improved with increased age. Children 21⁄2 to 31⁄2 years of age were able to correctly recognize common objects but were unable to identify shapes. By 31⁄2 to 5 years of age children developed the ability to match topologic forms. Recognition of geometric figures emerged at 4 to 41⁄2 years with the ability to differentiate curvilinear (circle and ellipse) from rectilinear (square and rectangle) shapes. The ability to recognize geometric figures in greater numbers and levels of complexity was shown to progressively improve from 41⁄2 to 7 years of age. Benton and Schultz (1949) also studied intermodal (haptic-visual) matching of common objects in a group of 156 3- to 5-year-old children and found that performance progressively improved with age. Three-yearold children typically were able to recognize 50% of the items presented (mean 4.0 out of eight items). Fouryear-old children performed only slightly better than children in the 3-year-old age group (mean = 4.5). Near-perfect performance typically was found by 5 years of age, with most children correctly recognizing at least seven of the eight objects presented. Hoop (1971a) also studied intermodal (hapticvisual) matching at 31⁄2 to 51⁄2 years. Like Piaget and Inhelder, Hoop found the identification of common objects to be easier than the recognition of topologic forms and geometric figures. There was little variation in the ability of 31⁄2- to 51⁄2-year-old children to match topologic forms (means ranging from 2.3 to 2.6 out of a maximum score of 4). Miller (1971) reported a similar finding. The 3- and 4-year-old children in her study were able to identify fewer than half of the intermodally (haptic-visual matching) and intramodally (haptic-haptic matching) presented shapes. Like Piaget and Inhelder, Hoop found the recognition of topologic forms through intermodal (haptic-visual) matching to be easier than the identification of geometric figures. However, this has not been a consistent finding (Derevensky, 1979). Derevensky (1979) suggested that listing shapes as topologic or geometric may be an incorrect method of categorization, and suggested that it may not be whether a shape is topologic or geometric but the nature of the distinctive features that it contains that contributes to task difficulty. Another interesting finding was reported by Abravanel (1972), who noted that, in a series of intermodal (haptic-visual matching conditions, it was easier for 6- to 8-year-old children to identify solid (threedimensional) than flat (two-dimensional) geometric figures. She attributed this to possible variation in the usefulness of the manipulation strategies used by the children in shape exploration. This topic is discussed in depth in a later section of this chapter.
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Recently, Bushnell and Baxt (1999) examined haptic recognition of familiar versus unfamiliar objects. They found that 5-year-old children more accurately identified familiar than unfamiliar objects; however, this varied as a function of whether the matching was haptic-haptic or haptic-visual. For unfamiliar objects, haptic-haptic matching was more accurate than hapticvisual matching, whereas there was no difference for familiar objects. Familiar objects were identified more accurately than unfamiliar objects in a haptic-visual matching task, but there was no difference as a function of familiarity in the haptic-haptic matching task. A limitation of the study is that a ceiling effect was reached for familiar objects, with many participants achieving maximum scores. There is general agreement that the haptic perception of common objects is well developed by 5 years of age, and the ability of children to select geometric figures through intermodal (haptic-visual) matching emerges at about 4 years of age (Abravanel, 1972; Blank & Bridger, 1964; Hoop, 1971a; Micallef & May, 1979; Piaget & Inhelder, 1948/1967). Like the finding of Piaget and Inhelder, all of these studies have noted improvement in accuracy with increasing age. Moreover, with increasing age, children change their representation of objects from one based primarily on global shape to one that incorporates a balance of global shape and specific local parts (analytical mode) (Berger & Hatwell, 1993, 1995; Morrongiello et al., 1994). However, whereas some researchers reported that young children primarily used global strategies to categorize objects, others found that both children and adults primarily used analytic modes (Schwarzer, Kufer, & Willkening, 1999). Within this mode, Schwarzer found a developmental sequence in the attribute chosen for categorization of objects. They found that focusing on surface texture decreased with age and focusing on shape increased with age. Thus children preferred substance-related attributes, especially surface texture, whereas adults preferred the structure-related attributes, especially shape. This was consistent with Berger and Hatwell (1993), who also found a preference for surface texture as an analytic attribute.
Recognition of Texture, Size, and Weight Unlike shape or orientation, length, or localization in the environment, in which vision is superior to touch, texture perception is often as good haptically as visually (Gentaz & Hatwell, 2003). Haptic discrimination of texture, size, and weight has been shown to improve with increasing age in 4- to 9-year-old children (Gliner, 1967; Miller, 1986; Siegel & Vance, 1970). Gliner further found rough textures to be easier to identify than smooth textures, with third grade subjects showing a lower threshold (greater sensitivity) to texture stimuli than kindergarten subjects.
Intermodal (haptic-visual) discrimination of diameter and length has been reported to emerge at 4 years and continues to mature into adolescence, with variation in diameter being easier to recognize than variation in length (Abravanel, 1968a,b; Connolly & Jones, 1970; Hulme et al., 1983). When analyzing length, children found tasks requiring intramodal (vision or haptic) discrimination easier than those requiring intermodal (vision and haptic) discrimination for object comparison (Hulme et al., 1982, 1984). Research comparing children’s preference for the use of texture, size, and shape in object recognition suggests that there may be a developmental progression in preferential use of these sensory properties. Preference for the use of texture over shape in object identification during intramodal (haptic-haptic) matching tasks has been found to occur in young children (4 to 5 years of age) but not in older children (Berger & Hatwell, 1993, 1995; Gliner, 1967; Schwarzer et al., 1999; Siegel & Barber, 1973; Siegel & Vance, 1970), although Schwarzer and co-workers (1999) found that the exploratory strategy varied as a function of the task requirements and the feedback. Size has been shown to be more difficult to discriminate than texture in children 4 and 8 years old (Miller, 1986). Gliner and co-workers (1969) further found that the preference of kindergartners for texture over shape in object identification in an intramodal (haptic-haptic) matching task decreased as the textured surfaces became more difficult to identify. Preference for the use of shape over texture and size during intramodal (haptic-haptic) matching of objects was cited by Siegel and Vance (1970) and Gentaz and Hatwell (2003) in kindergarten through third-grade children. Adults preferred size or shape classification (Gentaz & Hatwell, 2003). Miller (1986) further found that variation in shape interfered with accuracy in identification of texture during intramodal (haptic-haptic) matching in 8-yearold children but not in 4-year-old children. She concluded that this might be because 4-year-old children ignored shape cues when texture was available for use in object discrimination. Thus it is possible that during tasks requiring haptic discrimination, children might use the sensory property that produced the strongest distinctive features. As the ability to recognize shapes improves with age, there might be increased preference for the use of shape over other properties for object identification because shape yields distinctive features that are more useful in object recognition than texture or size. If this hypothesis is correct, then the properties selected for use in object recognition might be age and task dependent. They might vary based on both the degree to which the distinctive features provided by the object were easy to identify and the developmental level of haptic perception (e.g., texture, shape, size) exhibited by the child being tested.
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Recognition of the Spatial Orientation of Objects Few studies have addressed the development of haptic spatial orientation in children. Perceptual awareness of the constancy of spatial location through the use of vision and haptic exploration has been shown to develop at an early age. Three-year-old children who were blind were able to identify common objects after 180 degrees of object rotation (Landau, 1991). Hatwell and Sayettat (1991) asked 4- to 7-year-old children to reseat a doll at a table inside a doll house after the child, the doll, the table, or the house was rotated. Many of the 4-year-old children were able to successfully reseat the doll in the initial location after rotation using intramodal (visual or haptic) exploration. An age-related increase in accuracy of doll placement occurred between ages 4 and 6 years. The shape of the table had no effect on task performance. Children of 41⁄2 years in a study by Abravanel (1968a) could visually recognize test objects facing up, down, or rotated but had difficulty when intermodal (haptic-visual) matching was necessary for task completion. Intermodal recognition of up-down was no better than chance until 5 years of age, and the identification of rotated figures was not possible until 6 years of age. Pick, Klein, and Pick (1966) used intramodal (visual-visual and haptic-haptic) matching tasks to study children’s ability to differentiate the up-down orientation of letter-like forms. They reported that the task could be performed more easily through the use of vision than touch. No relationship was found between subjects’ ability to perform the task through the use of vision versus touch, leading the authors to conclude that perhaps the method used in coding and discriminating spatial orientation is different for the two sensory modalities. However, it is also possible that some types of objects might just be better suited for processing through one sensory system than the other. For example, letter-like forms may represent a type of object that is easily processed through the visual system but not easily analyzed through the tactile system. In a recent review of research examining processing of spatial object properties and the oblique effect (whether orientation is perceived more accurately in the horizontal and vertical planes than the oblique plane), investigators concluded that gravitational cues play a role in the haptic perception of orientations in blindfolded (sighted) adults and children (Gentaz & Hatwell, 2003; Gentaz & Streri, 2004). This is similar to the oblique effect found for orientation with vision.
G ENDER AND HAND DIFFERENCES IN HAPTIC RECOGNITION AND HAPTIC ACCURACY Several studies have examined whether boys and girls perform differently in the accuracy of haptic perception and whether one hand is more accurate than the other.
Research generally has shown that boys and girls 3 to 14 years old display equal ability to recognize common objects, shapes, and words through intramodal (haptichaptic) and intermodal (haptic-visual) matching (Abravanel, 1970; Affleck & Joyce, 1979; Ayres, 1989; Benton et al., 1983; Benton & Schultz, 1949; Bushnell & Baxt, 1999; Cioffi & Kandel, 1979; Cronin, 1977; Etaugh & Levy, 1981; Gliner, 1967; Klein & Rosenfield, 1980; Kleinman, 1979; Witelson, 1976; Wolff, 1972). Occasionally boys have been identified as exhibiting greater skill than girls in the intramodal (haptic-haptic) matching of objects by texture, size, and shape (Gliner, 1967). In addition, Siegel and Barber (1973) found boys to display a stronger preference than girls for the use of form over texture in the intramodal (haptic-haptic) matching of shapes. Most studies conducted on normal adults have shown there to be no difference in the overall accuracy of haptic perception between men and women (Cronin, 1977; Kleinman, 1979; McGlone, 1980). When handedness is examined, children often display greater left- than right-hand skill in some forms of haptic perception (Hahn, 1987; Rose et al., 1998); however, the strength and age of onset of this difference vary among studies (Streri, 2003c). The finding of greater left- than right-hand skill on some tasks, particularly those requiring discrimination of meaningless shapes, has been viewed as related to right hemisphere superiority in the processing of spatial information (e.g., Witelson, 1974, 1976). In a recent meta-analysis of cerebral specialization of spatial abilities, Vogel, Bowers, and Vogel (2003) found a right-hemisphere preference when subjects were performing spatial orientation and manual manipulation tasks. However, because the age of onset of right–left hand differences varied widely across studies, it is inappropriate to interpret the presence or absence of a hand difference for stereognosis as being related to the maturity of hemispheric specialization for haptic perception in a given child. Consistent evidence of a right–left hand difference for stereognosis did not appear until adolescence.
SUMMARY AND I MPLICATIONS FOR PRACTICE The ability to distinguish the texture, shape, and substance of objects through the use of intramodal (haptic-haptic) and intermodal (haptic-visual and visual-haptic) exploration develops over a long period. It begins to emerge in early infancy and continues to mature into adolescence. Infants are amazingly adept at using haptic exploration with the mouth and hands to learn about objects in their environment. Early haptic discrimination using the mouth is seen at 1 month of age or even earlier, and haptic discrimination using the hands appears at 1 to
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2 months of age. Intermodal transfer of information between the haptic and visual senses begins at 4 to 6 months, although recent evidence suggests that even newborns have limited ability. This means that by the second half of the first year of life infants can explore an object using the hand and then recognize the same object as being similar or different using vision. Haptic perception improves with increasing age. Children find common objects easier to haptically recognize than topologic forms, geometric figures, or unfamiliar objects. At 21⁄2 years, children can identify many common objects through use of the haptic sense. Haptic recognition of common objects reaches full maturity by about 5 years. Intramodal (haptic) and intermodal (haptic and visual) identification of topologic forms and geometric shapes emerges at 3 to 4 years and continues to develop throughout childhood. With increasing age children are able to match forms or shapes having increasingly complex distinctive features. They also are able to move from recognizing only solid (three-dimensional) shapes to being able to also distinguish flat (two-dimensional) figures. Hapticvisual matching generally is better than visual-haptic matching. Thus in developing a program to enhance children’s haptic matching abilities it is best to start with familiar objects, with haptic-visual matching preceding visual-haptic matching. Like adults, children show greater left than right hand skill in some forms of haptic perception, possibly reflecting specialization of the right hemisphere for the processing of spatial information. However, the age at which hand preference for haptic processing emerges varies across studies. Although some authors suggest that haptic perception may be better in boys than girls, most studies have not found a difference. The literature contains less information about the development of sensory properties such as texture and weight in childhood. It is known that children find rough textures easier to match than smooth textures. The development of texture discrimination improves between 4 and 9 years, in part because tactile sensitivity increases during this time span (Gliner, 1967). The discrimination of diameter and length begins at about 4 years and continues into adolescence, with variation in diameter being easier to recognize than variation in length. Children as young as 3 to 4 years can recognize the spatial orientation of an object when the child or object has been rotated, but it is not until 5 to 6 years that children can haptically identify objects as facing up, down, or rotated. Children’s ability to haptically analyze objects having two or more tactile properties is limited. Rather than analyzing several sensory properties simultaneously as adults do, children appear to select one sensory property to use in object analysis. The sensory
property selected seems to be the one that is easiest for the child to recognize, perhaps because it exhibits the strongest distinctive features. For example, texture is preferred to shape and size in young children, whereas older children are more likely to match objects by shape than texture. In addition, the coexistence of several sensory properties in a given object can impair haptic discrimination at some ages. This finding suggests that haptic figure-ground may be an issue in haptic object discrimination, a factor that needs to be considered in the development of tests and training programs in haptic perception. We do not know whether the ability to distinguish objects by shape, size, texture, or weight develops sequentially or simultaneously. Research suggests that children develop the ability to discriminate all of these sensory properties, including texture, hardness, weight, and temperature. Thus it is logical to conclude that we should provide children with ample opportunity to analyze objects having varying sensory properties. When presenting activities designed to promote the development of haptic perception, we should vary objects by one sensory property and also offer objects with a combination of sensory properties. If the child has the opportunity to sort objects haptically in a variety of ways, he or she is likely to identify or sort objects using the sensory property that has the strongest distinctive features or use exploratory procedures or strategies that are most well developed in his or her repertoire. The sensory properties that the child consistently avoids using may be those that are most delayed and thus most in need of being addressed in treatment. Because little is known about the development of haptic figure-ground perception in children, we do not know if the finding of impaired haptic discrimination in multisensory haptic play activities is normal or a sign of impairment. However, we can be sensitive to the signs of haptic sensory overload in children. It is possible that playing with toys having several sensory properties may be disorganizing for some infants and children. When problems are seen, controlling the variety, as well as the quantity of sensory experiences may be necessary to elicit optimum performance during school and play activities.
FUNCTIONS CONTRIBUTING TO HAPTIC PERCEPTION Most haptic perception tasks are complex. Research suggests that various factors contribute to haptic perception, including somatosensory processing, manual and in-hand manipulation, and vision and cognition.
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ROLE OF SOMATOSENSORY SENSATION IN HAPTIC PERCEPTION Vierck (1978) proposed that sensory feedback processed through the dorsal columns may guide exploratory hand use. Although the firing of haptic neurons in the sensorimotor cortex often is credited for guiding exploratory hand use and contributing to the ability to recognize objects by touch, synaptic connections among many central nervous system (CNS) structures are involved in the process (Carpenter, 1991; Goodwin & Wheat, 2004; Mountcastle, 1976). Recent research examining neural substrates of tactile object recognition using functional magnetic resonance imaging (in adults) found that tactile object recognition involved a complex network including parietal and insular somatosensory association cortices, as well as occipitotemporal visual areas, prefrontal, and medial temporal supramodal areas, and medial and lateral secondary motor cortices (Reed, Shoham, & Halgren, 2004). Disruption in communication anywhere within this circuit logically could result in loss or impairment of the ability to explore objects with the hands. A synthesis of information derived from somatosensory receptors provides the hand with a dynamic picture of the body and its orientation in space (body scheme) (Gardner, 1988; Goodwin & Wheat, 2004). This internal picture of the body is thought to be used by CNS processes as a framework of the parameters of real-world time and space (Brooks, 1986). Upon this framework are scaled motor commands used in motor programming and executing complex sequenced movements. This internal picture of the body also is thought to serve as a template for interpreting the spatial properties of objects (Gibson, 1962). The precise detail of this internal picture of the body decreases and its spatial complexity increases with progressive afferent processing in the CNS (Brooks, 1986). Not only does somatosensory sensation contribute to the development of body scheme needed for the interpretation of the spatial properties of objects, but it also appears to be necessary for regulating manual and in-hand manipulation during active touch. Research with children with spastic hemiplegia found that deficient tactile sensitivity was strongly related to the manual dexterity needed for exploration (Gordon & Duff, 1999; Krumlinde-Sundholm & Eliasson, 2002). The sensory control of hand movements is discussed in Chapter 1. At present it seems sufficient to note that to actively retrieve somatosensory sensation from the environment during active touch the individual must be able to make rapid and frequent changes in the speed and sequencing of hand movements and regulate force during object manipulation (Hollins & Goble, 1988; Johnson & Hsiao, 1992). These elements of fine
motor coordination are thought to be related, in part, to the processing of tactile, kinesthetic, and proprioceptive sensations for their execution (Brooks, 1986; Case-Smith, 1995; Case-Smith, Bigsby, & Clutter, 1998; Duque et al., 2003; Gordon & Duff, 1999; Johansson & Westling, 1988, 1990).
ROLE OF MANUAL MANIPULATION AND EXPLORATORY STRATEGIES IN HAPTIC PERCEPTION Manual exploration and in-hand manipulation are critical for haptic perception and object recognition (Lederman & Klatzky, 1998, p. 27). It has been suggested that information from the motor commands generating exploratory actions generates corollary discharge or efferent copy and is involved in haptic perception, although the mechanisms are not well understood (Jeannerod, 1997). Interest in the role of in-hand manipulation and other forms of manual exploration in haptic perception was precipitated by the work of Gibson (1962) on active and passive touch. Using a set of geometricshaped cookie cutters, adult subjects either were allowed to actively manipulate the cookie cutters or the tactile stimuli were passively presented by the examiner (cookie cutters pressed or pressed and turned in the palm of the subject’s hand). The use of active touch contributed to greater accuracy in intermodal (hapticvisual) shape recognition than either of the passive touch conditions, although pressing and turning the cookie cutters in the subject’s hand (passive pressure with movement) yielded higher scores than the isolated use of passive pressure. Replication of Gibson’s study with children yielded similar findings (Haron & Henderson, 1985). Cronin (1977) also replicated Gibson’s study but obtained somewhat different results. She found that shape recognition by school-age children and young adults did not differ between active touch and passive touch (passive pressure with movement) conditions when tactile stimulation was restricted to the palm of the hand in all test conditions; however, the isolated use of passive pressure (passive pressure without movement) contributed to lower test scores than either of the other two test conditions. In addition, no difference between active touch and passive touch (pressure with movement) was found for the discrimination of texture and tactile maze learning in adults (Lederman, 1981; Richardson, Wuillemin, & MacKintosh, 1981). These findings suggest that it might be movement of the object over the skin surface that produces the tactile feedback needed for object recognition. Although movement of the object in the hand theoretically can be active or passive, it is most
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commonly produced actively, through the use of manual manipulation and exploratory strategies. This raises the question of how the pattern of tactile feedback generated by variation in the pattern of manual and in-hand manipulation affects the accuracy of object identification. In recent years several researchers have attempted to answer this question; their findings are discussed in the following section. See Chapter 8 for a detailed discussion of in-hand manipulation. Because most of the research on this topic has been done on adults, this section begins with a summary of the adult research followed by a review of the pediatric literature.
Haptic Manipulation Strategies in Adults In a series of studies, researchers (Klatzky, Lederman, & Reed, 1987; Lederman & Klatzky, 1987, 1990, 1998) found that adults were highly systematic in the manual exploration strategies they used. Adults performed “a variety of stereotypical hand movement patterns” (Lederman & Klatzky, 1998, p. 27), including lateral motion, pressure, static contact, unsupported holding, enclosure, and contour following, that Lederman and Klatzky called “exploratory procedures or EPs” (p. 27). These strategies were selected based on the particular object property the adult desired (e.g., hardness, texture, shape). Early research on the influence of manipulation strategies in object recognition was done by Davidson in a series of studies comparing the ability of sighted and congenitally blind subjects to recognize raised curved edges. Davidson (1972) and Davidson and Whitson (1974) found that when exploring concave, convex, and straight edges, subjects chose to use three manipulation strategies (gripping, pinching the edge, and sweeping the fingers over the top edge). Gripping (grasping the object in the hand) led to fewer errors in identifying the form of the curved edges in both blind and sighted subjects. Gripping was later found to be a useful strategy for obtaining a general understanding of the objects’ tactile properties (e.g., texture, weight, shape) (Klatzky et al., 1987; Lederman & Klatzky, 1987). The method of gripping (called enclosure in some studies) was modified to aid in differential discrimination of size and shape. Subjects preferred to grip with the whole hand when analyzing the size of objects and grip, with effort, the edges of the object using the fingers and palm when analyzing shape (Reed & Klatzky, 1990). Although gripping provided subjects with a general classification of object properties, other strategies often were used when refined analysis was needed. Contour following (moving the fingers around the edge of the object) was an optimum strategy for use in haptic shape recognition (Lederman & Klatzky, 1987). In a thorough analysis of strategies used in the
identification of geometric shapes, Kleinman and Brodzinsky (1978) found that subjects preferred to use a combination of manipulation strategies, including an initial scanning of the standard and comparison objects. This was followed by detailed simultaneous comparison of the standard and comparison objects (congruent feature comparison of analogous and mirror-image features and contour following). The initial time spent in scanning the objects was reduced as the shapes became more complex. Locher and Simmons (1978) found that haptic recognition of symmetric shapes was more difficult than the recognition of asymmetric shapes. Partial trace scanning (contour following along portions of the shape) was common for asymmetric shapes. More complex scanning strategies were used for the identification of symmetric shapes (several repetitions of partial and complete contour following). In a subsequent study Simmons and Locher (1979) found use of the trace scanning strategy (contour following around the complete shape several times using two fingers) to lead to greater accuracy in the identification of asymmetric shapes and the simultaneous apprehension scanning strategy (smooth, continuous movement of thumb and index fingers of both hands over opposite sides of the shape simultaneously) to lead to greater accuracy in the identification of symmetric shapes. The results of these studies suggest that the isolated use of contour following may not always be the most appropriate approach for use in the identification of shapes. It may be necessary to change manipulation strategies to adapt to variation in symmetry of distinctive features and complexity of the objects presented. Lederman and Klatzky (1987) analyzed manipulation strategies used for the identification of texture, hardness, weight, volume, and temperature. They found that the optimum manipulation strategy (which they termed exploratory procedures) for use in object identification differed for each tactile property (Table 4-1). Although contour following was necessary for accurate recognition of shape, several approaches could be used for the identification of most other tactile properties (Box 4-1). Preferred manipulation strategies remained unchanged when subjects were asked to determine the gradations of a given tactile property (texture, size, shape, and hardness) and when they needed to simultaneously sort pouches (fabric-covered shapes) by one to three of these tactile properties (Klatzky, Lederman, & Reed, 1989; Lederman & Klatzky, 1987). Enclosure (gripping) was commonly used for all tactile properties, with lateral motion being used primarily for the identification of texture, pressure being primarily used for the identification of hardness, and contour following being used primarily for the identification
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Table 4-1
Haptic procedures associated with acquiring knowledge about objects
Object Dimension
Exploratory Procedure
SUBSTANCE Texture Hardness Temperature Weight
Lateral motion Pressure Static contact Unsupported holding
STRUCTURE Weight Volume Global shape Exact shape
Unsupported holding Enclosure; contour following Enclosure Contour following
FUNCTION Part motion Specific function
Part motion test Function test
Data from Lederman SJ, Klatzky RL (1987). Hand movements: A window into haptic object recognition. Cognitive Psychology, 19:342–368.
BOX 4-1
Most Effective Strategies Used for Identification of Tactile Properties (Other Than Recognition of Shape)
1. Texture: lateral motion (moving the finger across the surface of the object) 2. Hardness: pressure 3. Weight: unsupported holding* 4. Volume: enclosure (gripping) 5. Temperature: static contact *Jiggling while holding the object aided in the discrimination of weight. Brodie EE, Ross HE (1985). Jiggling a lifted weight does aid discrimination. American Journal of Psychology, 98:469–471.
of shape and size. When pouches needed to be simultaneously sorted by two or three properties, the manipulation strategies were combined, with lateral motion and pressure often being merged into a single finger movement. When the properties of texture and shape needed to be analyzed, adults appeared to search for cues about texture before they searched for cues about the object’s shape (Lederman, Brown, & Klatzky, 1988). Subjects showed a preference for manipulation strategies that could simultaneously
analyze two tactile properties. Exploration time decreased when subjects used lateral motion and pressure to simultaneously discriminate texture and hardness and when they used gripping (enclosure) to simultaneously discriminate size and shape (Klatzky, Lederman, & Reed, 1989; Reed & Klatzky, 1990). This finding suggests that adults may prefer manipulation strategies that simultaneously explore multiple sensory properties. Not only do subjects select haptic manipulation strategies based on the tactile properties of objects, they also organize manipulation strategies into a sequence. Lederman and Klatzky (1990) found haptic exploration in adults consisted of a two-stage sequence. The first stage consisted of generalized exploration of the object using manipulation strategies such as gripping (enclosure) or unsupported holding (object resting in the palm of the open hand), strategies that provided awareness of the general tactile properties of the object. This was followed by a second stage of refined manipulation, in which the subject used more specialized manipulation strategies (e.g., contour following, lateral motion) to gain specific information about object characteristics. During the second stage the subject often alternated between different manipulation strategies to guide the retrieval of information about the object. In summary, results of research on haptic manipulation and exploratory strategies provide support for the hypothesis that the pattern of tactile feedback generated by variation in patterns of manual manipulation during active touch contributes to the accuracy of object recognition. Adults select manipulation strategies based on the tactile properties of the object being explored. Furthermore, they combine and sequence the use of these manipulation strategies in situations in which conditions require the simultaneous or sequential analysis of several tactile properties. The sophisticated haptic manipulation strategies seen in adults develop throughout childhood.
Haptic Manipulation Strategies in Infants Haptic exploration begins in early infancy. Neonates and young infants gain much information about objects from action with their mouth. At 2 and 3 months spontaneous interaction with a novel object starts with an oral contact (Rochat, 1989). Ruff and co-workers (1992) reported that oral exploration or mouthing increased until 7 months, and then decreased through 11 months in favor of manual manipulation. By 4 months, even though vision emerged as the initial modality of exploration, infants continued to frequently bring the object to their mouth. Spontaneous behavior by infants suggests increasing multimodal (visual and haptic) organization of exploration, with vision playing a growing role. According to Rochat (1989), the hands
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serve both transport and support functions, bringing the object alternately into the oral zone and the field of view for exploration. Ruff (1989) described a dual role of handling: the hands make information available to the eyes as the object is manipulated at the same time that the hands directly gather haptic information. In the first role the hands are used to manipulate the object and change the object’s location relative to the observer, such as turning the object around to provide different visual perspectives. In the second role the hands gather haptic information about the object, such as by pressing the object to determine its substance or rubbing a finger across the object to determine its texture or shape. Based on their developmental work, Bushnell and Boudreau (1991, 1993, 1998) suggested that the motoric capacities needed to perform exploratory procedures limit haptic perception in the young infant. In conjunction with the early development of multimodal exploration, the characteristics of object manipulation change from 2 to 5 months. At 2 to 3 months the infant’s manipulative behaviors are primarily limited to grasping movements, potentially informing the infant about the object’s substance, temperature, and size (Bushnell & Boudreau, 1991, 1993). Although slight finger movements are produced at 2 months, by 4 months the occurrence of fingering behavior increases significantly (Rochat, 1989). Because discrimination of texture requires isolated finger movements, texture discrimination does not begin until around 6 months of age. Before this, when both hands are involved in contacting an object, it is primarily for transporting the object to the mouth. Rochat (1989) noted that in young infants (2 to 4 months) bimanual coordination is initially linked to the oral system. This observation points to the importance of the mouth in the early manifestation of bimanual action in the context of object manipulation. The hand–mouth coordination seen in the 2- to 4-month-old infant is later combined with vision when behaviors such as fingering emerge. To more thoroughly assess how infants use object handling skills to gain information for recognition of specific object qualities, Ruff (1984) studied 6-, 9-, and 12-month-old infants and assessed the various manipulation strategies they used, including mouthing, fingering, transferring, banging, and object rotation. Fingering proliferated with increased age, particularly with objects that varied in texture. Ruff suggested that this fingering can be crucial for obtaining information about small object details. Hand use for object rotation also was noted to change, with all infants using a onehanded rotation pattern, in which the arm or wrist moves, but only older infants using two-handed object rotations. Ruff suggested that two-handed rotation can be particularly useful because with rotation the object does not have some parts covered by the hand. She
suggested that infants who cannot adjust their handling skills so they can finger objects rather than just hold them and infants who cannot effectively use two hands together may be limited in the complexity of information about objects that they can readily gather. Discrimination of shape does not occur until between 9 and 12 months when the infant learns to turn and rotate an object in two hands (Ruff, 1989). Given that adults use a flexible repertoire of exploratory strategies and that certain actions may be particularly useful for obtaining specific information about objects, the question also has been asked how, during development, young infants and children tailor their actions to explore objects (Palmer, 1989). Whereas earlier work has suggested that infants’ actions were not clearly related to object attributes (McCall, 1974), current research has found that exploratory action patterns are indeed influenced by object characteristics and that the actions of the infant are related in functional ways to the structure of the environment (Gibson, 1988; Hatwell et al., 2003). In a series of studies, Ruff (1980, 1984, 1989) examined the effect of object characteristics on infant manipulation strategies. In a study of 9- and 12month-olds, Ruff (1980) found that infants fingered objects with surface texture more than they fingered smooth blocks. Ruff (1984) investigated 6- to 12month-old infants’ manipulation of a range of objects varying in color, shape, texture, and weight and found that manual exploration was adapted to the visual and the tactual properties of the object. When infants were given objects that varied in shape, they rotated the objects and transferred them from one hand to the other hand; when objects had varying surface textures, infants fingered the objects, often scratching their surface. Weight change resulted in less looking and more banging than did other changes in object characteristics. In a more recent study Ruff (1989) found that by 7 to 9 months infants banged hard objects more than soft objects, banged more on hard surfaces than on soft surfaces, and fingered textured objects more than smooth objects. In a study of 12-month-old infants’ haptic exploration and discrimination, Gibson and Walker (1984) found that infants squeezed, rubbed, and pressed a spongy object more than a rigid object and banged the rigid object more than the spongy one. The results of these studies suggest that infants adjusted their manipulative behavior to the characteristics of objects. Palmer (1989) also found that infants 6, 9, and 12 months old tailored their actions to particular object and table characteristics. Palmer recorded the manipulative behavior of infants with 12 different objects of varying rigidity, texture, shape, weight, and sound potential using two different table surfaces (hard wood
Perceptual Functions of the Hand • 73 BOX 4-2
Actions Used by Infants in Object Exploration
Grasping Banging Fingering Mouthing Switching (hand to hand) Squeezing Rubbing Pressing Poking Slapping Scooting Dropping
and foam covered). Results indicated that infants made use of both object properties and table surface properties. For example, infants banged more on the wood surface. Age differences in actions were also noted. Palmer suggested that these differences may reflect developing action economy (e.g., waving the bell with a flick of the wrist rather than with the whole arm swing seen in younger infants), new exploratory systems (e.g., changing from mouthing to waving and banging), and increasing fine motor control (e.g., finger individuation). Case-Smith and co-workers (1998) examined 120 2- to 12-month-old infants and also found that infants’ grasp and manipulation strategies varied as a function of the objects’ haptic attributes (size, shape, contour, movable parts) and the child’s age. They found that objects with movable parts elicited more varied and mature manipulation strategies and suggested that objects with movable parts and multidimensional surfaces “facilitate haptic development and motor skill by affording the infant a variety of surfaces to explore and by sustaining the infant’s interest” (p. 108). Research suggests that even infants younger than 6 months detect an object’s perceptual features that enable particular actions (affordances) for hand and mouth. Rochat (1983, 1987) found that neonates showed differential oral and manual responding to objects varying in substance and texture. In a study of 3-month-old infants, Rochat (1989) noted that the characteristics of manual manipulation and exploration by the infant reflected some relation to the physical properties and affordances of the object (Box 4-2).
Haptic Manipulation Strategies in Children Research with children has focused primarily on analysis of the role of manipulation strategies in the development of haptic discrimination of shape and size (length). Results of these studies suggest that there is a
Table 4-2
Developmental progression for haptic discrimination of shapes and objects
Age Range
Haptic Strategy
21⁄2 to 4 years
Children may play with object (e.g., push), but there is no active manual exploration; grasping or touching of object is seen with palm being still when making contact with object; by 3 to 6 years child begins to make discoveries about discriminative features seemingly by chance
4 to 5 years
Exploration often remains passive, with object being grasped between palm and middle fingers; crude manual exploration begins; when manual exploration is seen, it is done in a global haphazard manner, which includes probing for distinctive features
5 to 6 years
Systematic use of both hands (palms and fingers) begins; isolated analysis of distinctive features without studying whole form can be observed
6 to 7 years
Use of systematic method of exploration can be seen; contour following is used
developmental progression in the acquisition of manipulation strategies, with the accuracy of object identification being related to the level of sophistication of the haptic manipulation strategies (Abravanel, 1968b; Hatwell, 2003; Hoop, 1971b; Jennings, 1974; Kleinman, 1979; Wolff, 1972; Zaporozhets, 1965, 1969). The description of the developmental progression of haptic discrimination of common objects and shapes in Table 4-2 is a summary of the work conducted by Piaget and Inhelder (1948/1967) and Zaporozhets (1965, 1969). Whereas haptic strategies of the 2- to 4-year-old child consist primarily of grasping the object, by age 6 to 7 years systematic exploration with contour following is noted. Abravanel (1968b) provided a description of the developmental progression in haptic manipulation of size (length) that was strikingly similar to that identified
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Examples of Manipulation Strategies
If children want: • To compare two objects for texture, they use a lateral motion, often with the index finger. • To compare hardness, they use pressure. • To examine temperature, they use static contact. • To examine volume of three-dimensional objects, they tend to embrace the object. • To compare weight, they tend to hold the object in their hand and lift it from the surface. Hatwell Y (2003). Manual exploratory procedures in children. In Y Hatwell, A Streri, E Gentaz (editors): Touching for knowing (pp. 67–82). Philadelphia, John Benjamins Publishing; Klatzky RL, Lederman SJ (2003). The haptic identification of everyday life objects. In Y Hatwell, A Streri, E Gentaz (editors): Touching for knowing (pp. 105–122). Philadelphia, John Benjamins Publishing; Klatzky RL, Lederman SJ, Metzger VA (1985). Identifying objects by touch: An “expert system.” Perception and Psychophysics, 37:299–302; Streri AF (2003a). Manual exploration and haptic perception in infants. In Y Hatwell, AF Streri, E Gentaz (editors): Touching for knowing (pp. 51–66). Philadelphia, John Benjamins.
for the analysis of common objects and shapes. She found that the youngest children in her study (3 to 5 years) typically used the palm of the hand, grasping and palpating the objects. By 5 years the children held the ends of the bar used for evaluating length. From 5 through 8 years children used the whole hand (palm with progressively increasing use of the fingers) for manipulation of the bar and displayed a systematic method of determining length. By 9 years, use of the palm was no longer seen; the fingers and fingertips were used for exploration. Researchers have shown that the manipulation strategy used by the child or adult varies as a function of the information to extract (Box 4-3) (Hatwell, 2003; Klatzky & Lederman, 2003; Klatzky, Lederman, & Metzger, 1985; Streri, 2003a). In summary, the results of studies that address analysis of strategies used in the recognition of common objects, shapes, and sizes, including lengths, suggest that manipulation strategies become more complex with increasing age, a maturational change that seems to contribute to the accuracy of haptic object recognition. The structural characteristics of the test materials influence the time spent in haptic exploration, perhaps because they contribute to task difficulty or they affect the complexity of manipulation strategies needed for object exploration. The effect of object characteristics on the use of manipulation strategies has been extensively addressed in infants, and
to a lesser extent in preschool and school-age children. Infants use a variety of actions in exploring objects (see Box 4-2). These actions vary as a function of the object and surface characteristics; that is, they are influenced by the perceptual affordances provided by the environment, as well as by the infants’ motor abilities.
ROLE OF VISION AND COGNITION IN HAPTIC PERCEPTION Vision McLinden and McCall (2002) emphasize that most skills and activities are performed with information from multiple modalities simultaneously. They discuss the role of vision in coordinating or integrating a wide range of sensory information. Warren and Rossano (1991) describe the important role that vision plays in the development of haptic perception. Noting that vision and touch are constant companions, Pears and Jackson (2004) discuss how the brain dynamically binds together visual and somatosensory information to construct accurate representations of objects in space, and emphasize the importance of this linkage for acting on objects in the world around us. Rochat (1989) noted a major link between vision and fine haptic exploration early in development and suggested that vision may serve as a potential organizer of multimodal exploration and object manipulation in infancy. This was based on research that indicated that fingering starts to manifest itself in coordination with vision. Refined object manipulation was more likely to occur when infants simultaneously looked at and manipulated objects. Thus it may be important for infants to see their hands during manual object manipulation. As further support of the role of vision as an organizing factor of object manipulation, Rochat (1989) cited developmental studies of congenitally blind infants, who exhibited drastic delays in the use of their hands as exploratory tools (Fraiberg, 1977). Even though congenitally blind toddlers spontaneously developed strategies such as object rotation (Landau, 1991), haptic exploration was primarily oral up to 3 to 4 years of age, much longer than was seen in sighted infants. Thus the use of vision in object exploration may be important for the development of haptic perception. However, this is not to say that haptic perception cannot be developed in the absence of vision. For example, Schellingerhout, Smitsman, and Van Galen (1997, 1998) examined the haptic exploratory procedures of surface textures in eight infants, 8 to 24 months old, who were congenitally blind. They found that younger infants showed a wide range of exploratory strategies and older infants used these strategies in a specific manner.
Perceptual Functions of the Hand • 75 Hatwell (1990) suggested that even sighted children between the ages of 3 months and 6 years have difficulty using their hands for retrieving haptic information independent of vision. She suggested that the motor functions of young children’s hands were primary, with the perceptual capabilities of the hands rarely used except as an adjunct to motor functioning. Hatwell noted that when vision was used, the hands primarily operated under this system of control. Ruff (1989) tempered this view by stating that it may be that the visual system guides exploratory behavior in the haptic system. In this sense, vision would not exclude the contribution from the haptic system as put forward by Hatwell (1987) but would constrain it. Ruff (1989) suggested that there was an “initial tightening of visual control over manipulation around 5 months of age [and] then the loosening of visual control sometime after nine months” (p. 313). Haptic manipulation with vision is important in the early learning of object characteristics and has two potential advantages. First, as infants look at an object they are manipulating, they see the object from different points of view and can learn about its properties. This is critical for the development of object recognition so that the infant or child can recognize an object in any orientation or in any context. Second, the infant acquires tactile and kinesthetic information about the object through active touch (Ruff, 1980, 1982; Streri, 1993, 2003a). Ruff (1980) suggested that movement is particularly important in helping infants to detect the properties of an object that does not vary despite changes in the object’s orientations. An important question is what type of movement is necessary. For example, the infant can produce different information about the object through his or her own movements such as through turning the head to look at the object, by moving the body around the object, or by holding, manipulating, and moving the object. Alternatively, the infant can get different views of an object when a parent carries the infant around the room, or when the object itself moves, as in a mobile, or when a parent moves the object, such as in the context of showing a toy to a child. Ruff (1980) hypothesized that object transformations that occur during movement allow for detection of object characteristics that would not be evident from observing a stationary object. She also suggested that, although both watching object movement and producing object movement were important in learning about objects, producing movement could yield the specific types of information sought and therefore was a more efficient way of learning about objects. The advantage to the individual doing the moving is that infants learn to recognize objects in the context of activity. Ruff (1980) found that 6-month-
old infants learned structural differences in objects only when they actually manipulated the objects; viewing object movement did not result in the learning of object characteristics. It should be emphasized that, in the manipulation condition, the infants also visually monitored their movements, thus obtaining tactile, proprioceptive, and visual information. Ruff proposed that the advantage of object manipulation may be in the simultaneous use of visual and tactile integration in learning about object qualities. The heavy use of vision in object identification seen in infants may continue into adulthood. Research comparing visual and haptic discrimination has shown visual matching to be consistently superior to haptic and intermodal (haptic-visual and visual-haptic) matching (Garbin, 1988; Hatwell et al., 2003). This finding has left the impression that vision may be more important than haptic discrimination in object identification. Nevertheless this may be an incorrect interpretation of the research findings. Klatzky and co-workers (1985) questioned this conclusion, stating that it might be inappropriate to use objects that can be easily interpreted by the visual system when evaluating functions of the tactile system. Rather than vision being superior to haptic manipulation, it would probably be more accurate to say that vision and somatosensory processing both play supportive roles in object identification. Although vision seems to be used by infants and young children to guide exploratory hand use, its purpose may not be to substitute for haptic perception but rather to guide the development of haptic manipulation and make the somatosensory input meaningful.
Cognition The development of infants’ and young children’s exploration of the environment is linked to their understanding and knowledge about the world (Bushnell & Boudreau, 1998; McLinden & McCall, 2002). Because cognition and vision are closely linked in haptic object identification, it is difficult to categorize certain functions, such as mental imagery, that involve both cognition and vision. The ability to use cognitive strategies (mental imagery and verbalization) to aid in haptic object recognition develops during childhood. Piaget and Inhelder (1948/1967) considered the ability to distinguish objects through the use of touch to be an external reflection of one’s capacity to transform tactile properties of objects into visual images (integrate visual and haptic information), although recently this view has been questioned. This ability to use visual imagery to improve haptic recognition and memory of objects is thought to contribute to children’s ability to recognize objects on tests of haptic perception and reproduce objects through drawing. In fact, research has shown that adults with high spatial ability and skill in
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mental imagery perform significantly better than their less skilled peers on tests of haptic perception (McCormick & Mouw, 1983). Verbalization (labeling of the haptic properties of objects) also has been found to aid in haptic object identification. Bailes and Lambert (1986) compared the ability of adults who were sighted and blind to determine if four segments of a stimulus figure matched a completed geometric design. The subjects who were sighted were faster and more accurate than the subjects who were blind. Adult subjects who used verbalization had better haptic accuracy scores than subjects who used a mixture of verbalization and mental imagery. Subjects who solely used mental imagery displayed the lowest haptic accuracy scores. Thus in some tasks, verbalization may be a more effective strategy than mental imagery, although both may be beneficial. The ability to use cognitive strategies (mental imagery and verbalization) to aid in haptic object recognition develops during childhood. Children 3 to 6 years of age often could not describe the strategies that they used to aid in haptic object identification (Blank & Bridger, 1964). By the fourth grade several solely used verbalization or mental imagery, whereas most relied on a mixture of verbalization and visual imagery to aid in haptic object identification (Ford, 1973). Adults were evenly mixed in their isolated use of verbalization and mental imagery, and combined use of the two cognitive strategies (Bailes & Lambert, 1986). Alexander, Johnson, and Schreiber (2002) examined the effect of 4- to 9-year-old children’s domain-specific knowledge on their performance in haptic comparison task. Children with varying levels of knowledge about dinosaurs haptically explored pairs of familiar (dinosaur) and unfamiliar (sea creature) models and were asked to state whether or not the pairs were identical. Older children correctly identified more pairs than younger children and explored models more exhaustively. Although dinosaur knowledge did not affect overall performance, it did affect the types of explorations that to some extent resulted in increased errors. Specifically, after exploring the first object, children with high knowledge about dinosaurs tended to form an initial hypothesis (e.g., based on one feature such as the beak) and then sought evidence to confirm this initial hypothesis by primarily exploring just the beak of the possible matches. In doing this, they ignored or failed to seek out evidence (e.g., exploring the dinosaur’s feet) that did not confirm their hypothesis.
SUMMARY AND I MPLICATIONS FOR PRACTICE Several functions contribute to the ability to perform haptic perception tasks. Because an individual performs poorly on tests of haptic perception does not mean that
somatosensory processing is impaired. Impairment in somatosensory processing, vision, visual perception, cognition, praxis, and any factor that may alter fine motor coordination has the potential to lower performance on tests of haptic perception. Determining the reason for a child’s poor test performance is a necessary prerequisite for effective treatment planning. In the clinic we may be able to gain some insight into the maturity of the somatosensory system by observing the tendency of infants to mouth and manipulate novel objects. Although infants use vision extensively in object exploration, we should expect to see a combination of visual and oral or manual exploration during play in infancy. Although research indicates that optimum performance in haptic identification is seen when manual manipulation is used for object identification, haptic perception can be partially assessed without active manipulation. Research has shown that placement of the object in the palm of the hand and movement of the object across the skin’s surface improves object recognition. Thus the therapist can occlude the child’s vision, move the object across the center of the palm, and then ask the child to identify the object by visual matching or verbal response. Analysis of the quality of the haptic manipulation strategies used during test performance also provides useful diagnostic information. The preferred manual manipulation and exploratory strategies of adults vary for objects with different tactile properties. The manipulation strategy used affects the accuracy of object identification. Research suggests that the development of haptic manual manipulation and exploratory strategies begins early in life, because infants use specific manipulation strategies to explore specific sensory properties. During childhood these manipulation strategies grow in complexity with increasing age. We do not know whether children with problems in haptic perception and fine motor coordination fail to use appropriate manipulation strategies because they have difficulty in the selection or execution of haptic manual manipulation and exploratory strategies. However, it is generally recognized that the immature haptic manipulation strategies seen in young children contribute to poor object recognition (Abravanel, 1968b; Derevensky, 1979; Hatwell, 2003; Hoop, 1971b; Jennings, 1974; Wolff, 1972; Zaporozhets, 1965, 1969). Early haptic exploration in infancy is done with the mouth. It is more than a year before mouthing is primarily replaced by manual manipulation. We cannot overemphasize the clinical importance of mouthing objects in infancy. Mouthing of objects not only seems to be important for decreasing oral hypersensitivity and facilitating oral motor development, but it also appears to be important for environmental learning and may
Perceptual Functions of the Hand • 77 contribute to the early development of bilateral hand use. Infants who exhibit little mouthing of objects should be evaluated to determine the cause of the delay. Even older children who exhibit tactile defensiveness and those with problems in haptic discrimination should be encouraged to engage in oral and manual exploration of objects. It takes creativity and close interaction with parents to find socially acceptable ways to encourage mouthing beyond infancy. Children also can show a prolonged need for mouthing of objects. If the behavior is caused by oral-tactile defensiveness or poor haptic discrimination, then mouthing should be encouraged. However, if the behavior is caused by impaired visual-haptic integration or poor purposeful use of objects, then treatment should be directed toward pairing vision and oral-manual manipulation during purposeful interaction with objects. A bigger challenge is seen in children with multiple handicaps and those who have severe impairment in motor function. We should help these infants incorporate mouthing of toys into daily play activities and find ways to attach toys to clothing and position equipment so that toys can easily reach the mouth. Vision is paired with haptic exploration of the hands throughout infancy and early childhood. Vision appears to guide the development of haptic manipulation strategies. It is not until later in life that vision and somatosensory sensations appear to take on separate but supportive roles in object identification and use. The importance of vision in the development of haptic manipulation is seen in blind infants. Whereas typical infants begin to replace mouthing with manual manipulation at about 4 months, blind infants continue to identify objects orally, with mouthing the dominant form of exploration until 3 or 4 years of age (Landau, 1991). Because vision appears to be necessary for the development of haptic manual manipulation, the use of haptic exploration with the hands should be specifically taught to blind infants; we cannot assume that, because the infant is not using vision, he or she will automatically use the hands for environmental exploration. Interplay between vision and haptic exploration seems to be needed for environmental learning in infancy and early childhood. Under the age of 5 or 6 years activities should be designed that pair vision and touch in addition to using the haptic sense alone. The identification of object features should be integrated in these activities. An exception is seen in children who overuse vision to guide hand use. For these children vision should, at times, be removed from the play activities to encourage the child to retrieve and use haptic information. Haptic object identification is made possible by combining vision and cognition. The use of visual imagery and verbalization helps improve haptic
memory and discrimination. We cannot assume that children will automatically learn cognitive strategies to aid in haptic task performance. For children with attention deficits, brain injury, and mental retardation, the interpretation and use of haptic information might be enhanced by teaching them to use cognitive strategies such as mental imagery or verbalization techniques during task performance. In addition, we know that the ability to identify an object haptically proceeds not only from extracting information from the stimulus or object that is presented, but also by combining “presented information with expectancies based on context or previous experience” (Klatzky & Lederman, 2003),
called top-down processing. Thus providing a cue such as “this is a fruit,” in advance of giving the child an object to manipulate may result in improved performance.
EVALUATION OF HAPTIC PERCEPTION IN INFANTS AND CHILDREN Assessment of haptic perception can be considered from the perspective of standardized versus nonstandardized assessments and also analyzed according to product/process dimensions. Most of the standardized assessments examine the product; that is, the accuracy of haptic perception, and the number of items the child passed. Many of the nonstandardized assessments used primarily for research purposes examine the process, or the way the child approaches a task, and the effect of the nature of the task on haptic style or strategy. There are several standardized assessments to evaluate accuracy of haptic perception The Miller Assessment for Preschoolers (Miller, 1988) includes a stereognosis item that uses common objects for the younger (2- to 4-year-old) children and geometric shape matching for older (3- to 5-year-old) children. Although a specific score is not given for this item, percentile equivalents can be determined from the score sheet. The Sensory Integration and Praxis Tests (SIPT) (Ayres, 1989) make up a 17-test battery that assesses aspects of sensory processing (visual, tactile, vestibularproprioceptive) and praxis. They are standardized on children ages 4.0 to 8.11 years. This battery includes several tests that tap aspects of haptic abilities. The Manual Form Perception (MFP) test, which assesses stereognosis, has two components. The first component is a haptic-visual intermodal matching task in
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which the child feels a geometric shape without the use of vision and points to its visual counterpart from among a set of choices. The second aspect of the test is a haptic-haptic intramodal matching task in which the child feels a geometric shape with one hand and explores a set of five shapes to find its match with the other hand. The MFP test is a complex task that, when used in conjunction with the SIPT, contributes to identification of various problems including haptic perception, form and space perception deficit across sensory systems, problems in visualization, and somatodyspraxia. The haptic-haptic matching component of the test also reflects functional integration of the two sides of the body (Ayres, 1989). In the graphesthesia test (GRA) of the SIPT, the examiner draws a design on the back of the child’s hand and the child must reproduce that design with his or her finger. This is not truly a haptic perception task because the tactile input is received passively not through active manipulation. Nevertheless it is similar to many haptic perception tasks because the child needs to interpret designs received through moving touch applied to the hand and then signify knowledge of the design by a motor response. As with tests of haptic perception, fine motor coordination and motor planning abilities are necessary for optimal test performance (Ayres, 1989). Another standardized test that includes aspects of haptic perception is The Luria-Nebraska Neuropsychological Battery: Children’s Revision (Golden, 1987), a 149-item test battery designed to assess a broad range of neuropsychological functions in children ages 8 to 12 years. There are 11 different scales, one of which assesses tactile functions. The 16 items on this scale assess tactile localization, tactile discrimination, intensity, tactile spatial discrimination, direction of movement, identification of traced shapes and numbers, and identification of objects. The specific items on the Tactile Function Scale that address aspects of haptic perception include two items that assess stereognosis, in which the examiner places an object (quarter, key, paper clip, and eraser) in the child’s hand and the child must name the object. If word-finding difficulties are suspected, the examiner can place the four objects in front of the child along with four other objects and ask the child to point to the object he or she just felt. There are also four items that are similar to the graphesthesia test of the SIPT. In these items the child is required to recognize a cross, triangle, and circle drawn on the back of his or her wrist with a pencil. There are two items in which a number is written on the back of the wrist. In these items the child needs to know only that a number was drawn and need not identify the specific number. An overall score is provided for the Tactile Function Scale. Although there is not a specific score
for the items assessing haptic perception, the examiner can look at performance on these items. The LuriaNebraska Scales usually are administered by a neuropsychologist and, like the Sensory Integration and Praxis Tests, require special training. However, the knowledgeable therapist can use results of this test to aid in evaluation. All the preceding tests examine accuracy of haptic identification. The manipulation strategies used in haptic exploration are not examined. At present there is no standardized examination of exploratory strategies. However, the work of Zaporozhets (see Table 4-2) provides guidelines for the therapist wishing to examine this area. If, for example, a therapist notes that a 7-year-old child is using only grasping to examine complex shapes, he or she can infer that this child is using immature and inefficient strategies to gain information about objects. Exner (1992) developed a test to examine in-hand manipulation in children ages 18 months through 61⁄2 years. Although the emphasis of this work is on the hand as a motor instrument used to accomplish specific skilled fine motor tasks with vision present, the process of adjusting objects within the hand after grasp (in-hand manipulation) is critical to enable effective haptic manipulation to gain perceptual information about an object (Case-Smith & Weintraub, 2002). There are no standardized assessments to examine haptic identification of the material properties of objects such as weight, texture, or object features such as length. Research has indicated that individuals use different strategies to gain information about these object characteristics. For example, if children are asked to match objects on the basis of texture, they use lateral motion; if they are asked to match objects on the basis of hardness or firmness, they use pressure; if they have to match on the basis of shape, they tend to use contour following (Streri, 2003a). In working with children with disabilities, we should examine whether they vary the strategy used in exploring different object properties as do typical children (McLinden, 2004; McLinden & McCall, 2002). Although the typical child does not need or receive specific training in how to use the haptic sense, it may be necessary to explicitly teach haptic manipulation strategies in children with disorders (McLinden & McCall, 2002). For therapists wishing to assess haptic abilities in young infants, the best assessments at present are observational qualitative assessments rather than standardized testing, although it is important to use a standard protocol to compare infants and see change in haptic style over time. It has been reported in the literature that from 6 to 12 months there is a decrease in mouthing and an increase in fingering behavior (Ruff, 1980; Streri, 2003a). Thus if at 12 months an
Perceptual Functions of the Hand • 79 infant is bringing everything to the mouth, one could identify a delay in the use of the hands for manipulation. Similarly, Ruff (1980) noted that 9- and 12-month-old infants adjusted their behavior to the characteristics of objects and more often fingered textured objects with prominent surfaces than smooth objects. Thus one could incorporate giving infants both smooth blocks and blocks with textures and surfaces and observing their response to these different objects. The information on the role of manipulation in haptic perception also provides guidance for evaluation. Along with noting the frequency of mouthing and the integration of vision and haptic senses in object exploration in infancy and early childhood, note the manipulation strategy used during performance on tests of haptic perception. Because the identification of common objects matures by 5 to 6 years and can be accomplished with little to no haptic manipulation, common objects may be useful only for assessing pre–school-age children. Changes in the method of manipulation seen during testing may be a better indication of change in haptic perception than is change in the child’s accuracy score. Expanding our assessment beyond the identification of geometric shapes to include the testing of other tactile properties allows us to look at the maturity and flexibility of manipulation patterns and provides insight into the child’s ability to recognize the scope of sensory properties encountered during daily activities. Examination of whether children vary their strategy as a function of the task demand provides information about the type of information the child receives through his or her haptic sense. When assessing haptic perception in individuals with multiple disabilities, such as visual impairment or visual impairment plus other disabilities, McLinden (2004) and McLinden and McCall (2002) caution against relying only on norm-referenced assessments because children with disabilities have different experiences and often do not develop in the same sequence as typical children. However, they recognize that there are no assessments to assess haptic perception that are standardized for children with disabilities. They recommend considering developmental assessments in conjunction with criterion-referenced procedures and process-oriented approaches, and emphasize that it is critical to examine how children use their sense of touch in naturalistic or functional situations. McLinden (2004) recommends using an “adaptive tasks” approach that identifies the child’s use of or response to touch in daily activities. (See also the Scottish Sensory Centre for a discussion of systematic ways to observe a child’s response to touch for learning.) Finally, in examining haptic perception, it is critical to examine the child’s response or reaction to tactile sensory input because this has a significant impact on
the child’s willingness to explore objects through his or her sense of touch. Children who show sensory defensiveness, such as may be seen in children who were preterm as infants (Case-Smith, Butcher, & Reed, 1998), may be unwilling to use their hands to gain information about the environment (Ayres, 1989). Case-Smith (1991) reported that children with tactile defensiveness and poor tactile discrimination demonstrated less efficiency in in-hand manipulation tasks. Response to touch can be assessed observationally while administering standardized assessments of somatosensory perception such as the SIPT, through assessment of sensory processing using caregiver questionnaires (Brown & Dunn, 2002a,b; Dunn, 1999) or through protocols designed for use with children with disabilities (e.g., Assessing Communication Together) that suggest a structure for observing response to touch (Bradley, 1991 as cited in McLinden & McCall, 2002, p. 89).
HAPTIC PERCEPTION IN CHILDREN WITH DISORDERS PREMATURITY The characteristics of touch most fully explored in the infant are those related to social and emotional functioning, and research on the perceptual role of touch often proceeds separately from research on its social role (Rose, 1990). Recently the specific role of tactile stimulation has been examined, and numerous studies have investigated whether the preterm infant will benefit from changes in the quantity, quality, or patterning of stimulation in the environment (Field, 2002, 2003). The sensory organization and perceptual processing characteristics of the preterm infant also have been investigated. Rose and co-workers (Rose, Schmidt, & Bridger, 1976; Rose et al., 1980) examined the infants’ responsivity to (passive) tactile stimulation and their abilities to discriminate different intensities of such stimulation. Infants were assessed at 40 weeks’ gestational age, and, while sleeping, they were touched with plastic filaments of different intensities and their cardiac and behavioral responses were examined. Results indicated that preterm infants are significantly less responsive to tactile stimulation than are full-term infants. Rose, Gottfried, and Bridger (1978) also examined differences between preterm and full-term infants at 1 year of age in an active touch multimodal (haptic and visual) task using a habituation paradigm. Preterm infants did not show any evidence of cross-modal transfer, whereas full-term infants did show such transfer. These results indicate that full-term infants are
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able to gain knowledge about the shape of an object by feeling it and mouthing it and that they are able to make this information available to the visual system. They were able to do this even after only 30 seconds of handling or mouthing of the object. On the other hand, preterm infants did not seem to know that the object they saw was the same object they were exploring with their hand or mouth. Overall, preterm infants were limited in acquiring information; they showed evidence of difficulty perceiving passive touch and effectively using active touch to explore their world. Interestingly, lower-income full-term infants also showed poorer haptic-visual integration than did full-term middle-income infants. Recognition memory also has been studied in premature infants (Rose, 1983; Rose et al., 1988), who were found to have longer initial exposures and less recovery with novelty, indicating slower and perhaps less complete information processing. Poor haptic perception appears to be long lasting. Two follow-up studies examined the long-term outcomes of children who were born preterm. Somatosensory processing, including haptic perception, was impaired when the children were examined at school age (DeMaio-Feldman, 1994; Short et al., 2003). Another research paradigm that has been found to discriminate between high-risk infants and their typical peers is manipulative exploration. Early studies of exploratory behavior from a Piagetian perspective documented decreased manipulation in premature infants but interpreted the decreased action to be a reflection of a disordered motor system that provided inadequate or inaccurate information (Kopp, 1974). Kopp examined the performance of premature and fullterm 8-month-old infants who were clumsy and nonclumsy (based on reach and grasp). The coordinated group of infants showed significantly more exploration of objects, particularly more mouthing. The infants with poor coordination used more large arm movements and less object manipulation than the infants with good coordination. Kopp discussed the value of object manipulation in enhancing attention and providing information to infants. However, she also pointed out that infants with poor manipulation skills may give extra attention to motor actions, leaving less attention available for sensory or perceptual processing. More recent studies have focused on the attentional and organizational differences between preterm and full-term infants because early focused attention reflects active learning and predicts cognitive outcome (Lawson & Ruff, 2004). Preterm infants exhibit shorter duration of action and less directed information-seeking action. High-risk infants have also been found to have less organized action and attentional strategies in exploratory manipulation of objects (Ruff, 1986; Ruff
et al., 1984). It is not clear whether this disorganization is a purely motor phenomenon or relates to the ability to perceive environmental affordances and act on them.
M ENTAL RETARDATION Research conducted with individuals with mental retardation provides insight into the relationship between haptic perception and cognitive ability. Much of the research examining the relationship among cognitive abilities and haptic manipulation and motor skill has been done with children with Down syndrome (e.g., Brandt, 1996; Moss & Hogg, 1981). These studies generally reported that children with Down syndrome did not show as effective accommodation of their hands to objects after grasp and did not use haptic manipulation and exploratory strategies as readily as typical children. However, it is difficult to directly attribute these results to the child’s cognitive abilities because many of these findings can be attributed to the sensorimotor problems or other aspects of Down syndrome (Exner, 1991). For example, Brandt and Rosen (1995) found that children with Down syndrome demonstrated impaired peripheral somatosensory function (sensory nerve conduction velocities) and suggested that this may contribute to poor tactual perceptual performance. It is likely that, regardless of the cause of the delay, impairment in the ability to efficiently explore objects interferes with learning about key object properties (Exner, 1991). Jones and Robinson (1973) compared the performance of a group of children with mental retardation (mean IQ = 47) to an age-matched group of children with normal intelligence. Accuracy of intramodal (haptic-haptic) and intermodal (hapticvisual) discrimination of meaningless shapes was poorer for the children with mental retardation than for the children with average intelligence. However, other studies found that when children with mental retardation and typical children were matched for mental age, the between-group difference in accuracy of haptic recognition disappeared (Derevensky, 1976, cited in Derevensky, 1979; Jones & Robinson, 1973; Medinnus & Johnson, 1966). In fact, two studies identified subjects with mental retardation as performing better than normal mental age-matched controls in intramodal (haptic-haptic) and intermodal (haptic-visual) matching tasks (Hermelin & O’Connor, 1961; Mackay & Macmillan, 1968). Because matching subjects for mental age eliminated differences in haptic accuracy scores between children with mental retardation and typical children, it can be concluded that some aspects of higher cognitive processing are most likely necessary for task completion. In addition to verbal intelligence, haptic strategies have
Perceptual Functions of the Hand • 81 been found to affect test performance of individuals with mental retardation. Subjects with mental retardation have been known to display immature manipulation strategies during tests of haptic perception. The sophistication of haptic manipulation strategies has been shown to be closely related to cognitive ability because manipulation strategies tended not to differ between typical children and children with mental retardation when subjects were matched for mental age (Davidson, 1985; Davidson, Pine, & WilesKettenmann, 1980). An increase in sophistication of manipulation strategies has been shown to occur in close association with an increase in mental age within the population with mental retardation (Davidson et al., 1980). Evidence from research on children with mental retardation who were blind and sighted and age-matched controls suggests that experience may contribute to improved manipulation and thus accuracy of intramodal (haptic-haptic) matching in individuals with mental retardation, but experience alone cannot fully compensate for the effects of reduced cognitive ability (Davidson, Appelle, & Pezzmenti, 1981). These findings suggest that training can help improve the sophistication of manipulation strategies in individuals with mental retardation, but such improvement in hand function may be only partially effective in improving performance on tests of haptic perception.
BRAIN I NJURY Impairments in tactile perception frequently have been reported in children with a diagnosis such as cerebral palsy that indicates a known brain injury (Bolanos et al., 1989; Boll & Reitan, 1972; Cooper et al., 1995; Duque et al., 2003; Krumlinde-Sundholm & Eliasson, 2002; Reitan, 1971; Solomons, 1957; Tachdjian & Minear, 1958; Van Heest, House, & Putnam, 1993; Yekutiel, Jariwala, & Stretch, 1994) and with traumatic brain injury (Ayres, 1989). Stereognosis (haptic identification of shapes or common objects) is often cited among the tactile functions showing impairment. Intermodal (visual-haptic) matching of shapes also has been shown to be impaired in children with brain injury (Birch & Lefford, 1964). Solomons (1957) found that children with brain injury were also impaired in the haptic discrimination of size and texture, although they did not differ from typical children in their ability to haptically match objects by weight. Although Boll and Reitan (1972) cited no problems in haptic shape recognition, they noted that the children with brain injury performed poorly on a complex tactile performance task that required shape recognition for task completion. Rudel and Teuber (1971) compared the ability of typical children and children with brain injury to discriminate three-
dimensional shapes through the use of intramodal (haptic and visual) and intermodal (visual-haptic) matching. Reduced performance in the group with brain injury was seen only in the visual-visual and visual-haptic matching conditions. These authors noted that, unlike the typical controls, who tended to perform better on the test conditions that included the use of vision than on the one requiring solely the use of touch, the addition of visual cues did not seem to assist the subjects with brain injury to improve their test performance. This finding suggests that children with brain injury may have a problem in visual perception or visual-haptic integration. However, this conclusion should be interpreted with caution because the mental ages of the subjects in the group with brain injury were 11⁄2 to 2 years above that of the control group. It is possible that, if the subjects were more equally matched for mental age, greater impairment in haptic perception might have been found within the group with brain injury. The studies reviewed frequently used children with a mixture of diagnoses (e.g., cerebral palsy, encephalitis, traumatic head injury). Thus it was not surprising to find research that cited deficits in manual dexterity (e.g., finger tapping, grip strength, motor coordination) along with dysfunction in tactile perception in the children with brain injury (Boll & Reitan, 1972; Reitan, 1971). Solomons (1957) compared the ability of children with brain injury with and without fine motor impairment to perform tests of haptic perception. The children with brain injury with intact hand function were able to more accurately match objects by shape, texture, and size than the children with brain injury with fine motor impairment. Studies also have reported that deficits in tactile perception (including stereognosis) have been closely associated with poor hand function in children with cerebral palsy (Duque et al., 2003; Gordon & Duff, 1999; Tachdjian & Minear, 1958). In addition, stereognosis has been identified as a good predictor of upper-extremity surgical outcome within the population with cerebral palsy (Goldner & Ferlic, 1966).
LEARNING DISABILITIES AND RELATED DISORDERS Impairment in tactile perception also has been cited in children who display learning disabilities and related disorders, conditions in which clearly identifiable brain damage has not been found. Poor tactile and kinesthetic perception has been found in children with learning disabilities, language disorders, dyspraxia, autism, and developmental Gerstmann syndrome (Ayres, 1965, 1989; Harnadek & Rourke, 1994; Haron & Henderson, 1985; Johnson et al., 1981; Kinnealey, 1989; Kinsbourne & Warrington, 1963; Lord &
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Hulme, 1987; Spellacy & Barbara, 1978; Nyden et al., 2004), with stereognosis among the tactile tests used in some of these studies. Impairment in motor coordination often has been found to accompany poor tactile perception in children with learning disabilities and related disorders. Johnson and co-workers (1981) found children with language disorders performed more poorly than a group of typical children matched for age, IQ, and socioeconomic status on tests of tactile perception (simultagnosia, graphesthesia, and finger identification) and motor coordination (hopping, finger opposition, diadochokinesis, and putting coins in a box). Reports of children with developmental Gerstmann syndrome have commonly cited a pairing of impairment in finger identification and constructional praxis (including poor handwriting and difficulty drawing geometric shapes) (Benton & Geschwind, 1970; Kinsbourne & Warrington, 1963; PeBenito, 1987; Spellacy & Barbara, 1978). CaseSmith (1995) studied 30 preschool children with perceptual-motor problems and found that stereognosis (Manual Form Perception test of SIPT) correlated with Motor Accuracy, a test of fine-motor skill (r = 0.43). Several other authors also have linked deficits in somatosensory processing (including poor haptic perception) to problems in motor planning (praxis) (Ayres, 1965, 1969, 1971, 1972, 1977, 1989; Ayres, Mailloux, & Wendler, 1987; Gubbay, 1975; Hulme et al., 1982; Reeves & Cermak, 2002; Walton, Ellis, & Court, 1962). However, it is not clear whether impaired haptic perception contributes to poor motor planning, poor motor planning contributes to difficulty in haptic perception, or there is an ongoing interaction. There has been little research specifically designed to identify factors that may be contributing to impaired haptic perception in children.
SUMMARY AND I MPLICATIONS FOR PRACTICE The previous section provides evidence of the existence of problems in haptic perception in children born prematurely and those with a variety of disorders associated with brain injury and learning disabilities. Like much of the literature on haptic perception in children previously discussed, most of the research on haptic perception in children with disorders has been limited to the study of haptic discrimination of shape. The presence of problems in haptic discrimination of shapes does not mean that a child also has equal impairment in haptic discrimination of objects containing other sensory properties (e.g., texture and weight). Thus we cannot assume that because a child has problems discriminating shapes he or she has global impairment in haptic perception. Future research on children with disabilities needs to be directed toward the analysis of
haptic recognition of objects having a variety of sensory properties. Factors contributing to test performance (e.g., in-hand manipulation and attention) also should be addressed if we are to gain the information needed for effective intervention. It was interesting to note that the reduced sophistication of manual and in-hand manipulation strategies, seen with impairments in visual perception and visual-haptic integration were cited as possible contributing factors to poor haptic perception in all the conditions reviewed. Although reduced cognitive ability was considered only in children with mental retardation, attention deficits or related cognitive processing problems were cited as possible contributing factors to impairment in other populations.
SUMMARY Haptic perception in infants and children has been reviewed in depth in this chapter. It was the authors’ intent to provide an overview of the literature on the topic, with emphasis on material relevant to the evaluation and treatment of disorders in haptic perception in children with suspected and identified CNS dysfunction. The literature reviewed provides insight into the development of haptic perception and the identification of factors that may be contributing to impairment in haptic perception in some children. Haptic perception emerges in early infancy and continues to mature into adolescence. The infant initially uses oral exploration to learn about objects. The hands first transport objects to the mouth and later become a primary tool for haptic object exploration. Manual manipulation of objects begins with grasping and is later replaced by more specific manipulation patterns (e.g., fingering, banging) that are tailored to the physical properties of the object. Manual manipulation gradually replaces mouthing as the preferred method of object exploration. This is followed by a long period of development in which the accuracy of haptic object recognition improves and the complexity of manual manipulation and exploratory strategies increases. The accuracy of haptic object recognition is related to the choice of haptic manual manipulation and exploratory strategies. Vision appears to guide the development of manual manipulation and helps to bring meaning to the haptic information being retrieved by the hands. It is not until 6 years of age that children can easily explore objects with the hands without the assistance of vision. With time the hands develop the ability to retrieve information from the environment without the aid of vision, making it possible for vision and haptic sensory processing to take
Perceptual Functions of the Hand • 83 on separate supportive roles in daily function; however, visual imagery continues to be used by many people to aid in haptic object recognition. Research suggests that the ability to use cognitive strategies such as visual imagery and verbalization in the cognitive processing of haptic information develops with age. It appears to be related to intelligence, because there is an association between mental age and the accuracy of haptic object recognition. Review of the literature on haptic perception in children with disorders suggests that impairment in somatosensory processing, manual and in-hand manipulation, vision, visual perception, or cognition can contribute to deficits in haptic perception. Most of the tests currently used to assess haptic perception measure the product, the number of objects identified correctly. Yet process might be as important as, or even more important than, product when using the results of testing to guide treatment. Assessing the process means considering the quality of manual manipulation and exploratory strategies, along with the degree to which vision and cognitive strategies are being used in task performance. Therapists should be aware that the tests available to measure haptic perception in children assess only a segment of this function. Because a child shows impairment in shape recognition on a test of stereognosis does not mean that the same child will display problems in haptic discrimination of other sensory properties (e.g., weight, texture). We should consider developing tests of haptic perception that assess the breadth of haptic sensory properties found in objects. We also should develop tests that measure the process, as well as the product of task performance. We should test haptic discrimination of several sensory properties to determine the extent of dysfunction, and we should analyze the process of task performance to determine the reason for low test scores. We also should develop treatment strategies that will translate into improvement in the use of haptic perception in daily function.
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Chapter
5
REACHING AND EYE-HAND COORDINATION Birgit Rösblad
CHAPTER OUTLINE MATURE REACHING MOVEMENTS Movement Speed Transport and Grasp Phase Role of Vision Role of Proprioception Integration of Sensory Information
around the ball before the moment of contact, or we will fail to catch it. In other types of goal-directed arm movements the arm trajectory as such can be the goal, as when painting or drawing, but in a reaching movement the goal is to transport the hand to the target, with precision in both time and space. This chapter is organized in three parts: the first deals with the mature reaching movement, the second with the development of reaching in infancy, and the third with reaching in children with motor disabilities.
DEVELOPMENT OF REACHING DURING INFANCY Beginning to Master the Reach Coordinating the Body Parts Involved in the Reaching Movement
MATURE REACHING MOVEMENTS
Movement Planning
Reaching for an object means getting the hand from a starting position to the goal, the object. In doing this, the hand describes a trajectory. The word trajectory can be used in different ways, but here refers to the path taken by the hand as it moves toward a target and the speed as it moves along the path. The reaching trajectory has several characteristics that are discussed later.
Role of Sensory Information Movement-to-Movement Variability REACHING IN CHILDREN WITH MOTOR IMPAIRMENTS Movement Planning Feedback Control of Reaching Movements Adaptation of Reaching Movements The Movements of the Arms Are Coupled in Children with Hemiplegic Cerebral Palsy Our hands are extremely important tools for us in our everyday lives, and we are able to use them with grace and skill. To do so we have to be able to bring them to the right place at the right time. This can be illustrated with the example of catching a ball. To catch the ball successfully the hand has to be at the calculated meeting point at exactly the right time. Moreover, it must be prepared for the catch, with the fingers closing
MOVEMENT SPEED If the velocity of the hand during a reaching movement is plotted versus time as in Figure 5-1, one can see that the tangential velocity curve is bell shaped. The reaching movement is continuous with one single peak of velocity. In the last part of the reaching movement, when the hand is close to the target, the velocity is slow. This typical bell-shaped velocity curve is seen when the reach is carried on with, as well as without, visual feedback (Jeannerod, 1984; Morosso, 1981). This indicates that the reaching movement is programmed in advance of movement onset to a high degree.
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cm/s2
cm/s
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ms Figure 5-1 Kinematic profiles of the transport component of a reaching movement. The heavy line depicts the velocity of the wrist (cm) as a function of time. This curve describes a single continuous movement with a single peak of velocity. The two peaks connected by the thin line depict the acceleration of the wrist (cm2) as a function of time. The positive peak constitutes one phase of acceleration and the negative peak one phase of deceleration, together forming one movement unit. (From Jeannerod M, et al. [1992]. Parallel visuomotor processing in human prehension movements. In R Caminiti, PB Johnson, Y Burnod [editors]: Control of arm movement in space. New York, Springer-Verlag.)
If one considers the reaching movement in terms of accelerations and decelerations, it can be divided into movement units. One phase of acceleration followed by a deceleration then can be said to constitute a movement unit (Brooks, 1976; von Hofsten, 1979). The movement paths within these movement units are relatively straight, and movement direction is changed in between units (von Hofsten, 1991). The number of movement units comprising a movement can be viewed as an index of its degree of programming. A movement consisting of only one movement unit, such as that depicted in Figure 5-1, then can be viewed as being entirely programmed before movement onset. However, if the movement is composed of many movement units, one can assume that it has been programmed several times during execution. A reaching movement, aimed at a stationary object, generally consists of one or two movement units, with the first covering the main part of movement duration. The choice of movement speed is crucial for how skillfully we manage to reach and grasp an object. A movement cannot be both fast and precise. Unconsciously we strive to optimize movement speed to suit
the activities we perform. When we reach out to pick a blueberry, movement speed is lower compared with that used in reaching for a ball we intend to throw. The decrease of accuracy when speed increases has been called the “speed-accuracy trade-off ” and is defined by Fitts’ law (1954). The minimum variance theory, put forward by Harris and Wolpert (1998), might explain this phenomenon. They argue that neuronal signals are corrupted by “noise” that increases with the size of the control signal. Therefore increased acceleration leads to increased variability in the final limb position and thus requires further corrective movements. This means that moving very fast can be counterproductive.
TRANSPORT AND G RASP PHASE Another way of viewing the reaching movement is to look for its functional components. Two distinct and coordinated movement components then can be identified (Jeannerod, 1984). The first component is a transportation phase, which brings the hand to the target. In this part of the movement mainly the proximal joints and muscles are involved. The second component is a grasp phase in which the hand is shaped in anticipation of contact with the object. This phase involves mainly the distal joints and muscles. One also can divide the visual information needed to successfully grasp an object into two categories. For the transport phase of the movement knowledge of the position of the object in the room is needed (the object’s extrinsic properties). With this information we can program the direction and extent of the movement. For the grasp phase, perception of the size and shape of the object is needed (the object’s intrinsic properties). There is evidence for independent planning of the two reaching phases (Loukopoulos, Engelbrecht, & Berthier, 2001). Although the grasp and transportation phase of the reach are separately controlled, these two components are coordinated so that the grasp phase starts during the transportation phase. To accomplish a smooth and coordinated grasp, the fingers must initiate the grasp well before encountering the object. Closing the hand too early or too late prevents capturing or makes the grasp impossible or awkward. During the transportation phase the fingers open to a maximum grip aperture. After this maximum opening the fingers start to close in anticipation of contact with the object (Jeannerod, 1981). The control strategy used by the central nervous system to coordinate these components remains largely unknown. However, it has been suggested recently that a simple spatial relation, based on the size of finger opening in relation to finger closing, might determine at what point during the reach the maximum grip aperture will occur (Mon-Williams & Tresilan, 2001).
Reaching and Eye-Hand Coordination • 91 The action we perform shapes our reaching or grasping movement. A small object requires longer reaching time than a larger object. The first part of the movement trajectory seems to be unaffected by object size, but for smaller objects extra movement time is spent in the last part of the movement, after peak acceleration. Moreover, the greater the precision required, the earlier the hand will anticipate the physical characteristics of the object (Marteniuk, MacKenzie, & Athenes, 1990). The hand opens more fully during the reach when reaching for a larger object, and always more than necessary (von Hofsten & Rönnquist, 1988). If the reach has to be carried out with high speed, the grip aperture is larger. Opening the hand more fully during a fast reach could be seen as a way of making sure that the object is successfully grasped despite the decreased movement accuracy (Wing, Turton, & Fraser, 1986).
ROLE OF VISION It is obvious that vision plays a very important role in our ability to reach out for objects. One need only imagine what it would be like to be blind to realize the importance of vision to reaching. Vision is the sense that provides us with information about the layout of the environment, and when reaching for an object, vision defines both the position and shape of the object. Seeing the environment gives us an opportunity to anticipate upcoming events and plan our movements in an anticipatory fashion. One example of this is the way we shape our hand before contact with an object. A blind person reaching for an object does not have this ability but has to touch the object first and then, guided by haptic information, shape the hand for grasp. If we cannot foresee upcoming events and plan our movements ahead of time, our movements will be uncoordinated of necessity. Given that visual information is important both for movement planning and execution, one may ask what should be seen and when during the movement we need that information. The answer to this seems to be that full visual information is optimal. Several studies show that we must be able to see the target both before and during a movement or movement quality is reduced (Berthier et al., 1996; Sarlegna et al., 2003). Moreover, if we can see our hand as we move it toward the target, movement accuracy and efficiency will be improved (Connolly & Goodale, 1999; Sarlegna et al., 2004; Saunders & Knill, 2003; Schenk, Mair, & Zihl, 2004). The minimum delay needed for visual information to affect the physical movement of the hand traditionally has been thought to be around 200 msec (Keele & Posner, 1968). Because many naturally occurring reaching movements take around 500 msec to com-
plete, the assumption has been that only low-velocity movements can be influenced by visual feedback. However, there is now considerable evidence that visual feedback might be as fast as 160 to l00 msec, and that we use online visual information to correct both slow and fast movements (Alstermark et al., 1990; Martin & Prablanc, 1992; Paulignan et al., 1991a,b; Saunders & Knill, 2003). Nevertheless, even if the movement is carried out without visual feedback, the main features of the reaching trajectory remain. One will still see the bellshaped velocity curve, as well as the coordination between movement speed and anticipatory hand shaping (Jeannerod, 1981). This indicates that to a high degree the reaching movement is programmed in advance of movement onset but can be modified during execution when necessary—that is, when endpoint accuracy is needed or if we reach for a target that moves in an unpredictable way.
ROLE OF PROPRIOCEPTION We have receptors in our muscles, tendons, joints, and skin that provide us with information about the positions and movements of our body parts. This is here termed proprioception, after Sherrington (1906). Although it is relatively easy to find out how we can move without vision or with degraded vision, proprioceptive information cannot be manipulated as easily. Instead, the research on the role of proprioception has focused on animal experiments and patients with sensory loss caused by diseases. One line of research has used deafferented monkeys. When their dorsal spinal roots are sectioned, the monkeys are deprived of sensation from the upper limbs but the motor nerves are unaffected. This technique was used in early experiments by Mott and Sherrington (1895). They reported that the monkeys’ limbs became useless after such operations and that the animals used their upper limbs only if forced to and then in an awkward way. They concluded that afferent information from the limbs was necessary for both movement initiation and control. Similar results also were reported by Lassek & Moyer (1953). However, later experiments with deafferented monkeys reported different results. Taub and Berman (1968) reported a clear improvement in motor function after the initial disability that resulted from the section of the nerves. The animals were able to reach for and grasp objects with a primitive pincer grip a few months after surgery. Recovery of function also has been reported by Knapp and co-workers (1963). Bossom and Ommaya (1968) have pointed out that motor pathways can be damaged easily during a rhizotomy and that this could be why the degree of recovery of function varied between studies.
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Despite the previous diversity in results, there are also similarities. Several investigators have found that, when forced to, the animals are able to use their deafferented limb. Animals that had both forelimbs deafferented regained function to a higher degree than those with only one deafferented forelimb, who could choose to use the normal hand. This latter effect has been called learned nonuse by Taub and Berman (1968) and was explained in terms of an inhibition of the deafferented limb. However, if the animals that had one limb deafferented were forced to use it because the normal limb was restrained, they recovered function to the same degree as the bilaterally deafferented animals (Bossom, 1974; Knapp et al., 1963). Yet another similarity among the reports is that the deafferented monkeys were capable of both initiating and carrying out motor acts, however uncoordinated. Studies of humans with sensory deficits seem to confirm this. Gordon and Ghez (1992) described patients with large-fiber sensory neuropathy in the following way: “These patients, although able to initiate and carry out complex movement sequences, were severely impaired in most functional activities. For example, none could drink water from a cup without spilling.”
The experiments by Ghez and co-workers (1990) provide us with important information about the role of proprioception in reaching movements. They studied the reaching movement in patients with sensory loss caused by large-fiber neuropathy. Without visual feedback the patients made large directional errors from movement onset and also were unstable at movement endpoint. When allowed to monitor the movement visually, they were able to substitute for the loss of proprioceptive information to some degree, and performance improved. However, Ghez and coworkers (1990) also studied the effect on movement accuracy when the patients were able to look at the limb before movement onset but not during the ongoing movement and found that this also improved function. This indicates that proprioception is not only important for feedback during the ongoing movement but also plays an important role for programming of movements by providing the nervous system with information about the current state of the body parts.
I NTEGRATION OF SENSORY I NFORMATION When we reach for an object both vision and proprioception provide information about hand position, and this information must be integrated to generate one single estimate of where the hand is in space (van Beers, Wolphert, & Haggard, 2002). This means that
the visual and proprioceptive systems have to be in correspondence with each other. One example of when they are not integrated involves wearing a pair of displacing prisms. If we then reach for an object, we perceive the object at a location displaced from its virtual position, and the reach is directed to this erroneous position. However, reaching actively toward the object several times rapidly reintegrates the visual and proprioceptive systems, and within a few minutes adaptation has occurred (Harris, 1965). This also can be experienced when one puts on a pair of new glasses. The distance to the ground seems to be changed, and it takes some minutes of walking before the visual system again is in agreement with the proprioceptive system. A recent study by van Beers and co-workers (2002) suggests that the extent to which vision and proprioception contribute to the control of reaching movements depends on the task. The brain weighs the information from each modality in a way that minimizes the uncertainty in perceived position. This suggests that we cannot say that one modality dominates the other and that the situation is better described as a flexible weighing of information from the modalities to obtain movement precision.
DEVELOPMENT OF REACHING DURING INFANCY BEGINNING TO MASTER THE REACH Observing a newborn baby’s arm movements, one might perceive them as random, performed without meaning. However, even at birth the infant is capable of movements that require some degree of sensory motor integration. Von Hofsten (1982) placed 5-day-old infants in a semireclining seat that gave good support to the trunk and head but allowed free movement of the arms. The infants were presented with a colorful tuft that moved irregularly and slowly in front of them. The infants’ arm movements were recorded with two video cameras, making it possible to calculate the arm trajectory in three-dimensional space. All infants noticed the tuft and were able to follow it with eye and head movements for varying periods. The infants’ forward extended arm movements, as well as looking behavior, were analyzed. When the infants were fixating the tuft, they aimed their reaching movements closer to it than when looking in another direction or closing their eyes. Thus a child only a few days old already has a rudimentary visual control of arm movements. Moreover, when initiating an aimed movement toward a visually fixated target, the infant must “know” where its arm is.
Reaching and Eye-Hand Coordination • 93 Because the neonate is fixating the target, the starting position of the hand must be defined proprioceptively. This indicates that the visual and proprioceptive spaces are to some degree already connected in the newborn infant. However, even though the infants aimed their reaching movements closer to the object while fixating on it, most of the time they did not touch it. Also, at this early age, even if they did touch the object, they were not capable of grasping it. Several months of experience of its the own body and with the environment still remain before the infant starts to become successful at reaching, at around 4 to 5 months of age (Gesell & Ames, 1947).
COORDINATING THE BODY PARTS I NVOLVED IN THE REACHING MOVEMENT Before the infant can reach for and grasp an object he or she must learn to coordinate the movements of the shoulder, arm, and hand. This complicated task of controlling movements over several joints, and accordingly a great number of movement possibilities, has been designated as the degrees of freedom problem (Bernstein, 1967). One solution to this problem is to reduce the degrees of freedom by keeping some of the involved joints in a stiff position. This also seems to be the strategy used by infants as they first start to reach for objects. Berthier and colleagues (1999) found that beginning reachers mainly use shoulder and torso rotation to move the hand to the target, while the elbow is kept in a stiff position. This reduces the complexity of the movement and thus increases the infant’s chances of successfully capturing the object. However, an obvious limitation of this strategy is that it restricts the infant’s possibility of placing the hand in an optimal position for grasping. Postural stability is yet another foundation for reaching movements. Van der Fits and colleagues (1999), who studied postural adjustments during arm movements in infants, found that when infants first start to reach successfully for objects the arm movements are accompanied by a large amount of postural activity. Already at this young age the pattern of activation showed some resemblance to that seen in adults, with an activation of the dorsal muscles before the ventral and a top-down recruitment of muscles. With increasing age the pattern of activation became more organized. Yet another study demonstrating the linkage between the development of posture and reaching was carried out by Rochat (1992). When the infants started to reach for objects, they tended to use both hands and later in development acquired one-handed reach. A successful object-oriented reach in a young infant is symmetric and synergistic with the hands meeting in
midline. Older infants often display an asymmetric onehand reach. He reported that when infants first attained the ability to sit without support they shifted toward reaching more with one hand so that the other could be used to maintain balance. Hopkins and Rönnqvist (2002) studied reaching behavior in infants aged about 6 months who were not yet able to sit without support. They compared the quality of the reaching movements when the infants were provided with firm postural support and when they were sitting in a commercially available chair. That the firm postural support resulted in a decrease in the number of movement units indicates that this extra support improved the reaching behavior. Clinical observations made by Grenier (1981) also indicate that postural control is important for coordinated arm movements and that if infants are supported appropriately at the neck and trunk they can perform coordinated arm movements at a much earlier age than is typical. Postural control does not only act by maintaining balance after it has been perturbed. We also have the ability to anticipate an upcoming situation that will perturb our balance and prepare ourselves by means of postural adjustments. There is some evidence that this anticipatory mode of counteracting upcoming forces on the body starts to operate during the first year of life. Von Hofsten and Woollacott (1989) showed that at 10 months of age children activated the muscles of the trunk before making voluntary arm movements. The integration between posture and voluntary control is an important prerequisite for coordinated arm and hand movements. Little is known of how children with motor impairments can integrate voluntary movements and posture, but it is possible that this is one contributory factor in these children’s fine motor disturbances.
MOVEMENT PLANNING As discussed, the reaching movement can be analyzed in terms of acceleration and deceleration. A phase of acceleration followed by a phase of deceleration then constitutes a movement unit. When the infants first start to reach and grasp, at around 4 months of age, the ability to plan the movement ahead of time is still poor. As a consequence of this, the movement path is awkward and crooked, and the trajectory consists of many movement units. This changes after the infant has practiced reaching for some time, and at around 1 year of age the number of movement units has decreased and the movement paths are straighter (Konczak & Dichgans, 1997; von Hofsten, 1991) (Figure 5-2). The ability to plan movements ahead of time, and not only react to what has already happened, is fundamental for movement skill. One example when this is
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Figure 5-2 Sagittal hand paths of one infant at four different ages illustrating the progression toward smoother and straighter movements. (From Konczak J, Dichgans J (1997). The development toward stereotypic arm kinematics during reaching in the first 3 years of life. Experimental Brain Research, 117:346–354.)
obvious is when we catch a ball that is thrown to us. To be able to do this we must predict the trajectory of the moving object and reach for the meeting point. Von Hofsten and Lindhagen (1979) found that at the age children start to reach successfully for stationary objects, they also can catch fast-moving ones. Eighteenweek-old infants were found to be able to catch objects that moved at 30 cm/sec. Most of the reaches were aimed at the meeting point from movement onset. This demonstrates an early emerging capacity for anticipatory control of reaching movements. That is, the infant does not reach toward where he or she first sees the object, but rather appears to be anticipating the point where the hand and the object will meet (Figure 5-3). The ability for anticipatory control develops substantially during the first year of life. One example of this is how the infant prepares the hand for the grasp. An adult reaching for an object shapes the hand to fit the properties of the object in anticipation of contacting it. Von Hofsten and Rönnquist (1988) studied the shaping of grip aperture as infants reached for objects. The 5- to 6-month-old children started to close the hand before making contact with the object, which indicates some anticipatory ability. However, these young infants did not adjust their grip aperture to match the object size, as did children at 9 months of age. At 13 months of age the infants started to close the hand earlier during the reach compared with the younger children and were comparable to adults in this respect. Infants 10 months of age also have been found to shape their hand to fit different shapes of objects before contact (Pieraut-Le Bonniec, 1990).
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Figure 5-3 Two views of the performance of a wellaimed reach by an infant who is 21 weeks of age. The frame on the bottom is the start of the reach. The interval between frames is 0.2 sec (digital clock reading in the upper portion of each frame). The child is directing the reach ahead of the object to the point at which the object will be at the end of the reaching movement. (From von Hofsten C [1980]. Predictive reaching for moving objects by human infants. Journal of Experimental Child Psychology, 30:369–382.)
When we as adults reach for an object the movement trajectory is not only affected by the size and shape of the object but also by what we intend to do with it after we have picked it up. We reach more slowly for an object that will be used in a precision task (e.g., fitting a coin in a slot) than for an object that will be used in a nonprecision task (e.g., throwing the coin in a bucket). Claxton, Keen, and McCarty (2003) studied 10-month-old infants to see if they also had this ability to plan a reaching movement in several segments. The
Reaching and Eye-Hand Coordination • 95 infants were encouraged to reach for a ball and then either throw it into a tub or fit it into a tube. Infants, like adults, reached for the ball faster if they were going to throw it as opposed to fit it into the tube. This shows that infants have an ability to take several steps into account when planning an activity. However, they did not show the more sophisticated signs of movement planning that adults do, such as a prolonged deceleration phase when reaching for an object that will be used in a precision task.
discussed in the preceding section suggest that young infants are able to use proprioceptive information and integrate it with visual information when reaching for objects. A similar result was found when reaching was studied in children 6, 7, and 8 years of age, in a situation in which the amount of visual information was varied. The children seemed to use visual information for control of arm movements in a manner similar to that of adults, although with less accuracy and speed (Rösblad, 1998).
ROLE OF SENSORY I NFORMATION
MOVEMENT-TO-MOVEMENT VARIABILITY
As discussed, visual information of the hands as well as the goal is necessary for movement accuracy. However, to a great extent we are able to replace visual information with proprioceptive and tactual information if the hand for some reason is out of sight or if we reach in the dark. Clifton and colleagues (1994) have in a series of studies investigated the ability in infants to reach for objects in the dark They showed that 6- to 7-month-old infants could contact sounding objects (Perris & Clifton, 1988) and that infants of 6 months could successfully reach for glowing objects (Clifton et al., 1994) and also reach for glowing objects that were moving in the dark (Robin, Berthier, & Clifton, 1996). For many years it has been assumed that young infants are more dependent on visual information for control of reaching movements than adults, and that their ability to use proprioceptive information for movement control is poor (Piaget, 1952). However, the studies
The infant has not yet learned the most efficient way of performing a movement and is still exploring the possibilities of its own body. Therefore he or she will perform a specific task, such as reaching for a toy, with significant movement-to-movement variability. In fact, being able to perform a specific task in a consistent manner is a prominent feature of movement skill. Figure 5-4, A shows the superimposed movement trajectories of a 1-year-old girl reaching for an object. In Figure 5-4, B the same task is performed by an 11year-old boy. Although the little girl grasps the object without difficulty, it is clear that she does not reach for the object with the same skill as the older boy does. Lhuisset and Proteau (2004), who studied reaching movements in children 6, 8, and 10 years old, found that although the children clearly planned the movements ahead of time, the planning processes were still more variable than for adults.
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Figure 5-4 The figures show that a young child performs a specific movement with high variability, whereas an older child has a more consistent movement pattern. A, Trajectory of the hand for a 12-month-old girl who is reaching repeatedly for the same object. B, How an 11-year-old boy performs the same movement. (From Eliasson AC, Rösblad B [2001]. Arm och handrörelser: Normal och avvikande utveckling. In E Beckung, E Brogren, B Rösblad [editors]: Sjukgymnastik för barn och ungdom. Teori och tillämpning. Lund, Studentlitteratur.)
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REACHING IN CHILDREN WITH MOTOR IMPAIRMENTS We still have limited knowledge concerning the ability to plan and control reaching movements in children with motor impairments. However, the knowledge we have from research carried out on normally developed children and adults can be used when asking questions about children with motor impairments. This section provides examples from this line of research.
MOVEMENT PLANNING A common finding in motor control research on children with motor impairments is that the ability for movement planning is impaired. One example of how the ability to plan reaching movements can be impaired comes from a study on reaching in children with attention deficit hyperactivity disorder (ADHD) (Eliasson, Rösblad, & Forssberg, 2004). To analyze the kinematics of the arm movement we used a digitizing tablet. The task for the children was to move a cursor on a computer screen with a hand-held digitizer on the tablet. Start and target positions on the screen were always visible during the movement. The screen cursor, however, could either be visible throughout the entire movement or blanked at movement initiation. Analysis showed that movement control was impaired in children with ADHD and that their problems were especially pronounced when the screen cursor was not visible on the screen. Because the children could not visually correct the movement when the screen cursor was blanked, results indicate a poorer motor programming in children with ADHD. Moreover, the children with ADHD performed jerky movements with higher peak accelerations than the control group of children. As discussed earlier in this chapter, the choice of movement speed is crucial for how skillfully we manage to reach for and grasp an object. The children with ADHD adopted higher movement speed compared with the typically developed children but this high speed was counterproductive and resulted in increased movement endpoint errors and further corrective movements. Similar results also have been found when the control of reaching movements in children with developmental coordination disorder (DCD) has been studied. Van der Meulen and colleagues (1991a,b) tested the ability in children with DCD to make precise arm movements. In a first study, the task for the child was to reach for a target as quickly and precisely as possible. In a second study, the ability to track a target that moved unpredictably was assessed. In both studies, the children were tested in situations in which they did or
did not receive visual feedback of the moving arm. Movement analysis indicated that the less efficient movements of the children with DCD could be explained by a less developed ability for anticipatory control.
FEEDBACK CONTROL OF REACHING MOVEMENTS Although it is a common finding that children with motor impairments show signs of impaired ability for movement planning, there are several exceptions to this. We studied the ability of children and young adults with myelomeningocele (MMC) to control reaching movements (Norrlin, Dahl, & Rösblad, 2004). As in the study on children with ADHD discussed in the preceding section, we used a digitizing tablet linked to a computer. Results showed that the ability to program reaching movements was similar in individuals with MMC and a control group of children. In both groups the velocity profiles were bell-shaped and also scaled proportionally to target distances, indicating efficient movement planning. The movement problems in the MMC group seemed to be related to the execution of the ongoing movement. The subjects with MMC showed more problems when they were provided with visual feedback during the entire movement, and thus being given the opportunity to make visual corrections of the trajectory. This suggests that the commonly occurring visual perceptual problems in individuals with MMC may contribute to their poor spatial movement precision. Kearney and Gentile (2002) performed a small but interesting study, on prehension in young children with Down syndrome. They compared the performance of 3-year-old children with Down syndrome (only three children were included) with 2- and 3-year-old typically developed children. The children with Down syndrome scaled the peak velocity to movement distance, which indicates ability for movement planning. However, they differed from both groups of typically developed children in that they performed the final part of the reaching movement with reduced efficacy, which indicates that these children mainly have problems with feedback control of the reaching movement.
ADAPTATION OF REACHING MOVEMENTS Our sensory motor system is highly adaptable. When we use a computer mouse we get used to the specific gain of that mouse and take this into account when we program the movements of hand that will transfer the mouse. If the gain of the mouse is changed we will under- or overshoot the target on the computer screen, but only a few times. The nervous system modifies the
Reaching and Eye-Hand Coordination • 97 programming of subsequent movements to prevent errors and motor adaptation occurs rapidly. Motor adaptation involves changes in the control of movements and can be seen as short-term learning. In everyday life we rapidly and frequently adapt our movements to changing conditions, such as when we switch to new cars with different transmission in the steering system or simply when we switch to a light hammer after having used a heavy one. Again, using the described experimental setup with a digitizing tablet linked to a computer, we investigated the ability in subjects with MMC to adapt reaching movements to a new visuomotor gain (Norrlin & Rösblad, 2004). This was done by first letting the subjects perform reaching movements at targets displayed on a computer screen. After having performed a number of trials (around 100) we changed the gain of the mouse. Directly after this gain change both the children or youths with MMC and the typically developed children overshot the target. However, within a few trials the control group of children had adapted to the new condition and performed movements of the same accuracy as before the change. However, the subjects with MMC needed considerably more time for short-term learning to occur and they had still not fully adapted after 30 trials with the new gain. However, when an unexpected gain change back to the initial condition was introduced after these 30 trials, both groups undershot the target. This indicates that some adaptation had occurred also in the children with MMC. More knowledge about the capacity for motor learning in children with motor impairments, as well as knowledge about the best conditions for learning, would be of great value when planning interventions.
THE MOVEMENTS OF THE ARMS ARE COUPLED IN C HILDREN WITH H EMIPLEGIC C EREBRAL PALSY A specific problem faced by children with hemiplegic cerebral palsy is that the movements of the arms and hands often are coupled. If the child is engaged in manual activities with one hand mirror movements frequently can be observed in the other hand. Typically, reaching movements in children with hemiplegia are performed with lower velocity in the impaired arm than in the unimpaired arm (Van Thiel & Steenbergen, 2001; Volman, Wijnroks, & Vermeer, 2002a,b). However, symmetric movements of the arms tend to improve the movement quality of the impaired hand, measured as speed and smoothness, but restrict the movements of the unimpaired hand, which adapts to the impaired one and accordingly moves more slowly (Utley & Sugden, 1998; Van Thiel & Steenbergen,
2001; Volman et al., 2002a). If the arms and hands are to make asymmetric movements, the movement control problems are amplified. A commonly occurring situation is that we reach out for and grasp an object with one hand while the other hand is occupied with holding another object. The effect that the mirror movements may have on the quality of reaching movement is yet to be investigated. When discussing results from studies of children with motor impairments, we point out that the variation within one specific diagnostic group is large. The movement problems within one diagnostic group could not be explained by one specific factor; however, the knowledge obtained from studies carried out on both normally developed children and children with motor impairments can provide us with knowledge about which processes might be disturbed and what to look for when assessing children.
REFERENCES Alstermark B, Gorska T, Lundberg A, Petterson L-O (1990). Integration in descending motor pathways controlling the forelimb in the cat. 16. Visually guided switching of target-reaching. Experimental Brain Research, 80:1–11. Bernstein N (1967). The coordination and regulation of movement. London, Pergamon Press. Berthier NE, Clifton RK, Gullapalli V, McCall DD, Robin D (1996). Visual information and object size in the control of reaching. Journal of Motor Behavior, 28:187–197. Berthier NE, Clifton RK, McCall DD, Robin DJ (1999). Proximo distale structure of early reaching in human infants. Experimental Brain Research, 127:259–269. Bossom I (1974). Movement without proprioception. Brain Research, 45:285–296. Bossom I, Ommaya AK (1968). Visuomotor adaptation to prismatic transformation of the retinal image in monkeys with bilateral dorsal rhizotomy. Brain, 91:161–172. Brooks VB (1976). Some examples of programmed limb movements. Brain Research, 71:38–47. Claxton LJ, Keen R, McCarty ME (2003). Evidence of motor planning in infant reaching behavior. Psychological Science, 14:354–356. Clifton R, Rochat P, Robin DJ, Berthier NE (1994). Multimodal perception in the control of infant reaching. Journal of Experimental Psychology: Human Perception and Performance, 20:876–886. Connolly JD, Goodale MA (1999). The role of visual feedback of hand position in the control of manual prehension. Experimental Brain Research, 125:281–286. Eliasson A-C, Rosblad B, Forssberg H (2004). Disturbances in programming goal-directed arm movements in children with ADHD. Developmental Medicine in Child Neurology, 46:19–27. Fitts PM (1954). The information capacity of the human motor system in controlling the amplitude of movement. Journal of Experimental Psychology, 47:381–391. Gesell A, Ames LB (1947). The development of handedness. Journal of Genetic Psychology, 70:155–175.
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Ghez C, Gordon I, Ghilardi MF, Christakos CN, Cooper SE (1990). Roles of proprioceptive input in the programming of arm trajectories. Cold Spring Harbor Symposia on Quantitative Biology, 55:837–847. Gordon I, Ghez C (1992). Roles of proprioceptive input in control of reaching movement. In H Forsberg, H Hirschfeldt (editors): Movement disorders in children. Medicine and Sport Science. Basel, Karger. Grenier A (1981). “Motoricite libelree” par fixation manuelle de la nuque au cours de premieres semaines de la vie. Archives Francaises de Pediatrie, 38:557–561. Harris CH, Wolpert DM (1998). Signal-dependent noise determines motor planning. Nature, 394:780–784. Harris CS (1965). Perceptual adaptation to inverted, reversed and displaced vision. Psychological Review, 72:419–444. Hopkins B, Rönnqvist L (2002). Facilitating postural control: Effects on the reaching behavior of 6-month-old infants. Developmental Psychobiology, 40:168–182. Jeannerod M (1981). Intersegmental coordination during reaching at natural visual objects. In I Long, A Baddeley (editors): Attention and performance. IX. Hillsdale, NJ, LEA. Jeannerod M (1984). The timing of natural prehension movements. Journal of Motor Behavior, 16:235–254. Kearney K, Gentile AM (2002). Prehension in young children with Down syndrome. Acta Psychologica, 112:3–16. Keele SW, Posner MI (1968). Processing visual feedback in rapid movement. Journal of Experimental Psychology, 77:155–158. Knapp HD, Taub E, Berman AI (1963). Movements in monkeys with deafferentated forelimbs. Experimental Neurology, 7:303–315. Konczak J, Dichgans J (1997). The development toward stereotypic arm kinematics during reaching in the first 3 years of life. Experimental Brain Research, 117:346–354. Lassek AM, Moyer EK (1953). An ontogenetic study of motor deficits following dorsal brachial rhizotomy. Journal of Neurophysiology, 16:247–251. Lhuisset L, Proteau L (2004). Visual control of manual aiming movements in 6- to 10-year-old children and adults. Journal of Motor Behavior, 36:161–172. Loukopoulos LD, Engelbrecht SE, Berthier NE (2001). Planning of reach-and-grasp movements: Effects of validity and type of object information. Journal of Motor Behavior, 33:255–264. Marteniuk RG, MacKenzie CL, Athenes S (1990). Functional relationships between grasp and transport components in a prehension task. Human Movement Science, 9:149–176. Martin O, Prablanc C (1992). Online control of hand reaching at undetected target displacements. In GE Stelmach, I Requin (editors): Tutorials in motor behavior: II, Amsterdam, Elsevier. Mon-Williams M, Tresilan JR (2001). A simple rule of the thumb for elegant prehension. Current Biology, 11:1058–1061. Morosso P (1981). Spatial control of arm movements. Experimental Brain Research, 42:223–227. Mott FW, Sherrington CS (1895). Experiments upon the influence of sensory nerves upon movement and nutrition of the limbs. Proceedings of the Royal Society, B57:481–488. Norrlin S, Dahl M, Rösblad B (2004). Control of reaching movements in children and young adults with
myelomeningocele. Developmental Medicine and Child Neurology, 46:28–33. Norrlin S, Rösblad B (2004). Adaptation of reaching movements in children and young adults with myelomeningocele. Acta Paediatrica, 93:922–928. Paulignan Y, MacKenzie C, Marteniuk R, Jeannerod M (1991a). Selective perturbation of visual input during prehension movements. 1. The effect of changing object position. Experimental Brain Research, 83:502–512. Paulignan Y, Jeannerod M, MacKenzie C, Marteniuk R (1991b). Selective perturbation of visual input during prehension movements. 2. The effect of changing object size. Experimental Brain Research, 87:407–420. Perris EE, Clifton RK (1988). Reaching in the dark toward sound as a measure of auditory localization in infants. Infant Behavior and Development, 11:473–491. Piaget J (1936/1952). The origins of intelligence in children. New York, Norton. Pieraut-Le Bonniec G (1990). Reaching and hand adjusting to target properties. In H Hloch, HI Hertenthal (editors): Sensory-motor organization and development in infancy and early childhood. Netherlands, Kluwer. Robin DJ, Berthier NE, Clifton RK (1996). Infants’ predictive reaching in the dark. Developmental Psychology, 824:835. Rochat P (1992). Self-sitting and reaching in 5- to 8month-old infants: The impact of posture and its development on eye-hand coordination. Journal of Motor Behavior, 24:210–220. Rösblad B (1998). Roles of visual information for control of reaching movements in children. Journal of Motor Behavior, 29:174–182. Sarlegna F, Blouin J, Bresciani J-P, Bourdin C, Verchr J-L, Gauthier GM (2003). Target and hand position information in the online control of goal-directed arm movements. Experimental Brain Research, 151:524–535. Sarlegna F, Blouin J, Vercher J-L, Bresciani J-P, Bourdin C, Gauthier GM (2004). Online control of the direction of rapid reaching movements. Experimental Brain Research, 157:468–471. Saunders JA, Knill DC (2003). Humans use continuous visual feedback from the hand to control reaching movements. Experimental Brain Research, 152:341–352. Schenk T, Mair B, Zihl J (2004). The use of visual feedback and on-line target information in catching and grasping. Experimental Brain Research, 154:85–96. Sherrington CS (1906). The integrative action of the nervous system. New Haven, CT, Yale University Press. Taub E, Berman AJ (1968). Movement and learning in the absence of sensory feedback. In SJ Freedman (editor): The neurophysiology of spatially oriented behaviour. Homewood, UK, Dorsey Press. Utley A, Sugden D (1998). Interlimb coupling in hemiplegic cerebral palsy during reaching and grasping at speed. Developmental Medicine and Child Neurology, 40:396–404. van Beers RJ, Wolphert DM, Haggard P (2002). When feeling is more important than seeing. Current Biology, 12:834–837. van der Fits IBM, Klip AWJ, van Eykern LA, Hadders-Algra M (1999). Postural adjustments during spontaneous and goal-directed arm movements in the first half year of life. Behavioral Brain Research, 106:75–90. van der Meulen JH, Denier van der Gon JJ, Gielen CC, Gooskens RH, Willemse J (1991a). Visuomotor performance of normal and clumsy children. I. Fast goal-
Reaching and Eye-Hand Coordination • 99 directed arm movements with and without visual feedback. Developmental Medicine and Child Neurology, 33:40–54. van der Meulen JH, Denier van der Gon JJ, Gielen CC, Gooskens RH, Willemse J (1991b). Visuomotor performance of normal and clumsy children. II. Armtracking with and without visual feedback. Developmental Medicine and Child Neurology, 33:118–129. Van Thiel E, Steenbergen B (2001). Shoulder and hand displacement during hitting, reaching, and grasping movements in hemiparetic cerebral palsy. Motor Control, 2:166–182. Volman MJM, Wijnroks A, Vermeer A (2002a). Bimanual circle drawing in children with spastic hemiparesis: effect of coupling modes on the performance of the impaired and the unimpaired arms. Acta Psychologica, 110:339–356. Volman MJM, Wijnroks A, Vermeer A (2002b). Effect of task context on reaching performance in children with spastic hemiparesis. Clinical Rehabilitation, 16:684–692. von Hofsten C (1979). Development of visually directed
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COGNITION AND MOTOR SKILLS Ashwini K. Rao “Perhaps the most incomprehensible thing about the world is that it is comprehensible.” Albert Einstein
CHAPTER OUTLINE CASE SCENARIO MOTOR SKILLS ARE ADAPTIVE What Is the Overall Framework for Understanding Movements? INTRODUCTION TO COGNITIVE CONTRIBUTIONS TO MOTOR SKILLS COGNITIVE PROCESSES IN MOTOR SKILLS Attention Perception Concept Formation (Knowledge) Memory SKILL ACQUISITION (LEARNING) EPILOGUE: RELATIONSHIP BETWEEN COGNITIVE AND MOTOR DEVELOPMENT SUMMARY
Through the course of evolution, the importance of the hand to the organism has increased tremendously. We use our hands to reach out and grasp and manipulate objects, write and draw, make gestures, and create and use tools. Thus our hands are not only used for manipulation skills, but also for communication. The greater importance of hand skills in humans is reflected in an increase in the area of the brain dedicated to hand movement. In addition, cognitive capacity (broadly defined as the collection and organization of information into knowledge) has increased through the course of evolution. This is also reflected in the increase in size of frontal lobe structures in humans when compared with nonhuman primates.
Although the extent of brain structures has increased along with our functional repertoire of hand and cognitive skills, this in no way implies that there is a simple cause-and-effect relationship between brain and behavior. In fact, research on the neural control of movement has shown that although specific areas of the brain are involved in the control of hand movements, the performance of movements in turn influences development of the same neural structures. Thus structure (brain areas involved in hand control) and function (behavioral repertoire of manipulative skills during functional tasks) are intertwined and influence each other through development. Manipulation skills are some of the most complex motor skills and require the coordination of many systems. Within the motor system, manipulative skills require the coordination of many different segments of the body that allow for adapting the hand to grasp different objects and application of precise amounts of force on objects that allow for successful manipulation of objects during functional activity (Flanagan, Haggard, & Wing, 1996). Coordination becomes even more complicated when we consider the cognitive components (e.g., memory, attention, perception) that have to work in concert with the emerging motor skill.
CASE SCENARIO Consider this simple scenario. Jimmy, a 2-year-old typically developing child, is sitting at a table, reaching out to grasp a glass full of water so as to bring it toward his mouth. This simple functional act, one that is carried out by children with seemingly effortless ease, nevertheless is extremely complicated and poses several challenges to a developing system such as Jimmy’s. This
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task highlights the numerous processes that can be categorized as cognitive-perceptual aspects of motor control. Even before beginning the movement of reaching for the glass, Jimmy’s visual processes provide his nervous system with tremendous information about the glass: how far the glass is from him, where the glass is placed on the table with reference to his body, the shape of the glass, how much water is in the glass, the consistency and estimated weight of the glass. The responses to these questions constitute processes called perception and representation. In addition to these perceptual processes, the association of visual input from the glass with symbols about objects provides information that is stored as object knowledge, useful for identification and classification. This information is stored in memory, which can be retrieved at any time. Furthermore, the size and apparent weight of the glass determine whether Jimmy picks up the glass with one or two hands. Such decision making is based on memory of prior interactions with objects. Once Jimmy grasps the glass, his visual and haptic (tactile) processes provide his system with information about the weight of the glass and how the movement of bringing the glass to his mouth displaces the water in the glass. As Jimmy repeats the process of grasping glasses of various sizes, shapes, and weights, and transporting the glass toward his mouth on different occasions, his nervous system internalizes rules about how his movement affects the liquid in the glass through a process of trial and error. This process is called learning and is an essential cognitive skill that enables Jimmy not only to retain the knowledge of how to grasp and lift a given glass, but also generalizes (transfers) this skill to enable successful interactions with various objects.
MOTOR SKILLS ARE ADAPTIVE Motor skills are composed of discrete or sequential movements that are organized in a precise manner to achieve a specific action goal. Sugden and Keogh (1990) described motor skills as “movements that are intentional, goal directed, organized, and adaptive.” This description highlights a few important aspects of motor skills that are particularly important for manipulative skills: 1. The intentional nature of movement indicates a process of planning, which involves cognitive processes 2. The precise nature of movements indicates that movement execution needs to fulfill constraints of the task, and
3. Goal directed indicates that movements, in general, are executed to accomplish a particular action. There are instances in which the goal of the action is a specific set of movements, as in a dance performance. In this chapter, however, we are concerned primarily with manipulative skills that are executed to achieve an action goal (e.g., feeding, object manipulation, writing).
WHAT IS THE OVERALL FRAMEWORK FOR U NDERSTANDING MOVEMENTS? Movements are one of the primary means by which humans interact with the environment and act on the environment. Thus an understanding of movement has to take into consideration an understanding of the nature of the environment in which movements take place. Shumway-Cook and Woollacott (2001) have suggested that movement emerges through an interaction of the performer (including biomechanical constraints of our musculoskeletal system), the task (which can range from body stability to manipulation), and the environment. According to Gentile (2000), the structure of a task determines the demands placed on the performer. Given that different tasks pose different challenges for the performer, it is imperative to begin with an understanding of tasks. Gentile proposed an analysis of tasks that categorized tasks based on their functional role and the environmental context (Gentile, 1972). Based on the functional role, tasks can either specify body orientation (which includes body stability and body mobility) or manipulation of objects. With reference to environmental context, tasks can be categorized as those that are performed in closed environments, which remain stable from trial to trial, or those that are performed in open environments which change from trial to trial. On the basis of this classification, Gentile proposed a taxonomy of tasks that has helped us understand tasks and the challenges they pose, and also as a basis for evaluation and intervention in clinical practice (Gentile, 1992, 2000).
INTRODUCTION TO COGNITIVE CONTRIBUTIONS TO MOTOR SKILLS The importance of cognition in motor skill acquisition and development is well established. However, the reverse also has been proposed: that perceptual motor activity is a mechanism for cognitive development. However, the importance of cognition to motor skills depends on the theoretical orientation that is used.
Cognition and Motor Skills • 103 Some of the major theoretical orientations in the literature are the Piagetian approach (Piaget, 1952), the behaviorism approach of Skinner (1953), the ecological approach of Gibson (1979) and more recently, the information processing approach that has been reformulated within the relatively new discipline of cognitive neuroscience (Gentile, 2000; Thelen, 1995). Each of these approaches is discussed briefly. For the purpose of this chapter, the cognitive neuroscience approach is used. Piaget considered that motor activity was necessary to the development of knowledge about the environment. Knowledge development was believed to be a function of the interaction between neural structures and the environment. According to Piaget, cognitive functions develop through knowledge gained as a result of action, which early in development is based on innate reflexes (Piaget, 1952). Based on this approach Piaget proposed a stage-like developmental process in which new skills are learned based on skills previously learned in development. For Piaget, infant motor activity played a major role in cognitive development. Object manipulation was believed to be critical for the child’s learning about object properties. The manipulation of objects is important as a way of facilitating mental activity, which is believed to be the key for learning object characteristics. Overall, in this approach, cognitive-neural development is thought to play an important role in development of skills, whereas factors outside the performer (i.e., the environment) are not emphasized. This is in stark contrast with the behavioral approach, pioneered by Skinner and his colleagues, which emphasized the role of reinforcement from the environment as a primary driving factor in development (Skinner, 1953). Development, according to this framework, occurs through the responses of the performer and the reinforcement she or he receives through the environment. One approach that differed from these two approaches was proposed by Gibson (1979). In this approach action is not a precursor to perception. Rather, perceptual information is actively sought through coordinated systems of action, some of which are already functioning in this capacity at birth. This approach proposed that most of the information needed for the control of motor skills was contained in the flow of sensory afference (visual or haptic). Development was thought to be a process whereby the performer learns not so much to improve his or her movement skill per se, but to learn to use the information contained in the sensory flow. Although this approach explained some of the behaviors seen during development, it did not highlight the role of neural structures in the developmental process.
The emerging approach in motor development is one that developed out of the information processing theories and current theories in motor control. Much of this approach was influenced by Bernstein, a Russian physiologist, who proposed that movements emerge through the interaction among the performer, the impact of movements made by the performer, and the environment (Bernstein, 1967). Within motor development, the application of this approach was pioneered by Esther Thelen (1995). In this approach, movements are proposed to emerge through the cooperative interaction of many body parts and the environment, rather than from a one-to-one mapping between neural structures and movements. Because movements are slightly different from trial to trial (even when the same muscles are activated), Bernstein proposed that actions were planned at a more abstract level. This is particularly true because it is impossible for the nervous system to program all the force-related contextual interactions ahead of time. Thelen (1995) argued that cognition and motor skills emerge from a dynamic process in which the performer learns the match among herself, her movements, and the environment and how the various component parts are coordinated to produce skillful movement. Thus early in the development of a skill, a high degree of variability is seen in the behavior. Rather than seen as an undesired outcome, variability is seen as functional, and is exploited in the generation of solutions. With development, the macrostructure of the movement (the visible motor output) becomes less variable and more stable, but this stability arises as a result of maintaining variability at a microstructural level, which refers to the forces generated and the patterns of muscular contraction (Manoel Ede & Connolly, 1995). With this framework in mind, we explore the different constituents of cognitive skill and their relationship to motor skills. Although an attempt is made to present the most pertinent and current literature on infants and young children, at some points results from adult studies are presented when little or no evidence is available from the developmental literature.
COGNITIVE PROCESSES IN MOTOR SKILLS In this section, we discuss a few important components of cognition critical to the successful generation of motor skills. Attention, perception, concept formation, memory, and learning are briefly discussed. Although each component is discussed separately for clarity, one should understand that in the development of motor skills, many of these components interact with each
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other and may assume differential importance depending on the demands of the task.
ATTENTION Attention is a fundamental aspect of all human activity. We are able to perceive stimuli and act on them better when we attend to the stimulus of interest and ignore extraneous stimuli. Our sensory systems receive a tremendous amount of information. If we did not have a mechanism to filter unwanted stimuli, we would encounter sensory overload. At any given moment, we are aware of only a few stimuli that are functionally important to the task at hand, and our awareness is limited by our capacity for processing information. Thus functional attention is selective by definition. Attention can be defined by examining its constituent parts of arousal, capacity, and selectivity (Plude, Enns, & Brodeur, 1994). Arousal refers to the momentary level of excitation in the information processing system that helps tune our cognitive systems to optimally receive information. Capacity refers to the actual capacity of our information processing system. It is generally accepted that humans can process a certain amount of information at any given moment. Finally, selectivity refers to the ability of the system to allocate resources so as to focus on certain stimuli and not others. Selective attention is a multidimensional process, involving components of orienting, filtering, searching and expecting (Plude et al., 1994). From an early age, infants show preference for orienting their vision to attend to certain stimuli while ignoring others (Maurer & Lewis, 1991). In fact, neonates spend more time attending to their mothers’ face than the faces of strangers, even when other sensory cues, such as smell and auditory cues, are excluded (Bushnell, Sai, & Mullin, 1989). The orienting response is variable and not developed early in life, presumably because the neural structures that control such behavior (e.g., the superior colliculus) are not fully developed. Nevertheless, the evidence suggests that infants demonstrate beginning capabilities for selective orientation to preferred stimuli. Another aspect of selective attention is that infants show a preference for novel stimuli rather than stimuli that have been present in the environment. Most of us have observed infants paying more attention to new faces in comparison with familiar faces. This phenomenon is known as habituation and refers to the decrease in the amount of visual attention (time spent on a stimulus) devoted to more familiar stimuli (Bertenthal, 1996; Ruff, 1986). Ruff found that the amount of time spent in examining novel stimuli decreases as the infant becomes familiar with an object and suggests that the
time spent on novel stimuli may be influenced by the arousal properties of the object. Although infants have some capability in orienting to stimuli, as shown in the preceding paragraphs, their ability to devote attention resources to actively search for objects of interest does not develop until early school years (Cohen, 1981). Similarly, the skill of paying attention to stimuli that has already been experienced develops during the early school years. This phenomenon, known as priming, refers to the fact that we are able to better attend to stimuli that has been presented before, even if for a short period of time. Priming also explains how certain stimuli are recalled easily because of prior exposure (Plude et al., 1994). To summarize, attention is a fundamental aspect of cognitive skills that is related to perception and memory. When we consciously attend to a sensory stimulus, our perception is matched to information stored in our memory (priming or recognition). Attention is an active process in which certain stimuli in the environment are given preference over others depending on their perceived importance to the demands of the task being performed.
PERCEPTION Perceptual processes constitute an important part of cognitive contributions to motor skills. Perception can be defined as a process of collecting information from the environment based on vision, touch, hearing, and muscle and joint proprioceptors to construct an internal representation of space and the body (Kandel, 2000). Thus our perception is created through an active process of searching for and attending to stimuli based on our sensory organs. All pertinent information is then used in the construction of an internal representation. Historically, perception was thought to emerge from a developmental process as infants and young children developed their repertoire of sensorimotor behaviors (Piaget, 1952). The current view, however, challenges this notion and proposes that different sensory inputs converge into a unified representation that precedes thought and action (Marr, 1982). The emerging framework from the cognitive neurosciences proposes that there may be at least two independent and parallel perceptual processes: one that is used in the recognition of objects and the other used for the guidance of movements (Goodale et al., 1994). Thus visual information about an object in the environment is processed by separate neural pathways and used for different purposes (Bertenthal, 1996; Goodale & Westwood, 2004). The system for the identification of objects, also called the ventral stream, is proposed to project from the visual cortex to the temporal lobe. The system for
Cognition and Motor Skills • 105 action, also called the dorsal stream, is proposed to project from the visual areas to the posterior parietal cortex. Although most of the evidence for this proposal comes from neurophysiological studies from nonhuman primates, neuropsychological studies in humans with focal cortical lesions, and imaging studies in adults (Goodale & Westwood, 2004), some authors have proposed that such a dissociation may be present during development (Johnson, 1990). There are fundamental differences in these two subsystems that support the notion that they operate independently. First, the system for the guidance of movement is proposed to work in a prospective manner because actions are directed toward information present at the time. Von Hofsten has argued that actions occur through dynamic interactions between an organism and the environment that occur in a future-oriented manner (von Hofsten, 1993, 2004). For example, in reaching for objects, infants begin to crudely adjust the orientation of their hand to match the orientation of the object even before grasping the object of interest (von Hofsten & Fazel-Zandy, 1984). Such adjustments are made in an anticipatory (prospective) manner to maximize success at reaching objects. This is in contrast with the system that is used for object identification in which the information is retrieved from a representation that is stored in memory (Goodale et al., 1991, Goodale et al., 1994). Second, the difference between these systems pertains to the manner in which the information is structured in the brain. All sensory information is structured and represented in a format of coordinates called a coordinate system. Although the information used for perception and identification of objects is structured in a coordinate system centered on the environment (or world centered), information that is used for the guidance of movement is structured in body coordinates (Goodale & Westwood, 2004). This is because perception of objects requires that the observer be able to identify object features correctly independent of his or her position vis-à-vis the object. In contrast, sensory information used for guidance of movement is structured in body centered coordinates (Soechting & Flanders, 1992). This is because sensory information used for movement ultimately has to be converted into patterns of muscle activation that will move the arm to the desired object. Because specification of movement parameters ultimately has to match egocentric coordinates of muscle action, it seems likely that such information is stored in body-centered coordinates. Third, these two systems also differ in terms of the nature of conscious processing involved. The system that deals with object perception and identification processes visual information in a conscious manner because the observer is required to actively attend to
the stimulus. In contrast, the system that deals with guidance of movement processes information subconsciously. We are not conscious about processing sensory information when manipulating objects. Perhaps the best evidence for this dissociation comes from studies of patients with brain lesions who are unable to perform conscious processing necessary in identification of objects but nevertheless are able to reach out and grasp them (Goodale et al., 1991). For instance, patients with lesions of the ventral stream (pathways from the primary visual cortex to the temporal lobe structures) are unable to identify objects but are able to reach out and grasp objects with problems. Patients with lesions of the dorsal stream (the posterior parietal cortex) show the opposite deficit: They are able to identify objects but are unable to reach out and grasp them (Goodale & Westwood, 2004). Thus converging evidence from animal studies and human lesion studies suggest that information for perception and action are processed independently. The system involved in perception perhaps develops later as it involves conscious processing of knowledge from memory, skills that develop as a child learns language.
Perceptual-Motor Processes We must perceive in order to move, but we must also move in order to perceive. (Gibson, 1979) This statement, from one of the most influential psychologists in the area of perception, highlights the reciprocal relationship between perception and action. According to Gibson (1979) perceptual systems have adapted to use information pertinent to actions that are readily available in the environment. For instance, perceptual-motor systems use visual information available in the optic array, haptic information from hands as they explore objects, and proprioceptive information available from muscles and joints. Although movements are adapted in response to perceptual processes, the reverse is true as well. Such reciprocity was shown in a study that tested crawling infants and recently walking infants on their locomotion on two different surfaces; a rigid and a pliable surface. Although crawling infants did not differentiate between these two surfaces, recently walking infants changed their mode of locomotion depending on the surface. They crawled on the pliable surface and walked on the rigid one (Gibson et al., 1987). More recently, it was shown that recently walking infants adopt a more stable posture (sitting) as they negotiate a surface with a downward incline, whereas crawling infants did not adapt their posture (Adolph, Eppler, & Gibson, 1993). These studies show that perception (e.g., perceived stability of surface)
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influences action and action in turn influences perception (e.g., newly walking infants differentiating among surfaces). Contrary to the proposals of early models of perceptual-motor development (Piaget, 1952), goaldirected behavior is observed very early in development. Infants as young as 3 weeks old have been observed to reach out and grasp stationary and moving objects (von Hofsten, 1982). Neonates actively control their gaze and look at faces that engage them in a mutual gaze (Farroni et al., 2002), and visually track moving objects within their first month (Bloch & Carchon, 1992). Von Hofsten (1993) argues that behaviors that are explored in the womb (e.g., hand-tomouth behavior) may demonstrate an advantage after birth. The evidence described in this section highlights that infants are capable of goal-directed movements based on visual information available in the environment (e.g., from a moving object). Although this behavior is highly variable from trial to trial, and fragile (it is not observed consistently), the existence of such control provides evidence that our perceptual systems are tuned to act on visual and haptic information from a very early age. According to Thelen (Thelen, 1995; Thelen & Corbetta, 1994), behavior is highly variable when first expressed and is gradually adapted as a result of a dynamic process of selection of the most appropriate coordinative structures that are specific to the contextual demands of the task. The contextual nature of perceptual-motor behavior, in part, is dependent on the fact that motor skills are not simply influenced by perceptual processes but also by biomechanical and physiologic factors. For example, although infants are able to reach for moving targets at the age of 3 weeks, such behavior is contingent on the stability of their head (von Hofsten, 1982). When the head is not stabilized, goal-directed reaching is not observed. In a now classic example of the contextual nature of perceptual-motor behavior, Thelen and colleagues described the case of the “disappearing reflex” (Thelen, 1995; Thelen, Fisher, & Ridley-Johnson, 1984). Infants are known to demonstrate a stepping reflex when held upright with their feet on a supporting surface. Within a few months, this “reflex” pattern of movements is not seen. The traditional explanation for the disappearance of this reflex was that the maturing nervous system inhibited the reflex, a primitive behavior. However, at the same time that the reflex disappears, infants also demonstrate an increase in their body mass. When such infants were held upright partially submerged in water with their feet in contact with a surface, the stepping reflex re-emerged, indicating that the reflex “disappeared” primarily because of increased weight and a biomechanically demanding posture (Thelen et al., 1982; Thelen & Fisher, 1982)
rather than simply because of neuromaturational factors.
CONCEPT FORMATION (KNOWLEDGE) Concept formation refers to a higher-order mental process that acts on information that has been perceived through our sensory organs and encoded and stored in memory. This process includes organization of the information into conceptual categories and the use of such knowledge in reasoning, problem solving, goal selection, and planning. Through the process of categorization, infants and young children begin to form concepts about objects, people, and actions. For instance, early in development, infants learn to categorize faces as familiar and unfamiliar. As discussed in an earlier section, infants are seen to spend more time attending to faces that are familiar, such as the mother (Bushnell et al., 1989). This indicates that infants have already begun to categorize faces according to their perceived familiarity. Concepts (e.g., faces and objects) are units of mental representation that assign certain perceptual features to specific conceptual categories. Early in development, we learn to differentiate between living and nonliving objects, based on our ability to generate selfmotion. This process becomes more complex as we learn to differentiate subcategories within these categories of living and nonliving objects. Knowledge organized into such categories is encoded and stored in long-term memory and retrieved during action. Key elements of concept formation are the processes of grouping and differentiation. Grouping involves the clustering of information into larger units, a process known as “chunking” (Gentile, 2000). Chunking helps the system function more efficiently because the performer has to attend to groups of information rather than each piece of information separately. The benefits of chunking perhaps can be seen best through an example: Consider a child walking through his classroom to his teacher. In performing this task, he encounters numerous toys strewn across the floor, furniture placed all over the room and a few peers running around in the classroom. The process of chunking allows the grouping of all stimuli into stationary and moving objects; this way the child can perceive the movement of his peers as a unit rather than attend to the movement of each child individually. Grouping reduces the attention demands of the task and allows the child to allocate his attention to additional stimuli (furniture) that are important. Differentiation, on the other hand, refers to the process through which performers perceive more detail in an array of stimuli as they become more familiar with it. To use the example cited in the preceding paragraph,
Cognition and Motor Skills • 107 as the child begins to learn to walk, he will likely not perceive the subtle differences in the speed of movement of the moving objects in the environment. With experience, he will learn to distinguish between stimuli related to other children either walking or running. Development of concepts and knowledge is extremely useful for understanding the demands of the task and goal completion. Early in the learning of a task, performers should learn the relationship between movement and the goal of the movement. Failure to understand the goal of the task can lead to goal confusion, which is commonly seen in elderly individuals with memory disorders (Gentile, 2000). Specification of the goal of the task has been shown to be critical in improving the quality of movement (determined by kinematic analysis) in unimpaired adults (Lin, Wu, & Trombly, 1998; Wu et al., 1998) and individuals recovering from a cerebrovascular accident (Wu et al., 1998). Changing the goal of the task influences the movement pattern selected. In a classic study (Marteniuk et al., 1987) demonstrated that unimpaired subjects reached for and grasped a disc differently depending on whether the goal of the task was to place the disc accurately in a container or to throw the disc. Attention to the goal and knowledge of the relationship between movement and its outcome (action) are key components of concept formation pertaining to hand skills. In summary, concept formation is a conscious and active process that categorizes sensory information by associating it with conceptual categories. These categories are stored in long-term memory and retrieved in response to the demands of the task. As stated earlier in the chapter, such information is thought to be processed through ventral neural pathways projecting from the visual cortex to the temporal cortex (Goodale, 1992).
M EMORY Memory is the process by which knowledge is encoded, stored, and retrieved (Milner, Squire, & Kandel, 1998). The neurobiological pathways responsible for memory are dependent on our sensory perceptual and attention processes (discussed in the preceding sections) that allow task-related information to be stored. Most models of memory propose the existence of multiple systems of memory, each devoted to a specific function (Willingham, 1997). Memory can be classified in many different ways: One is to classify it according to the time scale of the operation. Thus we distinguish between short-term (working) and long-term memory systems. Working memory is proposed to be a dedicated system that holds information for short periods of time
so that it can be manipulated during functional tasks. According to Baddeley (2003), working memory is a limited capacity system that supports thought processes by providing an interface among perception, long-term memory, and action. Working memory is proposed to consist of at least three components: a central executive, and two storage loops; the phonological loop and the visuospatial sketch pad. The central executive is proposed to be the attention control system, which regulates the function of the other two subsidiary rehearsal systems. The central executive also serves as a buffer that holds information temporarily. The phonological loop contains a phonological store “which can hold memory traces for a few seconds before they fade, and an articulatory rehearsal process that is analogous to sub-vocal speech” (Baddeley, 2003). The phonological loop has a limited capacity that limits the amount of information that can be held and manipulated at any given time. Finally, the visuospatial sketch pad is also a limited capacity rehearsal loop and mainly deals with spatial information perceived through the visual system (Baddeley, 1998). The function of the visuospatial loop is to hold and manipulate visual spatial representations, as seen in tasks that require mental rotation of images. Most of the evidence supporting the model of working memory comes from studies in unimpaired adults and adults with focal cortical lesions. From a developmental perspective, it seems likely that the visuospatial sketch pad develops before the phonological loop because the phonological loop is dependent on language-based processes. Studies on the development of working memory report age-related differences in the speed with which words can be articulated and differences in attention span (Hitch & Towse, 1995). These age-related differences appear to result from maturational factors (Cowan et al., 1999). The other major classification that pertains to longterm memory is based on how the information is stored and recalled. According to this classification, memory can be either explicit (or declarative) or implicit (procedural). Explicit memory is associated with conscious awareness and the intention to recall information. This form of memory typically is tested with recall or recognition and underlies the memory for objects, people, and events. Studies with infants have revealed that they can retain memory for objects (as tested by retention) across intervals of 1 to 3 months (Bahrick & Pickens, 1995). Based on additional studies, Bahrick and colleagues proposed that recent memories are expressed as a visual preference for novelty, whereas remote memories are expressed as a preference for familiarity (Bahrick, Hernandez-Reif, & Pickens, 1997). However, younger children need greater numbers of prompts to recall memories compared with older children.
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Explicit memories are further divided into memories for facts (semantic memory) and events (episodic memory). Semantic memory is built up by associating a stimulus with specific concepts. Thus a visual image of an elephant associates features of the elephant (e.g., its large size, large ears, tusks, and small tail) with the conceptual category of “elephant.” This information is then further associated with additional knowledge about elephants that allows children to close their eyes and recall an internal representation of an elephant. Semantic memory is thought to be stored in a distributed fashion in the neocortex, including the medial temporal areas that process verbal information and occipital areas that process visual information. Episodic memory, on the other hand, is concerned with the temporal ordering of events. In children, this type of memory is built up by associating events with what happened during such events (Schneider, 2000). Explicit memory is processed in four distinct phases. The first phase is called the encoding phase, during which new information is attended to and processed at first encounter. All pertinent information in the stimulus must be attended to for memory to be stored in long-term memory. A second phase is consolidation, in which the new information is altered from a labile state to a stable state for long-term storage. Consolidation is a time-dependent process, and any event that interferes with this process prevents new and labile information from being converted to long-term memory. The third phase is storage, which refers to the mechanism by which memories are retained over time. Finally, the fourth phase is retrieval, which refers to the process of recall of memories (Kandel, 2000). Implicit memory, in contrast with explicit memory, is concerned with storage and recall of information without conscious awareness (Milner et al., 1998). This kind of memory is also called procedural memory, because it refers to knowledge about “how” a task is performed, rather than “what” a task is. Implicit memory does not depend on conscious processing of information, builds slowly over time through repetition, and is primarily expressed through performance rather than through language (Kandel, 2000). Most of the early evidence of the distinction between implicit and explicit memories came from the study of individuals with focal lesions of the medial temporal lobe. In one patient (HM) most of the medial temporal lobes were removed secondary to seizures. The surgical lesion left HM with a memory deficit of explicit long-term memory, particularly for facts and events that occurred after the surgery and also a deficit of events that occurred immediately before the surgery (retrograde amnesia). Although he had a relatively intact short-term memory, HM was unable to transfer information from short-
term to long-term memory (Milner et al., 1998). Despite his devastating deficit in explicit (declarative) memory, HM could learn new motor skills such as mirror drawing (Milner, Corkin, & Teuber, 1968) or novel patterns of arm movements (Shadmehr, Brandt, & Corkin, 1998) comparable to age-matched unimpaired subjects. Thus patients with temporal lobe lesions are able to learn tasks that do not require conscious awareness and tasks that are procedural. These studies have helped us understand that explicit and implicit memories are independent systems, controlled by different areas in the cortex (Milner et al., 1998). For the developing child, it has been shown that older children demonstrate an advantage for explicit memories, whereas there is no specific age-related difference in the formation of implicit memories. This difference in the development of the two memory systems may result from the fact that sensory and perceptual systems are developed early in life (as discussed in the preceding section), whereas concept formation (which is necessary for development of explicit memories) continues to develop until the school years (Bertenthal, 1996; Schneider, 2000).
SKILL ACQUISITION (LEARNING) Learning is the process by which we acquire knowledge about the world and ourselves. Skill can be defined as consistently attaining an action goal with some economy of effort (Gentile, 2000). Learning of motor skills concerns a set of processes associated with practice or experience, which leads to a relatively permanent change in the ability of the performer to produce movements (Shumway-Cook & Woollacott, 2001). Box 6-1 highlights a few important concepts. Learning is thought to progress in stages. Although different models of learning have been proposed, most models agree that different processes operate during the early and late stages of learning. For the purpose of this chapter, we discuss the two-stage model proposed by Gentile (1992, 1998, 2000). According to this model, in the early stages of learning, the performer acquires the general concept of the demands of the task and the movements that are necessary to successfully achieve the goal. Part of this process is to understand and attend to important features of the action goal: This enables the performer to focus on the regulatory features in the environment and ignore the nonregulatory features. According to Gentile (2000) the action goal concerns the function of the task (whether the task requires manipulation or requires body orientation or both) and the nature of
Cognition and Motor Skills • 109 BOX 6-1
Descriptions of Learning
1. Learning is a process whereby a child acquires the capability for skilled action. 2. Learning results from practice or experience, rather than being simply a function of neuromaturation. Perhaps this concept is best highlighted by the fact that infants practice tasks such as reaching (von Hofsten & Fazel-Zandy, 1984) and locomotion (Adolph, 1997) several hundred times in a day over a period of months before they become skilled. This extended practice is the basis for improvement of skill. 3. Learning is a process that cannot be observed directly and typically is inferred from changes in behavior. As discussed in the preceding sections, much of the evidence on motor development has come from detailed longitudinal observational studies in infants and young children (Adolph, 1997; Thelen, 1995; von Hofsten & Fazel-Zandy, 1984). 4. Learning produces changes that are relatively
the environment in which the action is taking place (whether the environment is stationary or in motion). Focus on the regulatory features necessitates selective attention to pertinent stimuli. During this process, the performer’s system learns to differentiate the environment (perceive greater detail in the sensory array) and grouping of similar stimuli into chunks, a process described earlier. During this phase, the child pays attention to the overall structure (shape or configuration) of the movement. Thus in reaching for an object, a child is aware of the orientation of her hand as it attempts to approximate the orientation of the object for successful grasp. Gentile (1992) terms this the topology or shape structure of the movement. Although the performer is aware of the topology, she or he is not aware of the internal processes of parameter specification that specify the timing of the movement components, the forces to be imparted to the limbs, and so on. During this early stage, based on the results of the movement, the child receives feedback on the outcome of the movement. This knowledge is then encoded and stored in memory and helps the child learn the association between movement patterns and their outcome. This process enables children to repeat successful movements and leads to the formation and refinement of internal models (or representations) of the task. Studies of infants learning to perform goal directed reaching have demonstrated evidence for this notion. Recording of the movement patterns of infants have shown that early in learning, arm reaching movements are extremely variable and the goal of reaching for and grasping an object is not achieved consistently. How-
permanent. This indicates that information acquired through learning is stored in long-term memory, which typically is retained over long periods of time. 5. Learning is task specific. A pattern of movement that produces successful goal-directed interactions may not be sufficient if there are changes in the environment or in the morphology of the performer, as happens continuously through development. Thus skill attained under certain conditions can be generalized only to other skills that share features with the original skill learned. For instance, once a child learns to reach for one stationary object, she or he can adapt this skill and generalize it to successfully reach for stationary objects of different shapes and sizes; however, this skill of reaching for stationary objects does not necessarily generalize to reaching for moving objects because such a task poses different challenges to the system and requires novel solutions.
ever, within a relatively short period of time, movements converge to a consistent topology enabling the child to achieve the goal more consistently (Konczak et al., 1995; von Hofsten et al., 1984). With refinement of the internal model, the abstract representation of the movement and outcome becomes independent of the actual environmental and biomechanical constraints. For instance, in learning the task of writing, a child acquires an internal model of the task. In this case the movements of the hand (and the forces applied) that produce the form (or topology) of a letter. Once this model is learned, the child can perform this task not only with the dominant hand, but with the nondominant hand as well (although not as efficiently because the nondominant hand is not as skilled). The fact that we can produce the same action using different effectors highlights the importance of an internal model (abstraction) of the task that is independent of the effectors. Skill is refined during the later stages of learning. Performance improves but at a much slower rate than in the early stages of learning. In this phase improvements occur in the efficiency of the movement: The child is better able to predict the consequences of her movement and better able to produce consistent movements from one trial to the next. According to Gentile (1998) this phase is characterized by changes that the performer is not aware of. The changes pertain to the parameter specification, and include improvements in the timing of force generation of the segments involved in the movement and the timing and amplitude of muscle contractions that ultimately produce the
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movements. In addition, movement sequences are more efficiently blended together temporally so that each sequence is not discernible from other sequences of movement. The evidence from recording of intersegmental forces and patterns of muscle activation demonstrates that improvements at this level of the system continues over a much longer period of time (Konczak, Borutta, & Dichgans, 1997). Although the topology of reaching movement improves within the first few months, improvements in the coordination of forces continue until at least the third year. This underscores the fact that consistency in the external features of movements (e.g., topology) are contingent on internal features (e.g., coordination of forces and muscle patterns) that remain variable over a much longer period of time (Manoel Ede & Connolly, 1995). It can be argued that the variability in the coordination of forces allows the system flexibility and generalizability. In summary, learning is thought to progress through two interdependent and parallel processes. The early phase is characterized by establishment of a mapping between the performer and the environment that, with practice, quickly improves the overall shape structure of the movement. The processing of information during this phase is explicit in nature and leads to the formation of an internal model of the task (Gentile, 1998). Later in learning, movements are refined at a micro level that is not observable in the behavior. The processing of this information progresses without conscious awareness on the part of the performer (i.e., implicitly). Because the improvements at this stage concern coordination of the details of intersegmental forces, the later stage of learning is extended over a longer period of time (Gentile, 2000).
EPILOGUE: RELATIONSHIP BETWEEN COGNITIVE AND MOTOR DEVELOPMENT Historically, motor development and cognitive development have been studied separately and viewed as somewhat independent of each other. It was also a widely held belief that cognitive development occurred over a longer period of time compared with motor development. It is now apparent that motor skills, particularly complex skills such as bimanual control and some visuomotor skills, continue to develop until adolescence. A recent development in the understanding of the relationship between cognitive and motor development proposes that they are in fact highly interrelated. This relationship is primarily
ascribed to the relationship between the prefrontal cortex (which was thought to control cognitive skills) and the cerebellum (which was thought to be involved in movement), both of which are proposed to be involved in cognitive and motor skills (Diamond, 2000). Evidence for this proposal comes from imaging studies during performance of motor or cognitive skills and studies with patients with cortical and cerebellar lesions. In terms of learning of motor skills, it has been shown that both the prefrontal cortex and cerebellum are activated: The activation shifts from the prefrontal cortex to the cerebellum as the task is learned (Shadmehr & Holcomb, 1997). Coactivation of the prefrontal cortex and cerebellum also has been seen in working memory tasks (Desmond, Gabrieli, & Glover, 1998; Smith & Jonides, 1997). According to Diamond (2000), both the cerebellum and prefrontal cortex are active under certain conditions; when the task is more difficult, novel as opposed to familiar, unpredictable as opposed to stable, and requires a quick response (p. 45). Patients with lesions to the cerebellum demonstrate deficits in a variety of cognitive tasks such as working memory tasks administered through bedside neuropsychological tests, set shifting tasks, and visuospatial memory tasks (Schmahmann & Sherman 1998). These deficits are presumably seen because of the interconnections between the prefrontal cortex and the neocerebellum (Ghez & Thach, 2000). Developmental evidence in support of this theory has come from studies that have examined motor problems in children with cognitive problems. Attention deficit hyperactive disorder (ADHD) is a syndrome in which children demonstrate cognitive deficits, including a short attention span. It is interesting to note that along with deficits in cognition, many children with ADHD demonstrate motor deficits as well (Kadesjo & Gillberg, 1998). This may be related to a decreased size of the cerebellum in children with ADHD compared with unimpaired children (Castellanos, 1997). Similar motor deficits are also reported in children with dyslexia. In one study, it was reported that children with dyslexia have problems with motor tasks that require control of the timing of movements, such as tapping a rhythm (Geuze & Kalverboer, 1994). Because timing of movements is a function attributed to the cerebellum (Ghez & Thach, 2000; Keele & Ivry, 1990), and given the connections between the cerebellum and prefrontal cortex, it is not surprising that children with dyslexia demonstrate motor deficits. Children with autism also show deficits in motor tasks, particularly in the execution of goal-directed movements (Hughes, 1996). Although the motor deficit in all these disorders is not the most significant, the existence of these motor disorders highlights the close relationship between cognitive and motor skills.
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SUMMARY In this chapter we have described motor skills as goal oriented and made up of movements that are organized to solve the spatial and temporal challenges presented by specific tasks. In addition to the control processes underlying motor control, we have described many components of cognitive skills that are important for the development and execution of motor skills. Cognitive development and motor development are closely related and have a reciprocal relationship. Hand function is critical in supporting cognitive development because hand movements allow for interactions with objects that in turn support the development of knowledge about objects. Tool use with the hands almost always requires cognitive skill to comprehend the means–end relationship of movement to goal or outcome. In contrast with hand skills, gross motor skills seem to require little cognitive development for their emergence. This chapter has covered a number of topics related to the literature on the relationship between motor skills and cognition. The past few years have seen a fundamental shift in the way in which we understand the relationship of cognitive and motor skills and our understanding of development in general. The emerging paradigm proposes that movement skills are developed not only as a function of neuromaturation, but also through the interaction of emergent movement and cognitive skills with the environment. This new paradigm “emphasizes the multicausal, fluid, contextual and selforganizing nature of developmental change, the unity of perception, action and cognition, and the role of exploration and selection in the emergence of new behavior” (Thelen, 1995).
For therapists interested in learning better ways to teach children to learn or relearn cognitive and motor skills, the new paradigm offers novel ways to assess and plan interventions. For instance, different interventions may be necessary to facilitate implicit versus explicit learning. Although therapists can use conscious processes to facilitate explicit learning, the only way to enhance implicit learning is to carefully structure the environment and select tasks for optimal practice, and provide timely feedback and structure ample opportunities for prolonged practice (Gentile, 1998). Thus therapists not only have to keep the child in mind during the assessment and intervention, but the environment in which the skills are performed as well. As we develop greater knowledge of the differential impact of cognitive disability (e.g., attention, perceptual, memory, conceptual) on the acquisition of motor skills,
the challenge ahead will be to develop creative therapeutic solutions that enhance skill acquisition.
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Chapter
7
HAND SKILL DEVELOPMENT IN THE CONTEXT OF INFANTS’ PLAY: BIRTH TO 2 YEARS Jane Case-Smith
CHAPTER OUTLINE DEVELOPMENTAL THEORIES AND CONCEPTS A Neuromaturation Model Individual Patterns in Hand Skill Development Hand Skills Emerge Through the Interaction of Systems Perception as a Primary Influence on Hand Skill Development Development of Hand Skills for Functional Outcomes CONTEXTS FOR HAND SKILL DEVELOPMENT SYSTEMS THAT CONTRIBUTE TO THE DEVELOPMENT OF HAND SKILLS
The development of prehension and bimanual coordination is essential to an infant’s ability to play and explore. As hand skills mature, the infant becomes increasingly competent in exploring and playing with objects. The young infant’s rudimentary grasp and release patterns become precise patterns during the first years of life. The purpose of this chapter is to describe the infant’s development of grasp, release, and bimanual skills in the context of exploratory and functional play. The first section describes developmental theories and concepts helpful to understanding the development of hand skills. The second and third sections describe how contexts, posture, and sensory function influence hand skill development The fourth section describes the play activities and specific hand skills that characterize the sequential stages of infant development, birth to 2 years.
Posture Sensory Systems DEVELOPMENT OF HAND SKILLS IN THE CONTEXT OF INFANT PLAY ACTIVITIES
DEVELOPMENTAL THEORIES AND CONCEPTS
Play Activities: Birth to 12 Months Prehension: Birth to 12 Months Object Release: Birth to 12 Months Bimanual Skills: Birth to 12 Months Play Activities: 12 to 24 Months Prehension: 12 to 24 Months Object Release: 12 to 24 Months Bimanual Skills: 12 to 24 Months SUMMARY
A N EUROMATURATION MODEL Early theories of motor development (Gesell, 1928; Halverson, 1931, 1937; Shirley, 1931) emphasized the importance of central nervous system control over motor performance. Gesell documented an orderly sequence of motor development, stage by stage, that could be observed in every typically developing child. The theory that maturation of skill and behavior resulted from the maturation of the central nervous system dominated understanding of motor development in the
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1930s and 1940s. Based on neuronal maturation, grasp and manipulation patterns develop in an orderly and relatively invariant sequence. The sequence of reaching and grasping patterns identified in the 1930s by Gesell and Halverson continues to be referenced in developmental motor tests in use today (Bayley Scales of Infant Development) (Bayley, 1993). The neuromaturation theory—that motor development reflects central nervous system maturation— emphasizes that early movements are involuntary reflexes under the influence of subcortical brainstem structures (Andre-Thomas, 1964; Gilfoyle, Grady, & Moore, 1990; McGraw, 1943). Neonates’ reflexive behaviors are automatic reactions to sensory stimulation that result in neonates experiencing arm and hand movements over which they later gain control. Reflexes provide young infants with survival capabilities (e.g., sucking and rooting) and protective responses (e.g., avoiding response). Reflexes allow infants to experience a complete range of movement and tactile proprioceptive input. Reflexes and reactions are modified through interactions with the environment as infants assimilate the sensory feedback from reflexive movements (Gilfoyle et al., 1990). In the first 6 months they become integrated into acquired or voluntary behaviors. McGraw (1943) describes a typical progression of maturation: (a) dominant reflexive responses, (b) inhibition of reflexes, (c) transitional behaviors, and (d) voluntary motor pattern and skill. This typical sequence varies in the timing of onset and completion of each phase but appears to be remarkably invariant in the ordering of developmental motor patterns. When cortical control begins to dominate over subcortical control of hand movement, voluntary grasp emerges. Transitional behaviors mark the period when reflexes are inhibited and voluntary controlled movements begin to develop (Twitchell, 1970). By 4 months the infant grasps a visually located object. A series of studies were completed from 1925 to 1940 to examine the neuromaturation model. These descriptive studies documented the unfolding of grasping patterns in the first year of life (Castner, 1932; Halverson, 1931, 1932, 1937; Jones, 1926). Each researcher investigated specific aspects of prehension development. Jones (1926) was interested in when infants begin to use their thumbs, recognizing the importance of thumb movement to effective prehension. He found thumb opposition to be present in all infants by 9 months. Halverson examined visual control of prehension, approach or reach, and grasping patterns. He documented the emergence of visual attention and visually guided grasp. Halverson reported active thumb movement by 7 months and the beginning of fingertip grasp by 9 months. Castner (1932) was primarily interested in precision grasp of small objects (i.e., a
pellet). His study documented whole hand closure at 5 months, palmar grasp at 8 months, scissors grasp at 9 months, and pincer grasp at 12 months.
I NDIVIDUAL PATTERNS OF HAND SKILL DEVELOPMENT The design of these early studies of hand skill development was cross-sectional; and therefore identified what patterns infants demonstrate at specific ages, but not how infants develop these skills. The purpose of the first developmental studies was to document typical development, without realizing that infants’ individual differences might be more interesting and of equal importance to examine. To learn how infants develop and how developmental patterns differ among individual infants requires longitudinal designs in which performance patterns are observed over time. In assuming a hierarchy of central nervous maturation, the results in an invariant sequence of motor skills development and neuromaturational theory limited the thinking about how a child learns to act on the environment. Current research models (Gibson & Walker, 1984; Smith & Thelen, 2003; Thelen et al., 1993) reveal that infants follow a general sequence of motor milestones, but how they achieve skills is quite individual and infants’ developmental trajectories follow individual pathways. Beginning with Piaget (1952), researchers have demonstrated that children acquire skills through an interaction of their experience and their innate abilities. The influence of the environment on learning and development has become an emphasis of child development research. Behavior patterns are assumed to emerge from an organism– environment coaction (Gottlieb, 1992). This line of reasoning brought new understanding as to how coordinated movements develop, emphasizing the importance of sensory experience and feedback through the hand’s surfaces (Bushnell & Boudreau, 1993; Newell & MacDonald, 1997; Rochat, 1987; Ruff, 1984). For example, the first grasping patterns of neonates are driven by sensory input to the palmar surface. Throughout the first year infants’ actions directly relate to sensory experiences, and movements are adapted based on sensory feedback. Grasp and hold patterns, which are first associated with proprioceptivetactile input, become grasp and manipulate patterns guided by tactile, proprioceptive, and visual input (Bushnell, 1985; McCall, 1974).
HAND SKILLS E MERGE THROUGH THE I NTERACTION OF SYSTEMS Recent research of hand skill development (e.g., Bushnell & Boudreau, 1991; Newell & MacDonald,
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 119 1997; Thelen et al., 1993) has explored how infants’ actions and performance emerge from the interaction of many systems, both internal and external to the child. Factors that influence hand skills include the infant’s size, growth, biomechanical attributes, neurological maturation, perceptual abilities, sensation, and cognition (Gordon & Forssberg, 1997; Manoel & Connolly, 1998; Thelen, 1995; Thelen, Kelso, & Fogel, 1987). Within individual infants, these factors vary with time, activity, and environmental conditions. An infant’s actions during the performance of a task, then, are the results of the subsystems (e.g., motor, sensory, perceptual, skeletal, psychologic) interacting with each other and the environment. These individual systems are interdependent and work together, such that strengths in one system (e.g., visual) can support limitations in another (e.g., kinesthetic). Which systems are recruited for the tasks varies according to the novelty of the activity and the degree to which the task has become automatic. For example, reaching to pick up a cup initially is guided by the visual system, but after it is practiced and learned, reaching is guided primarily by the kinesthetic system, with some direction by the visual system. In contrast, grasping appears to initially involve primarily somatosensory input, but later also is guided by vision. Early grasping and manipulation patterns that are guided by visual and somatosensory input (e.g., play with a rattle) are later guided by cognition and memory (e.g., handwriting). The infant’s sensory–motor–biomechanical systems self organize in a coordinated way to achieve the infant’s goal. For example, when an infant reaches for the toy, grasps it, brings it to midline in hand-to-hand play, and then to the mouth, his attention is not on planning each of these actions. Instead, the infant is focused on assimilating the toy’s actions and perceptual features, organizing his or her movement around that goal. Therefore developmental outcomes reflect both an infant’s self organization and the opportunities in the environment.
Gibson (1988) defines early action as both exploratory (seeking information) and consequential (causing a consequence). The infant’s actions are based on affordances of the environment. Affordance defines the fit between the child and her environment (Gibson, 1979, Gibson, 1988). The environment and objects in it offer infants opportunities to explore and act. The infant’s performance is based on not only what the environment affords, but also her perceptual capability to recognize those affordances. For example, most infant toys provide opportunities for manipulation because they have movable parts, rounded surfaces, and easily fit into an infant’s hand. Individual finger movements, thumb opposition, hand-to-hand transfer, and eye–hand coordination are facilitated by the infant’s perception of the physical characteristics of the toy and his desire to explore those perceptual qualities. CaseSmith, Bigsby, and Clutter (1998) found that toys with movable parts afford higher-level skills than a cube or pellet. The movable parts provide a variety of surfaces for the infant to explore. The toy’s reciprocal action gives feedback to finger movements and sustains the infant’s attention. The perceptual-motor experience of a toy with movable parts is much more interesting than that of a cube (Figure 7-1). The first actions of the infant directly relate to his interest in acquiring perceptual and sensory information (infants first explore objects with their eyes and then hands). Through object manipulation, infants develop haptic perception (i.e., an understanding of objects’ shape, texture, and mass). Specific motor skills are necessary to develop haptic perception. Researchers (e.g., Bushnell & Boudreau, 1993; Lederman &
PERCEPTION AS A PRIMARY I NFLUENCE ON HAND SKILL DEVELOPMENT A first influence on the young infant’s action and movement is sensation. Through vision and touch the infant is motivated to explore his environment and objects within the environment. The infant’s perception of his environment informs action and then his action provides feedback about performance. Initially the infant’s goal is to explore the sensory attributes of objects (e.g., learn their shape, texture, and consistency) (Bushnell & Boudreau, 1993). Soon the infant also learns that his actions cause environmental consequences (e.g., shaking a toy makes a noise).
Figure 7-1 Movements are guided by object affordances. Toys with movable parts elicit a variety of grasping patterns.
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Klatzky, 1987) have demonstrated that young infants develop the hand skills that are necessary to explore an object’s sensory qualities. For example, infants’ first hand skills enable them to squeeze soft objects, run their fingers back and forth over textured objects, rotate, turn, and transfer objects with interesting shapes. Bushnell and Boudreau (1993) noted that infants learn to identify an object’s sensory qualities (e.g., texture, consistency, contour) only when they develop the motor skills to explore each different sensory quality. Therefore an infant does not accurately discriminate texture until she can explore texture by moving her fingers back and forth. She also cannot discriminate hardness until 6 months when she can tighten and lessen her grip while holding an object (Bushnell & Boudreau, 1991). Because configurable shape requires that two hands are involved in exploring the object’s surfaces, infants typically cannot accurately perceive shape until 12 months.
DEVELOPMENT OF HAND SKILLS FOR FUNCTIONAL OUTCOMES Once infants learn to discern the perceptual qualities of objects, they become interested in mastering objects for functional purposes. Through their exploration of objects and the environment, infants realize that they have an effect on the environment and their actions can produce functional outcomes. The outcomes that motivate an infant may be social (e.g., mother’s smile) or physical (e.g., a toy moves, makes a sound, falls over). Functional tasks and outcomes begin to organize the infant’s action (Gibson, 1988). Their actions are intentional and goal driven (Manoel & Connolly, 1998). With this interest in functional outcomes, the infant first attempts to use tools and relate objects to each other (Lockman, 2000). By the end of the first year, infants handle and manipulate objects according to their functional purpose, and the goal of accomplishing a task guides the interaction (Connolly & Dalgleish, 1989). One-year-old infants begin to use a spoon and a cup to self feed. Infants at 14 months can relate one object to another and use simple tools to achieve a goal. By 2 years they learn to hold a comb, a brush, and a marker and crudely apply them in appropriate tasks (Lockman, 2000; McCarty, Clifton, & Collard, 2001).
How Are Functional Hand Skills Learned? Infants generally go through three stages of learning to acquire a new skill (Box 7-1) (Gibson, 1988; Manoel & Connolly, 1998). The first stage involves exploratory activity. As noted in the previous section, the first year of life is primarily a period of sensory motor exploration. Through exploration, an infant learns about
BOX 7-1
Three Stages of Learning to Acquire a New Skill
1. Exploratory activity Learn about objects and tasks A variety of patterns and approaches tried Lower levels of skills used Focus on perceptual learning about the tasks to gain information 2. Perceptual learning and feedback acquired from previous tasks performed Actions initially tried and ineffective are discarded Continue to gain perceptual knowledge about the task Performance is variable, demonstrating higher and lower levels of skill 3. Discovery of the “optimal solution” by selecting the action pattern that will best achieve the goal Pattern selected is comfortable, efficient, and indicates increased self-organization Demonstrates flexible consistency in performance Tends to use a stable pattern for a task (e.g., stack blocks), but can easily adapt the pattern according to task’s requirement (e.g., with larger blocks, heavier blocks) High adaptability characterizes well-learned tasks Mature movement patterns are characterized by adaptable stability Synergist movements (muscles and joints working together) are softly assembled around the goal of the task Specific movement patterns are observed (e.g., a tripod grasp) Generalizes movement patterns to other tasks when well learned for one task
objects and tasks. Most skill acquisition begins with exploration, when a variety of patterns and approaches are tried. New challenges tend to elicit lower levels of skills because these more basic skills can be accessed easily and require less energy and effort than higherlevel skills (Gilfoyle et al., 1990). By using lower-level skills to explore a new task, the child can focus on perceptual learning about the tasks to gain information that will allow mastery with experience. In the second phase of learning a task, the infant uses the perceptual learning and feedback he acquired from attempting to perform the task. Actions that were initially tried and were ineffective are discarded. During this phase, the infant continues to gain perceptual knowledge about the task. Learning potential is high when the task is perceptually interesting and the skill demands are within the capability of the infant. At this transitional phase, the infant’s performance is variable in that he demonstrates higher and lower levels of skill. For example, Connolly and Dalgleish (1989) found considerable variability when infants first attempted to
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 121 use a spoon. McCarty, Clifton and Collard (1999) noted that the transitional stage for spoon feeding is between 14 and 19 months with an “optimal solution” emerging by 19 months. In the third phase of learning, an infant discovers the “optimal solution” by selecting the action pattern that will best achieve the goal. The pattern selected is comfortable and efficient and indicates increased selforganization. During this last stage of learning, the child demonstrates flexible consistency in performance. The infant tends to use a stable pattern for a task (e.g., stack blocks), but can easily adapt the pattern according to the task’s requirement (e.g., with larger blocks, heavier blocks). High adaptability characterizes a welllearned task and mature movement patterns are characterized by adaptable stability (Gordon & Forssberg, 1997; Thelen, 1995; Thelen et al., 1987). Synergistic movements (muscles and joints working together) are softly assembled around the goal of the task, allowing the infant to adapt the pattern he has learned when task variables change. Specific movement patterns are observed in most children, such as a tripod grasp; once a tripod grasp is well learned, it is easily adapted to pens and pencils of different sizes and weights. When movement patterns are well learned for one task and are performed with flexible adaptability, the infant also generalizes them to other tasks. McCarty and coworkers (2001) demonstrated that infants who learned to hold a spoon with a radial grasp consistently generalized this pattern to other tools and tasks with self-directed goals. By 14 months, the infants consistently used a radial grasp on tools that were selfdirected (e.g., a hairbrush), recognizing it as the most efficient grasp for using the tool. A century of research on infant motor development has provided a detailed description of the sequence of hand skills development and a conceptual understanding of how infants develop hand skills. Knowledge about the sequence allows therapists to identify infants who may benefit from intervention and to establish goals that reflect the next skill expected to emerge. The theories that explain how infants develop hand skills form the basis for intervention and educational approaches. One recurring theme in human development research, the relationship between skill development and environmental context, is discussed in the following section.
CONTEXTS FOR HAND SKILL DEVELOPMENT A child’s development is nested in his culture, family, and community; these contexts determine his genetic
makeup and after birth provide his learning environment. Children develop skills through participation in their family’s and community’s cultural practices. Cultural practices are the routine activities common to a community or people and reflect how they play, recreate, and interact in social occasions. The infant’s cultural, social, and physical contexts expand greatly through the first 2 years of life. The widening context affords the infant an increasing variety of experiences, challenges, and opportunities. In most cultures, the first 6 months of life are characterized by closeness to the caregiver. Often children are held and when they are positioned for play, they are immobile for all practical purposes. The infant is quite dependent at this point in life, not only to have his basic needs met, but to bring play objects within reach. In cultures with high interdependence and strong appreciation of extended family, the infant may be continually held by a variety of family caregivers beyond the parents. Hand skills may be practiced on the caregiver’s lap by reaching for and grasping hair, jewelry, or clothing items. First reach and grasp may be practiced on the mother’s breast. A family’s culture background influences the objects made available to the infant. In some cultures, toys are not valued or not available; as a result, young infants do not experience these learning objects. The contexts for play expand for infants after they gain mobility (e.g., around 8 months). Because the infant now can move to play objects, her sense of autonomy increases and she has increasing choice about play with objects. Once the infant is mobile, she is unlikely to spend play time on her parents’ lap and is more likely to play on the floor or in a seating device with the caregiver nearby. Being able to move to a location or object affords the infant greater variety of play objects, enables the infant to develop selfdeterminism, and expands the infant’s perception of form, space, direction, and depth. Cultural traditions influence how much the infant is held, the space afforded to him or her for exploration, and the complexity of the environment available. Infants of families with low economic status may not have appropriate spaces to explore and may be restricted for safety reasons. Families of cultures that value infants’ exploration and play may have more toys and activities available. The effect of poverty on motor skills development is equivocal. Peterson and Albers (2001) found that poverty had a small negative effect on motor development in girls. In contrast, boys whose families had lower income demonstrated higher motor skills than boys from more affluent families. Using a large sample of different ethnic and economic groups, Bradley and co-workers (2001) found that poverty per se did not have a negative effect on infants’ motor develop-
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ment; however, variables sometimes related to ethnicity and economic status (i.e., availability of learning materials and degree of parental responsiveness) did relate to motor development. A number of studies have found differences in hand skill development when children from different cultures are compared. In a study that examined motor performance in Chinese and American children, American children demonstrated higher scores in most gross motor skills and Chinese children were higher in fine motor skills (Chow, Henderson, & Barnett, 2001). The authors suggest that Chinese children may not have the same amount of space available for play and exploration and Chinese parents also may not value gross motor skill development as much as fine motor skill because early proficiency with chopsticks and writing implements is expected. Yim, Cho, and Lee (2003) found that hand strength of children in Korea was lower than in children from America and other Western countries. Although these studies of Chinese and Korean children examined older children (preschool and elementary ages), the results have implications for infants because hand skill and strength develop incrementally from infancy. Differences in caregiving practices across cultures appear to affect infant skill development. When evaluated using the Bayley Scales of Infant Development, 3- to 5-month old Brazilian infants were less skilled in grasping and sitting than American infants (Santos, Gabbard, & Goncalves, 2001). Santos and co-workers attributed these differences to the tradition that Brazilian mothers hold their infants almost constantly for the first 6 months. Because the infants are totally supported for an extended period, their delay in hand skill development may relate to delay in postural stability development. These studies illustrate differences that have been observed in different ethnic groups; however, these differences have not been systematically studied in ethnic groups that live in America, limiting generalizability to children of different cultures who live in the United States.
SYSTEMS THAT CONTRIBUTE TO THE DEVELOPMENT OF HAND SKILLS Extensive research has demonstrated the importance of posture and sensory function (i.e., visual, tactual, proprioceptive) to the development of hand skills (Bertenthal & von Hofsten, 1998; Thelen & Spencer, 1998; von Hofsten, 1986). The reciprocal influence of sensory function was discussed in a previous section.
This section presents a developmental perspective of the influence of posture and sensory functions.
POSTURE The first stable posture of the infant is lying on his back. Laying supine offers optimal stability; the infant must reach against gravity, which constrains reach with grasp. Because posture is unstable in the first months after birth, the 2-month-old infant primarily demonstrates asymmetric posturing, reinforced by the influence of the asymmetric tonic neck reflex (Gesell et al., 1940). This asymmetric posture limits his or her visual field and reinforces visual inspection of the hands (Bower, 1974). To reach and grasp objects, infants must maintain stable vision of the target as they lift their arms. Thelen and Spencer (1998) found that head control is critical to successful reaching. In their study reaching did not emerge in any of the infant participants until several weeks after good head control emerged. By 3 months, the infant has an emerging sense of midline, and when supine brings the head to midline and the hands toward midline. Symmetric weight bearing in prone and increasing head control contribute to establishing a sense of midline. Neck and shoulder stability develops as a prerequisite for control of reach and hand movements in space. Symmetry is the predominant characteristic of the infant’s posture between 4 and 6 months. Head and hands come to midline, enabling a hands-together posture and visual inspection of both hands. As a result, the infant spends much of the time in hand-to-hand play, first on the chest and then in space at the midline. Head and trunk control and postural stability change dramatically during this quartile. Thus the infant gains important axial support for reach and use of hands in space. Stability through the neck and shoulders helps the infant gain control of the arms; therefore in supported positions he or she can hold her hands in space while grasping an object. The movements of neck, trunk, and arms appear to be coordinated early in life. Van der Fits and Hadders-Algra (1998) found that complex postural adjustments accompany the infant’s reach by 4 months, when successful reaching emerges. Therefore as reach and grasp emerge and later mature, postural stability provides a base for these movements. By 6 months, the infant demonstrates increased postural control in the prone position, pushing onto extended hands and shifting weight side to side. When on elbows, the infant is able to lift one arm entirely from the weight-bearing surface for reach to an object. This complete lateral weight shift provides proprioceptive input through the hands across the palmar surface. It also results in asymmetric sensory experiences. Prone
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Figure 7-2
Prone position strengthens arms and hands.
Figure 7-4
Figure 7-3
Most 7-month-old infants sit independently.
positions help the infant strengthen arm and hand musculature and provide tactile proprioceptive information that appears important to the hand’s perceptual development (Boehme, 1988) (Figure 7-2). Although the increased postural control of the 6-month-old child supports symmetric movements of the hands in space, it does not appear adequate for skilled asymmetric or unilateral movements. In the following months, when trunk stability is sufficient for independent sitting, the infant develops an increased repertoire of arm and hand movements that includes both symmetric and asymmetric patterns. Gains in postural control allow the 7-month-old child to sit independently (Figure 7-3). In the next several months sitting becomes a favorite play position because the hands are free to hold objects, and the infant can control weight shift forward or to the sides to obtain objects (Figure 7-4).
Hands are freed to hold objects.
Increased axial control seems to support the use of one-hand reach and bimanual fingering (exploration) of an object held at midline. Trunk rotation has developed in fully supported positions (i.e., rolling from supine to prone and prone to supine) and begins to develop in sitting positions. Related to these skills, the infant demonstrates crossing the midline and begins to use the hand in crossed lateral space. In a review of the research literature, Bertenthal and von Hofsten (1998) reported that reaching skills significantly improve between 6 and 7 months of age. At this age, infants become highly accurate in reaching for a moving target, a task that requires rapid adjustments of arm movement and the postural stability to allow for those adjustments. Infants at 7 and 8 months also assume the quadruped position and begin to creep. The on-handsand-knees position results in frequent weight bearing on the hands. This position tends to be dynamic and mobile, thereby providing tactile and proprioceptive input across the hand (Figure 7-5). The frequency of play in prone position (in and out of quadruped) strengthens the arms and hands. The infant shifts weight across the hands in a diagonal direction while moving from quadruped to side sitting (Boehme, 1988). Strengthening of the arms also occurs through pulling to stand and through supporting himself while erect (Figure 7-6). Postural stability increases such that the 12-monthold infant has greater control of arms in space while sitting independently. The internal stability of the arm allows the infant to prehend a small object using a superior pincer grasp (i.e., use a pincer grasp without
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Figure 7-5 Creeping on hands and knees provides tactile and proprioceptive input to hands.
Weight-bearing experiences continue to provide heavy work for the upper extremities. Creeping usually is the primary form of mobility. The infant may rise into the hands-and-feet position (bear crawling), resulting in heavy work for the arms. Fast creeping over a variety of surfaces provides important tactual and proprioceptive input to the hands. By 13 months the child’s balance and postural stability are sufficient for upright ambulation. Trunk rotation and pelvic stability are noted in smooth transitions from floor sitting to standing and from standing to sitting. Postural control can now support hand manipulation with arms in space, as observed in stacking blocks, placing objects in a container, and toy exploration. Now that upright ambulation is the child’s consistent form of mobility, upper extremity weightbearing experiences become limited and the hands no longer are critical for support, resulting in increased emphasis on their role in manipulation. Postural control is excellent by 2 years as the child begins to concentrate on speed, strength, balance, and endurance. Postural stability of the child at 24 months enables use of hands with control in all positions and planes around the body. Although dexterity diminishes when the child is in a less stable position (e.g., half kneel), postural stability in typical sitting and standing positions is sufficient for control of a great range of manipulative skills.
SENSORY SYSTEMS
Figure 7-6 arms.
Practice of pull-to-stand helps to strengthen
stabilizing the arm on the surface). Postural stability is an important factor in the development of an accurate and well-directed reach (Corbetta & Thelen, 1996). With increasing trunk stability and rotation the infant is able to reach to the body’s contralateral side. Postural stability also enables the child to reach overhead and behind when sitting.
The sensory systems that most influence hand skill development are visual, tactile, and proprioceptive. By the third month the head is held at midline, which frees the range of vision. During this same period the infant learns to control eye movements, and visual inspection becomes a key strategy for learning about the environment. Visual attention to specific events and objects indicates the infant’s ability to focus and assimilate important information from the environment (Bower, 1974; White, Castle, & Held, 1964). Although visual attention becomes more discriminating (von Hofsten & Rosander, 1996), hand skills remain primitive in that the hand does not adapt to the specific sensory qualities of the object it grasps, and control of release has not been established (Figure 7-7). The infant from birth through 3 months is often prone lying and has frequent opportunities for tactile or proprioceptive input to the hands and forearms. He presses into a prone propped position with the head erect, resulting in deep proprioceptive input to the arms. Hand opening while weight bearing, prone-onelbows, provides specific tactile input to the palms. Mouthing of the hand allows tactile exploration of the hand and provides tactile or proprioceptive input to the
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Figure 7-7
Hands conform to the object’s shape
Figure 7-9 Infant at 4 months explores a toy with hands and eyes.
Figure 7-8 Hands grasp at midline on his chest in 3month-old infant.
hand. When the infant is supine, the hands find each other on the chest, clasping and engaging in mutual fingering (Figure 7-8). These tactile or proprioceptive experiences contribute to the development of grasp and release patterns, as do the visual experiences that contribute to the development of visually guided hand movements. Sensory experiences continue to be a primary basis for movement in the 3- to 6-month-old infant. The infant delights in the sensory world and begins to integrate the information from more than one sensory system. Rochat (1987) reported that infants this age perceive hardness when compared with soft consistencies. Bushnell and Boudreau (1993) concluded that infants as young as 3 months can perceive hardness,
size, and temperature. Mouthing and fingering behaviors increase significantly from 3 to 6 months, increasing an infant’s perceptual learning (Ruff, 1984) (Figure 7-9). Fingering behaviors are associated with visual inspection. At 4 and 5 months of age infants increasingly make successive oral and visual contacts with the object, thereby integrating information from two different sensory systems. Beginning at 5 and 6 months, infants use both hands to explore objects. They explore textures, rotate and transfer objects, and alternate looking with mouthing (Rochat, 1989). Ruff and Kohler (1978) demonstrated that after 6-monthold infants tactually explore objects, they tend to visually prefer those objects. Their results provide evidence that an infant visually recognizes an object that was previously held and tactually experienced but not visualized. Sensory play at this time consists of mouthing, hand-to-hand fingering, and intense visual inspection. The role of vision in guiding manipulation has an increasingly important role after 6 months and then throughout development (Bushnell & Boudreau, 1991). Whereas tactile input had primary influence on grasp and manipulation, vision becomes a primary sense for guiding the infant’s manipulation. McCall (1974) reported an increase in manipulation with visual regard at 81⁄2 months. Castner (1932) observed that the duration of regard increased at 8 and 9 months, as did the infant’s accuracy in reach and grasp of a pellet.
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Figure 7-10 Infant at 8 months integrates visual and tactile information from toy with movable parts.
Active mouthing decreases as manipulation with visual regard increases in the second half of the first year (McCall, 1974). This active mouthing appears to be replaced with fingering. The increasing importance of vision in manipulation complements rather than diminishes the importance of the tactile system. The infant is now able to integrate visual and tactile information, using both senses simultaneously to learn about the object’s properties (Corbetta & Mounoud, 1990; Ruff, 1984) (Figure 7-10). lntermodal transfer of tactile and visual information (visual recognition of an object after handling it without vision) becomes possible at this age (Ruff & Kohler, 1978; Steele & Pederson, 1977). Changes in discrimination of the object’s weight and shape enable the 9- to 10-monthold child to hold a cracker without crushing it and lift an object with the appropriate amount of force. At 12 months the infant continues to use vision as a primary guide to object manipulation. The infant can visually recognize the physical properties of the object and act on it appropriately. For example, a 12-monthold infant bangs and hits a rigid object and squeezes or presses a spongy object (Bushnell & Boudreau, 1993; Gibson & Walker, 1984). Fingering and hand-to-hand manipulation become the primary modes for exploring the sensory qualities of an object (Ruff, 1984) (Figure 7-11). Integration of senses continues and the infant becomes increasingly able to recognize objects visually that had been explored only through the tactile sense. Infants learn anticipatory control; that is, they plan their
Figure 7-11 object.
Infant at 12 months visually explores
movements after visualizing the object. Anticipatory control means that the infant opens his hand according to the object’s size and shape before prehension. Through their prehension experiences infants also begin to anticipate the force necessary to grasp and lift an object (Gordon & Forssberg, 1997; Johansson & Westling, 1988). In the second year of life, the infant becomes interested in the functional use of objects and functional goals become the prime motive for manipulation (Gibson, 1988). The child continues to integrate visual, tactile, and proprioceptive sensations by practicing perceptual motor skills, demonstrating increased abilities to use information from these sensory systems to correct and refine movements. Thus increased precision of movement results from increased perceptual ability, as well as improved motor skill. The child can now recognize the tactile and auditory properties of the object through visual inspection and therefore approaches an object with an appropriate response (i.e., shaking a rattle, squeezing a sponge, crumpling paper, or using more force to lift a large object). By 2 years of age, improved sensory discrimination and integration enable the child to demonstrate increased variety and control of perceptual-motor skills. The 24-month-old child is able to assimilate multimodal sensory information and make appropriate adaptive responses. Success in perceptual-motor skills such as stringing beads and simple dressing tasks illustrates the child’s ability to integrate and use sensory information.
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DEVELOPMENT OF HAND SKILLS IN THE CONTEXT OF INFANT PLAY ACTIVITIES PLAY ACTIVITIES: BIRTH TO 12 MONTHS In the first months of life, infants delight in sensory experiences of touch and movement. Infants exhibit frequent generalized movements through which they gather multisensory input that increases arousal and attention. Play behaviors of young infants include swiping movements to cause a mobile to move and make sounds, or mouthing objects in perceptual exploration. When general swiping movements cause a mobile to move and make sounds, this sensory experience reinforces that action and the infant swipes at the mobile again. As noted in the previous section, visual exploration, mouthing, and tactile reflexes appear to be the infant’s primary methods for learning about the environment (Bower, 1974; Gesell et al., 1940) (Figure 7-12). The 4- to 6-month-old infant continues to delight in the sensory experiences of vision, touch, and movement. One goal of generalized movements and reactions appears to be creating sensory experiences. As the infant scratches the weight-bearing surface of the parent’s shoulder, this behavior seems to be automatically reinforced by the tactile and proprioceptive
input to the hand. He or she begins to actively explore objects using specific movements to create sounds and visual effects. By 6 months the infant can purposely roll and initiate rolling to experience movement. Toys that react to simple movements are favorites in play. Rattles are good examples, in that almost any movement produces a sound, reinforcing the infant’s play and exploration (Piaget, 1952). Toys that are activated by generalized responses continue to be preferred to those that require specific, more localized responses; for example, a rattle is preferred to a busy box requiring differentiated push, pull, and press of fingers (McCall, 1974). From 6 to 12 months, infants spend most of their playtime in object exploration. Interest in and awareness of the environment increases (as described in the previous section). Visual and tactile exploration of objects predominates. These exploratory behaviors are characterized by a rich variety of manipulative skills. Cause and effect are well established, and rather than repeating the same actions on a toy, the infant tries new strategies to create different reactions (Piaget, 1952). Play involves imitation of actions observed, including toy manipulation. The physical properties of the object guide responses, because the infant does not yet understand the specific functional uses of objects. The infant begins to bang objects together and place one object in proximity to another. These behaviors signal the advent of tool usage and specific actions of one object in relation to another (Bruner, 1970; Lockman, 2000). In the first year, infants also engage in social play that is focused on attachment, or bonding, to the primary caregivers. Infants play social games with parents and others to elicit responses. These may involve pat-acake, squeezes, and kisses. Although infants at this age engage readily with individuals other than family, they require their parents’ presence as an emotional base and return to them for occasional emotional refueling before returning to play. Therefore an infant remains near to caregivers, who assist in opening containers, turning knobs, and providing physical assistance as the infant investigates his environment (Pierce, 1997).
PREHENSION: BIRTH TO 12 MONTHS The prehension skills that infants develop in their first year of life serve their play goals and enable them to explore and learn about the environment. As infants’ play transitions from sensory-driven to functional, hand skills refine from generalized to precise patterns.
Primitive and Transitional Grasps Figure 7-12 Mouthing at 4 months is a primary method of object exploration.
Newborns tightly flex their fingers around a flexed thumb, only occasionally opening the hand in association with active extension of the trunk or arms. The neonate’s fisted hand is consistent with the overall
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predominance of physiologic flexor tone that dominates upper- and lower-extremity movements. He or she frequently brings the fisted hand to the mouth when prone, pulling the hands toward midline while assuming an overall flexed position. The first reflexive response of the arm and hand, termed the traction response, is demonstrated by the neonate when proprioceptive input or traction is applied to the arm. When the arm is pulled away from the body, synergistic flexion of the fingers, wrist, elbow, and shoulder results. As described by Twitchell (1970), stretch to the flexor and adductor muscles of shoulder is a sufficient stimulus for eliciting this response. In the first couple of weeks of life, the grasp reflex has not yet emerged. The neonate may posture with fisted hands, but responses to touch on the hands result in opening or partial opening. It is not until the second to fourth week of life that the infant automatically closes the fingers around an object (or adult’s finger) placed in his palm. This first grasp reflex requires that pressure (proprioception), as well as tactile input be applied to the palm and is accompanied by the traction response. A grasping reflex is not elicited in response to a visual stimulus. By 4 weeks the grasp reflex can be elicited with a contact stimulus to the palm or fingers. A moving stimulus is most effective in producing this local grasp reaction, which is immediately followed by the traction response. By 8 weeks two distinct phases of the grasp reflex are observed. The first is the catching phase, which is an immediate flexion of the fingers and thumb. In the second or holding phase the finger flexion is sustained. This holding is intensified if the object is lightly pulled. The traction response declines at this time but can be elicited when the arm is pulled from the body (Twitchell, 1970). By 3 to 4 months of age a true grasp reflex has developed and the traction response no longer automatically accompanies this response, although dorsiflexion of the wrist continues to accompany the finger flexion. When an object is placed in the hand and is moved medially, the fingers flex in a sustaining grasp. A palmar grasp is observed with the fingers flexing tightly and pressing the object into the palm. Although in past research an ulnar palmar grasp was documented to emerge first, more recent research shows that the index finger is active first and has a leading role in the first grasping patterns (Lantz, Melen, & Forssberg, 1996). The grasp reflex becomes diminished at 4 to 5 months of age and fractionation of the grasp reflex begins (Twitchell, 1970). One or two fingers flex in isolation from the others, given specific stimulation of their volar surfaces. At 5 to 6 months an instinctive grasp emerges, which combines the fractionated grasp and the orienting response (Twitchell, 1970). At this time the
infant not only orients to the stimulus by adjusting his forearm but actually gropes for a tactile stimulus. Groping for the moving object that is touching the hand occurs without visual input and can be observed in the child who has visual impairment (Corbetta & Mounoud, 1990). Therefore instinctive grasp includes following a moving stimulus to secure it and then adjusting the hand’s grasp to accomplish sustained holding of the object. Flexion of a single digit can be induced given isolated tactile contact. The instinctive grasp is a transitional behavior between primitive (reflexive) and mature patterns of movement, as the fractionated movements of the fingers and hand come under the infant’s voluntary control (Gilfoyle et al., 1990).
Purposeful Grasp The transitional behaviors described previously lead to the emergence of voluntary prehension (Gilfoyle et al., 1990). Between 4 and 6 months the infant develops control of grasp (Figure 7-13). Using both tactile and visual information, she becomes skillful in adjusting the hand to the object. The infant begins to use visual input to prepare the hand for grasp by opening and shaping the hand before grasp according to the object’s size and shape (Corbetta & Mounoud, 1990; Forssberg, 1998). These beginning abilities to grasp, orient, and adjust the hand to objects based on tactile and visual information signify the beginning of purposeful grasp. The infant becomes capable of using a variety of grasping patterns that are selected based on the affordances of
Figure 7-13
Palmar grasp at 6 months.
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 129 the objects and his or her playful intentions. Initially the infant uses only a few grasping patterns and uses them indiscriminately. As the infant gains experience and matures, a variety of patterns can be observed. At 20 weeks most infants touch, but do not grasp, a cube placed before them. The infant who successfully secures the cube does so by pulling it to the other hand or the body and squeezing it against another surface. Squeeze grasp develops by 20 to 24 weeks. The infant presses the cube using total finger flexion against the palm. Because his or her proprioceptive system and motor control remain crudely developed, the cube is squeezed tightly. Success in retaining the object is limited by his or her ability to adjust the object within the hand or differentiate finger movement. The thumb does not actively participate in this grasp and tends to lie in the palmar plane. Finger and hand movements without object grasp contribute to the development of grasp (Castner, 1932; Halverson, 1931). The 4- to 5-month-old infant often is observed scratching the supporting surface when prone on elbows. The infant uses alternating finger flexion and extension of the digits together. Scratching also may occur on the caregiver’s clothing when holding the infant upright against the shoulder. The scratching motion allows the infant to practice the full range of reciprocal finger flexion and extension. Scratching also provides the infant with rich tactile information about different textural surfaces. Halverson (1931) observed rubbing of the hand on the surface as an additional method for obtaining tactile input in the infant at 16 to 28 weeks. As the infant continues to use scratching, finger movements become differentiated such that one or two fingers move in isolation of the others. Halverson documented pianoing or “raising and lowering of each finger alternately” on the table in infants 16 to 24 weeks of age. Pianoing appears to be an automatic movement rather than a purposeful isolated motion of each digit. As with other hand skills, isolated movements of the fingers occur first in these automatic behaviors elicited by the sensory stimulation of the hand resting on a flat surface. A palmar grasp is most frequently used by the 24-week-old infant. The palmar grasp is characterized by a pronated hand and flexion of all fingers around the object. The thumb may slide around the object passively rather than actively holding it (see Figure 7-13). Halverson suggested that when thumb opposition first appears at 28 weeks, it is used only in association with a palmar grasp. By 28 weeks the infant holds the object in a radial palmar grasp (Gesell & Amatruda, 1947) or what Halverson (1931) termed a superior palmar grasp. The radial fingers and thumb press the cube against the palm (Figure 7-14). Therefore when held in a
Figure 7-14
Radial palmar grasp.
supinated hand, the object can be brought to and put into the mouth. The object can be banged against another surface, and the object becomes accessible for object transfer from hand to hand. The radial palmar grasp is a hallmark in grasp maturation because the infant now differentiates the sides of the hand, using the ulnar side to provide stability for the grasping movement and the radial side to prehend and hold the object. This early pattern signifies the initial development of radial fingers as the skill side of the hand. Knobloch and Pasamanick (1974) emphasized the versatility observed in manipulation patterns at 7 months: “He grasps it, brings it to his mouth, withdraws it again for inspection, restores it again for mouthing, transfers it to the other hand, bangs it, contacts it with the free hand, retransfers it, mouths it again, drops it, rescues it, mouths it again” (p. 60). Between 32 and 36 weeks the infant demonstrates grasp of the object in the fingers rather than the palm, and by 36 weeks the infant exhibits a radial digital grasp (Gesell & Amatruda, 1947) or inferior forefinger grasp (Halverson, 1931) (Figure 7-15). At this time the infant can prehend a small object between the radial fingers and thumb. With the object held distally in the fingers (proximal to the finger pads), the infant can adjust the object within the hand and as a result can use the object for various purposes while holding it. The adjustments allow for greater success in relating two objects or in bringing the object to the mouth for finger feeding. The movement of the object distally and to the radial fingers gives the infant greater control of the object and enables release control. When the 36-week-old infant grasps a very small object (pellet size), a scissors grasp is used. Gesell and
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Part II • Development of Hand Skills surfaces, in and on other objects. He also can use the index finger to turn or move the object before prehension to increase success in grasp. Along with increased accuracy in grasp at this time, by 1 year the infant requires less time to prehend an object, displaces the object less before grasp, and makes fewer adjustments to secure the object firmly in the hand.
OBJECT RELEASE: BIRTH TO 12 MONTHS
Figure 7-15
Radial digital grasp at 8 months.
Object release matures after early grasping patterns are achieved. Release is an integral part of prehension and manipulation, but involves extensor movement patterns that follow a slightly different developmental trajectory.
Automatic Release
Figure 7-16
Scissors grasp at 9 months.
Amatruda, as edited by Knobloch and Pasamanick (1974), defined a scissors grasp as prehension of a small object between the thumb and lateral border of the index finger after a raking movement of the fingers. The hand is stabilized on a surface during this grasp, and the ulnar fingers are flexed to provide stability of the thumb and radial finger movement (Figure 7-16). Forefinger grasp (Halverson, 1931) or inferior pincer grasp (Gesell & Amatruda, 1947) is observed at 40 weeks. This is a fingertip grasp in which the infant stabilizes the forearm on the table as a base while grasping the cube. The fingers that prehend the small object are more extended than flexed. By 52 to 56 weeks the infant prehends and holds the object between the thumb and forefinger tip. Successful prehension using a superior pincer grasp (Halverson, 1931; Illingworth, 1991) is achieved without the forearm stabilizing on the surface. At this time the fingers adjust to the size and weight of the object. The object is now in a position that it can be used readily in a play activity or as a tool. Because the infant no longer needs to stabilize to grasp, he can easily prehend objects from a variety of
As with grasp, the first object release observed is a reflexive behavior. Finger extension is observed as the neonate withdraws and abducts the fingers in response to touch of the hand (Twitchell, 1970). This response, termed the avoiding reaction, is usually only a slight withdrawal of the neonate’s hand. By 3 weeks and continuing to about 8 weeks, the avoiding response is elicited easily. When the dorsum of the hand is touched, the fingers abduct and extend. The hand also may pronate to withdraw from a contact stimulus. This response is elicited when the contact stimulus is lighter and more quickly applied than the firm palmar stimulation that elicits the grasp reflex. Twitchell (1970) described an instinctive avoiding response that is similar in nature to the instinctive grasp response, in that it represents a transitional behavior between reflexive and voluntary responses. The instinctive avoiding response emerges between 12 and 20 weeks of age. It is characterized by pronation and adduction away from a stimulus on the hand’s ulnar border and supination with abduction to stimulation of the hand’s radial side. The instinctive avoiding reaction generally is fully developed by 24 to 40 weeks of age (Twitchell, 1965, 1970). At this time the infant withdraws from light contact stimulation, using a variety of hand movements, including flexion, extension, abduction, adduction, and rotation. Avoiding reactions are seen more frequently when the infant is irritable or when generalized tactile defensiveness is present. The avoiding response serves as an automatic mechanism to reinforce hand opening and facilitate finger extension to balance the effects of the grasp reflex. According to Gesell and Amatruda (1947), release requires inhibition of the flexor muscles with contraction of the extensors, which is a more mature, later-developing neuromotor pattern. More recent theories (Thelen et al., 1987, Thelen & Smith, 1994) that recognize the interaction of systems in development attribute initial hand opening to per-
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 131 ceptual and biomechanical influences. The hand may first open with wrist flexion, which produces tension of the finger extensors. The hand also may open to rub or pat objects to perceive their sensory qualities (Bushnell & Boudreau, 1993).
Purposeful Release From 5 to 6 months the infant begins a transition from reflexive to purposeful release. The infant demonstrates release accidentally or involuntarily in association with movements, tactile stimulation to the hand, or contact with another surface. At 6 months release is observed during mouthing and bimanual play. The infant brings an object or finger food to the mouth with both hands and may release one or both once the object is stabilized in the mouth. When the infant holds an object with two hands, one hand may fall from the object. Meanwhile, the infant practices finger extension in other activities. For example, extended fingers may be observed in patting the bottle or toy (Figure 7-17). Additional facilitation of finger extension in the 6- and 7-month-old child (see Figure 7-2) also occurs in the prone-on-hands position. At 28 weeks, the child releases an object when transferring it from one hand to the other. Initially object transfer is achieved by holding the object at midline with both hands and pulling it out of one hand into the other. Therefore the release is actually a forced withdrawal accomplished by the opposite hand. During this same developmental period the infant releases an object on a table surface or another resisting (Gesell & Amatruda, 1947) or assisting (Ammon & Etzel, 1977) surface. Release with the assistance of another surface enables the child to roll the object from the fingers or remove it from the hand by inhibiting finger flexion (i.e., without active extension). Between 40 and 44 weeks the infant demonstrates purposeful release in the context of play (Illingworth, 1991; Knobloch & Pasamanick, 1974). This first active
Figure 7-17
Fingers extend as infant pats toy.
release is often accomplished by flinging the object— combining elbow, wrist, and finger extension in a synergistic, ballistic movement. The infant now purposefully drops food and toys from his or her highchair and takes great pleasure in practicing this newfound skill. The object is released with the hand above the table surface, using full finger and thumb extension. Object-releasing activity is reinforced by the auditory and visual consequence of dropping the object. This new skill is also reinforced by the development of object permanence and the infant’s interest in observing objects disappear and reappear. By 52 weeks the infant demonstrates greater proficiency in releasing the object. With increasing control of finger extension, the infant begins to demonstrate graded hand opening when releasing. At this time she is practicing precision release for stacking one block on another or placing a form in its form space. Graded hand opening with controlled finger extension is first observed with the proximal hand base and forearm stabilized on a surface.
BIMANUAL SKILLS: BIRTH TO 12 MONTHS Humans are essentially bimanual beings from birth and most movement patterns of the arms and hands involve combined movements of both. Fagard and Jacquet (1996) indicated that bilateral arm movements are the predominant pattern of upper extremity movement throughout the first year of life. Two hand actions generally follow prehension and although varied, follow a developmental sequence. The sequence of bimanual skills observed during infancy relates to the infant’s postural, sensory, perceptual, and cognitive development, as well as hand skill development.
Early Development of Bilateral Arm Movements The neonate exhibits both asymmetric and symmetric limb movements. Some of these are associated with the asymmetric tonic neck reflex; many appear to be random. Smooth, alternating arm and leg movements are most characteristic, with specific reflexive behaviors elicited by specific tactile input. The first bimanual reach toward an object may be observed at 2 months (White et al., 1964), although swiping at objects tends to be unilateral. By 3 months swiping increases and hand-to-hand interplay, without an object, is observed with hands clasped on the chest (see Fig 7-8). The infant may involuntarily hold an object on the chest at midline, resulting from the clasping of the hands together. Most spontaneous arm and hand movements appear to be simultaneous and symmetric. At 16 weeks this symmetry continues to predominate, although one hand tends to lead the other. Usually the hands join together at midline, and the
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Figure 7-18
Symmetric arm movements at 4 months. Figure 7-19
object is held between them (Figure 7-18). Almost universally, once the object is prehended, the infant brings it to the mouth or chest. The object may drop when transported to the mouth or may be captured against a body part. These behaviors are reinforced by the infant’s drive toward symmetric midline movements at this age and the desire to experience oral sensation. Lack of internal trunk stability at 4 months also results in bringing both hands together around the object for distal stability. The 20-week-old infant tends to use the simultaneous approach described earlier, in which both hands move toward the object at the same time. The infant attempts to prehend the object using both hands (Castner, 1932). Although the 5-month-old infant reaches for the object with two hands, he uses only one to grasp the object (Fagard & Peze, 1997). The second hand may support the first after grasp is achieved, and often both hands bring the object to the mouth or hold it in space for visual inspection. Intermanual transfer has significantly increased (Rochat, 1989), although active purposeful release has not yet developed. Compared with 2- and 3-month-olds, 4- and 5-month-old infants demonstrate significantly better organized bimanual action with more holding and fingering of objects, The bilateral fingering behavior observed at this age has been described as grasping the object with one hand and touching it or scanning the object’s surface with the other (Ruff, 1984).
Transitional Bilateral Skills Between 24 and 28 weeks the infant approaches the cube most frequently with both hands, corralling it. During this developmental period first a simultaneous, then a successive bilateral approach is used. The infant
Unilateral approach to grasp object.
initiates movement in the second hand as the first hand ends its approach (Castner, 1932). Bilaterality versus unilaterality in approach seems to be determined by the object’s size and the way it is presented. The 7-month-old infant uses a bilateral approach for large objects and a unilateral approach for small objects (Fagard, 1998) (Figure 7-19). Other authors suggest that approach is determined by the external support provided for the infant’s proximal stability during reach (Bushnell, 1985; Halverson, 1931). After grasping the object, the infant visually inspects it or brings it to the mouth. She may transfer it using the mouth as a stabilizer. The 7-month-old infant uses primarily bilateral movements for object manipulation (Goldfield & Michel, 1986; Flament, as cited in Corbetta & Mounoud, 1990). At this time the infant demonstrates associated, rather than independent, bimanual movements. Although the two hands act in concert, an increasing variety of exploratory and manipulative behaviors are observed (Figure 7-20). For example, the infant uses an extended index finger to poke or probe an object held in the other hand. This probing with one hand while holding with the other is a primary method of object exploration. As mentioned, by 7 months the infant holds the object in the radial digits and actively transfers it from hand to hand, while visually and tactilely exploring it. Active supination and isolated wrist movements enable the infant to partially rotate or turn the object for visual inspection. These isolated movements often are mimicked by the other hand. Manipulation of the object at this time is limited to transfers from hand to
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 133
Figure 7-20 movements.
Two hands explore in associated bimanual
Figure 7-21 toys.
A 7-month-old infant continues to mouth
A
B
hand or hand to mouth rather than within hand manipulation. Mouthing remains an important part of the infant’s exploration (Figure 7-21). After 7 months of age, infants begin to play with two toys at a time (Figure 7-22). The infant bangs two objects together as the first indication of her capacity to associate objects (Corbetta & Mounoud, 1990). In the following weeks the infant adds to the repertoire of bilateral movements. In addition to visual inspection and hand-to-hand exchange, the infant waves toys in the air and bangs them on the table surface. By 9 months the striking change in manipula-
Figure 7-22 A, B. Infants can hold two objects simultaneously by 7 months.
tion is not related to the development of any specific skill, but to the expanded range of behaviors observed. Now one hand holds the object and the second hand manipulates the object. In “complementary bimanual activities,” one hand positions the object and the other manipulates parts of it (Bruner, 1970). Halverson (1931) noted that 9-month-olds “exhibited all of the following behaviors: transfer, visual inspection, release and regain, bang it on the table, and hold it with both hands.” By 9 months object rotation, primarily achieved by transferring from hand to hand, allows the infant to perceive the shapes of objects (Lederman &
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Klatzky, 1987). This type of rotation is possible because of increasing control of the radial digits and ability to grade supination and pronation as the object moves from hand to hand. This two-hand cooperation in turning an object is evidence of beginning dissociation of symmetric arm movements. Near the end of the first year a change is observed in the linkage between two-hand movement (Goldfield & Michel, 1986). Whereas 7-month-old infants move their hands in the same direction, 11-month-olds move them in complementary directions. This change marks the initiation of mature bimanual skills.
Coordinated Bimanual Skills At 12 months the infant demonstrates significant increases in both dexterity with one hand and cooperative use of two hands together. Ruff (1984) observed an increase in fingering by 12 months, which she associated with an increase in the infant’s ability to simultaneously assimilate tactile and visual information. The two hands begin to demonstrate coordinated asymmetric roles (Figure 7-23). These complementary movements are observed as the infant simultaneously holds two objects or an object and a container. A typical bilateral pattern at this time is for one hand to be active (generally the preferred hand) and one hand to be passive or to support and stabilize the object (e.g., one hand holds the container while the other removes a block inside). Bruner (1970) studied the success of infants in removing a toy from a toy box. He found that before 12 months infants are rarely successful in removing the object. Beginning at 12 months the hands work in cooperation; for example, one hand holds the bottle and the other unscrews the lid. These complementary functions are flexile and adaptable, enabling the hands to work together for functional
Figure 7-23 Play includes distinct yet complementary movement of each hand.
purposes. Flexible bimanual skills that can combine in numerous patterns, switching roles in a sequence of movements, develop in the second and third year as the child’s play repertoire expands.
PLAY ACTIVITIES: 12 TO 24 MONTHS The 1-year-old infant has developed an understanding of an object’s functional purpose, thereby attempting to use objects for the function for which they are intended. For the first time the infant’s repertoire of manipulative skills increases, in accordance with functional capabilities of the object more than its sensory qualities. The infant pushes a truck, pulls a toy dog on a string, lifts a telephone receiver to the ear, rolls a ball, and lifts a brush to the hair. All of these movements are based on emerging cognitive understandings, as functional play begins to predominate over sensory play. The child’s interest in relating two objects also results in more advanced unilateral and bilateral skills. Endless repetitions of putting objects in a container and placing one object next to another create interesting results for the infant and at the same time refine releasing skills. New skills in imitation are a basis for developing additional manipulation skills as the infant attempts new movements that he observes others perform. The child’s play between 18 and 24 months continues to focus on concrete, functional activities with toys. Play sequences increase in length and complexity. Symbolic play begins about the same time that language develops, between 16 and 20 months. At first the infant demonstrates self-play that is centered around or directed toward the self (Belsky & Most, 1981). The child’s play might consist of simulating eating, drinking, or sleeping. These self-directed actions signal the beginning of pretend play (Piaget, 1952). The child knows cause and effect and repeatedly makes the toy telephone ring or the battery-powered doll squeal to enjoy the effect of the initial action. By 2 years, the child’s symbolic play becomes directed to objects. This decentered play involves acting on dolls or teddy bears, feeding them, putting them to bed, combing their hair. The hand skills to perform such actions are complex and require that a series of related movements be linked together. These play activities are thus an integrated combination of bimanual skills, most of which require that one hand holds and the other acts on the object. By the end of the second year, play has expanded in two important ways. First, the child begins to combine actions into play sequences (e.g., he or she relates objects to each other by stacking one on the other or lining up toys beside each other). These combined actions show a play purpose that matches the various
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 135
Figure 7-24
Functional play with a toy car.
functions of the toy. Second, 2-year-old children now direct actions away from themselves. The objects used in play generally resemble real-life objects (Linder, 1993). The child places the doll in a toy bed and then covers it. The child pretends to feed a stuffed animal or drives toy cars through a toy garage. At 2 years of age, play remains a central occupation of the child, who now has an increased attention span and the ability to combine multiple actions in play. The emergence of symbolic or imaginary play with toys and objects offers the first opportunities for the child to practice the skills of daily living (Parham & Primeau, 1997; Reilly, 1974). As the infant learns more about the capabilities and affordances of objects, his play become more elaborate. His manipulation skills match his need to open and combine objects in novel ways, sometimes imitating parents and peers and sometimes experimenting with object properties. In general, the functional purpose of toys determines the toddler’s response: dialing the phone, turning the music box, unzipping a zipper, scribbling with a crayon, or pushing a car (Figure 7-24). With an increased interest in relating multiple objects, the child fills a container with small objects, places one object on or next to another, and scoops food with a spoon. These relational play activities often require stabilizing the toy or object with one hand while manipulating with the other. The child’s understanding of cause and effect and object permanence results in increased interest in switches, hinges, push buttons, and pop-up toys. Switches require elaboration of the prehensile patterns developed and new combinations of arm and hand movements. Most play activities now require bimanual skills, and the child is able to use hands together simultaneously or reciprocally (Corbetta & Mounoud, 1990) (Figure 7-25). The child engages in longer and more complex play sequences that
Figure 7-25 Blended mobility and stability and use of isolated finger movements.
Figure 7-26 Cup drinking as an example of coordinated hand movements for a functional goal.
require new combinations of hand skills. Pushing, pulling, probing, rotating, and turning are combined into a new repertoire of play behaviors (Nicholich, 1977). With new understanding of tool use, the child engages in play activities that require mobility of the proximal arm and stability of the hand for grasping the object (Exner, 2005). The functional use of some objects, such as a cup, requires a series of combined mobility and stability of the arm and hand (Figure 7-26). The functional play that characterizes the child at this age correlates with an increasing purposefulness
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Figure 7-27
Spoon feeding at 18 months.
in manipulation. Although the child continues to explore objects to learn their sensory properties, she also often “uses” objects for their specific function as part of a purposeful play activity. The 2-year-old child uses utensils with competency. He now has sufficient control of crayon or pencil grasp to make a vertical stroke. Most children insist on selffeeding at this stage. Although early attempts to spoon feed generally fail, the intent is clear. Self-feeding becomes more successful because the child does not turn the spoon as it enters the mouth (Figure 7-27). Spoon feeding and early drawing skills are made possible by integration of sensory and perceptual information into blended patterns of mobility and stability. With improved perceptual-motor integration, the child imitates a circular stroke, matches a form to a form space, holds an object with appropriate pressure, places and releases an object with accuracy, and demonstrates beginning eye–hand coordination in ball play. All of these skills indicate an increased ability to integrate sensory experience and make accurate motor responses or adaptations to those sensory inputs (Connolly & Dalgleish, 1989).
PREHENSION: 12 TO 24 MONTHS By 60 weeks prehension is deft and precise. The child plans and uses grasping patterns that enable him or her to act on the object after prehension (Gesell & Amatruda, 1947). Fingertip grasp is used unless the object is large and heavy or the situation is stressful for the child (e.g., being off balance or hurried). The hand is sufficiently differentiated to hold two cubes in one hand (Knobloch & Pasamanick, 1974). The child can
move different parts of the hand (i.e., the radial and ulnar sides) independently and can control the action of isolated fingers. Gesell described the grasp of an 18-month-old child as enveloping rather than manipulative. At this age thumb opposition is good; however, the hand remains primarily a prehender rather than a manipulator. Exploration of the object requires both hands and involves transferring and turning the object from one hand to the other. At this time the infant is able to adjust grasp to accommodate the weight and shape of the object (Gordon & Forssberg, 1997). This enables holding a cracker without crushing it. The infant has increasing ability to differentiate the pressure used in finger flexion, indicating increased tactile and proprioceptive discrimination in addition to greater motor control. The 24-month-old child demonstrates increasing dissociation of the fingers, strength and control of the hand’s arches, and sensitivity to the tactual properties of the object. These underlying hand skills enable the child to perform a great variety of functional skills (e.g., self-feeding, using a spoon, scribbling with a crayon, building a tower of three cubes, and turning pages of a book). Practice of these skills leads to emergence of the pretend play sequences that dominate by 3 and 4 years.
OBJECT RELEASE: 12 TO 24 MONTHS The need to stabilize a proximal hand or arm part on a surface to accomplish controlled release (e.g., release cubes in a cup) continues through 18 months. In particular, more precise release (e.g., of a small object) requires the support of a stabilizing surface (Knobloch & Pasamanick, 1974). Release of a cube in building a three-cube tower is practiced, and, although generally successful, alignment of the cubes is imprecise. Typically, when stacking cubes or small blocks, the infant extends the fingers all at one time, using more extension than is necessary to actually release the object. The infant’s release is graded rather than abrupt, and small wrist, forearm, and finger movements are used to adjust the positions of the cubes one on the other. Visual inspection during release increases, such that the hand can accurately place a cube or puzzle piece. Perhaps the most important contribution to the infant’s ability to place one object on another is internal stability of the arm while it is held in space, which allows the hands to act independently. By the end of the second year the child has welldeveloped internal proximal stability and smooth graded or incremental release patterns. He can open the hand partially while carefully monitoring whether the object is correctly placed. Therefore the infant is
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 137 now able to adapt and adjust the hand opening according to the size, shape, and weight of the object. Controlled release in the 2-year-old child enables him to fit puzzle pieces into their form space, place small objects in a container, turn pages of a book, stack blocks, and manage a cup and feeding utensils. He can construct a six-cube tower by precisely centering each cube and slowly releasing it, using gradual extension of his fingers. Object release continues to develop over the next 3 years with significant increases in steadiness, precision, dexterity, and speed.
BIMANUAL SKILLS: 12 TO 24 MONTHS From 12 to 24 months the infant develops greater control of bimanual skills with increasing complexity and integration of motor patterns. Speed, accuracy, and dexterity increase. Proximal arm movements become dissociated from distal arm movements such that the infant can hold the hands in space to manipulate objects. He or she also can demonstrate controlled arm movement while maintaining grasp of an object (Exner, 2005). Many of the child’s activities involve one hand manipulating and the other stabilizing the object. For example, the child begins to spoon feed while holding the bowl, scribble with a marker while holding the paper, bang with a toy hammer while stabilizing the target toy. Between 18 months and 2 years the child learns a variety of bimanual skills that require control of simultaneous hand movements involving blended combinations of alternating stability and mobility (Gilfoyle et al., 1990). Stringing beads, pulling off shoes, and unwrapping a piece of candy are examples of skills in the repertoire of the 2-year-old that involve a sequence of bimanual movements in which the child simultaneously controls arm and hand stabilization and movement (Knobloch & Pasamanick, 1974). These bimanual movements can be asymmetric and dissociated when the activity requires that two hands act together in different movements. Two-handed simultaneous movement also represents a developmental step from the earlier pattern of one hand manipulating and the other stabilizing. Cooperative and complementary bimanual movements continue to be added to the child’s repertoire of fine motor skills throughout the
first decade of life. The complexity, speed, accuracy, and precision of the skills increase with experience, cognitive development, and neuromotor maturation. Table 7-1 presents the developmental sequence of grasp, release, and bimanual skills. Although the developmental ages for the listed skills vary, the sequence of development tends to remain consistent across children; therefore the months listed are estimated ages when the described skills are achieved.
SUMMARY The child’s play and the hand skills that enable that play undergo tremendous developmental changes in the first 2 years of life. Exploratory play skills evolve from generalized movements that gather comprehensive sensory input to specific exploration of the sensory qualities of objects. After the first year of life, infants exhibit functional play skills in which objects are used as means toward a functional goal. Infants learn to use tools as evidence of their expanding knowledge about how objects relate and how tools can serve functional goals. As play skills mature, the infant’s crude prehension patterns become precise grasping patterns that enable skillful manipulation of objects. The child holds objects first in the palm, then in the fingers, and finally in the fingertips. As she holds objects more distally, coordination of two hands together evolves, enabling the child to achieve greater competence and skill in play and interaction within the environment. This chapter described how hand skills evolve from reflexive, stereotypical patterns into precise, well-controlled prehension and manipulation patterns. Current research has investigated how the infant develops hand skills. Posture, sensory functions, and perception appear to have essential roles in hand skill development. The activities and environments that surround the infant afford a multitude of manipulation opportunities. Current explanatory models explain how hand skills develop and elucidate what variables influence an infant’s developmental trajectory. These models emphasize the influence of contextual elements in addition to biological foundations and have application in early childhood intervention and education.
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Table 7-1
Development of grasp, release, and bimanual skills: birth through 24 months
Approximate Age
Grasp
Release
Bimanual Skill
Neonate
Traction response
Avoiding reaction: hand opens with tactile stimulus to hand’s dorsum
Smooth, alternating arm movements; reflexive arm responses to proprioceptive and tactile input
1 months
Grasp reflex: local grasp reaction, followed by traction response
Avoiding reactions continue
Asymmetry of arm reaction; reflexive arm responses to proprioceptive and tactile input
2 months
Grasp reflex: catch and holding phases Instinctive avoiding response; pronation and adduction from stimulus on ulnar side, supination, abduction from stimulus on radial side
Hands held together on chest, usually without object; symmetric, simultaneous arm movement
3 months
4 months
True grasp reflex; primitive squeeze of fingers; diminished traction response; orienting response
Instinctive avoiding reactions continue; variety of hand movements used to avoid touch contact
Objects held with both hands at midline; symmetric, midline movements
5 months
Instinctive grasp; squeeze grasp, gropes for tactile stimulus; adjusts hand to object
Release involuntary or accidental
Two-hand reach, with unilateral prehension; object transfer, hand to hand; bilateral holding and fingering
6 months
Palmar grasp; pronated hand and flexion of all fingers; adjusts hand using visual and tactile information
Object accidentally released in mouthing or bimanual play
Simultaneous, symmetric, bilateral approach with bimanual or unilateral prehension
7 months
Radial palmar grasp; superior palmar grasp; differentiation of ulnar and radial sides stable; radial fingers hold object
Purposeful release; transfer of object from one hand to the other; release against a resisting surface
Successive bilateral approach with unilateral prehension; bilateral object manipulation; associated bimanual movements
8 months
Radial digital grasp; inferior forefinger grasp; object held proximal to finger pads; ulnar side stable and radial fingers hold object
Purposeful release with assistance or resistance against a surface
Continued
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 139
Table 7-1
Cont’d
Approximate Age
Grasp
9 months
Scissors grasp; able to hold small objects
10 months
Forefinger grasp; tip of thumb and forefinger used in grasp; grasping accuracy without stabilization
Release
Bimanual Skill Object rotation by transferring it hand to hand; plays with two toys, one in each hand, banging together; dissociation of symmetric arm movement
Active release; flinging of object by combining elbow, wrist, and finger extension; object release above surface
11 months
Complementary and cooperative bimanual movement
12 months
Superior pincer grasp; tip of thumb and forefinger used in grasp; grasping accuracy without stabilization
Beginning of controlled release; remains imprecise
Coordinated, asymmetric movements; one hand stabilizes and one hand manipulates
15 months
Deft and precise grasp; a variety of grasps used
Controlled release; increasing control when releasing
Beginning of two-hand tool use; continues pattern of one hand stabilizing and one manipulating
18 months
Increasing dissociation, strength, and perception enable child to use tools and manipulate objects
Controlled release, increasing accuracy with limited precision of placement; tends to extend fingers all at one time
Asymmetric, dissociated bimanual skills; blended stability and mobility; alternating sequences of two-hand movements
Greater precision and control of release; adjustment of hand opening according to object’s size and shape
Increasing competence in two-hand tool use; increasing complexity in movement patterns; cooperation of two hands
24 months
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Exner C (2005). The development of hand skills. In J CaseSmith (editor): Occupational therapy for children, 5th ed. (pp. 304–355). St Louis, Mosby. Fagard J (1998). Changes in grasping skills and the emergence of bimanual coordination during the first year of life. In DJ Connolly (editor): The psychobiology of the hand (pp. 123–143). Cambridge, UK, Cambridge University Press. Fagard J, Jacquet AY (1996). Changes in reaching and grasping objects of different size between 7 and 13 months of age. British Journal of Developmental Psychology, 14:65–78 Fagard J, Peze A (1997). Age changes in interlimb coupling and the development of bimanual coordination. Journal of Motor Behavior, 29:199–208. Forssberg H (1998). The neurophysiology of manual skills development. In KJ Connolly (editor): The psychobiology of the hand (pp. 123–141). Cambridge, UK, Cambridge University Press. Gesell A (1928). Infancy and human growth. New York, Macmillan. Gesell A, Amatruda CS (1947). Developmental diagnosis. New York, Harper & Row. Gesell A, Halverson HM, Thompson H, Ilg PL, Castner BM, Ames LB, Amatruda CS (1940). The first five years of life. New York, Harper & Brothers. Gibson EJ (1988). Exploratory behavior in the development of perceiving, acting, and the acquiring of knowledge. Annual Review of Psychology, 39:1–41. Gibson EJ, Walker AS (1984). Development of knowledge of visual-tactual affordance of substance. Child Development, 55:453–460. Gibson JJ (1979). The ecological approach to visual perception. Boston, Houghton-Mifflin. Gilfoyle E, Grady A, Moore J (1990). Children adapt, 2nd ed. Thorofare, NJ, Slack. Goldfield EC, Michel GP (1986). The ontogeny of infant bimanual reaching during the first year. Infant Behavior and Development, 9:81–89. Gordon AM, Forssberg H (1997). Development of neural mechanisms underlying grasping in children. In KJ Connolly, H Forssberg (editors): Neurophysiology and neuropsychology of motor development (pp. 214–231). London, MacKeith Press. Gottlieb G (1992). Individual development and evolution: The genesis of novel behavior. New York, Oxford University Press. Halverson HM (1931). An experimental study of prehension in infants by means of systematic cinema records. Genetic Psychology Monographs, 10:107–286. Halverson HM (1932). A further study of grasping. Journal of General Psychology, 7:34–63. Halverson HM (1937). Studies of the grasping responses of early infancy. Journal of Genetic Psychology, 51:371–449. Illingworth RS (1991). The normal child: Some problems of the early years and their treatment, 10th ed. Edinburgh, Churchill Livingstone. Johansson RS, Westling G (1988). Coordinate isometric muscle commands adequately and erroneously programmed for the weight during lifting task with precision grip. Experimental Brain Research, 71:59–71. Jones MC (1926). The development of early patterns in young children. Pedagogical Seminar, 33:537-585.
Hand Skill Development in the Context of Infants’ Play: Birth to 2 Years • 141 Knobloch H, Pasamanick B (1974). Gesell and Amatruda’s developmental diagnosis: The evaluation and management of normal and abnormal neuropsychologic development in infancy and early childhood. Hagerstown, MD, Harper & Row. Lantz C, Melen K, Forssberg H (1996). Early infant grasping involves radial finger. Developmental Medicine and Child Neurology, 38:668–674. Lederman SJ, Klatzky RL (1987). Hand movements: A window into haptic object recognition. Cognitive Psychology, 19:342–368. Linder T (1993). Transdisciplinary play-based assessment. Baltimore, Brooks. Lockman JJ (2000). A perception-action perspective on tool use development. Child Development, 71:137–144. Manoel EJ, Connolly KJ (1998). The development of manual dexterity in young children. In KJ Connolly (editor): The psychobiology of the hand (pp. 177–198). Cambridge, UK, Cambridge University Press. London, MacKeith Press McCall RB (1974). Exploratory manipulation and play in the human infant. Monographs of the Society for Research in Child Development, 39:155. McCarty ME, Clifton RK, Collard RR (1999). Problem solving in infancy: The emergence of an action plan. Developmental Psychology, 35:1091–1101. McCarty ME, Clifton RK, Collard RR (2001). The beginnings of tool use by infants and toddlers. Infancy, 2(2):233–256. McGraw MB (1943). The neuromuscular maturation of the human infant. New York, Columbia University Press. Newell KM, MacDonald PV (1997). The development of grip patterns in infancy. In KJ Connolly, H Forssberg (editors): Neurophysiology and neuropsychology of motor development (pp. 232–256). Cambridge, UK, Cambridge University Press. Nicholich L (1977). Beyond sensorimotor intelligence: Assessment of symbolic maturity through analysis of pretend play. Merrill-Palmer Quarterly, 23:89–102. Parham D, Primeau L (1997). Play and occupational therapy. In D Parham, L Fazio (editors): Play in occupational therapy for children (pp. 2–22). St Louis, Mosby. Peterson SM, Albers AB (2001). Effects of poverty and maternal depression on early child development. Child Development, 72:1794–1813. Piaget J (1952). The origins of intelligence in children. New York, Norton. Pierce D (1997). The power of object play for infants and toddlers at risk for developmental delays. In D Parham, L Fazio (editors): Play in occupational therapy for children (pp. 86–111). St Louis, Mosby. Reilly M (1974). Play as exploratory learning. Beverly Hills, Sage. Rochat P (1987). Mouthing and grasping in neonates: Evidence for the early detection of what hard or soft substances afford for action. Infant Behavior and Development, 10:435–449. Rochat P (1989). Object manipulation and exploration in 2- to 5-month-old infants. Developmental Psychology, 25(6):871–884.
Ruff HA (1984). Infants’ manipulative exploration of objects: Effects of age and object characteristics. Developmental Psychology, 20:9–20. Ruff HA (1989). The infant’s use of visual and haptic information in the perception and recognition of objects. Canadian Journal of Psychology, 43:302–319. Ruff HA, Kohler CJ (1978). Tactual-visual transfer in sixmonth-old infants. Infant Behavior and Development, 1:259–264. Santos DC, Gabbard C, Goncalves VM (2001). Motor development during the first year: A comparative study. Journal of Genetic Psychology, 162(2):143–153. Shirley MM (1931). The first two years: A study of twenty five babies, vol. 1. Locomotor development. Minneapolis, University of Minnesota Press. Smith LB, Thelen E (2003). Development as a dynamic system. Trends in Cognitive Science, 7:343–348. Steele D, Pederson DR (1977). Stimulus variables which affect the concordance of visual and manipulative exploration in six-month-old infants. Child Development, 48:104–111. Thelen E (1995). Motor development: A new synthesis. American Psychologist, 50(2):79–95. Thelen E, Corbetta D, Kamm K, Spencer JP, Schneider K, Zernicke RF (1993). The transition to reaching: mapping intention and intrinsic dynamics. Child Development, 64:1058–1098. Thelen E, Kelso JAS, Fogel A (1987). Self organizing systems and infant motor development. Developmental Review, 7:39–65. Thelen E, Smith LB (1994). A dynamic systems approach to the development of cognition and action. Cambridge, MA, MIT Press. Thelen E, Spencer JP (1998). Postural control during reaching in young infants: a dynamic systems approach. Neuroscience and Biobehavioral Reviews, 22:507–514. Twitchell TE (1965). Normal motor development. Journal of the American Physical Therapy Association, 45:419–423. Twitchell TE (1970). Reflex mechanisms and the development of prehension. In K Connolly (editor): Mechanisms of motor skill development. London, Academic Press. Van der Fits IBM, Hadders-Algra M (1998). The development of postural response patterns during reaching in healthy infants. Neuroscience and Biobehavioral Reviews, 22:75–85. von Hofsten C (1986). The emergence of manual skills. In MG Wade, HTA Whiting (editors): Motor development in children: Aspects of coordination and control (pp. 167–185). Boston, Martinus Nijhoff. von Hofsten C, Rosander K (1996). The development of gaze control and predictive tracking in young infants. Vision Research, 36:81–96. White BL, Castle P, Held R (1964). Observations on the development of visually directed reaching. Child Development, 35:349–364. Yim SY, Cho JR, Lee IY (2003). Normative data and development characteristics of hand function for elementary school children in Suwon Area of Korea: Grip, pinch and dexterity study. Journal of Korean Medical Science, 18:552–558.
Chapter
8
OBJECT MANIPULATION IN INFANTS AND CHILDREN Charlane Pehoski
CHAPTER OUTLINE OBJECT MANIPULATION DURING INFANCY Movements Used in Object Exploration by Infants Exploratory Nature of Infant Object Manipulation Object Exploration by the Mouth and Hand Role of Vision in Infant Object Manipulation Handling Multiple Objects Summary and Therapeutic Implications OBJECT MANIPULATION DURING THE TODDLER YEARS Beginning of In-Hand Manipulation Control over Object Release Complementary Two-Hand Use Summary and Therapeutic Implications OBJECT MANIPULATION IN THE PRESCHOOL AND EARLY CHILDHOOD YEARS Studies of In-Hand Manipulation Role of Variability in Motor Skill Development Factors Contributing to the Improvement of In-Hand Manipulation Skills Summary and Therapeutic Implications OBJECT MANIPULATION IN OLDER CHILDREN SUMMARY
The hand is a wonderful tool that has the exploration and manipulation of objects as its primary purpose. The development of the hand in the service of object manipulation follows a long course. It is one of the ways
children experience success and the perception of competence. Bruner (1973) pointed out that competence includes not only social interaction but also mastery over objects. The theme of this chapter is how the child gradually gains control over the hand to manipulate objects. Infancy appears to be a time when reach is perfected and the basic grasp patterns are developed. At first the infant can manipulate objects only by grasping the object, waving the arm, and moving the wrist because the object is held in a power grip that fixes it in the hand (Napier, 1956). Gaining the ability to transfer an object hand to hand greatly expands the actions the infant can produce with the object, but it is the appearance of a precision grip (pad of radial fingers to pad of thumb) that marks a major change in the eventual skills of the hand. Landsmeer (1962) indicated that the purpose of a precision grip is to “operate the object with precision by means of the fingers.” The perfection of this skill covers a long developmental period. Voluntary release (e.g., releasing an object in a predetermined place) also develops in late infancy and is an important component to skilled object interaction. Like object release, many of the basic components for skilled hand use are seen during infancy, but their perfection takes many years. As an example, the child must learn to control the release of an object so he or she can place it with skill and accuracy. In-hand manipulation skills, or the movement of an object in the hand after grasp, are yet to be acquired, and although the infant has the rudiments of two-hand use, the ability to plan the movements of both hands at the same time is not yet present. This chapter discusses what is known about the development of these components. There are many gaps in our understanding of these changes and how they might impact on the child’s gradual mastery of the
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physical world. Given the importance of object manipulation to human behavior, it is interesting that so little study has been done on this motor skill. In looking at what has been written, we divided the children into four age groups: infancy (neonate to 12 months old), toddler (1 to 2 years old), preschool/ early childhood (3 to 6 years old), and the older child. In addition, themes that might help us understand the direction skilled hand use is taking at each of these stages are explored. One last note: The hand is the tool of the mind. It is the mind that directs and guides the hand in the context of the child’s environment and culture. Object exploration or manipulation is the result of our desire to master the physical world. In infancy the basic drive to explore the world is present and, although the infant’s physical skills are limited, these skills are used to gain information about object properties. It is probable that this drive sets the stage for all future object exploration and the continued drive toward mastery.
OBJECT MANIPULATION DURING INFANCY Manipulation implies that the movement of the object is done to achieve some purpose or goal; that is, that the individual is consciously engaged in the activity and directing the action. By this definition, there was a time when researchers would not have considered studying object “manipulation” in the very young infant. Neonates and young infants were considered to be primitive beings dominated by reflexes that would gradually be integrated so the infant could engage the world. More recent research has been guided by the belief that infants are born curious and with a drive to explore their universe (although admittedly within the limitations of their physical capabilities). As an example, if properly supported and alert, neonates reach toward a visually captured object (Bower, Broughton, & Moore, 1970; von Hofsten, 1982). Although this behavior has been termed prereaching (Trevarthen, 1974) or prefunctional (von Hofsten, 1982), it is voluntary and has purposefulness not seen in more reflexive behaviors.
MOVEMENTS USED IN OBJECT EXPLORATION BY I NFANTS Humans are born with the drive to reach out and explore the physical world. Even as a neonate, the infant uses primitive motor skills to begin this process. Based on the observation of infants from 1 month to about 10 to 12 months of age, Karniol (1989) proposed 10 stages in the early object exploration of the infant
BOX 8-1
Ten Stages in the Development of Object Manipulation in Infancy
ONE TO THREE MONTHS Stage 1: Rotation: An object is moved by twists of the wrist. Stage 2: Translation: There are movements of the arm that change the location of an object by increasing or decreasing the distance from self. Stage 3: Vibration: There are repeated, rapid bending motions of the arm as the object is held. THREE TO FOUR MONTHS Stage 4: Bilateral Hold: The object is held passively in one hand as the other hand holds or does something else to another object. Stage 5: Two-handed Hold: A single object is held with both hands. Stage 6: Hand-to-Hand Transfer: An object held in one hand is transferred to the other. FIVE MONTHS Stage 7: There is coordinated action with single object: One hand holds the object stationary and the other hand does something to it (e.g., strokes a doll or pulls at the hair). SIX TO NINE MONTHS Stage 8: There is coordinated action with two objects: Manipulation of two objects, each held in a separate hand, such as hitting two blocks together. Stage 9: Deformations: The object is made to change shape, such as tearing paper or pressing a toy to make a sound. Stage 10: Instrumental Sequential Actions: There is the sequential use of two hands in obtaining a goal, as demonstrated when the infant lifts a cup to obtain a cube. Data from Kamiol R (1989). The role of manual manipulative stages in the infant’s acquisition of perceived control over objects. Developmental Review, 9:222–225.
(Box 8-1). Three of these stages—rotation, translation, and vibration—were related to the young infant less than 4 months old. If an object was placed in the hand of a 2- to 3-month-old infant, the earliest engagement Karniol noted was that the infant would rotate or twist the wrist, but only if the object happened to be visible to the infant. If the hand was not visible, the object was dropped. The next actions seen were translation movements, or a deliberate effort to change the location of an object by moving the arm toward or away from the body. Often this involved bringing an object to the mouth or was combined with rotation. Karniol believes that these movements assist the infant in combining changes in the retinal image of the object with proprioceptive feedback from the arm. The third method of engagement that Karniol observed in the very young
Object Manipulation in Infants and Children • 145 infant was a movement she called vibration. She defined this as rapid, periodic movements of an object by repeated bending of the arm. If the object produced noise, the motion might be maintained or be more vigorous. If the object did not make noise, it might be translated, rotated, and visually examined before being dropped. Consequently it appears that the very young infant will manipulate objects if they are placed in the hand, but this manipulation is limited to movements of the arm and wrist. As we will discuss later, grasp itself can also provide information about object properties to even very young infants. Young infants also may use their feet for exploration. Galloway and Thelen (2003) found that when infants about 3 to 4 months old were given an opportunity to contact a suspended toy with either their feet or their hands, the infants were able to make contact with their feet at about 12 weeks of age and with their hands at about 16 weeks of age. Reach is becoming functional at 4 months of age; the 4-month-old infant can also bring both hands together to engage the object at midline. This ability expands the action that can be taken on objects and is a necessary first stage of “complementary two-hand use” (Bruner, 1970). Midline behavior is facilitated by changes in the general control of the arm and the body itself. There is better balance in the trunk, as well as neck flexors and extensors, so the head is held in midline and the child can tuck the chin to better observe the hands. By 4 months the child can also lie on his or her back and bring the hands together up into the space above the body (Bly, 1994). This ability to bring the two hands together is used by the infant in exploring objects. At 3 to 4 months, Karniol (1989) adds bilateral hold and two-handed hold to the list of options available to the infant; that is, the infant can hold an object while the other hand does something else or hold the object using two hands. In a study of the object manipulation and exploration of 2-, 3-, 4-, and 5-month-old infants, Rochat (1989) saw an increase in mouthing in the 4to 5-month-old infants over the 2- to 3-month-old infants, a behavior he found significantly associated with two-handed grasp. Therefore two-hand support for an object may assist the infant’s attempts to mouth objects, increasing the likelihood that this form of exploration will occur (Figure 8-1). Once midline engagement of the hands is developed, manipulation also is assisted by allowing one hand to hold and the other to explore the surface of the object with the fingers. Rochat (1989) also saw an increase in this fingering behavior in his 4-month-old subjects. Further object exploration is possible around 5 to 6 months of age, when the infant is able to transfer an object hand to hand. This is an important comple-
Figure 8-1 Mouthing of objects is assisted once an infant is able to use two hands to support the object (4-month-old infant).
mentary two-hand use stage. Karniol (1989) indicated that, when this action is first seen, the infant often rotates the wrist and bends the arm with the object in one hand and then transfers it to the other hand and repeats the action. In recording the infant’s exploratory actions during a 90-second segment with a toy, Rochat (1989) found that the 5-month-old infants in his study transferred the toy a mean of three times, whereas the 2-, 3-, and 4-month-old infants transferred the toy a mean of less than once per trial. Therefore like Karniol’s infants, Rochat’s infants began to incorporate hand-tohand transfer into their exploratory play at about 5 months of age. By 6 months of age infants have a variety of actions at their disposal by which they can explore and manipulate objects. They can mouth, look, rotate, wave, bang, finger (run the fingers over the surface of an object), and transfer the object hand to hand. Nevertheless grasp at this stage is still dominated by a power grip. The thumb may be opposed to the fingers when picking up an object such as a block (Halverson, 1931), but when a smaller object is grasped, the fingers and thumb work together so the object is raked into the hand. By 9 to 10 months of age a major change occurs. Infants can now isolate the movements of the index finger and thumb from other movements of the hand and fingers. They can poke with the index finger and pick up a small object in a precision grip between the radial fingers and thumb (Folio & Fewell, 2000). When studying 6-, 9-, and 12-month-old infants, Ruff (1984) found an increase in fingering behavior in the older infants (running the fingers over the surface of an object), a function she felt was facilitated by the increased independence of the fingers and increased
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Figure 8-2 Older infants can hold a cube with the fingers acting independent of the palm. The object no longer needs to be pressed into the palm but can be held out on the finger surface (10-month-old infant).
coordination of the two hands. Grasp of an object, such as a cube, has also changed; the cube can now be held with the fingers acting independent of the palm, so the object no longer needs to be pressed against the palm but can be held out on the finger surface (Halverson, 1931) (Figure 8-2). The ability to move the object out onto the finger surface, the development of a precision grip, and the beginning of the differentiation of individual fingers are critical to the further development of skilled manipulation by the hand. Another important development during this period is the beginning of controlled release. As an example, it is also at about 9 to 10 months that infants can release a cube into a cup (Folio & Fewell, 2000). Therefore because infants’ exploratory actions become more refined as they gain better control over their motor abilities, the variety of actions that can be taken on an object increases. Infants use these motor skills to explore the properties of the objects they grasp. That is, infants’ actions with objects are not purely random but have the characteristics of true exploration.
EXPLORATORY NATURE OF I NFANT OBJECT MANIPULATION Although the neonate may be able to accomplish a primitive form of reach, he or she does not yet have voluntary control over the grasp of an object but will hold an object placed in the hand. For the young infant the mouth is also an instrument of grasp or exploration.
Rochat (1987) looked at the neonate’s use of the hand and mouth to explore or differentiate object properties. He addressed this question by looking at the reaction of neonates to a soft or rigid object placed in either the mouth or the hand. Newborn infants (49 to 96 hours of age) were presented with either a soft foam or rigid plastic tube, which was placed in their hand for grasp or in their mouth for sucking. The tubes were attached to a transducer, which was able to monitor the amount of pressure the infants applied to the two different objects. When grasped with the hand, the hard object was associated with significantly more squeezes than the soft object. When it was placed in the mouth, the reverse was seen. Obviously the infants were responding to differences in the flexibility of the object. The author suggests that the hand appears to be more concerned with the graspability of an object and the mouth with suckability. He also states that this “supports the idea of an early detection of what objects afford for functional action”; that is, the hand and mouth are tuned from the very beginning to actively explore an object’s functional properties. More recent studies also have found that the grasp of the neonate is not just a rigid reflex but rather a movement that allows the infant to gather information about object properties. Streri, Lhote, and Dutilleul (2000) placed either a cylinder or an elongated prism in the hands of neonates. After they had habituated to the object (defined as holding time that decreased to one third of the time on the first two trials or after nine trials), the infant was either given the same or the opposite object to hold. Holding time increased when the infant was presented with the novel object. It appeared that the infants were differentiating between the two shapes and demonstrating at least a primitive form of tactile discrimination. Neonates 3 days old can also differentiate between objects that are smooth or have a granular surface (Molina & Jouen, 1998, 2004). The infants in these studies tended to use more pressure when holding a smooth object and less pressure when holding a granular object. Molina and Jouen (2004) believe that neonates’ grip is an exploratory tool that can be used to process object properties. The object manipulation of the infant less than 4 months of age is necessarily limited because reach and grasp are still quite primitive. Yet if an object is placed in the infant’s hand or the infant happens to grasp an object once in contact with it, some attempts to explore the object’s characteristics appear to be present. Older infants have more physical skills at their disposal that are used to explore object properties. Steele and Pederson (1977) looked at the difference in manipulation with changes in object properties in 6-monthold infants. They measured the amount of visual fixation on the object, as well as the amount of manipulation.
Object Manipulation in Infants and Children • 147 Manipulation in this study was defined as any contact between the infant’s hand and the object. No attempt was made to further define the type of manipulation. Familiar objects the infant had previously manipulated and novel objects were used. The authors found an increase in looking and manipulating with novel more than familiar objects and also an increase in manipulation to changes in shape and texture but not to color. Of these two variables, texture elicited more manipulative behavior from the infants than changes in shape. The authors concluded, “the results indicate that an object that presents different tactile sensations is necesary to produce different manipulative behaviors.” Ruff (1984) also looked at how infants responded to different object characteristics. In this study, infants of 6, 9, and 12 months of age were presented with two sets of blocks that varied in color and pattern; more importantly, they also varied in surface texture and shape. Of interest was the observation that the infants tended to adjust their manipulative behavior to the different physical characteristics of the objects; that is, they mouthed and transferred the object more in the shape series and did more fingering in the texture series (e.g., blocks with bumps and depressions). In addition, with increasing familiarity with an object, these exploratory actions on the object decreased. This included looking, handling, rotating, transferring, and fingering. One behavior, banging the object, did not decrease over time. The author suggests that this activity may represent a play behavior unrelated to object exploration. This was also found by Ruff and co-workers (1992), who further suggested that certain types of mouthing might not be related to true object exploration.
OBJECT EXPLORATION BY THE MOUTH AND HAND In early infancy object exploration by both the mouth and hand is a major component in the infant’s interaction with objects, particularly the infant 7 months of age and younger. Ruff and co-workers (1992) indicated that, in their study, mouthing behavior peaked at about 7 months of age and comprised 27% of the time the infant was engaged with an object. This fell to 17% for 11-month-old infants. Ruff (1984) suggested that the decrease in mouthing might result from a better haptic system becoming available in the hand. Ruff and co-workers (1992) looked at the exploratory behavior of both the hands and the mouth in 5- to 11-month-old infants. They described what they called active mouthing and distinguished this from more general actions of objects in the mouth. Active mouthing was defined as movements of the object in the mouth by the hand (e.g., being turned in the
mouth) or when the mouth moved over the object. The authors found a significant association between active mouthing and then immediately looking at the object, but not other forms of object–mouth interaction (e.g., just holding the object in the mouth). After a bout of active mouthing the infant immediately paused to look at the object. They hypothesized that mouthing with looking might serve an exploratory or information-gathering function. To study this further, they presented infants with familiar and novel objects and noted the forms of exploration used in the two situations. They found that mouthing with looking and manual actions such as turning the object, transferring hand to hand, and fingering all declined as the infant became familiar with the object but returned when the infant was presented with a novel toy. Therefore they suggest that these actions are truly exploratory and a means of gathering information about objects. Other actions, such as mouthing without looking, banging, and waving, did not significantly decline in frequency as the infants became familiar with the object, and they indicate that these actions may serve some other function.
ROLE OF VISION IN I NFANT OBJECT MANIPULATION Up to this point we have discussed changes in the motor system that provide the infant with mechanisms by which object manipulation and exploration can happen. We have also indicated that even neonates appear to use the motor skills available to them to explore object characteristics. Also important to the object exploration of infants is consideration of the role vision plays in driving and supporting this behavior. Blind infants are significantly delayed in their object exploration when compared with sighted peers. Fraiberg (1968) indicated that totally blind infants do not spontaneously bring their hands to midline for mutual fingering, as seen in the 4-month-old sighted child. She argued “that there is good reason to believe that the mutual fingering games and the organization of the hands at midline are largely facilitated by vision and that the tactile engagement of the fingers requires simultaneous visual experience to insure its pleasurable repetition.” She also indicated that the hands of the totally blind infant do not explore objects, but serve primarily to bring the object to the mouth. Consequently it appears that, for the normally sighted infant, vision is an important motivator that leads the hand into space and serves to facilitate grasp and manipulation. Even in neonates manual activity appears to be directed by visual information. Molina and Jouen (2001) presented 3- to 5-day-old neonates with one of two objects. One object was smooth and
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the other granular (same objects used in the studies mentioned previously). In a pretest period one of the objects was placed in the infant’s hand without the infant being able to see the object. The time until the object was dropped and the amount of pressure exerted on the object were measured. After this pretest period the object was placed back in the infant’s hand at the same time a smooth or granular visual object was presented on the table in front of the infant. Therefore the child was holding one object and looking at another object that was either the same or a different texture than the one being held. The holding time and pressure on the held object were measured again. The visual object was then removed and the holding time and pressure on the object that remained in the hand were measured. The authors found that the holding time when the texture of the held object and the visual object matched increased but holding time remained the same when the visual and tactile objects were mismatched. Molina and Jouen (2001) feel the results indicate that the infant is comparing the held object with the visual object. If the infant finds differences between the tactile and visual object, the process of comparison is stopped. That is, holding time decreases because the “problem” the child was given is solved. Alternately, as long as no differences are observed between the tactile and visual object, the process of comparison is ongoing and exploration time is increased. Therefore the authors feel that vision and touch are interconnected even at birth and that neonates can make some comparisons across these two modalities. The role of vision also can be seen in older infants. As indicated, Karniol (1989) found that when a 2month-old infant grasped an object, he or she would rotate it but only if the hand could be seen. If the hand was out of visual regard, the object would be dropped. In his study of 2- to 5-month-old infants, Rochat (1989) looked at what infants did first with an object. Did they immediately bring it to the mouth or did they first bring it to the eyes to look at it? (The infants were all seated in slightly reclining infant seats.) He found that at 2 to 3 months more than two thirds of the infants first brought the object to the mouth. At 4 to 5 months the majority of the infants first brought the object into the field of vision for inspection. This was particularly true of the 5-month-old infants, in whom visual exploration was used first in 90% of the sample. Rochat (1989) also indicated that fingering of an object by infants might be linked to vision. In one study using 2-, 3-, 4-, and 5-month-old infants, the author found a significant interaction between fingering and looking. To test this interaction further, he studied a different set of 3-, 4-, and 5-month-old infants as they manipulated objects in dark and light situations. The dark situation was accomplished using an infrared light
and a video camera sensitive to this light. He found that fingering was dramatically decreased in the dark situation, whereas the incidence of mouthing and handto-hand transfer remained the same in the two experimental conditions. The author indicated that early fingering appears to be linked to vision and depends on this modality. Alternately, mouthing appears to be independent of vision, and in this study early hand-tohand transfer also did not seem to depend on vision. Therefore it appears that, at least in younger infants, vision is an integral part of the process of grasp and manipulation, and in fact may be the early motivator for object exploration and drive some of the more refined manipulative actions, such as fingering of an object.
HANDLING M ULTIPLE OBJECTS Effective object manipulation also requires that the infant solve the problems of how to deal with more than one object at a time. Bruner (1970) attempted to look at what he called “taking possession of objects” by presenting infants with a small toy and then presenting a second toy to the same hand. If the infant did not make an attempt to secure the second toy, it was then held at midline. After two toys were grasped, the infant was handed a third and fourth toy and the child’s solution to this multiple object problem was observed. Bruner found that 4- to 5-month-old infants had difficulty managing two objects. Often, as the infant’s attention was attracted to the second toy, the held toy was dropped. The 6- to 8-month-old infants were able to solve the two-toy problem by transferring the initial toy to the other hand and then grasping the second toy. Solving the problem of three objects required a different strategy that was not seen until 9 to 11 months; that is, when offered the third object, the older infants “stored” one of the objects he or she had been holding on the table or lap. But half the infants of this age then retrieved the stored object immediately. They did not appear to be able to inhibit the drive to pick up what they saw or could not delay this process. By 12 months the infants had the solution of this problem well “in hand.” They not only transferred the first object to the other hand in anticipation of receiving the second object, but also anticipated the third and fourth by storing the toys in hand in the lap or the arm of the chair. By 15 to 17 months the infants also stored by handing objects to the parent or examiner. Therefore by 12 months and older, infants have learned to deal with several items at one time.
SUMMARY AND THERAPEUTIC I MPLICATIONS As infants gain control over the movements of their arms and hands, they also increase the options available
Object Manipulation in Infants and Children • 149 to them for object exploration. In the very young infant objects are fixed in the hand, and exploration is limited to a power grip and movements of the arm and wrist. An important expansion of the actions available to infants comes when they can bring both hands together and eventually transfer an object from one hand to the other. The infant can now wave, bang, mouth, transfer, rotate, and run fingers over an object’s surface. The ability to manage more than one object at a time is also an important aspect of object interaction, and infants appear to gradually accomplish this skill over the first 12 months of life. During this period infants also develop two other extremely important skills: Control over voluntary release or placement of an object, and the ability to use a precision or refined pincer grip. This latter skill is critical to the further development of object manipulation by the hand. From a therapeutic point of view, one should note that changes in object properties seem to elicit different manipulative behaviors from infants. As an example, changes in shape appear to generate more transferring and rotation activities, and changes in texture more fingering and possibly an increase in the duration of manipulation (Figure 8-3). Often parents and others who interact with infants see the infant’s mouthing, turning, and handling of objects as random motions. As indicated, however, at least some of these movements appear to be meaningful attempts to explore object properties. This is important information to consider when evaluating and planning programs for a child. Pointing out to parents or caregivers how the infant changes manipulative strategies with changes in object properties can help them appreciate the infant’s competencies and the importance of these actions to the infant’s learning. Providing the infant with a variety of objects that differ in shape and texture may well facilitate this process. In observing infants, it is also important to note when they do not show the variety of exploratory behaviors appropriate for their age. As indicated, waving, banging, and some forms of mouthing may not serve the same exploratory functions as activities such as transferring hand to hand, fingering, rotating, and active mouthing. Ruff and co-workers (1984) state that “The infant who does not finger, rotate, and transfer objects very much has less opportunity to learn about object properties. We can speculate that the less infants learn about object properties the less they will engage in categorization of objects. Any deficit in categorization should affect early language development. In this way it is possible for manipulative exploration of objects to contribute directly to an infant’s cognitive development” (p. 1173).
Several studies (Church et al., 1993; Goyen & Lui, 2002; Ross, 1985; Ross, Lipper, & Auld, 1986; ThunHohenstein et al., 1991) have found preterm infants to
A
B Figure 8-3 Changes in an object’s texture and surface characteristics may increase higher-level manipulation such as fingering. This figure shows two infants who are approximately 9 months old using finger movements to explore (A) a yarn ball, or (B) bells attached to a toy.
score lower than term infants on eye–hand and fine motor items of developmental tests. Kopp (1976) found preterm infants to differ significantly from fullterm infants on the duration of exploratory activity. In another study this same author (1974) found a greater percentage of preterm infants (age corrected for prematurity) to be clumsy in object manipulation when compared with term infants (70% of the preterm infants and 19% of the term infants). The clumsy infants also were noted to spend less time manually exploring objects and more time in visual exploration. Ruff and co-workers (1984) also studied the manipulative abilities of preterm and term infants. They divided the preterm infants into high- and low-risk groups depending on the infants’ early medical history. They then compared these two groups to a group of full-
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term infants (preterm infants’ age corrected for prematurity). They found a significant decrease in the incidence and amount of fingering, transfer, and rotation of objects in the high-risk group compared with the two other infant groups. Apparently for some infants, the delay in fine motor skills is long lasting. Goyen and Lui (2002) followed 54 high-risk infants (<29 weeks’ gestation or <1000 g) until 5 years of age. At 5 years, 64% of the children scored below 1 standard deviation on the Peabody Developmental Fine Motor Scales. The quality of an infant’s object interaction can provide important observational information and assist in providing caregivers with suggestions for an infant’s continued development. Infants learn about their physical world through their manipulative actions. These activities offer the infant an opportunity to experience a sense of success and mastery and may provide experiences on which later cognitive strategies can be based. These experiences may not be readily available to the physically handicapped infant, and this child needs to be assisted through proper positioning and the selection of appropriate toys. Assistance has been shown to increase object engagement in typically developing infants. Lobo, Galloway, and Savelsbergh (2004) found an increase in the number of contacts made to a toy by 2- to 3-month-old infants after 2 weeks of increased experience with toys. In this study the infants either were manually assisted in contacting an object at midline or the limb was tethered to an overhead toy with a ribbon so that limb movements moved the suspended toy. In another study, Needham, Barrett, and Peterman (2002) studied 3-month-old infants after an enrichment experience that consisted of 12 to 14 parent-led play sessions, each about 10 minutes in length. During the sessions the infants wore mittens with Velcro covering the palmar surface. They were then presented with small toys that had the alternate side of a Velcro strip attached to the toy. The study design also included a group of infants whose parents were instructed to follow their normal daily routine during the 2 weeks of the study. After the 2 weeks, the infants in the experimental condition produced more intentional swats at objects than the infants in the control condition. They also showed greater switching between visual and oral exploration. The authors conclude, “Experiences acting on objects may be a critical factor in increasing infants’ engagement in objects and their object exploration skills. Not only do infants explore objects more after this experience, they employ more sophisticated object exploration strategies that involve more coordination between visual and oral exploration.” Object exploration is an important part of development, even for the very youngest infants. The more we
know about how typical infants interact with the objects in their environment, the more effective we are in encouraging this area of development in infants for whom this is felt to be an area of concern.
OBJECT MANIPULATION DURING THE TODDLER YEARS Compared with those of the infant, the manipulative skills of the toddler show great strides in development. Unfortunately, we know this more from intuition than actual research. Toddlers can do more than “grasp” an object; they begin to manipulate the object in their fingers and hands. Release of an object also has improved, and these two skills allow the child to interact effectively with smaller objects. It is also at this age that children start to demonstrate complementary twohand use, greatly expanding their manipulative abilities. Each of these areas is explored.
BEGINNING OF I N-HAND MANIPULATION In discussing the fine motor abilities of the 12-monthold child, Gesell and co-workers (1940) stated that the child’s “prehensory patterns are approaching adult facility … fine prehension is deft and direct.” That is, the child has a neat pincer grasp and can use it with skill. As indicated, this is an important achievement for the child, but these prehensory patterns must be changed to manipulatory patterns for true hand skill to develop. As an example, 12-month-old infants can pick up a small object such as a Cheerio very well, but if provided with several Cheerios in the hand, their manipulative skills are challenged. Young children generally solve this problem by bringing the entire hand to the mouth rather than moving the object within the hand. Therefore one of the tasks in the next few years is to take the “deft and direct” prehension patterns they have learned and develop the capacity to manipulate objects in the fingers and in the hand. Exner (1990, 1992, 2001; see also Chapter 12) has called this ability in-hand manipulation or the adjustment of an object in the hand after grasp. The purpose of these adjustments is to allow more efficient placement of the object in the hand for use or voluntary release. Three components of this skill have been defined. One is the ability to move an object from the fingers to the palm or the palm to the fingers (e.g., picking up a coin and placing it in the hand and then moving the coin from the hand to the fingers for placement in a bank or purse). Exner refers to these as translation movements. Another component is the ability to rotate the object in the pads of the fingers,
Object Manipulation in Infants and Children • 151 either through simple rotation, in which the object is rolled or turned in the fingers, or more complex rotation movements. In more complex rotation movements the object is generally rotated at least 180º, and the movement requires independent action of the fingers and thumb. The third component is shift, or the movement of an object in a linear direction on the finger surface. The thumb often performs most of this movement with reciprocal movements of the radial fingers such as moving a pencil after it has been grasped so the fingers are closer to the point (Exner, 1990). In addition, these activities can also be accomplished while another object is stabilized in the hand. An example of a palm-to-finger movement with stabilization is when several small objects are held in the hand and one of them is moved to the fingers for placement, such as when one of several Cheerios is moved from the palm to the fingers for placement in the mouth. Children in the toddler years are not yet adept at all components of in-hand manipulation. In her original pilot study, Exner (1990) looked at the in-hand manipulation skills of 90 children 18 months to 6 years 11 months old. The developmental trend in these skills indicated that moving an object like a small peg from the fingers to the palm for storage, then moving it back out to the fingers, and simple rotation were three of the easiest tasks and were accomplished by at least half of the 18-month to 2-year-old children in her study. Other tasks, such as the complex rotation of a pen in the fingers so the point is in a position for use, were more difficult and not accomplished until the preschool years. Exner (1990) indicated that skills that do not involve simultaneous stabilization of materials during in-hand manipulation activities are easier than those in which the child must control both sides of the hand (ulnar side to hold and radial side to manipulate). Exner (1992) also indicated that the amount of individual finger movements necessary for a task may make one component of in-hand manipulation more difficult than another; that is, the ability to move an object such as a peg from the fingers to the palm is a relatively easy task because the fingers tend to work as a unit. However, rotating a pen in the fingers for use requires the sequencing of individual movements among the radial fingers and the thumb. Although the 12-month-old child has the ability to isolate the index finger and can use the index finger or radial fingers and thumb to pick up a small object, there is reason to believe that further isolation of finger movements is still difficult for the child under 3 years of age. As an example, Stutsman (1948) looked at the ability of young children to make a fist and wiggle the thumb without moving the fingers. She states that this task “appears rather suddenly at 33 months.” Gesell and co-workers (1940) also talked about the ability to
wiggle the thumb (or voluntarily isolate the movements of the thumb) as being a skill observed in 2-year-old children. The ability to move the fingers individually seems to come later. When Stutsman (1948) asked young children to oppose each finger to the thumb, she found that this was possible for only three of the children she observed who were between 30 and 36 months of age. By 36 to 41 months, 35% of the children accomplished the task, but it was not until 42 to 47 months that 50% of the children were successful. It appears that isolated movements of individual fingers are difficult for children 3 years of age and younger, and this may be a major deterrent to the ability to accomplish deft and direct manipulatory patterns of objects in the fingers. Another factor that may limit the toddler’s in-hand manipulation skills is the force of the grip used to hold an object. When the grip strength was measured as children and adults picked up a small object between the thumb and index finger, children were observed to use greater grip force than adults (Forssberg et al., 1991; see also Chapter 3). This was particularly true for children 5 years or younger. When the steps necessary to prepare to lift a small object also were carefully measured with instruments sensitive to changes not observable to the eye, it was found that it took longer for young children to prepare to lift the object. Children 8 months (the youngest group of infants studied) to 18 months old demonstrated a significantly longer time from when the lead finger or thumb touched the block to when the second finger or thumb arrived. Small children also were noted to contact the object several times before a stable grip was established, and they also had a tendency to push down as they were gripping. Forssberg et al. (1991) indicated that this preparatory stage was three times longer in infants under 10 months old and about twice as long in children less than 3 years old. Therefore if young children have difficulty isolating finger movements, are slow in preparing for a grip (at a micro level), and tend to grip objects harder in their fingers than adults, then in-hand manipulation skills that require the grasp and release of an object and the coordination of these movements among different fingers are quite difficult or impossible. This also is true of older children with deficits or marked delays in these areas. As an example, fasteners on clothes, particularly buttons, require manipulation skills by the fingers. For many children under 3 years of age, this is a difficult task. Another task that requires isolated movements of the fingers is the ability to move a pencil or writing implement in a dynamic tripod grip. This is also difficult for many children under 3 years of age (Rosenbloom & Horton, 1971; Saida & Miyashita, 1979; Schneck & Henderson, 1990). Despite these limitations, the toddler is beginning to experiment with simple in-hand
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manipulation tasks such as picking up and storing several objects in the hand. These functions improve as the child gains more control over the movement of individual fingers and refines the force of grip.
CONTROL OVER OBJECT RELEASE The child 12 months to 2 years of age is gaining control over the release of objects. This is an area that has not been widely studied, even though Gesell and coworkers (1940) state that release is “one of the most difficult prehensile activities to master in early life.” These authors point out that it is the inability to release a cube properly that often causes the infant to fail when attempting to build a two-block tower. Efficient object release requires both the regulation of grip force with the timing of the placement of the object so the object is not “dropped” but precisely placed (Eliasson & Gordon, 2000). At 2 years of age, the child can build a tower of several blocks, but may press rather than place the block, often with enough force that the structure falls (Gesell et al., 1940). Gesell and co-workers (1940) also note that, even at 3 years of age, the child may still have difficulty with release on more delicate tasks. For instance, the child may pull the lace out when the hand is moved away while lacing shoes. Controlled release is an important component of object manipulation. In many in-hand manipulation tasks the object is grasped and then repositioned by delicate grasp–release movements of the fingers. The development of this ability, particularly the ability to release without the need to press down or use a supporting surface and to remove the fingers from the object surface with correct timing, is a valuable area for future research.
COMPLEMENTARY TWO-HAND USE Complementary two-hand use is an important skill that develops between 12 months and 2 years of age (Bruner, 1970). As indicated in the previous section, the infant’s ability to use two hands in the manipulation of an object greatly expands the exploratory options available. Nevertheless, being able to hold an object in each hand, or even the ability to hold an object in one hand while acting on this object or manipulating another, does not take advantage of the potential skill achieved when both hands are active at the same time. This requires that the child be able to program or motor plan different but complementary actions with the two hands. This ability is more than just programming a holding function for one hand and a doing function for the other. It involves the monitoring of active movements of both hands at the same time. There is reason to suspect that this skill is not present until 2 years of age. To look at the development of
complementary two-hand use, we now step back and briefly look at the younger infant to observe the transition to higher-level activities. Bruner (1970) studied the early acquisition of this skill in infants 6 to 17 months of age. He presented the infants with a box that required them to hold open a sliding, transparent lid to obtain a toy. Bruner found that the 6- to 8-month-old infants in his study tended to just bang or claw at the lid itself. In fact, this activity often appeared to distract the infant from the toy, and banging became the main activity of interest. He indicated that this behavior also was common in 9- to 11-month-old infants. In addition, another common behavior of infants of this age was to open and close the lid, becoming distracted by this activity and not attempting to retrieve the toy. Another behavior that was seen in these younger infants was the opening of the lid with one hand and then slipping the same hand into the box with the other hand not participating at all. At 12 to 14 months, the infants added another approach to the solution of the problem; to raise the lid with one or two hands and go after the toy with the free hand but to let go of the lid during the retrieval attempt. Even at 17 months, which was the oldest group of infants studied, the activity was not yet well mastered. Ramsay and Weber (1986) used a similar task in looking at this skill in 12- and 13-month-old infants compared with 17- and 18-month-olds. They found their infants to be a bit more competent than Bruner’s (1970), which in part may have been related to differences in the testing apparatus. Ramsay and Weber also had a box with a transparent lid, but this lid was hinged and lifted rather than pushed open. Another difference was that the transparent lid in Ramsay and Weber’s study was furnished with a white knob. This may have provided the children with a clue as to how to solve the problem. Ramsay and Weber state that in their study use of only one hand was rare and seen only in the younger age group. The most common method of approach was to lift and hold the lid with one hand and to retrieve the toy with the other hand. They found this approach to be used an average of 50% of the time in the 12- to 13-month-old children and 78% of the time in the 17- to 19-month-old group. The younger children also used a strategy in which both hands opened the lid, and then one hand held as the other hand retrieved the toy. This was seen an average of 37% of the time in the younger group and only 12% of the time in the older infants. Another strategy that was used almost equally by both groups of infants was to lift the lid with one hand, then transfer the hold of the lid to the free hand, and retrieve the toy with the hand that originally opened the lid (used 13% of the time by the younger infants and 10% of the time by the older group).
Object Manipulation in Infants and Children • 153 Stutsman (1948) has commented on this function in children. She states that the “inability to perform different movements with the two hands at the same time seems to be characteristic of the child under 36 months of age.” One of the tasks she presented to young children was to give them a long string attached to a toy that was lying on the floor. The child was instructed to pull in the string to attempt to get the toy. Unsuccessful attempts included walking over to pick up the toy or only yanking the arm back to partially move the toy forward. The problem was correctly solved only when the child managed to pull in the string hand over hand to obtain the toy. She found that 90% of the 30to 35-month-old children in the normative sample were able to solve the problem, and 60% of the 24- to 29-month olds, but only 22% of the 18- to 23-montholds. Stutsman (1948) also lists scissor cutting as a striking measure of bilateral hand use (Figure 8-4, A). She suggests this skill is difficult for the child 24 to 29 months of age because he or she cannot yet sufficiently differentiate movement of the two hands. Another task that requires complementary use of two hands is bead stringing (Figure 8-4, B). Often young children who are unsuccessful in this task seem to have an idea of how to proceed but have difficulty
A
B Figure 8-4 (A) Scissor cutting, and (B) bead stringing are two of the tasks that readily demonstrate a young child’s ability to use both hands together in a task.
with the complementary two-hand aspect of the task. They place the string correctly into the bead but then do not seem to know how to transfer the activity between the two hands to complete the task. Almost all studies place the successful accomplishment of bead stringing at 2 years of age (DuBose & Langley, 1977; Folio & Fewell, 2000; Gesell et al., 1940). As an example, in the Peabody Developmental Motor Scales (Folio & Fewell, 1983), the ability of young children to string three beads is examined. The authors found that this task could be accomplished by only 16% of the 18to 23-month-old children in the normative sample, but by 70% of the 24- to 29-month-old children, which represents a significant change in behavior over a relatively short time. It appears that something happens that allows this task to be successfully completed. It is probable that a major factor in this success is the emergence of complementary two-hand use.
SUMMARY AND THERAPEUTIC I MPLICATIONS The child at 12 months to 2 years of age has made marked strides in the development of the control necessary for refined object manipulation by the hand when compared with the infant. The child is beginning to develop in-hand manipulation skills, which are facilitated as the child gains increasing ability to isolate the movements of individual fingers and when the force of grasp is better controlled. The child also gains marked control over the release of objects when compared with the infant, and the child now uses both hands together in a complementary fashion. This is also a time when complementary two-hand use is developing, and the child may enjoy the opportunity to practice these skills. Placing items in a purse or bag necessitates interaction between the two hands, because the activity often is not successful unless the holding hand is also active during the process. Bilateral hand skills also make dressing oneself possible. Children can now coordinate the use of two hands to pull up their pants or put on a sock. Object size needs to be considered. Exner (1990) found that the manipulative abilities of small children were affected by the size of the objects presented. She found that, in general, tiny (1⁄2-inch peg) or medium (1-inch cube) objects were more difficult to handle than an object such as a key. Connolly (1973) also found differences in children’s grip patterns based on differences in object size. Newell et al. (1989) looked specifically at the effect of object size in relation to hand size in children 3 years 3 months to 5 years 4 months when compared with adults. The subjects were asked to pick up boxes of varying size (0.08 to 24.2 cm) and place them in another slightly larger box. The authors found that young children and adults predominantly
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use the same grip pattern when the object is scaled to the size of the hand. Children at this age enjoy picking up and manipulating small items and they appreciate the opportunity to explore their ability to pick up and hold several small objects in their hand as long as care is taken that the objects cannot be swallowed (e.g., a flat plastic disc that is 11⁄2 inches in diameter or larger allows the small child to practice refined manipulation movements, and yet the object cannot be swallowed if placed in the mouth). Besides having large dolls or trucks available to play with, the child also can be furnished with small trucks and dolls that require more delicate movements of the hand. Therefore object size should be considered when planning activities for small children.
OBJECT MANIPULATION IN THE PRESCHOOL AND EARLY CHILDHOOD YEARS Age 3 through 6 years appears to be a time when the child is gaining control over the intrinsic movements of the hand. One of the major changes seen during this period is the continued emergence of in-hand manipulation skills. This ability greatly expands the activities the child can accomplish. For example, at 3 to 7 years old the child learns to deal with the fasteners on clothes, and cuts, pastes, and manipulates writing instruments. These tasks require both cooperation between the two hands and the ability to manipulate objects in the fingers and hand.
STUDIES OF I N-HAND MANIPULATION Buttoning is one of the representative manipulative skills that has been studied during this age period. Stutsman (1948) indicated that no child in her normative sample who was under 23 months of age was able to manage the button on a one-button strip, and only 9% of 24- and 29-month-olds successfully completed this task. This is not surprising considering the difficulty children of this age have in differentiating the movements of individual fingers, as well as efficient use of the two hands together. She found a major change in the ability of 30- to 35-month-old children. In this age group 72% of the sample was successful (Figure 8-5). Despite the 30- to 35-month-old children’s ability to perform the task, their efficiency or speed was markedly different from that of older children. For example, Stutsman found that it took an average of 170 seconds for the children in her 30- to 35-month-old sample to button two buttons, whereas 12 months later, at 42 to
Figure 8-5 Buttoning is a task that requires both efficient use of the two hands together and the ability to differentiate the movements of individual fingers. It is a complex manipulative skill that is not accomplished well until the preschool years.
47 months of age, the children completed the task in 34 seconds. Folio and Fewell (1983) found similar results when they asked children to button and unbutton one button in 20 seconds. Only 2% of the normative sample at 30 to 35 months could accomplish the task, whereas at 48 to 59 months 65% of the children were successful. Therefore, despite the ability of many 21⁄2-year-old children to accomplish buttoning, the speed with which the activity is performed is so slow as to preclude it from being functional. Are the younger children slower because the basic movements themselves are not as efficient, or are they using less efficient methods than older children? Pehoski, Henderson, and Tickle-Degnen (1997) looked at this question using an in-hand manipulation task. They asked 153 children between the ages of 3 years and 6 years 11 months to turn over 10 small pegs in a pegboard using only one hand (a complex rotation task). A group of adult subjects also was presented this task to establish a standard against which the children’s performance could be judged. All the children sampled were able to accomplish the task, but the time they took for completion and the methods they used to perform this activity differed among the age groups. The time for completion decreased with age, as did the variability in time scores within an age group, but even at 6 years 11 months the children were significantly slower than the adults. Of the age groups of children tested, the 3-year-olds were by far the slowest group and differed significantly from the other age groups. Perhaps of more interest was the finding that the methods the children used to accomplish this task differed. In the sample of normal adults, Pehoski and co-workers (1997) found that all the subjects used the same method to perform this task. Each of the adults picked up the 10 pegs and rotated them using a series of individual movements of the two radial fingers and
Object Manipulation in Infants and Children • 155
A
C
B
Figure 8-6 In a study of in-hand manipulation in young children, the children were asked to hold a dowel in their nonpreferred hand to encourage activity in the dominant or preferred hand as they turned over small pegs in a peg board. Three methods were used to accomplish this task: A, the method used by adults in which the pegs were rotated in the fingers; B, use of an external surface to support the peg as it was rotated (this was done most often against the child’s chest); and C, rotating the arm, and thereby excluding or simplifying the need for individual finger movements. The adult method increased in use with age (see Fig. 8-7).
the thumb. The methods used by the sample of children were more varied, and often the children mixed the use of more than one method in the repetitions of this task. Many of the children were able to demonstrate use of the adult method (Figure 8-6, A), but they also used two other approaches when solving this problem. One was to use an external surface against which the peg was turned, such as holding the peg against the chest as it was rotated (Figure 8-6, B). Inadvertent use of the other hand also was considered as using an external surface. (The children were instructed to hold a vertical post with their nonpreferred hand in order to encourage in-hand manipulation by one hand alone.) The other method was to rotate the arm before picking up the peg so that the peg was turned through the derotation action of the arm, thereby excluding or simplifying the need for individual finger movements (Figure 8-6, C). Use of the adult method increased with age, although even at 6 years this method was used only 80% of the time.
Of interest was the marked change to an adult method seen in 48- to 53-month-old children. The 3-year-olds in the sample relied heavily on the use of an external surface when turning the peg. This method was used an average of 40% to 50% of the time by the two youngest age groups. By 48 to 53 months this method had fallen to 25%, and the predominant method used was that of the adults (used 70% of the time). That is, by 4 years of age the children were rotating the peg in the fingers and used this method as the predominant solution to the problem (Fig. 8-7).
ROLE OF VARIABILITY IN MOTOR SKILL DEVELOPMENT Variability in the methods or grasps used when developing a new motor skill is a common finding in children. It has been described in studies of infant reach (Thelen et al., 1993), the placement of pegs in a hole by 12-month-olds (Moss & Hogg, 1983), the emergence
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100.0 90.0 80.0 70.0 60.0 50.0 40.0 30.0 20.0 10.0 0.0 3.0
FACTORS CONTRIBUTING TO THE I MPROVEMENT OF I N-HAND MANIPULATION SKILLS
3.6
4.0
4.6
5.0
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6.6 Adult
Age Adult method
Internal rotation
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Figure 8-7 Percentage of times each of three methods was used when attempting a simple rotation task by children 3.0 to 6.6 years of age. (From Pehoski C, Henderson A, Tickle-Degnen L [1997]. In-hand manipulation in young children: rotation of an object in the fingers. American Journal of Occupational Therapy, 51:544–552.)
of self-feeding in toddlers (Connolly & Dalgleish, 1989), and the use of writing implements in 3- and 5-year-old children (Greer & Lockman, 1998). The performance of adults on these same tasks is much more stable. A dynamic systems approach to development indicates that infants and children initially explore different ways of accomplishing a task and that these trials are based on the intrinsic dynamics of a particular child (Thelen & Smith, 1994). These dynamics might include such things as muscle tone, body dimensions, and temperament. As children encounter their environment and explore different forms of an action for a given task, they eventually settle on one form that is most effective and efficient for them (Greer & Lockman, 1998; Thelen & Smith, 1994). In this dynamic systems theory of development, variability in performance is viewed as a sign that the system is in transition and working toward a more stable performance. Although the goal may be the same for each child (e.g., to hold a spoon in a manner that allows food to be brought efficiently to the mouth, hold a pen to make a specific mark on a paper, or turn a peg over in the fingers), the various methods the child uses as he or she learns these skills depends on individual intrinsic dynamics. Therefore variability is seen as a developmental process that includes both physical change and experience. Children who are having difficulty with this process and are slow to develop a stable performance may need more time or experience practicing a task. They also may benefit from an attempt to analyze the intrinsic factors that may be limiting them so that changes or adaptations can be made to the implements or methods used.
What are some of the physical aspects that change to allow an increase in speed and a more consistent, adult method of performance? The adult method of turning over a peg using only one hand requires the differentiation and change in performance between the two radial fingers and the thumb. As discussed, the ability to differentiate the movements of the individual fingers (e.g., the ability to sequentially oppose the fingers to the thumb; Stutsman, 1948) seems to appear at about 42 to 47 months of age. Once present, there is a gradual increase in the speed of these movements. As an example, the Peabody Developmental Fine Motor Scales (Folio & Fewell, 1983) looks at the ability of children to oppose each finger to the thumb within 5 seconds. It was found that this task could be accomplished by only 22% of the 42- to 47-month-old children, but 72% of the 48- to 59-month-old children were successful. The ability to isolate individual fingers of the hand and perform this activity with speed appears to be a requisite skill for efficient in-hand manipulation activities and may be one of the reasons children 4 years of age and older are better at in-hand manipulation skills than are children 3 years old or younger. Manipulating an object such as a peg in the fingers, rotating a pencil so the tip is in the correct position to write, and turning a small bead in the fingers to orient the hole for stringing all require a grip that is firm enough to keep the object from being dropped but light enough to allow the object to be moved. In the study by Forssberg and co-workers (1991), children were noted to use significantly greater grip force than adults when picking up a small object. In adults the force of the grip is matched to the properties of an object (e.g., its weight and frictional qualities), and determining this force is related to tactile feedback from the hand (Westling & Johansson, 1984). Adults use just enough force to provide a small margin of safety so the object does not slip out of the fingers. If the adult’s fingers are anesthetized, eliminating the tactile feedback that monitors the frictional conditions between the object and the fingers, the ability to adjust the grip force is compromised. Therefore tactile feedback is necessary for the successful accomplishment of this skill. It is also interesting to note that Westling and Johansson (1984) found that the adults in their study with the greatest manual dexterity were also those who employed the smallest safety margins. Evans, Harrison, and Stephens (1990) have looked at the maturation of cutaneous reflexes in children. To do this they stimulated the cutaneous nerve of the
Object Manipulation in Infants and Children • 157 index finger and monitored the EMG response while the first dorsal interosseous muscle was actively contracting. The authors did not observe a full adultlike EMG response until the early teen years. As an example, the adult EMG response to digital nerve stimulation has three components: an initial increase in muscle electrical activity, followed by a decrease, and finally a second, prominent increase. The last of these components, called the E2 component, is felt to require the integrity of the dorsal columns (tract carrying discriminative somatosensory information to the cortex). In the Evans and co-workers (1990) study, the E2 component was not seen until 4 years of age, and then there was a gradual increase in the number of children who demonstrated this aspect of the response until 12 years of age, when all children exhibited an E2 response. Of further interest was the finding that children who did not demonstrate an E2 component were more likely to perform poorly on a test of rapid finger movements; therefore the appearance of this component of the cutaneous reflex response may be implicated in the speed of finger movements.
SUMMARY AND THERAPEUTIC I MPLICATIONS Children between the ages of 3 and 6 years are making rapid improvement in their ability to manipulate objects in the fingers and hand. This is still a difficult task for many 3-year-old children, and an activity such as buttoning is just beginning to be done with enough speed to make the task functional. Other activities, such as rotating a small object in the fingers, is still difficult for the 3-year-old, and the child is likely to substitute another method for the movements of the fingers (e.g., rotating the object against an external surface). The fourth year of age may be a time of marked change in these abilities, particularly the complex rotation of an object in the fingers. Pehoski and co-workers (1997) found that children at this age tend to switch from using an external surface when rotating a small peg to accomplishing the task with the fingers. Five- and sixyear-old children continue to show improvement in these skills, although this improvement is not as marked (e.g., the difference in improvement among the 4-, 5-, and 6-year-old subjects is not statistically significant). The fourth to fifth year of age also is the time when children are switching their pencil grip to a dynamic tripod, or a grip that incorporates small, intrinsic movement of the fingers (Rosenbloom & Horton, 1971; Saida & Myashita, 1979; Schneck & Henderson, 1990). Of interest is that several other physical functions also appear to be changing around 4 to 5 years of age. As an example, Forssberg and co-workers (1991) found that after 5 years there was no significant difference in
the grip force between a population of adults and children when the subjects were asked to pick up a small object between the index finger and thumb. As indicated, the regulation of the grip force rate on this task has been linked to tactile mechanisms. Evans and co-workers (1990) found that an important component of the cutaneous reflex is not present until 4 years of age and that the appearance of this component may be linked to the speed of sequential finger movements. The strength of the grip force and the ability to rapidly sequence the movements of the fingers are important components in the manipulation of an object in the fingers or the hand. Vision can guide the hand to the target, but tactile mechanisms guide the object in the hand. Nature may well have a rule that says, “Use whatever mechanisms you can to manipulate an object, but whatever you do, don’t drop it!” This rule is ensured by tactile mechanisms that detect even minor slippage of a hand-held object and tell the motor system to increase or adjust the grip (Johansson & Westling, 1984). If these mechanisms are immature, generally increasing the grip force or holding an object more tightly is one way to compensate for this skill. In Pehoski and co-workers’ study (1997), when children were asked to rotate a peg and replace it in the board, dropping the peg was not a common finding. No child dropped more than one of the 10 pegs, and approximately half the children dropped no pegs at all. When working with children, a tendency for objects to be dropped from the fingers should be noted. When this is felt to be excessive, one possible area to consider is the integrity of tactile motor mechanisms. Another point to note when evaluating children is that most tests for children in the preschool and early childhood years do not include items that assess inhand manipulation skills. Therefore the evaluator may wish to add tasks of this nature, particularly for the child who is 4 years of age and older, so these skills can be observed. As an example, first-grade children’s inhand manipulation skills are one of the factors that differentiate good from poor handwriting (Cornhill & Case-Smith, 1996); and the speed of rotation of small pegs in a peg board in preschool children has been shown to significantly correlate with a test of self-care (Case-Smith, 1996).
OBJECT MANIPULATION IN OLDER CHILDREN Information about the object manipulation of older children is limited. We do know that the speed of movement and a decrease in variability of movement is characteristic of older children. Finger movements get
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faster from 6 to 12 years of age (Garvey et al., 2003), as does the reaction time from the start signal for a reach and the actual movement to reach (KuhtzBuschbeck et al., 1998). Muller and Homberg (1992) indicate that the maturation of the motor cortex and corticospinal efferents is the main determinant of speed in repetitive movements in children. They indicate that the conduction times for afferent pathways reach adult levels by the age of 5 to 7 years, and for efferent pathways by 10 years (Muller & Homberg, 1992). In reaching, the trajectory of the arm becomes smoother and less variable (Schneiberg et al., 2002) with age. The number of units per reach decline, so that by 12 years only one acceleration-deceleration is seen (KuhtzBuschbeck et al., 1998). Older children also are better at adjusting the grip size to the size of an object; 4year-olds use a wider opening than do 12-year-olds when grip opening is adjusted for hand size (KuhtzBuschbeck et al., 1998). The coordination of the forces necessary to lift an object from a surface and the force in the fingers to hold the object during the lift also improve with age (see Chapter 3). Accuracy is improving, as is the timing of motor acts. One form of timing has been called coincidenceanticipation, or the ability to time a movement with another moving object. Bard, Fleury, and Gagnon (1990) suggest that this skill may improve linearly with age until it levels off at around 15 years. However, the authors also state that “further progress is sometimes noticed beyond this age in tasks with high degrees of stimulus uncertainty and motor response difficulty, thus placing a greater burden on decision and motor processes”. Another area in the literature that indicates continued changes in older children is in complementary two-hand use. As the child grows, the complexity of bimanual task that can be completed expands, as well as the efficiency between the two hands. Brumi (1972) looked at the abilities of 5-, 8-, and 10-year-old children to string beads, wind a string on a spool, and clap the hands. The author found that the older children tended to keep one hand stable while the other moved (e.g., in winding the thread both hands did not rotate in mirror image of each other). Fagard (1990) suggests that one of the changes taking place in older children is an increasing ability to do asymmetric tasks with the hands. She suggests that improved interhemispheric communication may assist this process. We know that children get faster with age so that the timing of movements improves. Variability decreases. Reach is smoother. Bilateral hand skills also become more complex and efficient. The adjustment of grasp and the coordination of grasp and lift movements improve. Many of these improvements are the result of maturation in motor mechanisms combined with
environmental challenges that encourage children to practice and advance their skills. Older children also show improved judgment and better control over impulsive behavior, which also improve the accuracy and quality of skilled motor activities.
SUMMARY Efficient object manipulation depends on several factors. There is the necessity to be able to differentiate the movement of individual fingers and to perform this action with speed. Manipulation skills also depend on a grip force that is firm enough to keep the object from dropping, but loose enough so that the object can be moved with ease. This ability apparently is dependent on tactile mechanisms. In addition, an object also must be released with skill and the appropriate timing. The ability to use the hands together is important also. Without the ability to plan and use both hands together in a complementary fashion, the function of the hands is severely limited. Maturation in each of these abilities assists the child’s mastery over objects and struggle toward competence. There is still much that is not known about the developmental course and changes in development that emerge as the child engages the objects in his or her environment. We need more information on how normal children develop manipulative skills. As an example, we know very little about the beginning of in-hand manipulation. There are no studies on the development of controlled release, a process that probably follows closely on how children grasp objects. The gradation of pressure as a child picks up, puts down, and manipulates objects deserves further study, as does the effect of grasp force on higher-level skills, such as holding a pen and writing. These are only a few of the areas needing future research. Object interaction is an integral part of human behavior, yet it is an area that has been poorly studied. A more complete understanding of this area of development would help both the evaluation and treatment planning of children having difficulty in achieving competency in object interaction.
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Ramsay DS, Weber SL (1986). Infants’ hand preference in a task involving complementary roles for the two hands. Child Development, 57:300–307. Rochat P (1987). Mouthing and grasping in neonates: Evidence for the early detection of what hard and soft substances afford for action. Infant Behavior and Development, 10:435–449. Rochat P (1989). Object manipulation and exploration in 2- to 5-month-old infants. Developmental Psychology, 25:871–884. Rosenbloom L, Horton ME (1971). The maturation of fine prehension in young children. Developmental Medicine and Child Neurology, 13:3–8. Ross G (1985). Use of the Bayley Scales to characterize abilities of premature infants. Child Development, 56:835–842. Ross G, Lipper E, Auld PA (1986). Early predictors of neurodevelopmental outcome of very low-birth weight infants at three years. Developmental Medicine and Child Neurology, 28:171–179. Ruff H (1984). Infants’ manipulative exploration of objects: Effect of age and object characteristics. Developmental Psychology, 20:9–20. Ruff H, McCarton C, Kurtzberg D, Vaughan HG (1984). Preterm infants’ manipulative exploration of objects. Child Development, 55:1166–1173. Ruff H, Saltarelli LM, Capozzoli M, Dubiner K (1992). The differentiation of activity in infants’ exploration of objects. Developmental Psychology, 28:851–861. Saida Y, Miyashita M (1979). Development of fine motor skill in children: Manipulation of a pencil in young children aged 2 to 6 years old. Journal of Human Movement Studies, 5:104–113. Schneck CM, Henderson A (1990). Descriptive analysis of the developmental progression of grip positions for pencil and crayon control in nondysfunctional children. American Journal of Occupational Therapy, 44:893–900.
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Chapter
9
HANDEDNESS IN CHILDREN Elke H. Kraus
CHAPTER OUTLINE DEFINITION AND CLASSIFICATION OF HANDEDNESS Defining Handedness in Terms of Handedness Dimensions
Assessment Intervention Theory Concluding Remarks SUMMARY
Classifying Handedness into Categories Description of Left and Switched Handedness PREVALENCE OF HANDEDNESS ASSESSMENT OF HANDEDNESS Tests for Hand Preference Tests for Hand Performance FACTORS DETERMINING AND INFLUENCING HANDEDNESS Neuroanatomical and Neurophysiological Foundations of Handedness Genetic Theories on Handedness Pathological Influences on Handedness Sociocultural and Environmental Influences Concluding Remarks THE DEVELOPMENT OF HANDEDNESS Birth 4 Months 6 Months 8 Months 12 Months 18 Months 24 Months 2 to 6 Years PEDIATRIC OCCUPATIONAL THERAPY AND HANDEDNESS
Handedness can be defined as the consistent and more proficient use of the preferred hand, compared with the nonpreferred hand, in functional and skilled tasks (Annett, 1985). Established handedness generally is considered to be an important indicator of hemispheric specialization and callosal myelination necessary for development of motoric skills, language, and cognitive processes (Annett, 1998; Bishop, 1990a,b). Conversely, unestablished handedness, associated with developmental delay or even pathologic conditions, sometimes reflects inadequate hemispheric specialization (Coren, 1992; Gazzaniga, 1970). From a functional perspective, the establishment of handedness is critical for successful occupational performance and development of high manual skill levels (Hurlock, 1975; Mandell, Nelson, & Cermak, 1984; Vasconcelos, 1993). It is unlikely that a child will be able to develop optimal skill if hands are changed during tasks such as drawing or writing because the preferred hand will fail to specialize to the necessary proficiency (Hurlock, 1975). Furthermore, evidence exists that motor and learning problems frequently occur in children who learn to write with the nonpreferred hand as a result of incorrect handedness classification (Ardila et al., 1988; Bishop, 1990a; Peters, 1990; Sattler, 1998, 2001, 2002). Occupational therapists should understand and meet the special needs of left-handed children, particularly in relation to handwriting. In this context, the correct identification of a child’s handedness, its promotion, and the development of manual skill in children with unestablished or left-handedness are necessary and important aspects
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in pediatric occupational therapy (Mandell et al., 1984; Sattler, 2001). Children with unestablished handedness are frequently referred to pediatric occupational therapy for other reasons, and their inconsistent hand use is usually noted informally during the process of assessment and treatment. In a survey interviewing 51 occupational therapists in Germany it was reported that overall 73% of referred children between 4 and 7 years presented with ambiguous hand use (Riedel, Künnemann, & Kling, 2002). However, handedness, particularly unestablished handedness, has received little attention within occupational therapy literature to date. Although the 1970s and 1980s resulted in an abundance of handedness literature in the field of neuropsychology, this knowledge was not comprehensively applied to, or incorporated into, the occupational therapy frame of reference. Since this time, research studies of handedness have been much fewer, and particularly unestablished or mixed handedness has received little attention in neuropsychology. Within the holistic definition of occupational performance, handedness should not be perceived as an isolated unit within a hierarchy, but rather in relation to other skills relating to occupational performance in the wider sense. Unestablished handedness in the developmental context is considered to be an indicator of neuromaturational delay (Bishop, 1990a), and the degree to which handedness is established may indicate other forms of dysfunction or pathology (see Factors Determining and Influencing Handedness). Unestablished handedness may also coexist with other behaviors such as avoidance of midline crossing and poor bimanual motor coordination, which together affect functional hand use (Ayres, 1972; Cermak, Quintero, & Cohen, 1980; Dahl Reeves & Cermak, 2002). In addition, it is possible that one hand might be prevented from gaining sufficient practice to become adequately skilled in drawing and writing tasks. Consequently, unestablished handedness is likely to retard the development of highly integrated manual skill and fine motor coordination that refine occupational performance. This chapter presents an empirical, theoretical, and developmental knowledge base for the establishment and nature of handedness to provide therapists with a more comprehensive basis for assessing and treating children’s handedness. This knowledge base draws from different approaches and is divided into six sections. First, the definition of handedness is presented, differentiating between hand preference and hand performance, and considerations for evaluating these are reviewed. In addition, the process of classifying handedness and the description of two particular types of handedness conclude the first section. The prev-
alence of handedness, followed by the assessment of handedness, comprise the second and third sections. Fourth, various factors that determine and influence handedness are presented as critical background information, and fifth, the development of handedness is outlined. In the final part of the chapter, handedness is discussed in relation to pediatric occupational therapy assessment and treatment.
DEFINITION AND CLASSIFICATION OF HANDEDNESS The definition of handedness in the literature is inconsistent and ambiguous. For the purpose of this chapter, handedness is first defined in terms of dimensions of handedness, followed by discussion on the classification of handedness into categories, with particular emphasis on consistency as an important classification factor. In this context, left and switched handedness are described in more detail. Figure 9-1 summarizes the aspects discussed in relation to the handedness definition.
DEFINING HANDEDNESS IN TERMS OF HANDEDNESS DIMENSIONS In the context of the many handedness definitions in the literature, the term “handedness” refers to a combination of hand preference and hand performance (Annett, 1998) as two dimensions of handedness. Hand preference has been defined as the tendency to perform the majority of tasks with one hand rather than the other (Nalçaçi et al., 2001). This does not necessarily mean that the chosen hand is more efficient (Porac & Coren, 1981). Moreover, hand preference has been stipulated to be the spontaneous untrained hand use as a measure of the inherent predisposition to handedness (McManus & Bryden, 1992; Olsson & Rett, 1989; Sakano, 1982; Sattler, 1998; Steenhuis & Bryden, 1989; Steenhuis et al., 1990). Conversely, hand performance is most aptly defined as the superior proficiency of one hand over the other in tasks requiring skill (Annett, 1970a). The innate motor ability interacts with environmental demands and develops with practice to varying extents of skill acquisition, which may be independent of hand preference (Porac & Coren, 1981). The distinction between hand preference and hand performance has been explored extensively (Annett, 1985; McManus & Bryden, 1992; Peters, 1996; Todor & Doane, 1977). According to Annett (1985), the inherently more skilful hand also becomes the preferred one, whereas McManus and Bryden (1992) conclude that preference precedes performance. Note that dif-
Handedness in Children • 163 Trained
Untrained
Trained
Hand preference
Untrained
Hand performance
Dimensions of handedness
Defining HANDEDNESS
Classifications of handedness
Consistency
Across tasks
Continuous spectrum
Within tasks
Categories
Explicit left
Explicit right
Mixed
Unestablished
Variable left
Switched
Variable right
Pathological
Figure 9-1 Summary of aspects related to the definition of handedness. Handedness can be defined both in terms of dimensions and classification. An important distinction is made between hand preference and hand performance as two dimensions of handedness, each with a trained and untrained aspect. Classifying handedness can be subject to observing the consistency of hand preference during task execution (across and within tasks), but in essence handedness is viewed across a continuous spectrum, ranging from explicitly left handed, to various extents of handedness variability, to explicitly right handed. However, to draw comparisons for differences and similarities between different strengths of handedness, it is useful to divide the continuum into categories: explicit left, mixed, and explicit right. The mixed category can be divided further into variable left and right handers, and unestablished (switched and pathological) handers.
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ferent assessments were used in studies supporting the preceding conclusions, which may be responsible for the contradictory findings. A cause-and-effect relationship between preference and performance is far from clear, as Peters (1996) suggested when he asked “Is it the predominance of inherent biases interacting with environmental chance events, or is it the predominant environmental influence interacting with weak inherent biases which determines the final pattern of behaviour?” (p. 118).
To date there is no clear answer to this question. The literature exploring hand preference and performance and proficiency distributions displays a variety of results in which some performance and preference tasks yield large differences between the hands (bimodal) and others do not (unimodal) (Annett, 1992; Borod, Caron, & Koff, 1984; Steenhuis, 1996). For example, there is greater discrepancy between the hands in handwriting proficiency than grip strength (Provins & Magliaro, 1989). In addition, factors such as practice or task nature may influence the magnitude of the interhand performance differences (Annett, 1992). It might be assumed that hand preference and hand performance and proficiency should be virtually interchangeable (i.e., the preferred hand is also the more skilled and proficient one and vice versa). However, the correlation between hand preference and performance has been shown to be weaker than expected. Porac and Coren (1981) suggested that preference and performance have a common underlying factor, because their correlation, although not always strong, is still significant. Furthermore, the correlations between preference and performance appear to be task dependent (see Porac & Coren, 1981, for a review). Interestingly, in some studies the correlation between preference and performance became significantly weaker when the sample was divided into left and right handers (Bryden et al., 1994; Lake & Bryden, 1976; Tapley & Bryden, 1985), indicating different patterns of preference and performance in the two groups. Furthermore, Peters (1996) found that hand preference correlated more strongly with performance in consistent handers than inconsistent handers (see Classifying Handedness). The discrepancy between preference and performance is also likely to be compounded by incompatible assessments in which hand preference often is assessed subjectively, based on self-report or inventories, whereas hand performance is evaluated more objectively through task execution (Guiard & Ferrand, 1996). The relatively low correlation between hand preference and hand performance indicates that hand function is multifaceted and multidimensional (Steenhuis, 1996). Numerous authors have attempted to identify the factors determining hand preference and hand
performance, but so far no consensus on these factors has been reached.
Hand Preference Several authors have defined hand preference in terms of types or components. Bryden (1982) proposed four “types” of hand preference: actions that require skill such as using a tool, reaching actions that do not require any skill, power actions such as carrying a suitcase (in which one is inclined to change hands because of fatigue), and bimanual actions in which both hands are involved. He found that hand preference is most significant for tool use and bimanual actions and least significant for power actions and reaching (Bryden, 1982). Healey, Liederman, and Geschwind (1986), and Geschwind and Galaburda (1987) suggested that one significant dimension of hand preference was determined by the musculature involved in task execution. There is physiologic evidence that both the contralateral and ipsilateral hemispheres control proximal arm muscles via multisynaptic pathways, whereas distal control of the hand and fingers is executed by the contralateral hemisphere via the corticospinal tract (Brinkman & Kuypers, 1973; Glickstein & Buchbinder, 1998; Haaxma & Kuypers, 1974; Peters, 1995). Support for the distal–proximal distinction was found by several authors who observed that fine manipulations performed by distal musculature appear to be more lateralized than gross motor tasks involving mainly proximal musculature (Bryden, Bulman-Fleming, & MacDonald, 1996; Peters & Pang, 1992). Other studies only partially supported these findings, suggesting that the musculature used seems to be task dependent (Case-Smith, Fisher, & Bauer, 1989; Steenhuis & Bryden, 1989). Whether and to what extent hand preference is influenced by proximal and distal musculature is yet to be empirically established. Steenhuis and Bryden (1989) proposed that the position of an object in space (i.e., ipsilateral or contralateral) influences preferred hand use, an observation already made by Ayres (1972) years earlier. In addition, Steenhuis and Bryden argued that hand preference consists of two dimensions relating to skilled and unskilled tasks. Similarly, Bishop (1990a) postulated that when the two hands are equally skilled for a task, either hand may be selected. As skill level differences increase, so does the extent of preferred hand use.
Hand Performance As with hand preference, various dimensions of hand performance have been proposed. Some researchers proposed that hand performance consists of two main factors: strength, and a combination of speed and accuracy or dexterity (Borod et al., 1984; Porac &
Handedness in Children • 165 Coren, 1981). However, several authors found that hand strength correlated only weakly with hand preference (Johnstone, Galin, & Herron, 1979; Provins & Cunliffe, 1972; Satz, Achenbach, & Fennell, 1967). Different hand performance factors identified by other researchers through component analysis (Barnsley & Rabinovitch, 1970) included reaction time, speed of arm and finger movement, arm–hand steadiness, arm movement steadiness, and aiming. All factors except reaction time revealed a significant correlation with hand preference (Barnsley & Rabinovitch, 1970).
Considerations for Evaluating Hand Preference and Hand Performance The divergent definitions in the literature demonstrate the complex nature of handedness as a multidimensional variable. Furthermore, although the multidimensional concept of hand preference and hand performance enables a more detailed understanding of handedness, no consensus has been reached on the type, parameters, and nature of the dimensions. This renders comparison between studies difficult. To overcome this problem of poor interstudy comparability, hand preference frequently has been treated as a unidimensional variable (Porac & Coren, 1981), in which all assessment items are equally weighted and, in combination, reflect a single dimension of preferred hand use. Unidimensional hand preference assessments appear accurate in determining the direction of hand preference (i.e., left or right), which can be obtained more reliably than its degree (McMeekan & Lishman, 1975). Provins (1997) and McManus (1984) believed that the direction of hand preference has a genetic basis, whereas the extent or degree of hand preference is subjected
Untrained
Hand preference Functional task performance, including spontaneous hand use
Trained
to developmental and environmental factors. Furthermore, it has been argued that the degree of handedness is a more important determinant of ability than the direction of handedness, particularly when studying individuals who lack a distinct hand preference (Annett, 1970b, 1998; Bradshaw & Nettleton, 1983; Swanson, Kinsbourne, & Horn, 1980). Occupational therapists should analyze handedness both in terms of hand preference and hand performance as two of its dimensions, because both are subjected to different levels of training. To provide a comprehensive context for a handedness assessment, the genetic predisposition and environmental factors determining and influencing the direction and degree of handedness also should be considered (see Fig. 9-2 for an illustration of these handedness dimensions).
C LASSIFYING HANDEDNESS INTO CATEGORIES The Process of Classification In general, classification of handedness in the literature appears to entail a nonspecific process that frequently involves the creation of multiple categories, ranging from three to five or more handedness groups, in which “strong” or explicit handers are distinguished from “weak” or moderate handers (Annett, 1985; Peters, 1996; Schachter, 2000). Clearly, the classification method influences the incidence of left, right, and mixed handers (Gudmundsson, 1993; see Bishop, 1990a, for a review). Rigal (1992) classified children into left, right, and mixed handers, using a score of 70% or above for established handers. These thresholds were selected arbitrarily because no natural limits exist for the “mixed” category, and the range for mixed subjects
Handedness
Untrained
Inherent predisposition Hand performance Speed, accuracy, dexterity, proficiency, skill
Environmental influence
Trained
Figure 9-2 Hand preference and hand performance as two dimensions of handedness. The two dimensions of handedness, hand preference and hand performance, are both subject to genetically based predispositions and environmental influences. The predisposition is revealed in tasks that are not trained or practiced in any way (e.g., for hand preference: building with blocks, opening a small box; for hand performance: tapping, hammering for speed), although the environmental influence is manifested in trained and practiced tasks (e.g., hand preference: brushing teeth, eating with a spoon; hand performance: drawing, cutting).
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often is varied to meet the researcher’s goals (Rigal, 1992). Others have defined left or right handedness as being 100% consistent across all tasks, and any variations from this standard were classified as mixed (Annett, 1970b). Another method to classify handedness is by means of a continuum. More specifically, strength or the degree of preferred hand use frequently has been measured as a percentage or continuous variable. Annett (1998) summarized the predicament associated with classification as follows: “The basic problem is that researchers treat a continuous variable, degree of handedness, as if it were a simple binary one (left or right). There are many ways of dividing a continuous distribution to produce a discrete one and it is often unclear precisely what was done. It is usual to find a statement of the effect that ambidextrous individuals were either discarded or counted with the left-handers, which appears to be a reasonable way of dealing with a small number of cases. However, the authors are usually confusing ambidexterity with mixed handedness and the true size of the problem of mixed handedness is simply not acknowledged. If some 33 percent of a sample can be treated arbitrarily, inconsistency of findings is not surprising” (p. 68).
In this light, Annett (1970b) derived a subgroup classification to determine whether meaningful distinctions could be made among mixed handers. She defined eight classes of hand preference, with classes one and eight consisting of “pure” right and left handers, respectively, classes two, three, four, and five were mixed right handers and classes six and seven mixed left handers. Annett found that the degrees of hand preference represented by the subgroups related reliably to degrees of hand skill (hand performance) that was assessed using a pegboard task.
Handedness Classification Annett’s work has demonstrated the usefulness of using categories of hand preference based on frequency of use. However, in line with the present definition of handedness consisting of both hand preference and hand performance, handedness categories also can be formulated in a broader sense, based on different types or presentations. Several of these presentations have been selected from various authors to provide a basis for distinction (Box 9-1). When a child presents with an unambiguous preference for either the right or left hand, and when this hand also demonstrates superior performance over the other hand, he or she has established handedness and is said to be right or left handed (Annett, 1998). Conversely, when a child swaps hands during and across tasks and thus presents with mixed handedness, this is called unestablished handedness (Whittington &
BOX 9-1
Handedness Categories
Right or Left Handed. An unambiguous preference for either the right or left hand. When this hand also demonstrates superior performance over the other hand, handedness has been established. Unestablished Handedness. Hand swapping during and across tasks, presenting with mixed handedness. The term “unestablished” is used because children are still in the process of developing. Mixed Handers. Adults and older children showing a similar presentation as unestablished handedness. Switched Handers. When children are inherently lefthanded but learn to draw and write with the right hand. Pathologic Handedness. If there is evidence of prenatal, perinatal, or postnatal trauma, and one hand is significantly weaker and inferior compared with the other hand but still shows some preference patterns. Ambidextrous. Individuals show no performance difference between the hands and can draw or write equally well with the left and right hands, although performing in the average or above-average normative range.
Richards, 1987), because children are still in the process of developing. Adults and older children showing a similar presentation are called mixed handers (Bishop, 1990a). When children are inherently left handed but learn to draw and write with the right hand, they are called switched handers (Coren, 1992). The most obvious difference between unestablished and switched handedness is the clear transition from predominantly left-handed use to right hand use because of sociocultural influences, mainly through pressure from parents, grandparents, and teachers. As discussed in the following, it is thought that hand preference can be altered by neural insult, depending on the locus and extent of lesion as well as timing (Harris & Carlson, 1988; Liederman, 1983; Satz, 1972). If there is evidence of prenatal, perinatal, or postnatal trauma, and one hand is significantly weaker and inferior compared with the other hand but still shows some preference patterns, it is likely that this is a pathologic handedness presentation (Soper & Satz, 1984). Because the majority of people are righthanded, pathologic left handers are far more frequent than pathologic right handers. Finally, ambidextrous individuals show no performance difference between the hands and can draw or write equally well with the left and right hands (Annett, 1998), although performing in the average or above-average normative range. This is extremely rare,
Handedness in Children • 167 because performance is influenced and developed through practice, and to be truly ambidextrous, both hands have to be trained equally.
Consistency The left/right/mixed classification, whether categorical or continuous, has not been the only criterion for grouping a sample population. Consistency in hand use is another important means of categorization. Although several studies have investigated handedness consistency in relation to performance domains (e.g., consistency and intelligence; Kee, 1991), the definition of consistency differs among the studies. Bishop (1990a) stressed the importance of measuring consistency within-tasks as a separate variable. She argued that inconsistent or “ambiguous” hand use within a single task (e.g., alternating right or left hand use for throwing) might be more reflective of dysfunction than a hand preference score. Consistency also can be measured across tasks, whereby high consistency reflects exclusive left or right hand performance (Peters, 1990, 1996; Peters & Servos, 1989). Thus an individual might display inconsistency by using the left hand for
certain tasks and the right hand for others, resulting in a low overall hand preference score, but show consistency within-tasks by always using the same hand for the same tasks. The across-task inconsistency and within-task consistency correspond with Bishop’s (1990a) mixed handedness described earlier. Figure 9-3 summarizes both types of consistency. Peters (1996) found that right handers showed greater strength in their preferred hand, but only consistent (across-tasks) left handers showed superior strength in their left hand, although inconsistent left handers demonstrated a stronger right hand. Peters proposed that the increased variability in left handers compared with right handers might be substantially influenced by inconsistent handers in the left handed group. More specifically, “Consistent left handers and right handers form extremes on the performance spectrum, with inconsistent left handers being intermediate in their performance. This suggests to us that the distinction between consistent and inconsistent left handers is not merely a matter of manual motor control and reaches deeper into interhemispheric communication arrangements” (Peters, p. 118).
Task 1 Writing
Task 2 Pointing
Task 3 Sewing
Task 4 Throwing
1st Trial
Left
Left
Left
Left
2nd Trial
Left
Right
Left
Right
3rd Trial
Left
Right
Right
Right
4th Trial
Left
Left
Left
Right
Within-tasks consistency (Bishop, 1990) Always uses left hand for this task (writing)
Across-tasks consistency (Peters, 1996) Uses left hand for all tasks
Across-tasks inconsistency (Peters, 1996) Uses left hand for some and right hand for other tasks
Within-tasks ambiguous hand use (Bishop, 1990) Sometimes uses left, sometimes right
Figure 9-3 Summary of definitions for consistency. Within-tasks consistency displays consistent hand use within a single task (e.g., constant use of one hand when executing a task repeatedly, such as throwing a ball). If the same hand is not used during several executions of the same task, within-tasks inconsistency is demonstrated. Across-tasks consistency reflects the same hand use across a range of different tasks, such as writing, throwing, and cutting. Acrosstasks inconsistency is displayed by using the left hand for some tasks and the right hand for others, irrespective of withintasks consistency.
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Unfortunately, research studies frequently do not differentiate between consistent and inconsistent handers within or across tasks. This might be an important classification in identifying problems associated with unestablished handedness, and therapists assessing handedness should take this into account. Furthermore, therapists particularly should have an understanding of how left and switched handers differ from right handers.
DESCRIPTION OF LEFT AND SWITCHED HANDEDNESS Left Handedness Left handers have obscured the postulate of handedness as a predictor of cerebral specialization (Bradshaw & Nettleton, 1983; Bryden et al., 1996). Although consistent left handers tend to perform much like right handers (Amazeen et al., 1997; Peters, 1996), inconsistent left handers, or left handers in general as an undifferentiated group, are not the mirror image of right handers and show different and more heterogeneous behavior as a group (Bryden et al., 1996; Dunaif-Harris, 1984). Evidence suggests that left handers in general are less strongly lateralized than right handers, and for this reason they are more likely to present with variable hand use (Bryden, 1982; Herron, 1980). Steenhuis and Bryden (1989) proposed that in comparison to right handers, left handers do not obtain lower laterality scores from lacking strength of hand preference in certain tasks (i.e., within-consistency), but because they display greater across-tasks inconsistency of preference and perform some activities with the nonpreferred hand. Furthermore, left handers appear to reflect less asymmetry and greater homogeneity of function between the hemispheres (Butler, 1997; Kim, 1994; Peters, 1985, 1987). For example, Peters (1985, 1987) used a bimanual tapping task with adults to investigate constraints in simultaneous bimanual task performance related to handedness. He found that right handers performed the bimanual tapping task better when the preferred rather than the nonpreferred hand tapped the more complex patterns. This lateralization effect was not seen in left handers, who tapped the complex pattern equally well with either hand. Other authors have found a substantial number of left handers who performed certain motor tasks better with their nonpreferred hand (Satz et al., 1967). Some authors suggested that the obvious behavioral differences in left handers might be a result of different neural and hemispheric organization (Beaumont, 1974; Hammond, 1990; Perelle & Ehrman, 1982; Peters, 1990; Satz, 1980). Others have argued that dif-
ferences between left and right handers also might be related to influencing factors such as physical environment and sociocultural milieu with a right handed bias (Coren, 1992; Harris, 1990; Porac, Coren, & Searleman, 1986; Sattler, 1998). It can be assumed that variability in left handers is probably due to a combination of these two factors.
Switched Handedness The concept of switched left handedness has received attention from several theorists (Collins, 1975, 1985; Olsson & Rett, 1989; Peters, 1990; Porac, Rees, & Buller, 1990; Sakano, 1982; Sattler, 1998, 2001; Steenhuis, 1996). Payne (1987) investigated older individuals and reported the incidence of switched left handers to be 46%, although another study found that 89% of innate left handers in the age group between 65 and 74 years had been switched, compared with 26.6% aged 35 to 44 years (Galobardes, Bernstein, & Morabia, 1999). The authors assigned the elevated percentage of switched handedness to increased sociocultural pressure in previous generations. However, it has been proposed that switched handers are not easily detected with the conventional handedness measures (Peters & Murphy, 1992; Sakano, 1982), so the prevalence may well be higher than 8%, as proposed by Porac and co-workers (1986). Individuals with an innate predisposition for left handedness are likely to present with a notable lefthanded preference during their early childhood years (Fischl, 1986; Olsson & Rett, 1989; Sakano, 1982; Sattler, 1998; Stutte, Schilling, & Weber, 1977). Parents, other family members, and teachers may exert social pressure on children to use their right hand for certain unimanual tasks that are culturally and socially important. Although there has been an increased acceptance for left handedness over the last decades, there is still evidence of existing right-biased social pressures in Western societies reflected in language and social customs (Collins, 1985; Harris, 1990; Porac et al., 1990; Sattler, 1998). Olsson and Rett (1989) suggest that some less strongly lateralized left-handed individuals are likely to succumb even to subtle pressures for right hand use, eventually resulting in switched handedness for socially important tasks (e.g., drawing, eating with cutlery, cutting with right-handed scissors). Untrained tasks, on the other hand, do not receive the same amount of attention and thus tend to be more resistant to environmental influence (Ida, Mandal, & Bryden, 2000; Olsson & Rett, 1989). With repetition and practice of task execution, the right nondominant hand can become the preferred hand for these untrained tasks (Fischl, 1986; Harris, 1990; Richberg, 1987; Sakano, 1982; Sattler, 1998; Stutte et al., 1977). However, switched handers are likely to
Handedness in Children • 169 BOX 9-2
Some Problems Associated with Switched Handedness
Decreased academic performance Inferior bimanual coordination performance Psychological abnormalities: Switching to the nondominant hand might have an unfavorable effect on cortical functioning, and functional specialization of the hemispheres may be altered through switching handedness, which in turn might interfere with interhemispheric communication processes Primary problems: Memory deficit (i.e., recalling learned material), concentration difficulty (i.e., tiring quickly, poor endurance), learning difficulties (i.e., reading, spelling), position in space problems (including poor left-right concept), speech deficit (especially stammering), and fine motor problems (e.g., handwriting) Secondary problems: Poor self-esteem, insecurity, social withdrawal, overcompensation with increased effort, oppositional and provocative behavior (e.g., playing the clown, temper tantrums), bed wetting and nail biting generally coexist with socioemotional difficulties
continue preferring their left hand for many untrained tasks and for the leading role in bimanual actions, resulting in an incomplete shift of handedness (Olsson & Rett, 1989; Porac, Rees, & Buller, 1990). Only a few studies have addressed the consequences of switched handedness (Box 9-2). They have found decreased academic performance (Ardila et al., 1988; Bryngelson & Clark, 1933; Clark, 1957), inferior bimanual coordination performance (Vaughn & Webster, 1989), and psychological abnormalities (Young & Knapp, 1966). Based on a large number of case studies, Sattler (1998, 2001, 2002) identified primary and secondary problems after switched handedness. Primary problems included memory deficit (i.e., recalling learned material), concentration difficulty (i.e., tiring quickly, poor endurance), learning difficulties (i.e., reading and spelling), position in space problems (including poor left-right concept), speech deficit (especially stammering), and fine motor problems (e.g., handwriting). Interestingly, in numerous cases, these problems decreased or even disappeared when individuals started to write with the inherently preferred left hand, even as adults (Sattler, 1998, 2001, 2002). Secondary problems associated with switching were poor self-esteem, insecurity, social withdrawal, overcompensation with increased effort, oppositional and provocative behavior (e.g., playing the clown, temper tantrums), bed wetting and nail biting, or general socioemotional difficulties (Sattler, 1998, 2001, 2002). Other authors have reported similar psychological problems as Sattler (Friedmann, 1987; Richberg, 1987;
Young & Knapp, 1966). These findings appear to indicate that switching to the nondominant hand might have an unfavorable effect on cortical functioning (Sattler, 1998, 2001, 2002). Furthermore, it has been speculated that functional specialization of the hemispheres may be altered through switching handedness, which in turn might interfere with interhemispheric communication processes (Olsson & Rett, 1989; Sattler, 1998, 2001). Initially, many children with switched handedness compensate effectively and their problems may not arise until their performance is challenged as school pressure and demands increase (Fischl, 1986; Olsson & Rett, 1989; Richberg, 1987; Sattler, 1998, 2001, 2002; Stutte et al., 1977). The nature and extent of switching effects also seem to vary greatly among individuals, whereby some appear to adapt more easily to right handedness with minimal problems, compared with others who experience great difficulties (Friedmann, 1987; Harris, 1990; Sakano, 1982; Sattler, 1998, 2001, 2002). The enormous range of variation in the presenting problems (from minimal to multiple) observed in switched handers poses a challenge in researching and understanding the handedness behavior of these individuals. Today it is generally accepted that forcing or converting left handers to become “right handers” should be avoided (e.g., Richberg, 1987; Sattler, 2002). Even Coren (1996), who appeared to favor pathologic causes as an explanation for left handedness, argued convincingly that forcing right handedness is not the answer: “Left-handedness is not a simple movement preference that has developed into a habit. It probably reflects differences in the patterns of neural circuitry in the brain” (p. 261).
Coren (1992) suggested that right hand training only produces mixed handedness or modified left handedness. It can be concluded that there is a general consensus in the literature that switched handedness is undesirable, and the importance of correct handedness classification is evident. However, the lack of specific empirical research into switched handedness and the underlying neuropsychological processes to date limit the conclusions that can be drawn on this group with variable handedness.
PREVALENCE OF HANDEDNESS The lack of coherent definitions, standard assessments, and universal classification procedures for handedness (Annett, 1998; Bishop, 1990a) makes accurate estimation of the incidence of left, right, and unestablished
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handedness difficult. As has been discussed, findings of demographic studies have considered handedness as a trinomial phenomenon in terms of left, right, and “mixed” (unestablished) handers, whereby the cut-off point for the latter group is quite arbitrary. One of the more conservative estimates states that approximately 85% of the adult population are right handed, about 10% are left handed, and 5% show mixed handedness (Coren & Porac, 1977). Other studies have provided more specific distinctions between different handedness groups. Coren (1992) differentiated between “strong” and “weak” left or right handers, suggesting that 5% present as strong left handers, 72% of people are strong right handers, and the remaining 23% demonstrate ambiguous hand use. Annett (1998) made a distinction between “ambidextrous” and “mixed” handers, in which ambidextrous handers by definition have the same level of skill in either hand, whereas “mixed” handers use their left hand for some activities and their right hand for other tasks. Annett (1998) reported only 0.3% of ambidextrous handers, but as many as 30% of mixed handers, a figure supported by Amunts and coworkers (2000). Furthermore, the prevalence of left handedness has been estimated to be 25% higher in males than females (Heim & Watts, 1976; Seddon & McManus, 1993). This gender difference may result from complex factors leading to a differential expression of laterality in females (McManus, 1991), greater testosterone levels in utero (Geschwind & Galaburda, 1987), or a possible genetic influence on handedness (McKeever, 2000). However, other studies failed to find a significant gender difference (Beaton & Mosley, 1984; Bishop, 1989; Bryden, 1977; Salmaso & Longoni, 1985). All in all, there is a general consensus that among more liberal societies, including most westernized and Caucasian-based populations, 10% to 12% of individuals are left handed (Ardila et al., 1989; Connolly & Bishop, 1992; Ellis, Ellis, & Marshall, 1988; Harris, 1990; Nicholls, 1998).
Table 9-1
ASSESSMENT OF HANDEDNESS This section provides a brief overview of general assessments, as found in the handedness literature, that appear to be useful and relevant to occupational therapists. (Specific occupational therapy assessments related to handedness are discussed further on under Pediatric Occupational Therapy and Handedness, Assessment.)
TESTS FOR HAND PREFERENCE Hand preference assessments in the neuropsychology domain typically consist of observing preferred hand use across a variety of everyday tasks, some of which are more skilled (e.g., writing and throwing) and some less skilled (e.g., picking up items, opening containers) (Ida et al., 2000; Steenhuis & Bryden, 1989). Some authors state that only items with the highest test-retest reliability should be included (e.g., Chapman & Chapman, 1987; Raczkowski, Kalat, & Nebes, 1974), whereas others question the validity of such items because of the high training element involved in most of the tasks included (e.g., Annett, 1998; Olsson & Rett, 1989; Steenhuis & Bryden, 1989; Stutte et al., 1977). In general, there appears to be no consensus on superior test items for assessing hand preference, but a mixture of both trained and untrained items appears to be the best option. One of the most frequently used tests is the standardized Edinburgh Handedness Inventory (EHI) (Oldfield, 1971). The EHI consists of 10 items (Table 9-1), which include highly skilled and trained activities such as writing and drawing, as well as less trained or skilled ones, such as opening the lid of a box. The EHI is a good choice for assessing hand preference for several reasons: It has been used extensively (Annett, 1998; Schachter 2000), including with children (Brito et al., 1992; Ross, Lipper, & Auld,
Summary of test-retest reliability of the Edinburgh Handedness Inventory (McFarland & Anderson, 1980)
Item
Pearson’s r (p < .05)
Item
Pearson’s r (p < .05)
1. 2. 3. 4. 5.
.95 .94 .90 .87 .85
6. 7. 8. 9. 10.
.84 .79 .62 .81 .69
Writing Drawing Throwing a ball Using a toothbrush Cutting with scissors
Eating with a spoon Striking a match Sweeping with a broom Using a knife for cutting Opening the lid of a box
Handedness in Children • 171 1992); has been standardized on several populations (McMeekan & Lishman, 1975; Williams, 1986); and has a high general reliability. These factors make it a superior test to other nonstandardized and less used hand preference tests, such as the Harris Test (1958) and Annett’s hand preference test (1976). However, there is evidence that the EHI is not sensitive to the degree of hand preference; children between 3 and 5 years of age scored high on this test, at an age in which the degree of handedness is still developing (Kraus, 2003). It is possible that most of the EHI items are lateralized early in life, thus displaying very similar distributions for the different age groups. Furthermore, the EHI also failed to detect significant differences between the age groups (Brito et al., 1992; Kraus, 2003). All considered, it can be concluded that the EHI is a useful tool for assessing hand preference until more sensitive measures have been developed (see Kraus, 2003, Functional Hand Preference Tasks as an example of a more sensitive measure). In the interim, the EHI can be used with some caution in addition to hand performance measures. In particular, it is useful to distinguish between trained and untrained hand preference tasks, and to draw comparisons between the two preference groups.
TESTS FOR HAND PERFORMANCE When assessing hand performance, note that superior control of one hand may not necessarily indicate that it is also the preferred hand. For example, if an innately left-handed child learns and practices to use the right hand for drawing and writing, it is possible that a higher performance level in these tasks will be achieved with the right hand, as case studies of such “switched handers” have shown (Coren, 1992; Peters & Murphy, 1992; Sattler, 1998; Stutte et al., 1977). Thus although activities such as tracing and dotting appear to be suitable for assessing forms of trained performance (i.e., hereafter called skill), hand performance should also reflect the more inherent and innate proficiency (hereafter called ability), which is relatively free of training, to obtain a more coherent understanding of the presenting variability in handedness. In addition, speed is an important factor of hand proficiency when considered in a multifactorial context (Annett, 1985; Barnsley & Rabanovitch, 1970). More specifically, speed and accuracy should be combined to achieve an accurate measure of performance (Fitts, 1954). Thus, to conduct a comprehensive hand performance test, the speed-accuracy combination should be applied in hand performance Skill (i.e., trained) and Ability (i.e., untrained) tasks (Box 9-3).
BOX 9-3
Tests for Hand Performance in Skill (i.e., Trained) and Ability (i.e., Untrained) Tasks
SKILL: Tracing and dotting: Can be performed in the context of the Motor Accuracy Test (MAc; Ayres, 1989) and the Hand Dominance Test (HDT; Steingrüber & Lienert, 1971) ABILITY: Hammering (as a form of hand tapping) and tapping (as a form of finger tapping): See Knickerbocker (1980) for a timed hammering sample and Kraus (2003) for a tapping adaptation.
Skill Tracing, a proficiency task subject to training, performed with the preferred and nonpreferred hands can demonstrate the extent to which one hand has acquired superior control as reflected in assessment tasks (e.g., Ayres, 1989; Steingrüber & Lienert, 1971). Similarly, several studies have employed timed dotting as a skilled task to assess superior hand performance (e.g., Annett, 1992a; Carlier et al., 1993; Steingruber, 1975; Tapley & Bryden, 1985). Although tracing requires continuous motor execution, dotting involves control of rapidly alternating stop-start movements and placing. Even though tracing and dotting require different types of motor prerequisites, the level of both tracing and dotting accuracy is closely related to the learned task of drawing and writing (Annett, 1992a; Steingruber, 1975; Tapley & Bryden, 1985), and they can thus be considered to be trained and skilled tasks. Tracing and dotting are two suitable skilled hand performance tasks, and they can be performed in the context of the Motor Accuracy Test (MAc; Ayres, 1989) test and the Hand Dominance Test (HDT; Steingrüber & Lienert, 1971). The MAc “emphasises accuracy or ‘steadiness’ of the visually directed hand use of a pen and is specifically designed for comparison between the more- and less-accurate hands” (Mandell, Nelson, & Cermak, 1984, p. 115).
The MAc requires timed tracing of a butterflyshaped line on an A3 paper, first with the preferred hand and then with the nonpreferred hand. The standardized version of the HDT for children consists of three parts: (a) a mazelike angled path for tracing; (b) a path of irregularly spaced circles, 0.5 cm in diameter for dotting; and (c) rows of equally spaced adjacent squares, also for dotting. All three tasks have to be attempted at maximum speed and precision for 30 seconds. The distance of the traced path is
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measured, and the number of successfully dotted circles and squares is counted. Both these standardized tests are suitable to assess hand performance skill, but they have their limitations. Kraus (2003) found that although the MAc performance level increased significantly across all age groups, the interhand differences on the test were not found to be significantly different between 3- and 5-year-old normal children. This might partly be a consequence of revisions to the MAc, including adjustments to decrease the difference between the hands (Smith, 1983). Although the MAc appears to be a valid tool for assessing performance levels, the interhand differences lack variability (Kraus, 2003), and thus sensitivity to detect more subtle differences between the hands. This needs to be considered when using the MAc as a hand performance measure. The HDT, on the other hand, has some structural drawbacks: It has angled paths for tracing, which encourages stop-start movements, and the scoring of both the tracing and the dotting task do not take the quality of the child’s response into account (i.e., a dot can also be a line as long as it is placed inside the circle). Once again, these limitations have to be considered until a more comprehensive assessment is available (see, e.g., Kraus, 2003, for the Bear Tracing Task and the Bead Dotting Task).
Ability Tapping as a motor performance task to assess innate motor ability is used most frequently in research to distinguish manual asymmetry in rapid repetitive upper extremity movements (McManus, Kemp, & Grant, 1986) as an innate and untrained task. Numerous studies have shown that the preferred hand taps faster than the nonpreferred hand (Peters, 1978, 1990; Peters & Durding, 1979; Watter & Burns, 1995). However, stipulations for tapping differ across studies, with some employing hand tapping controlled from the shoulder girdle (Peters, 1990) and others using finger tapping with stabilization of the wrist (Watter & Burns, 1995). No studies were found that investigated the difference or similarities between these two forms of tapping (i.e., whether and to what extent distally controlled tapping is indeed similar to proximally controlled tapping/hammering). For this reason, it is useful to include both hammering (as a form of hand tapping) and tapping (as a form of finger tapping) as tests to assess Ability hand performance. Knickerbocker (1980) proposed a Timed Hammering Sample to observe the “presence or absence of established hand dominance” (p. 201).
For Knickerbocker’s test, a piece of carbon paper is stapled face down between two sheets of paper and
secured to the table. The top paper features a circle 4 inches in diameter, and the child is presented with a wooden hammer in the midline. The child is then requested to hit as fast and hard as possible when the stopwatch is activated. The number of hammer blows in 15 seconds (or 20 or 30 seconds, depending on the child’s age and abilities) is recorded. The two hands are compared on the frequency of hammering blows and the quality of the hammering executions (e.g., wild uncontrolled movement, poor visual attention). The same principles can be used for tapping, although some adaptation should be made so that the wrist-generated tapping also results in “blows” on carbon paper (see Kraus, 2003, for a tapping adaptation as part of the Ability Test).
FACTORS DETERMINING AND INFLUENCING HANDEDNESS For a comprehensive understanding of handedness, one should have a knowledge base of factors that may determine, or at least influence, the establishment of handedness. Although empirical evidence concerning the determining factors of handedness remains inconclusive, there is an abundance of information relating to four different contexts: (a) neuroanatomical and neurophysiological foundations, (b) genetic theories, (c) pathological influences, and (d) sociocultural influences. Therapists should draw on this knowledge base when assessing and treating handedness in children.
N EUROANATOMICAL AND N EUROPHYSIOLOGICAL FOUNDATIONS OF HANDEDNESS Findings from scientific research link hemispheric integration and callosal maturation to many higher cognitive activities, such as complex problem solving, visuomotor coordination, language skills, and social competence, as well as handedness establishment (Chiarello, 1980; Ettinger et al., 1972; Rourke, 1987; Temple, Jeeves, & Vilarroya, 1990). When neuroscientists became aware of the functional asymmetry of the brain, they regarded the two hemispheres as a leftright dichotomy of “two minds, two consciousnesses” (Gazzaniga, Bogen, & Sperry, 1962). It was assumed that the left hemisphere was dominant and superior to the right hemisphere, particularly for speech and praxis (Gazzaniga et al., 1962; Luria, 1973; Sperry, 1974), whereas the right (“lesser, inferior”) hemisphere provided a general context to function in nonverbal,
Handedness in Children • 173 emotional, and visuospatial domains (Hécaen & Sauguet, 1971; Luria, 1973; see Beaton, 1985, for a review). Currently however, hemispheric “dominance” is viewed as relative rather than absolute, whereby one hemisphere is specialized only in relation to the other (Ornstein, 1997). This bilateral concept of “asymmetric but integrated” hemispheric roles assumes that the hemispheres operate collaboratively on all tasks, although showing flexibility in acquiring these roles should the need arise (e.g., after brain damage) (Deacon, 1997; Gazzaniga, 1995; Ornstein, 1997). In addition to the emphasis on hemispheric role integration, there is continued support in the cortical lateralization literature for specialized hemispheric function and fundamental differences in information processing (Galin, 1974; Pally, 1998; Tucker, 1981). Based on this type of neurophysiological and neuroanatomical research investigating hemispheric lateralization and specialization, it has been suggested that the two hands display asymmetric behavior because they reflect the controlling contralateral hemispheres (e.g., the left hand is superior in spatial tasks regardless of handedness) (Carson, 1989; Ingram, 1975). However, there is a lack of evidence as to whether these asymmetries are present in embryogenesis, and develop into corresponding functional asymmetries in later life, or whether anatomical asymmetries develop later as a result of learned hand use and the interaction with the environment (Hopkins & Rönnqvist, 1998). Environmental influence appears to be evident in the development of other brain structures associated with handedness establishment, such as the corpus callosum. For example, postnatal maturation of the corpus callosum appears to be significantly influenced by experience, based on great variations in callosal size, irrespective of age and gender (Bleier, Houston, & Byne, 1986; Cowell et al., 1992). In addition, there is neuroanatomical evidence that the corpus callosum differs with handedness, being approximately 11% larger in left-handed and “ambidextrous” individuals than in well-established right-handed individuals (Aboitiz et al., 1992; Bleier et al., 1986; Witelson, 1985). Gazzaniga (1970) stressed the importance of interhemispheric communication for the establishment of handedness. It has been proposed that the corpus callosum, one of the last neurologic structures to complete myelination (Farber & Knyazeva, 1991), is instrumental in manual lateralization and specialization. Myelination of the corpus callosum is thought to signal the emergence of hand preference, reflecting hemispheric specialization of cortical function (Gazzaniga, 1970). In other words, the hand–cortex relationship is considered to be a two-way process: More frequent manipulation with the right hand increases the
development of the left hemisphere, which in turn reinforces right contralateral hand use until hand/brain “dominance” is established (Gazzaniga, 1970). Although it may not yet be clear to date which parts of the brain are involved in handedness establishment, it seems important not to restrict this process to specific parts of the brain, such as the contralateral cortex. Neuroscientific evidence has emerged indicating that simple tasks tend to involve one hemisphere, whereas effective solving of more complex tasks requires both hemispheres and interhemispheric communication (Weissman & Banich, 2000). These findings suggest that, to an unknown extent, neurophysiologic involvement might be task dependent. More specifically, some authors have proposed that the task may determine handedness (Steenhuis & Bryden, 1989). As proposed in systems theory (Kelso et al., 1980), handedness could be viewed as one aspect of the neuromotor system interacting with the environment. Therefore it is important to review other possible origins and genetic, circumstantial, and environmental influences of handedness in relation to its establishment.
G ENETIC THEORIES ON HANDEDNESS Studies investigating familial handedness across generations have found support for a genetic aspect to handedness. Hicks and Kinsbourne (1976) discovered that there was a significant correlation between the handedness of college students and their parents, but only if the relationship was biological. A meta-analysis demonstrated a 1 in 10 chance of having a left-handed offspring if both parents were right handed (Porac & Coren, 1981). If one parent was left handed, particularly the mother, this ratio doubled to 2:10, and if both parents were left handed, the chance of left handedness further increased to 4:10 (Bryden et al., 1996; McManus & Bryden, 1992; Porac & Coren, 1981). Other studies have found an even higher ratio between left handers and their left-handed parents. For example, Annett (1978, 1985, 1995) assessed the difference in skill level between the hands rather than preferred hand use, excluding parents who might have been pathologic left handers. She found a 50% prevalence of left-handed offspring from two lefthanded parents. Several genetic theories have attempted to explain the incidence of left handedness. Annett’s (1972, 1985, 1994, 1995) well-known right shift theory postulates that handedness is influenced by an inherited factor rather than being inherited directly. A single gene is thought to be responsible for displacing handedness, assumed to be a random or chance phenomenon, toward the right (i.e., right shift). One allele causes right handedness and another allele results in the
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independent and random lateralization of manual praxis. Those individuals homozygous for the random factor have a 50% chance of being left or right handed. Two factors influence the handedness outcome and hemispheric specialization for speech: a genetic right shift (RS+) factor, and a random congenital but nongenetic factor that codes for speech representation in the left hemisphere. Right handedness is linked to left hemispheric speech representation, and thereby determined by the genetic RS+ factor, whereas the random factor implies that left handedness and left hemispheric speech representation are not inherited. According to Annett’s model, approximately 25% of individuals presenting with atypical patterns of hemispheric specialization (i.e., right and bilateral cerebral speech representation) become left handers. However, Annett argued that the right-biased cultural and environmental influences increase the development of right handedness, so that the incidence of left handers is reduced to approximately 16%, which is congruent with her prevalence studies based on hand skill (Annett, 1998). Furthermore, Annett has proposed that the strength of handedness is inheritable, because some individuals may be homozygous for the RS factor (i.e., RS++), displaying a stronger handedness than individuals who are heterozygous (i.e., RS±). Annett’s model has been criticized for lack of empiric support for the 50% frequency of both dominant and recessive alleles, and the assumption that hand performance and hand preference covary (Hopkins & Rönnqvist, 1998; Porac & Coren, 1981). Similarly to Annett, the authors McManus and Bryden (1992) argued for a single gene with two alleles indirectly determining handedness, namely Dextral (D) and Chance (C). Individuals with a Dextral-Dextral (DD) genotype are right handed, whereas persons with a Chance-Chance (CC) genotype have an equal chance of being left or right handed. Heterozygous individuals (DC) received proposed “additivity,” having a 25% chance of being left handed as opposed to a 75% chance of becoming right handed. Unlike Annett, the authors proposed that handedness and hemispheric specialization are coded independently of one another, and the presence of a sex-linked moderator gene accounts for the increased incidence of left handedness in males. The central idea of the genetic models appears to be similar. Approximately half of the population inherits the potential to become either left or right handed, but only a proportion of these individuals eventually present as left handers. The genetic models could possibly explain the variation in strength of handedness because variable handers might include those individuals who have an equal chance of being left or right handed. However, twin studies have compounded the complexities involved in the inheritance of handedness,
because monozygotic twins sharing identical genetic make-up do not necessarily present with the same handedness (Oberleke, 1996), and the incidence of handedness discordance is as high as 25% (CarterSaltzman et al., 1976). Thus current genetic models do not convincingly explain the reduced handedness concordance in monozygotic twins (Stein, 1994), nor is there certainty as to what proportion of people should “genetically” be left handed, particularly if the sociocultural and environmental factors reduce the phenotypical presentation of left handers to an unknown extent. Nevertheless, the increase in ratios of left-handed offspring from left-handed parents, including the handedness concordance in 75% of identical twins, suggests at least a genetic component to the handedness phenomenon (Bryden et al., 1996). Furthermore, it has been proposed that the “strength” of handedness is inherited, with some individuals presenting with strong left and right handedness, whereas others show greater variation in their preferred hand use (Bryden, 1982; Coren, 1992; Coren & Porac, 1980). Recent findings also suggest that there is an X-linked pattern of genetic influence on handedness (McKeever, 2000). However, to date no handedness gene or allele has been identified that could ascertain the direction and extent of handedness, and genetic theories thus remain incomplete. The assumption that a genetic composition is responsible for the direction of handedness permits left handedness to be a “normal” inherited trait in a minority of people. At the same time, most genetic theorists do not account for prenatal, perinatal, and postnatal influences that may increase the incidence of left handedness.
PATHOLOGIC I NFLUENCES ON HANDEDNESS Models linking intrauterine influences and birth stress with handedness appear to be based on the assumption of a genetically predetermined right handedness in humans. Generally, these models propose that left handedness is a failure to become right handed and is thereby rendered abnormal, “anomalous” (Geschwind & Galaburda, 1985, 1987), or pathologic (see Harris & Carlson, 1988, for a review on existing theories relating to pathologic left handedness). The GeschwindGalaburda theory is the most prevalent and controversial intrauterine model for the cause of left handedness. It is based on the premise that anatomical asymmetries, evidently already present in utero, result in functional asymmetries (Geschwind & Levitsky, 1968). Geschwind and Galaburda (1987) suggested that growth-retarding influences of chemicals and hormones, particularly testosterone, are most likely to affect the more vulnerable left hemisphere because of its slower rate of
Handedness in Children • 175 development. As a result, the anatomical brain asymmetries are reduced and the hemispheres become more symmetric, which leads to anomalous dominance with equal chances of becoming left or right handed. The authors proposed that left handedness results if the right hemisphere becomes more specialized. In addition, variations in the chemical environment may cause the variability typical of left handedness. The testosterone hypothesis has been extensively reviewed and questioned. Brain imaging studies have supported the link between anatomical asymmetries in language-related brain areas and hand preference (see Foundas, Leonard, & Heilman, 1995; Steinmetz et al., 1991, for a review). However, there are no longitudinal studies to indicate if the observed anatomical asymmetries in utero are related to corresponding functional asymmetries in later life. Recent evidence also suggests that brain symmetry appears to be triggered by trophic changes in the right hemisphere rather than growth retardation in the left hemisphere (Galaburda et al., 1987; Habib, Touze, & Galaburda, 1990). Moreover, if hormonal imbalances do exist, twins subjected to identical intrauterine factors should present with identical handedness, which is not necessarily the case (Oberleke, 1996; Stein, 1994). In addition, males are subjected to greater testosterone levels than females, which, according to Geschwind and Galaburda (1987), should result in a significantly higher incidence of “atypical” handedness in males. However, as has been noted, significant gender differences were found in some prevalence studies but not others. More recently, an increased incidence in left handedness was revealed in male individuals who were exposed to ultrasound in utero, which has been considered another factor responsible for shifting inherent right handedness to left handedness (Kieler et al., 1998). However, intrauterine conditions do not appear to be the only early influence on handedness development. Just as abnormal prenatal intrauterine conditions may affect the development of hemispheric specialization, unfavorable perinatal and postnatal circumstances, including birth-related stress, seem to have a similar or even more prevailing effect (Coren, 1992). Birth-related stress has been cited as one of the most potent acquired influences on handedness outcome (Bakan, Dibb, & Reed, 1973). It has been proposed that the “dominant” hemisphere, which may not necessarily be the left, is most likely to be affected by early brain damage (Best, 1988). Goodman (1994) tested the hypothesis of corresponding hemispheric and manual dominance by investigating 463 children with hemiplegia in relation to familial handedness. Unexpectedly, he found a highly significant correlation between right hemiplegia and familial left handedness. Goodman interpreted the results as evidence against the notion of
a more vulnerable “dominant” hemisphere, and rather in support of a more vulnerable left hemisphere. Other evidence exists to support greater vulnerability of the left hemisphere, based on a higher ratio of children with right hemiplegia (Uvebrandt, 1988). Several reasons for the increased vulnerability of the left hemisphere have been proposed. First, the blood supply to the left hemisphere has less volume (Raichle, 1987). Second, the right hemisphere matures more quickly and earlier than the left hemisphere, thus the latter is more likely to be damaged (Jacobson, 1978), being particularly vulnerable to intracranial focal lesions and intracranial hemorrhage (Schuhmacher et al., 1988). Third, the left hemisphere requires more blood for metabolism and burns oxygen more quickly (Bakan, 1977). Fourth, the hormonal imbalances, especially testosterone, appear to affect the left hemisphere more strongly (Geschwind & Galaburda, 1987). In the case of early neural insult affecting the left hemisphere, the right hemisphere is thought to compensate by assuming a more active role, resulting in pathologic left handedness (Orsini & Satz, 1986; Rasmussen & Milner, 1977; Soper & Satz, 1984). Several prenatal, perinatal, and postnatal factors related to the birth process have been associated with an increased incidence of pathologic left handedness. These factors include birth weight (O’Callaghan et al., 1987), prematurity (Ross et al., 1987), difficult delivery and induced birth (Colbourne et al., 1993), the mother’s age (Coren, 1992), and smoking during pregnancy (Bakan, 1991). It has been suggested that these factors might later result in associated disorders such as dyslexia (Eglington & Annett, 1994), attention deficit disorder (ADD) (Gillberg & Rasmussen, 1982), learning disability (Geschwind & Galaburda, 1984), and intellectual disability (Fein et al., 1984). However, some studies have failed to find support for an association between left handedness and pathologic conditions (Bishop, 1990). It has been argued that the proposed elevated incidence of “pathologic” left handedness is based almost exclusively on clinical groups that consist of twice as many left handers as the normal population (Perelle & Ehrman, 1982; Satz, 1972), and there is little evidence of an association between left handedness and pathology in the general population (Annett, 1992; Hardyck & Petrinovich, 1977; Satz, Soper, & Orsini, 1988). Considering the evidence for a genetic versus intrauterine or birth-related stress basis for handedness, it is generally accepted that left handedness consists of two subgroups: familial (genetically based) and pathologic (caused by brain damage). Distinguishing between these two subgroups may produce different research outcomes about comparisons between left and right handers (Annett, 1985; Hécaen & Sauguet, 1971;
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McKeever, 1981; Orsini & Satz, 1986). To date, there is no agreement on the definition of pathologic left handedness. There are those researchers who suggest that pathologic left handedness appears to develop only with substantial damage to the left hemisphere (Annett, 1985; McManus & Bryden, 1992; Satz et al., 1985), in which case the incidence of pathologic left handedness is relatively low. Conversely, other researchers propose that pathologic left handedness is a result of relatively minor neurologic trauma. In the latter case, at least half of all left handers or even all left handers are thought to demonstrate left handed behavior with a pathologic origin (Coren, 1992). Taking an even more extreme approach in the absence of strong genetic evidence for left handedness, Bakan (1990) considered all left handedness to stem from some form of pathology. Hopkins and Rönnqvist (1998) emphasized that strongly lateralized and unusually consistent hand preference during infancy, rather than fluctuating asymmetry, may be indicative of underlying neuropathology. It has been specifically suggested that poor performance of the nonpreferred hand might be suggestive of early brain damage (Bishop, 1984; Gillberg, Waldenstrøm, & Rasmussen, 1984). This may affect the left or right hand. There is indeed evidence for the existence of “pathological right handers” (Kim et al., 2001), referring to a group of familial left handers who experience early right brain injury and consequently develop right hand preference. However, the incidence of pathologic right handers has been estimated to be low because of the restricted number of familial left handers (Satz, 1972, 1973). Finally, if handedness is a manifestation of the extent of interhemispheric communication via the corpus callosum, clinical research should reflect a link between variable handedness and callosal dysfunction. There is evidence that dyslexia, which also has been linked to a greater incidence of unestablished handedness (Satz & Fletcher, 1987), appears to be related to poor hemispheric lateralization (Galaburda, 1993; Satz, 1991), and poor interhemispheric communication (Gladstone, Best, & Davidson, 1989; Kerschner, 1983). However, other studies have failed to find support for an association between learning disabilities and unestablished handedness (Bishop, 1990a,b). Also, magnetic resonance imaging (MRI) of the corpus callosum did not reveal differences in callosal size between dyslexic and normal children (Larsen, Höien, & Ödegaard, 1992). In summary, the proposition that unusual prenatal, perinatal, and postnatal conditions influence the cerebral lateralization process of the immature brain is supported by empiric evidence. Although many of the findings remain inconclusive, the impact of early unfavorable conditions on hemispheric specialization has not been disputed to date. However, intrauterine
models do not account for the increased incidence of familial left handedness, suggesting a genetic component. Furthermore, these models fail to consider sociocultural influences that are likely to cause an increased occurrence of right handedness.
SOCIOCULTURAL AND E NVIRONMENTAL I NFLUENCES Genetic, intrauterine, and birth-related stress theories have concentrated on predispositions and early factors that could determine, influence, and change the handedness outcome. However, handedness is undeveloped at birth, and becomes established within the first 5 to 6 years of life (Tan, 1985). Although the direction of handedness already may be apparent in infancy and is considered to be stable by 5 years (McManus et al., 1988), the degree and consistency of handedness are subject to change, particularly up to the age of 9 years (McManus et al., 1988; Goodall, 1984), 11 years (Whittington & Richards, 1987), or even across the entire life span (Porac & Coren, 1981). There is also some evidence that handedness establishment takes place earlier in right handers (i.e., by 5 years of age) than left handers (i.e., by 9 years) (Mandell et al., 1984). Environmental and cultural influences are likely to have a significant effect on handedness, although there is little empiric support for handedness as a sole product of cultural influences. For example, children of left-handed foster parents do not exhibit an increased use of the left hand (Carter-Saltzman, 1980). Furthermore, in many societies it is far more likely that sociocultural influences restrain left handedness, forcing, or at best encouraging, left handers to use their right hand (Harris, 1990). One of the more extreme examples is the account of Chinese children at Taiwanese schools, in which the incidence of left-handed writing is only 0.7% (Teng et al., 1976). However, no evidence was found that forced right-handed writing also resulted in increased right hand use in other activities. There is empiric support that the number of left handers is significantly higher in younger individuals than in older ones, both in cross-sectional and longitudinal studies (Coren, 1992; Hugdahl et al., 1993; Porac & Coren, 1981; Porac et al., 1986). Stricter sociocultural pressures to use the right hand for socially important tasks were imposed particularly on previous generations, a phenomenon that has been described in the “modification hypothesis” (Coren, 1992). This hypothesis asserts that the existing right-handed bias in the sociocultural and physical environments coerces left handers to “switch” handedness to the right (Coren, 1992; Sakano, 1982). However, the modification theory has only addressed switching of well-established left handers. It is plausible that individuals with a mild
Handedness in Children • 177 left-handed predisposition are most vulnerable to rightbiased sociocultural pressures. Therefore it is possible that inherently mildly established left handers constitute a proportion of unidentified switched handers within the right-handed population.
CONCLUDING REMARKS In summary, hand preference can be perceived as a multicausal behavior that is influenced by a variety of mechanisms, including genetic and nongenetic factors. As Provins (1997) contended: “what is genetically determined is a neural substrate that has significantly increased its functional plasticity in the course of evolution. … What is fine-tuned is the relative motor proficiency or skills achieved by the two sides in any given task according to the use and the demands made on them as a result of social pressure, other environmental influences or habit” (p. 556).
Although the origin and cause of manual lateralization are still debatable, the prevalence of left and right handedness appears to have existed fairly constantly since prehistoric times (Bradshaw & Rogers, 1996; Calvin, 1983; Corballis, 1983; Steele & Mays, 1995; Toth, 1985) and across most human societies (Hardyck & Petronovich, 1977; Harris, 1980, 1990; Peters, 1995). It could be concluded that handedness is a unique human trait, displaying a wide variety of degrees of presentation that are not yet well understood. In contrast, the development of handedness has been well documented since the 1940s, as reviewed in the following section.
THE DEVELOPMENT OF HANDEDNESS Occupational therapists should have good understanding of handedness development because this forms an important basis for the intervention phase. Defining a developmental process of a particular behavior in the holistic context of occupational performance most often requires the inclusion of related behaviors. This is also the case with the development of handedness, in which the hands tend to be used initially in the ipsilateral hemispace before contralateral reaching with the preferred hand is observed (Provine & Westerman, 1979; Pryde, Bryden, & Roy, 1999). Furthermore, handedness is expressed both unimanually and bimanually (Hopkins & Rönnqvist, 1998). In particular, Fagard (1998) argued that stabilization “of unimanual handedness might be one of the factors influencing the emergence of the capacity to use both hands in
cooperation… Bimanual complementary movements often consist of more than one step or action, in which each hand plays a different role. The flexibility in shifting attention between hands might therefore be one prerequisite for bimanual success” (p. 125).
In a neurodevelopmental context it seems appropriate to follow the emergence of handedness in relation to midline crossing and bimanual coordination. The different developmental stages are discussed in the following, first in relation to handedness with reference to the developmental stage of the corpus callosum, then to midline crossing, and finally to bimanual coordination.
BIRTH At birth, the corpus callosum is underdeveloped and nonfunctional (Gazzaniga, 1970; Hewitt, 1962), developing over the next 10 years at an unprecedented rate compared with its later development. Movement of the upper limbs has been described as uncontrolled and reflexive, and is performed both symmetrically and asymmetrically (Fagard, 1990, 1998), with the presence of the asymmetrical tonic neck reflex (ATNR) and the Moro reflex. These seemingly random movements are closely linked to the lack of postural control at this age. For example, when the head of a neonate is stabilized externally, reaching is possible (Amiel-Tison & Grenier, 1980). However, adequate postural control is necessary to enable independent reaching by the infant, so reaching does not occur spontaneously at this age (Shumway-Cook & Woollacott, 2001). Furthermore, the infant is unable to cross the midline, even when the body is fully supported and one limb is restrained (Provine & Westerman, 1979).
4 MONTHS According to Gazzaniga (1980), each hemisphere processes sensorimotor information independently of the contralateral side. This activity might indicate that the corpus callosum is starting to play a role in relaying information from one hemisphere (e.g., visual field) to the other (e.g., controlling contralateral motor performance). Hand preference coincides with unilateral swiping of either hand (Gesell & Ames, 1947) and a decrease in the grasp reflex that is replaced with a crude but voluntary grasp (Case-Smith, 1995). Provine and Westerman (1979) found that this is the earliest time that infants are able to cross the midline when one hand is restrained (see also Murray, 1995, for a review). Bimanual movements are symmetrical or mirrorlike and simultaneous, resulting soon in bilateral body and object exploration, and hand interplay in midline (Fagard, 1990, 1998; Fagard & Pezé, 1997).
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6 MONTHS Gazzaniga (1980) proposed that the corpus callosum first demonstrates increased myelination, reflected in the emergence of unilateral reach. Alternating with the bilateral development, a first (transient) preference for unilateral, usually the right hand, use becomes apparent (Gesell & Ames, 1947). As the infant’s postural control develops in sitting, weight is borne on one arm for pivoting, and the infant reaches with the other hand to the contralateral side using trunk rotation (Case-Smith, 1995; Gilfoyle, Grady & Moore, 1990). No active contralateral reaching has been recorded at this stage. There is a definite shift toward bilaterality (Gesell & Ames, 1947) from simultaneous to successive movement (Castner, 1932). For example, the infant holds an object in one hand and reaches with the other (White, Castle, & Held, 1964), or movement is initiated with one hand and completed with the other (Castner, 1932).
8 MONTHS The emergence of a more radial palmar and then digital grasp (Gesell & Amatruda, 1947) precedes a unilateral phase whereby there is increased left hand use, followed by a greater persistence of right hand use. Further refinement of postural control is now evident (CaseSmith, 1995; Gilfoyle et al., 1990), but no active contralateral reaching has been recorded at this stage. Infants start to hold two objects simultaneously in each hand and combine this with a bimanual symmetric action, such as banging (DeSchonen, 1977; Fagard, 1990, 1998; Fagard & Pezé, 1997).
12 MONTHS As the corpus callosum continues to develop, the emerging pincer grasp coincides with another phase of more unilateral left hand performance, followed by a phase of using either hand (Gesell & Ames, 1947). Having achieved good postural control in sitting, the infant is now able to reach into either contralateral space using trunk rotation but without employing arm support. However, this midline crossing occurs mainly when one hand is occupied, not yet reflecting a preferred hand. Ipsilateral reaching is still preferred (Carlson & Harris, 1985; Case-Smith, 1995; Knobloch & Pasamanick, 1974), although Bruner (1969) suggested a diminished “midline barrier” at this stage. The hands begin to work together in an increasingly complementary fashion and coordinated asymmetric roles (Goldfield & Michel, 1986), in which one hand is more active, the other more passive. Bimanual hand preference emerges after 9 to 10 months of age, involv-
ing temporal and spatial coordination and complementary action. Sequential rather than simultaneous bimanual activity is performed (Fagard, 1998; Fagard & Pezé, 1997).
18 MONTHS Around this age, the left hemisphere develops more rapidly than the right (Jacobson, 1978). The clear shift toward unilateral hand use continues, alternating with much bilateral activity, and inconsistent hand use is still apparent (Gesell & Ames, 1947). Other researchers have observed a clear hand preference in bimanual tasks after 14 months (Michel, Ovrut, & Harkins, 1985; Ramsey, Campos, & Fenson, 1979), concluding that unimanual hand preference precedes bimanual hand preference. More recently, Fagard and Marks (2000) compared unimanual and bimanual tasks in relation to hand preference in babies aged 18 to 36 months. They found that bimanual tasks elicited a stronger role differentiation than unimanual tasks even at 18 months. They deduced that hand preference is task related, and that certain bimanual tasks might display greater asymmetry than unimanual tasks in infancy. At this stage, the first active contralateral reaching across the body is observed (White et al., 1964), without one hand being occupied or used for support. Children are now able to combine stabilizing the object with one hand and manipulating it with the other in an alternating manner (Gilfoyle et al., 1990), which leads to more mature bimanual coordination (Corbetta & Thelen, 1996; White et al., 1964).
24 MONTHS The corpus callosum appears to be functioning at a basic level and inhibitory function is emerging (Farber & Knyazeva, 1991). There appears to be a preference for bimanual activity in which the preferred hand is more active and the nonpreferred hand has a stabilizing and assistive role (Fagard & Marks, 2000). At this stage, most young children show a more definite preference for the right hand (Gesell & Ames, 1947) because the fingers and arms are increasingly dissociated for a large variety of functional skills (Case-Smith, 1995). Stilwell (1987) found that 2-year-old children actively cross the midline, more so with their preferred hand. The hands can now be used in all planes with good control (Gilfoyle et al., 1990). Two-year-old children can also perform a sequence of bimanual movements whereby the arm and hand stabilization and movement are controlled simultaneously (Knobloch & Pasamanick, 1974), such as holding a crayon and drawing, or threading beads.
Handedness in Children • 179
2 TO 6 YEARS MRI studies have supported age-related increases in cerebral white matter and myelination of the corpus callosum in children and adolescents (DeBellis et al., 2001; Giedd et al., 1999; Thompson et al., 2000). There is evidence that callosal transfer is not optimal until approximately 10 to 12 years (Yakovlev & Lecours, 1967), and that subsequent sensorimotor and cognitive development further increase the callosal interconnections between the hemispheres up to adulthood (Pujol et al., 1993). By the third and fourth year, the direction of hand preference is evident (McManus et al., 1988) and there is a tendency toward unilateral activity (Gesell & Ames, 1947). This stage appears to be followed by another period of well-differentiated bilaterality between 5 and 7 years of age. Hand preference becomes fully established between 6 and 9 years of age (Gesell & Ames, 1947; Tan, 1985). At the age of 6 years children use the preferred hand consistently to cross the body midline (Stilwell, 1987). However, more complex tactile tasks requiring crossed localization conditions demand a higher level of interhemispheric transfer via the corpus callosum (Fabbro, Libera, & Tavano, 2002). Children aged 5 to 6 years make significantly more errors than 10-year-olds (Quinn & Geffen, 1986). Children are increasingly able to execute complex activities requiring differentiated hand performance, in which the asymmetrical and functional role differentiation becomes more refined throughout childhood (Fagard, 1990, 1998). Symmetrical in-phase coordination between the hands is evident at 5 years (Fagard, 1987), but inconsistent coordination patterns are still observed in children between the ages of 6 and 10 years (Haken, Kelso, & Bunz, 1985). Unimanual action such as grasping might strengthen the contralateral unilateral control system during infancy (Fagard, 1998). This allows one hand to take responsibility and lead, which in turn influences hand preference and the dissociation between the hands. Bimanual action, on the other hand, allows infants to use both hands in succession until they are able to coordinate their hands in an asymmetrical and simultaneous manner (Fagard, 1998). With maturation, reaching and grasp extend to midline and then to the contralateral space, possibly indicating a shift in interhemispheric communication from extracallosal to callosal control (Liederman, 1983). This contralateral reaching or midline crossing has been defined as “hand movements that approach and/or cross the centre longitudinal axis of the body (the body midline)” (Stilwell, 1994).
In summary, the development of handedness appears to fluctuate between unimanual and bimanual preferences that seem to be individually paced. Hand function initially takes place only in ipsilateral and midline spaces, and later extends to the contralateral space. This developmental process supports the neurophysiological basis for an intricate relationship among hand preference, midline crossing, and bimanual coordination and appears to be closely linked to the development of the corpus callosum.
PEDIATRIC OCCUPATIONAL THERAPY AND HANDEDNESS ASSESSMENT Tests Used in Occupational Therapy There is a lack of specific test procedures in occupational therapy to assess handedness. The Mesker test was designed specifically to assess writing handedness for children at school entry (Mesker, 1972). This test was used by occupational therapists in the United Kingdom and involves simultaneous drawing with both hands. However, findings from an evaluative study indicate that hand preference could not be confirmed definitely using the Mesker test (Warren & McKinlay, 1993). Two assessments that include aspects of handedness in children are frequently used in occupational therapy; the Southern California Sensory Integration Tests (SCSIT) (Ayres, 1980) and the Sensory Integration and Praxis Tests (SIPT) battery (Ayres, 1989). Because there is some evidence that “limitations in development of unilateral hand preference may be associated with poor functional integration of the two sides of the body … [and] with diminished preferred-hand visuo-motor coordination” (Ayres & Marr, 1991, p. 233),
there is an advantage of using the SCSIT or SIPT to obtain a more holistic picture of handedness. The two tests combine the assessment of preferred hand use, hand performance, midline crossing, and bilateral motor coordination, in addition to other behaviors related to sensory integrative dysfunction. In the SCSIT and SIPT, midline crossing is closely related to preferred hand use: The therapist observes to what extent the preferred hand is used for contralateral reaching. In addition, hand performance is assessed in both hands by means of a tracing task, with scores
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incorporating both time and accuracy. However, note that although the inclusion of handedness-related information was initially aimed at detecting the extent of hemispheric specialization (Ayres, 1980, 1989; Murray, 1991), contemporary sensory integration is primarily concerned with deficits in the central processing of tactile, proprioceptive, and vestibular sensations and the integration of these into adaptive responses (Bundy & Murray, 2002; Windsor, Smith Roley, & Szklut, 2001). Although the SCSIT and SIPT test batteries still contain and use measures of preferred hand use, motor accuracy for both left and right hands, and a midline crossing measure, the purpose of these measures is to obtain information on laterality establishment in general rather than handedness, because it is considered to be an important component for detecting bilateral integration and sequencing (BIS) deficits. In both the SCSIT and SIPT, preferred hand use (i.e., the measure of hand preference) is obtained by first recording the hand that initially uses the pen to draw. However, it is essential not to assume that a highly trained task such as drawing and writing provides an accurate reflection of hand preference, because these tasks are subject to sociocultural influences (Ida, Mandal, & Bryden, 2000). The inclusion of an additional test with more opportunity to demonstrate hand preference across a range of functional tasks is thus necessary. It seems evident that the multidimensional nature of handedness requires a careful multifaceted assessment in which hand preference, hand performance, consistency, and interhand differences are recorded. In addition, an assessment of bimanual coordination and
midline crossing contribute to a more functional analysis of handedness, although background information on early hand use, familial handedness, and possible prenatal, perinatal, or postnatal trauma could provide some context to the influences of handedness establishment. A test battery addressing all of these facets, the Handedness Profile, has been proposed by Kraus (2003). The test battery includes a Handedness Profile Chart, that summarizes both the extent of interhand differences (ranging from explicit left L+, moderate left L–, variable V, moderate right R–, to explicit right R+ handedness), and performance levels for six handedness aspects (Fig. 9-4). In addition, the Handedness Profile features a Diagnostic Summary that incorporates background information and qualitative information on each of the handedness aspects to assist the final diagnostic classification of the type of presenting handedness.
I NTERVENTION THEORY Unestablished Handedness Occupational therapy intervention for unestablished handedness has its roots in perceptual motor theory (Keogh & Sugden, 1985; Kephart, 1971; Lerch, Becker, & Nelson, 1974), sensorimotor principles (Knickerbocker, 1980), and sensory integration (Ayres, 1972, 1989). Laterality has been defined by early perceptual motor theorists as “the internal awareness of the two sides of the body and their difference” (Kephart, 1971, p. 88).
Performance Level Below
Border
Average
Inter-Hand Difference Handedness Aspect
L⫹
L⫺
V
R⫺
R⫹
Untrained FHP
Trained FHP Skill Ability Midline Crossing Bimanual Coordination
Figure 9-4 Example of a handedness profile chart combining performance levels and interhand differences. Note: FHP = Functional Hand Preference, L+ = explicit left handedness, L– = moderate left handedness, V = variable handedness, R– = moderate right handedness, R+ explicit right handedness. This handedness profile is based on an 8-year-old boy with PDD who had left-handed tendencies but was encouraged at home and in therapy to use his right hand. (Kraus, 2004)
Handedness in Children • 181 In this context, the development of laterality was thought to underlie the establishment of handedness: When a child is able to differentiate the two sides from each other, one side becomes more “dominant.” The emphasis in the perceptual motor approach is on the establishment of laterality, and handedness is considered to be a by-product (Kephart, 1971). Although some early sensorimotor training programs aimed at improving body image and laterality have resulted in increased contralateral reaching (Ball & Edgar, 1967; Maloney, Ball, & Edgar, 1970), the broad definition of laterality fails to specifically address handedness. Indeed, handedness should not be considered synonymous with laterality, because the correlation between handedness and other modalities (foot, eye, and ear) is variable. Footedness (as assessed through kicking) appears to be most strongly related to handedness, with about 85% of right handers and 80% of left handers using their right and left feet, respectively (McManus, 2002). However, clinical experience has indicated that one-leg standing balance, another task used to assess the preferred leg, does not appear to correlate strongly with kicking, possibly because the nonkicking leg needs to acquire good balance to support the kicking leg (Kraus, 2002, personal observation). Eyedness has been assessed and it was found that about 70% of people demonstrate right eye preference and 30% left eye preference: Although there is a correlation between eyedness and handedness, it is rather weak (McManus, 2002). Finally, earedness correlates even less with handedness, because only about 60% of people listen with the right ear and 40% show left ear preference (McManus, 2002). The importance of the lateralization of these modalities remains controversial, particularly because there is a lack of empirical evidence that they reflect brain and language specialization more accurately than handedness (Bryden et al., 1996). The concept of “cross-dominance” (i.e., hand-, foot-, eye-, and eardominance are not congruent) was introduced by Orton (1925, 1937), who proposed that “crossdominance,” particularly between hand and eye preference, is associated with dysfunction such as dyslexia, a theory supported by other early perceptual motor theorists (Delacato, 1963; Harris, 1957; Rengsdorff, 1967). However, more recent research has challenged these early theories, because no relationship was found between them and a mixed or “crossed” dominance profile and intelligence or achievements (Sulzbacher et al., 1994). Other existing asymmetries or lateralities in humans, such as arm folding, hand clasping, and leg crossing, have been researched because they are not subject to any learning. Luria (1973) and Sakono (1982) suggested that these lateralities can denote “latent left handedness,” which could explain why some individuals were more likely to recover from
aphasia after unilateral left hemisphere brain damage. However, the supplied evidence is rather weak (Bryden et al., 1996), and it has been suggested that these types of lateralities are inherited genetically and not related to brain lateralization (McManus, 2002). Traditionally, clinicians have considered laterality to be a sensorimotor-based phenomenon that becomes established independently of the child’s knowledge of left and right, and it is thought to be stabilized when the child has acquired the left-right concept (Williams, 1983). This concept of laterality assumes hierarchical functioning of the central nervous system, in which laterality is deemed necessary for higher-level movement efficiency, symbol recognition, and directionality (Knickerbocker, 1980). Therapy promoting the establishment of handedness within the perceptual framework aims to improved general body awareness, body image, crossing the midline, and directionality (Knickerbocker, 1980). Adopting a similar bottom-up approach within a sensory integrative frame of reference, Ayres (1972) initially suggested that integration of proprioceptive and vestibular sensations, as well as efficiency of interhemispheric connections, were fundamental to good bilateral integration and the establishment of a preferred hand in contralateral space. Since then, sensory integration theory has refined these concepts or expanded on Ayres’ propositions by linking theoretical postulates to clinical practice and sensory integrative therapy using case examples (Dahl Reeves & Cermak, 2002; Kimball, 1999; Koomar & Bundy, 1991, 2002; Murray, 1991; Windsor et al., 2001). More specifically, some authors suggested that the inclusion of trunk rotation is important in developing bilateral integration and crossing of the midline (Kimball, 1999; Koomar & Bundy, 1991, 2002). These authors proposed that employing these behaviors together in therapy might assist in promoting the cerebral specialization necessary for developing a skilled preferred hand. Moreover, several authors have suggested the inclusion of bilateral coordination and midline crossing activities when treating unestablished handedness in pediatric occupational therapy practice (Clancy & Clark, 1990; Knickerbocker, 1980; Levine, 1991; Stephens & Pratt, 1989; Whitehead, 1978; Wilson, 1994). In some instances mention is made to “remind” a child to use the preferred hand when hand use is inconsistent (Koomar & Bundy, 1991), although this presupposes a certainty about the child‘s “correct” handedness or hand dominance. Unfortunately, empirical evidence is lacking to support the therapeutic effectiveness using any of these treatment strategies in promoting handedness establishment. A sensorimotor and sensory integrative approach to treatment of a 3- to 4-year-old child with unestablished
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handedness seems appropriate, because an overall development of laterality may well assist in establishing handedness. However, older children presenting with unestablished handedness pose the greatest challenge, particularly so if a decision on handedness is eminent because of school entry. Based on the current handedness knowledge discussed so far, assessment results should be analyzed carefully before embarking on clinical decision making. How do we know if a child is inherently left or right handed? Are there other factors to consider before making a final decision? What is the most beneficial treatment for that child? In her doctoral thesis, Kraus (2003) methodically evaluated existing handedness measures, proposed several different reasons why children could present with unestablished handedness (or types of variable handedness), devised a novel assessment battery and suggest treatment guidelines in the context of her Handedness Profile. This process could be one way to deal with these questions, but it extends beyond the scope of this chapter. In the absence of evidence-based practice to substantiate certain treatment approaches, differential handedness assessment methods are crucial.
Switched Handedness When addressing switched handedness flag a note of caution. Although many of a child’s presenting problems might be related to, or caused by, switched handedness (Fischl, 1986; Friedman, 1987; Harris, 1990; Olsson & Rett, 1989; Richberg, 1987; Sattler, 1998; Stutte et al., 1977), “unswitching” might not be favorable in every case because there appear to be certain preconditions for successful handedness retraining. According to Sattler (1998), these preconditions include the following: (a) full support for the retraining process of parents and teachers; (b) a relatively stressfree situation with flexible time constraints on writing, and limited writing volume; (c) sufficient motivation of the child; and (d) a skilled therapist experienced with handedness issues. In addition, based on my own clinical experience as an occupational therapist, average or above-average motor performance level of the left hand, regular occupational therapy sessions, monitoring of progress, and regular follow-up (including close contact with parents and teachers), also are necessary for a successful handedness retraining outcome. Age does not appear to be a major factor for successful retraining because numerous case studies exist of adult switched handers who have successfully retrained their original or dominant handedness (Sattler, 1998). A case study, based on the Handedness Profile (Kraus, 2003), illustrates the clinical decision making process for a child with switched handedness (Box 9-4). However, a note of caution: Until therapists are more familiar with the dynamics and associated
problems of unestablished or variable handedness, they should refrain from retraining handedness, unless they receive professional supervision or have completed special courses in this field.
Left Handedness In most aspects, there are no differences between treating left and right handed children in therapy, because motor problems are common in both groups and should be treated according to the same principles. However, two intervention areas require specific attention for left handers: writing and those ADL activities that involve utensils designed for right handers. Writing The act of writing from the left to the right is conducive to right handers, who engage in a pulling motion across the page whereby the written work is clearly visible. Left handers have to adhere to the same left-to-right direction in writing and thus should apply a pushing motion that is more difficult to control. Furthermore, if left handers employ the mirror image hand position of right handers during writing, the left hand obscures the written work, and if a fountain pen is used, smudges it. The pushing action and visual limitations seem to be the main reasons why many left handers develop compensatory positions that often result in an unfavorable, cramped writing grasp with wrist flexion. Although the pushing action may be more laborious when learning to write, this is no reason to switch a left-handed child to right-handed writing, because there is evidence that left handers are able to develop the same writing speed as right handers (Sattler, 2001). However, if a child learns to use a hooked or clawed writing position through compensation, this is more likely to impede on the speed, legibility, and ergonomics of writing. In therapy it is thus crucial to establish the correct writing pattern for left handers. The basic principles are the same as in right handers: • 90°-90°-90° position at hips, knees, and feet, with table height two fingers above the adducted elbow; good upright posture • The upper arm only abducts slightly when the forearm moves outward to the side, and the elbow does not protrude sideways • Lateral support of the ulnar side of the hand and wrist extension • Refined and relaxed tripod grip enabling intrinsic finger movement The following principles are specific to left-handed writing: • Paper or exercise book placed slightly toward the left of the body midline with the left top corner slanted between 20° and 40° up to the left
Handedness in Children • 183 BOX 9-4
Case Presentation of “Tim” as an Example of Clinical Decision Making Based on Background Information, the Handedness Profile (Kraus, 2003)
BACKGROUND INFORMATION Tim (6 years and 6 months old) presents with righthanded writing. A history of early left hand use is reported, and both father and sister are self-reported switched left handers. There are indications of sociocultural pressure for right hand use, with Tim’s father openly advocating the need to switch left handedness to right handedness. There is a history of birth-related stress and general mild developmental delay. HANDEDNESS PROFILE • Untrained hand preference tasks: More left than right responses, below average performance, inconsistent within and across tasks • Trained hand preference tasks: Slightly more right than left responses, below-average performance, inconsistent across tasks mainly • Hand performance ability: Significantly more right than left responses, average performance • Hand performance skill: Significantly more right than left responses, below average performance • Midline crossing: Crosses more frequently with the left but overall avoids contralateral reaching • Simple bimanual coordination (bimanual circle drawing): Leads more with the left, average performance • Overall classification: Variable left hander DISCUSSION AND INTERPRETATION OF RESULTS The handedness profile indicates both within-task and across-task inconsistency, in which the left hand is used more for untrained tasks (mild left) and the right slightly more for trained tasks (variable right). There was no
• In general, wrist extension can be greater than in right handers; that is, closer to maximum extension (and not closer to neutral, as in right handers). This allows the writing hand to be placed below the written work and thereby ensures good visibility as well as a functional and refined pencil grasp. In practice, wrist extension might be closer to neutral when starting to write from the left side, and may increase as the hand moves toward midline. Mirror writing or reversals is another interesting aspect often observed with left-handed writing. There seem to be two reasons for this. First, there appears to be a natural tendency for a pulling motion during drawing and writing, which, for left handers, extends from right to left. Second, there is evidence that right handers tend to process visual information in a left-toright direction, whereas left handers process in the opposite right-to-left direction (Sattler, 1998). These tendencies may result in reversals but do not necessarily presuppose problems, unless the child also has visual perceptual processing problems. It is a matter of practice and habit to adopt the left-to-right visuomotor
incongruence between ability and skill, because the right hand performed notably better than the left in both ability and skill. For midline crossing the left hand was used more for contralateral reaching than the right, although Tim generally avoided crossing the midline. Ability was performed in the average range with the right hand, which is not unusual for left handers as a group. However, skill was performed better with the right than with the left hand but scored in the poor range. This might result from a mild motor-based deficit, because both hands performed in the subaverage or poor performance level range despite the practice effect of the right hand. Bimanual coordination was scored in the average range with a stronger left-handed lead. This, together with average ability performance, suggests an absence of severe coordination problems. In the light of sociocultural pressure for right hand use, it can be assumed with reasonable confidence that switched handedness is responsible for Tim’s variable hand use. CLINICAL DECISION MAKING It appears that Tim’s motor and perceptual problems have a developmental basis, and it is likely that these problems are exacerbated by his switched handedness. However, considering that his left hand performed in the subaverage range for the “nonpreferred” hand, and given the “proswitching” attitude prevalent in his family, the option of retraining handedness was rejected. Instead, a sensorimotor program addressing his gross motor problems, and a graded fine motor and graphomotor program appeared more appropriate.
processing direction, but left-handed children might thus undergo a more extensive phase of reversals and mirror writing. Activities of Daily Living Although many activities of daily living (ADL) tasks can be performed by left handers in a mirrorlike fashion to right handers (e.g., brushing teeth, getting dressed, doing buttons, tying laces), there are several ADL tasks that involve utensils with a right-handed bias, or that are performed in a right-hand-biased environment. These include cutting with scissors and one-sided bladed knives, pencil sharpeners, computer mice with clicks for the right index finger, playing the piano (with the more difficult part usually on the right), reading and using measuring jugs, tightening of screws with a screwdriver, and opening lids and taps with external wrist rotation that usually require greater strength. Clearly, there are differences in proficiency levels involved in these tasks, and many left handers quite easily learn to perform low-level skill tasks with their right hand. For higher skill levels, such as cutting with scissors, it is
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advisable to provide left-handed scissors. (Incidentally, the so-called two-bladed scissors that are advertised for both left and right handers may have a good cutting action, but vision is obscured for left handers because the scissor blades are assembled for right handers.) However, if a left-handed child has already taught herself or himself to cut with good results with the right hand, and if he or she resists changing to the left, this is usually in order. If a left-handed child experiences difficulties in other ADL tasks, there are several shops for left handers advertised on the internet, in which information on left handers is available and equipment and utensils can be ordered (e.g.,
[email protected];
[email protected]).
CONCLUDING REMARKS Considering the complexity of handedness, it seems unlikely that there is one standard treatment approach that could effectively enhance the establishment of handedness, or that a certain combination of approaches is effective in all cases. Although the appropriateness and effectiveness of these treatment approaches in addressing unestablished handedness has still to be determined, it is proposed that the therapist should be familiar with different types of intervention, applying one or more approaches as deemed most beneficial to each individual child. Furthermore, the development of handedness, in relation to the development of midline crossing and bimanual coordination, provides valuable guidelines for therapy.
SUMMARY This chapter has demonstrated that handedness is a variable, complex, interactive, and multidimensional phenomenon subject to hereditary, environmental, and social influences. To understand and assess handedness not only in this context but also in terms of function within occupational performance, those behaviors closely linked to handedness, function, and environment (i.e., bimanual coordination and midline crossing) should be assessed. The development, publication, and standardization of a comprehensive handedness assessment tool that satisfies these criteria is still pending, as is the analysis of the results for clinical decision making. A comprehensive assessment procedure is a crucial research tool for investigating the nature of unestablished, left and right handedness as well as the effectiveness of different treatment approaches. It can be concluded that handedness is a pediatric specialist area in occupational therapy that is in need of much empirical evidence and support.
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SELF-CARE AND HAND SKILL Anne Henderson
CHAPTER OUTLINE IMPORTANCE OF INDEPENDENCE IN SELF-CARE Importance to the Child Self-Care in Disability MEASUREMENT Nonstandardized Measures Standardized Instruments FACTORS IN THE ACQUISITION OF SELF-CARE Social and Cultural Influences Sex Differences Maturation Mastery Motivation Motor Factors CHRONOLOGY OF SELF-CARE ACQUISITION Eating Dressing Hygiene and Grooming DISCUSSION Hand Skills in Self-Care Perceptual Factors in Self-Care Cognitive and Personality Factors in Self-Care SUMMARY
The performance of self-care activities is so universal that its relevance to all aspects of living is often overlooked. Eisen and co-workers (1980) in their Health Insurance Study conceptualized child health as including physical, mental, and social health. They defined physical health in terms of functional status, which in turn was defined as the “capacity to perform a variety of
activities that are normal for an individual in good health” (p. 7). Thus they considered self-care performance to be a critical aspect of the health and wellbeing of a child, and included the categories of eating, dressing, bathing, and toileting. These are the basic activities of self-care. They, with the inclusion of grooming and hygiene, are the subject of this chapter. We recognize the equal importance in the health of the individual all the functional status activities identified in this chapter as basic, as well as those identified as activities of daily living (ADL) and independent activities of daily living (IADL) skills or self-maintenance skills (American Occupational Therapy Association, 1994). However, it is independence in basic self-care that usually is achieved in childhood. The child entering school is expected to be toilet trained and self-sufficient in eating, dressing, hygiene, and simple domestic tasks. These self-care activities are among the first achievements of childhood, and they provide independence, social approval, and a sense of mastery for the child. This acquisition of self-care skills in childhood is intricately involved with the development of motor skill. The motor skills discussed in this chapter are limited to those of the hand. We recognize that postural control is essential for all self-care and oral–motor control is essential for eating and refer the reader to several excellent discussions of their role in basic self-care (Case-Smith, 2000; Shepard, 2001). The reader must also incorporate the information in this chapter into an overall framework of physical, mental, and social development. The purpose of this chapter is to review what is known about the development of self-care in relation to the development of hand function. We begin with comments on the importance of self-care, its measurement, and on factors such as culture and personality that influence its development. We then present a developmental overview of eating, dressing, and hygiene and grooming behavior and end with a discussion of
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hand skills and other factors affecting the achievement of particular skills.
of volitional behavior (Bullock & Lutkenhaus, 1988). Volition implies action in which the achievement of a goal is seen as resulting from one’s own activity.
IMPORTANCE OF INDEPENDENCE IN SELF-CARE
SELF-CARE IN DISABILITY
Children of every society are expected to develop independence in their performance of everyday living skills and in most cultures independence is taken for granted as children reach the appropriate maturational levels. The universal expectation for competence in selfcare activities is the reason for the emphasis on their acquisition in rehabilitation and education.
I MPORTANCE TO THE C HILD A child’s control over the environment comes to a large degree through mastery of daily activities (Amato & Ochiltree, 1986). The ability to feed, dress, and care for toileting needs significantly increases a child’s control over both home and school environments. For example, a child who dresses himself or herself does not have to depend on the convenience of the caregiver. The child has more control of time, to be dressed without waiting, or delay dressing a bit to complete an interesting activity. The ability to meet individual needs without seeking help can result in feelings of efficacy and control (White, 1959) and this is a most important consideration in the development of basic self-care. Selfdependence is an important developmental task in any culture, the achievement of which wins cultural approval, and cultural pressures are such that mastery of a given task leads to satisfaction. Furthermore, teaching self-care activities provides an opportunity for caregivers to instill positive self-esteem in young children. The observation of emerging independence in a child has been called “an early joy of parenthood” (Coley & Procter, 1989, p. 260). In the United States children are encouraged and praised for self-sufficiency, with the result that most want to be independent and feel a sense of pride in mastery (Gordon, 1992). Young children often announce achievements such as tying a bow or buckling a shoe to family and friends, often wanting to demonstrate their new skill. When parents actively encourage and teach children to care for themselves, they are fostering the development of competence (Maccoby, 1980). Furthermore, young children demand independence: “I can do it myself.” This insistence on self-sufficiency in performing activities begins during the second year of life (Geppert & Kuster, 1983) and has been related to the development
The timely achievement of abilities in self-care tasks is important in the daily life of all children in the US culture and the inability to perform a skill is a major barrier to school and home living for children with special needs. In the development of a child’s potential “acquiring daily living skills may be as important as academic qualifications” (Gordon, 1992, p. 97).
The degree of disability in self-care among children with special needs varies with type and degree of impairment both within and among disabilities. In a London school district a survey conducted of special needs children (primarily with cerebral palsy or multiple handicaps) reported that about 65% needed help in dressing and 25% in eating (Inglis, 1990). A study of young adults with cerebral palsy also reported a high degree of continuing dependence: Fewer than half were independent in basic self-care (Senft et al., 1990). As expected, these researchers found a greater degree of dependence in persons with quadriplegia: The majority of persons with hemiplegia were independent. Another study of young persons with hemiplegic cerebral palsy found most had achieved mastery in self-care, including the bimanual activities, but some expressed reluctance to perform them because the adaptive method made them look different (Skold, Josephson, & Eliasson, 2004). Children with developmental coordination disorder usually are evaluated for achievement in drawing, writing, and schoolwork. Less attention has been given to their self-care needs, but descriptive studies have shown that their impaired motor abilities sometimes interfere with eating and dressing independence (Gubbay, 1975; May-Benson, Ingolia, & Koomar, 2002; Walton, Ellis, & Court, 1962). The possible delay in self-care acquisition is now considered one criterion for diagnosis of the disorder (American Psychiatric Association, 1994; Cermak & Larkin, 2002). Many disabilities of childhood interrupt the typical sequence of independent performance in self-care skills. Their importance in early childhood in the presence of a disability sometimes is underestimated because infants and preschool children are naturally dependent and easy to tend. Parents may not be too concerned about delays in activities such as dressing, but as a child grows and siblings are born, extended dependency can add significantly to the stress within a household (Wallander, Pitt, & Mellins, 1990).
Self-Care and Hand Skill • 195 Research has demonstrated that life outcomes in social and work situations of young adults with congenital handicaps appear to be related to their independence in self-care. For example, Wacker and co-workers (1983) reported that the variables most strongly related to satisfaction with life outcomes were the individuals’ perception of their independence in self-care and mobility. Christiansen (2000) has noted that being able to conform to societal expectations for self-care is integral to overall feelings of life satisfaction. Self-dependence in everyday tasks is important to everyone, and no less so for children whose achievement is interrupted by disability
MEASUREMENT NONSTANDARDIZED M EASURES Since the early years of the profession, therapists have been concerned with the assessment and treatment of dysfunctional self-care performance. One of the first known checklists of self-care performance was published in 1935 (Wolf, 1969); since that time assessment of function has been traditional in both occupational and physical therapy. Assessment forms were published from time to time in the early years, but more often treatment settings designed forms to meet the needs of their particular caseloads and treatment settings. Developmentally oriented functional assessments that incorporated information on child growth and development came into use in the 1940s, and developmental scales that included basic self-care were published a few years later. For example, an upperextremity motor development test that included agekeyed items on feeding, dressing, and grooming, as well as hand use, was developed at the New York State Rehabilitation Hospital (Miller et al., 1955). Such instruments used information on ages at which children typically master skills, and grouped the skills by the age at which achievement might be expected. One of the reasons therapists have continued to construct their own instruments is because of the need for greater detail in planning treatment programs for different disabilities. Breakdown of self-care activities is different for a child with a congenital amputation, cerebral palsy, spina bifida, or mental retardation. Both center-made and published scales are designed for dayby-day guidance of intervention and are as detailed as available knowledge allows. Some published nonstandardized instruments have been designed for specific disability areas. For example, a comprehensive tool for evaluating children’s self-sufficiency in self-care activities was developed by the Occupational Therapy Department at Children’s Hospital at Stanford,
California (Bleck & Nagle, 1975; Coley, 1978) primarily for use in cerebral palsy patients. Developmental scales providing standardized administration and some reliability of scoring also have been published (Brigance, 1978; Vulpe, 1979). The estimated ages at which the tasks and subtasks are accomplished are derived from multiple sources that are identified in the manuals. Sources include intelligence tests, developmental tests, and research studies. Because these tools were intended as a guide for the sequential learning of self-care and other developmental skills, they include multiple steps in achievement. The purpose of these assessments is to provide an intervention guide and an ongoing inventory of a child’s progress and achievements in all developmental areas. The developmental assessment published by Vulpe has a particularly detailed section on self-care. Published and unpublished center-made measures such as those described have been in wide use. The advantage of center-made instruments is that they can be designed for the needs of particular children in particular settings. The disadvantage is that assessment information cannot be generalized to other disabilities or settings and the semiformal methods of administration make it difficult to ensure reliability among different therapists, even when a standardized method of evaluating each item has been developed. Change in a child’s skill or the lack thereof might reflect differences between therapists rather than changes in performance.
STANDARDIZED I NSTRUMENTS Derived normative age information for developmental scales is at best only fairly accurate, and the information on individual children is descriptive only. Meaningful overall scores are not obtainable because there is no way of weighing individual items. Therefore they are not appropriate for use in research or the documentation of overall progress. Two pediatric assessments designed for the functional evaluation of children with disabilities and the reliable documentation of change were developed and standardized in the 1990s and are now in wide use in the United States, as well as in other countries. They are the Wee Functional Independence Measure (WeeFim) (State University of New York at Buffalo, 1994) and the Pediatric Evaluation of Disability Inventory (PEDI) (Haley et al., 1992). Both include sections on basic self-care and have been demonstrated to be valid and reliable (Ottenbacher et al., 2000). The two instruments are highly correlated (Ziviani et al., 2001): Each has its advantages. The PEDI gives more depth of information but the WeeFim is easier and faster to administer.
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The WeeFim evaluates functional independence of children ranging in age from 6 months to 7 years and is simple and fast to administer. Seven of the 18 items are self-care and the scale yields a single score for the level of independence in each of the domains of eating, grooming, bathing, dressing upper body, dressing lower body, and toileting. The instrument is being validated in other countries; for example, in Japan (Liu et al., 1998; Tsuji et al., 1999) and China (Wong et al., 2002). The PEDI evaluates self-care, mobility, and social function in much greater detail than the WeeFim. The items in basic self-care provide considerable information on a child’s abilities and include the following areas: eating different food textures; use of utensils; use of drinking containers; tooth brushing; hair brushing; nose care; hand washing; washing body and face; pullover/front opening garment; fasteners, pants, shoes/socks; and toileting tasks. The PEDI has several strengths as a measurement tool for children. It has been carefully standardized and yields a total score that can be used to measure the overall progress of children with disabilities. Age expectations are given both for overall independence in separate domains and individual items. The user can select the level of expectation desired, such as the age range at which 10%, 25%, 50%, 75%, or 90% of children without disabilities demonstrate mastery. The PEDI has been validated for use in other cultures, including Puerto Rico (Gannotti & Cruz, 2001). Research has shown that the PEDI can be used to document gain in self-care (Dumas et al., 2001). In summary, the selection of a measurement tool needs to be based on the major purpose of the tool. If multiple purposes are to be met, more than one tool should be used. Possible purposes are (a) diagnosticremedial, that is, to provide a blueprint for selecting and sequencing treatment activities; (b) description of self-care performance for communication with parents and professionals; (c) charting the acquisition of selfcare skills; and (d) evaluating the effects of treatment. Both center-made and published but not standardized evaluation instruments can be used for the first three purposes; only standardized instruments are appropriate for the fourth.
FACTORS IN THE ACQUISITION OF SELF-CARE Our knowledge of the factors that influence the development of basic self-care is based more on common knowledge derived from the experience of caregivers than on research. However, most agree with the state-
ment made by Key and co-workers (1936) about dressing; that learning is influenced by chronological age, mental age, the child’s interest, the amount of guidance given, and the type of clothing worn. Whether or not these factors are supported by research, social, psychological, and physical factors, as well as gender and maturation, clearly play a part in skill acquisition.
SOCIAL AND C ULTURAL I NFLUENCES Gesell and Ilg (1943) considered the development of feeding behavior in the infant to be a “story of progressive self dependence combined with cultural conformance” (p. 317).
The broad culture and expectations of the home and preschool all determine the degree and timing of a child’s mastery of basic self-care skills. With the development and standardization of selfcare instruments in the United States, researchers in other countries have conducted studies to determine whether the measures can be used in their populations (Gannotti & Cruz, 2001; Wong et al., 2002). Studies also have provided information about differences between countries in ages of self-care acquisition. For example, younger Chinese children scored better than U.S. children in self-care on the WeeFim (Wong et al., 2002) and Puerto Rican children developed some self-care skills later (Gannotti & Handwerker, 2002). The timing of the mastery of self-care activities depends on the expectations for the child and these expectations differ among cultures. The U.S. culture places high value on self-sufficiency, so that childrearing practices emphasize early independence. Many other cultures place a higher value on family interdependence, for example, in Puerto Rico child-rearing practices include later teaching of skills such as selffeeding (Gannotti & Handwerker, 2002). An obvious cultural factor is in the difference in food practices. In India food is eaten with the hand; in the United States utensils are used, and in Asian countries children use chopsticks. These three methods of selffeeding require different hand skills. Hand feeding requires less motor maturation than the use of a spoon, which in turn requires less motor maturation than chopsticks. The spoon is grasped in the fist and can be carried to the mouth with the forearm pronated and the arm abducted, but chopsticks require individuation of the fingers and supination of the forearm. Another difference is the way in which knives and forks are used. In the United States, one scoops and spears with a fork and cuts meat with the knife in the right hand, then
Self-Care and Hand Skill • 197 switches utensils to continue eating. In some European countries the knife is used in the right hand to pile food on the back of the fork, which is then carried to the mouth with the left hand. These differences may influence the sequence and timing of self-sufficiency in self-feeding. Differences in dressing styles must certainly influence skill attainment. In some cultures children go naked until they are toilet trained. In the United States the emphasis on early self-sufficiency has led to inventions in clothing style. For example, draw-down diapers foster an earlier independence in going to the toilet, and Velcro fasteners make the preschool child selfsufficient in putting on shoes and outer clothing. Individual families also influence the performance of everyday skills. In this author’s experience in Mexico, many families with maids did not permit children to use spoons until they were able to do so without spilling; bibs were not used beyond early infancy. Wong and coworkers (2002) also reported that the presence of a maid in the home led to later achievement of self-care. Another example of family influence is on a child’s tidiness in eating. Bott and co-workers (1928) wondered why a child who was above average on most measures was so far below age expectations in eating. On questioning the parents they discovered that, because they thought the child was too young to eat well, they had made no attempt to correct him. When the expectations for the child were raised at home, his score rose to age levels within 2 weeks. Such differences in attitudes result in differences in the timing of the child’s mastery of basic skills. Two studies have investigated family factors influencing competence in household tasks. A study by Zill and Peterson (cited by Amato & Ochiltree, 1986) found that the best predictor of performance on tasks such as washing dishes without help was the frequency of joint family activities. They also found that family size was related to competence in such skills. Large families may require more practical assistance from their children in chores, and younger children are able to learn from older children. The family variables found by Amato and Ochiltree (1986) to foster the acquisition of practical skills were frequent interaction of family members and the requirement that the children take responsibility for chores. In summary, cultural, class, and family variables influence the timing of the acquisition of independence in self-care in young children. For the most part societal expectations do not vary in respect to the need for eventual development of independence, but behavior in childhood may signify cultural and parental patterns rather than a child’s intrinsic abilities. Awareness of such patterns is important in assessment and goal setting.
SEX DIFFERENCES Early literature reported several differences between girls and boys in the age at which self-care skills are acquired. Gesell and Ilg (1943) wrote that boys demand independence in dressing at a younger age than girls. Key and co-workers (1936) reported tentative sex differences in dressing ability between 21⁄2 years and 41⁄2. Girls were more skillful than boys and tended to dress faster, and the ability of boys generally was more variable than that of girls. Sources of the differences in the ages at which dressing skills are achieved have been proposed. It has been thought that girls dress themselves earlier than boys because their wrists are more flexible, they are better coordinated, and they wear simpler clothing (Coley, 1978; Gesell et al., 1940; Key et al., 1936). A difference also has been reported in the use of eating utensils in self-feeding (Gesell & Ilg, 1943). Girls shifted to an adult grasp earlier than boys, some as early as 3 years. Some boys, on the other hand, continued to use a pronated grasp at 8 years of age. Boys also were reported to sometimes demand to feed themselves before they were competent to do so. One recent study has also shown a difference between the sexes. In China, younger girls were reported to score higher than boys on the self-care subscores of the WeeFim (Wong et al., 2002). However, no sex differences in overall functional ability were found in research in the United States on the PEDI (Haley et al., 1992).
MATURATION Although culture and family expectations play a role, it seems clear that the greatest factor in the achievement of self-care skill in childhood is maturation. Certainly Gesell and his associates thought so, and self-care items are prominent in his developmental diagnosis (Gesell & Amatruda, 1965). This supposition was borne out by the research of Key and her associates (1936), who found the correlation between dressing ability and chronological age to be considerably higher than that for mental age or any other factor. Furthermore, the composite score of self-care, mobility, and social functions of the PEDI showed high and significant correlation with age but not with demographic variables.
MASTERY MOTIVATION The concept of mastery motivation has its roots in the writings of Robert White (1959), who proposed that the development of competence in young children grew out of a pleasurable sense of efficacy when they successfully manipulated objects. The toddler and
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preschool years are important periods in this development of goal-oriented behavior, and wanting to be self-sufficient in the performance of early eating and dressing skills is one expression of effectance or mastery motivation (Bullock & Lutkenhaus, 1988; Geppert & Kuster, 1983). Early anecdotal accounts of achievement in self-care performance indicated that interest, self-reliance, and perseverance were important attributes. Wagoner and Armstrong (1928) found success on a buttoning task was correlated with teacher ratings of perseverance. Key and her associates (1936) reported that interest in dressing develops with ability in 2-yearold children and that enjoyment increased as mastery improved. However, at 3 years they found that interest shifted to desire for approval and achievement and also found wide differences among the children in the development of self-reliance and the perseverance needed for the performance of the more difficult tasks. These findings were based on analysis of the children’s comments while they were dressing. Recent studies in mastery motivation have focused on its relationship to many different child factors such as cognition (Hauser-Cram et al., 2001) and parent factors such as negative and positive maternal behaviors (Kelley, Brownell, & Campbell, 2000). These recent studies measure mastery motivation in a test situation, usually with puzzles graded in difficulty so that they provide a challenge for the level of each child. A longitudinal study of particular interest for this chapter showed that children with disability who scored higher levels of mastery motivation at 3 years of age achieved greater independence in self-care at 10 years (HauserCram et al., 2001). These researchers found mastery motivation to be important both for the development of a child and for the well-being of the parent.
MOTOR FACTORS Coley (1978) identified sequences of gross and fine motor development leading to independence in selfcare tasks. Examples of necessary gross motor abilities needed for dressing are reaching above the head or behind the back while maintaining trunk stability. Selffeeding requires head and mouth control, as well as trunk stability. Coley identified steps in the motor control leading to many individual self-care skills, and they are discussed within each self-care domain. They include bilateral skills, finger manipulation, and tool skills. Children learn one-handed skills before bilateral skills, and some skills are achieved later because of the need for the two hands to work together. An early example is holding a bowl with one hand while scooping with the other. Children become functional in the performance of skills during their preschool years, but complete independence and adult levels of
speed and precision require a long developmental period. One indication of the automatization of a skill that occurs at about 4 years of age is when children can feed and dress themselves while carrying on a conversation (Hurlock, 1964; Klein, 1983). Many self-care activities require the use of tools (Castle, 1985). Tools are defined here as a means of effecting change in other objects. The earliest self-care tools are for eating: spoons, knives, forks, and cups. Self-care in hygiene includes tools such as brushes, combs, and washcloths. Dressing fasteners, zippers, snaps, and buttons also can be considered tools. The use of most tools is complex because it involves the manipulation of one object relative to another, which results in the change of state of one or both objects (Parker & Gibson, 1977). The use of tools is goal directed by definition and requires the understanding of a means–end relationship. Even the use of a simple tool such as a spoon requires both the understanding of purpose and the motor skill to use it. However, as children mature, their understanding often moves ahead of their manipulative skill. In general, learning to use tools is acquired later than self-care without tools.
CHRONOLOGY OF SELF-CARE ACQUISITION The following pages present developmental patterns and the ranges of ages in which typical children learn to care for their own daily needs. This information is presented as a summary of what is currently known about the chronology of the acquisition of skill in selfcare as a source for the understanding of the process by which skills are acquired. The immediate purpose is to allow a preliminary analysis of the relationship of the acquisition of self-care skills to the development of hand skills. The information that follows has been compiled from different sources to provide as much detailed information as possible. The child’s attempts at performance are included because they show an understanding of the task, and the practicing of subskills reflects motor abilities. The developmental information in the following discussion is organized into the domains of eating, drinking, dressing, personal hygiene, grooming, and simple household tasks. The items listed in the charts are steps in the learning of self-care that various authors have observed and reported. We have no definitive information as to the universal consistency of the sequences presented: They are based on reports of ages at which children are usually self-sufficient in discrete skills. The area of research that has provided the most information on the acquisition of specific self-care skills
Self-Care and Hand Skill • 199 over the years has been the area of development of evaluation tools. Two such primary sources of information were used to chart the general ages at which skills are achieved. The first source is the PEDI (Haley et al., 1992). As has been noted, this instrument includes extensive sections on basic self-care and provides the most reliable information available on the ages at which many skills are achieved. The ages noted in the tables from the PEDI indicate a group in which more than 75% of the children were reported to have achieved independence. The works of Gesell and his associates also were a primary source. Data on the ages at which children developed specific self-care skills were collected by many different methods over many years. The results of most of their observations were incorporated into overviews of development (Gesell & Amatruda, 1965; Gesell & Ilg, 1943, 1946; Gesell et al., 1940). They were interested in information that would assist in the diagnosis of developmental delay and to that end selected different sorts of behaviors expected at each age level. The behaviors selected have provided information on the acquisition of basic self-care skills for many years. Several secondary sources also were used. Following the lead of the Yale Developmental Clinic, self-care items were and continue to be included in many developmental evaluations. The primary and secondary sources used for the tables were Coley (1978), Brigance (1978), Vulpe (1979), Haley and co-workers (1992), Gesell and Ilg (1943, 1946), and Key and coworkers (1936). It must be emphasized that the ages listed from these sources are only approximate, are not necessarily derived the same way, and reflect different levels of expectations. As has been noted, family, social, and cultural values influence expectations for independence in self-care skills and these expectations result in individual differences in skill acquisition. Furthermore, it must be recognized that even within a homogeneous group the age at which children master self-care skills is highly variable. An important finding of the PEDI research was that there is a wide age range, sometimes as much as 3 to 4 years, over which individual children achieve a particular skill. A recent study of the development of feeding behaviors also found a wide range of ages at which self-feeding skills occur (Carruth & Skinner, 2002). The data in the following tables are best interpreted as the age range at which many, but not all, typical children in the United States perform under optimum circumstances.
EATING The progress of a child’s self-feeding behavior requires both the acquisition of skill in the use of eating utensils
and conformity to cultural standards. In typically picturesque speech, Gesell and Ilg (1943) described this progression: “At 36 weeks he can usually maintain a sustained hold on the bottle. In another month he may hold it up and tilt it with the skill of a cornetist. He can feed himself a cracker. At 40 weeks, he also begins to finger feed, plucking small morsels. … He also handles his spoon manfully [by 15 months] and begins to feed himself in part, though not without spilling, for the spoon is a complex tool and he has not acquired the postural orientations and pre-perceptions necessary for dexterity. … At 2 years, he inhibits the turning of the spoon as it enters the mouth and feeds himself acceptably. … At 31⁄2 years he enjoys a Sunday breakfast with the family. … At 5 years … he likes to eat away from home especially at a restaurant. He is more a man of the world!” (pp. 318–319).
Finger feeding and the use of a cup are early accomplishments and the basic components of selffeeding with a spoon—filling the spoon, carrying it to the mouth without spilling, and removing food—are well mastered by 3 years of age. However, self-feeding takes concentration, and it is not until after the third or fourth year that the skill is sufficiently automatic to allow eating and talking at the same time (Hurlock, 1964). The 5-year-old is skillful but slow. Skill continues to improve, for it is not until 8 or 9 years of age that the child has become deft and graceful (Gesell & Ilg, 1946), and it is not until 10 years that self-feeding is accomplished entirely independently, with good control and attention to table manners (Hurlock, 1964).
Finger Feeding Self-feeding with the fingers begins in the second half of the first year. Table 10-1 shows the development of the skill, which parallels the infant’s acquisition of hand skills. Initial feeding is of crackers held in the hand and sometimes plastered against the mouth with the palm and with the forearm supinated. As finger skill develops, bite-size pieces of food are picked up and put into the mouth with a pincer grasp. Even when spoon use has become skillful, children prefer to use fingers for discrete pieces of food such as peas or meat (Gesell & Ilg, 1943).
Drinking from a Cup or Bottle Independent drinking from a cup is an early developing skill as long as safeguards are taken. The use of spout cups with lids allows a child to drink from a cup, as well as a bottle in the second half of the first year of life. Table 10-2 shows the progress of skill in drinking. Cup drinking begins with the same bilateral whole hand grasp used for the bottle and progresses to the dexterous grip of one hand on the handle at 3 years of age.
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Table 10-1
Eating finger foods
Skill
Age
Source
Picks up finger foods and eats
6 mo–1 yr
Haley et al. (1992)
Feeds self cracker, whole hand grasp
6–7 mo
Coley (1978)
Feeds self spilled bits from tray
9 mo
Gesell and Ilg (1943)
Feeds self finger foods, pincer grasp
10 mo
Coley (1978)
Finger feeds part of one meal
1 yr
Gesell and Ilg (1943)
Takes bite-size pieces from plate, delicate grasp, appropriate force, with demonstrated release
1 yr
Coley (1978)
Table 10-2
Self-feeding: drinking from cup or bottle
Skill
Age
Source
Holds and drinks from bottle or spout cup with lid
6 mo–l yr
Haley et al. (1992)
Tips bottle to drink
10 mo
Gesell and Ilg (1943)
Lifts open cup to drink, some tipping
11⁄2–2 yr
Haley et al. (1992)
Holds cup alone, hands pressed on side
1 yr
Gesell and Ilg (1943)
Grasps with thumb and fingertips
1 yr 3 mo
Gesell and Ilg (1943)
Holds cup and tilts by finger action
1 yr 3 mo
Gesell and Ilg (1943)
Lifts open cup securely with two hands
11⁄2–2 yr
Haley et al. (1992)
Lifts cup to mouth, drinks well, may drop
11⁄2 yr
Coley (1978)
Holds cup well, lifts, drinks, replaces
1 yr 9 mo
Coley (1978)
Holds cup or glass with one hand, free hand poised to help
2 yr
Gesell and Ilg (1943)
Lifts open cup to drink with one hand
3–31⁄2 yr
Haley et al. (1992)
Cup held by handle, drinks securely, one hand
3 yr
Gesell and Ilg (1943)
Self-Care and Hand Skill • 201
Use of Utensils Table 10-3 shows the chronology of the development of the use of spoons, forks, and knives. The many years necessary for learning to use utensils reflects the complexity of their use, particularly the knife and fork in cutting. The infant begins eating with a spoon held in a fisted grasp, with the arm pronated and shoulder abducted. The adult finger grip, with forearm supination and rotation as needed, requires more fine motor control and dexterity (Haley et al., 1992) but does not develop until approximately 3 years in girls (Gesell et al., 1940); some boys continue to use a pronated pattern at 8 years (Gesell & Ilg, 1946). The fisted grasp appears again in the use of forks and knives in cutting. It appears that the force needed for holding and cutting requires the power of the whole hand and the necessary power combined with the finger dexterity for cutting is not developed until a child is about 10 years old. Studies of Spoon Use The spoon is the first tool used by most infants (Connolly & Dalgleish, 1989). Several studies of spoon use have been reported, two involving infants and one preschool children. The earliest study was of nursery school children’s eating behavior (Bott et al., 1928). The eating behaviors included in the study were (a) the proper use of utensils, (b) putting the proper portion of food on a utensil, and (c) coordination, as indicated by minimal spilling. They found improvement with age in all these behaviors, but the behaviors differed as to when they improved. The use and filling of the utensils improved primarily between 2 and 3 years of age, but spilling decreased more between 3 and 4 years. A cinemagraphic study of infant eating behavior conducted by Gesell and Ilg (1937) described both prespoon activity and early spoon use. Preparation for using the spoon began when a child was being fed. Between 3 and 6 months of age the child watched the spoon, and soon mouth opening began in anticipation of the spoon reaching the mouth. Later, head movements began with movement of the head toward the spoon and then away as food was removed. Whereas initially food was put in the mouth by the adult’s manipulation of the spoon, the child later removed food by lip compression. These movements of the head and lips were considered to make later spoon manipulation more effective. Gesell and Ilg noted that even as simple a tool as a spoon requires a sequence of perceptual and motor acts. One act is the discriminative grasp of the spoon handle. Infants first grasped the lower third of the handle, later the middle to upper third, and finally the end. Grasp was at first palmar, with the thumb wrapped around the spoon, but later the thumb was placed
along the handle. The adult grasp usually was not seen until 3 years of age. A second perceptual and motor act is the filling of the spoon. At first the bowl of the spoon is merely dipped in the dish, often with the spoon handle perpendicular. Filling began with a rotary movement toward the body, and it was not until 16 months that children began filling the spoon by inserting its point into the food. Lifting the spoon was at first accomplished with the arm pronated, and often with the bowl of the spoon tipping. By the end of the second year children were lifting their elbows and flexing their wrists. The insertion of the spoon into the mouth also changed from the side into the mouth to the point into the mouth. The third study reported by Connolly and Dalgleish (1989) confirmed many of the findings of Gesell and Ilg. They conducted a comprehensive videotape study on the longitudinal development of spoon use. The research procedure was more formal, and the study can serve as a model for the investigation of the learning of complex motor skills. The authors first presented an analysis of spoon use that included both intentional and operational aspects. The task was described as entailing: “… (a) an intention to eat, which involves the child’s motivation; (b) some knowledge about the properties of the spoon as an implement with which to effect the transfer of food from dish to mouth; (c) the ability to grasp and hold the spoon in a stable configuration; (d) the loading of food onto the spoon; (e) carrying the loaded spoon from dish to mouth; (f) controlling the orientation of the spoon during this transfer to avoid spillage; and (g) emptying the spoon and extracting it” (p. 897).
On the basis of this analysis, Connolly and Dalgleish conducted a longitudinal videotape study of the development in the operation of a spoon during the second year of life. Among their descriptions was an analysis of change in the action sequences from only two actions to a complex sequence that included corrections. The actions of putting a spoon in and out of a dish and putting the spoon in and out of the mouth initially were unconnected. Box 10-1 shows the progression and change of action sequences in using the spoon. This change in action sequences seems to indicate that the child was learning skill both in the performance of single actions and in the use of complex movement sequences. Connolly and Dalgleish also report other changes in motor actions, such as a smoothing of the trajectory of the dish-to-mouth path, and the shifting of the angle at which the spoon was placed from side toward mouth, to point toward mouth. Children used primarily a palmar grasp: the wrist, shoulder, and elbow movements also were described.
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Table 10-3
Self-feeding: use of utensils
Skill
Age
Source
Grasps spoon in fist
10–11 mo
Gesell and Ilg (1943)
Dips spoon in food, lifts to mouth
1 yr 3 mo
Gesell and Ilg (1943)
Fisted grasp, pronated forearm, turns spoon
1 yr 3 mo
Coley (1978)
Scoops food, lifts with spilling
11⁄2–2 yr
Haley et al. (1992)
Fills spoon, turns in mouth, spilling
11⁄2 yr
Coley (1978)
Spoon angled slightly toward mouth
11⁄2 yr
Gesell and Ilg (1943)
Tilts spoon handle up as removes from mouth
11⁄2 yr
Gesell and Ilg (1943)
Uses spoon well with minimal spilling
2–21⁄2 yr
Ha1ey et al. (1992)
Point of spoon enters mouth
2 yr
Gesell and Ilg (1943)
Inserts spoon into mouth without turning
2 yr
Gesell and Ilg (1943)
Fills by pushing point of spoon into food
2 yr
Gesell and Ilg (1943)
Grasps spoon with fingers (girls supinate)
3 yr
Gesell and Ilg (1943)
Fills spoon by pushing point or rotating spoon
3 yr
Gesell and Ilg (1943)
Holds spoon with fingers for solid foods
4 yr
Coley (1978)
Eats liquids, spoon held with fingers, few spills
4–6 yr
Coley (1978)
Spears and shovels food, little spilling
2–21⁄2 yr
Ha1ey et al. (1992)
Fork held in fingers
41⁄2 yr
Co1ey (1978)
Uses for spreading
5–51⁄2 yr
Ha1ey et al. (1992)
Spreads with knife
6–7 yr
Coley (1978)
Uses to cut soft foods (sandwich)
5–51⁄2 yr
Ha1ey et al. (1992)
Cuts meat with knife
7–8 yr
Coley (1978)
Uses utensils deftly and gracefully
8 yr
Gesell and Ilg (1946)
SPOON
FORK
KNIFE
Self-Care and Hand Skill • 203 BOX 10-1
Progression of Action Sequences in Using the Spoon
The first purposeful sequence was five steps: Spoon to dish Remove from dish Lift to mouth Put in mouth Remove from mouth Later, two more actions were added: Filling the spoon Removing food with lips The final action sequence included 11 steps that incorporated monitoring and correction through repetition of sequences: 1. Control of spoon 2. Spoon to dish 3. Steady dish with other hand 4. Remove spoon from dish 5. Check to see if there is enough food on spoon (if not, repeat 2 to 4) 6. Lift spoon 7. Put spoon in mouth 8. Empty spoon with lips 9. Remove from mouth 10. Check to see if spoon is empty (if not, repeat 7 to 9) 11. Pick up spilled food (repeat 6 to 8) 1. 2. 3. 4. 5.
Connolly K, Dalgleish M (1989). The emergence of a tool-using skill in infancy. Developmental Psychology, 25(6):894–912.
Serving and Preparing Food A part of independence in eating is serving oneself and preparing foods. Table 10-4 shows that by the time children enter school they can take care of simple preparation and self-service of food and drink. In the preschool years children also begin to help with simple household chores such as setting the table (3 to 4 years), putting away silverware (2 years), and wiping up spills (3 years) (Gesell & Ilg, 1943). One of the expectations of the nursery school children studied by Bott and co-workers (1928) was that their feeding area be cleaned up after they ate. At the age of 2 the children left the table, chair, and floor clean after eating in 45% of the observations. By the age of 4 years the percentage had increased to 85%. This change undoubtedly reflects the influence of nursery school expectations, as well as maturation.
DRESSING The development of self-care in dressing, undressing, and managing fasteners also parallels and depends on the development of hand skills. A fisted grasp is sufficient for the tasks of removing hat and socks. Pulling up pants requires more strength and bilateral coordination than pushing them down and kicking them off.
Individual finger function comes into play in loosening laces, and full independence in dressing requires complex finger manipulation of buttons and ties. The need for finger dexterity and planning sequences underlies the slow acquisition of management of fasteners. Key and her associates (1936) studied the process of learning to dress among 45 nursery school children, ages 11⁄2 to 51⁄2 years. Overall dressing ability was highly correlated with chronological age. They reported the learning process to be continuous, increasingly difficult, and unstable, and that the most rapid period of learning was between 11⁄2 years and 21⁄2 years. Overall success rates increased over the ages studied as follows: 11⁄2 years, 40%; 2 years, 50%; 21⁄2 years, 80%; and 31⁄2 years to 51⁄2 years, 90%. Other authors also have reported that dressing skills develop rapidly between 11⁄2 and 31⁄2 years (Gesell et al., 1940). Self-help in putting on and removing clothes is highly dependent on the type of clothing worn (Key et al., 1936). The variability in the age of acquisition is undoubtedly in part a result of the type of clothes selected for children by their caregivers. Characteristics of clothing that facilitate self-dressing include loose tops with large neck openings and loose pants with elastic tops and loose cuffs. The type and size of fasteners should be appropriate for children and they should be in reasonable locations (front or side). However, it should be noted that peer fashions may be important even for young children and compromises may be needed. The overall development of dressing skill proceeds from undressing, to dressing without fastening, to managing fasteners. Taking off an item of clothing is easier than putting it on because putting on clothing is more complex both motorically and perceptually. For example, socks slip off easily, but the coordination between the two hands and between hands and feet together are needed for putting socks on. Moreover, the sock must be rotated correctly to match its heel to the heel of the foot. Information on the chronology of dressing is presented in four areas: antecedents of dressing skills, undressing without fasteners, dressing without fasteners, and managing fasteners.
Antecedents of Dressing Skills Table 10-5 lists average ages at which children achieve abilities necessary for dressing. The earliest interaction with clothing, such as clutching and pulling at clothing, is meaningless in respect to self-care but demonstrates the ability to grasp. The early removal of hats and socks is also hardly purposeful undressing because it is just as likely to occur during dressing as undressing. Nevertheless, these actions demonstrate motor sequences that will later be used purposefully. Researchers have chronicled infant beginnings of cooperation and assistance in dressing (Gesell & Ilg,
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Table 10-4
Serving and preparing food
Skill
Age
Source
Unwraps food
11⁄2–2 yr
Vulpe (1979)
Opens jars
2 yr
Gesell and Ilg (1943)
Fixes dry cereal
4–5 yr
Vulpe (1979)
Serves self
4–5 yr
Vulpe (1979)
Makes sandwich
7 yr
Brigance (1978)
Prepares baked potato
8 yr
Gesell and Ilg (1946)
Pours from small pitcher
2–21⁄2 yr
Vulpe (1979)
Obtains drink from tap
3–31⁄2 yr
Gesell and Ilg (1943)
Pours from large pitcher or carton
4–41⁄2 yr
Haley et al. (1992)
Carries glasses without spilling
6 yr
Brigance (1978)
Uses napkin
4 yr
Brigance (1978)
Sets table with help
21⁄2–3 yr
Vulpe (1979)
Wipes up spills
3 yr
Gesell and Ilg (1943)
Sets table without help
4–5 yr
Vulpe (1979)
PREPARES FOOD
PREPARES DRINKS
OTHER SKILLS
Self-Care and Hand Skill • 205
Table 10-5
Antecedents of self-dressing skills
Skill
Age
Source
Clutches and pulls clothing
Up to 3 mo
Vulpe (1979)
Pulls off hat
6 mo
Vulpe (1979)
Pulls off booties
6–9 mo
Gesell and Ilg (1943)
Pulls off socks
9–10 mo
Vulpe (1979)
Passive (lies still)
3–6 mo
Vulpe (1979)
Holds arm out
9 mo
Coley (1978)
Lifts foot for shoe or pants
11⁄2–2 yr
Haley et al. (1992)
Tries to put on shoes
14–18 mo
Vulpe (1979)
Tries to assist with fasteners
2–21⁄2 yr
Haley et al. (1992)
Helps push down pants
2 yr
Coley (1978)
Interested in lacing
21⁄2–3 yr
Vulpe (1979)
Reaches to toes
1 yr 4 mo
Coley (1978)
Reaches above head bilaterally/unilaterally
2–5 yr
Coley (1978)
Reaches behind back, hands together
3–6 yr
Coley (1978)
Reaches behind head, hands together
4–6 yr
Coley (1978)
REACH AND GRASP
COOPERATION
Attempts skill
TRUNK STABILITY
206
Part II • Development of Hand Skills
1943). These early actions of pushing with arms or legs are components of later self-dressing. Furthermore, actions such as holding arms or legs out demonstrate the child’s understanding of the dressing process. Trying to assist (e.g., pulling at a zipper tab) may not be functional but is important because it demonstrates modeling behavior (Haley et al., 1992).
Undressing: Clothes Unfastened or Without Fasteners Table 10-6 identifies the sequences in which children learn to take off their clothes. Complete independence in undressing requires the release of fasteners, a skill that does not develop until after 3 years of age (Coley, 1978). However, with assistance in unfastening, the
Table 10-6
toddler can take off much clothing. Undressing requires only simple perceptual skills; knowing front from behind and left from right is unnecessary. Furthermore, fewer action sequences are needed than for dressing (Klein, 1983), and hand use requires little more than gross grasp, pulling, and pushing. Interest in taking clothes off begins in the first year; by 21/2 years most children can and want to take off their clothes, and by 3 years undressing is done well and rapidly (Gesell & I1g, 1943).
Dressing with Assistance on Fasteners Table 10-7 1ists the sequences in which dressing skills are acquired. The long 5-year developmental period is to a great extent a reflection of the perceptual skills
Undressing: clothes unfastened or without fasteners
Skill
Age
Source
Pulls off hat appropriately, on request
11⁄2 yr
Gesell and Ilg (1943)
Removes mittens
12–14 mo
Coley (1978)
Removes socks on request
11⁄2–2 yr
Haley et al. (1992)
Removes untied or unfastened shoes
11⁄2–2 yr
Haley et al. (1992)
Unties and removes shoes
2–3 yr
Coley (1978)
Pushes off pants if soiled
1 yr
Gesell and Ilg (1943)
Pushes down underpants or shorts
21–24 mo
Gesell and Ilg (1943)
Removes elastic top on long pants, clearing over bottom
2–21⁄2 yr
Haley et al. (1992)
Removes second arm from coat
1 yr
Brigance (1978)
Removes unbuttoned coat
1 yr
Brigance (1978)
Removes pullover garments, T-shirt, dress
21⁄2–3 yr
Haley et al. (1992)
Assistance needed
3 yr
Coley (1978)
Little assistance needed
4 yr
Coley (1978)
HAT AND MITTENS
SOCKS AND SHOES
PANTS AND PULL-DOWN GARMENTS
SHIRTS, COATS, AND SWEATERS
Self-Care and Hand Skill • 207
Table 10-7
Self-dressing: without fasteners
Skill
Age
Source
2 yr
Gesell et al. (1940)
Puts on with help on heel orientation
3 yr
Coley (1978)
Puts on heel correctly oriented
3–31⁄2 yr
Haley et al. (1992)
Pulls socks to full extension
4 yr
Key et al. (1936)
Gets shoe on halfway
11⁄2 yr
Gesell et al. (1940)
Puts on, may be on wrong feet
3–31⁄2 yr
Haley et al. (1992)
If laces are loosened
2 yr
Gesell et al. (1940)
Loosens laces and puts on
21⁄2 yr
Vulpe (1979)
Puts on correct feet
41⁄2–5 yr
Haley et al. (1992)
Puts on boots if loose fitting
3–4 yr
Vulpe (1979)
Independent with Velcro fastenings
41⁄2–5 yr
Haley et al. (1992)
Finds large armholes
2 yr
Coley (1978
Puts on coat with help
2 yr 9 mo
Coley (1978)
Puts on open-front shirt
31⁄2–4 yr
Haley et al. (1992)
Adjusts collar to neck
3 yr
Key et al. (1936)
Puts head through hole
2 yr
Key et al. (1936)
Puts on pullover garment
3–31⁄2 yr
Haley et al. (1992)
Puts arm through hole
31⁄2 yr
Key et al. (1936)
Pulls down over trunk
3 yr
Key et al. (1936)
Distinguishes front and back, inside out
4 yr
Coley (1978)
Helps pull pants up
2 yr
Gesell et al. (1940)
Tries to put on, two feet in one hole
2–21⁄2 yr
Gesell et al. (1940)
Puts on if oriented verbally
3–31⁄2 yr
Haley et al. (1992)
Orients correctly and puts on
4 yr
Coley (1978)
Can turn right side out
4 yr
Coley (1978)
HAT Puts on, may be backward
SOCKS
SHOES
COATS AND OPEN-FRONT SHIRTS
PULLOVER GARMENTS, T-SHIRTS, AND DRESSES
PANTS AND PULL-UP GARMENTS
208
Part II • Development of Hand Skills
needed. The last skills achieved are in the orientation of the heel of the sock, the front and back of garments, and, the most difficult, the distinguishing of left and right shoes. Children know when their coat is right side out when they are 3, but they have more difficulty with other clothes. The 4- to 5-year-old gets the underclothes right side out, but it is not until 7 years that the inside and outside of all clothes are discriminated (Brigance, 1978). In addition to these perceptual skills, self-care dressing skills require complex motor planning. Gaddes (1983) described the difficulty of some children with learning disabilities in dressing as a lack of the tactile and kinesthetic awareness essential to the task of putting on one’s clothes, and commented that “small children are usually unable to put on their clothes without help … not because they lack the physical strength but because they lack the necessary ideomotor image” (p. 109).
The hand skills needed are primarily whole-hand grasp, a power grasp for pulling clothing on, and a high level of bilateral skill. Hands must work smoothly and in unison to pull socks up to full extension, pull on boots, and pull up pants. Hands must work cooperatively in holding a shirt or coat with one hand while finding the armhole with the other. Additional bilateral dressing skills have been identified by Thornby and Krebs (1992). Their interest was in expectations for independence for children with unilateral below-elbow amputations. The skills identified include grasping and pulling up trousers or skirt (21⁄2 to 3 years), and grasping clothing while zipping a zipper (3 years 3 months to 4 years). The children with amputations achieved these skills several years later than most children. A Study of Dressing Key and her associates (1936) studied the ability of children to put on the clothing that they wore to nursery school and found wide differences in the ability to put on separate garments. Overall, socks and leg garments were found to be the easiest, followed by upper body garments and dresses. Shoes, because of their fasteners, were the most difficult. In addition to looking at the overall ability to put on the garments, the researchers recorded the success rate of separate dressing units for each garment. These data provided an index of the difficulty of the subskills needed for successful performance. An analysis of the percentage of success for each subskill at each age level shows the relative difficulties of the components of putting on shoes, socks, pull-down garments, dresses, and shirts. This list excludes fasteners, and open-front and slipover shirts were not differentiated. The order of difficulty
BOX 10-2
The Order of Difficulty in the Ability of Children to Put on Clothing
Put one leg in hole of pants Pulled up pants Shoe started on foot Opened shoe for foot Put head in neck hole of dress Put on dress correctly front to back Socks started over foot Put foot in shoe with heel down Pulled sock up on leg Kept tongue out of shoe while donning Put second leg in hole of pull-down garment Pulled sock up on foot Put pullover garment over head Put first arm in dress hole Adjusted dress when on Put second arm in sleeve hole of dress Shirt on correctly front to back Adjusted pants when on Put first arm in sleeve hole of T-shirt Adjusted shirt when on Put second arm in sleeve hole of T-shirt Pants on correctly front to back Adjusted heel of sock Key CB, White MR, Honzik WP, Heiney AB, Erwin D (1936). The process of learning to dress among nurseryschool children. Genetic Psychology Monographs, 18:67–163.
reported, based on the age group in which 50% or more of the children succeeded in the task, is listed in Box 10-2. Note that a part of an individual motor skill, such as putting on pants or socks, was easiest but complete achievement was the hardest. The difficulty young children have in dressing is a mix of a challenging perceptual task, such as locating the front of a T-shirt or the heel of a sock, and sometimes a complex motor act, such as maneuvering an arm into a second dress hole.
Fasteners: Zippers, Snaps, Buttons, and Ties Table 10-8 shows the range of average ages at which children are able to fasten and unfasten their clothing. Manipulating zippers, as long as it does not involve hooking and unhooking a separating zipper, is the easiest form of closure, whereas tying is the most difficult. The feature all fasteners have in common is the need for bilateral finger manipulation skills. Zippers require precision grip and pinch strength. The bilateral nature of this task is shown by the 3-year delay in skill acquisition in children with unilateral below-elbow amputations (Thornby & Krebs, 1992). Buttons
Self-Care and Hand Skill • 209
Table 10-8
Fasteners: ties, buckles, Velcro, snaps, zippers, buttons
Skill
Age
Source
Unties shoe bow
11⁄2 yr
Brigance (1978)
Pulls laces tight
21⁄2–3 yr
Vulpe (1979)
Tries to lace, usually incorrectly
3 yr
Coley (1978)
Laces shoes
4–5 yr
Coley (1978)
Ties overhand knot
5 yr 3 mo
Coley (1978)
SHOES: LACE AND TIE
Ties bow on shoes
1
6–6 ⁄2 yr
Haley et al. (1992)
Unties back sash of apron or dress
5 yr
Coley (1978)
Ties front sash of apron or dress
6 yr
Coley (1978)
Ties back sash of apron or dress
8 yr
Coley (1978)
Ties necktie
10 yr
Coley (1978)
Unbuckles belt or shoe
3 yr 9 mo
Coley (1978)
Buckles belt or shoe
4 yr
Coley (1978)
Inserts belt in loops
41⁄2 yr
Coley (1978)
41⁄2–5 yr
Haley et al. (1992)
Unsnaps front snaps
1 yr
Brigance (1978)
Unsnaps back snaps
3 yr
Brigance (1978)
SASHES AND NECKTIES
BUCKLES
VELCRO FASTENERS Manages shoes with Velcro
SNAPS
1
Snaps most snaps, front and side
3 ⁄2–4 yr
Haley et al. (1992)
Snaps back snaps
6 yr
Coley (1978)
Zips and unzips, lock tab
2–21⁄2 yr
Haley et al. (1992)
Opens front separating zipper
31⁄2 yr
Coley (1978)
Zips front separating zipper
41⁄2 yr
Coley (1978)
Opens back zipper
4 yr 9 mo
Coley (1978)
Closes back zipper
51⁄2 yr
Coley (1978)
Zips, unzips, hooks, unhooks, separates zipper
51⁄2–6 yr
Haley et al. (1992)
Buttons one large front button
21⁄2 yr
Coley (1978)
Unbuttons most front and side buttons
3 yr
Coley (1978)
Buttons series of three buttons
31⁄2 yr
Coley (1978)
Buttons and unbuttons most buttons
4–41⁄2 yr
Haley et al. (1992)
Buttons back buttons
6 yr 3 mo
Coley (1978)
ZIPPERS
BUTTONS
210
Part II • Development of Hand Skills
require precision grip with manipulation and with both hands working cooperatively. Strength is another component of the management of fasteners. Snaps require considerable strength in the fingers. Koch and Simenson (1992) examined functional skills in spinal muscle atrophy. Children with 1⁄2to 2-lb pinch strength needed minimal help in dressing. Children with less than 1⁄2-lb pinch strength had trouble with tying and buttoning. Managing fasteners is also a perceptual task, particularly buttoning and tying. For both these tasks vision is important for learning. It is only after considerable skill has been developed that back buttons and back bows can be accomplished, using touch and kinesthesia alone. Buttoning The ability to button has been included in developmental tests for many years, and it has been studied more than other fastenings. The ability develops in preschool over 2 to 3 years of age, and achievement depends in part on the location of the button. Stutzman (1948) examined the ability of preschool children to button buttons on a strip on a table. Children under 2 years of age failed to button one button, but by 21⁄2 to 3 years of age 72% of the children succeeded, albeit slowly. However, Key and co-workers (1936) reported that only 50% of their 3-year-old children succeeded in buttoning their shirts or dresses, and only 33% their pants. Wagoner and Armstrong (1928) reported a study of buttoning skill in 30 nursery school children between the ages of 2 and 5 years. They standardized the task by making jackets that were adjustable in size and which had front and side buttons. The major findings were: (a) children under 21⁄2 years seemed not to have the motor control needed to button; from 21⁄2 to 5 years speed of buttoning improved with age; (b) girls were better than boys, but the researchers noted that this result might have reflected an artifact of their sample; and (c) side buttons were much more difficult than front buttons; 25 children succeeded with the front buttons, but only 15 completed the side buttons (the authors noted that buttoning side buttons may require a more complex type of motor adjustment than do front buttons). Wagoner and Armstrong also reported correlation of buttoning speed with the Stanford-Binet Test (r = .33), the Merrill-Palmer Performance Tests (r = .62), and the Goodenough Drawing Test (r = .57). Thus buttoning appeared to be more related to performance tests than to intelligence. They also found success in buttoning to be highly correlated (.83 to .91) with teacher ratings on self-reliance, perseverance, and care of details.
Learning to Tie Shoes Shoe tying is an important and difficult developmental task for children. Children perceive the relationship of the loops and strings and learn the steps of looping, winding, and pulling through but still may fail. The most difficult aspect of shoe tying appears to be what Maccoby and Bee (1965) in their study of form copying termed the perception of attributes. Their example was that children discriminate forms such as diamonds but are unable to draw them because they do not perceive the attributes of the form, such as the relative size of lines and angles. Similarly, children do not perceive the relative sizes of loops and strings; the loop is too large and the bow fails. It is only when children perceive these attributes of the lacing process that they succeed. Learning to tie shoes is of special importance to a child’s sense of competence. The 6-year-old child has a sense of achievement and independence from adult help in the school environment.
HYGIENE AND G ROOMING Tables 10-9 and 10-10 present the sequences in which hygiene and grooming skills are acquired by children. The development of parts of the skills begins in early childhood, but independence in most hygiene and grooming skills is a middle childhood achievement. Many hygiene and grooming tasks are bilateral. Hands are rubbed together in washing; in drying, towels are held alternately while drying each hand. Applying toothpaste on a brush is a skilled bilateral activity. This was shown by the delay in which children with unilateral amputations were found to achieve this task (Thornby & Krebs, 1992). The toothbrush is a tool that requires a high level of skill, as wrist and hand movements are complex in placing the brush and brushing all the teeth. It is also a skill accomplished without vision. Independence in hair care is greatly influenced by social factors, especially for girls. At about the time when hair becomes manageable by the 4- to 7-year-old child, independence is often delayed in girls by choice of hairstyles (e.g., braids usually are a teenage accomplishment). Hair styling requires a complex manipulation of many tools—brush, comb, pins, dryers—all of which must be used without vision or with mirror vision. The ability to perform grooming and hygiene skills develops far earlier than the acceptance of responsibility for performing them. Grooming and hygiene skills are particularly likely to be neglected by school-age children. Note that the performance ages in the tables reflect when a child can do a skill and not whether it is done without supervision.
Self-Care and Hand Skill • 211
Table 10-9
Hygiene
Skill
Age
Source
11⁄2–2 yr
Haley et al. (1992)
WASHING AND DRYING HANDS Holds out hands to be washed
1
Dries with help
1 ⁄2 yr
Coley (1978)
Rubs hands together to clean
11⁄2–2 yr
Haley et al. (1992)
Turns faucet on and off
21⁄2–3 yr
Haley et al. (1992)
Dries hands thoroughly Dries without supervision
1
Haley et al. (1992)
1
Coley (1978)
1
3 ⁄2–4 yr 3 ⁄2 yr
Washes hands thoroughly
3 ⁄2–4 yr
Haley et al. (1992)
Washes without supervision
3 yr 9 mo
Coley (1978)
Disposes of paper towel or replaces towel
4 yr
Coley (1978)
Washes hands at appropriate time before meals
6 yr
Coley (1978)
Washes and dries face thoroughly
51⁄2–6 yr
Haley et al. (1992)
Without supervision
4 yr 9 mo
Haley et al. (1992)
Washes ears
8–9 yr
Haley et al. (1992)
Tries to wash body
11⁄2–2 yr
Haley et al. (1992)
Bathes down front of body
3 yr
Coley (1978)
WASHING FACE
BATHING BODY
1
Haley et al. (1992)
1
4 ⁄2 yr
Coley (1978)
Opens mouth for teeth to be brushed
1–2 yr
Haley et al. (1992)
Holds brush, approximates brushing
11⁄2–2 yr
Haley et al. (1992)
Brushes teeth, not thoroughly
2–21⁄2 yr
Haley et al. (1992)
Washes body well Soaps cloth and washes
3 ⁄2–4 yr
TEETH BRUSHING
Thoroughly brushes teeth
1
Haley et al. (1992)
1
4 ⁄2–5 yr
Prepares brush, wets and applies paste
4 ⁄2–5 yr
Haley et al. (1992)
Brushes routinely after meals
7 yr
Coley (1978)
11⁄2–2 yr
Haley et al. (1992)
1
2–2 ⁄2 yr
Haley et al. (1992)
Wipes without request
1
3–3 ⁄2 yr
Haley et al. (1992)
Attempts to blow nose
11⁄2–2 yr
Haley et al. (1992)
Blows and wipes alone
6–61⁄2 yr
Haley et al. (1992)
2–21⁄2 yr
Haley et al. (1992)
1
3–3 ⁄2 yr
Haley et al. (1992)
1
3–3 ⁄2 yr
Haley et al. (1992)
1
Haley et al. (1992)
Wipes self thoroughly
5 ⁄2–6 yr
Haley et al. (1992)
Completely cares for self at toilet
5 yr
Coley (1978)
NOSE CARE Allows wiping of nose Wipes on request
TOILETING Assists with clothing management Manages clothes before and after toileting Tries to wipe self after toileting Manages toilet seat, toilet paper, flushes
3–3 ⁄2 yr 1
212
Part II • Development of Hand Skills
Table 10-10
Grooming
Skill
Age
Source
Holds head in position for combing
1–11⁄2 yr
Haley et al. (1992)
Brings comb to hair
1–11⁄2 yr
Haley et al. (1992)
Brushes or combs hair; combs with supervision
21⁄2–3 yr
Haley et al. (1992)
Manages tangles and parts hair
7 yr
Haley et al. (1992)
Combs using mirror to check style
7 yr
Coley (1978)
Uses rollers, hair spray
12 yr
Coley (1978)
Shines shoes
7 yr
Brigance (1978)
Uses deodorant daily
12 yr
Coley (1978)
Scrubs fingernails with brush
51⁄2 yr
Coley (1978)
Maintains clean nails, files, clips both hands
8 yr
Coley (1978)
HAIR
OTHER GROOMING SKILLS
DISCUSSION Independence in the performance of the daily activities of basic self-care requires the mastery of complex hand skills that children learn over many years. The skills have varying degrees of manipulative, perceptual, and cognitive components and the action sequences are learned through extensive practice until they become automatic and efficient. We have some knowledge of the usual ages at which the skills are mastered, but very little knowledge of what Connolly and Dalgleish (1989) called the general patterns of behavioral change, which occur as children acquire specific selfcare skills. Most of the studies of the development of self-care skills cited in this chapter were conducted before 1940. There are not many, and recent studies are even scarcer. As noted by Amato and Ochiltree (1986), despite an increasing interest in the development of competence in childhood during the last decade, practical life skills have been virtually ignored. Interest in the study of children’s self-care skills over the years has been largely
limited to their use in identifying developmental milestones, and most of our knowledge is of that kind. The information in this chapter is a summary of what is currently known about the chronology of skill acquisition and is presented as a possible source for finding clues to the understanding of the process by which skills are acquired. Although the ages identified are approximate and represent an unspecified average behavior, they provide a tentative chronological order in which skills and subskills develop. However, it must be remembered the sequences of skill development that are suggested by the information in the tables may be an artifact of the use of group data. Of course, some of the steps in learning are clearly acceptable; that is, a partial skill precedes a complete skill and many of the sequences have been repeatedly observed and verified by teachers, parents, and therapists. However, individual differences among children could result in different routes to competence in an overall skill. Nevertheless, these overall sequences have value in that they provide information that could be used in planning longitudinal
Self-Care and Hand Skill • 213 studies because they identify the age span in which skills usually develop. Furthermore, they show general patterns of behavioral change in the acquisition of selfcare that allows some generalizations about factors affecting mastery.
the appropriate finger grasp position. These skills begin to develop in the third year but the combination of precision and power in finger manipulation at the highest level does not develop until a child is 8 years old.
HAND SKILLS IN SELF-CARE
Bilateral Hand Use
The examination of the chronology of self-care acquisition allows a preliminary, although fragmentary, analysis of the relationship of the development of hand use to the development of self-care. We do not know when these self-care skills reach adult levels of efficiency and precision, but clearly skill acquisition is a gradual process that extends into the preteens. It appears that aspects of hand skill acquisition over the years include (a) finger manipulation and grip ability, (b) the use of two hands in a complementary fashion, (c) the ability to use the hands in varied positions with and without vision, (d) the execution of increasingly complex action sequences, and (e) the development of automaticity. These hand skills have been discussed in the preceding section in relation to specific skills and are summarized in the following.
Most self-care skills are bilateral and the challenge posed by these skills depends on their complexity. The simple act of drinking from a bottle and then a cup held in two hands is one of the first achievements of an infant, and an infant is soon able to hold a dish while spooning food. The order in which bilateral dressing skills develop seems to depend on the added need for power, whether hands work in unison or cooperate in different functions, and the extent of the motor sequencing involved. Undressing is easier with two hands but requires less skill than does dressing. Intermediate bilateral skills include pulling up pants, holding a shoe open with the tongue out, and pulling on boots. Manipulating buttons, buckles, and zippers is more difficult because high precision is necessary and the two hands work cooperatively but differently. The greatest difficulty comes when the two hands must move through different motor sequences, as in tying bows.
Grip Ability and Finger Manipulation During the first year of life the infant develops whole hand grip followed by the use of a finger grip with some precision (see Chapter 7). As grips develop they are used in self-care skills, first with the whole hand and then with the fingers. Therefore the earliest self-care actions are pulling at clothes and grasping food such as a cracker with the whole hand. Finger feeding soon follows the early emergence of pincer grasp. This whole hand to pincer grip sequence occurs repeatedly as skills develop. Examples in the young child include progression from a whole hand to a finger grip on a spoon and from a whole hand grip pulling up pants to a thumb and finger grip on socks. This progression of the whole hand grip to pincer grip sequence is in part a reflection of the interplay of power and precision in grip as skill develops, as the infant has power in the whole hand grip, but is slow to develop power in finger grips. For example, a child lifts a cup or glass with one hand before having the finger grip power needed for lifting a cup by the handle. In cutting with a knife and fork, a child first uses a fisted grip on both utensils to exert the pressure needed. The power finger grips used by adults for cutting are not achieved until the preteen years. The use of the fingers in a precision pincer grip is used in dressing in the second year, but fasteners such as buttons, shoe lacing, bow tying, and buckles, require in-hand manipulation skills. In-hand manipulation also is needed to position a spoon or toothbrush for
Position of the Hands Two factors appear to influence a child’s ability to perform a task with the hands someplace other than in front of the body. Young children seem unable to perform tasks such as buttoning without seeing their hands, and performing with the hands in awkward positions such as at the side of the body is difficult. These two factors probably combine to delay learning to manipulate back buttons until after the sixth year.
Executing Motor Sequences As was noted in the discussion of spoon use, even the early-developing task of self-feeding requires the learning of a multiple sequence of actions. Through analysis, therapists have identified the steps involved in many dressing skills (Case-Smith, 2000), but the sequence followed by typical children in learning particular dressing skills has not been studied. However, it is to be expected that becoming self-sufficient in a skill is in part a reflection of the number of action sequences involved.
Automaticity Self-care literature provides a clue to the development of automaticity in skill performance. There appears to be a delay following a child’s ability to perform a skill in eating and dressing before the skill can be performed while carrying on a conversation (Hurlock, 1964; Klein, 1983). This suggests that an automatic level of
214
Part II • Development of Hand Skills
skill execution does not develop until several years after a skill is first mastered.
Combined Motor Abilities Examples of skills involving different facets of hand manipulation have been given for illustrative purposes. Nevertheless, clearly most of these facets occur in combination. The highest level of self-care skill appears to require some combination of bilateral sequencing and complementary hand use, the combination of power and precision in grip, the ability to perform hand tasks with the hands behind the back or head, and the ability to visualize what the hands are doing when they are out of sight. Tying a necktie involves multiple complex sequences, bilateral, complementary hand use, and performance without vision, and is one of the last skills learned.
PERCEPTUAL FACTORS IN SELF-CARE The sequences of self-care acquisition also clearly demonstrate the need for development of perceptual skills. Perceptual skills are necessary for tool use, ranging in difficulty for spoons, toothbrushes, and combs. Perceptual factors are particularly evident in dressing. Over several years children learn, in this order, whether clothes are inside out or outside out, the difference between front and back, and which is left or right. Their ability to respond first to more obvious cues is shown by this sequence, as well as by their ability to locate a dress front by its decoration before the back of a T-shirt by its label or the front of pants.
COGNITIVE AND PERSONALITY FACTORS IN SELF-CARE We have little data on the importance of cognitive and personality factors in self-care acquisition, but the few studies suggest that, for children whose intelligence is within normal limits, the level of intelligence is less important than the personality characteristics of persistence and self-reliance. There is good reason to believe that in typical children personal and social characteristics are as important as perceptual and motor maturation. Children are highly variable in the chronological ages at which they acquire skills, and the finding that a 3- to 4-year span may separate the earliest and latest age at which typical children master a particular skill is a powerful indication that there are large personal and situational differences among children. We know very little about the sources of these individual differences, but we can hypothesize that they are multiple and include differences in problem-solving abilities, persistence, and self-reliance. We also know
virtually nothing about the extent to which and in what combinations these intrinsic factors influence the maturation of self-care skills or how much is a function of family and cultural variables. Many studies are needed to understand the variables that have an impact on the learning of self-care skills. The PEDI promises to provide a rich resource for the determination of which cultural, cognitive, motor, and personality factors have an impact. The interest in researching the development of competence and volition will also hopefully include more attention to basic practical skills.
SUMMARY This chapter has focused on how and when typical children learn the separate skills and subskills of selfcare. Knowledge of the sequences in which typical children acquire self-sufficiency in daily activities can be valuable in understanding the roadblocks for children with physical or mental disability, and sequences of skill acquisition can provide guidance in selecting the level of skill at which to introduce training. However, the acquisition of self-care in typical children provides only a part of the picture needed for treatment planning. We must learn how skills are learned in the presence of different disabilities. We know that the presence of a specific disability can change the sequence in which a child will master self-care skills, but we have little information about what that sequence is. Most of our knowledge about the impact of disability on specific self-care skills comes from therapeutic accounts. Several recent publications have provided detailed task analyses of methods of dressing, eating, and hygiene keyed to different impairments and include multiple suggestions for adaptations. Some of these are designed for children (e.g., Case Smith, 2000; Shepard, 2001), and others for adults (e.g., Backman & Christiansen, 2000; Holm, Rogers, & James, 1998; Snell & Vogtle, 2000). The tables also provide useful knowledge about the acquisition of part skills. Typically children do not learn a skill all at once. Rather they are encouraged to do what they can long before they are developmentally ready to master a skill. Parents of children with disabilities should be encouraged to introduce part-skill practice early and to set expectations that their child do whatever he can. This will take more time but it will contribute to the child’s sense of mastery and selfesteem and provide practice of the motor skill. It would be helpful to know more about the factors affecting such a learning process and the differences and similarities in the ways in which children with disabilities learn complex skills.
Self-Care and Hand Skill • 215 The importance of self-care skill acquisition in a typical child’s sense of efficacy and the parent–child interaction around self-care issues should be investigated. Furthermore, although we know that independence in self-care is important to an individual’s quality of life, disability sometimes is so severe that independence cannot be achieved, and we know little about the importance of partial independence to the individual or of its meaning to an individual’s sense of mastery and control. Research in self-care with both typical children and children with disabilities has the potential for discovering information that will be applicable to designing rehabilitation programs. Parents should be helped to understand the importance of the mastery of self-care skills to the child and to give the child a sense of pride in this most mundane of accomplishments. Time in the daily schedule is needed for practice of self-care for all children. The child with a disability has a different timetable for mastery, but the same rules should apply. Time must be scheduled for every child to master skills, and develop the self-reliance and self-confidence that comes with mastery.
REFERENCES Amato PR, Ochiltree G (1986). Children becoming independent: An investigation of children’s performance of practical life-skills. Australian Journal of Psychology, 38(1):59–68. American Occupational Therapy Association (1994). Uniform terminology for occupational therapy, 3rd ed. American Journal of Occupational Therapy, 48:1047–1054. American Psychiatric Association (1994). Diagnostic and Statistical Manual IV (4th ed.). Washington, DC, Author. Backman C, Christiansen CH (2000). Assessment of selfcare performance. In C Christiansen, editor: Ways of living: Self-care strategies for special needs (pp. 29–44). Bethesda, MD, American Occupational Therapy Association. Bleck EE, Nagel DA (1975). Physically handicapped children: A medical atlas for teachers. New York, Grune & Stratton. Bott EA, Blatz WE, Chant N, Bott H (1928). Observation and training of fundamental habits in young children. Genetic Psychology Monograph, 4:1–161. Brigance AH (1978). Diagnostic inventory of early development. North Billerica, MA, Curriculum Associates. Bullock M, Lutkenhaus P (1988). The development of volitional behavior in the toddler years. Child Development, 59:664–674. Carruth BR, Skinner JD (2002). Feeding behaviors and other motor development in healthy children (2–24 months). Journal of the American College of Nutrition, 21(2):88–89. Case-Smith J (2000). Self-care strategies for children with developmental disabilities. In C Christiansen, editor: Ways of living: Self-care strategies for special needs (pp. 81–121).
Bethesda, MD, American Occupational Therapy Association. Castle K (1985). Toddlers and tools. Childhood Education, 16(May/June):352–355. Cermak SA, Larkin D (2002). Developmental coordination disorder. Albany, NY, Delmar Thomson. Chen CC, Heinemann AW, Bode RK, Granger CV, Mallison T (2004). Impact of pediatric rehabilitation services on children’s functional outcomes. American Journal of Occupational Therapy, 58:44–53. Christiansen CH (2000). The social importance of self-care intervention. In C Christiansen, editor: Ways of living: Self-care strategies for special needs (pp. 1–11). Bethesda, MD, American Occupational Therapy Association. Coley IL (1978). Pediatric assessment of self-care activities. St Louis, Mosby Coley IL, Procter S (1989). Self-maintenance activities. In PN Pratt, AS Allen, editors: Occupational therapy for children, 2nd ed. St Louis, Mosby. Connolly K, Dalgleish M (1989). The emergence of a tool-using skill in infancy. Developmental Psychology, 25(6):894–912. Dumas HM, Haley SM, Fragala MA, Steva BJ (2001). Selfcare recovery of children with brain injury: Descriptive analysis using the Pediatric Evaluation of Disability Inventory (PEDI) functional classification levels. Physical Occupational Therapy in Pediatrics, 21(2–3):7–27. Eisen M, Donald CA, Ware JE, Brook RH (1980). Conceptualization and measurement of health for children in the health insurance study. Santa Monica, CA, RAND. Gaddes WH (1983). Learning disabilities and brain function. New York, Springer-Verlag. Gannotti ME, Handwerker WP (2002). Puerto Rican understandings of child disability: Methods for the cultural validation of standardized measures of child health. Social Science and Medicine, 55:2093–2105. Gannotti ME, Cruz C (2001). Content and construct validity of a Spanish translation of the Pediatric Evaluation of Disabilities Inventory for children living in Puerto Rico. Physical Occupational Therapy in Pediatrics, 20(4):7–24. Geppert U, Kuster U (1983). The emergence of “Wanting to do it oneself”: A precursor of achievement motivation. International Journal of Behavioral Development, 6:355–369. Gesell A, Amatruda CS (1965). Developmental diagnosis, 2nd ed. New York, Harper & Row. Gesell A, Ilg F (1937). Feeding behavior of infants. Philadelphia, JB Lippincott. Gesell A, Ilg F (1943). Infant and child in the culture of today. New York, Harper & Row. Gesell A, Halverson HM, Thompson H, Ilg FL, Castner BM, Ames LB, Amatruda CS (1940). The first five years of life: A guide to the study of the preschool child. New York, Harper & Row. Gesell AL, Ilg F (1946). The child from five to ten. New York, Harper & Row. Gordon N (1992). Independence for the physically disabled. Child Care, Health and Development, 18:97–105. Gubbay SS (1975). The clumsy child: A study of developmental apraxia and agnostic ataxia. Philadelphia, Saunders. Haley SM, Coster WL, Ludlow LH, Haltiwanger JT, Andrellos PJ (1992). Pediatric evaluation of disability inventory. Boston, New England Medical Center Hospital and PEDI Research Group.
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Hauser-Cram P, Warfield ME, Shonkoff JP, Krauss MW (2001). Children with disabilities: A longitudinal study of child development and parent well-being. William F Overton, editor: Monographs of the Society for Research in Child Development, 66(3):1–126. Holm MB, Rogers JC, James HB (1998). Treatment of activities of daily living. In ME Neistadt, EB Crepeau, editors: Willard and Spackman’s occupational therapy, 9th ed. Philadelphia, Lippincott Williams & Wilkins. Hurlock EB (1964). Child development, 4th ed. New York, McGraw-Hill. Inglis S (1990). Are there schoolchildren in Lewisham who are experiencing practical difficulties at home and/or at school? British Journal of Occupational Therapy, 53(4):151–154. Kelley SA, Brownell CA, Campbell SB (2000). Mastery motivation and self-evaluative affect in toddlers: Longitudinal relations with maternal behavior. Child Development, 71(4):1061–1071. Key CB, White MR, Honzik WP, Heiney AB, Erwin D (1936). The process of learning to dress among nurseryschool children. Genetic Psychology Monographs, 18:67–163. Klein M (1983). Pre-dressing skills. Tucson, AZ, Community Skill Builders. Koch BM, Simenson RL (1992). Upper extremity strength and function in children with spinal muscular atrophy type II. Archives of Physical Medicine and Rehabilitation, 73:241–245. Liu M, Toikawa H, Seki M, Domen K, Chino N (1998). Functional Independence Measure for Children (WeeFIM): A preliminary study in nondisabled Japanese children. American Journal of Physical Medicine and Rehabilitation, 77(1):36–44. Maccoby EM (1980). Social development: Psychological growth and the parent–child relationship. New York, Harcourt, Brace, Jovanovich. Maccoby EM, Bee HL (1965). Some speculations concerning the gap between perceiving and performing. Child Development, 36:367–378. May-Benson T, Ingolia P, Koomar J (2002). Daily living skills and developmental coordination disorders. In SA Cermak, D Larkin, editors: Developmental coordination disorder. Albany, NY, Delmar Thomson. Miller A, Stewart M, Murphy MA, Jantzen A (1955). An evaluation method for cerebral palsy. American Journal of Occupational Therapy, 9:105–111. Ottenbacher KJ, Msall ME, Lyon N, Duffy LC, Ziviani J, Granger CV, Braun S (2000). Functional assessment and care of children with neurodevelopmental disabilities. American Journal of Physical Medicine and Rehabilitation, 79(2):114–123. Parker ST, Gibson KR (1977). Object manipulation, tool use and sensorimotor intelligence as feeding adaptations in cebus monkeys and great apes. Journal of Human Evolution, 6:623–641. Senft KE, Pueschel SM, Robison NA, Kiessling (1990). Level of function of young adults with cerebral palsy. Physical Occupational Therapy in Pediatrics, 10(1):19–21.
Shepard J (2001). Self-care and adaptations for independent living. In J Case-Smith, editor: Occupational therapy for children. St Louis, Mosby. Skold A, Josephson S, Eliasson AC (2004) Performing bimanual activities: The experiences of young persons with hemiplegia cerebral palsy. American Journal of Occupational Therapy, 56(4):416–425. Snell ME, Vogtle LK (2000). Methods of teaching self-care skills. In C Christiansen, editor: Ways of living: Self-care strategies for special needs (pp. 57–81). Bethesda, MD, American Occupational Therapy Association. State University of New York at Buffalo (1994). Functional Independence Measure for Children (Wee Fim). Buffalo, NY, State University of New York at Buffalo. Stutzman R (1948). Guide for administering the Merrill Palmer Scales of Mental Tests. New York, Harcourt, Brace & World. Thornby MA, Krebs DE (1992). Bimanual skill development in pediatric below-elbow amputation: A multicenter, cross-sectional study. Archives of Physical Medicine and Rehabilitation, 73:697–702. Tsuji T, Liu M, Toikawa H, Hanayama K, Sonoda S, Chino N (1999). ADL structure for nondisabled Japanese children based on the Functional Independence Measure for children (WeeFIM). American Journal of Physical Medicine & Rehabilitation, 78(3):208–212. Vulpe SG (1979). Vulpe Assessment Battery for the atypical child. Toronto, NI on Mental Retardation. Wacker DP, Harper DC, Powel WJ, Healy A (1983). Life outcomes and satisfaction ratings of multi-handicapped adults. Developmental Medicine and Child Neurology, 25:625–631. Wagoner LC, Armstrong EM (1928). The motor control of children as involved in the dressing process. Journal of Genetic Psychology, 35:84–97. Wallander JL, Pitt LC, Mellins CA (1990). Child functional independence and maternal psychosocial stress as risk factors threatening adaptation in mothers of physically or sensorially handicapped children. Journal of Consulting and Clinical Psychology, 58(6):818–824. Walton JN, Ellis E, Court SDM (1962). Clumsy children: A study of developmental apraxia and agnosia. Brain, 85:603–612. White RN (1959). Motivation reconsidered: The concept of competence. Psychological Review, 66:297–333. Wolf J (1969). The results of treatment in cerebral palsy. Springfield, IL, Charles C Thomas. Wong V, Wong S, Chan K, Wong W (2002). Functional Independence Measure (WeeFIM) for Chinese children: Hong Kong cohort. Pediatrics, 109(2):317–319. Ziviani J, Otterbacher KJ, Shepard K, Foreman S, Astbury W, Ireland P (2001). Concurrent validity of the Functional Independence Measure for Children (WeeFim) and the Pediatric Evaluation of Disabilities Inventory in children with developmental disabilities and acquired brain injuries. Physical Occupational Therapy in Pediatrics, 21(2/3):91–101.
Chapter
11
THE DEVELOPMENT OF GRAPHOMOTOR SKILLS Jenny Ziviani • Margaret Wallen
CHAPTER OUTLINE GENERAL GRAPHOMOTOR COMPETENCY Acquisition of Graphomotor Skills Implement Grasp and Manipulation DRAWING The Nature of Drawing Computers and Drawing Drawing and Developmental Evaluation HANDWRITING Handwriting and Writing: Complementary Concepts The Developmental Nature of Handwriting Factors Contributing to Handwriting Performance Computers and Handwriting SUMMARY
This chapter provides information on the development and execution of graphomotor skills, as a basis for remediation. Concepts common to both drawing and handwriting such as motor learning theory and grasps used with writing and drawing tools are discussed first. Following are detailed sections on drawing and then handwriting. The emphasis in these sections is on outlining research that broadens our knowledge of the development of drawing and handwriting and deepens our understanding of the factors that are associated with graphomotor difficulties. Graphomotor skills comprise those conceptual and perceptual-motor abilities necessary for drawing and handwriting. Drawing is defined as the art of producing a picture or plan with implements such as pencils, pens, or crayons. Handwriting is the process of forming
letters, figures, or other significant symbols, predominantly on paper. Both these activities can be used to record experiences or thoughts, as well as communicate these to others. Drawing and handwriting are complex motor behaviors in which psychomotor, linguistic, and biomechanical processes interact with maturational, developmental, and learning processes (SmitsEngelsman & Van Galen, 1997). The need to develop proficiency in activities as fundamental as drawing and handwriting may be questioned in relation to the growing reliance on electronic communication devices. It is the position of this chapter that graphomotor skills represent more than a means of recording thoughts or conveying experiences. Developmentally these skills allow for experimentation and self-expression in the way a child interacts with the environment. Furthermore they are a means by which children learn basic tool use and are able to produce a product that is socially recognized and rewarded. As such they form an important part of the development of an individual.
GENERAL GRAPHOMOTOR COMPETENCY ACQUISITION OF G RAPHOMOTOR SKILLS Children, when presented with tools for inscription, readily smear paint, scribble with crayons, or draw. The nature of the inscription varies depending on the developmental status of individuals and their motor learning in relation to prior exposure to graphomotor experiences. In its most basic form simple inscription with an implement onto a page can be understood as a perceptual-motor act (van Galen, 1991). The learning of a skilled task such as handwriting or drawing,
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Task
• Sensory perception • Cognition • Motor control • Affective state • Motor planning • Biomechanical considerations
• Demands of task (cognitive, attentional, linguistic) • Nature of task (copied, self-generated, creative, academic) • Speed and accuracy • Skilled manipulative task
Skilled Handwriting Environment • Writing materials (implements, paper) • Furniture • Ambient features (temperature, lighting, noise) • Expectations of others • Exposure to instruction and practice
Figure 11-1 Skilled handwriting demands interplay among the individual, the task, and the environment.
however, involves an interplay among the individual, task, and environment (Shumway-Cook & Woollacott, 2001). Figure 11-1 summarizes these with respect to handwriting (Jongmans et al., 2003; Shumway-Cook & Woollacott, 2001). Each child’s individual capacity to mesh the task and the environmental contributions to handwriting determines the extent to which effective handwriting will be acquired.
Motor Learning Handwriting and drawing have been conceptualized as learned motor tasks. Motor learning theorists explain the control of coordinated movement in terms of openand closed-loop systems (Mathiowetz & Bass-Haugen, 2002; McGill, 1998). The closed-loop system involves afferent feedback. In the case of handwriting, feedback is received from the pressures exerted on the writing implement and the writing surface, from the senses of touch and movement in the fingers, hand, and arm, and from visually monitoring written work. This afferent feedback is used to update the nervous system about the accuracy of the handwriting. The feedback is
used to modify and control subsequent handwriting. In open-loop control systems there is no afferent feedback and the central nervous system directs movement. Theorists have postulated that the acquisition of drawing and handwriting skills can be understood best within the framework of a closed-loop theory. That is, afferent feedback is relied on to learn the skill. However, once learned, it is postulated that handwriting moves into the domain of an open-loop skill (van der Meulen et al., 1991). This means that instead of remaining dependent on vision and other sensory feedback, the skilled writer is able to write so quickly that there is no time to modify performance on the basis of afferent feedback. Movements that are entrenched in memory may predominate as handwriting becomes a proficient skill (Grossberg & Paine, 2000). In reality, the environmental and task demands of handwriting are diverse and dynamic and preprogrammed motor acts are not adequate to respond to the changing requirements of various handwriting tasks. Consequently it is more likely that closed- and open-loop systems work cooperatively, interacting with the various individual task and environmental factors to achieve handwriting output (Mathiowetz & Bass-Haugen, 2002).
The Roles of Vision and Kinesthesis Vision is essential to children learning to handwrite as they plan, execute, and monitor their attempts. Reliance on vision generally diminishes as skilled handwriting develops and feedback provided by the somatosensory system has greater influence in directing skilled and precise movement (Cornhill & Case-Smith, 1996). However, the visual sense is thought to remain active in children who are experiencing difficulties in mastering handwriting. Wann (1987) found that good and poor writers used different movement patterns when asked to reproduce letters and words. Wann recorded the performance of good and poor handwriters using an xy digitizer, and movement patterns were categorized according to their velocity and acceleration characteristics. Poor handwriters used more patterns of movement indicative of reliance on visual feedback as a major source of environmental information during handwriting. Although not suggesting that the more proficient writers were not using visual feedback during letter production, Wann (1987) postulated that they were probably less dependent on it as a means of control. He went on to point out that deprivation of visual feedback resulted in the deterioration of even the most proficient writer’s performance. Other researchers (van der Muelin et al., 1991) have supported the view of Wann and suggest that children with difficulty in visualmotor control compensate by adopting a greater reliance on visual monitoring and that this in turn results in slower performance. These issues warrant greater atten-
The Development of Graphomotor Skills • 219 tion because they can influence the adoption of appropriate remedial strategies. The role of kinesthesia is frequently discussed in relation to drawing and, particularly, handwriting. Kinesthesis relates to the information received from muscles, joints, and skin about body and limb position, and the direction, extent, and velocity of movement (Harris & Livesay, 1992; Sudsawad et al., 2002). An impairment of kinesthesis may influence the refinement of fine motor skills; children are not able to perceive and therefore monitor and correct errors of movement, particularly those of small amplitude, which are observed in handwriting (Harris & Livesay, 1992). Much of the work around kinesthesis in relation to handwriting involves the Kinesthetic Sensitivity Test (KST). This norm-referenced test consists of two subtests: Kinesthetic Acuity and Kinesthetic Perception and Memory. Each subtest has specific equipment that was designed to eliminate the need for motor control, thus allowing passive movement of children’s hands and arms to determine kinesthetic ability. Laszlo and Bairstow (1985a) developed the test to identify kinesthetic deficits and reported that training children using this test equipment resulted in improved drawing skills in children with poor kinesthesis. However, the relative importance of the role of kinesthesis in acquisition of proficient handwriting remains unclear. This subject is elaborated on in the review of handwriting later in this chapter.
I MPLEMENT G RASP AND MANIPULATION Brushes, crayons, pencils, felt-tip markers, and pens are the primary tools used by children in their graphic endeavors. These implements form an extension of the hand, and their control and manipulation are important in attaining skilled copying, drawing, and handwriting. Only through experimentation do children become skilled in adapting to implements of different weight, length, and graphic quality. Different grasps may be adopted with a change in implement and task to achieve an optimal outcome (Schwartz & Reilly, 1980; Thelen & Smith, 1994).
Grasps Many children acquire a dynamic tripod grip by about 61⁄2 years of age as their means of implement manipulation for drawing and handwriting. Children progress through a range of precursor grips—palmar, incomplete tripod (or palmar supinate), and static tripod— before adopting the dynamic tripod grip (Dennis & Swinth, 2001; Rosenbloom & Horton, 1971; Saida & Miyashita, 1979). Schneck and Henderson (1990) propose a 10-grip scale to classify the developmental range of grasps. Level 1, or the lowest level of the scale,
describes a palmar grasp, whereas Level 10 describes a dynamic tripod grasp. The scale is a “wholeconfiguration system,” which means that all the components of the grip can be described together rather than evaluating various components of a grip separately. Adoption of a scale such as this has the potential to inform comparisons with and between children and to contribute to a system of uniform terminology (Windsor, 2000). The dynamic tripod grasp, generally viewed as the mature grasp, is one in which the writing implement is grasped between the radial surface of the middle finger and the pulp surface of the thumb and index finger, with the thumb relatively opposed (Elliott & Connolly, 1984). However, not all children acquire or use this grip. Research suggests that the dynamic tripod is used by only 50% to 70% of children in a given sample (Benbow, 1987; Blote & van der Heijden, 1988; Dennis & Swinth, 2001; Schneck & Henderson, 1990). Other grasps, such as the lateral tripod and quadripod, also allow ulnar stability and controlled dynamic finger movement, which are considered important for skilled handwriting. Diverse ways of categorizing variations in the dynamic tripod grip have been used. Ziviani & Elkins (1986) used a series of four nonexclusive categories that described grips on the basis of the number of fingers held on the shaft of the writing implement, degree of forearm supination, hyperextension of the distal interphalangeal joint of the index finger, and thumb and index finger opposition. Sassoon, NimmoSmith, and Wing (1986) used a classification of pen holds that examined the position of digits on the pencil shaft, their proximity to the writing tip, and the shape of the digits. Furthermore, Sassoon described grips in relation to the shaping of the hand, the positioning of the upper body, and the specific orientation of the writing paper. Neither Sassoon nor Ziviani’s studies found writing speed was compromised by unconventional pencil holds. Subsequent studies have confirmed that grips affect neither legibility (Koziatek & Powell, 2003) nor the undertaking of long writing passages (Dennis & Swinth, 2001). However, all these studies have been undertaken with children without identified disabilities, and have not taken into account the dynamic aspect of adopted grips. Schneck (1991) found that children who used variants of the dynamic tripod grip also had impairment of proprioceptive/kinesthetic finger awareness. Schneck hypothesized that the grips may not themselves lead to poor handwriting but, in conjunction with poor proprioceptive and kinesthetic perception, might contribute to poor handwriting performance. Research that examined the impact of joint laxity has supported this view (Summers, 2001). In Summers’ study, positive
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but nonsignificant trends emerged between joint laxity and the failure to develop a dynamic tripod grip in 55 7-year-old children. Poorly established hand preference has been linked to developmentally immature grips (Rosenbloom & Horton, 1971; Schneck, 1989), but also can result from insufficient prerequisite experience. Poor hand preference is thought to impede the refinement of the manipulative skills needed for good pencil control. This view is consistent with Exner’s (1990) posit that the development of in-hand manipulation skills is dependent on well-defined hand preference. In a practical and clinical sense, therapists are confronted by the issue of whether to assist children to modify the grip they are using as part of an overall strategy to facilitate an improvement in handwriting performance. The following points may be worth considering when this situation arises: 1. Mechanically the dynamic tripod grip offers a high level of precision and control (Elliott & Connolly, 1984). The dynamic tripod grip should be encouraged when the child is young enough and has not developed a fixed writing posture. In fact some have argued that inadequate training in the use of a dynamic tripod grip is one of the reasons it is not used by greater numbers of children (Benbow, 1995). 2. Variations of the dynamic tripod grip do not, of themselves, contribute to handwriting difficulties. In typically developing students there appears to be no difference in the speed or legibility of handwriting using the dynamic tripod versus atypical dynamic grasps (Dennis & Swinth, 2001; Sassoon, et al., 1986; Ziviani & Elkins, 1986). Differentiation should be made, however, between a modified version of the dynamic tripod grip and a grip that is developmentally immature. The latter may be part of a broader picture of developmental difficulty. More research is necessary to determine if there is a relationship between typical and atypical grasps and legibility in children who are poor handwriters (Schneck, 1991).
Writing Implements A further issue related to implement manipulation is the nature or type of writing tool used. Traditionally young writers are given lead pencils with a larger than normal lead and barrel for drawing and handwriting instruction. This practice is based on the premise that it is easier for their small hands to hold and manipulate a larger barrel. However, studies have demonstrated that the legibility of kindergarten children’s handwriting is not associated with the tool used (Oehler et al., 2000). The maturity of grasp employed, nevertheless, may vary with the specific tool used (Yakimishyn & MagillEvans, 2002).
This section of the chapter outlined the processes involved in acquiring proficient use of tools for drawing and handwriting and about the grasps used when manipulating these tools. The next section is about the development of drawing ability.
DRAWING THE NATURE OF DRAWING When considering drawing, the simple copying of shapes and figures should be differentiated from the creation of pictures from memory or imagination. The present discussion is concerned primarily with copying skills (the perceptual-motor elements of drawing). Certain characteristics are thought to distinguish younger children’s drawings from those of adults. Children’s drawings have been described as being formula-like and depicting subjects as they are perceived to be rather than how they look (Freeman, 1980). Apart from exceptional children (Selfe, 1985), most children in their preschool and early school years construct their drawings from simple geometric forms and do not compose broad outlines that are then detailed. Fenson (1985), in a detailed longitudinal study of one child, found that a fundamental shift occurred between 3 and 7 years of age in the structure of drawing. The child moved from a constructional style to the use of contoured forms. The term constructional in this context relates to the assembling of simple geometric forms into a pictorial representation (e.g., the use of a circle for a face and a rectangle for a body when drawing a person). The term contoured, on the other hand, refers to the sketching of an outline, which is subsequently detailed to achieve the desired representation. Although no attempt is made to explain why a shift might occur from the former to the latter, it is postulated that the motivation is a quest for realism. This quest, in conjunction with greater skill in visually controlling actions and the ability to plan spatially and execute actions, constitutes the move from a juvenile to a more adult approach to drawing. Obviously such assumptions require further investigation. There has been little advance on the seminal work of authors such as Luquet (1927) and Kellogg (1969) when considering the maturation of children’s drawings. These authors considered that children between the ages of 2 and 3 years make scribbling marks on paper with no representational intent. The fascination is thought to be more with the process of experimentation and exploration of media than with an intended product. The drawing by a 21⁄2-year-old child in Figure 11-2 demonstrates how repetitious marks (in this case
The Development of Graphomotor Skills • 221
Figure 11-2
Scribbling marks with no representational intent (21⁄2-year-old boy).
circular) are employed in exploring the use of a drawing implement on paper. Only at the completion of these marks is a border introduced as a way of demarcation. Demarcating parts of a picture is argued to indicate the beginning of an interpretive phase, which occurs between the ages of 3 and 4 years. During this phase a child begins to interpret a drawing, but generally only after it has been produced. The representational intent is not there at the outset. For example, Figure 11-3 was drawn by a 31⁄2-year-old child. The task commenced with the scribbling at the top of the page with no apparent commitment as to the topic of the drawing. At the completion of the task the child was asked to talk about what had been drawn. The child nominated the descriptions that have been inserted in print but only after some reflection and consideration. In the next stage (4 to 5 years) the nature of the drawing is announced before its commencement, but the coordination of individual elements remains difficult. At this stage children label and sign their drawings (Devlin-Gascard, 1997). Words are incomplete and letters are often reversed, but the comprehension of symbol and meaning is observable. The drawing of a ship by a 41⁄2-year-old boy in Figure 11-4 demonstrates the use of word labels to describe the intent of the drawing. In this case it was to inform the viewer that the drawing was of the ship Oronsay, which had hit a rock and was badly damaged. The 6- to 7-year-old child is able to include all the characteristics of objects being drawn as they are known to him or her. This is not always consistent with
the way they are in an adult reality. Figure 11-5 demonstrates how a 6-year-old girl perceives her school. The drawing is not a realistic representation but it does contain features of her school and it highlights her understanding of a friendly environment. Finally, from around 8 years of age the child begins to take into account visual perspective; object position and orientation also become more important. This shift represents a progression from intellectual realism, in which the child draws what he or she knows about a stimulus, to a stage in which the drawing depicts what actually can be seen (Laws & Lawrence, 2001). This shift also has been associated with an increase in the amount of attention given to the object being drawn (Sutton & Rose, 1998), suggesting that realism is based on ability to attend to detail. The ability to produce and appreciate graphic perspective has received considerable attention (Freeman, 1980; Freeman, Eiser, & Sayers, 1977; Nicholls & Kennedy, 1992; Toomela, 1999). Some authors see the onset of perspective as evidence of cognitive maturation (Reid & Sheffield, 1990), whereas others argue that it is necessary to learn the rules about how to represent something in true perspective (Hagen, 1985; Orde, 1997). This latter view is based on studies that found little difference between the way in which children handle the three-dimensional plane and the methods adopted by adults. In both populations, individuals who have no special artistic talent or training reproduce the visual structures that they see in natural perspective along a continuum from orthogonal (no diminishing
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Rain
Big tree
Horse float
Horse 1 Baby in back seat
Jeep
Driver
Road
Figure 11-3
Figure 11-4
Beginning of interpretive phase. Naming occurs verbally at completion (31⁄2-year-old boy).
Labels incorporated into picture as a way of demonstrating intent (41⁄2-year-old boy).
The Development of Graphomotor Skills • 223
Figure 11-5
Figure 11-6
Objects drawn as perceived, not necessarily realistically (6-year-old girl).
Use of foreground and background, as well as three-dimensional perspective (8-year-old boy).
projected size with increasing distance) to projective (image size decreases as distance increases). As with other skills that have learned elements, Messaris (1994) argues that enhancement of depth perception might lead to a more general stimulation of the capacity for perceiving and thinking about three-dimensional space, an important component of general intelligence. Figure 11-6 demonstrates the use of foreground and background, as well as three-dimensional perspective. Some uniformity exists in the way certain objects are drawn. Both convention and handedness have been implicated in this uniformity (van Sommers, 1984). For example, right-handed people tend to commence
the drawing of a free-standing circle at around the 12 o’clock position and invariably draw counterclockwise, whereas a little more than 60% of lefthanded people draw a circle in a clockwise direction. Another interesting convention is the direction in which profiles are facing. Most profiles of faces, for instance, are drawn turned to the left, as are most cars. Glasses are drawn with the lenses to the left, pencils have points to the left, spoons and pipes have bowls to the left. On the other hand, most flags are drawn flying to the right, and cups and buckets have their handles to the right. The foundations for these uniformities have not been documented and neither have there been
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any reports located that explore the impact of left handedness on these tendencies. Children maintain individuality in their drawings of the most common objects even though they may have constant access to other children’s drawings. When children do adopt stereotyped formulas, they frequently include their own versions alongside. The drawings of one child over time may be very repetitious in the treatment of the same subject material (van Sommers, 1984). The logic is that flexibility of drawing is lost because of the repetition of early drawing strategies. This is not to say that children’s drawings never change but that they evolve by gradually modifying existing drawing strategies, rather than by a revolutionary rethinking of their basic representational strategy. Following this line of reasoning, innovation in drawing is thought to occur late in the sequence of producing a drawing and not in the initial strokes (van Sommers, 1984). There has been some discussion in the literature about the role of coloring-in and the development of children’s graphic skills (Duncum, 1995). Debate seems to surround the use of coloring-in as a means of developing pencil control as opposed to being part of artistic development. Coloring-in, or the use of pencils, crayons, or other implements to provide a color fill within a space defined by lines, is widely undertaken by children and is promoted by teachers, parents, and commercial enterprises (King, 1991). For example, it is employed for the purpose of product promotion for movies and by fast food outlets, and as a means of keeping children occupied when they are on plane trips. Further, proficiency of coloring-in is judged and rewarded as part of promotional competitions for various products. Distinction needs to be made about the use of coloring-in that is predetermined by the presentation of a figure and coloring-in that children choose to undertake after they have produced a drawing. The former, which opponents call “dictated art” (Herberholz & Hanson, 1985, p. 5), and place in the same category as paint-by-numbers, is thought to detract from appreciation of shapes and forms and their creation. Conversely, when children color-in their own creations they are more highly motivated and better able to adhere to the structures they create (Duncum, 1995). Jefferson (1969) proposed that coloring-in per se can be used as a means of improving fine motor skills associated with handwriting. This proposition has not been researched; therefore the practice, although widely adopted, seems to be based in convention more than research.
COMPUTERS AND DRAWING The production of pictures by young children using the computer is now quite a common practice. The
BUS A OW E N
JENNY MARK
Figure 11-7 Computer-generated drawing demonstrating spatial realism (6-year-old boy).
Figure 11-8 Computer-generated freehand drawing (6-year-old girl).
computer mouse is considered the most child-friendly interface for accessing a wide range of software (Lane & Ziviani, 1997). The mouse is used in a variety of ways depending on the nature of the program. The range of tasks required of a mouse to achieve the desired outcomes includes tracking, clicking, and dragging (Lane & Ziviani, 1999). As with drawing, producing computer graphics makes varying demands on visual motor control. There have been preliminary attempts to assess children’s skill proficiency using the mouse (Lane & Denis, 2000) but little documented about the spontaneous attempts of children to draw using a computer. Figures 11-7 and 11-8 are two examples of how children use this medium. The picture in Figure 11-7, by a 6-year-old boy, demonstrates many of the characteristics thought to manifest in pencil and paper drawings at this age. There is evidence of spatial realism with respect to the placement of the bus in relation to the road and the use of objects (i.e., helicopter) for
The Development of Graphomotor Skills • 225 scenic representation. The mouse functions of tracking, click, drag, and place have been used in this drawing. In another example of freehand drawing (see Fig. 11-8), a 6-year-old girl demonstrates the use of click and drag to create a self-portrait. There is scope for further research in this domain to examine comparability between the production of drawings using pencil and paper and computer software.
DRAWING AND DEVELOPMENTAL EVALUATION Children’s drawing ability is incorporated into a number of assessments of developmental status. The ability to reproduce a straight line, a cross, and a circle, for example, is used in a number of assessments as indicators of developmental maturity (Bayley, 1993; Folio & Fewell, 2000; Gesell, 1956; Griffiths, 1970). Furthermore one of the most widely used tests of visual-motor integration, The Developmental Test of Visual Motor Integration (VMI) (Beery, 1997) evaluates children’s accuracy in reproducing shapes to determine their visualmotor maturity. Some researchers have determined ability in this assessment as being directly related to subsequent handwriting skill (Oliver, 1990). A number of studies have associated the ability to draw a human form, such as found in the Goodenough Draw-A-Man Test (Goodenough, 1926) with a range of cognitive (Harris, 1963; Scott, 1981), behavioral (Hartman, 1972; Pope-Grattan, Burnett, & Wolfe, 1976), and emotional (Fu, 1981; Roback, 1968) characteristics in children. To date the findings from these investigations remain inconclusive. Other issues related to the perceptual-motor ability necessary to draw a human form, the gender variability in drawings of this nature, and the efficacy of drawing the self as opposed to a male or female form have been investigated (ShortDeGraff & Holan, 1992). Short-DeGraff and Holan found that factors in preschool children’s self-drawing were significantly and positively related to visual motor skills as measured by the Test of Visual Motor Skills (Gardner, 1986) but not with a measure of verbal intelligence. Short-DeGraff and Holan also explored alternatives to scoring the drawing to those originally proposed by Goodenough. The high association between their simplified scoring methods and Goodenough’s more complex methods suggests that simplification of scoring criteria is possible. Further research of the scoring criteria, as well as extending the ages of children under investigation, is warranted based on these preliminary findings. Obviously, for those children with motor impairment (e.g., cerebral palsy, spina bifida) the quality of drawings may be affected. The differences between their drawings and those of children without disability
should be considered within the context of the child’s perceptual-motor limitations, cognitive impairment, and possible environmental restrictions. Determining the relative contribution of each factor is not easy. Unfortunately, many assessments of developmental and cognitive abilities rely, in part, on copying abilities, especially for preschool children (Moore & Law, 1990). An attempt has been made by Reid and Sheffield (1990) to accommodate perceptual-motor limitations when examining children’s drawings. These authors adopted a cognitive-developmental model for the analysis of drawings in children with myelomeningocele. Reid and Sheffield argue that instead of attending to the quality of drawings, which may be detrimentally affected by motor disability, the subject matter and its depiction should become the focus for determining developmental maturity. They propose four complex stages through which children pass in the development of mature drawings. Perspective plays an important part of their conceptualization of a mature drawing. Preliminary observations suggest that Reid and Sheffield’s stages and conceptualization of the content of drawings are a useful analytic scheme for children with myelomeningocele. However, other experimenters argue against the developmental significance of perspective (Bremner & Batten, 1991; Hagen, 1985). Further research to examine the potential clinical utility of Reid and Sheffield’s (1990) findings, especially in the more complex final stages of their model, is warranted. A view of unique developmental progression in the drawing ability of children with Down’s syndrome has been advanced by Laws and Lawrence (2001). They found preliminary evidence that the spatial characteristics of drawings of children with Down’s syndrome may follow an alternative route to those of children without Down’s syndrome because of problems related to motor planning, motor weakness, and aspects of language development. Children with Down’s syndrome in their study did follow the expected developmental, albeit delayed, trajectory of children in the control group. Yet there were elements in the drawings of children with Down’s syndrome that attested to their ability to account for aspects such as spatial relationships, although not in the same way as children without Down’s syndrome. However, the two groups were comparable with respect to drawing detail. The authors of this study join others (Eames & Cox, 1994) in advocating the use of measures sympathetic to children with different developmental profiles. This section has discussed the development of drawing and the expectations of the composition of drawings for typically developing children. It has shown the importance of considering the different ways that children with special needs may interact with writing implements and develop their drawing competence. The
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following section focuses on a different graphomotor skill, that of handwriting.
HANDWRITING HANDWRITING AND WRITING: COMPLEMENTARY CONCEPTS There is an important differentiation, but also relationship, between handwriting and writing. Handwriting refers to the process of transcribing letters to form words and words to form sentences. Writing, on the other hand, is the composition and content of the material that is handwritten. Proficient writing relies on well-developed handwriting skills. Jones and Christensen (1999), for instance, reported that handwriting skills accounted for 50% of the variance in the quality of writing content in a sample of 6- and 7year-old students. Both handwriting and writing are complex abilities that are acquired hand-in-hand with children’s acquisition of language. As with drawing, the foundations for both handwriting and writing are the integration of intrinsic and extrinsic factors. Extrinsic factors involved in handwriting include instruction in handwriting, the quality and extent of practice undertaken, the requirements of the task, and the materials used. Intrinsic abilities include orthographic coding, orthographic-motor integration, visual-motor skills, fine motor skills, cognition, linguistic skills, and motivation (Tseng & Chow, 2000). Orthographic coding involves developing a visual representation of letters and words, knowledge of the process of forming each letter, a verbal label for each letter, an accurate representation of the letter’s form in memory and the ability to access and retrieve this information from memory (Edwards, 2003; Jones & Christensen, 1999; Weintraub & Graham, 2000). Orthographic-motor integration is the way in which this letter knowledge can be motorically transcribed to form letters and words on paper. Writers who have poor orthographic coding and ortho-motor integration, and thus need to attend to the mechanics of handwriting (e.g., letter formation, spacing, alignment), have less attention and working memory that can be directed to composing written work and spelling, monitoring, and revision of the written work (Edwards, 2003; Swanson & Berninger, 1996). Children’s competence in writing depends, in part, on the mastery of handwriting (Graham, Harris, & Fink, 2000). The ability to write legibly and in a timely fashion is necessary for children to adequately document their knowledge and learning. Children’s documentation is largely the basis on which their knowledge acquisition is judged. Research has shown that lower
marks are ascribed to work that is less legible even when the content is the same as more legible work (Graham, Weintraub, & Berninger, 2001). Children with handwriting difficulties may avoid writing, or the effort involved in the process of handwriting may impede the ability to generate text that adequately reflects their knowledge. Handwriting difficulties are a significant problem for educationalists and occupational therapists. Berninger and co-workers (1997), for instance, identified 202 (29%) at-risk writers out of 685 children screened and another study identified 24% of children in a sample of 798 kindergarten and grade 1 children as having poor handwriting (Harris & Livesay, 1992). Further, a survey of grade 1 to 4 teachers reported that 23% of children had handwriting difficulties (Hammerschmidt & Sudsawad, 2004). Handwriting proficiency remains a fundamental educational goal despite the availability and uptake of computer technology. The focus of this section is on understanding handwriting as a basis for intervention.
THE DEVELOPMENTAL NATURE OF HANDWRITING Several features of handwriting development are consistent from both historical and cross-cultural perspectives. At least some characteristics of handwriting are likely to be common across cultures, language, and written script (Yochman & Parush, 1998). For example, there is a developmental progression of both speed and legibility of handwriting with age and a relationship between visuomotor skills and handwriting. Also girls tend to write faster and more legibly than boys and more boys than girls have handwriting difficulties. Further, about 10% of a population is left handed but left handedness is not associated with illegibility or slower speed of handwriting. These relationships have been relatively consistent in studies of handwriting of English, Chinese, Hebrew, and Norwegian children (Graham, 1998; Karlsdottir, 1996; Tseng & Cermak, 1993; Tseng & Chow, 2000; Yochman & Parush, 1998). There are also consistent factors that seem to operate in the development of written script over time: The size of the writing diminishes; letter formation, spacing, and horizontal alignment become more accurate, simplified, and standardized; the handwriting may become abbreviated; and cursive forms evolve with curves replacing angles and ligatures joining letters (van Sommers, 1991; Yochman & Parush, 1998). Children personalize their own style of handwriting as formal handwriting instruction diminishes. The personalized style generally is faster and more efficient, which may result in a deterioration of letter formation at times. Personalized handwriting tends to become a mix of manuscript and cursive letters, which develops
The Development of Graphomotor Skills • 227
BOX 11-1
1. 2. 3. 4. 5. 6. 7. 8. 9.
The First Nine Forms of the Developmental Test of Visual Motor Integration in Order of Increasing Difficulty
Vertical line Horizontal line Circle Cross Right oblique line Square Left oblique line Oblique cross Triangle
Beery KE (1989). The Developmental Test of Visual-Motor Integration, 3rd rev. Cleveland, OH, Modern Curriculum Press.
because it is faster than exclusively manuscript or cursive. Mixed handwriting that is predominantly cursive is used relatively less frequently than other forms (cursive, manuscript, or mixed but mostly manuscript). Despite this, mixed handwriting that is mostly cursive tends to yield more legible handwriting (Graham, 1998). Integral to the issues of handwriting development and understanding the developmental expectations for handwriting is the question of when young children are ready to begin handwriting instruction. A number of factors may be considered here: perceptual readiness, linguistic readiness, and the maturity of pencil control. Beery (1989) argued that young children are not ready to learn handwriting until they can correctly copy the first nine forms of the VMI (Beery, 1989) (Box 11-1). Kindergarten children who can copy these forms also can copy significantly more letters (Daly, Kelly, & Krauss, 2003; Weil & Cunningham Amundson, 1994) and have better handwriting in grade 1 (Marr & Cermak, 2002) than children who cannot achieve nine forms. Daly demonstrated that 56% of children, when tested in the first quarter of the kindergarten school year, were able to copy these nine forms. This compares with 88% who copied the nine forms in the middle of the kindergarten school year in Weil and Cunningham Amundson’s study. Thus if using the VMI as an indicator of handwriting readiness, most typically developing kindergarten children should be ready to succeed with handwriting instruction in the latter half of the kindergarten school year. As children develop the skill of handwriting, their performance changes both qualitatively and quantitatively. Handwriting quality and quantity translate, respectively, into legibility and speed. How do we judge if either or both of these aspects are appropriate for the
child’s chronologic or developmental level and what factors constitute handwriting dysfunction? Handwriting difficulties become apparent when children write too slowly to record sufficient quantities of work or when the written work is difficult to read. For instance, teachers report that failure to read student handwriting was the most important criteria in determining whether a child had handwriting difficulty (Hammerschmidt & Sudsawad, 2004). Poor handwriters are more likely to have inadequate closure and line quality of letters, poor orientation to the writing line, poor spacing between words and letters within words, and inconsistent sizing of words and of letters within words (Malloy-Miller, Polatajko, & Anstett, 1995). Although children with handwriting difficulty should be seen within their social and educational contexts, general developmental expectations do exist. One study documents the grade level expectations of children between 7 and 14 years of age in terms of handwriting size, horizontal alignment, spacing consistency, and letter formation (Ziviani & Elkins, 1984). Drawn from a population of Australian schoolchildren, these data support the assumption that letters become more accurately formed, spacing becomes more consistent, size diminishes (more particularly in girls), and handwriting attains better horizontal alignment. Information about developmental expectations and the factors contributing to handwriting illegibility provide a useful baseline measure for children exposed to similar educational instruction. Ziviani, Hayes, and Chant (1990) used the normative data discussed previously to help specify the nature of difficulties experienced by children with spina bifida who were able to attend regular schools. Their findings indicated that speed, horizontal alignment, and letter formation were the handwriting characteristics most detrimentally affected. Meanwhile, handwriting size fell within two standard deviations of the normative means, and spacing consistency often was better than in the normative sample. Such findings are useful in delineating handwriting dysfunction to target intervention and not just accepting a global disability. Handwriting quality appears to be an elusive concept to measure despite the development of both global and detailed handwriting assessments. A review of frequently used handwriting tools was written by Feder and Majnemer (2003). A global measure such as the Test of Legible Handwriting (TOLH) (Larsen & Hammill, 1989) compares the individual’s performance with a series of model specimens and the important consideration in scoring is overall legibility (Feder & Majnemer, 2003). However, researchers have sought increasingly to break down handwriting samples into their component parts and over the years a wide variety of handwriting scales (Amundson, 1995; Phelps,
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Stempel, & Speck, 1984; Reisman, 1993; Stott, Moyes, & Henderson, 1985; Ziviani & Elkins, 1984) and checklists (Alston, 1985) have been produced to reflect this approach. Most of these tools identify characteristics considered to contribute to handwriting legibility. In general, the handwriting characteristics specified in these detailed tools can be classified as giving form (letter legibility and formation, size) or spatial alignment (space between letters and words, alignment with lines) to handwriting. These tools provide a more comprehensive way of understanding legibility difficulties than global handwriting assessments and offer a basis for designing appropriate remedial interventions. Graham, Weintraub, and Berninger (2001) reported that several factors were significantly related to good overall text legibility. These factors include letter legibility, the absence of additional lines or strokes attached to letters, correct within-letter proportions, correct letter formation, and no rotations of letter parts. There are other factors, arguably overlooked, that relate to movement and that contribute to handwriting legibility (e.g., pressure while handwriting, frequency of pen lifts). Of all the elements, individual letter legibility (which incorporates letter formation, proportion, and shaping, and letter identification out of the context of a word) is considered the most important to overall text legibility (Graham et al., 2001; Mojet, 1991). Handwriting speed is not necessarily related to legibility; that is, handwriting speed is not predictive of legibility and vice versa (Wann, 1987; Weintraub & Graham, 1998). There is a trade-off, however, between handwriting speed and legibility when children are
Table 11-1
specifically asked to write neatly or quickly. Children asked to write neatly, for instance, do so at the expense of speed; and children’s legibility decreases when asked to write more quickly (Weintraub & Graham, 1998). Authorities differ in terms of expected handwriting speeds for children at various ages. A summary is presented in Table 11-1. Most variation in handwriting speed normative information may be attributed to differing test instructions (“write normally” versus “write fast”). In appraising handwriting speed tests and their relevance to assessing handwriting speed, consideration needs to be given to the nature of the text being written (whether it is copied or self-generated), the timing of data collection in the school year, and variation in teaching practices. We know that the speed of handwriting slows and that legibility and the quality of letter formation decrease over a lengthy handwriting sample in both good and poor handwriters (Dennis & Swinth, 2001; Parush et al., 1998a). Fatigue affects handwriting; therefore the length of text used to evaluate handwriting speed and legibility and its relationship to everyday writing tasks needs to be considered. Further work on tests of handwriting speed is necessary to update and validate findings. Standardized data used to evaluate handwriting ability and compare performance with norms should reflect the child’s cultural and educational environment. Teachers’ observations within a peer-appropriate context are critical when deciding if a child’s performance is within developmental expectations. Teachers are accurate in categorizing children with and without handwriting difficulties when compared with a standardized assessment of handwriting ability (Cornhill & Case-Smith, 1996).
Reported mean handwriting speed (letters per minute) by school grade
Author
3
Groff (1961)
4
School Grade 5 6
35.1
40.6
49.6
Hamstra-Bletz & Blote (1990)
25
37
47
57
Phelps, Stempel, and Speck (1985)
35
46
54
66
Sassoon, Nimmo-Smith, and Wing (1986)
7
62
64
Wallen, Bonney, and Lennox (1996)
54.2
57.1
63.8
80.7
94.2
Ziviani and Elkins (1984)
32.6
34.2
38.4
46.1
52.1
The Development of Graphomotor Skills • 229
FACTORS CONTRIBUTING TO HANDWRITING PERFORMANCE Effective intervention can be planned when the factors affecting an individual child’s ability to complete legible and timely handwriting are clearly understood. In addition to changes to handwriting legibility and speed that occur over time in children’s handwriting, various constraints to handwriting acquisition operate at different stages of development. Berninger and Rutberg (1992) suggest that neurodevelopmental constraints in orthographic coding, fine motor function, and orthographic-motor integration are likely to interfere with the rapid automatic production of written language in younger children. Later, when most children can automatically write the alphabet and spell a set of functional words, the writing process is more probably constrained by verbal working memory and ability to generate the major units of written language—the word, the sentence, or text-level structures. Once proficiency in generating units of language is achieved, writing can be constrained by cognitive processes such as planning, translating, and revising when composing larger pieces of text. For older children constraints may still be operating at the neurodevelopmental or linguistic, as well as the cognitive levels. Inefficiencies in the low-level neurodevelopmental processes early in handwriting acquisition can contribute to future higher-level writing disabilities, both directly (because production of written material continues to be a problem) or indirectly (because of an aversion to writing arising from early frustration and failure) (Berninger et al., 1997). Some of the major factors implicated in handwriting performance follow.
Working Memory Swanson and Berninger (1996) demonstrated that individuals have a unique working memory. Working memory is the ability to temporarily retain information during the processing of other information. During handwriting, orthographic codes are retrieved from long-term memory and held in working memory while the writer is developing the text (Weintraub & Graham, 2000). More processing functions are available for idea generation, translation, and sequencing of ideas to text, and revision of writing when aspects of handwriting (including orthographic skills and even punctuation) are automatic (Jones & Christensen, 1999). Further, ideas that are held in working memory may be lost if a child needs to focus attention on the mechanics of forming a letter (Graham et al., 2001). Evidence for this derives from studies that have shown a relationship between orthographic-motor integration and written expression and have demonstrated that writing (written
expression) improved after intervention that specifically targeted orthographic-motor integration by teaching correct and automatic letter formation (Berninger et al., 1997; Graham, Harris, & Fink, 2000; Jones & Christensen, 1999). An essential educational goal is to provide handwriting instruction that develops automatic, fluent handwriting to free working memory for writing; that is, generating ideas, monitoring, and revising content (Berninger et al., 1997).
Handwriting Instruction Handwriting is heavily influenced by the nature of the instruction received and the extent of practice undertaken by the individual. In fact, the main factor that influenced legibility in a study by Lamme and Ayris (1983) was the great variability in handwriting instruction provided by the teachers involved in the study. Handwriting probably receives insufficient emphasis in school curricula: Teachers (62% of sample) reported that they would like to spend more classroom time on handwriting instruction (Hammerschmidt & Sudsawad, 2004). Berninger and co-workers (1997) surveyed teachers who reported that students were becoming less proficient at handwriting when they reached year 1 than students of previous years. The importance of focused handwriting instruction to both legible handwriting and writing has been demonstrated in a number of studies (Berninger et al., 1997; Graham et al., 2000; Jones & Christensen, 1999; Jongmans et al., 2003; Karlsdottir, 1996). Important components to include in handwriting instruction are listed in Box 11-2 (Berninger et al., 1997; Graham et al., 2000; Hayes, 1982; Jones & Christensen, 1999). It seems that providing more types of cues or perceptual prompting of letter formation may result in better outcomes. Adi-Japha and Freeman (2001) found that by 6 years of age children’s writing and drawing systems were differentiated. Children as young as 3 years of age produce different scribbles when asked to write their name than those scribbles generated when drawing a picture (Haney, 2002). Writing-specific cortical routes emerge probably as a result of practicing handwriting. Writing within a script context (e.g., words and letters on a page) rather than writing within a picture context produced more fluent handwriting (Adi-Japha & Freeman, 2001). The importance of handwriting practice in early learners and thus a differentiation and specialization of writing is reinforced by these findings. Further, consideration needs to be given to the teaching and practice of handwriting within writing specific contexts; that is, using dedicated writing implements and books, and reducing drawing conditions when the aim is handwriting proficiency. Working within a script context activates the writing system, and activation of
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BOX 11-2
Important Components to Include in Handwriting Instruction
• Copying model letters • Visual directional cues provided by arrows • Verbal prompting of letter formation (both instructor and self-verbal prompting) • Copying from memory • Reinforcing letter names and practice of letters with a focus on committing these to memory Berninger VW, Vaughan KB, Abbott RD, Abbott SP, Rogan LW, Brooks A, Reed E, Graham S (1997). Treatment of handwriting problems in beginning writers: Transfer from handwriting to composition. Journal of Educational Psychology, 89(4):652–656; Graham S, Harris KR, Fink B (2000). Is handwriting causally related to learning to write? Treatment of handwriting problems in beginning writers. Journal of Educational Psychology, 92(4):620–633; Hayes D (1982). Handwriting practice: The effects of perceptual prompts. Journal of Educational Research, 75(31):169–172; Jones D, Christensen CA (1999). Relationship between automaticity in handwriting and students’ ability to generate written text. Journal of Educational Psychology, 91(1):44–49.
the writing processing system separately from a drawing context prepares for more accurate and automatic handwriting output. The outcomes of the studies that have focused on developing orthographic skills and automatic handwriting have all been positive. The results suggest that poor letter knowledge and orthographic skills are major contributors to handwriting difficulties and are essential to consider in handwriting intervention. Other studies provide useful information to consider when planning handwriting intervention. One study examining the ability of children in years 1 to 3 to write manuscript letters reported that some letters were more difficult to form legibly (Graham et al., 2001). Overall these letters, in descending order of difficulty, were q, z, u, j, k. Fortunately some of these letters are not frequently used in handwriting but may require more focus during handwriting instruction and should be introduced only after mastery of easier letters. Despite ongoing debate, it seems that teaching slanted or elliptical manuscript does not have advantages over traditional manuscript in legibility outcomes or assisting the transition to cursive handwriting (Graham, 1998). Karlsdottir (1996) showed that handwriting quality of older (10-year-old) students was significantly enhanced by reintroducing each letter form with accompanying visual and verbal cues. Thus one should consider these orthographic factors even in more mature writers. Older writers also tend to personalize handwriting by mixing manuscript and cursive text, among other things. Generally this is to
the advantage of both speed and legibility and need not be discouraged. Factors That Influence the Effectiveness of Handwriting Instruction Factors such as kinesthesis, fine motor skills, and visual motor abilities are associated with handwriting development and performance (Weintraub & Graham, 2000). Researchers exploring these factors operate under the assumption that they underlie handwriting performance and that understanding their relationship with handwriting assists with developing and evaluating intervention programs (Tseng & Cermak, 1993). Further factors, such as posture while handwriting, paper positioning, and stabilization of paper, as well as other ergonomic factors, discriminate good and poor handwriters (Parush, Levanon-Erez, & Weintraub, 1998b). Posture and stabilization anomalies may result from similar mechanisms to those that cause handwriting difficulties. It is not yet known whether remediating kinesthesis, fine motor, visual motor, ergonomic, and other factors improve handwriting output and writing outcomes. Issues in relation to motor execution specific to handwriting were introduced in the earlier section on the processes of acquisition of graphomotor skills and are expanded here. When an orthographic code is mobilized from memory for handwriting, a motor program is executed that encompasses manipulating a writing implement to form letters and words (Weintraub & Graham, 2000). Two aspects of motor execution are examined in the literature, fine motor skills (including in-hand manipulation) and abilities related to kinesthesis. Isolated and graded finger movements are necessary to provide precise and rapid manipulation of a writing tool for handwriting. On the basis of this premise, fine motor skills and in-hand manipulation are frequently assessed as part of a handwriting assessment. Fine motor skills are assessed globally by tools such as the Peabody Developmental Motor Scales—Fine Motor (Folio & Fewell 2000). Fine motor skills incorporate the basic patterns of reach, grasp and release, and the more complex skills of in-hand manipulation and bilateral hand use (Exner, 1989). In-hand manipulation, then, is an essential component of dexterous hand function and can be assessed separately using tools such as those developed by Exner (1993) or Case-Smith (1995). These assessments include some of the defined features of in-hand manipulations such as rotation (e.g., turning an object over using the fingers of one hand) and translation (e.g., using the fingers of one hand to move objects in and out of the palm). In-hand manipulation is assessed as its own entity in handwriting evaluation because of a perceived relationship to pencil manipulation. In reality the association between fine motor skills
The Development of Graphomotor Skills • 231 or in-hand manipulation and pencil grip and handwriting speed and legibility has not been extensively explored. Rubin and Henderson (1982) found that children with poor handwriting did not have significantly different scores from a group of good handwriters on the Test of Motor Impairment, but they did have more variability of their scores. Tseng and Chow (2000) on the other hand, found that Chinese handwriters, categorized as slow writers by their teachers, had significantly lower scores on the Upper Limb Speed and Dexterity subtest of the Bruininks-Oseretsky Test of Motor Proficiency than normal speed handwriters. Cornhill and Case-Smith’s work (1996) provides us with some evidence that in-hand manipulation is a significant predictor of handwriting legibility. Their sample of year 1 students with handwriting difficulties had significantly lower in-hand manipulation scores than fellow students with good handwriting. Still we do not know whether improving fine motor and in-hand manipulation ability results in more legible or faster handwriting. Debate continues about the role of kinesthesis in handwriting performance and the effectiveness of kinesthetic training in improving handwriting. Laszlo and Bairstow (1985b) have argued, based on their work with the KST, that kinesthetic memory, more than kinesthetic acuity, is primarily responsible for the skilled performance of writers. Studies investigating the proposed relationship between training children using the testing equipment of the KST and handwriting performance have reported contradictory findings and have cast a shadow on the psychometric properties of the KST (Hoare & Larkin, 1991; Lord & Hulme, 1987). Two of the stronger studies provide the best evidence that the KST is not associated with handwriting. Copley and Ziviani (1990) found no significant relationship between the KST and handwriting quality when testing good and poor handwriters. A welldesigned randomized controlled trial evaluated handwriting outcomes after kinesthetic training on the KST equipment (Sudsawad et al., 2002). There were no significant between-group differences in these grade 1 children after kinesthetic training compared with a sham intervention and no intervention. Previous studies have evaluated kinesthetic training in children with poor handwriting without identifying whether or not they had kinesthetic difficulties. An important difference of Sudsawad’s study from previous ones is that the children recruited were identified as having handwriting difficulty, as well as kinesthetic impairment identified by the KST. The evidence suggests that kinesthetic training using the KST equipment is not an effective handwriting intervention. Research on other aspects of somatosensory ability and handwriting are inconclusive. Weintraub and Graham
(2000) found that “finger function” was a strong predictor of good or poor handwriting ability. Rather than reflecting strictly fine motor ability, the finger function tasks contained largely proprioceptive and somatosensory ability. Yochman and Parush (1998), however, found no correlation between kinesthesia-related tests and handwriting performance. Visual motor integration appears to be an important factor in handwriting legibility. A great deal of research supports the assumptions that (a) visual motor integration is correlated with handwriting performance in good, as well as poor handwriters (Tseng & Chow, 2000; Tseng & Murray, 1994; Weil & Cunningham Amundson, 1994); (b) visual motor abilities are weaker in children with handwriting difficulties, across a wide range of ages, compared with children without handwriting difficulties (Cornhill & Case-Smith, 1996; Daly, Kelly, & Krauss, 2003; Rubin & Henderson, 1982; Tseng & Chow, 2000; Tseng & Murray, 1994); and (c) visual motor integration difficulties are a predictor of handwriting legibility (Cornhill & Case-Smith, 1996; Maeland, 1992; Tseng & Chow, 2000; Weintraub & Graham, 2000; Yochman & Parush, 1998). Visual motor integration may be particularly important in the acquisition of handwriting because visual motor abilities are used to acquire orthographic coding skills. Occupational therapists tend to view visual motor integration as underlying handwriting dysfunction and intervene using visual motor activities (Case-Smith, 2002). Despite this relative abundance of evidence confirming the relationships between visual motor integration and handwriting, there is as yet no evidence that remediating visual motor skills will result in enhanced handwriting output. Handwriting intervention studies in the educational and motor learning literature focus on developing orthographic coding and using self-instruction methods for enhancing handwriting legibility and writing ability (Berninger et al., 1997; Graham et al., 2000; Hayes, 1982; Jones & Christensen, 1999; Jongmans et al., 2003; Karlsdottir, 1996). These studies provide good evidence that these approaches are effective in enhancing various aspects of handwriting legibility and speed and also the content of written work. Studies in occupational therapy are fewer in number than studies in education. Typically occupational therapy intervention studies integrate multiple theoretical perspectives and offer broad-based interventions encompassing biomechanical, multisensory, visual motor, fine motor, and handwriting-specific interventions (Case-Smith, 2002; Lockhart & Law, 1994; Peterson & Nelson, 2003). A range of outcomes which are not always related to handwriting legibility, speed, and content are evaluated. Two such broad-based studies (including one randomized controlled trial) reported significant improvement in handwriting; however, the specific components of the intervention that contributed
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to the outcomes are undetermined (Case-Smith, 2002; Peterson & Nelson, 2003).
COMPUTERS AND HANDWRITING Children with significant disability or those who continue to have handwriting difficulties even after intervention may consider word processing as an alternative. There are a multitude of factors to consider in deciding whether keyboarding is an appropriate strategy for children to adopt. Just some of these factors are the keyboard configuration (e.g., laptop, PC); software (e.g., word prediction); transfer of data among home, school, and printers; the cognitive demands of managing files, academic subjects, and the facilities of multiple software packages; the physical demands of the task; and the suitability to the child. Further, it is necessary to predict whether a child will actually achieve quality written expression with adequate accuracy and speed compared with handwriting. Keyboarding, like handwriting, is a complex skill and requires many hours of practice to achieve proficiency. Learners of keyboarding should progress through stages of learning the position of keys and the various movement patterns necessary to achieve correct key strokes. Proficiency, which relies largely on kinesthetic feedback and little on visual feedback, may be achieved with practice. It is interesting to contemplate whether handwriting and keyboarding have similar underlying abilities. If so, and if handwriting is a difficulty, then these same underlying abilities also may affect the development of proficiency at keyboarding. Studies indicate that different components underlie handwriting and keyboarding accuracy in typically developing students (Preminger, Weiss, & Weintraub, 2004; Rogers & Case-Smith, 2002). This information combined with Barrera, Rule, and Diemart’s (2001) finding that year 1 students wrote more words and sentences using a keyboard than handwriting gives us more confidence in using keyboarding as an option for children with handwriting difficulties. Word processing and word prediction software can increase the legibility and spelling of written work in children with learning and handwriting difficulties (Handley-More et al., 2003). Studies do not concur as to whether keyboard instruction can result in keyboard speeds that are faster than handwriting (Rogers & Case-Smith, 2002). Indeterminate hours are spent learning and refining handwriting. The expectation should be that substantial effort goes into ensuring that the speed and accuracy of keyboarding is at least equivalent to handwriting to make it a viable alternative to handwriting. The secondary complications of poor handwriting (e.g., compositional difficulties, avoidance of handwriting, and loss of confidence) may be avoided if
children can be offered word processing as a viable option to handwriting at an appropriate time (Rogers & Case-Smith, 2002). This review of handwriting has discussed handwriting development and factors associated with skilled handwriting execution. The fact that handwriting underlies quality written output and thus that good handwriting instruction is essential has been emphasized.
SUMMARY The process and products of children’s drawing and handwriting have intrigued occupational therapists, as well as others interested in child development, for a number of years. It is clear from this chapter that, although we now have certain structures in place to understand the developmental transitions in children’s drawings, there is still much to understand. The same can be said for handwriting. There remain aspects of drawing and handwriting acquisition that still tantalize; this chapter concludes by pointing to some issues that still beg investigation. Drawing is an important developmental experience for children. With the increasing use of computers by younger and younger children, some of the pencil and paper drawings with which we are most familiar are being accomplished using a computer. Are we able to translate our knowledge of paper-based outcomes to those on the screen? Preliminary research has indicated that handwriting and keyboarding have differing underlying components. Thus we are unlikely to be able to translate our knowledge of handwriting directly to keyboarding. A greater understanding of word processing, as an alternative form of recording work, is necessary to match it to the individual needs of students. Using a motor learning framework, we understand that handwriting is a learned motor task requiring interplay among the writer, the task, and the environment. A key environmental factor in its acquisition is the quality of instruction received and amount of practice undertaken. However, even in the presence of adequate instruction there are a multitude of factors pertinent to an individual that may affect the child’s ability to develop handwriting. The association between some of these factors and handwriting has been better researched than others. For example, we know there is an association between visual motor integration and handwriting. We are less certain of the relationship between other factors such as kinesthesia and in-hand manipulation and handwriting. Cognitive, linguistic, and motivation factors also should inform research in this field. We require a better understanding of the
The Development of Graphomotor Skills • 233 relationship of all these factors to handwriting and especially how these factors are manifesting in children with poor handwriting. It may be that a breakdown in any of these factors may impede a child’s acquisition of handwriting. Determining their relative effect on performance is essential if appropriate intervention is to be designed. Developing proficient handwriting requires children to learn and apply a number of rules, as well as to develop motor programs for the efficient execution of script. We have established that the nature and extent of instruction are highly influential in proficient handwriting output. Part of handwriting instruction is knowing how to form individual letters and join them to manufacture words. One area that has not received much attention in the literature is the influence of different scripts in the attainment of proficient handwriting. The relative merits of learning print (ball and stick) and then moving on to learn cursive handwriting, as opposed to starting with a simple modified cursive script, also requires further investigation. Both approaches, in fact, are currently used in school systems throughout the world. We simply do not know which is more effective in optimizing handwriting development and outcomes. Research in the area of implement grasp and manipulation suggests that the type of grip being used need not necessarily impede handwriting speed and legibility (Dennis & Swinth, 2001; Koziatek & Powell, 2003). This suggests that the mechanism for execution of handwriting is less important than the cognitive, perceptual, and planning components. Research is needed to clarify this relationship. This review of the development of drawing and handwriting shows a field dotted with light and shade. Our knowledge of drawing and handwriting, grounded in research and founded on principles of motor learning, is the “light” we shed on our interactions with children with handwriting difficulties. The “shade” relates to areas in which knowledge is sparse. We should continue to seek knowledge that will shed light on the many “shaded” areas that currently exist in this area and will enable us to provide evidence-based and effective intervention for our clients.
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Chapter
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INTERVENTION FOR CHILDREN WITH HAND SKILL PROBLEMS Charlotte E. Exner
CHAPTER OUTLINE FRAMEWORKS FOR INTERVENTION WITH CHILDREN WHO HAVE HAND SKILL PROBLEMS Impact of Hand Skill Problems on Children’s Occupational Performance Intervention Approaches: Modifications or Adaptations and Motor Skill Remediation Factors to Consider in Intervention Planning GOAL SETTING FOR HAND SKILL INTERVENTION Considerations in Setting Goals Short-Term Goals for Hand Skill Intervention RESEARCH RELATED TO HAND SKILL INTERVENTION INTERVENTION STRATEGIES FOR HAND SKILL PROBLEMS Positioning of the Child and the Therapist Tactile or Sensory Awareness or Discrimination Tone and Postural or Proximal Control Isolated Arm and Hand Movements Grasp Voluntary Release In-Hand Manipulation Bilateral Hand Skills Integration of Skills into Occupational Performance ADJUNCTS TO DIRECT INTERVENTION: SPLINTING, CASTING, AND CONSTRAINT-INDUCED MOVEMENT THERAPY Splinting Casting Constraint-Induced Movement Therapy SUMMARY
FRAMEWORKS FOR INTERVENTION WITH CHILDREN WHO HAVE HAND SKILL PROBLEMS I MPACT OF HAND SKILL PROBLEMS ON C HILDREN’S OCCUPATIONAL PERFORMANCE Hand function has great significance for occupational performance. The greater the difficulties with hand function, the greater the impairment in skills that allow for independence and participation in academic and social activities. Children with hand function difficulties usually are limited in their ability to effectively or efficiently complete daily life skills and develop skills that will support optimal occupational performance in the future. In addition, for some children even subtle difficulties with hand skills may affect their social participation because of limitations in ability to engage in activities with their peers or messiness in task completion. Fine motor skills have a major impact on children’s school performance. McHale and Cermak (1992) found that “all the classrooms observed [in their study] had a high level of fine motor demands,” with fine motor tasks being carried out for 30% to 60% of the classroom day and the majority of these tasks involving writing activities. In preschool settings, children must be able to manage the classroom manipulatives, including puzzles, scissors, crayons, blocks, pegs, and beads. Elementary school-age children must be able to manage the entire writing process, which includes handling a pencil or pen effectively, using an eraser, tearing and folding paper, putting paper into notebooks and folders, and doing art projects. As children
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reach middle school and high school age, they not only have a high volume of written work, but they also take courses that have labs (e.g., science, industrial arts, home economics) that require the ability to handle small materials with dexterity. Children of all ages need effective hand function to manage eating, dressing, hygiene care, and a variety of other self-care activities independently in multiple environments. Expectations for independence, and therefore proficient hand use, increase throughout adolescence. Chapter 10 provides a thorough summary of the interaction of hand and self-care skills. In response to the frequent difficulties that children show and the impact of these difficulties on occupational performance, pediatric occupational therapists typically address children’s hand skills. Swart et al. (1997) report that intervention for fine motor skills is a top occupational therapy priority in working with children. In their study of approximately 200 pediatric occupational therapists, intervention for fine motor issues was rated as very important or important by 100% of the therapists. Almost 100% of these therapists reported that they consistently or often provide services that address fine motor issues, and at least 90% reported that addressing fine motor issues is unique or very unique to the profession of occupational therapy.
I NTERVENTION APPROACHES: MODIFICATIONS OR ADAPTATIONS AND MOTOR SKILL REMEDIATION A child’s hand function difficulties always must be placed within the context of the child’s overall functioning, needs, and priorities. Despite the significance of hand skills to occupational performance and social participation, the decision about intervention for hand skill difficulties must be made with the child (when feasible) and the family or other key individuals, keeping in mind the child’s overall needs and priorities and the likelihood of intervention having a significant impact on the child’s functioning. For example, a child may have multiple need areas for intervention, such as academic skills, mental health issues, or language difficulties. In addition, within the scope of responsibilities of the occupational therapist, issues of hand function may be of lesser priority than other areas, such as sensory regulatory issues, acquisition of independence in life skills, or psychosocial concerns. Thus the occupational therapist participates with the child, the family, and other team members in determining if and when intervention with a focus on hand function issues is in the best interest of the child. Two general types of intervention approaches may be considered in addressing hand function issues: adaptations
and direct intervention for the motor skill difficulty. However, these two approaches may be blended and both should be used with a consideration for applicability to the child’s occupational tasks. The Occupational Therapy Practice Framework (2002) is helpful in considering a variety of dimensions related to the intervention approach.
Modifications and Adaptations for Hand Skill Problems Within the Context of Occupational Tasks This type of intervention includes the use of alternative strategies for accomplishing tasks, including the use of adaptive equipment when necessary. Splinting is a common adaptation used to support hand function in children with moderate to severe disabilities. Although direct intervention may not appear to be crucial when adaptive strategies or splinting are selected as the primary method of intervention, children often need substantial intervention for these strategies to be used successfully. Family members or teachers may need ongoing guidance and the adaptive strategy or splint may need modifications for function and optimal use. The success of this type of intervention often is linked to the follow-up provided to insure that the child and others are using the strategy and are satisfied with the adaptation and its applicability to the child’s daily life task performance.
Motor Skill Remediation Within the Context of Occupational Tasks The therapist may work with the child to assist the child in developing or improving specific hand skills such as grasp, in-hand manipulation, or voluntary release. Although the therapist may use the intervention time to focus specifically on improvement of one or more of the child’s hand skills, the skills being developed should be immediately and directly linked to use of these hand skills within the child’s daily life activities. Thus during each session with a child, the therapist places high priority on identification of helpful strategies that can and will be used outside of the therapy session. These strategies can include identifying ways in which adult facilitation of the new skills will occur and ways in which multiple repetitions of the skill can be elicited to support proficiency, speed, and spontaneous skill use. The decision about a focus of hand skill goals on adaptation or motor skill remediation can vary over time and for different skills, depending upon the child’s needs and the degree of the child’s disability. Vygotsky’s (1978) concept of the zone of proximal development can be very useful in considering the most appropriate approach for particular skill areas. This concept focuses upon the amount of adult or peer assistance or guidance needed to complete a skill. It suggests a
Intervention for Children with Hand Skill Problems • 241 focus on the child’s abilities, rather than upon his or her disabilities, as it considers the skills that are “close” (i.e., within the “zone of proximal development”). The “zone of proximal development” falls between those skills that the child is able to do independently and those that the child is unable to do, even with adult or peer guidance or assistance. Clearly, even within the “zone of proximal development,” some skills are nearer to the “independent” end of the continuum, whereas others are nearer to the “unable to complete” end of the continuum. When a child’s skills are not in the independent category and not within the “zone of proximal development,” yet the child needs a particular skill, adaptation or compensation is necessary. For example, if the child is unable to cut foods because of an inability to hold a fork to stabilize food with a utensil in one hand while cutting with a knife held in the other hand, an adaptation is needed. Such an adaptation could include using an adapted fork or knife, using a device to stabilize the food, or having the food cut by another person. In contrast, if the child is able to hold both utensils and can bring both hands near midline but has difficulty sustaining them at midline, intervention that is focused on enhancing the child’s skills may be effective and an adaptation may not be necessary. Those skills that require lesser degrees of adult (or therapist) facilitation or assistance are clearly more likely to be responsive to remediation. At times both an adaptation and intervention for motor skill development may be used.
FACTORS TO CONSIDER IN I NTERVENTION PLANNING The Relationship Between Proximal and Distal Control The developmental principle of proximal to distal development often has been translated into a principle for intervention. However, this principle, like many principles of normal development, does not necessarily relate well to intervention. Current research suggests that the relationship between proximal functioning and distal control is functional; it is not necessarily causal (Case-Smith, Fisher, & Bauer, 1989). Although an infant initially may appear to show greater control proximally than distally, infants are developing both proximal and distal control simultaneously. Distal control, however, does take longer to reach full refinement. In fact, different neurologic tracts control proximal and distal upper extremity functions (Lawrence & Kuypers, 1968a,b), with the corticospinal tracts being responsible for distal functions, including well-controlled forearm movements (Paillard, 1990) but not directly
influencing proximal functions. Therefore intervention for proximal control problems does not necessarily result in improved distal control, unless the distal control problem results solely from difficulty placing and holding the hand in space. Therefore as Pehoski (1992) notes, distal control problems should be treated specifically. This point is supported by a number of single subject research studies conducted by Barnes (1986, 1989a,b). She studied the effectiveness of upper extremity weight bearing on hand function in children with cerebral palsy (CP) and found that although some upper extremity movement components improved, grasp and release did not show significant changes; therefore the proximal improvement did not yield distal changes.
The Relationship Between Stability and Mobility The use of motor skills relies on the interplay of stability and mobility. Effective use of mobility of the arm or the hand is based upon stability within the body or the arm. Stability typically precedes the use of mobility. For example, the child develops the ability to grasp an object before being able to move the object by the fingers. Stability provided via seated positioning and its effect on hand function has been addressed in some studies. Noronha, Bundy, and Groll (1989); Seeger, Caudrey, and O’Mara (1984); and Nwaobi (1987) assessed positioning in children with cerebral palsy. Smith-Zuzovsky and Exner (2004) found that the quality of seated positioning had a significant impact on typically developing, young school-age children’s object manipulation skills. Children who were seated in furniture more closely matched to their body size had significantly higher scores on the In-Hand Manipulation Test than did children who were seated in typical classroom furniture that was too large.
The Relationship Between Sensory and Motor Control Children with various disabilities have been noted to have impairments in tactile functioning in their hands (Beckung, Steffenburg, & Uvebrant, 1997; Bumin & Kayihan, 2001; Curry & Exner, 1988; KrumlindeSundholm & Eliasson, 2002; Yekutiel, Jariwala, & Stretch, 1994). Some children seem to have little awareness that they have five digits on each hand; instead they use all four fingers as a unit. They also seem to have little awareness that they have different areas on the palms of the hand. Skold, Josephsson, and Eliasson’s study (2004) with individuals with hemiplegic cerebral palsy corroborated the presence of sensory problems. Comments from these young people revealed substantial issues with sensory awareness of the more involved arm and hand.
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Pehoski (2005) provides a summary of key literature related to the importance of sensory functioning for skilled hand use (see Chapter 1). Research by Gordon and Duff (1999) illustrates the critical role of tactile functioning on grasping and lifting objects in typical children and adolescents and those with cerebral palsy (see also Chapter 3). They state that “the impairments in grasping in children with hemiplegic CP are largely but not exclusively due to disturbed sensory mechanisms which may have direct implications for therapeutic intervention” (p. 586).
These findings are supported by Krumlinde-Sundholm and Eliasson’s study (2002) in which specific types of sensory problems were related to dexterity difficulties in children with hemiplegic cerebral palsy. Case-Smith (1991) found that children with both tactile discrimination problems and tactile defensiveness had significantly poorer performance on in-hand manipulation tasks than did other children. The individuals in the Skold et al. (2004) study noted the negative effect of their sensory problems on functional use of this arm and hand.
The Child’s Attention and Cognitive Skills The child’s attention and cognitive functioning have a significant influence on goals and intervention strategies for hand function difficulties. The child’s understanding of objects and their ability to be used with other objects to accomplish tasks affects the child’s desire to use the hands to make objects move and interact with one another and the products of that manipulation. Although children acquire some aspects of object knowledge and their actual and potential relationships through manipulating them, the child’s cognitive functioning seems to drive (or at least set the stage for) the acquisition of increasingly complex fine motor skills. Therefore generally the child needs to understand the goal of a hand function activity. If not, the child will not have a context for use of the skills the therapist is attempting to facilitate. For example, the child who cannot attend to two objects simultaneously will not be able to grasp two objects simultaneously and therefore will not bang two objects together. This child is not able to stabilize materials with one hand while manipulating with the other.
Opportunities for Skill Repetition and Practice Motor learning theory emphasizes that skills are acquired using specific strategies and are refined through a great deal of repetition and the transfer of skills to other tasks (Croce & DePaepe, 1989). Exner and Henderson (1995) provide an overview of motor learning relative to hand skills in children. Opportunities for practice of
a new motor skill are extremely important in moving a skill from the level of needing conscious attention in its use to the level of spontaneous and automatic use. For practice of a motor skill to occur, either it should be a skill that the child will automatically repeat independently or planned practice opportunities should be created. Older children with sufficient cognitive skills and motivation may be able to be provided with a list of specific skills to practice. When providing a child with this type of “homework” activity based upon therapy recommendations, the child tends to do best if given written instructions and a method of recording (e.g., a chart) when he or she practiced the skill and for how many times. Teachers or parents or other family members also can support practice opportunities. However, realistic expectations of parents are critical, particularly because parenting a child with a disability has numerous challenges. Cronin’s study (2004) illustrates the stressors on mothers of children with developmental and other health issues. A key theme of many of these mothers is the challenge of managing daily routines. Therefore meaningful opportunities for skill practice are most likely to occur when the therapist works with the family to enhance the child’s occupational performance or create opportunities for practice of motor skills within the context of normal occupational routines.
Importance of Addressing the Child’s Interests As Pehoski (1992) notes, hand skills and interest and motivation are intimately related. A child’s interest in an activity—an activity that has meaning and significance for the child—is critical for the child to be fully engaged in the intervention process. Hand skill intervention cannot be done to a child; it must be done with the child’s involvement in the activities and with the child’s belief that he or she can be successful in accomplishing the activities presented. When a child engages in an activity with little or no attention to the task or no intrinsic investment in the activity, little improvement and carryover into other occupational tasks are likely. Erhardt (1992) also makes the point that in planning intervention for eye-hand coordination, the therapist must take into account the child’s intrinsic desire to play and the child’s cognitive development because these are the impetus for “purposeful, goal-directed, eye-hand coordination behaviors” (p. 23).
To address the issue of the role that motivation and interest may have in therapy sessions, DeGangi et al. (1993) conducted a study that focused on the child’s active selection of activities used in the therapy session versus therapist-selected activities. They compared
Intervention for Children with Hand Skill Problems • 243 child-centered intervention, in which the adult facilitates the child’s activities but the child selects the activities from among those provided in a therapeutic environment, with structured sensorimotor intervention in which the adult directs the child’s activities. The childcentered intervention seemed to result in more change in the children’s fine motor skills, as measured by the Peabody Fine Motor Scales, than the sensorimotor program did, but the difference in gains between the two approaches was not significant. DeGangi et al. (1993) concluded that “in practice, the therapy approaches used in this study may be blended or sequenced one after the other for best results” and that “this study provides preliminary evidence that children with sensorimotor dysfunction benefit from approaches that elicit adaptations to environmental and task demands through the use of play and structured learning techniques as therapeutic mediums” (pp. 782–783).
Case-Smith’s study (2000) of intervention for preschool-age children also showed that play and peer interaction are important factors in the outcome of therapy for fine motor problems. In her study of occupational therapy intervention for 44 children across a school year, she found that in many cases therapists used play and peer interaction activities within therapy sessions that focused on fine motor skills. The study findings support the conclusion that “play activities and peer interaction [within therapy sessions] were predictive of the fine motor/visual motor outcomes” (p. 377).
Case-Smith notes that play activities are important in children’s motivation and focused involvement with activities and contribute to practice of skills in a variety of meaningful situations. The remainder of this chapter addresses structured approaches for hand skill intervention, primarily through or in conjunction with play and other occupational tasks of children. The importance of the environment also is stressed.
GOAL SETTING FOR HAND SKILL INTERVENTION CONSIDERATIONS IN SETTING GOALS The assessment process used by the therapist with the child and family has an impact on the framing of goals and interventions. As stated in the Occupational Therapy Practice Framework (2002)
“‘engagement in occupation’ is viewed as the overarching outcome of the occupational therapy process” (p. 615).
This focus emphasizes occupational performance as the primary goal of intervention. Weinstock-Zlotnick and Hinojosa (2004) describe an approach to intervention that allows a focus on foundational issues (often called a “bottom-up” approach), as well as occupational performance (often called a “top-down” approach). They note “it is the ultimate goal of therapeutic intervention to encompass both poles of the component-function continuum, wherein, both the ‘top’ and ‘bottom’ of an individual’s functional limitations are reached and successfully achieved or at least addressed” (pp. 556–557).
Thus the most effective approach when a child shows potential for motor skill improvement is to keep the child’s occupational performance as the central concern while addressing particular motor skills that support the occupational performance. Generally, progress in particular motor skill areas is important only when the skills are or will be used within the child’s daily activities. For both occupational performance and motor skills, consideration of the typical sequence of skill development approach is important, but the developmental sequence only rarely can be translated into or used as the primary guide for intervention goals. For example, in identifying development of a fingertip grasp or skill in using palm to finger translation as a goal area, the therapist should determine if the child has the developmental readiness for the skill and also relate this motor skill to specific occupational tasks that are developmentally appropriate for the child, such as playing a game with peers or handling money to purchase items independently. Similarly, for example, increasing the child’s ability to do palm to finger translation with more objects has meaning only if the child needs to be able to use a more complex level of hand skills. Determining the appropriateness of establishing a goal for a particular hand skill entails an understanding of the child’s development in a number of areas, as well as his or her environmental demands. The concept of the “zone of proximal development” can be useful in designing an intervention plan with goals that are realistic and achievable. Using this concept, the therapist is interested in determining those skills that are close or within reach, not the skills for which the child is still missing many prerequisites. Skills not within reach may be skills that the child needs. If so, adaptations or compensations may be needed to reach these goals. When attempting to improve fine motor skills, however, the child needs to have the prerequisite
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skills or be able to be facilitated in using a particular fine motor skill before that skill is established as a goal. Setting goals for hand skills intervention involves prioritizing the areas that should be addressed while determining those areas most likely to be responsive to direct intervention and those that may need adaptation. Collaborative goal setting with others is vital to the success of the intervention program. Goal setting with parent(s) and teachers (when appropriate) has been recognized as a central consideration in intervention. The child’s perspective on intervention also is important. Although there is little documentation of the role of the child in selecting intervention goals and methods, Missiuna and Pollock (2000) found that young school-age children were able to identify occupational tasks with which they have difficulty and, based upon this assessment, could choose occupational therapy goals and priorities. Although these goals and priorities may not necessarily converge completely with the parent’s goals and priorities (Missiuna & Pollock, 2000), such collaborative goal setting with children as young as possible is important for the interventionplanning process.
SHORT-TERM GOALS FOR HAND SKILL I NTERVENTION Typical childhood occupational performance problems that are likely to have a hand skills component, and therefore are likely to be reflected in short-term goals, include the following: • Poor handwriting • Difficulty managing materials in the classroom • Limited constructive play skills • Avoidance of play with peers • “Messy” eating • Slow dressing, with avoidance of fasteners • Lack of independence in getting ready for school • Difficulty with hygiene skills The following represent examples of short-term goals or objectives for intervention that are focused on remediation of hand skill difficulties. They may be worded with a focus on the motor skill (more in keeping with a “bottom-up” or medical-model intervention) or with a focus on the task that the child will be able to accomplish (more in keeping with a “top-down” or school or home-based model of intervention). In either case, the therapist addresses the occupational performance goals with specific attention to facilitating improvement in the child’s hand skills. Measurement of goal attainment needs to consider both the child’s specific hand skills and use of these skills within important occupational performance areas. The challenge with adding specific occupational tasks to the motor skill goals is that use of the motor skills can appear narrower than actually desired. The therapist typically focuses on the child’s
ability to generalize new motor skills across a range of occupational tasks. Therefore when possible, meaningful evaluation of the child’s effective use of new motor skills includes a range of activities. Consistency of skill use also needs to be a consideration in assessing intervention effectiveness. The goals listed in Box 12-1 have the motor skill identified first, suggesting an emphasis on the motor skill. For examples of goals that have occupational tasks identified first with motor skills included as related to these tasks, see Exner (2005).
RESEARCH RELATED TO HAND SKILL INTERVENTION A growing body of research evidence is lending support to the value of intervention for hand skill problems in children. Children with mild motor involvement such as developmental coordination disorder or clumsiness have shown improvement in various motor skills (CaseSmith, 2000; Shoemaker et al., 2003), as well as children with various degrees and types of cerebral palsy (Barnes, 1986, 1989a,b; Bumin & Kayihan, 2001; Law et al., 1997). The study by Stiller, Marcoux, and Olson (2003) was less conclusive about test findings of improvement in hand skills, although parents and teachers reported improvement in the children after intervention. Although individual sessions of the therapist and child appear to be the most common form of intervention, studies by Case-Smith (2000) and Bumin and Kayihan (2001) had positive findings associated with small group intervention with children. This type of intervention can support engagement in playful activities, repetition of motor skills, and opportunities for social skill development (Exner, 2005). In addition, small group intervention can be more cost-effective than individual interventions or allow for two or more sessions for the same cost as an individual session.
INTERVENTION STRATEGIES FOR HAND SKILL PROBLEMS In planning an intervention session, the therapist considers the specific hand skill goals while simultaneously considering other goals for the child, the child’s interests and abilities, and the child’s ability to participate in the selection of materials or activities for the session. Each session’s activities must be suited to the particular child; activities that are particularly good for one child may be of little interest to another. The child’s motivation to participate in the activities is an essential factor to consider.
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BOX 12-1
Sample Short-Term Goals for Grasp, Voluntary Release, In-Hand Manipulation, and Bilateral Hand Skills
SAMPLE SHORT-TERM GOALS FOR GRASP The child will: • Use a power grasp on tools such as eating utensils, toothbrush, hammer • Modify use of a radial finger grasp according to pressure requirements for small objects to pick up and hold various finger foods • Supinate the forearm slightly during approach and maintain this during a radial finger grasp to allow for visual monitoring of tasks such as putting items in a cabinet, handling game board pieces, and opening packages • Use a full palmar grasp with wrist extension and varying degrees of elbow flexion/extension while completing dressing tasks SAMPLE SHORT-TERM GOALS FOR VOLUNTARY RELEASE The child will: • Release objects that are stabilized by a supporting surface (e.g., a peg into a pegboard or a spoon into a dishwasher container) • Voluntarily release lightweight objects onto a flat surface (e.g., a class paper into the teacher’s desk tray) • Place an object within 1 inch of other objects without disturbing these by using minimal finger extension (e.g., a glass on a table or a container in a medicine cabinet) • Release objects while maintaining the forearm in midposition to allow for upright object placement SAMPLE SHORT-TERM GOALS FOR IN-HAND MANIPULATION The child will: • Use shift skills in handling fasteners on clothing • Use shift skills in managing paper for cutting with scissors • Use translation and shift skills in handling money • Use simple rotation (or complex rotation) to position a crayon or pencil appropriately in the hand • Use simple rotation to open and close bottles • Use translation skills (with or without stabilization) to finger feed effectively SAMPLE SHORT-TERM GOALS FOR BILATERAL HAND SKILLS The child will: • Carry objects with both hands (e.g., carry a bag of groceries or a tray of food) • Stabilize an object using grasp, while manipulating with the other hand (e.g., grasp a crayon box while putting crayons into it) • Stabilize materials effectively with one hand while manipulating with the other (e.g., stabilize paper effectively with one hand while handwriting) • Manipulate objects with both hands simultaneously (e.g., shifting paper with the nonpreferred hand while using scissors to cut with the other hand)
In addition to a variety of nonmotor elements the therapist considers in planning intervention, the therapist usually attempts to select activities to address a variety of motor factors that contribute to selected hand skills. For example, when the focus is upon the child being able to use a radial digital grasp pattern with varying amounts of pressure, intervention may address radial-ulnar dissociation within the hand, wrist stability, ability to extend the fingers with the wrist in a neutral position, ability to grade finger opening for an object, ability to use a small range of finger flexion (rather than full flexion), or ability to sustain interphalangeal (IP) extension with metacarpal-phalangeal (MP) flexion so as to grasp a flat object. The therapist perhaps should prepare the child to work on these skills by addressing other motor-related issues such as tone, strength, cocontraction, and range of motion. The amount of time for intervention not only influences the number of different skills that may be addressed, but also the number of practice opportunities. Within a session the therapist may focus on a variety of hand skills or only one or two. The eight areas outlined in the following may be addressed when the therapist can work with the child directly for 45 to 60 minutes; the order of the suggested interventions is such that skills can build on one another. Obviously some areas are omitted or addressed only briefly when a shorter session is used or when intervention is being provided in a classroom setting or through consultation. However, the therapist always needs to consider the intervention setting and its features (the environment), attempt to create a supportive physical environment, and develop or provide cognitive and social supports for the child’s performance. In addition, the child’s positioning and ways in which the skills may be integrated into occupational performance must be considered for each intervention session. Box 12-2 lists a typical sequence of areas that may be addressed within an intervention session that focuses on hand skill problems.
BOX 12-2
1. 2. 3. 4. 5. 6. 7. 8. 9.
A Typical Sequence of Areas That May Be Addressed Within an Intervention Session That Focuses on Hand Skill Problems
Positioning of the child and the therapist Tone and postural/proximal control Tactile/sensory awareness/discrimination Isolated arm and hand movements Grasp Voluntary release In-hand manipulation Bilateral hand skills Integration of skills into occupational performance
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In sessions that focus on improving the child’s hand skills in one or more of these areas, the therapist’s role is to: • Address positioning for task engagement • Select materials that allow for ease of handling • Provide sufficient time for task completion • Use (if appropriate) cuing for these hand skills While promoting improved motor control, attention also can be given to addressing tactile or proprioceptive awareness and discrimination, as well as related perceptual and cognitive, play, and social skills.
POSITIONING OF THE C HILD AND THE THERAPIST Positioning should be specifically selected to present the type of postural support or challenge that the therapist believes is most desirable for the hand skills that will be addressed. In a specific session, it may be appropriate to work on a particular skill first with the child in a relatively non-demanding position, then work on the same skill in a somewhat more posturally demanding position. For other children, working with them in the position in which they will be using the hand skill(s) being emphasized is the better option. The most commonly used position for intervention and functional use of fine motor skills is sitting; standing is the next most common body position for use of hand skills. Supine, side lying, and prone may be used for their therapeutic benefits, particularly with children who have limited skills or need to improve proximal stability. For the child with very limited motor skills, the most appropriate position for working on arm-hand skills may be supported supine or supported side lying. In these positions skills such as visually looking at the hand(s), using a palmar grasp pattern, sustaining grasp during arm movements, sustaining grasp with the wrist in neutral extension, reaching followed by gross or palmar grasp, and using crude voluntary release may be addressed. The prone on elbows or forearms position can be useful for assisting children to develop selected hand skills. If the child has some difficulty with stability, emphasis may be placed on the child co-contracting at 90 degrees of elbow flexion, without pulling into more flexion. Being able to sustain a position of 90 degrees elbow flexion is helpful for effective hand use in most tabletop activities; in addition, some standing activities require that the forearm remain on or near the work surface. To stabilize materials the nonpreferred hand needs to exert pressure into elbow extension while maintaining 90 degrees of elbow flexion. In addition, forearm supination and grasp with the wrist in neutral or slight extension may be addressed in this position.
For these hand skills to be carried out in the prone position, activities that require a relatively small range of movement must be used. Children usually can use a wider range of movement in sitting or standing positions. Sitting at a table is often preferred over other positions for hand skill intervention. When a table is used, it should be at or slightly above elbow height. Using a lower table tends to facilitate upper trunk flexion, which promotes humeral internal rotation. Using a higher table places the child’s arms in abduction and internal rotation. Internal rotation leads to use of elbow flexion, pronation, and wrist flexion. A table at elbow height makes it possible for the child to use humeral adduction and slight external rotation, which make supination and wrist extension easier to use. Sitting in a chair without a table (or for some children, sitting on the floor or on another surface) also may be useful, particularly if the goal is to improve skill in moving objects in space while maintaining a goodquality grasp. When a table is not in front of the child, the therapist often has more opportunity to do both proximal and distal handling to facilitate the child’s movements into external rotation, elbow extension, supination, wrist extension, and finger flexion or extension. Standing is an important position to use when working on some hand skills if the child has the postural control to manage standing and hand use. Generally, children find it easier to develop a degree of proficiency when carrying out the skills in sitting, then to begin using these skills in standing. Examples of skills that may benefit from a sitting to standing progression are buttoning, engaging the bottom of zippers, brushing teeth, and handling money. For many of these skills the child initially may find it easier to accomplish the fine motor tasks while standing by leaning against a surface to obtain some stability. Gradually the use of this support surface may be decreased.
TACTILE OR SENSORY AWARENESS OR DISCRIMINATION Because a sensory problem, if present, is a major factor in use of hand skills, attention to tactile or proprioception is a central element—and may be the major focus—of a hand skill intervention program for many children. For children with tactile defensiveness, the therapist should begin intervention with a focus on decreasing tactile defensiveness, because children with tactile defensiveness are aversive to any other intervention activities if they are intolerant to touch from objects or the therapist. Activities involving firm pressure, including weight bearing, pushing large objects with the hands, and squeezing objects, can be useful in
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BOX 12-3
Some Typical Activities Used for Sensory Awareness and Discrimination
1. Rubbing lotion on the fingers one at a time 2. Finding objects in beans, rice, or sand (graded finger movements are used to get the grains of rice or sand off the objects) 3. Pulling pieces of clay off a ball of clay 4. Pushing fingers into therapy putty or clay 5. Stretching rubber bands around the fingers 6. Playing games to identify objects held in the hand
quality of grasp did not improve as a result of the weight-bearing intervention. Thus the components that changed as a result of the weight-bearing intervention were those inherent in the weight bearing itself. These components are important for good-quality hand function and should be emphasized. However, intervention that specifically focuses on supination and hand function is needed also. The focus of the remainder of this chapter is primarily on using structured activities and some degree of handling to address children’s hand skill problems.
ISOLATED ARM AND HAND MOVEMENTS dampening the over-responsiveness to light touch that is common during grasp, release, and manipulation activities. For all children who have a program for hand skill intervention, attention to tactile discrimination can precede and also be incorporated into a variety of activities designed to enhance hand skills. However, when the child has significant tactile discrimination problems, the therapist should make sensory issues a key focus during an intervention session, rather than let tactile input be only another dimension of the motor activity as it can be for children with milder sensory problems. Typical activities used for sensory awareness and discrimination are included in Box 12-3.
TONE AND POSTURAL OR PROXIMAL CONTROL Postural control is a significant consideration in intervention with many children who have hand skill difficulties. Head control, trunk control, prone skills, and sitting skills often are problem areas for these children. If the therapist has specific goals or the child needs intervention to allow for more effective hand placement in space, postural control needs to be addressed next. Boehme (1988), Nichols (2005), and Exner (2005) provide activity suggestions for this area. Barnes’ studies (1986, 1989a,b) have provided some empiric data in support of using upper extremity weight bearing to improve hand function in children with spastic cerebral palsy. In her single-subject studies she found that extended-arm weight bearing increased the children’s use of wrist extension for initiation of grasp and during voluntary release. In her first study (1986), she found that reach with an extended elbow also increased after weight-bearing intervention. In a later study (1989a), she did not find an increase in elbow extension but did find an increase in index finger extension during initiation of grasp. Supination and the
Children often find it easier to work on a new movement component (a) in isolation from other movement components, (b) when not handling objects, or (c) when handling well-stabilized objects as compared with using the movement component within an activity that has objects that are not stabilized. For example, supination and pronation, wrist flexion and extension, and MP flexion and extension with IP extension may be addressed by playing a game with the child in which the child is tapping the table, or his or her leg, or a drum and is only using the desired upper extremity motion. The therapist may assist the child to stabilize a more proximal body part (e.g., the humerus if using supination or pronation, the forearm if using wrist extension or flexion, the dorsum of the hand if using MP flexion or extension). The therapist also may assist the child with actively using internal rotation, pronation, and wrist flexion, because even children who tend to hold their arms in these patterns have functional difficulty using active internal rotation, pronation, and wrist flexion. They need assistance in developing control over the movements, as well as assistance in holding in a more externally rotated or extended or slightly supinated position. Supination is a particularly difficult movement component for children with abnormal tone. Even children with only slightly low tone tend to stabilize in full pronation when engaging in fine motor tasks. Full pronation is functional for palmar grasp patterns, but use of pronation when precision grasp patterns or object manipulation are needed interferes significantly with thumb mobility and distal finger control. Being able to hold various degrees of supination is critical for higher-level hand skills. Full supination is helpful in performing activities, but the most important range of supination for functional skill use is between full pronation and midposition. The ability to hold at any point within this range is important. During most skills that involve controlled use of the radial fingers and thumb, the forearm is in approximately 30 to 45 degrees of supination.
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Intervention to enhance use of supination can include positions and activities in which supination is easiest to use versus those in which it is more difficult to use. Supination is easiest when the humerus is adducted (close to the side of the trunk) and the elbow is flexed. When the humerus is in 90 degrees of flexion and the elbow is fully extended or when the humerus is in full horizontal adduction and the elbow is extended (as in crossing midline), supination is more difficult to elicit. Planning intervention for supination may use concepts from the process that normal babies appear to use in developing supination control. In normal development, babies first use supination when the elbow is in a great deal of flexion. Supination can be observed as babies bring their hands and toys to their mouths when in supine, and in supported-sitting and prone-onforearms positions. In the latter position they also begin to move the forearms from full pronation into varying degrees of supination while weight shifting. Gradually babies use more supination in sitting with the elbows in about 90 degrees of flexion. For example, by about 8 or 9 months of age, the normally developing baby can bang two objects together; this skill illustrates at least two aspects of motor development (and other areas of development as well): the ability to use a finger surface grasp and the ability to hold at least one forearm in midposition so that the surfaces of the two blocks can come together. In another month or so the baby is able to clap the hands together, thus demonstrating the ability to sustain full finger extension with supination to midposition in both hands. Babies also begin to use this range of supination (0 to 90 degrees) to carry out simple activities such as holding a cup, finger feeding, and visually inspecting objects they are holding. The baby now can reach with supination to midposition. When the baby is reaching laterally (using abduction), a greater degree of supination may be observed as compared with forward reaching (using shoulder flexion). Specific suggestions for enhancing supination, in general order from least to most difficult, include the following: 1. Encourage mouthing of toys (if age appropriate) and finger feeding. 2. Facilitate supination with the forearm on a surface, such as in weight bearing on the floor or on a mat or while seated at a table. While the child is sitting, the therapist may find it helpful to place an object in the child’s hand with the child’s forearm pronated, then use his or her hand to stabilize the ulnar border of the child’s forearm so the child has a surface to work against for the rotation (and so that the child can see the object placed in the hand) (Figure 12-1). This strategy also may be helpful if
Figure 12-1 Therapist facilitates the child’s use of supination by providing stability at the ulnar border of the child’s forearm and cues the child to look at the object in the hand.
the child attempts to compensate for difficulty with supination by using wrist hyperextension. 3. Encourage the use of 45 to 90 degrees of supination followed by grasp of an object with the elbow in 90 degrees of flexion, with at least the elbow supported on a surface. The object should be presented in a vertical orientation to facilitate the use of forearm rotation. Some children respond well to the verbal cue “keep your thumb up” because this provides them with visual information about the desired arm or hand position. The child may be encouraged to sustain this position if he or she must transport the object a short distance before placing it into a container or board that requires the forearm to be held in supination. An example of this sequence is reaching and grasping large birthday candles, then putting them into a pretend cake. If the child can accomplish supination to midposition with both hands, banging objects together may be possible. He or she also may be encouraged to hold large blocks or nesting cans by putting one hand on either lateral side of the block or can and stacking these. In this activity the child is being asked to supinate, then initiate grasp and maintain the supination while engaging in a simple activity. 4. Encourage lateral reach followed by grasp. Most children with limited use of supination find it easier to combine humeral abduction with external rotation and supination than to use humeral flexion with external rotation and supination. Perhaps objects initially should be presented laterally to the child’s body to allow the child to use abduction but to move out of internal rotation (and into external rotation), which allows for the use of supination. Objects may be presented low (relative to the child’s body) initially and gradually raised higher
Intervention for Children with Hand Skill Problems • 249 begin at one level, then to move up one or even two levels for a few object presentations within a session. When the child has difficulty maintaining skill at the higher level, the therapist should move back down to a lower-level skill. Most sessions consist of using two or more levels, with the therapist helping the child to develop greater competence at the lower level and to explore a level that is slightly more challenging.
G RASP
Figure 12-2 An object is presented laterally to the child’s body and lower than shoulder height to facilitate the use of external rotation and supination during reaching.
(Figure 12-2). The therapist may find it possible to gradually present objects diagonally to the child’s body (in 60 degrees of horizontal abduction, then 45 degrees, then 30 degrees) to assist the child in moving toward a more anterior reaching pattern. 5. Encourage forward reach using shoulder flexion and some degree of external rotation. The object is positioned in front of the child’s shoulder, not at midline. The object may be placed anywhere between the child’s leg (in sitting) and the shoulder, depending on the child’s ability to control external rotation and supination while completing the reach. With increasing height of the object in front of the child’s body, the child will have a greater tendency to substitute with shoulder elevation, humeral abduction, and internal rotation. Positioning of the object at the optimal height for the child and using slight facilitation at the child’s elbow to help the child initiate and complete the external rotation during the reach may help the child to achieve the supination needed. 6. Encourage reach to midline, following the strategies suggested for reaching in front of the shoulder. 7. Facilitate reach across midline, following the strategies suggested for reaching in front of the shoulder. The therapist who is working with a child on supination, as with any other skill, needs to be sensitive to the child’s zone of proximal development in determining the most appropriate level or levels for use in intervention. The therapist may find it possible to
In clinical practice, intervention for grasp problems generally is interwoven with intervention for voluntary release problems or in-hand manipulation problems. However, to support clarity of intervention descriptions, strategies for each of these skills are addressed separately. In preparation for addressing grasp skills with a child, the therapist should: 1. Assess the child’s current use of a wide variety of grasp patterns, and 2. Determine the problem(s) most interfering with one or more functional grasp patterns. The more specific the analysis of the problems affecting the child’s hand function, the more specific can be the intervention. The therapist needs to determine if an opposed grasp pattern is possible for the child, and if so, the sizes of objects with which it can be used (e.g., larger, medium-size, or small and tiny ones). Some children can functionally use an opposed grasp pattern on larger objects but not on small or tiny ones because of the lesser degree of stability that these objects provide and the necessary index finger control. For some children, use of the intrinsic muscles of the hand is particularly difficult. These children may be able to use the long finger flexors and extensors (e.g., a palmar or hook grasp) but be unable to effectively use the intrinsic muscles of the hand to allow for more variety and function in grasp. Difficulty with intrinsic muscle control may be particularly obvious if a child is unable to hold a ball using a spherical grasp (which requires the combination of long flexor activity with dorsal interossei and lumbrical activity) or to hold a piece of paper with a pattern of MP flexion and IP extension (which requires use of the palmar interossei and lumbricals). In addition, many children lack adequate thumb stability for opposition; instead they substitute with thumb adduction. Some children are unable to activate any thumb abduction or opposition as their thumbs are pulled into adduction by an overactive adductor pollicis. In addition to the outcome of an analysis of the child’s functioning, information from an analysis of the child’s functional needs should be considered in determining the types of grasp patterns to be emphasized in
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intervention. Some children have an adequate grasp with the finger pads but are not able to effectively use a full palmar grasp pattern for many dressing activities. Some children have only a palmar grasp pattern and thumb adduction, so they cannot pick up small or tiny objects in a functional manner. Thus activities such as finger feeding, cup drinking, and fastener use are negatively affected. Grasp use within functional activities, not only grasp on standardized test items, should be assessed as a basis for intervention planning.
General Intervention Principles for Grasp The following general principles are suggested for intervention for grasp problems. If fisting is a problem, voluntary hand opening needs to be developed before setting any other goals for grasp. In children who have limited ability to voluntarily open their hands, the priority is voluntary hand opening and being able to sustain some degree of finger extension with arm movement (if this seems to be within their zone of proximal development). For children whose hands are held in a fisted position and who need maximal assistance in obtaining and even briefly maintaining hand opening, the goal of grasp intervention is a greater degree of voluntary hand opening and, if feasible, initiating and sustaining a palmar grasp pattern with changing arm positions. Upper extremity weight bearing may be used to facilitate finger extension with wrist extension, but in children who have marked fisting, weight bearing with open hands perhaps should be used cautiously. Most of the children with marked fisting do not have sufficient length in their finger flexors to tolerate this position without compromise in the finger positions used. In this type of weight bearing the therapist must control both the thumb, which typically is pulled into adduction, and the fingers, which may pull up into a boutonniere deformity position. Weight bearing on a curved surface may be more effective than on a flat surface, or the therapist may wish to consider use of a weight-bearing splint or other device (Smelt, 1989). Weight-bearing activities that do not ask the child to assume full body weight may be more effective. An example with the child in a sitting position is to assist the child with hand opening, then move the arm into an extended position so that the hand is placed on the floor or to the side or front on a wall surface. This type of position may allow for some degree of weight bearing while minimizing the abnormal positioning of the fingers and thumb that may occur in a full weightbearing position. Rather than focusing specifically on hand opening, encouraging a greater range of arm movements while remaining as relaxed as possible may help the child to open the hands and maintain them open. Tactile or
proprioceptive input to the child’s arms and hands can be used directly with this technique. Emphasis on arm movements often is most easily accomplished with the child supine. In this position the child can be provided with opportunities to see his or her hands and bring both hands together, which are simple activities that these children have had little opportunity to do. As the child brings the hands together, the therapist can encourage the use of supination with elbow flexion. The child may be assisted with touching stuffed animals with fisted hands, an activity that does not require that the hands be open. Activities that encourage the child to dissociate the two sides of the body may be incorporated, such as having the child touch the stuffed animal’s ear with one hand and his or her own ear with the other hand. In this way one elbow is more extended and the other is more flexed. The child may be encouraged to assist with rubbing lotion on one arm with the other hand to facilitate crossing midline and hand contact on the body while the elbow position is changing. During these activities to promote active arm movement, the child’s hand often begins to open or at least becomes less fisted, and the therapist can begin activities to encourage a full palmar grasp pattern and facilitate changing arm positions while maintaining this grasp. If the child’s fingers and thumb remain somewhat flexed, techniques recommended by Boehme (1988) for facilitating hand opening may be used. Once the child has some degree of hand opening in a supine position, it may be possible to change the child to a sitting position and carry out similar activities. The change in body positions often presents the next level of challenge to the child. Partial or full weight bearing may be added to reinforce the hand opening, if tolerated by the child. The stability of the child and of the objects used is critical. The stability of the child, the surface on which the object is presented, and the object itself are primary considerations in planning intervention for grasp. This principle is supported by the findings of Hirschel, Pehoski, and Coryell (1990). In their study babies who were beginning to develop control of a particular grasp pattern were most successful when grasping from a very firm surface and less successful from an unstable surface. As the child improves in his or her ability to grasp from a surface, the therapist can grade the activity by providing less and less stability. Object characteristics and orientation of objects during presentation are important variables. The size, shape, weight, texture, and slipperiness of the objects selected for use in intervention must be given careful consideration. Round objects, such as dowels, tend to be held in a palmar grasp unless the child has good stability in the fingers and thumb and can maintain a
Intervention for Children with Hand Skill Problems • 251 grasp pattern by opposing the thumb to several finger pads. Therefore many children can handle blocks and other objects with straight sides more effectively than they can handle round objects. Children who do not have good internal stability in their hands should not be expected to hold unstable objects (round, squishy, or lightweight ones) with control in any pattern other than a palmar grasp. Grasp of small or tiny objects should not be a priority for all children. An opposed grasp can be introduced to the child with larger objects, particularly if the child has sufficient hand expansion to accommodate the object. An opposed pattern is used to grasp items such as a cup (a cylindrical grasp), a ball (a spherical grasp), a telephone, and a large block. In many of these opposed grasp patterns the thumb is opposed to two, three, or all four fingers. Some children with disabilities can be assisted in developing skilled use of all types of opposed grasp patterns, as well as the power grasp and the lateral pinch. Therefore the pincer grasp need not be considered the highest level or most important grasp. For many children less attention should be paid to the pincer grasp and more attention given to helping them develop a variety of functional grasp patterns. Supination and wrist stability almost always need attention. Problems with supination tend to be evident when the child needs to use grasp patterns that require more precision, such as a three-jaw chuck (see Glossary), a pincer, or a lateral pinch. These problems may be addressed through use of the strategies suggested under Isolated Arm and Hand Movements. Problems with wrist stability must be addressed before or in conjunction with specific interventions for grasp. Wrist stability may be addressed through use of weightbearing techniques and through emphasis on developing a palmar grip (Boehme, 1988). Wrist extension tends to be used more when holding objects in a full palmar grip than in patterns with only the finger surfaces or pads involved. The size of the object to be used for a palmar grip perhaps should be explored with the child; some children use more wrist extension with small-diameter objects, whereas others use more wrist extension with somewhat larger-diameter objects. Emphasizing better-quality grasp without reach is likely to be more successful than combining reach and grasp. Grasp can be addressed in an intervention session without asking the child to first reach, and then grasp. When reaching before grasp, the child must preposition the hand during movement of the arm, which is usually moving against gravity. Generally, children show better wrist, finger, and thumb prepositioning for grasp when the object is presented close to the hand so that arm movement is not needed simultaneously with hand movement.
Children benefit from developing skill in carrying objects while maintaining quality of grasp before using that grasp within an activity. Many children have difficulty transporting an object while sustaining a good-quality grasp pattern. The child can be assisted in developing the ability to maintain a stable grasp pattern, transport the object in space, and release it. After this skill is developed, the child is more prepared to initiate and use the grasp skill within a more challenging activity. Inconsistency in performance is to be expected. As skills are emerging, inconsistency in execution of the skills is common; therefore consistency in performance is to be expected. This clinical observation is supported by empirical data on development of grasp patterns in nondysfunctional infants. Hirschel et al. (1990) found that normal 13- to 14-month-olds were consistent in the pincer grasp pattern they used. However, 7- to 8month-olds and 10- to 11-month-olds tended to use a variety of grasp patterns when attempting to obtain the object.
Developing Radial Finger Grasp Patterns The following strategies are useful for children who can voluntarily grasp and release objects but who: 1. Lack good quality in one or more grasp patterns, or 2. Are not able to use grasp patterns involving distal finger control. These radial finger grasp patterns include a lateral pinch or grasp with one or more fingers contacting the object and thumb opposition. Further preparation of the hand may be needed before using these strategies. Objects selected should be appropriate for the grasp pattern being addressed but also should be presented within the context of an activity that the child finds interesting. In the following sequence the emphasis is first on assisting the child with grasping, although not asking the child to reach. Objects initially are stabilized well when presented, then gradually presented with less external stability, in response to the child’s development of internal stability. Gradually reach and grasp are combined. The therapist should assess the grasp patterns used by the child at each of the levels to determine the best place to begin therapeutic intervention. Not all children should begin at the first level described in the following sequence. In a session the therapist may find it useful to move back and forth between two or three levels. For example, the therapist may give three object presentations at level 2, then, finding that the child’s performance has deteriorated slightly, give two or three presentations at level 1, then give a few at level 2 again. It then may be possible to give a few presentations at level 3 before finishing that aspect of the session with other object presentations at level 2.
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Figure 12-3 To promote use of an opposed grasp pattern, the therapist stabilizes the dorsum of the child’s forearm and presents an object held with her finger pads directly to the child’s fingers.
Level 1: Grasp from therapist’s fingers. The child is in a sitting position (usually in a chair) with the humerus adducted and the forearm stabilized on his or her leg or on the table surface. The child’s hand is in front of the shoulder, not at midline. The therapist holds the object in his or her fingers and places the object just at the child’s fingers (Figure 12-3). The child positions the hand for grasp, then grasps the object and carries it a short distance before voluntary release. The therapist notes the degree and quality of wrist extension and finger and thumb positioning in the grasp. If the child does not use sufficient wrist extension, the therapist may find it helpful to stabilize the dorsum of the child’s forearm and to hold the object just slightly higher for the next object presentation. If the fingers are too flexed, other preparation of the hand to decrease tone may be needed before the next object presentation. If the quality of the pattern appears good, the therapist will probably find it helpful to give several other presentations in this manner to ensure that the child can consistently maintain this quality before moving to the next level. Level 2: Grasp from palm of therapist’s hand. The child’s arm and hand are positioned as in the first level. The therapist positions the object in the palm of his or her hand with the hand sufficiently cupped to stabilize the object. Then he or she places this hand just under the child’s hand. In this way the child is required to position the hand for grasp and grasp the object that is just slightly less stabilized than when it was in the therapist’s fingers. Again the therapist
notes the quality of the pattern used and determines if other handling would be useful, if the child would benefit more from greater repetitions at the preceding level before trying this level again, or if this type of presentation should be used again. Level 3: Grasp from surface, near body with object in front of shoulder, not midline. Now the object is placed on the table surface, which provides it with less stability than does the therapist’s hand. The child’s arm position is similar to that used in the previous two levels. The therapist may find it helpful to place the object on a nonskid surface or stabilize the object slightly with the fingers. The child needs to control the positioning of the hand more in preparation for grasp at this level. Level 4: Grasp from surface, further from body with the object in front of shoulder. At this level the child begins to combine supported reaching with preparation of the hand for grasp. Hand preparation is often better with the object in front of the shoulder because this position allows slight supination to be more easily used. Level 5: Grasp from surface, near midline. The child now begins to work on grasping at midline while controlling the hand, forearm, and elbow position. The child is still not expected to control the humerus against gravity while initiating the grasp pattern. The therapist needs to explore the best distance from the child’s body for the object. Typically a distance that incorporates 120 degrees or more of elbow extension is helpful initially. Then this distance can be varied as the child develops increasing skill. Level 6: Grasp with object off surface. At this level the child needs to control the humerus against gravity, including the degree of external rotation used. At the previously described levels, external rotation and supination could be assisted by the surface. Now the therapist’s positioning of the object can help the child orient the arm into slight external rotation and the forearm into slight supination (as described in the section on supination). Again, distance from the child’s body can be varied, as can positioning of the object in front of the child’s shoulder or at midline. Additional intervention strategies may be needed for the child who is working on grasping and holding flat objects by using MP flexion and IP extension of the fingers and thumb opposition or adduction. Activities that involve finger adduction with extension, such as rolling out clay while keeping all fingers together and straight, finger games that involve finger abduction and adduction, squeezing balls of clay until they are flat by using the thumb pad against the entire pad of the index and middle fingers, shaking dice in the palm of the hand by cupping the hand (curving the transverse metacarpal arch and the carpal arch), and games or
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Figure 12-4 Use of a thick, flat object may assist the child in developing grasp with metacarpal-phalangeal flexion and interphalangeal extension.
Figure 12-5 Young child demonstrates use of a palmar grasp on a “tool.”
activities that involve holding thick flat objects may be helpful (Figure 12-4). Verbal cues about the desired pattern also may be useful in helping the child to perform the desired pattern.
Developing a Power Grasp Pattern The preceding strategies may be less helpful in facilitating a power grasp than they are in facilitating opposed grasp patterns. Children with poor stability in their hands tend to use a palmar grasp on tools (e.g., knives, toothbrushes, hairbrushes, hammers) rather than a power grasp in which the ulnar fingers provide stability for the handle and the radial fingers are more extended so that they can reorient the tool as necessary (Figures 12-5 and 12-6). Not all children with motor disabilities are able to develop a power grasp, just as not all children develop a pincer grasp. However, for those children who have the potential to use a power grasp, development of this skill enhances their ability to be more effective and efficient with many daily life tasks. Usually children who have some degree of instability in their hands but have reasonable thumb opposition and finger control in grasping stable objects can develop a power grasp. Facilitating the child’s use of radial-ulnar dissociation within the hand can be helpful in preparing him or her for use of a power grasp. A useful strategy in this skill development is to assist the child with retaining one or more objects in the middle to ulnar side of the palm with flexed ulnar fingers while having the child use the radial finger(s) and thumb to grasp and release objects. Initially the object held in the ulnar side of the hand might be medium sized so that the degree of
Figure 12-6 An older child demonstrates use of a power grasp on a “tool.”
finger flexion necessary (and the degree of differentiation in radial-ulnar finger positions) is less; gradually the size of this object may be reduced. Similarly, the size of the objects grasped with the radial fingers and thumb may be decreased as the child’s proficiency increases. The therapist also may consider carefully selecting or modifying the diameter and shape of objects to be held with a power grasp. Tools with thin or rounded handles are more difficult for the child to grasp well; children with instability may grasp handles that are slightly larger in diameter or have ridges or indentations more effectively. Also the degree of power needed within the activity should be graded because increased demands for power tend to cause the child to move from a more refined power grasp pattern to a palmar grasp pattern. After grasping an object, the child may use the object to complete a task (e.g., use a hammer to pound a nail), use in-hand manipulation to adjust the object after grasp (e.g., turn a key to fit it into a lock), or
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voluntarily release the object (e.g., put coins into a machine to buy a candy bar).
VOLUNTARY RELEASE Motor control problems with voluntary release typically result from three key areas of difficulty: (a) poor arm stability; (b) increased flexor tone, which causes fisting or difficulty with grasp using the finger surface; and (c) lack of effective use of the intrinsics. In the latter case, problems are seen in poor IP joint extension or poor MP joint control. A typical pattern seen in poorquality voluntary release is MP joint extension with or without IP joint extension. Problems with stability and lack of extensor activity appropriately balanced with flexor activity interfere with the effectiveness and efficiency of voluntary release. Some children with these problems resort to using tenodesis action by flexing at the wrist to initiate the voluntary release (and may use the same pattern to initiate grasp). Arm instability is often a key contributor to voluntary release problems in children with involuntary movement or tremors. However, instability also may negatively affect voluntary release in children with low or high tone who do not have excess movement. For effective voluntary release the child needs to release where and when he or she wants to do so. The arm is important in transporting the hand to the location for release. Holding the arm in a stable position during hand opening contributes to accurate timing of the release. Several strategies may be used with children who have stability problems that affect voluntary release. Upper extremity weight bearing, particularly on extended arms, may help the child to develop improved cocontraction at the scapulohumeral area, elbow, and wrist. Reaching activities that involve touching a desired target and holding that position for a few seconds also may be helpful, particularly if the reaching is done in a variety of planes of movement. For the child who has marked instability or needs to function despite some instability, teaching the child to stabilize the arm against the body or on a surface before opening the hand may be a helpful compensatory strategy. Many of the stability problems that affect voluntary release are related to problems with wrist stability during finger extension; stabilizing in wrist extension allows finger extension without using tenodesis action and supports accuracy of release. Some children show wrist flexion during elbow flexion, but they are able to voluntarily release with the wrist in extension if the elbow is extended. For these children, and even those who have significant flexor tone at the wrist and fingers when the elbow is flexed, an effective strategy can be to facilitate releasing objects away from midline and with the elbow extended. As with the strategy discussed for
Figure 12-7 Allowing for elbow extension by placing a container on or near the floor may encourage use of wrist and finger extension for voluntary release.
facilitating supination, humeral abduction and external rotation may make it easier for the child to use elbow extension and slight supination, which may in turn allow voluntary release with wrist extension to occur. Releasing into a container placed on the floor, or at least lower than the seat of the child’s chair, also may allow the child with high tone or little voluntary control to learn to take advantage of gravity or at least relax the finger flexors (Figure 12-7). Gradually the container used for release can be brought onto a table surface (if initially down low), closer to the child’s body (if initially further away from the body), and closer to midline (if release initially in front of the shoulder or lateral to the child’s body). However, these strategies are unlikely to be beneficial for the child who can release with adequate control at the shoulder, elbow, and wrist but has difficulty grading finger extension. In addressing problems of voluntary release caused by poorly graded finger extension, the therapist should consider the quality of the child’s grasp. Voluntary release quality can be no better than the quality of the grasp. However, the quality of voluntary release can be poorer than the quality of grasp. Therefore when the child holds an object in a palmar grasp, voluntary release is initiated with full extension (or almost full extension) of the fingers. If, on the other hand, the child holds an object with the finger pads, he or she may release with just slight finger extension or excessive finger extension may be seen. Because voluntary release quality depends so much on grasp quality, the two skills often can be worked on
Intervention for Children with Hand Skill Problems • 255 effectively within the same activity. Certainly the therapist must address the quality of the child’s grasp in intervention for voluntary release problems. For some children the focus is on decreasing wrist and finger flexor tone to allow for grasp on the finger surface rather than in the palm. For other children the emphasis is on enhancing the use of intrinsic muscle activity to allow for more control in grading both grasp and release patterns. For children who have mild problems, attention to forearm stabilization in a slight degree of supination during voluntary release may help them place objects with more accuracy and without bumping other objects with their hands. As children develop more control with voluntary release, the therapist can gradually decrease object weight, stability, or size, and the size of the area used for object placement. A study by Gordon et al. (2003) suggests the value of such strategies. They investigated voluntary release skills in children without disabilities and children with hemiplegic cerebral palsy. The children released objects onto both stable and unstable surfaces at two different speeds. Although the children with cerebral palsy showed difficulties with coordinating the force needed during release, they did demonstrate the ability to both improve speed and accuracy with cuing and under a condition in which greater accuracy was needed. Because the children also showed subtle difficulties in voluntary release with the hand that was believed to be noninvolved, Gordon et al. suggest that “practicing release tasks with the non-involved hand first or practicing bimanual tasks may enhance performance” (p. 247).
They suggest that the therapist could vary the task demands to address accuracy and speed separately and then introduce activities to combine varying degrees of accuracy at different speeds. Eliasson and Gordon’s study (2000) provides some evidence for children with hemiplegic cerebral palsy being able to improve their grading of the grip forces necessary to allow for a more accurate release. In keeping with these suggestions, children with mild motor control difficulties may benefit by using a variety of sizes of objects, including small ones, and objects that are less solid (paper balls rather than solid rubber balls, cotton balls rather than paper balls). Inexpensive toys, which tend to be lighter in weight than sturdy high-quality toys, can be particularly useful. Games in which the accuracy of placement is important and obvious to the child can be selected or developed. For example, some children’s game boards have large areas for the game pieces, whereas others have small areas. Activities that involve the child holding tweezers to grasp and release objects may help the child focus on graded pressure and graded release with a steady arm
position. Also, the therapist can address precise grasp with the child when using the tweezers and other small materials.
I N-HAND MANIPULATION In-hand manipulation skills seem to be the most complex of all fine motor skills. In-hand manipulation involves the adjustment of objects by movements of the fingers so that the objects are more appropriately placed within the hand for the task to be accomplished (Exner, 1990a, 1992). In-hand manipulation occurs within one hand. Five basic types of in-hand manipulation skills have been described (Box 12-4) (Exner, 1992). Each of the in-hand manipulation skills may occur with no other object in the hand at the time of the manipulation or while the ulnar fingers are holding one or more objects in the center or ulnar side of the palm (Exner, 1990a, 1992). When other objects are held in the hand during manipulation, the skill has the term added “with stabilization.” Although almost any child with a disability that affects motor or sensory functioning has difficulty with inhand manipulation skills, not all of these children are candidates for intervention for in-hand manipulation problems. To be considered for intervention specifically for in-hand manipulation problems, the child needs to have: • Index finger isolation • Good skills in basic grasp and release patterns including the ability to grasp a variety of objects and to accommodate the hands to these objects effectively. The child needs to be able to grasp objects at least on the finger surface, not only use a palmar grasp.
BOX 12-4
Five Basic Types of In-Hand Manipulation Skills
1. Finger-to-palm translation: Movement of an object from the fingers to the palm 2. Palm-to-finger translation: Movement of an object from the palm to the finger pads 3. Shift: Slight adjustment of the object on or by the finger pads 4. Simple rotation: Turning or rolling the object 90 degrees or less, with the fingers acting as a unit 5. Complex rotation: Turning an object over (turning it 90 to 360 degrees) using isolated finger and thumb movements From Exner CE (1992). In-hand manipulation skills. In J Case-Smith, C Pehoski, editors: Development of hand skills in the child (pp. 35–45). Rockville, MD, The American Occupational Therapy Association.
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Other skills that are useful include: Supination to at least midposition Thumb opposition Finger pad grasp patterns Radial-ulnar dissociation; this skill is important for use of in-hand manipulation with stabilization of other objects within the child’s hand. In general, in-hand manipulation activities are realistic only for children who have mild motor disabilities; most children with moderate disabilities lack the ability to use adequate grasp patterns and lack the associated intrinsic muscle control to make in-hand manipulation skills possible. • • • •
General Principles for Developing In-Hand Manipulation Skills The following are strategies that the therapist can use in planning and implementing intervention for children who have difficulty with in-hand manipulation. Facilitate the use of the intrinsic muscles in grasp and other hand functions. Many sensory activities (e.g., pulling clay) can be done in a manner that facilitates use of the intrinsic muscles. Intrinsic muscle activity is needed for in-hand manipulation and the grasp pattern that is often used upon completion of object manipulation. This grasp pattern reflects the child’s degree of stability with the intrinsics; in-hand manipulation relies on both mobility and stability of joints controlled by the intrinsics. Emphasis on development and use of a spherical grasp, a pattern that uses a combination of long flexor activity and intrinsic activity and requires cupping of the palm, also may be useful. Encourage use of bilateral manipulation and skills that substitute for in-hand manipulation. Infants manipulate objects between the two hands (Ruff, 1984), and young children often use both hands to turn objects over as well. They also spontaneously use any supporting surface available to stabilize materials during manipulation attempts. For example, young children may use a table surface on which to turn a puzzle piece, rather than picking up the puzzle piece and turning it within the hand. Use of a supporting surface during attempts at object manipulation allows these skills to begin to emerge. However, as typical children become more proficient with their skills, bilateral manipulation and use of a supporting surface are used less often and in-hand manipulation is used more frequently. Thus substitution patterns can be effective for handling many objects, but they are not efficient, particularly when handling small or tiny objects or when both hands should be manipulating simultaneously (e.g., in shoe tying). Children who have the potential to use in-hand manipulation can use bilateral manipulation or surface support as a transitional stage, whereas children who may not be able to develop
in-hand manipulation skills may use these alternative strategies to successfully accomplish tasks. Use small objects first with a new skill. Objects that are small in relation to the child’s hand size are typically easier for them to manipulate than are tiny or mediumsize objects. For example, children find nickels easier to manipulate than dimes or silver dollars. Pegs that are larger in diameter or length are more difficult to handle than are pegs that are 1 to 11⁄2 inches long and 1⁄2 inch in diameter. Tiny pegs are difficult to manipulate. In addition, whereas 1-inch beads are easy to grasp, they are more difficult for the child to manipulate than are 1 ⁄2-inch beads. Therefore when introducing a new skill, the therapist often finds it helpful to carefully select small objects, so that the child can have sufficient finger contact on the object during manipulation but does not need to use all fingers to stabilize the object during manipulation. As the child develops greater proficiency in using a particular skill, the therapist can begin to vary the size of the objects used by including larger and smaller objects. Use cues to facilitate the child’s use of in-hand manipulation skills. Exner (1990b) studied the effectiveness of cues in increasing 3- and 4-year-old children’s inhand manipulation skills. She found that, as a group, the children improved significantly when given either verbal cues to move the objects with the fingers or demonstrations of the in-hand manipulation skills. Although the children showed more improvement with verbal cues for some skills and more improvement in other skills with demonstrations, the use of palm-tofinger translation with stabilization and rotation with stabilization improved with both types of cues. However, not all children showed improved performance with cues. As with other aspects of children’s hand skills, the children’s zone of proximal development for in-hand manipulation should be considered in setting goals. In addition, the therapist needs to determine the best mode for cuing for each child. During testing in this study (Exner, 1990b) some children who were provided with demonstrations (but not verbal cues) seemed unsure of the aspect of the skill that they should imitate. Therefore demonstration cues alone may not be as helpful to the child as demonstration cues with verbal cues. Other children may need only verbal cues to remind them to try the skill with one hand. Consider the sequence of skill difficulty. A general sequence of in-hand manipulation skills has been developed (Exner, 2005) based on research by Exner (1990a); Pehoski, Henderson, and Tickle-Degnen (1997a,b); Humphrey, Jewell, and Rosenberger (1995); and Yim, Cho, and Lee (2003). Children use finger-to-palm translation earlier than other in-hand manipulation skills. Palm-to-finger translation and simple rotation are somewhat more difficult. Complex rotation is next in
Intervention for Children with Hand Skill Problems • 257 terms of difficulty. Of the in-hand manipulation skills without stabilization, shift is the most difficult, probably because of its reliance on good-quality MP flexion and adduction with IP extension. Generally, children develop the ability to use an in-hand manipulation skill with stabilization of other objects in the hand simultaneously soon after they develop the ability to use the same skill without stabilization. A list of suggested intervention activities for each of the skill areas is provided by Exner (2005). Consequently in determining the type of in-hand manipulation skills that will be the focus of intervention for a child who has no skills in this area, the therapist will probably find finger-to-palm translation the easiest to help the child develop. Verbal cuing to the child to “hide the object in your hand” may be helpful in working on this skill. Pieces of dry cereal or coins are good objects for the child to hide. If the child is able to use finger-to-palm translation with a variety of objects, the therapist may begin to work on palm-to-finger translation and simple rotation. For palm-to-finger translation the intervention strategy that tends to be most effective is a backward shaping approach. This is done by the therapist initially placing the object on the volar surface of the child’s fingers at approximately the distal IP (DIP) joint crease and (if possible) asking the child to bring the object out to the pads or tips of the fingers (Figure 12-8, A). For example, a game piece may be placed on the child’s finger surface, and the child asked to place the game piece on a particular color square on the board. If verbal cuing
A
B
is unlikely to be understood by the child, the therapist needs to rely more heavily on the structuring of the activity, for example, using a bank with a narrow slot or a small container or a small surface that requires the child to use a precision grasp (e.g., a pincer grasp) to be successful with placement. After the child is able to move objects well from the DIP creases on the fingers, the object may be moved closer to the proximal IP (PIP) crease but still kept on the index or index and middle fingers (Figure 12-8, B). Eventually it can be placed on the MP crease between the index and middle fingers. Finally, objects may be placed in the center of the palm (Figure 12-8, C). Some children are able to work on bringing objects from the ulnar side of the hand to the radial fingers and thumb, a skill that is helpful for efficient hand use, particularly in the preferred hand. Common objects used when working on palm-to-finger translation are small pieces of food or dry cereal, small cookies, coins, game pieces, small puzzle pieces, beads for stringing, paper clips, caps for markers and pens, pegs, and small blocks. Simple rotation skills often can be addressed early in an in-hand manipulation skill intervention program. Simple rotation tends to be “simple” because the fingers move as a unit to partially turn the object. These skills may be encouraged by placing an object on the distal surface of the child’s fingers (the forearm is pronated) and asking the child to make the object move into an upright position. Slight stabilization of the child’s forearm may help prevent the child’s use of forearm rotation as a substitution for manipulation by the fingers.
C
Figure 12-8 A. Use of palm-to-finger translation may be encouraged by grading the activity. Initially the object is placed on the distal surface of the child’s radial fingers. B. Gradually the object is placed more proximally on the child’s finger surface. C. After success with more proximal placement, the child may be able to use palm-to-finger translation when the therapist places the object in the palm of the child’s hand.
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Although some supination is to be expected when executing a simple rotation skill, the focus is upon eliciting individual finger movements to produce the movement. Activities that may be useful for encouraging simple rotation skills include unscrewing a bottle top, picking up a pen, pencil, or marker that has been placed horizontally on the surface with the writing end oriented toward the ulnar side of the child’s preferred hand, picking up pegs (or a similar object) from a surface and putting them into a pegboard, and rolling clay between the thumb and radial fingers. Again, the therapist may find that demonstrations and visual cues are helpful in increasing the child’s understanding of what to do with the materials. Physically assisting children is easier with simple rotation skills than with translation skills. The therapist may assist the child with rotation by placing his or her fingers over the child’s fingers to facilitate the necessary finger movements. For complex rotation skills the therapist relies on selection of materials that readily facilitate the use of complex rotation supplemented by cues to the child. Children should have the attention skills necessary to focus well on verbal and demonstration cues for complex rotation skills. The ability to respond to cues is important because it is difficult for the therapist to physically assist the child with these skills. Games and imaginative play activities can be used for working on these skills, thus allowing for attention to other goals as well, particularly those that address cognitive concepts and visual perception. Materials that work well for enhancing complex rotation include pegs that can be placed upside down for the child to turn over, cubes that have pictures on one or more sides and can be turned to find the appropriate picture for a category of pictures or a puzzle, a pencil with an eraser that can be turned over to allow for its use and turned back for writing again, markers with caps so the cap can be placed in the child’s hand upside down before the child places it on the marker, and toy people or figures that can be inverted on a surface or in the child’s hand and that should be rotated before placement (Figure 12-9). When children are first working on complex rotation, they tend to need a surface for support, both for their arms and the objects. Therefore it is easier for the child if the therapist places the object on a table surface. Soon, however, it is usually possible to place the object in the child’s hand and encourage the child to at least start the rotation before using a surface for support. Later the child can be asked to use the skill without depending on a supporting surface at all and completely finish the rotation before putting the object down. Once the child can do one complex rotation with an object, the child may be encouraged to attempt repetitive rotations by turning the object over two
A
B
C Figure 12-9 A. The child is forming a picture with a set of puzzle books. He is encouraged to find the side of the block that fits the design being constructed. The therapist has placed the correct side of the block against the palm of his hand so that he must use complex rotation to find it. B. Before using the in-hand manipulation skill of complex rotation, the child must use palm-to-finger translation to move the block toward the distal finger surface. In that process the block begins to be turned. C. Having identified the correct side, the child shifts the object out of the pads of the fingers before placement with the other blocks. (From Case-Smith, J [2005]. Occupational Therapy for Children, 5th ed. St Louis, Mosby.)
Intervention for Children with Hand Skill Problems • 259 times, then three times, and so on. Repetitive rotations help to develop sustained stability with sustained mobility (endurance), which is difficult for many children with low tone. Shift skills generally require the child to have more sustained control of the fingers in IP extension; therefore shift skills are difficult for children who are unable to sustain this pattern. Some patterns of shift tend to be easier than others. One shift movement (e.g., moving a coin from the finger pads to the fingertips for placement) is easier than repetitive shift movements (e.g., moving fingers around paper to allow for cutting with scissors). In an intervention session children may be encouraged to use single shift movements, then gradually increase the number of shift movements used. For example, the child who is holding the fingers on a marker approximately 11⁄2 inches from the writing end may be asked to stretch the fingers down toward the tip and then move the thumb so that he or she is holding the marker more effectively for writing or coloring. When the child can use a single shift movement, the therapist can facilitate the use of shift skills to adjust paper during cutting. The therapist should ensure that the child can hold the paper with the thumb on top of the paper and the fingers in a relatively extended position on the underneath surface before expecting use of shift. Index cards may be easier to use than paper, because the cards are slightly thicker and sturdier than paper (but are still easy to cut). They also are a good size for shifting and cutting. As the child’s skill in shifting the index card improves, larger and larger sizes of index cards may be used. Eventually regular paper may be used. Fully develop each skill before asking the child to combine skills within an activity. Children seem to find that using palm-to-finger translation immediately before using either simple or complex rotation (e.g., moving a key from the palm to the fingers, then turning it for placement) is much more difficult than using simple or complex rotation alone. Therefore children should be assisted with developing palm-to-finger translation that does not involve rotation of the object for placement and simple and complex rotation without palm-tofinger translation before asking for the combination of these skills. When both skills are reasonably well developed, they may be combined for sequential use. Fully develop a skill before asking the child to use that skill with stabilization. Stabilizing other materials in the hand while manipulating an object is quite difficult because it relies on good radial-ulnar dissociation of movements and the ability to do the in-hand manipulation skill with only the radial fingers (Figure 12-10). Therefore the therapist should ensure that the child can use the skill easily before asking the child to hold even one object in the hand while manipulating.
Figure 12-10 Child shows use of simple rotation with stabilization by holding two objects in the hand. One object is stabilized by the ulnar fingers, while the other object is rotated slightly before stringing.
The easiest in-hand manipulation skill to use with stabilization is finger-to-palm translation, because this is only slightly more difficult than using this pattern without stabilization. It requires the child to keep the ulnar fingers flexed while grasping with the radial fingers, and storing another object in the hand only requires movement into finger flexion (which is easier than moving into finger extension). This also seems to be a skill that many young children develop spontaneously as they try to hold several pieces of cereal, candy, or small crackers in their hands at one time. After mastering finger-to-palm translation with stabilization, most children seem to find it easier to work on palm-to-finger translation with stabilization than simple rotation with stabilization. However, the therapist should explore these with the child, and then select the easier skill to work on next. The size of the object being held in the hand can be a factor in making the skill seem easier or more difficult. If it is too small, a great deal of ulnar flexion is needed, thus increasing the requirement for radial-ulnar dissociation. If the object is too large, the child may need to use the middle finger to assist in the stabilization, but then will not have this finger available for manipulation. Children find it easier to hold one other object in the hand than two or more. Initially they also find it easier if the objects to be held are placed in the ulnar side of the hand by the therapist. Later they may be asked to pick up and move an object into the hand and hold it there while manipulating another object with the radial fingers.
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Children with mild disabilities may find it possible to learn to use shift with stabilization and complex rotation with stabilization, but many children find these skills too difficult. If these skills seem possible, the therapist may find that one skill is easier than the other for the child to develop. Shift with stabilization is difficult because of the need to combine a flexion pattern in the ulnar side of the hand with a more extended pattern in the radial side. Thus holding a slightly larger object in the ulnar side of the hand may be somewhat easier when facilitating shift with the radial fingers and thumb. The size of the object being manipulated also is particularly important for complex rotation, because complex rotation generally is carried out by the index, middle, and ring fingers. When stabilization of other objects is necessary, the ring usually is not available to assist in the rotation. Therefore smaller objects are easier to use for complex rotation with stabilization than are larger ones.
BILATERAL HAND SKILLS As with other areas of hand skill development, an understanding of normal development is helpful in selecting goals and planning intervention for children who have difficulties with bilateral hand skills. However, as in all areas of hand skill intervention planning, the therapist should be guided by judgment about the most important functional skills for the child now and in the future. Babies with normal development initially use gross symmetric bilateral skills, such as holding objects with two hands, clapping, and banging objects together. Then they begin to stabilize objects with one hand while the other is manipulating either by holding without grasp (e.g., holding paper while coloring) or with grasp (e.g., holding a container during object placement). Later they develop the ability to manipulate objects with both hands simultaneously (e.g., stringing beads, tying a knot). All children with motor control problems have difficulty with bilateral hand skills. Bilateral simultaneous manipulation is a common problem; children with motor disabilities generally cannot use effective in-hand manipulation with one hand at a time, and certainly not with two hands at one time. Many children with motor control problems, even subtle problems, also have difficulty stabilizing an object with one hand while manipulating with the other hand. Problems may be seen in stabilizing while grasping an object or stabilizing without grasp. Children with marked asymmetry in their arm-hand control also find gross symmetric skills to be difficult, whereas children with milder problems typically can use the more basic skills in this category.
In bilateral hand skills, the issue of spontaneous use is particularly significant. Fedrizzi et al. (2003) found that children with cerebral palsy had substantial difficulties with spontaneous object handling in bilateral tasks. They also tended to show little improvement in these skills between the ages of approximately 2 years and approximately 12 years.
Children with Moderate-to-Severe Motor Involvement The child who has significant asymmetry or significant involvement bilaterally has difficulty with all three categories of bilateral skills. Even most gross symmetric skills require that the child be able to spontaneously open both hands, sustain both hands open or in a grasp position, and use supination to midposition. Although gross bilateral skills may be used as part of an intervention program to help prepare the child for other activities, goals in the gross bilateral skill area may not be the most appropriate. When the child has cognitive skills that make independent performance of functional tasks important, bilateral skills in stabilizing with and without grasp become a much greater priority. Initially the therapist may address either stabilizing objects with or without grasp. Consideration needs to be given to the type of stabilizing that seems to be within the child’s zone of proximal development and the most frequent needs of the child. For example, when stabilizing with grasp, the ability to hold the forearm of the stabilizing hand in supination to midposition is important. Wrist extension to neutral is helpful in stabilizing without grasp. Stabilizing materials without grasp but with an open hand may not be feasible for many children; however, they may achieve sufficient dissociation between the two sides of the body to be able to hold materials with a fisted hand. An important component for this skill is maintaining elbow flexion at approximately 90 degrees so that stabilization with the hand on a surface is possible. In stabilizing materials without grasp, some children can initiate finger extension, but finger flexion increases during the activity. In this case wrist flexion becomes a greater problem than finger flexion and interferes more with effectiveness of object stabilization. Therefore often in initial intervention for the skill of stabilizing without grasp, emphasis is on holding the wrist in neutral extension rather than on finger extension. Activities in prone on forearms weight bearing and in less stressful tabletop activities that involve stabilizing materials are often introduced early in intervention. At times the therapist may ask the child to stabilize materials while the therapist does the manipulation. For example, the child may hold his or her hand on the paper while the therapist draws a picture and asks the child to guess what is being drawn.
Intervention for Children with Hand Skill Problems • 261 Gradually the child is asked to stabilize materials on the surface while doing more with the manipulating hand. Children with marked asymmetry usually need as much attention to the less involved hand as to the more involved hand. Even though the arm-hand with the greater degree of disability seems more in need of intervention, the hand with a mild disability needs to be addressed specifically. The child with significant asymmetry needs a skilled hand to accomplish tasks unilaterally that other children may do bilaterally. The less involved arm and hand have a greater degree of potential for meaningful improvement in skill that will enhance independent functioning than does the more involved arm and hand. Thus intervention needs to focus on both hands. Bilateral simultaneous manipulation is rarely a goal for children with moderate-to severe motor involvement. Therefore for these children the focus needs to be on developing or improving in-hand manipulation in the hand with less involvement and adaptations or compensatory strategies for dealing with other skills if independence in these areas seems possible. The child’s cognitive and perceptual skills influence decisions about the motor skills that seem reasonable for the child. As Skold, Josephsson, and Eliasson (2004) found in their study of adolescents and young adults with cerebral palsy, access to a variety of strategies for completion of functional activities is of great importance. These individuals reported that although certain strategies work under some circumstances, alternatives are needed to meet different environmental demands.
Children with Mild Motor Involvement Children with low tone and those with milder degrees of asymmetry may be able to work on gross symmetric skills and become functional with them. Therefore setting goals in the area of gross symmetric bilateral skills may be reasonable. Intervention for these problems typically uses a graded approach for decreasing the size of the objects used (e.g., the size of the ball to be caught) or increasing precision or timing in the activity (e.g., holding a stick with both hands to hit a stationary target, then a slowly moving ball, then a quickly moving ball) or increasing speed of performance. Although children with mild involvement typically need some intervention for gross symmetric bilateral skills, they need more attention to skills involving stabilizing with one hand while manipulating with the other. Many times these children do not spontaneously stabilize materials with one hand, yet with encouragement or prompting they do so. Intervention depends on the therapist’s assessment of the child’s reason(s) for not spontaneously or consistently stabilizing materials. Such reasons may include poor sensory awareness of one upper extremity, poor ability to dissociate the two
sides of the body so that the hands can assume different functions, and the need to adduct or hyperextend one upper extremity to assist with maintaining good postural control. In addition, as Skold et al. (2004) found in their study, many adolescents and young adults with hemiplegia do not use the more involved hand in bilateral activities as they may wish to conceal the movements of this hand. Intervention typically is directed, at least in part, on the identified factors and the ability of the individual to learn alternative strategies. In intervention designed to facilitate spontaneous stabilization of materials, the therapist may try (and suggest to others) activities that definitely require the use of one hand for stabilization. A highchair tray or a slightly wobbly table may be useful, because materials tend to be less stable on these surfaces than on others. Inexpensive toys that are less sturdy than more expensive ones may be helpful in encouraging the child to use one hand to hold materials down. Simple toys that can be put together without requiring manipulation of objects in both hands can be appropriate, such as a padlock that a key can be put into, markers with caps to put on, and a box with a lid and objects to put inside the box. Children who have good sitting balance may be asked to sit in a chair (but not at a table) and hold a cup or other small container with one hand while putting objects in with the other hand. This type of activity may be done while standing if the child has good standing balance. Children with mild or minimal motor involvement may be able to work toward accomplishing bilateral simultaneous manipulative tasks, such as buttoning with both hands, tying a bow, and doing craft projects. To do so, they need refined grasp patterns and the ability to sustain these patterns, in-hand manipulation skills with at least one hand and preferably both, and skill in dissociating the movements on each side of the body. For these children a graded progression of activities that require stabilizing materials with a refined grasp while using manipulation with the other hand, and activities that require changing the hand that is doing in-hand manipulation, may be useful. In these activities children are usually more successful with more stable materials such as blocks that fit together and other building construction sets before having success with unstable materials such as fabric with buttons and shoelaces. Once the child is ready to try bilateral manipulation with unstable materials, grading also may be used. Large, then medium, then small buttons may be tried; most children find it easier to button when the buttons are low (in their visual field) and on their own body or on another person’s body so the fabric is well stabilized. Initially the fabric should overlap in the correct direction for the child (right over left for girls, left over right for boys) regardless of the placement of
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the item of clothing. Later this may be varied as well. For lacing and tying, thicker (but not inflexible) shoelaces that are just the right length need to be used at first; then the thickness of the laces and their length can gradually be decreased. A study by Hung, Charles, and Gordon (2004) yielded findings that are applicable to intervention for these types of bilateral hand skills. They found that children with hemiplegic cerebral palsy were able to complete a task that involved the two hands completing different activities and were able to alternate hands for the two components of the activity. In this task neither hand was necessary to execute fine control, and the task was completed at two different speeds. Under the condition in which greater speed was necessary, the children showed enhanced coordination. Thus therapists may wish to consider incorporating different degrees of speed into activities, exploring the conditions that may yield greater success for the child.
I NTEGRATION OF SKILLS INTO OCCUPATIONAL PERFORMANCE The child’s ability to generalize the skills emphasized in intervention to other times of the day and other settings is a crucial consideration in planning and implementing intervention. At least some amount of each session needs to be spent engaging the child in activities that will be done in other situations. Unique ways of modifying materials and object presentations may work well in intervention with the therapist, but parents and teachers often have difficulty presenting materials in the same way as the therapist. Thus typical ways of presenting materials also should be used, as well as materials that the child has in the home or school setting. If these strategies are not used, the child will be asked to generalize a new skill to a new setting with new materials without the therapist to provide presentation in a unique way. Therapists expect skills to be generalized, but this generalizability needs to be supported by the therapist, not only with instructions and suggestions to the other key adults who will be with the child, but also in the materials and activities being used. Therefore intervention sessions need to include the specific materials that we expect children to practice with when they are in other settings. These activities must be presented in ways that are reasonable for children to do on their own or with adults who are not therapists. An example of an activity that is commonly used in intervention but has little generalizability is a pegboard set. A child is unlikely to have a basic pegboard at home, and a pegboard is generally uninteresting to a child so it is not used in free play. In addition, the child is unlikely to have someone structure the presentation
of a peg to facilitate a finger pad grasp on the peg. Therefore it is suggested that although placement of pegs into a pegboard may be a reasonable activity for the motor skill element of therapy, a pegboard set may not be a good activity for engaging the child’s interest or for carryover into real-life situations. Involvement of parents or caretakers and teachers is almost always necessary for a child to integrate new skills into occupational tasks. This involvement needs to be more than asking others to carry out specific skills with the child. Parents and teachers “may need to modify their expectations of the child’s performance abilities” (Gilfoyle, Grady, & Moore, 1990, p. 259)
so the child is able to accomplish activities that are appropriate. To support the child’s performance of skills, the therapist must address the child’s environment, as well as the child’s ability to perform specific skills (Gilfoyle et al., 1990).
ADJUNCTS TO DIRECT INTERVENTION: SPLINTING, CASTING, AND CONSTRAINTINDUCED MOVEMENT THERAPY Using splinting or casting with children requires careful attention to precautions associated with these devices. Children may have less ability to report discomfort or changes in tone or function associated with the splint or other device, so preparation of the parent or guardian for use of the device and key factors to observe is important. Initially, close monitoring of the child’s status with the device is needed, thus leading to scheduling of frequent check-up sessions with opportunities to gather feedback from the parent or guardian and the child about the device and its impact on the child’s arm or hand, their comfort, and their functioning.
SPLINTING Hand splinting can be an effective adjunct to direct intervention for hand skills in children. Exner (2005) provides information about splinting in children, including a description of precautions and a summary of the various types of splints and their rationale. Additional information about splint types, and their uses and construction is provided by Gabriel and Duvall-Riley (2000) and Chapter 18. Research on the use of splinting in children is limited. In a research literature review analysis by Teplicky, Law, and Russell (2002) on the use of upper extremity splinting and
Intervention for Children with Hand Skill Problems • 263 casting with children, they identified a total of four studies that addressed hand splinting. Only two of the studies have been published since 1990. However, the literature suggests reasonable effectiveness of splinting for children with cerebral palsy, as all four of the studies reported positive outcomes relative to some aspect of upper extremity or hand control. Clearly this is an area for further study. Exner (2005) identified three broad categories of hand splints. A static splint may be most commonly used with children with the most severe disabilities. This type of splint sustains the wrist or one or more parts of the hand in a particular position. Static splints may be provided to support more normal posturing of the hand or prevent deformities. Some static splints have been used to allow for upper extremity weight bearing with a better hand position (Gabriel & DuvallRiley, 2000). Although children with moderate and even mild motor involvement may be provided with a static splint, they also may be provided with a dynamic splint or other orthotic device. Dynamic splints are designed to enhance the child’s movement at one or more of the joints within the hand. Other devices that are based on neurophysiologic principles for facilitating or inhibiting muscle activity may be placed on the child’s arm or hand. These devices may include the orthokinetic cuff, which is designed to facilitate extensor muscle activity and inhibit flexor muscle activity (Exner & Bonder, 1983) and the MacKinnon splint (Exner & Bonder, 1983; Flegle & Leibowitz, 1988; MacKinnon, Sanderson, & Buchanan, 1975).
CASTING Upper extremity casting for decreasing tone and improving hand function has been used in intervention with children with significant disabilities. Studies by Yasukawa (1992); Law et al. (1991); Tona and Schneck (1993); and Copley, Watson-Will, and Dent (1996) have shown some empiric support for this approach. A study by Law and associates (1997) used group experimental methodology to study the effect of occupational therapy treatment without casting to an intervention program that included casting. In this study, the benefits of including casting were not evident. Although changes may occur in tone or range of motion as a result of casting, changes in occupational performance may not (Russell & Law, 2003).
CONSTRAINT-I NDUCED MOVEMENT THERAPY Constraint-induced movement therapy and its applicability to children have resulted in a number of research studies in the past several years. This therapy is based on the work by Taub, in which he identified the issue
of “learned nonuse,” which refers to the lack of use of a more-involved upper extremity. In this case, the person has the ability to use the extremity to some degree, but finds use difficult or less than successful, so uses the arm even less. Thus skills are not developed to the ability level possible. In constraint-induced movement therapy, emphasis is placed on using the more involved upper extremity exclusively for a period of time; the less involved upper extremity is restrained via a constraint. Several single-subject studies (Crocker, MacKayLyons, & McDonnell, 1997; DeLuca et al., 2003; Glover et al., 2002) and small group comparison studies (Taub et al., 2004; Willis et al., 2002) have been conducted with children with cerebral palsy. The children in these studies ranged from approximately 1 to 8 years of age and had a splint or a cast placed on the less involved arm or hand for between 11 days (Glover et al., 2002) and 4 weeks (Willis et al., 2002), with 3 weeks being the most common time period (Crocker et al., 1997; DeLuca et al., 2003; Taub et al., 2004). Most of the children had this arm in the cast or splint while they were awake for 6 hours per day, except in the Willis and associates study, in which the children had the cast on their arms continuously for the month. The intervention for the more involved arm varied across the studies from several hours of highly specific intervention per day (Taub et al., 2004) to routine visits to occupational or physical therapy (Willis et al., 2002). In all of the studies, the children showed substantial change in functioning of the more involved upper extremity. Most studies reported continued improvement up to 6 months after the intervention. Although wearing the restraint was difficult periodically for some children and families (Glover et al., 2002) and dropout occurred in some studies (Crocker et al., 1997; Willis et al., 2002), meaningful gains in occupational performance were noted and valued by the families (Crocker et al., 1997; DeLuca et al., 2003; Taub et al., 2004; Willis et al., 2002). Clearly further research is needed on a number of dimensions of this therapeutic technique, which appears to have substantial promise.
SUMMARY Intervention for children with hand skill problems is guided by use of the occupational therapy framework, in which the overarching factor is the child’s ability to engage in occupational tasks with greater skill and thus more effectively fulfill desired roles. In approaching this intervention, many factors must be considered. The therapist—in collaboration with the child (whenever feasible), parent or guardian, teacher, and significant others—carefully assesses the child’s strengths and
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challenges and attempts to determine the major factors interfering with his or her ability to be successful in a variety of occupational tasks. If hand skill difficulties play a role in limiting the child’s functioning, the therapist seeks to delineate the problem areas and the child’s potential for improvement in skills. Needs for hand skills intervention must be balanced with other types of priorities that could be addressed by the therapist and the child’s other life needs and interests, such as academic skills, social skills, and play. In this process the therapist determines the child’s need for direct intervention designed to improve hand skills and the child’s need for any adaptations or compensatory strategies to assist in accomplishing daily life tasks. The child’s perceptual and cognitive functioning affect this planning, because hand skills are intimately related to the child’s perception of objects and space and his or her desire to accomplish a meaningful end goal. To assist in determining the child’s potential for improvement from direct intervention for specific hand skills, the therapist needs information that typically cannot be derived solely from standardized tests of fine motor skills. For realistic intervention designed to improve the child’s hand skills the therapist must consider the skills that are within reach for the child. Determining this range of skills within reach may be called identifying the child’s “zone of proximal development.” Hand skills intervention typically integrates a variety of strategies, which depend upon the child’s overall motor problems and skills, as well as the child’s particular problems in hand function. Given the critical role that tactile-proprioceptive perception play in the use of hand skills, addressing this area may be an important aspect of intervention. Physical handling to enhance the child’s performance may be used with many of the intervention strategies. Verbal cuing for the type of motor action desired and verbal reinforcement for performance of particular motor skills is appropriate for almost all children. Repetition of actions is necessary for building skill in new motor patterns, so games and imaginative activities that engage the child’s interest and sustain the child’s performance of the activities are useful. Because hand skill activities must be done with the child’s active participation and cannot be done to the child, the child’s interest and motivation to engage in the activities is very important. Although children often respond well to initially trying out new skills in a one-on-one situation with a therapist, opportunities to practice and use skills in a variety of settings and a variety of activities is an important consideration. Therefore collaboration with the child, the parents or caregivers, and teachers is crucial in helping the child develop hand skills that can be spontaneously used to enhance the child’s performance in a variety of daily life skills.
REFERENCES Barnes KJ (1986). Improving prehension skills of children with cerebral palsy: A clinical study. Occupational Therapy Journal of Research, 6:227–240. Barnes KJ (1989a). Relationship of upper extremity weight bearing to hand skills of boys with cerebral palsy. Occupational Therapy Journal of Research, 9:143–154. Barnes KJ (1989b). Direct replication: Relationship of upper extremity weight bearing to hand skills of boys with cerebral palsy. Occupational Therapy Journal of Research, 9:235–242. Beckung E, Steffenburg U, Uvebrant P (1997). Motor and sensory dysfunctions in children with mental retardation and epilepsy. Seizure, 6:43–50. Boehme R (1988). Improving upper body control: An approach to assessment and treatment of tonal dysfunction. Tucson, AZ, Therapy Skill Builders. Bumin G, Kayihan H (2001). Effectiveness of two different sensory integration programmes for children with spastic diplegic cerebral palsy. Disability and Rehabilitation, 23(9):394–399. Case-Smith J (1991). The effects of tactile defensiveness and tactile discrimination on in-hand manipulation. The American Journal of Occupational Therapy, 45:811–818. Case-Smith J (2000). Effects of occupational therapy services on fine motor and functional performance in preschool children. The American Journal of Occupational Therapy, 54(4):373–380. Case-Smith J, Fisher AG, Bauer D (1989). An analysis of the relationship between proximal and distal motor control, The American Journal of Occupational Therapy, 43:657–662. Copley J, Watson-Will A, Dent K (1996). Upper limb casting for clients with cerebral palsy: A clinical report. Australian Occupational Therapy Journal, 43:39–50. Croce R, DePaepe J (1989). A critique of therapeutic intervention programming with reference to an alternative approach based on motor learning theory. Physical and Occupational Therapy in Pediatrics, 9(3):5–33. Crocker MD, MacKay-Lyons M, McDonnell E (1997). Forced use of the upper extremity in cerebral palsy: A single case design. The American Journal of Occupational Therapy, 5:824–833. Cronin AF (2004). Mothering a child with hidden impairments. The American Journal of Occupational Therapy, 58(1):83–92. Curry J, Exner C (1988). Comparison of tactile preferences in children with and without cerebral palsy. The American Journal of Occupational Therapy, 42(6):371–377. DeGangi GA, Wietlisbach S, Goodin M, Scheiner N (1993). A comparison of structured sensorimotor therapy and child-centered activity in the treatment of preschool children with sensorimotor problems. The American Journal of Occupational Therapy, 47:777–786. DeLuca SC, Echols K, Ramey SL, Taub E (2003). Pediatric constraint-induced movement therapy for a young child with cerebral palsy: Two episodes of care. Journal of the American Physical Therapy Association, 83:1003–1013. Eliasson AC, Gordon AM (2000). Impaired force coordination during object release in children with hemiplegic cerebral palsy. Developmental Medicine and Child Neurology, 42:228–234. Erhardt R (1992). Eye-hand coordination. In J Case-Smith, C Pehoski, editors: Development of hand skills in the child.
Intervention for Children with Hand Skill Problems • 265 Rockville, MD, The American Occupational Therapy Association. Exner CE (1990a). In-hand manipulation skills in normal young children: A pilot study. Occupational Therapy Practice, 1(4):63–72. Exner CE (1990b). The zone of proximal development in in-hand manipulation skills of nondysfunctional 3- and 4year-old children. The American Journal of Occupational Therapy, 44:884–891. Exner CE (1992). In-hand manipulation skills. In J CaseSmith, C Pehoski, editors: Development of hand skills in the child (pp. 35–45). Rockville, MD, The American Occupational Therapy Association. Exner CE (2005). Development of hand skills. In J CaseSmith, editor: Occupational therapy for children, 5th ed. (pp. 304–355). St Louis, Elsevier. Exner CE, Bonder BR (1983). Comparative effects of three hand splints on the bilateral hand use, grasp, and armhand posture in hemiplegic children: A pilot study. Occupational Therapy Journal of Research, 3:75–92. Exner CE, Henderson A (1995). Cognition and motor skill. In A Henderson, C Pehoski, editors: Hand function in the child: Foundations for remediation (pp. 93–110). St Louis, Mosby. Fedrizzi E, Pagliano E, Andreucci E, Oleari G (2003). Hand function in children with hemiplegic cerebral palsy: Prospective follow-up and functional outcome in adolescence. Developmental Medicine and Child Neurology, 45:85–91. Flegle JH, Leibowitz JM (1988). Improvement in grasp skill in children with hemiplegia with the MacKinnon splint. Research in Developmental Disabilities, 9(2):145–151. Gabriel L, Duvall-Riley B (2000). Pediatric splinting. In B Coppard, editor: Introduction to splinting: A critical reasoning & problem solving approach (pp. 396–443). San Diego, Technical Books. Gilfoyle EM, Grady AP, Moore JC (1990). Children adapt, 2nd ed. Thorofare, NJ, Slack. Glover JE, Mateer CA, Yoell C, Speed S (2002). The effectiveness of constraint-induced movement therapy in two young children with hemiplegia. Pediatric Rehabilitation, 5:125–131. Goodman G, Bazyk S (1991). The effects of a short thumb opponens splint on hand function in cerebral patsy: A single-subject study. The American Journal of Occupational Therapy, 45:726–731. Gordon AM, Duff SV (1999). Relation between clinical measures and fine manipulative control in children with hemiplegic cerebral palsy. Developmental Medicine and Child Neurology, 41:586–591. Gordon AM, Lewis SR, Eliasson A-C (2003). Object release under varying task constraints in children with hemiplegic cerebral palsy. Developmental Medicine and Child Neurology, 45:240–248. Hirschel A, Pehoski C, Coryell J (1990). Environmental support and the development of grasp in infants. The American Journal of Occupational Therapy, 44:721–727. Humprey R, Jewell K, Rosenberger RD (1995). Development of in-hand manipulation and relationship with activities. American Journal of Occupational Therapy, 49:763–774. Hung YC, Charles J, Gordon AM (2004). Bimanual coordination during a goal-directed task in children with hemiplegic cerebral palsy. Developmental Medicine and Child Neurology, 46(11):746–753.
Krumlinde-Sundholm L, Eliasson AC (2002). Comparing tests of tactile sensibility: Aspects relevant to testing children with spastic hemiplegia. Developmental Medicine and Child Neurology, 44:604–612. Law M, Cadman D, Rosenbaum P, Walter S, Russell D, DeMatteo C (1991). Neurodevelopmental therapy and upper-extremity inhibitive casting for children with cerebral palsy. Developmental Medicine and Child Neurology, 33:379–387. Law M, Russell D, Pollock N, Rosenbaum P, Walter S, King G (1997). A comparison of intensive neurodevelopmental therapy plus casting and a regular occupational therapy program for children with cerebral palsy. Developmental Medicine and Child Neurology, 39:664–670. Lawrence DG, Kuypers HG (1968a). The functional organization of the motor system in monkey. I. The effects of bilateral pyramidal lesions. Brain, 91:1–14. Lawrence DG, Kuypers HG (1968b). The functional organization of the motor system in monkey. II. The effect of lesions of the descending brainstem pathways. Brain, 91:15–36. MacKinnon J, Sanderson E, Buchanan J (1975). The MacKinnon splint. A functional hand splint. Canadian Journal of Occupational Therapy, 42:157–158. McHale K, Cermak SA (1992). Fine motor activities in elementary school: Preliminary findings and provisional implications for children with fine motor problems. The American Journal of Occupational Therapy, 46:898–903. Missiuna C, Pollock N (2000). Perceived efficacy and goal setting in young children. Canadian Journal of Occupational Therapy, 67(2):101–109. Nichols DS (2005). Development of postural control. In J Case-Smith, editor: Occupational therapy for children, 5th ed. (pp. 278–303). St Louis, Elsevier. Noronha J, Bundy A, Groll J (1989). The effect of positioning on the hand function of boys with cerebral palsy. The American Journal of Occupational Therapy, 43:501–512. Nwaobi OM (1987). Seating orientations and upper extremity function in children with cerebral palsy. Physical Therapy, 67:1209–1212. Occupational Therapy Practice Framework (2002). Domain and process. The American Journal of Occupational Therapy, 56(6):609–639. Paillard J (1990). Basic neurophysiological structures of eyehand coordination. In C Bard, M Fleury, L Hay, editors: Development of eye-hand coordination across the life span. Columbia, SC, University of South Carolina Press. Pehoski C (1992). Central nervous system control of precision movements of the hand. In J Case-Smith, C Pehoski, editors: Development of hand skills in the child (pp. 1–11). Rockville, MD, The American Occupational Therapy Association. Pehoski C (2005). Cortical control of hand-object interaction. In A Henderson, C Pehoski, editors: Hand function in the child: Foundations for remediation (pp. 3–15). St Louis, Mosby. Pehoski C, Henderson A, Tickle-Degnen L (1997a). Inhand manipulation in young children: Rotation of an object in the fingers. American Journal of Occupational Therapy, 51:544–552. Pehoski C, Henderson A, Tickle-Degnen L (1997b). Inhand manipulation in young children: Translation movements. American Journal of Occupational Therapy, 51:719–728.
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Ruff HA (1984). Infants’ manipulative exploration of objects: Effects of age and object characteristics. Developmental Psychology, 20:9–20. Russell D, Law M (2003). Casting-splinting-orthoses. Retrieved December 30, 2003 from http://www.fhs.mcmaster.ca/canchild/publications/keep current/KC95-2.html Schoemaker MM, Niemeijer AS, Reynders K, SmitsEngelsman BC (2003). Effectiveness of neuromotor task training for children with developmental coordination disorder: A pilot study. Neural Plasticity, 10:155–163. Seeger BR, Caudrey DJ, O’Mara NA (1984). Hand function in cerebral palsy: The effect of hip-flexion angle. Developmental Medicine and Child Neurology, 26:601–606. Skold A, Josephsson S, Eliasson A-C (2004). Performing bimanual activities: The experience of young persons with hemiplegic cerebral palsy. The American Journal of Occupational Therapy, 58(4):416–425. Smelt HR (1989). Effect of an inhibitive weight-bearing mitt on tone reduction and functional performance in a child with cerebral palsy. Physical and Occupational Therapy in Pediatrics, 9(2):53–80. Smith-Zuzovsky N, Exner C (2004). The effect of seated positioning quality on typical 6- and 7-year-old children’s object manipulation skills. The American Journal of Occupational Therapy, 58(4):380–388. Stiller C, Marcoux BC, Olson RE (2003). The effect of conductive education, intensive therapy, and special education services on motor skills in children with cerebral palsy. Physical and Occupational Therapy in Pediatrics, 23:32–50. Swart SK, Kanny EM, Massagli TL, Engel JM (1997). Therapists’ perceptions of pediatric occupational therapy interventions in self-care. The American Journal of Occupational Therapy, 51:289–296.
Taub E, Ramey SL, DeLuca S, Echols K (2004). Efficacy of constraint-induced movement therapy for children with cerebral palsy with asymmetric motor impairment. Pediatrics, 113(2):305–312. Teplicky R, Law M, Russel D (2002). The effectiveness of casts, orthoses, and splints for children with neurological disorders. Infant and Young Children, 15(1):42–50. Tona JL, Schneck CM (1993). The efficacy of upper extremity inhibitive casting: A single-subject pilot study. The American Journal of Occupational Therapy, 47:901–910. Vygotsky LS (1978). Mind in society: The development of higher psychological processes. Cambridge, MA, Harvard University Press. Weinstock-Zlotnick G, Hinojosa J (2004). Bottom-up or top-down evaluation: Is one better than the other? The American Occupational Therapy Association. 58(5):594–599. Willis JK, Morello A, Davie A, Rice JC, Bennett JT (2002). Forced-use treatment of childhood hemiparesis. Pediatrics, 110:94–96. Yasukawa A (1992). Upper-extremity casting: Adjunct treatment for the child with cerebral palsy. In J CaseSmith, C Pehoski, editors: Development of hand skills in the child. Rockville, MD, The American Occupational Therapy Association. Yekutiel M, Jariwala M, Stretch P (1994). Sensory deficit in the hands of children with cerebral palsy: a new look at assessment and prevalence. Developmental Medicine and Child Neurology, 36:619–624. Yim SY, Cho JR, Lee IY (2003). Normative data and developmental characteristics of hand function for elementary school children in Suwon area of Korea: Grip, pinch and dexterity study. Journal of Korean Medical Science, 18:552–558.
Chapter
13
A FINE MOTOR PROGRAM FOR PRESCHOOLERS Carol Anne Myers*
CHAPTER OUTLINE VERTICAL SURFACES MANIPULATIVES The Manipulatives Program Fine Motor Planning SCISSORS DRAWING AND WRITING Hand Preference Activities to Help Develop Pencil Grasp and Control WHAT MAKES THERAPY EFFECTIVE? CASE STUDY
The activities and suggestions included in this chapter were developed at the Newton Early Childhood Program (formerly the Brookline-Newton Early Childhood Collaborative) in the metropolitan area of Boston. The program serves preschoolers from 3 through 5 years of age with mild to severe special needs. This chapter focuses primarily on activities that are used with children who have mild to moderate special needs, but in some cases they may be adapted for use with children who have severe needs. Occupational therapy (OT) services in the Newton Early Childhood Program are provided to children who attend integrated preschool classrooms (a combination of typically developing children and children who have with special needs), in substantially separate *Taken in part from Myers CA (1992). Therapeutic fine-motor activities for preschoolers. In J Case-Smith, C Pehoski, editors: Development of hand skills in the child. Rockville, MD, American Occupational Therapy Association.
self-contained class-rooms, as well as to children who attend community nursery schools. The children who are in community nursery schools usually receive related services such as speech and language, OT, and physical therapy during their after-school hours. Many of the children who receive OT services have learning differences that may result in a learning disability diagnosis in later years, or mild to moderate sensory processing difficulties. Some of the children who receive OT, however, have no area of disability other than a discrete weakness in fine motor skills. Although the program is comprehensive in the types of OT intervention that are provided, this chapter focuses on the fine motor program, which refers both to the use of manipulatives, as well as to prewriting skills such as the use of scissors and drawing implements. The theoretical rationale for the fine motor program described in this chapter is based primarily on the work of Mary Benbow, as gleaned from her workshops and publications (see Chapter 15). Her perspective has provided an invaluable foundation on which to base the work of the program. Many of her ideas for fine motor activities with older children have been adapted for the work with preschool children. The philosophy of the fine motor program is based on the classic OT theory that intervention should enhance the client’s ability to participate in his or her “occupation,” which has “long been recognized as a requirement for survival and, to varying degrees, as a source of pleasure” (Hopkins & Smith, 1978).
The occupation of the preschool child is to be independent and successful in all of the areas of the classroom and playground, both with play activities as well as with self-care. Specifically in respect to fine
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motor skills, the overall goal is for students to be able to participate productively in classroom learning centers such as the art area, manipulatives area, and writing center. Young preschoolers work at mastering a variety of manipulatives and simple art projects, whereas older preschoolers develop the skills to independently use complex, multistep manipulatives, and to participate in multistep art projects as well as prewriting tasks. Parents and teachers often overemphasize prewriting activities for young preschoolers, while short-changing them on the use of manipulatives that will develop their overall hand function. This overemphasis on “academics” may have been encouraged by the overall national trends toward increased standardized testing of students of all ages. Windsor (2000) stated that “at the preschool level, tool use … and ‘whole body’ play in the environment are preferred to practice with pencils, pens, and tabletop exercises” (p. 19).
It is critical for parents of students in the program to understand that all aspects of hand development are valuable, and that the provision of a rich variety of manipulative materials will benefit all students as they move toward developing prewriting skills. To fully assist students in being functional and independent with all of the classroom activities, therapists either use materials that are similar to classroom materials, or they borrow materials from the classroom for the OT sessions. This practice enhances the generalization of skills learned during the OT sessions to the classroom setting, and is particularly applicable in two circumstances: (a) students who avoid fine motor areas in the classroom because of low self-confidence, and (b) students with fine motor planning difficulties. Most of the children in the program who receive OT services to address fine motor delays receive them once weekly, for 30 minutes, in either an individual or small group setting. The ideal arrangement is to schedule sessions with pairs of children who have been carefully matched by age and by specific needs. Case-Smith (2000) found that
“the most surprising finding [in the study] was that the therapist’s use of play and peer interaction predicted the fine motor outcomes and that among the intervention variables, play and peer interaction were the only significant predictors” (p. 378).
In addition to providing direct services to students, the occupational therapists consult with parents and classroom teachers. Once a child is comfortable with the activities in the therapy settings (usually after 6 to 8 weeks), therapists typically provide recommendations to the child’s classroom teachers and sometimes recommend that the parents provide a modified home program. Parents should not attempt to mimic the role of the therapist or teacher; rather, parents provide appropriate materials and naturalistic, enjoyable opportunities for the child to demonstrate and use at home the skills that have been learned in therapy and school. Surrounding the child with a team of people who are familiar with the child’s strengths and weaknesses and who understand the goals of the intervention program greatly enhances the therapy process.
VERTICAL SURFACES Vertical and slant board surfaces are an extremely important part of the fine motor program. Benbow (1995) emphasized the importance of working on a vertical surface to encourage appropriate hand and wrist position for fine motor and handwriting skills. Both vertical and slant board surfaces correctly position the wrist in extension, which supports thumb abduction so that the thumb can work skillfully with the fingertips. Stable wrist extension and thumb opposition also facilitate total arching of the hand for skillful manipulation of objects. Therefore, providing a vertical or slant board work surface is an important modification that parents and teachers can incorporate as they work or play with the child. Activities performed above eye level on vertical or near-vertical work surfaces such as floor and table easels promote
“occupational therapists’ use of play activities and peer interaction were important predictors of [fine motor] skill levels at the end of the year” (p. 379).
“wrist stabilization in extension with precision finger skills” (Benbow, 1995, p. 257),
Pairing children for OT sessions provides structure as well as peer support to encourage success with challenging activities. Having two students work together also enhances the therapist’s ability to make the activities seem like games rather than exercises. In a study examining performance outcomes for OT that addressed fine motor skills, Case-Smith (2000) noted that
as well as the development of arm and shoulder muscles. Whenever possible, teachers are encouraged to provide activity areas in which the children are working upright (sitting, kneeling, or standing) with their arms and hands moving against gravity at an easel or other vertical work surface, rather than leaning over small tables. When children work on a horizontal surface,
A Fine Motor Program for Preschoolers • 269 BOX 13-1
Some Examples of Activities for Use on a Vertical Surface
1. Making pictures with stickers. 2. Colorforms or Unisets (these activities provide a board on which to arrange reusable plastic “stickers,” and they are available in a wide variety of themes and designs). 3. Feltboards or flannel boards, which permit the placement of figures depicted in stories or scenes created by the child. 4. Magnet letters or shapes on a magnet board (available in story themes as well). 5. Chalkboards: Use sidewalk chalk (wide-diameter chalk) broken into 11⁄2- to 2-inch pieces for children to hold with the tips of the thumb, index finger, and middle finger. In one favorite activity, the child draws a design with the chalk and then uses a paintbrush with water to “magically” erase the design. 6. Geoboards (rubber band designs created on a grid of nails). 7. Painting or drawing. 8. Ink stamping activities. 9. Pegboards, many different varieties (Lite Brite Cube uses small pegs and by design is oriented on the vertical).
they often place their wrists in neutral or flexion, which does not promote skillful use of the intrinsic muscles. Switching activities from a horizontal to a vertical orientation can transform an ordinary or mediocre activity into a powerful tool for encouraging fine motor skill development. Many activities can be oriented on the vertical by placing the materials (e.g., geoboard) on the lower lip of a tabletop easel. In the Newton Early Childhood Program, children are expected to work regularly on vertical work surfaces. With a minimal amount of modification and equipment expense, many activities can be adapted easily for use on a vertical surface (Box 13-1). It is beneficial for the shoulder, arm, wrist, and hand development of all preschoolers to work on activities at a vertical or near-vertical surface on a regular basis. For older preschoolers who are working on representative drawing and writing letters, students use a slant board that is at an estimated angle of 20 degrees. A low-cost way to provide multiple slant board surfaces in a classroom is to place 3-inch three-ring binders at the writing table; the ring side of the binder is placed horizontally toward the middle of the table so that the slope of the binder slants down toward the edge of the table where the student is sitting. The students use these slant board binders as drawing and writing surfaces. They are relatively inexpensive, and are easy for teachers to store when the writing center is being used
Figure 13-1 Tripod grasp with extended wrist, and forearm resting on the surface of a 20-degree slant board.
for a different purpose. Parents also have used these binders as slant boards at home, and often purchase a three-hole zipper storage bag that can hold the child’s markers inside the binder for traveling. A variety of more sophisticated alternatives are available from many sources, some of which are listed in the Appendix. Because it is recommended that students use a slant board surface well beyond their preschool years, many parents opt to purchase a more permanent work surface, such as Write-Slant Boards, which provide a helpful clip at the top to stabilize the paper. The reason older preschool students draw and write on the 20-degree slant board instead of the vertical or near-vertical surfaces is because the 20-degree angle encourages students to rest their hand and forearm on the work surface, whereas the vertical and near-vertical surfaces do not. With the older students, therapists are encouraging the development of a tripod or quadrupod grasp, with accompanying intrinsic muscle movements of the fingers while drawing or writing, which means that the hand and forearm must rest on the table (Figure 13-1). Having parents and teachers provide a 20-degree slanted work surface helps students to make the transition from drawing with their hands off the table to drawing and writing with their hands resting on the table, as expected. Although older students in elementary school may have developed the appropriate mature writing grasp, a slant board encourages the ideal posture—an erect spine—while drawing or writing and enhances students’ endurance for completing lengthy homework assignments. For therapists who are attempting to demonstrate the value of vertical or slant board surfaces to parents or teachers, it is helpful to ask children to perform a task such as a pegboard or a drawing activity on a horizontal surface, and then ask them to perform the same activity on a vertical surface. The difference in the child’s hand position and ability is often dramatically evident in such a demonstration. Observing that
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difference first-hand helps parents and teachers to understand why working on the vertical is so valuable. Examples throughout this chapter illustrate how working on the vertical or slant board surface maximizes the therapeutic benefit of the activities.
MANIPULATIVES Young children, especially 3-year-olds, should spend more time with fine motor manipulatives than writing utensils. Sometimes parents and teachers feel that young children should begin to “practice” with pencils and markers, but this early practice may result in a poor pencil grasp, partially because children may be asked to use writing utensils before their hands are ready for that kind of refined activity. Benbow (1995) specifically noted that boys tend to avoid fine motor activities in lieu of computer games, while girls who practice with writing implements at an early age “without proper adult attention or supervision” may then “adopt pencil grips that are inefficient or even harmful” (p. 255).
Benbow (1988) further noted that “pencil postures ‘fixed’ early by repeated use at an intermediate level of skill will later affect negatively on graphomotor performance when speed and volume demands increase” (p. v).
Therefore children should be developing their hands for a variety of activities in a variety of positions before they are expected to draw or write with the proper grasp. In preparation for writing, the hand progresses through the following motor milestones (Benbow, 1995): 1. Development of wrist stabilization in extension to support skilled finger movements. 2. Development of a stable open index finger-thumb web space when performing skilled activities. The open web space should have a circular shape. This position is frequently compromised in children who have hyperextension of the interphalangeal joint of the thumb; rather than a circular web space; these children form a “crescent moon” with a small opening. The thumb is in a fixed position, thereby making intrinsic muscle activity difficult (Figure 13-2). Children with this problem must be monitored carefully when they perform fine motor activities to find those activities that encourage the use of the thumb in a flexed position. 3. Development of palmar arches in the hand, represented by a concave surface on the palm. 4. Development of an awareness of the “skill side” of the hand; this means that the child consistently orients skilled activities toward the thumb, index
Figure 13-2 Hyperextended thumb and compromised web space on lace tip.
finger, and middle finger. These three fingers are hereafter called the “skill fingers.” 5. Development of intrinsic muscle movement in the fingers; this kind of fine muscle movement can be seen when the ulnar side of the hand is stabilized on the table while the fingers move a pencil to write, or when the fingers make fine movements to thread a needle. The intrinsic movements are best observed in activities that require the tips of the thumb, index finger, and middle finger to be touching while they are performing small movements of midrange flexion and extension of the metacarpal-phalangeal (MCP) joints. Many so-called “fine motor” activities involve the use of the hands and fingers, but do not necessarily elicit the fine motor movements of the intrinsic muscles at the MCP joints. One example of an activity that parents often cite as proof of their child’s fine motor abilities is the use of a computer mouse. The use of a mouse involves primarily the arm and shoulder muscles, with slight flexion of the index finger for clicking the mouse. (In cases in which the mouse has a scroll wheel, the middle finger does use some intrinsic muscle movement to scroll, although students usually point and click more often than they scroll.) Although skilled use of a mouse is difficult for children with overall upper extremity motor control issues, many students with significantly reduced fine motor skill with manipulatives are able to successfully use a mouse. That is because the mouse does not require the skilled use of the intrinsic muscles of the skill fingers working together with an open thumb-index finger web space; it falls short as a fine motor activity. Adding insult to injury, instead of using their hands to work a variety of real puzzles, many preschool students with poor fine motor skills work puzzles on computer screens. Parents and teachers of children who have poor fine motor skills are strongly encouraged to limit the child’s time on the computer, and increase the availability of a variety of concrete materials that will encourage fine motor skill development.
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THE MANIPULATIVES PROGRAM The primary components of an OT session include Wake Up Hands, Strong Hands, and Smart Hands. Therapists’ regular use of these positive phrases is powerful for students, who quickly learn to use them to identify the attributes of their activities. Many of the classroom teachers also provide Wake Up Hands activities before beginning a fine motor or prewriting tabletop activity with the older preschoolers.
Wake Up Hands Wake Up Hands activities provide sensory stimulation to the hands, including tactile stimulation as well as proprioceptive/kinesthetic stimulation, resulting in overall readiness for later activities. A wide variety of soft objects, including gel-filled balls, rubber animals, and countless other items are used during Wake Up Hands. Activities include squeezing the objects, rolling them on the table, rolling them all over the hands (with each hand taking turns), grabbing them with the thumb and index finger (pincer grasp), poking them with either the thumb or index finger, and using them isometrically by having both hands press the object. Students also perform a variety of motions with their hands such as clapping, rubbing, or shaking. A variety of textures might be provided through materials such as unscented lotion, powder (including dry Jell-O powder), and fabrics from rough to smooth. The therapists also provide rubber bands or elastic sewn into circles of various sizes so that students can perform a variety of pulling activities, one finger at a time. Students seem to particularly enjoy placing the rubber band in a way that “traps” their fingers, and they enjoy moving their fingers against the resistance while pretending to escape from the rubber band trap. TheraBand and Thera tubing also can be used for pulling and stretching activities during Wake Up Hands. One of the most popular Wake Up Hands activities is the accordion tubes, sometimes called “rapper snappers.” These tubes provide excellent resistance to finger, arm, and shoulder muscles when students expand the tubes, and provide similar input when they are manually contracted to become small again (Figure 13-3). During a game, the tubes can be called caterpillars; therapists ask students to pretend they are turning baby caterpillars into big ones, and then back into babies. For a whole-body motion that provides an excellent motor break before a tabletop session, students pair up and connect their accordion tubes. They then make the caterpillars “pop” by pulling, tug of war style, on their respective tubes until the tubes come apart with a large popping sound. From a safety perspective, be sure that the students have enough space for this activity, as some of the smaller students literally fall backward from the momentum until they
Figure 13-3
Accordion tube toys (“rapper snappers”).
Figure 13-4 tube toys.
The “caterpillar pop” game using accordion
learn how to position their feet effectively to brace themselves. This activity can be repeated for several minutes, as students select a new partner for each caterpillar pop (Figure 13-4). All of the preceding materials are used for sensory stimulation and also for basic practice with motor planning or imitation games. The therapist demonstrates the movement, and the children imitate it. For example, the teacher or occupational therapist can bend the tube into a variety of shapes, which the students must then imitate with their own accordion tube. Representative shapes are best, such as an elephant’s trunk, telephone receiver, window, or crown, so that the children can concretely imagine a use for each new shape. After a few examples provided by an adult, students enjoy coming up with their own shapes to suggest. Meanwhile, all of the students’ fingers, hands, and arms are being stimulated in a positive, enjoyable way.
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Another Wake Up Hands activity is “putting on your [imaginary] power gloves,” which students can either do for themselves or have done by an adult. To put on the “gloves,” each finger is grasped at the fingertip by the thumb and index finger of the other hand, and gentle pressure is exerted as the thumb and index finger slowly travel down to the base of the finger. Each finger is stimulated in turn until all 10 are complete, at which point the “gloves” have been put on. This provides both tactile and proprioceptive stimulation, and also provides a mental image of powerful hands that is a good mindset for students preparing for a fine motor task. It is, of course, a more powerful sensation for an adult to provide the stimulation than for the children to provide it for themselves, although with a large group sometimes it is impossible for an adult to get around to each child in a timely fashion. Wake Up Hands with 4- and 5-year old children often includes two components: the primarily sensory component with the soft objects and varied textures, and a higher-level demand such as finger plays. Many of the students have difficulty isolating individual fingers, and also with imitation and fine motor planning. Carefully chosen finger plays tend to be motivating for them, and observing students performing finger plays is an excellent way to quickly learn a great deal about their current level of hand development. Choose finger plays that include developmentally appropriate finger motions such as the following: forming a circle with the thumb and index finger, isolating the index finger or the thumb, or forming a cupped palm (see Appendix for a good source of finger plays). Many young students have difficulty forming a circle with their thumb and index finger; the circle tends to be flattened rather than round. These are often the same students who have difficulty forming an open thumb-index finger web space with drawing implements. The finger plays provide an additional way for students to practice using their fingers in a variety of positions, and a way for the therapist to visually gauge their progress. For students for whom the combination of language and motor planning demands is too high, therapists have them practice the motor component of a finger play separately before adding the language component.
Strong Hands Although activities from any of the three components of a therapy session may address multiple areas of development, the rationale for labeling the activity is to help students understand its primary goal. The use of these specific terms has provided unexpected benefits, particularly the use of the term “Strong Hands.” The students with less than average hand grasp strength are often the students who are least likely to take risks with novel fine motor tasks. When “Strong Hands” is
presented as a regular activity, students quickly learn to view their hands as strong. Verbal encouragement (e.g., “Look how strong you are. You made the rocket fly across the table!”) helps students to believe that they can become stronger through games and activities. Students actually enter a session enthusiastically asking, “What are we doing for Strong Hands today?” When students have less than average hand grasp strength, their parents and teachers are encouraged to provide hand strengthening activities naturalistically throughout the week. Therapists provide beneficial activities and attitude boosting encouragement, but children should become stronger through daily activities that are a natural part of their routine. A first step for many teachers and parents is to discontinue the practice of performing a task for the child if the child is not able to perform it for himself or herself. Adults are asked to say, “Let’s do it together” rather than “Let me help you.” Even if the adult provides most of the power for the task, having the child do even part of it helps to develop the motor plan for the task and allows the child to use whatever level of strength is available to assist. A common example of this situation occurs in the classroom when students bring a snack from home. Many of the individually wrapped snacks that parents send in with students, in fact, are challenging even for adults to open. When necessary, adults open these containers hand-over-hand with the students, both to assist them as well as to gauge for themselves how difficult the task really is. When students are empowered by participating in the task from the start, they are much more likely to perform the task independently in the future. Activities to encourage hand strength are listed in Box 13-2. In addition to these ideas, strength-based toys including classroom building toys such as Duplos and Bristle Blocks also are valuable. Furthermore, therapists can use a variety of different containers to encourage the development of both strength and skill. For example, the OT clinic has a large collection of cookie tin–style containers of varying resistance, and materials often are placed inside the containers ahead of time. One of the activities in the session is for the children to open their own containers to see what materials will be used for the next activity. In addition to cookie tin containers, therapists use a variety of zipper containers, screw-top jars of all sizes, Rubbermaid containers, plastic lunch boxes, and many others to challenge children’s hands in a variety of functional ways. Using different kinds of containers, with the expectation that what’s inside will be new or interesting each week, has provided excellent motivation for students who were previously reluctant to attempt opening containers on their own. Hand-over-hand assistance is provided at just the right level to encourage students to do as much as they can by themselves.
A Fine Motor Program for Preschoolers • 273 BOX 13-2
Activities to Encourage Hand Strength
1. Play Dough a. Use a garlic press to make “spaghetti.” b. Use rolling pins to make pretend cookies (shoulder and arm strength). c. Press cookie cutters into flattened play dough. d. Find hidden objects such as pegs, marbles, or toys. Note: Crayola Model Magic or clay also can be used, depending on how much resistance is desired. Homemade play dough provides less resistance than the commercial variety. 2. Water sprayers (e.g., those found in a drug store for “spritzing” hair) a. Spray water onto pictures drawn with markers to make them “melt.” (Note: This activity works best if the markers are relatively new and the drawing has just been completed.) b. Spray a mixture of water and food coloring to color snow (in northern climates). c. Spray plants or outdoor bushes. d. Spray the walls while in the bathtub, with the shower curtain partially closed. 3. Geoboards: This is a grid of nails or plastic points. Use rubber bands of varying thicknesses to create designs, or use nylon potholder loops for less resistance. (Cotton cloth loops often are too thick to successfully stay on the points.) 4. Newspapers: Tear newspapers to stuff a scarecrow or other classroom project. 5. Wringing out sponges or washcloths (e.g., as part of a clean-up activity, or in the bathtub). 6. Squeeze toys such as the Swinging Monkey and the Flying Fist (see Appendix for sources).
Smart Hands Smart Hands manipulative activities typically emphasize multiple skills within one activity. For example, using a wind-up toy encourages isolated use of the thumb and index finger, but may also require a significant amount of finger strength, depending on the resistance of the particular wind-up toy and on the shape of the winding knob or key. It is important for therapists to be familiar enough with their manipulatives to know which ones are appropriate for 3-yearolds, and which ones are more appropriate for 4- or 5-year-olds. Classroom teachers often need guidance about this as well. Some of the classroom building manipulatives require more eye-hand coordination than is expected for the typical 3-year-old, and if teachers expect and encourage students to participate in a too-demanding activity, students may begin to feel that they are not successful with manipulatives. When referring specifically to in-hand manipulation, Case-Smith (1995) stated that
“practice of a component skill (e.g., translation) may or may not generalize into improved functional performance (e.g., ability to button). Although task analysis demonstrates that a similar movement pattern is necessary in object translation and buttoning, the therapist cannot assume that in-hand manipulation skill will generalize to the task” (pp. 773–774).
Therefore the therapists provide activities that are not just “OT materials,” but also provide direct experience with typical, age appropriate classroom manipulatives. Although therapeutic activities that address the component skills of a task are beneficial, for the most successful transfer of learning and skills to the classroom setting, preschool students need the concrete experience of learning to use specific classroom manipulatives within the OT session. Following is a list of some of the most popular Smart Hands activities and manipulatives used in the program: 1. Play dough (bilateral coordination, fine motor planning, skilled finger use): Play dough can provide excellent strengthening activities for preschool students, but also can be used to encourage the development of skills. The following activities are used with students who are ready for more skilled use of play dough: a. Drawing in flattened play dough using a peg, b. Rolling play dough balls: There are three levels of difficulty available for this activity: (a) using one hand and rolling the play dough on the table, (b) rolling the play dough between two hands in the air, or (c) using the thumb, index finger, and middle finger to roll a small ball, and c. Using play dough to make representative objects (e.g., rolling a “snake” form and decorating it with different colors and sizes of pegs to create a caterpillar; rolling balls and stacking them to make a snowman, drawing the facial features and buttons using a small stick peg, and then adding two stick pegs for the arms). As students become more skilled in their ability to make a variety of shapes, their ability to create complex creations will increase. Another variation is to use small toys with the play dough (e.g., small plastic babies from the baby shower section of a party store inspired students to make cribs, playpens, diapers, and many other representative objects from play dough to use with the babies). 2. Stringing/lacing activities (skilled grasp patterns, eye-hand coordination, bilateral use of hands): Of all the manipulative activities available to the students, this has proved to be one of the most valuable. Benbow (1995) stated that “bead stringing is the classic preschool activity for developing speed and dexterity in the alternate use of translation patterns” (p. 260).
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There are students for whom learning the motor plan for stringing objects is tremendously challenging, and they literally might spend many months practicing this task to master the ability to place just one large ring onto a 1⁄4-inch diameter rope. The stringing activity that is selected depends on the fine motor problem the therapist is trying to address. For example, some students do not yet have consistent object permanence, and if the objects they are stringing are so large that they cannot see the string emerge from the other side with just one thrust, they will be unable to imagine how to continue the activity. Activities (a), (b), (d), and (e) from the following list are best for these students. Other students have difficulty with the eye-hand coordination necessary to place the tip of the string into the object. Activities (a) and (c) are good starting activities for these students. Some students have such difficulty using two hands together that they benefit from stringing a series of eye bolts on a wooden shape, because the therapist can help stabilize the wooden shape with the eye bolts while the student concentrates on placing the string tip into the eye bolts. It is best for the student to also hold onto the wooden shape along with the therapist, as this enhances the development of bilateral coordination. Three main factors, therefore, should enter into the therapist’s decision about which stringing activity is best for a student: (a) the size of the hole in the object, (b) the length of the hard tip on the string, and (c) the stability of the object (e.g., is it fixed or does the child have to stabilize it in the hand). Following is a list of efficacious stringing and lacing activities, in an estimated order of difficulty from easiest to hardest: a. Placing 11⁄4-inch rings on a 1⁄4-inch diameter rope that has duct tape stabilizing the end of the rope. (Note: Oversized rings can be obtained either from a hardware store or manufacturers’ recyclables; they are not typically available in a toy store; see Figure 13-5). b. Placing 1⁄2-inch rings onto gimp (because the gimp stays stiff and a pincer grasp is not necessary). c. Stringing plastic frogs (Ideal Funtastic Frogs) designed with a small hole on one side and a large hole on the other side (holes range in size from 1⁄8 inch to 1⁄2 inch, depending on which of the three sizes of frogs are selected), with a cord that has a 2-inch long hard tip (the different size holes allow this activity to be graded at several different levels; see Figure 13-6). d. Small rubber shapes (Lauri “Beads and Baubles”) with a 3⁄16-inch hole and cord with a 1-inch hard tip (see Figure 13-7).
Figure 13-5 for lacing.
One-quarter–inch rope with 11⁄4-inch rings
Figure 13-6
Ideal Funtastic Frogs for lacing.
e. Inserting a 1-inch hard cord tip through a series of eye bolts arranged on a wooden shape (use pre-drilled wooden basket bottoms from a craft store and grade the activity based on the size of eye bolts placed into the holes; see Figure 13-8). f. Stringing small “pony” beads. g. Stringing large wooden beads. The challenge with large beads is that several thrusting motions of the skill fingers are necessary to move the string all the way through the bead, which is challenging for many students. Using the “thread the needle” motion to push a string through a large bead requires skilled intrinsic muscle movements. h. Once students have mastered placing individual objects onto strings, they then transition to per-
A Fine Motor Program for Preschoolers • 275
Figure 13-7 Baubles”)
Rubber shapes for lacing (Lauri “Beads &
Figure 13-9 upper left).
c.
d.
Figure 13-8
Eye bolts lacing activity.
forming tasks that involve more complex sequencing, such as lacing cards. 3. Finger isolation activities (individual finger skill, pincer grasp): a. Hopping ants: Use the plastic ants from the commercial game, Ants in Their Pants, and encourage students to use an index finger to make them jump. Once students have mastered the basic finger movement, therapists can set up a variety of items for the ants to jump over, or targets at which they can jump. b. Spinning tops: Therapists should provide a wide array of tops for spinning, with the easiest tops being those with a thick stem. Spinning tops helps students isolate the thumb and index finger, and also encourages a skilled finger motion (similar to the finger-snapping motion). A “stemless top” can be used for students who
e.
f.
Tops, including a stemless top (“optic top,”
do not yet have the dexterity or motor planning ability to use a top with a stem (see Figure 13-9; the top in the upper left of the picture is the stemless top). Geoboards: These are mentioned in the Strong Hands section of this chapter, but they also encourage isolated use of the thumb and index finger or, sometimes, just the index finger to stretch a rubber band down from a top point to a bottom one. As the designs become more complicated, this activity also helps develop fine motor planning ability. Eye droppers: Eye droppers can be used as a table top activity, at a water table in the classroom, or in the bathtub at home. Water can be mixed with food coloring to make “dribble pictures” by dripping the food coloring onto paper towels or coffee filters. (Note: young 3year-olds with fine motor delays usually have difficulty with the motor planning necessary for this activity, so it is more often used with the older preschoolers.) Tissue paper pictures: The therapist gives the children scraps of tissue paper, and asks them to roll each piece into a small ball by using only the skill fingers. The balls can be glued onto construction paper to form a picture. Sometimes the therapist can draw a general shape (e.g., a pumpkin outline) and the children can make enough tissue paper balls to fill up the outline. Coins and buttons: Children can play a variety of games with buttons and coins, including using the skill fingers to insert them into a bank, picking them up and arranging them as part of a counting or matching game, making designs with buttons on the table, sorting buttons according to size, and so on. Teachers in the
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preschool program often use button activities to reinforce academic concepts while challenging fine motor skills. To encourage the development of finger dexterity, the buttons or coins must be moved or turned over without bringing them to the edge of the table. Large containers of mixed buttons often are available at local fabric stores. 4. Puzzles (dexterity, fine motor planning, strength): It is beyond the scope of this chapter to discuss the visual perceptual aspects of puzzles, but in addition to developing part-to-whole skills and other kinds of visual matching (e.g., with formboard puzzles), puzzles can encourage the development of fine motor skills. Some students have such reduced dexterity that it is challenging for them to insert wooden pieces into a formboard, and they often incorrectly assume that because they cannot physically insert the piece, their initial impulse about where to place it must have been wrong. It is particularly concerning when students correctly surmise where to place a piece, but then assume that their visual assessment was wrong because they cannot insert the piece successfully. These students are provided with puzzles well within their range of ability from a visual perceptual aspect, and are helped to develop the physical strategies for inserting the pieces successfully. They work first with wooden puzzles, and then eventually work on inserting pieces to Lauri rubber puzzles, which often are more challenging in terms of both finger dexterity and fine motor planning. Puzzles with small pegs on top of each piece are helpful for developing thumb-index finger isolation. 5. Zoo Sticks (strength, motor planning, grasp): This plastic toy has an animal at the top, with two long tweezer tips extending from either side of the body. The child grasps the middle of the tweezers and squeezes to pick up small objects. The therapist scatters cotton balls across the table, and the animals “clean up the trash” by picking up the cotton balls and transferring them to a container placed in the middle of the table. (Cotton balls have proved to be the most successful material for preschoolers to pick up.) Students with less skilled hands tend to use a fisted grasp on the shaft of the tweezers, whereas more skilled students tend to use only their skill fingers (Figure 13-10). 6. Wind-up toys (grasp, strength): Wind-up toys are available in a variety of levels of resistance, as well as with a variety of different kinds of knobs. The larger the diameter of the knob, the easier it usually is for students to turn. Some wind-up toys come with a built-in key-shaped knob, which is typically the easiest kind to wind. Therapists should be familiar with the resistance levels of the various wind-up
Figure 13-10
Zoo sticks with cotton balls.
toys in their collection so they can provide the appropriate level of challenge for a given student. There is remarkable variety in the levels of resistance among the different wind-up toys available. Windup toys are particularly useful because the motor plan for the winding motion is important for functional tasks such as turning the volume knob on a radio, or closing a screw-top jar. 7. Stickers: This activity is good for students who are just learning to isolate the thumb and index finger to pull a sticker from the backing, before the OT session the therapists remove the background paper surrounding the stickers so that it is easier for the students to be able to determine the exact edge of the stickers to pull them off independently. Students begin with large-size stickers and transition to smaller stickers. Eventually they can separate stickers from the background paper with no difficulty. Therapists can use a variety of stickers, including the colorful circle stickers of various sizes (which do not have the background paper) available at office supply stores. 8. Buttoning (grasp patterns, motor planning): For therapists who have access to a sewing machine, a simple homemade button game can be created using interfacing sewn between two 4-inch square pieces of fabric. Half of the sewn squares have a buttonhole in the middle, and the other half have a button sewn onto them. The game can be graded in difficulty, based on the button size. Each set of two sewn squares should have two matching buttons associated with it; one button is sewn to the matching cloth square and the other button is loose. Children first practice putting the loose button through the hole and pulling it out the other side. Once they understand the concept of putting the button through the hole, they use the button that is sewn to the matching cloth square. At least some of the buttons and buttonholes should
A Fine Motor Program for Preschoolers • 277
Figure 13-12
Figure 13-11
The button game.
be large, so that there is room for the therapist’s fingers along with the child’s during the hand-overhand stage of teaching (Figure 13-11). Once children can button and unbutton all of the square sets in the button game, they are ready to button and unbutton a variety of old cardigan sweaters (with varying button sizes to grade the activity for difficulty) that are stored in the OT clinic for that purpose. It is surprising how motivating it is to students to button and unbutton a “grown-up” sweater. (Note: For practice with buttoning an adult size cardigan, the sweater is placed on the table, not worn by the student.) The sweaters also help students to understand sequencing buttons on a garment. Eventually, students work on buttoning and unbuttoning their own garments. 9. Bristle Blocks (strength, visual motor, motor planning): Although a wide variety of classroom-type manipulatives are available, Bristle Blocks are one of the most valuable because they are so versatile. They are initially used as part of a strength-building program, as they can be difficult for some students to join and separate. Once students have mastered the strength component of Bristle Blocks, they are then able to build in a variety of ways. These blocks provide more variety than Duplos, because they can be used in both horizontal and vertical orientations. They encourage the development of eye-hand coordination, and can also be used to encourage the development of representative building (e.g., students can make a table, bed, house), which in turn can facilitate many other areas of development (e.g., visually copying from a model, language, cooperative play). Although all of these activities encourage the development of the muscles needed for fine motor skills, the
Lateral pinch grasp.
therapist needs to attend to how each child performs them. A child with poor hand skill often finds a way to use the less-skilled lateral pinch grasp, even in the bestdesigned activity (Figure 13-12). For children with significant hyperextensibility in their joints, however, alternative grasp patterns may be necessary for them to perform an activity successfully. Because of their joint laxity, they often do not have a good physical foundation in their fingers to support skilled grasp patterns with small manipulatives. Children with hyperextensible fingers use the limits of their hyperextensible joints to create grasp patterns that provide them with the stability they need for motor tasks. By choosing these alternative grasp patterns, however, they sacrifice the ability to use fine, skilled movements because they are choosing stability over skill. Hyperextensible finger joints are not particularly unusual, but they sometimes require that adults working with a child help that child to be successful in fine motor tasks through a variety of adaptations. For example, the dexterity necessary in fine motor tasks perhaps should be reduced until the child is better able to sustain skilled grasp patterns with small objects. Also, the child may use an adapted pencil grasp (rather than the traditional “tripod grasp”) that provides both stability and skill at the same time. Benbow (1995) stated that “the functional use of the hand depends more on joint stability than joint mobility. Children adopt many ways to make their hands work for them when they lack joint stability” (p. 267).
The therapist must know the limits of the child’s hand skills well enough to know when to try to elicit a more traditional skilled grasp with manipulatives, and when to recognize that the child is using as skilled a grasp as is physically possible for that child. The preceding list of activities is meant to provide enough examples so therapists will be guided in their ongoing selection of a wide variety of therapeutic activities and toys. Parents, teachers, and children constantly contribute new activity ideas, and many of the traditional preschool activities (e.g., gluing pasta and
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beans to make collages) provide the same kinds of appropriate fine motor challenges as those listed in the preceding list of Smart Hands activities and manipulatives. When therapists consult with teachers, it is valuable to suggest new activities, but it is even more valuable to point out those activities and toys already available in the classroom that help children to develop good hand skills. One particularly helpful way to provide a workshop at a local nursery school is not only to bring toys from the OT clinic, but also to select toys from the school’s classrooms ahead of time so that their merits can be pointed out to teachers. Incorporating the school’s toys and materials into the workshop can regenerate teachers’ interest in toys that previously seemed humdrum.
FINE MOTOR PLANNING Many preschool students who receive OT services have a fine motor planning problem, which may or may not be accompanied by immaturities in fine motor skills. The students with more severe fine motor planning difficulties tend to have a diagnosis of Pervasive Developmental Disorder–Not Otherwise Specified (PDD-NOS), or Autism Spectrum Disorder, whereas the students with milder fine motor planning difficulties may have no formal diagnosis at all. For all students with motor planning difficulties, assistance in the form of hand-over-hand help, visual modeling, picture sequence directions, and verbal cues should be provided when unfamiliar fine motor tasks are presented. The assistance is faded as the student becomes more independent with the task, with hand-over-hand assistance being eliminated first. Once a student has mastered the use of a specific manipulative or toy, a similar manipulative or toy is introduced. This process is repeated over time, with occasional repeated presentation of the original manipulative or toy, so that the student develops improved ability to generalize among similar fine motor tasks. One reason that therapists provide such a large variety of activities within one activity domain (e.g., stringing tasks, wind-up toys, tops) is so that students
Roll the dough
Figure 13-13
Push the cookie cutter
with motor planning difficulties can sharpen their ability to apply motor plans from one fine motor task to a different one. For students with moderate to severe motor planning difficulties, coordinating matching materials between the classroom and OT clinic is particularly critical. The classroom staff is instructed in the physical or verbal cues that should be used with that student, and cues fade in all settings as the students make progress. Students with a milder level of fine motor planning difficulty are able to quickly make associations among similar tasks, and do not need the daily repetition of the exact same motor tasks because they are able to generalize much more easily from tasks performed in the OT sessions to materials available in the classroom. For students with fine motor planning difficulties, however, it is especially critical for the occupational therapist to be aware of the kinds of materials available in the students’ classrooms so that the OT activities will ultimately provide the students with the skills they should successfully and independently use with the fine motor materials at school. It is often difficult for students with moderate to severe motor planning difficulties to complete multistep art projects. Students in the self-contained class for autism spectrum disorders complete the same therapistplanned art project every single day for 1 week. The repetition over 1 week’s time significantly increases their independence by the end of the week. Because it is difficult for these students to make generalizations, even though the project is the same every day for a week, it seems new enough each day so that it is still interesting and challenging to them. They are able to recognize their improved independence as they complete the fifth and final version of the project. A typical art project for this class might include a page with three outlines of circles, accompanied by three circle-shaped pieces of construction paper in red, yellow, and green. The students must either follow a visual model, picture sequence directions, or verbal instructions to correctly glue the construction paper circles to create a picture of a stoplight on the paper. See Figure 13-13 for an example of step-by-step picture sequence directions for a play dough activity.
Take the extra away
Cookie on the pan
Step-by-step picture sequence directions for making play dough “cookies.”
A Fine Motor Program for Preschoolers • 279
SCISSORS When scissors are held correctly, and when they fit a child’s hand well, cutting activities exercise the same intrinsic muscles that are needed to manipulate a pencil in a mature tripod grasp. The correct scissors position is with the thumb and middle finger in the handles of the scissors, the index finger on the outside of the handle to stabilize, and fingers four and five curled into the palm. The lower handle of the scissors should rest on the distal joint of the middle finger, and the upper handle of the scissors should rest on the distal joint of the thumb (Figure 13-14). The tips of the scissors should be pointing away from the child, and the wrist of the cutting hand should be in extension (Benbow, 1995). When cutting, movements of the fingers should be in the intermediate range of excursion between very flexed and very extended to use the intrinsic muscles to their maximum benefit (Benbow, 1990a,b). Many children hold scissors with the thumb and index finger in the handles. This position does not allow for proper control of the scissors, and does not help develop the hand for fine motor skill. When scissors are held in this manner, the scissors movements are performed primarily by the larger muscles of the forearm rather than primarily by the intrinsics (Benbow, 1990a,b). Parents and teachers can make a tremendous difference in a child’s hand development simply by teaching the proper scissors grasp. It is necessary to check throughout the year to be sure children continue to use the correct grasp because in the early stages of learning the habit can be lost. The best scissors for children have sharp blades, blunt tips, and small-holed handles. In recent years the trend for children’s scissors has been for the handles to be formed in such a way that they actually discourage the use of the correct scissors grasp. Rather than have children use scissors in their skill fingers, the design of these scissors encourages children to place all four fingers in the handles and keep their index finger on the inside of the lower handle (Figure 13-15). The near-
Figure 13-14
Correct scissors grasp.
Figure 13-15 Incorrect scissors grasp, encouraged by a less than desirable scissors design.
ubiquitous use of this style of children’s scissors can make it difficult for therapists to reinforce the correct scissors grasp in their students. The Children’s Learning Scissors (available from several sources, see Appendix) and, in rare cases, the Craft Scissors (a larger version of the same scissors, used only for exceptionally large preschoolers) are used exclusively in the Newton Early Childhood Program for all preschoolers. The therapists recommend that community nursery school students who receive after-school OT services be provided with Children’s Learning Scissors for use at home. Because many community nursery schools order low-cost scissors in bulk from educational catalogues, it has been challenging to convince them to purchase the Children’s Learning Scissors, although some local schools do use them. Therapists see a significant difference in scissors skills between students who use the Children’s Learning Scissors with the correct grasp, and students who use commercial scissors similar to those pictured with an incorrect grasp. Cutting with scissors is an excellent fine motor activity, and scissors activities can be adapted to children of varying skill levels. Three and one-half years of age is the appropriate time for the majority of children to begin learning scissors skills, because before this age most children have not yet developed adequate separation of the two sides of the hand to be able to isolate their skill fingers adequately for skillful scissors use. Young 3-yearolds tend to flex and extend the ring and little fingers along with the other fingers while cutting, and do not inhibit this movement of the nonscissors fingers until 3.6 to 3.11 years of age (Schneck & Battaglia, 1992). Also, the hands of most early 3-year-old children are so small that even the tiniest scissors available have handle holes that are too large to allow for proper control with the correct grasp. When the handle holes are too large, children tend to place most or all of their fingers into the handles, thereby learning the incorrect finger position for skilled use of scissors. A hierarchy of scissors skills used for planning activities for preschoolers is listed in Box 13-3. Many
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BOX 13-3
Hierarchy of Scissors Skills Used for Planning Activities for Preschoolers
Grade the scissors activities in this order: 1. Snip narrow strips of paper, approximately 1/2-inch wide. Teaching goals: a. Learn to position scissors correctly on fingers. b. Learn the cue, “thumbs up” while cutting (to encourage a neutral forearm position, rather than pronation). The “confetti” cut by students can be saved in large, clear plastic jars. Students are motivated to cut several strips of paper at a time so they can add their paper to the growing pile in the jar. Another activity at this level of development might be to have the children “fringe” the edge of a piece of paper. 2. Cut on pre-drawn lines on narrow strips of paper (1/2-inch wide). Teaching goal: Learning to “aim” and direct the scissors when cutting. 3. Cut on pre-drawn lines on strips of paper 1 to 2 inches wide. Teaching goals: a. Students begin to develop repeated cutting skills; this means that they do not close the scissors all the way each time they cut, as they did in the previous two stages of scissors skills. b. Students learn to have the “helper hand” also be “thumbs up” (i.e. wrist position in neutral) while holding the paper for cutting at this stage. (If the hand holding the paper is pronated, the cutting hand tends to also pronate.) 4. Cut straight-line shapes such as squares and triangles. Teaching hints to provide to students: a. Cut off excess paper as you go along. b. Turn the paper, not the scissors. c. Do not tear the paper when using scissors. 5. Cut rounded shapes. Teaching hint: Keep the bulky side of the cutting project in the noncutting hand.
sized”) markers for drawing and writing. Crayola markers are the most widely used, because the stripe near the writing point provides an excellent visual cue to help children to remember where to place their fingers. The diameter of the writing implement and its effect on pencil grasp recently has been commented on in the literature (Burton & Dancisak, 2000; Windsor, 2000), but a final conclusion about what diameter is best has not yet been determined. However, it seems that it might be useful for therapists to be flexible about trying smaller-diameter implements in cases in which preschoolers are having significant difficulty developing a skilled grasp on large-diameter drawing implements. Therapists in the Newton Early Childhood Program rarely use crayons with the students who are receiving OT services. This is because markers offer little resistance to make a mark on paper, whereas crayons require significant pressure. Crayons provide an unnecessary challenge that makes it impossible for some students to develop a skilled grasp with drawing implements. In addition to large-diameter markers the therapists sometimes use large-diameter pencils, and paintbrushes of various handle thicknesses. To encourage students to hold close to the tip of the brush, the upper half of the paintbrush handle can be cut off before use. The normal sequence of development is that children initially use a static grasp on a drawing implement, and then progress to using a dynamic grasp (see tripod grasp in Figure 13-16), with the hand and forearm resting on the table. Because preschoolers are at a malleable stage of fine motor development, and because the preschoolers referred to the Newton Early Childhood Program are considered to be at-risk, the program therapists and teachers encourage children to use either a tripod or quadrupod grasp. The quadrupod grasp is similar to a tripod grasp, except that the ring finger also is on the shaft of the drawing implement. These open web space grasps also are used to perform
children can accomplish the first three levels by the age of 4, and then accomplish the last two levels between 4 and 5 years of age. (Note: Use card-weight or construction-paper weight for all levels. Once students have mastered cutting the heavier weight paper, they can cut regular-weight paper.)
DRAWING AND WRITING The preschoolers in the Newton Early Childhood Program are provided with large-diameter (“primary-
Figure 13-16
Tripod grasp.
A Fine Motor Program for Preschoolers • 281 common activities of daily living, such as buttoning small buttons. Individual variations in pencil grasp may occur as the children continue through later grades in school, but hopefully those variations contain these important components of the dynamic tripod grasp: the open web space, precision translation, and precise rotation of the fingers (Benbow, 1995). Not all students are able to consistently use one of these two commonly accepted skilled grasp patterns. Some children, particularly those with hyperextensible joints, do not ever achieve an “ideal” grasp with an open web space. The children who typically need to use a closed web space grasp are those who need additional stability, which in the long run is more important than mobility, as noted earlier in this chapter. The problem of thumb interphalangeal hyperextension is a specific example of a grasp frequently seen in preschoolers with hyperextensible fingers. When the thumb is hyperextended, it “fixes” the half-closed web space position (providing stability) so that intrinsic muscle movement is difficult to achieve (as seen earlier in Figure 13-2). Using large-diameter markers with the slant board surface encourages children to keep the thumb in flexion while drawing or writing to facilitate a fully opened web space posture. Regardless of the less-skilled grasp variations that are necessary to increase stability for some students, therapists try to ensure that every single student uses the skill fingers to hold and manipulate the drawing implement, and that they are able to achieve a dynamic grasp of some sort (with the drawing hand resting on the table) by the time they enter kindergarten. In other words, no student in the program “graduates” from OT services while using any of the “primitive grasps” discussed by Schneck and Henderson (1990), although a number of students enter kindergarten using a static rather than a dynamic grasp. The primitive grasps include those in which the implement is held in the fist like a hammer, the digital pronate grasp with only the index finger extended (Figure 13-17), and others. The integrated preschool classrooms are all provided with developmentally appropriate drawing materials such as large-diameter markers and slant board or vertical drawing surfaces. The students’ grasp patterns with drawing implements are monitored regularly by the teachers and therapists. If a child is approaching 4 years of age and is not yet showing the appropriate development of grasp patterns, direct guidance is incorporated into his or her educational program, as well as the OT program. To help children learn how to hold a drawing implement, they are asked to form a rounded circle (often referred to in this practice as a “lobster claw”) with their thumb and index finger. (Because the program is located in New England, most of the students
Figure 13-17 Digital pronate grasp, with only the index finger extended.
are familiar with lobsters.) The children are asked to have the lobster hold the stripe at the base of the Crayola marker, and all drawing or writing activities are carried out on a 20-degree slant board. Initially, children should be encouraged to begin a drawing with the skilled grasp pattern, but not be expected to use this grasp pattern for the entire drawing. Once they develop the habit of initiating drawings with the correct grasp, they typically develop the endurance to use the skilled grasp for longer periods each time until it eventually becomes their preferred grasp. Some children quickly develop the understanding of where to place their fingers, but may keep the shaft of the marker under their palm in a digital pronate grasp. With these children therapists might place a sticker at the top of the marker as a visual reminder: If the child cannot see the sticker they know that they need to reposition the marker in their fingers. When the child slips out of using the correct grasp, instead of saying, “You need to fix your fingers on the marker,” therapists can say, “Where’s the lobster?” This whimsical way of pointing out that the marker is not being held correctly seems to be palatable to children; instead of correcting a mistake they are “finding the lobster again.”
HAND PREFERENCE The strongly academic nature of the kindergarten curriculum in the surrounding community dictates that students are more comfortable and successful in kindergarten if they have developed adequate skill for drawing, writing, and scissors use for at least one hand. This means that it is useful to know which of a child’s hands is significantly more skilled. For most students,
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the preferred hand is clearly evident. For the rest of the students, preferred hand use is observed for a variety of tasks, including but not limited to the following: spinning tops, other one-handed manipulatives (not including wind-up toys), pretend motions (e.g., “Show me how you stir the soup,” “Show me how you brush your teeth”), and use of a drawing implement. Parents might be asked with which hand the child eats. Obtaining a family history also can be useful; left handedness may run in a family. Hand grasp strength testing is not useful for this purpose because many people show greater strength in their nonpreferred hand (Clerke & Clerke, 2001). Noting the hand preference for scissors is not always useful, because many left-handed people skillfully use scissors with the right hand. Because the turning motion for the knobs on wind-up toys is in a right-handed skilled direction, many left-handed children turn wind up toy knobs with the right hand. Because many toys and tools in the everyday environment are oriented toward right-handed people, left-handed people typically develop a much greater level of skill using the right hand than right-handed people do with the left hand. It is perfectly functional for students to seem “ambidextrous” for most manipulative activities, but it is strongly preferable that in the months before kindergarten, they develop a consistent hand preference for writing and drawing, and a consistent hand for scissors activities (not necessarily the same hand). This is acceptable, as long as they are consistent about the hand used for the specific type of task. Children are not encouraged to use one hand more than the other unless there is a significant and clear difference in ability between the two hands. Most 41⁄2year-old children are able to recognize that difference, and choose to use their more skilled hand on their own. If the preferred hand and eye do not match, the child might consistently use the preferred or more skilled hand for drawing, writing, and scissors activities, but lead with the nonpreferred hand (the one that corresponds to the preferred eye) for a variety of manipulative activities. (See also Chapter 9 for more information on handedness.)
based on the three seasons of the school year. These books are composed of reproducible activity pages that, in addition to developmentally sequenced tracing activities, also include simple drawing activities, mazes, easy dot-to-dot pictures, and many other classroom activities related to the season. Because all of the pages include at least a few small pictures, these worksheets provide an excellent way to also work on coloring skills. 2. S.O.S.: This version of S.O.S. is similar to the original version, except that initials are not used in the squares. The child and therapist each choose a differently colored marker, and one person starts the game by drawing a vertical or horizontal line between two adjacent dots. The next person draws a line between two dots, and the players keep taking turns drawing lines in an attempt to finish a square. The person who draws the fourth side of any square is allowed to make a dot inside that square, thereby marking it as his or hers. Once all the squares in a grid are completed, each person counts his or her dots and a winner is declared. This is an excellent prewriting game for teaching pencil control, starting and stopping ability (needed for printing letters), and encouraging top-to-bottom and leftto-right formation of writing strokes. It can also encourage top-to-bottom and left-to-right sequencing when the therapist or teacher helps the child organize his or her counting of the dots to determine the winner. Children can develop some strategy skills as they begin to learn how to plan their move so that their opponent’s next move will not finish a square. S.O.S. grids can vary widely in size, but a 16-dot grid seems to work best for most preschoolers (Figure 13-18). 3. Drawing: Many students have difficulty not only with the physical control of the pencil, but also with the visual organization of drawings. It is beyond the scope of this chapter to fully discuss visual perception and its relationship to making representative
ACTIVITIES TO H ELP DEVELOP PENCIL G RASP AND CONTROL 1. Tracing: The act of carefully tracing a line, or the outline of a drawing, often elicits a more skilled grasp than the act of coloring the drawing. Children are asked to perform a variety of tracing activities as a therapeutic activity to enhance the development of prewriting skills. One source for highly motivating preschool tracing sheets can be found in the Prewriting Curriculum Enrichment Series by Spitz (1999, 2000a,b), which is a series of three books
Figure 13-18 (Left) Blank S.O.S. grid. (Right) S.O.S. grid game in progress.
A Fine Motor Program for Preschoolers • 283 drawings, but a short summary of the learn-to-draw program is provided. In this author’s experience, interest in representative drawing typically begins by the age of 4 for girls, and between 41⁄2 and 5 years for boys. Once children have reached an appropriate age; have at least minimal control of a pencil; and can draw a vertical line, horizontal line, and circle, they can begin playing representative drawing games. These games follow a sequence of using basic shapes to organize drawings. Preschool children tend to see objects as being made up of one or more basic shapes, rather than seeing the outline (or contour) of the object (as older children tend to do) (Ziviani, 1995). Therefore instead of outlining the shape of a train they are drawing, children tend to draw a rectangle for the train car with circles underneath it for the wheels. The learnto-draw program begins with drawing circles, and children modify their circles to become a variety of different objects, such as a lollipop, pizza, or balloon. Once children are comfortable drawing circles, and then making them into representations of real objects, they are taught to draw squares and rectangles. They are first shown how to draw the two vertical lines, and then join them with two horizontal lines. The children next draw squares or rectangles and modify them to become something representative (e.g., a square with lines on it can become a gift with ribbon tied around it). They are soon able to combine circles with squares or rectangles to become trucks, trains, a radio with circular knobs, or a door with a doorknob. Eventually they learn to draw triangles, which come last because the ability to draw diagonal lines comes later in development than vertical and horizontal lines. The possibilities for combining the three basic shapes are endless. A typical house drawing includes all of the basic visual constructs, including a plus (to encourage crossing the midline) for the windowpanes. Children who are provided with practice at making the basic shapes, as well as guided opportunities to combine them into drawings, tend to develop the skills and self-confidence to subsequently create a variety of drawings on their own. 4. Writing: Most children are able to write the letters of their first name in capital letters, correctly sequenced from left to right, by the time they enter kindergarten. Many children begin learning to write their first name between 4 and 5 years of age, with girls often learning to write their name earlier. At the latest, all students in the Newton Early Childhood Program begin learning to write their first name by January of their final year of preschool.
Box 13-4 is a developmental hierarchy that therapists can follow when teaching students to write their name. Some students are able to start at
BOX 13-4
Developmental Hierarchy to Follow When Teaching Students to Write Their Name
1. For students with significantly decreased fine motor skill and control, as well as some visual disorganization, name stencils can be made using oak tag and an Exacto knife. The students can trace the letters error-free with the stencil until they can write their names independently. Another good strategy for early learners is to laminate a copy of their first name, and then have the students practice by using a marker to trace and erase multiple times over the laminated example. Even at this early stage one should teach students to use top-to-bottom and left-to-right strokes. 2. The adult can write the student’s name using dots for tracing and have the student trace over the dots. Being very consistent about having them form the letters the same (and correct) way every time helps these students avoid having to reinvent their letterwriting strategy every time they try to write their names. For children with a long name, have them learn the first few letters independently, and then add on more letters. If they insist on writing their entire name, have them do the first part independently and then provide dots to trace for the rest of the letters. For a student who is unable to visually understand tracing a series of dots, write the name in yellow marker and have the child trace over it. For students who are unable to remember the direction for the strokes, make a brightly colored dot with a different colored marker at the ends of each line to be traced (therapists often use green for “start,” and red for “stop”). 3. Once students can successfully trace their name in dots, encourage them to begin to write the letters independently. During this transition therapists and teachers provide an oak tag strip with a visual model of the name to copy. Large visual models with at least 1-inch high letters work best with preschoolers. For 4-year-olds who have a name that begins with a difficult letter such as “S” or “Z,” or letters with any diagonal lines, it usually works best to have them trace the fully written letter rather than just the dots, at least at first. Students can be encouraged to make a “rainbow letter,” which means that they trace the already written letter multiple times with several different colors of markers so they can get additional practice tracing a difficult letter. Eventually, the kinesthetic memory helps them to write the letter independently, even though those difficult letters may continue to be challenging for them (from a developmental aspect), depending on their current chronological age.
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Level 2, whereas others initially need the support of the suggestions in Level 1. If a student is unable to write his or her name independently by the end of the final preschool year, he or she can use one of the methods from Levels 1 or 2 from this list.
WHAT MAKES THERAPY EFFECTIVE? There are significant developmental differences between young preschoolers (3 to 4 years) and older preschoolers (41⁄2 to 5 years). Three-year-olds need activities that are so intrinsically enjoyable and motivating that they may not even be cognizant of how challenging the activities are. In the sessions with younger children, therapists might present eight or more activities within a 30-minute session, as students’ attention spans are shorter and they need a great deal of stimulation to continue working on tasks that are difficult for them. For most activities therapists try to find a level of challenge that is only a small increment above the students’ current level of performance, and always include one or two activities that are within their current level of performance so that the children can experience a feeling of mastery. The preschoolers rarely ask why they are attending the OT sessions, and simply refer to these sessions as “my afternoon school.” For students who are particularly savvy, and who initially question why they are participating, therapists encourage parents to say something like, “You mentioned that the projects at the art table at school are hard for you, and this [OT] is a class that will help you learn ways to make it easier and more fun for you.” All students, particularly those for whom the initial evaluation was somewhat stressful, typically demonstrate a tremendous sense of relief after the first treatment session. They quickly recognize that they will have a regular opportunity to participate in fine motor activities that are at the correct level of difficulty for them, which provides a huge boost to their confidence. Furthermore, most of the students are eager to learn the “tricks” that the therapists show them, and the community preschool teachers typically report that 1 to 2 months after beginning OT treatment, the students’ attitude and behavior begin to change significantly in the classroom. In particular, the students tend to demonstrate increased risk-taking at school by choosing manipulative activities they had previously avoided, and they also come willingly (and sometimes even spontaneously) to participate in classroom art projects. The willingness to try is the most important aspect of development that an occupational therapist can encourage. Once children begin expe-
riencing an appropriate level of fine motor challenge on a regular basis, their skill levels begin to improve and they often begin to bring in projects from school or from home to show the occupational therapist. Progress toward treatment goals is made, therefore, through an ongoing process that occurs throughout the week, not just during a therapy session. Most children have a desire to please adults, and many children in the early stages of treatment find it easier to cooperate with their therapist in the supportive clinic environment to perform challenging fine motor activities than with their parents or teachers. Therefore the occupational therapist is often the first person that can entice a child into attempting something difficult. The ability to grade activities and task analyze them helps occupational therapists to ensure successful experiences for students the first time they try a new activity. Occupational therapists have the ability to change the child’s attitude, which may be the most important contribution therapists can provide to help a child. The child should establish a good working relationship with the occupational therapist before activities are introduced at home. Therefore fine motor “homework” usually is not assigned in the initial months of therapy, and possibly not at all. Also, it is often difficult for parents to adopt a low-pressure, encouraging attitude, because of their close relationship with the child. Sometimes the parent–child “fit” does not comfortably allow for a continuation of the therapy work at home. Decisions about whether or not to provide home activities are made individually for each child, depending on the unique family features of each specific case; however, a few recommendations are typically made to all parents. In general, therapists ask parents to encourage their children to participate in naturally occurring fine motor activities at home, and they discourage home programs that place parents in the position of being a “second therapist.” This means that parents should make available an age-appropriate array of typical preschool manipulative materials. For the very young students, parents might be asked to put away the drawing and writing materials so that the child spends most of his or her time on manipulative activities. Parents also are discouraged from allowing their children to spend a great deal of time using a computer. Although many researchers and professionals who work with children do not recommend the use of a computer under 5 years of age (and for some the lower limit is 7 years) (Meltz, 1998, 1999), many parents seem to have difficulty setting limits on computer use with their preschoolers. Setting a time limit (e.g., no greater than a specified amount of time per day), and using a timer has been helpful for many families. Fine motor activities that children can participate in at home are listed in Box 13-5.
A Fine Motor Program for Preschoolers • 285 BOX 13-5
Fine Motor Activities That Children Can Participate in at Home
1. Cooking Activities: When making cookies, both strength and skill can be encouraged. Children can roll out small amounts of dough with their own small rolling pin, and cut cookies with cookie cutters. Sugar sprinkles should be placed in a small bowl so that the children have to pick them up with their fingertips to decorate the cookies. Children also can participate in tearing lettuce, pressing out pizza dough, pressing toothpicks into cheese squares, and other kinds of food preparation using their fingers. 2. Creating Wrapping Paper: Blank newsprint can be taped to the wall and children can decorate it with ink stamps, sponge painting, markers, or other materials. The paper then can be used to wrap gifts for family members or friends. Older preschoolers can learn to use table tape dispensers (which require fine motor skill and planning) to obtain tape for the package they are helping to wrap. 3. Spray Bottles: These can be used in the bathtub or sink at home, or to spray bushes and plants outside. Add a
Therapists try to help parents understand the importance of using manipulatives rather than writing utensils in promoting hand development. In particular, parents are encouraged to look at commercial toys in new ways. Many commercial toys “do it all” for the child, particularly some of the electronic games. Other toys, such as games with small parts, tiny blocks, and miniature doll dishes, require skilled finger positions and regulation of the intrinsic muscles that are needed for skilled grasp and placement. Parents are asked to evaluate their child’s toys and work toward a balance between the toys that require minimal skill and those that require more skill. Parents learn that although a toy requires the use of the hands, it may call for wrist and arm movements more than finger movements, and therefore may not further the development of fine motor skill. If parents wish, they are encouraged to bring a child’s toy to an OT session so that the therapist can use the toy with the child and provide feedback to the parent about whether or not the level of difficulty is
small amount of food coloring when spraying snow. Students usually begin by using two hands on the spray bottle, and as they grow stronger they are able to use it with just one hand. 4. Prewriting Activities: Parents are asked to provide Children’s Learning Scissors (see Appendix) for either the right or left hand, as needed, large diameter markers, paper, and a 20-degree slant board drawing or writing surface of some kind. Parents often purchase an additional pair of these scissors for the child to use at school. 5. Drawing and Writing Activities: Rather than have preschoolers sit down for “work time” at home, if a child chooses to draw at home, parents are asked to include the drawing with a letter to a friend or relative. If the child is learning to write his or her name, it can be written on the card or letter. That way, the functional use of drawing and writing is reinforced, and the child is less likely to feel that the parent is trying to act as a therapist or teacher.
appropriate for the child’s current developmental level. The ability to analyze the components of both therapeutic and day-to-day activities is one of the most important skills of the occupational therapist. Although it would be impractical to fully educate parents and teachers in this skill, it is possible to teach them to analyze fine motor activities well enough so that they are truly part of a team with the therapist. An involved parent can make important contributions to a child’s progress, because once parents understand the concepts behind fine motor development they are able to see activities in a different way. The parents and teachers feel empowered, and instead of feeling mystified or in awe of the therapist’s special activities, they become contributors in an ongoing process. This kind of partnership strengthens mutual respect and enhances the child’s progress. It cannot be overemphasized how important it is for everyone to understand the sequence of normal development, even if they are not taking an active part in providing the activities.
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CASE STUDY Tim became a student in an integrated preschool classroom at the Newton Early Childhood Program in the middle of winter, as he had just turned three years old and was eligible for services from the public schools. He had been given a diagnosis of PDD-NOS, with the primary referring concerns including immaturities in his language development, social skills, play skills, reduced eye contact, and apparent unresponsiveness when he was called by name. Before entering the program, Tim had been receiving services from Early Intervention, including physical therapy, OT, speech and language therapy, home visits, applied behavioral analysis, floor time, and a center-based toddler group. Specific difficulties noted by his two Early Intervention occupational therapists included heightened sensitivity to tactile inputs, avoidance of vestibular-based activities, overall low muscle tone, and immature fine motor skills. When Tim became a student in the integrated classroom, all of the preceding difficulties were noted, although he presented as a student with significantly reduced attention rather than as a student with PDD-NOS. The OT evaluation that was completed during Tim’s first few weeks of school indicated that although he had hyperextensibility in his fingers and reduced fine motor skill (both eye–hand coordination and grasp patterns), his most significant fine motor problem was his difficulty intuiting motor plans for using manipulatives. At that time Tim showed a preference for his right hand, but used both hands fairly interchangeably, which is not unusual for a 3-year-old. When picking up small objects, Tim tended to use a whole-hand pattern (raking) rather than the expected pincer grasp. He would even hold the tip of a lacing string in the palm of his hand rather than with his fingertips. Tim also showed immaturities with puzzles and copying designs, so it was recommended that visual perceptual skills also be included in his educational and treatment plan. Tim was referred for OT to address fine motor skills, visual perceptual skills, and sensory integration difficulties. The treatment notes from Tim’s first OT fine motor session indicate that the session was only 15 minutes long, which was the maximum length of time he was able to participate in structured tabletop tasks. Only five activities could be presented during that first session. Instead of using a top with a stem for twirling, Tim used a stemless top that simply required a brush of the hand to make it spin. He also used the Flying Fist toy (the child squeezes the base to make the top portion, the hand, pop off), at which point it became clear that his overall hand strength also was reduced for his age. His first stringing activity was placing the medium rings (1⁄2-inch) onto gimp, which was difficult for him. He did not spontaneously seem to understand that he should place his fingers close to the tip of the gimp; rather, he held far back on the gimp, which made it impossible for the tip to be inserted into the ring. (Like Tim, many young students need cues to hold close to the tip of the string.)
Two weeks later Tim could independently string the ⁄2-inch rings because he had learned the motor plan, but his eye–hand coordination was still poor. Six weeks later Tim was independently selecting his thumb and index finger to hold the tip of a lacing string, and also was occasionally placing his fingers at the tip of the string without reminders. Tim was, however, unable to use his skill fingers when a new activity, making small balls out of tissue paper, was introduced. Rather, he used his entire hand to make the small tissue balls. A few weeks later, the therapist introduced pop beads in the shape of vehicles, and Tim was unable to recognize the similarity between these pop beads and the “regular” Fisher-Price pop beads that he had played with at home. He needed full hand-over-hand assistance to be able to use the vehicle pop beads. He was, however, able at that point to string objects with a 1⁄8-inch hole, and his bilateral coordination for this kind of task was becoming smoother. A “spiral approach” for planning fine motor activities continued for the next year, with activities that had been mastered being replaced by similar but new ones, and as those were mastered the original activities were cycled back through the activities list to be sure Tim could still perform the original task that had helped him form the motor plan. Tim’s tolerance for tabletop work gradually increased so that after 3 months of OT he could work with the occupational therapist and one peer for 30 minutes, and his ability to work at tabletop tasks in the classroom gradually increased as well. Although his attention continued to be a problem, his increased levels of skill, interest, and selfconfidence helped him to be able to focus for longer periods of time in the classroom, where there were more distractions than in the quiet, nondistractible, OT treatment space. Tim developed more skill in all the areas of fine motor development, and he was retested at 4 years of age by the occupational therapist a year after his first evaluation upon entering the preschool program. During his first year in the program, his preferred hand seemed to have become less obvious. After initially appearing right-handed for a period of time, he now appeared to be strongly left-handed. Later, he began to again use his right hand more often. He showed a consistent preference, however, for his left eye, and his family had a strong history of left-handedness. Although both hands tested below age level for hand grasp strength, his right hand was significantly stronger than his left. Testing indicated that Tim had some visual perceptual skills that were within age limits, such as his puzzle skills and design copying skills with marker and paper (e.g., vertical line, horizontal line, circle). He continued to show immaturities in the area of hand grasp strength, however, and as scissors activities and drawing activities had been introduced by this time, immaturities with scissors skills and grasp and control of large diameter markers were seen. Tim’s finger hyperextensibility also contributed to his fine 1
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CASE STUDY—CONT’D motor immaturities. At that point his fine motor planning difficulties were considered to be mild, although still present. His ability to generalize motor plans among similar manipulatives had significantly improved over his first year of preschool. With the use of a 20-degree slant board surface, largediameter markers (no crayons), and gentle but consistent reminders about using the correct pencil grasp, Tim made the transition to using a static tripod grasp, and finally developed the beginnings of a mature tripod grasp as he began to rest his hand on the table more consistently. Two years after entering the program, at 5 years of age Tim finally established the consistent use of his right hand for drawing and scissors use. He would occasionally forget and place scissors in his left hand, but after starting to cut he would realize that the scissors were on the incorrect hand and switch them on his own. With markers, he was consistent about using his right hand. His ability to write his name gradually changed from being an arm and wrist skill with the letters filling up an entire page, to being a finger skill. By February of that year, he was able to sign his Valentines with the letters of his name only 1⁄2 inch high. Tim worked his way through the more difficult levels of the fine motor skills curriculum, including buttoning activities and multistep manipulatives. His hand grasp strength continued to test at the level of a child approximately 1 year younger than his chronological age of 5, although he was able to open and close all of the containers expected for a child his age, and could turn the knobs on even the most resistive of the wind-up toys used in the treatment sessions. Fine motor planning difficulties were rarely seen, and when they appeared Tim was able to learn a new motor task with only minimal verbal cueing, and no physical assistance. Interestingly, the primary area of difficulty for Tim during the last few months before he entered kindergarten was in the area of representative drawing. He had learned to draw recognizable, visually organized drawings of people,
but had not been able to create any other kinds of representative drawings on his own, particularly multiple component drawings. He had difficulty forming a visual plan for a drawing, although he could easily label all the components that might belong in the drawing (his verbal skills had reached age level by this time). He was able to draw a red circle on the paper for an apple, but was not able to make the drawing more complex by adding a stem or leaf, and certainly not an entire tree. After Tim was helped to learn how to draw basic shapes and incorporate them into gradually more complex drawings, he was able to make a small variety of multicomponent representative drawings by the end of the year (5 years, 4 months of age). Many students are able to learn these skills within the classroom setting, with the occupational therapist working naturalistically in the classroom, but in Tim’s case it was necessary to remove him to a separate, nondistractible room for the OT sessions for the second half of his last year of preschool. Two typically developing peers were brought along as models so the sessions would seem more like a regular school tabletop activity. By the end of the year, Tim had achieved nearly all of the objectives on the Newton Early Childhood “Fine Motor and Visual Perceptual Inventory for Children Entering Kindergarten,” (Broder, 2004) with the only significant area of weakness being that he still needed to improve his overall control of drawing implements. (The pre-kindergarten inventory can be found in Appendix 13 B.) His major areas of improvement over the 21⁄2 years that he received OT within an integrated preschool setting were in the establishment of a consistent hand preference for writing and cutting, improvements in fine motor planning, major improvements in fine motor skills including cutting, and good progress in pencil control, as well as visual motor activities such as representative drawing and design copying. It was recommended that Tim continue with OT services in kindergarten, primarily to address his continued needs with pencil control and representative drawing ability.
ACKNOWLEDGMENTS
REFERENCES
I am grateful to Cindy Broder, OTR/L, for her kind assistance with the editing of the initial draft of this chapter, and for her encouragement throughout this project, as well as for the past 19 years. I would also like to thank my husband, Richard Myers, for his enthusiastic support of this project and his expert help with proofreading.
Benbow M (1988). Loops and other groups, a kinesthetic writing system. Tucson, AZ, Therapy Skill Builders. Benbow M (1990a). A neurodevelopmental approach to teaching handwriting. Lecture notes from a workshop presented March 8, 1990. Benbow M (1990b): Personal communication, April 16, 1990. Benbow M (1995). Principles and practices of teaching handwriting. In A Henderson, C Pehoski, editors: Hand function in the child (pp. 255–281). St Louis, Mosby.
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Broder C (2004). Fine motor and visual perceptual inventory for children entering kindergarten, unpublished checklist. Burton A, Dancisak M (2000). Grip form and graphomotor control in preschool children. American Journal of Occupational Therapy, 54(1):9–17. Case-Smith J (1995). Clinical interpretation of “Development of in-hand manipulation and relationship with activities.” American Journal of Occupational Therapy, 49(8):772–774. Case-Smith J (2000). Effects of occupational therapy services on fine motor and functional performance in preschool children. American Journal of Occupational Therapy, 54(4):372–380. Case-Smith J, Pehoski C (1992). Development of hand skills in the child. Rockville, MD, The American Occupational Therapy Association. Clerke A, Clerke J (2001). A literature review of the effect of handedness on isometric grip strength differences of the left and right hands. American Journal of Occupational Therapy, 55(2):206–211. Hopkins H, Smith H (1978). Willard and Spackman’s occupational therapy, 5th ed. Philadelphia, Lippincott. Meltz B (1999). Beware this screen, too. The Boston Globe, p. F1, October 28.
Meltz B (1998). Computers, software can harm emotional, social development. The Boston Globe, p. F1, October 1. Schneck C, Battaglia C (1992). Developing scissors skills in young children. In J Case-Smith, C Pehoski, editors: Development of hand skills in the child (pp. 79–89). Rockville, MD, The American Occupational Therapy Association. Schneck C, Henderson A (1990). Descriptive analysis of the developmental progression of grip position for pencil and crayon control in nondysfunctional children. American Journal of Occupational Therapy, 44(10):893–900. Spitz P (1999). Autumn activities: Apples apples everywhere. Framingham, MA, Therapro. Spitz P (2000a). Spring activities: Flowers flowers everywhere. Framingham, MA, Therapro. Spitz P (2000b). Winter activities: Snowflakes snowflakes everywhere. Framingham, MA, Therapro. Windsor M (2000). Clinical interpretation of “grip form and graphomotor control in preschool children.” American Journal of Occupational Therapy, 54(1):18–19. Ziviani J (1995). The development of graphomotor skills. In A Henderson, C Pehoski, editors: Hand function in the child (pp. 184–193). St Louis, Mosby.
Appendix
VERTICAL AND SLANT BOARD SURFACES, AND A VARIETY OF FINE MOTOR MANIPULATIVES, INCLUDING CHILDREN’S LEARNING SCISSORS Therapro at www.theraproducts.com and OT Ideas at www.otideas.com are both excellent sources of fine motor materials. When a toy has been given a proper name in this chapter, it signifies that the toy is available under that specific name either on the website of one of these two companies, or from a supplier who can be located using that name with an internet search engine such as Google. At the time of this writing, all of the items mentioned in this chapter could be located through one of these two methods. The Spitz activity books (listed in the references) can be found on the www.theraproducts.com website.
FINGER PLAYS Finger Frolics, revised, by Cromwell, Hibner, and Faitel (Partner Press, available online at www.ghbooks.com) is a good source for finger plays on a variety of different themes. Some of the most useful finger plays from this
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book include “Wide Eyed Owl” (p. 60), “Here Is a Ball” (p. 91), “A Good House” and “Different Homes” (p. 19), “A Kitten” (p. 42), “Houses” and “Little Birds” (p. 31), “My Little Garden” and “My Garden” (p. 35), and “In the Apple Tree” (p. 22).
MEASURING HAND STRENGTH The Martin Vigorimeter, which is used in the Newton Early Childhood Program, is available from the following source: Albert Waeschle 11 Balena Close, Creekmoor Industrial Estate Poole, Dorset BH17 7DX United Kingdom Fax: 011 44 1202 650022 Telephone (includes numbers necessary to dial directly from the United States): 011 44 01202 601 177 Website: http://www.albertwaeschle.com Preschool norms for hand grasp strength obtained by using the Martin Vigorimeter can be found in this resource: Link L, Lukens S, Bush MA (1995). Spherical grip strength in children 3 to 6 years of age. American Journal of Occupational Therapy, 49(4):318–326.
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Appendix
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FINE MOTOR AND VISUAL PERCEPTUAL INVENTORY FOR CHILDREN ENTERING KINDERGARTEN Name of Child: _________________________________________________ Chronological Age: ____________________________
Date of Birth: ___________________
Date of Evaluation: ____________________________
Therapist: ______________________
______Skillfully uses a variety of multiple-step manipulatives (e.g., buttoning, wind-up toys, eye droppers). ______Laces using a skilled grasp. ______Builds a block tower of at least 10 one-inch blocks. ______Uses two hands together skillfully for bilateral activities. ______Demonstrates a clear right or left hand preference. ______Uses non-dominant hand appropriately as an assist (e.g., stabilizes paper while drawing). ______Holds primary-sized (large diameter) drawing implements with a skilled grasp. ______Draws and colors using skilled movement: forearm, wrist, fingers (most skilled). ______Draws or colors for five minutes with good endurance, pressure, speed, and accuracy. ______Draws a recognizable person with at least 8 body parts. ______Draws recognizable pictures with multiple components (e.g., a sun, tree, house). ______Copies horizontal and vertical lines, a plus, and a square. ______Copies right and left diagonal lines, and a triangle. ______Connects dots or completes simple mazes, and draws the lines with control. ______Prints letters of first name. ______Independently completes age-appropriate 5-10 piece interlocking puzzles. ______Positions preschool scissors on hand with skilled grasp, given one reminder. ______Cuts on a line smoothly and accurately, sustaining rhythm. ______Independently cuts out a square, triangle, and a circle shape, using appropriate strategies (e.g., turning paper so that scissors stay pointing away from body). 3 = Achieved
N = Needs further attention
Compiled by Cindy Broder, OTR/L, 2004 Newton Public Schools Early Childhood Program
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EVALUATION OF HANDWRITING Scott D. Tomchek • Colleen M. Schneck
CHAPTER OUTLINE PRE-EVALUATION DATA COLLECTION Writing Samples Interviews Record Review EVALUATION OF RELATED PERFORMANCE COMPONENTS Neuromuscular and Neurodevelopmental Status Visual Perception Motor Performance Formulation of Written Language Sensory Processing ACTUAL EVALUATION OF HANDWRITING PERFORMANCE Domains of Handwriting Legibility Components Writing Speed Ergonomic Factors Keyboarding Performance Commercially Available Assessment Tools SUMMARY
Writing is a way to record information and events; a tool for communication; and a means to project feelings, thoughts, and ideas (Chu, 1997). Occupational therapists are concerned with the occupational performance of individuals in play, work, and self-care activities. In childhood, a major occupation in the area of work is handwriting (Amundson, 1992, 1995; Chu, 1997). It is often one of the first tasks taught to students. Writing within learning tasks continues throughout the academic careers of children and is used to take
written tests, compose stories, take notes in class, copy numbers for math computations, and communicate with friends and family. Writing continues to be used throughout their lives in the home and work place to write checks, take messages, and communicate with others. Learning to write legibly is a complex task of childhood and therefore it is not uncommon for problems to arise during this learning process. Children may have illegible script, difficulties with letter formulation, lack the automaticity of writing, and therefore be unable to keep pace with their peers. As a result, school consequences of handwriting difficulties may be noted (Amundson, 2001) and may include the following. • A child may be assigned poorer marks for papers with poorer legibility but not poorer content (Chase, 1986; Sweedler-Brown, 1992). • A child’s slow handwriting speed may limit composition fluency and quality (Graham et al., 1997). • A child may take a longer time to complete writing tasks than peers (Graham, 1992). • A child may avoid handwriting tasks because it requires so much effort to produce text (Berninger, Mizokawa, & Bragg, 1991). When handwriting impairments that affect academic performance are noted, children are often referred to occupational therapists for evaluation and intervention (Bonney, 1992; Case-Smith, 1996; McHale & Cermak, 1992; Reisman, 1991; Tseng & Cermak, 1993). The occupational therapist is responsible for identifying underlying motor, sensory, cognitive, or psychosocial deficits that may interfere with the development of legible handwriting (Amundson & Weil, 1996). The process of evaluation is multifaceted with many interrelated components. The purpose of this chapter is to discuss the process of evaluation for handwriting impairments and is grouped into three main components: (a) pre-evaluation data collection, (b) evaluation of related performance components that may be interfering with handwriting, and (c) evaluation of the actual process of handwriting.
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PRE-EVALUATION DATA COLLECTION
Upon referral for handwriting problems, work samples often are offered to substantiate the need for referral. These samples should represent typical handwriting performance of the child (not the worst examples) and be analyzed to determine the types and magnitude of the handwriting difficulties seen in the classroom (Amundson, 2001). Comparing these samples to those of peers also may be of benefit in determining the magnitude of the difficulties, as well as gaining an understanding of teacher expectations. Informal evaluation of the work samples for alignment, size, letter formation, legibility, and slant may indicate need for further evaluation.
components could be used to predict scores in handwriting performance. This information can guide therapists in their evaluation of children based on teacher report of poor handwriting. Two factors that teachers indicated most frequently as important for handwriting to be acceptable were correct letter formation, and directionality and proper spacing (Hammerschmidt & Sudsawad, 2004). The most important criteria that teachers used to determine whether or not a student was having handwriting difficulties was their not being able to read the student’s writing. The majority of teachers answered that the methods they used to evaluate their students’ handwriting was comparing student handwriting to classroom peers (37%), followed by comparing student handwriting to models in a book (35%). This awareness can help structure the content of the occupational therapy evaluation and ensure that occupational therapy assessments produce results that are relevant to the children’s handwriting function in the classroom. The parents can provide insight on many of these same factors as the child accomplishes handwriting in the home. In addition, the parents can provide information unknown to the teacher such as the attitudes and interests of the child. This difference in perspective may be useful in identifying the causes of handwriting difficulties.
I NTERVIEWS
RECORD REVIEW
Teachers and parents likely have valuable information about the child that contributes to the assessment process. Teachers can provide information about the child’s unique academic strengths and weaknesses in the classroom, as well as the specific curriculum of the class. In addition, the teacher can describe the type of script used (i.e., manuscript or cursive), the style of script used (i.e., D’Nealian, Zaner-Bloser) and his or her general expectations of the students for handwriting. Specific to the child referred for assessment, the teacher can provide information on the place where the child accomplishes writing, when difficulties occur, what remediation techniques if any have been attempted, and his or her feelings on why the handwriting difficulties may be occurring. In addition, he or she can provide insight on the child’s history of handwriting instruction. Cornhill and Case-Smith (1996) found that students with poor handwriting, as identified by teacher report, scored significantly lower on three assessments of sensorimotor performance components (eye-hand coordination, visual motor integration, and in-hand manipulation) than students with good handwriting. The authors also found that scores on assessments of these performance
Reviewing the child’s educational file can provide information on past academic performance and any special services that may have been provided to the student. Information obtained from the educational file may reveal a pattern of educational difficulty or isolated findings that may be useful in the assessment of handwriting difficulties. This review of information also may require further interview of the teacher. Through classroom observations, examination of work samples, interviews, and record review a therapist is able to identify related performance components and administer assessments designed to determine whether deficits in the identified components exist and to what extent (Admundson & Weil, 1996).
Although discussed as separate assessment components by several authors (Amundson, 1992, 2001; Amundson & Weil, 1996), analysis of writing samples, interviews, and record review comprise the pre-evaluation data collection. Analysis of this information guides the necessary components and sequence of evaluation methods.
WRITING SAMPLES
EVALUATION OF RELATED PERFORMANCE COMPONENTS To assist in the process of identifying the cause(s) of the handwriting impairments in a student, analysis of the underlying performance components related to handwriting require evaluation. Here, underlying sta-
Evaluation of Handwriting • 293 bility, perceptual, sensorimotor, and written language functions are assessed to determine their impact on handwriting performance.
N EUROMUSCULAR AND N EURODEVELOPMENTAL STATUS A comprehensive neuromuscular assessment often initiates the physical evaluation. Active and passive range of motion limitations are noted and if present, may limit in-hand or upper extremity mobility necessary for handwriting. Muscle tone in the trunk and extremities (both proximally and distally) also is evaluated. Strength often is assessed through structured observation of antigravity postures and movements. Specific muscle testing may be necessary in the hands and upper extremities. To supplement neuromuscular findings, a neurodevelopmental assessment may be conducted. The neurodevelopmental assessment should include two groups of automated responses as markers for motor dysfunction. The first group of automated responses to be evaluated is the primitive reflexes. These reflexes appear during the late gestational period, are present at birth, and normally are suppressed by higher cortical function by approximately 6 months. Delayed integration of these reflexes has an impact on dissociated head and extremity movements and thus affects motor performance. For example, delayed integration of the asymmetric tonic neck reflex may limit dissociated head and upper extremity movement to the point of affecting development of hand dominance and midline crossing of the upper extremities. After evaluation of the primitive reflexes, the second group of automated responses to be evaluated is the postural reactions. Righting, equilibrium, and protective reactions must be evaluated. The coordination of these reactions into functional balance often is observed during free play and independent movements. Decreased functional balance in sitting may limit independent arm movement from trunk movement for writing. The child then moves the trunk with the arm for writing or frequently re-positions the paper as arm movement is needed. Together, the tone, strength, reflex integration, and balance development of a child serve as the foundation for the development of stability and stable movement patterns. If a child is posturally unstable she or he will likely use compensatory movement patterns, which in turn may affect motor control during handwriting tasks. For example, a child who exhibits instability in the upper trunk and shoulder may use a mid-guard posture or stabilize at the shoulder to stabilize his or her upper thoracic and cervical areas during handwriting. By doing so, the child’s fluidity and speed of
movement will likely be compromised. In addition, the child may fatigue quickly during handwriting tasks. These neuromuscular and neurodevelopmental skills serve as the foundation from which skilled mobility and motor skill are built. Deficits identified in these areas likely have an impact on performance of motor skill.
VISUAL PERCEPTION Visual perception is the ability to use visual information to recognize, recall, discriminate, and make meaning out of what we see. Visual perceptual areas include the visual receptive (acuity, convergence, tracking) and the visual cognitive, which include visual discrimination, visual memory, visual form constancy, visual spatial relation, visual sequential memory, visual figure ground, and visual closure. Together, these perceptual skills provide vital information that is used and relied on by many other systems for optimal functioning. For instance, when copying text from a blackboard, we use visual figure ground to select the appropriate text on the blackboard to copy, visual discrimination to differentiate among letters, and visual memory and sequential memory to recall the text to be copied; therefore it is important to distinguish visual perceptual problems from motor problems. Visual-perceptual skills, including visual-spatial retrieval and left-right orientation, enable children to distinguish visually among graphic forms and judge their correctness (Solvik, 1975; Thomassen & Teulings, 1983). Tseng and Murray (1994) reported that the 143 children in their sample of children with illegible handwriting had low scores on perceptual-motor measures. Tseng and Chow (2002) found a significant difference between slow and normal handwriters in upper-limb coordination, visual memory, spatial relation, form constancy, visual sequential memory, figureground, visual motor integration, and sustained attention. Clinical observations can be used to obtain some informal information of perceptual abilities in children who cannot participate in formal testing. Situations can be devised to assess specific areas or a child’s work can be evaluated. For instance, having a child find a certain toy in a toy box can assess visual figure ground. Asking a child to find or select an item he or she was shown could be used to assess visual memory. Spatial relation difficulties often can be seen when asking a child to accomplish writing tasks, because drawings, letters, or words may be rotated. In addition, alignment and spacing may be a problem. Visual discrimination difficulties may affect the child’s handwriting in several ways and can be evaluated through observation of the child during handwriting.
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For example, the child with poor form constancy may not recognize errors in his or her own handwriting and therefore not make corrections to errors. In addition, the child may be unable to recognize letters or words in different prints and therefore may have difficulty in copying from a different type of print or handwriting. The child also may show poor recognition of letters or numbers of different sizes or in different environments. If the child is unable to discriminate a letter, he or she may show poor letter formation in handwriting. Children with problems in visual attention may have difficulty with the correct letter formation and can be evaluated through observation of the child during handwriting activities. Children with attention problems may exhibit difficulty with spelling, mechanics of grammar, punctuation, capitalization, and the formulation of a sequential flow of ideas necessary for written communication. For the child to write spontaneously, he or she must be able to revisualize letters and words without visual cues. Therefore if the child has visual memory problems, he or she may have difficulty recalling the shape and formation of letters and numbers (Schneck, 2001). Other problems that may be seen when a child has visual memory problems include missing small and capital letters within a sentence, the same letter may be written in different ways on the same page, and the inability to print the alphabet from memory. The child’s legibility may be poor, and he or she may need a model to write. A child with visual spatial problems may show reversal of letters such as the m, w, b, d, s, e, and z and of the numbers 2, 3, 5, 6, 7, and 9. Children with difficulty with discrimination of left from right may have difficulty with the left-to-right progression or writing words and sentences (Schneck, 2001). In addition, the child may demonstrate over-spacing or underspacing and have trouble keeping within the margins. He or she may show inconsistency in letter size and may have difficulty with the placement of letters on a line, or the ability to adapt letter sizes to the space provided on the paper or worksheet. Careful observation and informal assessment can help to uncover problems contributing to poor handwriting. The formalized assessment of visual perceptual abilities usually is reserved for children of school age and older who have higher receptive language abilities, and are able to comprehend the verbal instructions inherent in these tests. Without receptive language abilities near the 5-year level, testing will likely be invalid because the instructions may be too abstract or not comprehended. To maximize performance and obtain the most accurate assessment of the individual perceptual areas, adaptation or simplification of verbal instructions may be necessary. For instance, when giving directions for the visual spatial relations areas, instead of instructing
the child to “find the form that is going a different way” or “find the form that is not the same as the others,” the child will likely better understand the more simple terms of “wrong” or “different.” Therefore a request to find which one is wrong may produce improved performance. Because we are assessing perception and not receptive language abilities or vocabulary, making these adaptations allows evaluation of the focus area, visual perception. Tsurumi and Todd (1998) have applied task analysis to the nonmotor tests of visual perception. This information greatly assists the therapist in analyzing the results of these tests. Care in interpreting and reporting test results should be taken because it is not always clear what visual perceptual tests are measuring. Refer to Table 14-1 for a listing of standardized assessments that may be used to assess these visual perceptual areas. For valid test results it is important to follow the standard instructions on standardized tests. If the standard procedures are not followed it should be stated when reporting the results. These visual-perceptual assessments assess nonmotor perception, in that they do not require motor coordination for the completion of testing. Instead, the child can select his or her choice among the options by saying the appropriate letter that corresponds to his or her selection. Most children, however, point to their response. Deficits in these perceptual abilities may affect many areas of development, especially fine and visual motor development. The information taken in visually guides our ability to reach to an object and the act of grasping that object. During writing tasks, visual information is used for spacing, alignment, and formation of all drawings and letters. When deficits in these areas, or in any areas that rely heavily on visual input for coordination, are detected, visual perceptual differences should be identified through formal or informal testing.
MOTOR PERFORMANCE For the purpose of this section, assessment of motor function is divided into the three broad areas of gross, fine, and visual motor development. There is much overlap between these areas of motor performance, in that common performance components (i.e., muscle tone, strength, coordination, visual motor integration) serve as the foundation for skilled motor output. There is also significant reliance between these motor skill areas. For example, stability aspects of gross motor development are vital in fine motor performance because stability provides a solid foundation from which skilled upper extremity usage is achieved. Both formal and structured observation assessment is described here. Some formalized assessments used to assess gross, fine,
Evaluation of Handwriting • 295
Table 14-1
Instruments to assess visual perception
Instrument
Author, Year
Ages
Areas Assessed
Developmental Test of Visual Perception, Second Edition (DVPT-2)
Hammill, Pearson, and Voress, 1993
4–9 years
Eye-hand coordination Spatial relations Figure ground Visual-motor speed Copying Position in space Visual closure Form constancy
Motor-Free Visual Perception Test-Third Edition (MVPT-3)
Colarusso and Hammill, 2003
4–11 years
Visual discrimination Visual memory Visual spatial relations Visual figure ground Visual closure
Test of Visual Perceptual Skills-Revised (TVPS-R)
Gardner, 1995
4–12.11 years
Visual Visual Visual Visual Visual Visual Visual
Test of Visual Perceptual Skills Upper Limits (TVPS-UL)
Gardner, 1997
12–18 years
Visual discrimination Visual memory Visual form constancy Visual spatial relation Visual sequential memory Visual figure ground Visual closure
and visual motor development are identified in Table 14-2. When evaluating any component of motor performance, not only are developmental milestones noted, but also special attention is directed to the qualitative dimensions of the motor skill. Developmental milestones provide evidence of what the child can and cannot do relative to children of a comparable age. A major goal of the assessment should be to determine the source of an observed and documented deficiency, that is, why the skill is problematic. Observations made about the qualitative aspects of motor control often pinpoint the area(s) of dysfunction and serve as the foundation for intervention planning. In addition to the value of direct observation of motor skill, observation of contextual aspects of motor skill also enhances understanding of the source of developmental delays.
discrimination memory form constancy spatial relation sequential memory figure ground closure
Gross Motor Skill Gross motor development refers to movements that require the use of large muscle groups. Ambulating, running, jumping, climbing, and ball play are all considered gross motor skills. In neurodevelopmental theory, the mobility necessary for these locomotor skills is superimposed on stability. Consequently, the ability to perform these skills, and the quality with which they are performed, is dependant on the condition of the child’s neuromuscular and neurodevelopmental status. Often, the neuromuscular status assessment is considered one component of the child’s gross motor status. Accordingly, gross motor includes both evaluation of developmental milestones and observations about the quality of the child’s movement patterns. Balance and stability are measured and observed as the child performs a number of motor tasks. These observations of
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Table 14-2
Standardized instruments used to assess gross, fine, and visual-motor skill
Instrument
Author, Year
Ages
Areas Assessed
Peabody Developmental Motor Scales-Second Edition (PDMS-2)
Folio and Fewell, 2000
Birth–83 months
Toddler Infant Motor Evaluation (TIME)
Miller and Roid, 1994
Birth–47 months
Bruininks-Oseretsky Test of Motor Proficiency
Bruininks, 1978
4.5–14.5 years
Test of Gross Motor Development, Second Edition (TGMD-2) Test of Visual-Motor Skills-Revised (TVMS-R) Test of Visual Motor Skills-Revised-Upper Limits Developmental Test of Visual Motor Integration (VMI)
Ulrich, 2000
3–10 years
Gross motor: Reflexes Stationary Locomotor Object manipulation Fine motor: Grasping Visual-motor integration Mobility Motor organization Stability Functional performance Social/emotional abilities Gross motor: Running speed and agility Balance Bilateral coordination Strength Upper-limb coordination Fine motor: Response speed Visual-motor control Upper-limb speed and dexterity Locomotor Object control
Gardner, 1995
3–13.11 years
Gardner, 1992
12–40 years
Beery and Buktenica, 1997
2–15 years
balance also have application to the vestibular processing of a child, illustrating the link between sensory and motor responses. Assessment of these gross motor areas often is done within the context of play-based assessment or strictly through observation. Having a child go through a simple obstacle course, for instance, can provide a wealth of information about balance, strength, and postural control. Further, within many clinic settings or natural environments a child has the opportunity to explore his or her environment. In doing so, the child likely ambulates, runs, jumps, or has to climb steps. Situations also can be developed to observe catch and throw abilities. Report of functioning during higher-level bilateral motor tasks such as riding a bike and swimming likely may be obtained from the
Visual motor control for design copying items Visual motor control for design copying items Visual motor control for design copying items
caregiver. As can be seen, throughout the evaluation, both developmental milestones are assessed and the quality with which they are accomplished is observed and analyzed. Deficits in stability noted during gross motor performance, especially trunk, shoulder, and neck, may or may not be present when a child is seated at a table to participate in handwriting tasks.
Fine Motor Skill Fine motor development refers to movements that require precise or fine motor actions and small muscles and more sensory feedback. Grasp of objects, writing, cutting tasks, and dexterity while accomplishing clothing fasteners are all considered fine motor tasks. When assessing fine motor skill it is again important to note the impact of stability and postural awareness.
Evaluation of Handwriting • 297 Stable positioning during fine and visual motor tasks enhances optimal performance, whereas instability diminishes fine coordination The importance of addressing biomechanical factors, such as weak intrinsic muscles of the hand, has been stressed (Peterson & Nelson, 2003). Fine motor skills are essential because accurately formed letters can be produced only by the proper timing and force control of coordinated arm, hand, and finger movements (Alston & Taylor, 1987; Thomassen & Tuelings, 1983). Children with illegible handwriting scored lower on fine motor measures than children with good handwriting (Tseng & Murray, 1994). Berninger and Rutberg (1992) examined additional variables and found that a fine motor task (sequentially touching the thumb to the tip of each finger) had the strongest correlation with handwriting. Levine, Oberklaid, and Meltzer (1981) not only found that 72% of 26 children with “developmental output failure” had difficulty with fine motor tasks, they further postulated that these children’s uncoordinated finger movements and diminished pencil control accounted for their slow, illegible handwriting. Researchers have reported two general types of grip assessment systems: component and whole configuration. In component systems separate components of the grip are evaluated (i.e., the position of each finger and the thumb, the relative position of the grip along the length of the implement, or the forearm position relative to the table). In whole configuration systems, all of the components of an observed grip are described together. The grip is considered as a discrete behavior and is labeled. Burton and Dancisak (2000) have suggested that the use of Schneck and Henderson’s (1990) 10-grip scale be used only for documenting the grips of individual persons and changes in their grips. If comparisons between persons are desired, then the authors recommended Schneck’s (1991) five-level scale be used. Tseng (1998) added three interdigital grasps to this five-level scale in the primitive grasp category and included the quadruped grasp as another mature grasp for a total of 14 grasp patterns. The task should be considered in the evaluation process. For example, in a coloring task younger children used a more mature grip to color the edge and then colored the center with a less mature grip. Older children slow down to color the edge and then continue with the same grip for the center of the object (Schneck, 1991). Many children used less mature grips when coloring spaces than when drawing. The most common grip used for coloring was the static tripod grasp, whereas for drawing it was the dynamic tripod grasp (Schneck, 1991). Berninger and Rutberg (1992) contended that finger function is the best predictor of
handwriting dysfunction, in which fine motor skill accounted for 52.5% of the variance in handwriting speed. Solvik and Arntzen (1991) found that poor coordination in the form of poor dissociation (exaggerated wrist and thumb movement) was inversely correlated with writing speed. In-hand manipulation can be assessed with translation and rotation tasks with the five small pegs and pegboard from the Nine-Hole Peg test. Administration and scoring procedures can be found in Case-Smith (1996, 1998). As in most assessments, initially the foundation skills of an area are assessed. Many of these areas relating to fine motor task performance are assessed though observation. Table 14-3 outlines the pertinent areas and specific questions that guide these structured observations in fine motor evaluation of handwriting. In conjunction with these observations, the attention of the evaluator can turn to evaluating the functional application of these foundation skills. Here, the child is asked to engage in purposeful tasks as a means of identifying strengths, weaknesses, and developmental levels. If the child is unable to perform a motor task, it is important to try to ascertain why, because an inability to perform a motor task may stem from one or several limitations including lack of strength, deficient muscle control, dyspraxia, cognitive limitations, or motivation. Determining the reason for dysfunction allows for observation of hand dominance and appropriate intervention planning.
Visual Motor Control There is much overlap between fine and visual motor skill, and often they are considered one entity. Visual motor control refers to the ability to coordinate visual information with motor output for visually guided movements. Appropriate visual motor control is predicated on intact visual localization and tracking abilities. Visual motor control is used to string beads, cut on a line, catch a ball, print within lines, and stay in the lines when coloring a picture. Some individuals may demonstrate better abilities for design copying items in tests of visual motor integration, but have difficulty when relating these abilities to handwriting. Therefore it is important to assess each area separately (see handwriting assessment section that follows). Fundamental to assessment is the recurrent theme of pinpointing the location of the breakdown in task performance. In the visual motor area, skills are dependent on adequate attention, visual perception, motor control, and motivation. A number of researchers have documented a significant relationship between visual motor skills and handwriting performance (Cornhill & Case-Smith, 1996;
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Table 14-3
Structured observations of fine-motor foundation skills
Foundation Area
Specific Observations
Hand dominance
Does the child demonstrate use of a dominant hand, mixed dominance, or no dominance at all? If the child has mixed or no dominance, does he or she avoid crossing the midline?
Grasp and prehension patterns
Can the child isolate finger motions for prehension of smaller objects? What grasp pattern does the child use to hold a pencil? Does the child use this grasp statically or dynamically? Does the child hold the pencil firmly? Does the quality of the child’s grasp and prehension abilities differ when they are just manipulating an object in comparison to when they are manipulating a tool for use (i.e., hammer, pencil, ball)? Does the child have adequate hand strength to hold onto objects?
Manipulation skill
What is the quality of the child’s in-hand manipulation skill? Can the child transition objects in his or her hand using transverse palmar (palmto-finger and finger-to-palm) motions, or does he or she stabilize the object and regrasp?
Precision of interactions with objects
Are tremors present? Do the child’s movements appear ataxic? Does the child use too much pressure when holding objects? Does the child use too much pressure to paper when writing? Does the child have a hard time damping their reach?
Task position and position of the child
Does the child frequently shift his or her position while interacting with an object? Does the child frequently turn or reposition a task? If so, is he or she doing so to avoid midline crossing or for visual inspection?
Ergonomic factors
What type of pencil does the child use? What type of paper does the child write on? Where is the paper positioned in relation to the child?
Daly, Kelley, & Krauss, 2003; Maeland, 1992; Tseng & Cermak, 1993; Tseng & Murray, 1994; Weil & Amundson, 1994). The Test of Visual Motor Integration (VMI) has been supported in the literature as a useful screening tool for handwriting abilities. Research suggests that students are ready to engage in formal handwriting instruction once they have mastered the ability to copy the first nine forms on the VMI (Beery & Butkenica, 1997; Daly, Kelley, & Krauss, 2003; Weil & Amundson, 1994). The researchers have concluded that most children who are typically developing will be ready for standard handwriting instruction in the later part of their kindergarten year. Visual motor integration was found to be the best predictor of legibility for both American and Norwegian children (Solvik, 1995) and a group of Chinese school-aged children (Tseng & Murray, 1994).
As can be seen by this discussion of assessment of motor performance, much overlap and interdependence exist between the areas of motor development. The ultimate goal of the process of motor assessment is to identify the unique strengths and weaknesses of the individual. Both formal and informal assessments determine this vital information. Once skill levels are identified, determining the etiology or source of the documented skill deficiencies provides the basis for program and intervention planning.
FORMULATION OF WRITTEN LANGUAGE A written language assessment may be indicated during a comprehensive assessment of handwriting, and especially when speed difficulties are noted. Here, the goal is to determine if problems in written language (i.e.,
Evaluation of Handwriting • 299 formulation) exist and if so, if they could be a factor affecting handwriting rate. It stands to reason that a child who spends more time in formulation of thoughts and written communication will also likely take longer to put those thoughts to paper. Written language assessment usually is accomplished by a speech language pathologist. Possible tools that may be used to conduct a written language assessment are summarized in Table 14-4.
Table 14-4
SENSORY PROCESSING Sensory processing is a broad term that refers to the way in which the central and peripheral nervous systems manage incoming sensory information from the senses (Lane, Miller, & Hanft, 2000). Basically, sensory processing refers to the sequence of events that occurs as we take in and respond to environmental stimulation. In the assessment of handwriting—in addi-
Instruments to formally assess written language
Instrument
Author, Year
Ages
Areas Assessed
Oral and Written Language Scales (OWLS)
Carrow-Woolfolk, 1995
3–21.11 years
Use of conventions Use of linguistic forms Communicate meaningfully
Test of Early Written Language (TEWL-2) Test of Written Language 3 (TOWL-3)
Hresko, Herron, and Peak, 1996 Hammil and Larsen, 1996
4–10 years
Basic writing Contextual writing Spontaneous formats Contextual conventions Contextual language Story construction Contrived formats Style Spelling Vocabulary Logical sentences Sentence combining
Test of Written Expression (TOWE)
McGhee, Bryant, Larson, and Rivera, 1995
6.6–14.11 years
Ideation Semantics Syntax Capitalization Punctuation Spelling Composition/essay
Written Language Assessment
Grill and Kirwin, 1989
8–18 years
General writing ability Productivity Word complexity Readability Written language
Writing Process Test
Warden and Hutchinson, 1992
Grades 2–12
Purpose/focus Audience Vocabulary Style/tone Support/development Organization Sentence structure/variety Grammar/usage Capitalization Spelling
7.6–17.11 years
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Part III • Therapeutic Intervention
tion to visual perception—tactile-proprioceptive, kinesthesia, and praxis aspects require specific attention. Most of these aspects are assessed through structured observation during task performance and are included in Table 14-3. Tactile-proprioceptive processing is necessary to provide the child with information used to grasp the pencil. Kinesthesia provides the child with information that is used to gauge pressure on the pencil and of the pencil on the paper while writing or coloring. In addition, integration of vision and kinesthesia guides the direction of a writing tool. Children who have tactile-proprioceptive or kinesthesia impairments may hold their pencil too firmly or loosely or write with increased or decreased pressure to paper, both of which can influence endurance and quality of writing. Laszlo and Bairstow (1984) proposed that kinesthetic feedback is essential to handwriting development. They proposed that kinesthetic information has two functions in the performance and acquisition of handwriting: It provides ongoing error information, and it is stored in memory to be recalled when the writing is repeated. If kinesthetic information cannot be perceived or used, efficient programming cannot occur. Levine (1987) proposed that kinesthetic impairment in children might lead to decreased speed of handwriting because of either the excessive pressure needed for kinesthetic feedback or the slower visual feedback used to substitute for kinesthetic feedback. In addition, the child who has tactile-proprioceptive or kinesthesia impairment may continue to require visual monitoring of his or her hand for handwriting tasks. A recent study suggested that kinesthetic training did not improve handwriting legibility or kinesthesis in children; therefore evaluation may not offer treatment options but awareness of deficits in the child’s underlying components (Sudsawad et al., 2002). Praxis refers to the planning and performance of a motor movement or task, or a series of motor movements or tasks. Impairments in praxis interfere with letter formation and may be seen initially as initiation deficits. The child may appear to form the letter differently each time and act as if he or she had never been taught proper formation. Further, praxis can impair building words from letters and writing letters or words on an automatic level. Together, assessment of all of the discussed performance components provides information for the therapist to determine current developmental strengths and weaknesses related to handwriting performance. Noted deficits may serve as the foundation for noted handwriting difficulties and are used to interpret the findings of the actual assessment of handwriting performance.
ACTUAL EVALUATION OF HANDWRITING PERFORMANCE The process of gathering information for a comprehensive handwriting evaluation has already largely been completed through observations made during previous testing. Specifically, observations about hand dominance, midline crossing, grasp patterns to a pencil, the firmness of that grasp, and the amount of pressure to paper have all been made during the fine and visual motor assessment. In addition, observations about stability and compensatory movement patterns also have been made. In this section, the focus is on the actual process of handwriting. Initially the domains of handwriting, legibility components, speed of writing, and ergonomic factors are discussed as outlined by Amundson (1992, 2001), followed by a discussion of commercially available assessment tools.
DOMAINS OF HANDWRITING Evaluating the various domains of handwriting allows the therapist to identify which tasks the child is having more difficulty with and address those tasks in the intervention plan (Amundson, 1992). Handwriting skills needed by students are included in Box 14-1.
LEGIBILITY COMPONENTS Legibility deficits in handwriting are often the primary reason for referral for handwriting problems. These
BOX 14-1
Handwriting Skills Needed by Students
• Writing the alphabet and numbers from memory requires that the student remembers letter/number formation, their sequence, and maintains consistent letter case (upper or lower). • Copying. Both near-point (copying from a nearby model) and far-point (copying from a distant model) are used by students to take notes and communicate information. • Manuscript-to-cursive transition requires the student to transcribe manuscript letters and words to cursive letters and words and demands a mastery of both letter forms. • Dictation requires integration of both auditory processing and motor responding. • Composition is a high level task requiring both written language and handwriting elements.
Evaluation of Handwriting • 301 deficits may be caused by a number of components and are assessed by analysis of a writing sample. Letter formation is assessed initially to be sure letters are properly formed and legible. Alignment of letters on a line and in relation to each other is also assessed. Spacing that needs to be addressed includes letters within words, words within sentences, and the organization of the whole page. Another component to be addressed is letter size, which refers to the size of letters within writing guidelines and in relation to each other. Together, all of these qualitative aspects of legibility comprise the components of handwriting that are often the visible evidence of handwriting impairment. Informal evaluation also may include comparing the child to his or her peers in terms of the completion of a writing task during the allotted time and the amount of work completed. Common handwriting problems such as incorrect letter formation, poor alignment, reversals, uneven size of letters, irregular spacing between letters and words, and slow motor speed (Alston & Taylor, 1987; Johnson & Carlisle, 1996) do not necessarily arise from identical underlying mechanisms. Careful observation and evaluation are needed to determine the underlying causes. Two main approaches used in formal assessments to rate handwriting legibility are rating of the legibility components (i.e., slant, size, alignment) and rating of global legibility (i.e., overall readability of writing sample). The assessment of legibility using ratings of legibility components can be extremely time consuming and may not provide a clear picture of the overall readability of a child’s written work (Sudsawad et al., 2001). Often, the components are judged against standard templates, which may not be adaptable to variations in handwriting style. Changes in these components may or may not indicate whether the child’s handwriting is easier or harder to read. The readability of letters, words, and numerals is the primary criterion that determines global legibility. Evaluation of global legibility is quick and simple and addresses the functional aspects of handwriting legibility (Amundson, 1995). The evaluator is more concerned with whether the handwriting can be read with ease than with whether an exact correspondence exists between a handwritten letter and the model letter (Talbert-Johnson et al., 1991). Examples of manuscript writing tests that rate legibility components include The Children’s Handwriting Evaluation Scale for Manuscript Writing (Phelps & Stempel, 1984) and the Minnesota Handwriting Test (Reisman, 1993, 1999). The Evaluation Tool of Children’s Handwriting (Amundson, 1995) evaluates global legibility of manuscript writing.
WRITING SPEED Coupled with legibility, writing speed is a cornerstone of functional handwriting (Amundson, 1995). In general, speed of handwriting decreases as the complexity of a task increases. Therefore speed of writing needs to be addressed within each of the domains of handwriting to determine the impact of the different task demands. Although speed for copying tasks may be adequate, slower handwriting speed for composition task may indicate coexisting formulation deficits. Slow handwriting speed affects functional performance because it prevents students from meeting time constraints involved in schoolwork (Cermak, 1991; Levine et al., 1981). Slow hand writers are different in the way they process written information from normal speed writers. Slow hand writers depend on visual processing, whereas normal speed writers are motor based (Tseng & Chow, 2002). Slow hand writers were poorer as a group than children with normal-speed hand writers in graphomotor output, level of perceptual motor skills, and decreased attention (Tseng & Chow, 2000). Rosenblum, Parush, and Weiss (2003) using a computerized digital system found that nonproficient 8- to 9-year-old handwriters required significantly more time to perform handwriting tasks and that their “in air” time, was especially longer as compared to the proficient handwriters. “In air” time refers to pauses, or temporary halts in the flow of writing (Benbow, 1995; Kaminsky & Powers, 1981). The researchers found this phenomenon not as a pause but rather as a “motion tour” taking place in the air between the writing of successive characters, segments, letters, and words. It may be that the “in air” time helps the student to prepare to execute subsequent characters or character segments. This time may be needed to parameratize the motor program or initiate activity in the muscle groups needed to execute the character. In addition, the researchers found that the nonproficient hand writers’ handwriting speed was slower and they wrote fewer characters per minute. Formal assessments of handwriting speed are included in Table 14-5.
E RGONOMIC FACTORS The ergonomic factors affecting handwriting (e.g., writing posture, grip, stability) have been discussed in the related performance components section, but require further mention here. From the literature, writing tools, paper, and surfaces appear to be important factors in handwriting. In assessing grip it is important to keep in mind the effects of the task and writing tool on the grasp.
No. 2
No. 2
No. 2
Size used by student
Pencil:
X X
X X
X
X
X
X X
X X X X X
X
X
X
X
Grades 1-6
Paper: Lined Unlined
X
X
8–10.11 yrs
X
X
X
Script Assessed: Manuscript Cursive
X
5–8.11 years
No. 2
X X
X X X X X X X
X
X
Grades 1-6
ETCH–Cursive
ETCH– Manuscript
THS– Manuscript THS–Cursive
Evaluation Tool of Children’s Handwriting (ETCH) (Amundson, 1995)
Test of Handwriting Skills (THS) (Gardner, 1998)
Domains Tested: Near-point copying Far-point copying Composition Dictation Upper or lower case Manuscript to cursive Sensorimotor
X
Test Type: Norm-referenced Criterion-referenced
First and second grades
Minnesota Handwriting Assessment (MHA) (Reisman, 1999)
Instruments to assess handwriting
Age/grade Range:
Table 14-5
No. 2
X
X
X
Grades 3-8
Children’s Handwriting Evaluation Scale (CHES) (Phelps & Stempel, 1984)
302 Part III • Therapeutic Intervention
Psychological & Educational Pub
Psychological Corp
Available:
Percent Accurate
X F, Sp, Sz, A
15-30 minutes 10-20 minutes
OT Kids
Items and scoring were developed by literature review and field testing
0.53 to 0.97 for inexperienced raters and from 0.64 to 0.98 for experienced raters Ranged 0.63 to 0.71 for total scores
0.64 to 0.94 for inexperienced raters and from 0.63 to 0.91 for experienced raters
Percent Accurate
X F, Sp, Sz, A
15-30 minutes 10-20 minutes
Quality Rating Key: L=legibility, F=form, A=alignment, Sz=size, Sp=spacing, Sl=slant, R=rhythm, Ap=appearance Scores Yielded Key: PR=percentile rank, Std=standard score, Sc=scaled score, St=stanine
On 839 children from a nationwide sample
2000 first and second grade students from a nationwide sample
0.60 to 0.89 (ICC)
PR, Std, Sc, St
X Sp, A, Sz, F
15-20 minutes 15-20 minutes
Validated:
Test-retest
Intrarater
0.77 to 0.88 for inexperienced raters and from .90 to .99 for experienced raters Ranged from 0.96 to 1
PR, Std, Sc, St
Classification/Rating
Scores Yielded:
Reliability: Interrater
X Sp, A, Sz, F
X L, F, A, Sz, Sp
Assessed: Rate Quality (types)
15-20 minutes 15-20 minutes
ETCH–Cursive
ETCH– Manuscript
THS– Manuscript THS–Cursive
Evaluation Tool of Children’s Handwriting (ETCH) (Amundson, 1995)
Test of Handwriting Skills (THS) (Gardner, 1998)
2.5 minutes 3-7 minutes
Minnesota Handwriting Assessment (MHA) (Reisman, 1999)
Instruments to assess handwriting—cont’d
Time: Administration Scoring
Table 14-5
Author Continued
On 1365 children from Dallas County Schools
Ranging from 0.88 to 0.95
Std, PR
X F, Sl, R, Sp, Ap
2 minutes 3-7 minutes
Children’s Handwriting Evaluation Scale (CHES) (Phelps & Stempel, 1984)
Evaluation of Handwriting • 303
X
Script Assessed: Manuscript Cursive
X No. 2
2 minutes 3-7 minutes
Paper: Lined Unlined
Pencil:
Time: Administration Scoring
No. 2
X X X
X X
X
X
Test Type: Norm-referenced Criterion-referenced
X
X
First and second graders
Age/grade Range:
Domains Tested: Near-point copying Far-point copying Composition Dictation Upper or lower case Manuscript to cursive Sensorimotor
Grades 3-8
CHES–Manuscript (Phelps, 1987)
Instruments to assess handwriting—cont’d Denver Handwriting Analysis (Anderson, 1983)
Table 14-5
3 minutes 2 minutes
No. 2
X
X
X X
X
3-12 years
Handwriting Speed Test (Wallen et al, 1996a)
X
X X
X
7-18.5 years
Test of Legible Handwriting (Larsen & Hammill, 1989)
3 minutes 2 minutes
No. 2
X
X
X
Grades 2-6
Chinese Speed Test (Tseng, 1998)
304 Part III • Therapeutic Intervention
Quality Rating Key: L=legibility, F=form, A=alignment, Sz=size, Sp=spacing, Sl=slant, R=rhythm, Ap=appearance Scores Yielded Key: Pr=percentile rank, Std=standard score, Sc=scaled score, St=stanine
Helios Art & Book
Author
Available:
Out of print
On 1292 Australian students
On 643 Dallas County School students
Ranged from 0.98 to 1 Ranged from 0.71 to 0.92
Ranged from 0.99 to 1
Std
X
Handwriting Speed Test (Wallen et al, 1996a)
Validated:
Test-retest
Intrarater
Ranged from 0.85 to 0.93
Pr
Std, Pr
Scores Yielded:
Reliability: Interrater
X
X F, Sp, R, Ap
CHES–Manuscript (Phelps, 1987)
Denver Handwriting Analysis (Anderson, 1983)
Instruments to assess handwriting—cont’d
Assessed: Rate Quality (types)
Table 14-5
Out of print
Std, Pr
Test of Legible Handwriting (Larsen & Hammill, 1989)
Author
On 1525 Chinese students
Reported to be 0.98
Reported to be 0.95
Std, Pr
X
Chinese Speed Test (Tseng, 1998)
Evaluation of Handwriting • 305
306
Part III • Therapeutic Intervention
Children used a less mature grasp in coloring than drawing (Schneck, 1991). Young children aged 23 to 24 months used a more mature grasp when drawing with a piece of crayon than with a pencil (Yakimishyn & Magill-Evans, 2002). In addition, no difference in grasp maturity was found when using a pencil compared with a marker. Lastly, a more mature grasp was demonstrated when drawing on the easel compared with the table when using a crayon, not with a marker or pencil. Krzesni (1971) found a significant increase in writing performance with a felt pen. However, Lamme and Aynis (1983) found that writing tools did not affect legibility. Several studies have extended the effects of writing paper on handwriting performance. Lindsay and McLennan (1983) and Weil and Amundson (1994) reported that for beginning writers, lined paper may add an element of confusion and compromise legibility. Krzesni (1971) found the opposite is true for older children; legibility improved with lined paper in 9-yearold children. Halpin and Halpin (1976) compared handwriting quality in kindergarten children with 1and 11/2-inch–spaced paper and found no difference.
KEYBOARDING PERFORMANCE Sixth-grade students demonstrated low to moderate correlation between keyboarding and handwriting performance (Rogers & Case-Smith, 2002). This suggests that these forms of written expression require distinctly different skills. Most students who were slow at handwriting or had poor legibility increased the quantity and overall legibility of the text they produced with a keyboard. This suggests that it is important to assess keyboarding in nonproficient writers because it may simplify their text production. It may allow certain children to concentrate on content and meaning when composing and encourage them to engage in compositional writing.
COMMERCIALLY AVAILABLE ASSESSMENT TOOLS Several handwriting assessment tools are commercially available. Although Table 14-5 provides a graphic summary of these instruments, Appendix 14A also provides an in-depth analysis of each of the instruments that is still currently available and summarizes some findings. As can be seen by analyzing Appendix 14A, few quality instruments specifically designed to assess handwriting are available. Selecting the most appropriate instrument is dependent on the individual needs of the evaluating therapist. In selecting a handwriting instrument, therapists must not only consider a child’s area of handwriting difficulty, but also the psychometric
properties of the instrument chosen. In the opinion of the present authors, of the available instruments the Minnesota Handwriting Assessment (MHA) (Reisman, 1999), Test of Handwriting Skills (THS) (Gardner, 1998), and Evaluation Tool of Children’s Handwriting (ETCH) (Amundson, 1995) are the most useful. These instruments could be used in any number of settings. Each of these instruments provides for assessment of both legibility and rate or speed aspects of handwriting. All of the instruments also have in-depth scoring procedures that allow determination of the most common legibility errors. The MHA has the most limited scope in that it is an assessment of near point copying only and can be used for first and second graders only. The flexibility for the assessment of both manuscript and D’Nealian script, its short administration time, and its relatively short scoring time make it attractive for clinical practice. A categoric scoring summary on the MHA allows comparison to peers and can be used to determine the need for intervention. Given these test constructs it is the recommended instrument for first and second graders experiencing difficulties with learning the writing process. For students older than second grade, the THS and ETCH are the recommended instruments for use. Both of these instruments allow for assessment of rate and quality of writing within a number of handwriting domains (e.g., copying, dictation, composition) and have similar administration and scoring times. The ETCH allows assessment of more domains of handwriting and, in addition, addresses sensorimotor aspects of handwriting as part of the assessment. Given these added benefits of the ETCH, it is the recommended assessment for children in this age group. However, one drawback to its use is its lack of normative data (scoring results in a percentage of accuracy). Therefore if normative data are necessary for eligibility or other purposes, only the THS provides this information of the two in this age group. Of the other instruments, the Children’s Handwriting Evaluation Scale (CHES) (Phelps & Stempel, 1984) and Children’s Handwriting Evaluation Scale for Manuscript Writing (CHES-M) (Phelps, 1987) were validated approximately 15 years previously and on a convenient sample of students in a school system in Texas. In addition, test composition factors relating to the scoring of quality and its resultant interpretation, and the use of unlined paper cause concern. Given these factors the overall value and validity of these two instruments is questioned. Although the Handwriting Speed Test (HST) (Wallen, Bonney, & Lennox, 1996a,b) may be useful if determining how a student’s handwriting speed compares to others, its lack of legibility scoring makes its uses limited. Further, given
Evaluation of Handwriting • 307 its validation on a sample of students from Australia only, the reliability and validity of finding are questioned also. It is important to note that when comparing Table 14-5 to the instruments in this Appendix, two of the instruments, the Denver Handwriting Analysis (Anderson, 1983) and Test of Legible Handwriting (Larsen & Hammill, 1989) are no longer commercially available and therefore are not reviewed here. When discussing the out-of-print status with the respective publishers, both stated that there was little demand for the instruments, which is interesting given the fact that handwriting difficulties are a primary reason for referral to occupational therapy. However, this supports the findings of a recent investigation that found that standardized handwriting assessments were rarely employed in assessment of handwriting (Feder, Majnmer, & Synnes, 2000).
SUMMARY As can be seen by this discussion, the assessment of handwriting difficulty is a complex multifaceted process. Administration of a formalized assessment of handwriting alone does not provide the information necessary to determine the root of the difficulty or effectively plan a program. Stability, visual perception, motor performance, written language, and sensory processing aspects of development serve as the foundations for developing the skill of handwriting. Thus although administration of a formalized assessment of handwriting can determine the nature of handwriting difficulty demonstrated by a child, assessment of the related performance components provides the basis for determining the potential cause(s) of the impairments. Identification of these causes allows appropriate intervention planning to develop remediation of the handwriting impairments.
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Gardner MF (1995). Test of visual-motor skills – revised manual. Los Angeles, Western Psychological Services. Gardner MF (1997). Test of visual-perceptual skills upper limits (non-motor) manual. Los Angeles, Western Psychological Services. Gardner M (1998). The test of handwriting skills: manual. Hydesville, CA, Psychological and Educational Publications. Graham S (1992). Issues in handwriting instruction. Focus on Exceptional Children, 25:1–14. Graham S, Berninger V, Abbott R, Abbott S, Whitaker D (1997). The role of mechanics in composing of elementary school students: A new methodological approach. Journal of Educational Psychology, 89:170–182. Grill JJ, Kirwin MM (1989). Written language assessment. Novato, CA, Academic Therapy Publications. Halpin G, Halpin G (1976). Special paper for beginning handwriting: An unjustified practice? Journal of Educational Research, 69:267-269. Hammerschmidt SL, Sudsawad P (2004). Teacher’s survey on problems with handwriting: Referral, evaluation, and outcomes. American Journal of Occupational Therapy, 58:185–191. Hammill DD, Pearson NA, Voress JK (1993). Developmental test of visual perception – second edition. Austin, TX, PRO-ED. Hammill DD, Larsen SC (1996). Test of written language – third edition. Austin, TX, PRO-ED. Hresko WP, Herron SR, Peak PK (1996). Test of early written language. Austin, TX, PRO-ED. Johnson DJ, Carlisle JF (1996). A study of handwriting in written stories of normal and learning disabled children. Reading & Writing, 8:45-59. Kaminsky L, Powers R (1981). Remediation of handwriting difficulties: A practical approach. Academic Therapy, 17:19–25. Krzesni, J (1971). Effect of different writing tools and paper on performance of the third grader. Elementary English, 48:821-824. Lamme LL., Ayris BM (1983). Is the handwriting of beginning writers influenced by writing tools? Journal of Research and Development in Education, 17:32-38. Lane SJ, Miller LJ, Hanft B (2000). Towards a consensus in terminology in sensory integration theory and practice: Part two. Sensory integration: Patterns of function and dysfunction. Sensory Integration Special Interest Section Newsletter, 1–4. Larsen SC, Hammill DD (1989). Test of legible handwriting. Austin, TX, PRO-ED. Laszlo JI, Bairstow PJ (1984). Handwriting difficulties and possible solutions. School Psychology International, 5:207–213. Levine MD (1987). Developmental variation and learning disorders. Cambridge, Educators Publishing. Levine MD, Oberklaid F, Meltzer L (1981). Developmental output failure: A study of low productivity in school-aged children. Pediatrics, 67:18–25. Lindsay GA, McLennan D (1983). Lined paper: Its effects on the legibility and creativity of young children’s writing. British Journal of Educational Psychology, 53:364-368. Maeland AF (1992). Handwriting and perceptual-motor skills in clumsy, dysgraphic, and ‘normal’ children. Perceptual & Motor Skills, 75:1207-17. McGhee R, Bryant B, Larson S, Rivera D (1995). Test of written expression. Circle Pines, MN, American Guidance Service.
McHale K, Cermak S (1992). Fine-motor activities in elementary school: Preliminary findings and provisional implications for children with fine motor problems. American Journal of Occupational Therapy, 46:898–903. Miller LJ, Roid GH (1994). The T.I.M.E.: Toddler and infant motor evaluation. Tucson, AZ, Therapy Skill Builders. Peterson CQ, Nelson DL (2003). Effect of an occupational intervention on printing in children with economic disadvantages. American Journal of Occupational Therapy, 57:152–160. Phelps J (1987). Children’s handwriting evaluation scale for manuscript writing. Dallas, TX, Scottish Rite Hospital for Crippled Children. Phelps J, Stempel L (1984). Children’s handwriting evaluation scale. Dallas, TX, Scottish Rite Hospital for Crippled Children. Reisman JE (1991). Poor handwriting: Who is referred? American Journal of Occupational Therapy, 45:849–852. Reisman JE (1993). Development and reliability of the research version of the Minnesota Handwriting Test. Physical and Occupational Therapy in Pediatrics, 13:41–55. Reisman JE (1999). Minnesota handwriting assessment. Los Angeles, Psychological Corporation. Rogers J, Case-Smith J (2002). Relationships between handwriting and keyboarding performance of sixth-grade students. American Journal of Occupational Therapy, 56:34–39 Rosenblum S, Parush S, Weiss PL (2003). Computerized temporal handwriting characteristics of proficient and non-proficient handwriters. American Journal of Occupational Therapy, 57:129-38. Schneck CM (1991). Comparison of pencil-grip patterns in first graders with good and poor writing skills. American Journal of Occupational Therapy, 45:701–706. Schneck CM (2001). Visual perception. In J Case-Smith, editor: Occupational therapy for children, 4th ed. St Louis, Mosby. Schneck CM, Henderson A (1990). Descriptive analysis of the developmental progression of grip position for pencil and crayon in nondysfunctional children. American Journal of Occupational Therapy, 44:893–900. Solvik N (1975). Developmental cybernetics of handwriting and graphic behavior. Oslo, Norway, Universitetsforlaget. Solvik N, Arntzen O (1991). A developmental study of the relation between the movement patterns in letter combinations (words) and writing. In J Wann, A Wing & N Solvik (editors), Development of graphic skills: Research, perspectives and educational implications (pp. 77-89). London, Academic Press. Sudsawad P, Trombly CA, Henderson A, Tickle-Degnen L (2001). The relationship between the Evaluation Tool of Children’s Handwriting and teachers’ perceptions of handwriting legibility. American Journal of Occupational Therapy, 55:518–523. Sudsawad P, Trombly CA, Henderson A, Tickle-Degnen L (2002). Testing the effect of kinesthetic training on handwriting performance in first-grade students. American Journal of Occupational Therapy, 55:26–33. Sweedler-Brown CO (1992). The effects of training on the appearance basis of holistic essay graders. Journal of Research and Development in Education, 26:24–88. Talbert-Johnson C, Salva E, Sweeney QJ, Cooper JO (1991). Cursive handwriting: Measurement of function rather than topography. Journal of Educational Research, 85:117–124.
Evaluation of Handwriting • 309 Thomassen JW, Teulings HW (1983). The development of handwriting. In M Martlew, editor: The psychology of written language: Developmental and education perspectives (pp. 170–213). New York, Wiley. Tseng MH (1998). Development of pencil grip position in preschool children. Occupational Therapy Journal of Research, 18:207–224. Tseng MH, Cermak SA (1993). The influence of ergonomic factors and perceptual-motor abilities in handwriting performance. American Journal of Occupational Therapy, 47:919–926. Tseng MH, Chow SMK (2002). Perceptual-motor function of school-age children with slow handwriting speed. American Journal of Occupational Therapy, 54:83–88. Tseng MH, Murray EA (1994). Differences in perceptualmotor measures in children with good and poor handwriting. Occupational Therapy Journal of Research, 14:19–36. Tsurumi K, Todd V (1988). Tests of visual perception: What do they tell us? School System Special Interest Section Quarterly, 5(4): 1–4.
Ulrich DA (2000). Test of gross motor development – second edition. Austin, TX, Pro-Ed. Wallen M, Bonney M, Lennox L (1996a). The handwriting speed test. Adelaide, Australia, Helios. Wallen M, Bonney M, Lennox L (1996b). Interrater reliability of the Handwriting Speed Test. Occupational Therapy Journal of Research, 16:280–287. Warden MR, Hutchinson TA (1992). Writing process test. Chicago, Riverside Publishing Company. Weil MJ, Amundson SJC (1994). Relationship between visuomotor and handwriting skills of children in kindergarten. American Journal of Occupational Therapy, 48:982–988. Yakimishyn JE, Magill-Evans J (2002). Comparisons among tools, surface orientation, and pencil grasp for children 23 months of age. American Journal of Occupational Therapy, 56:564–572.
Appendix
14A
HANDWRITING ASSESSMENT INSTRUMENTS
MINNESOTA HANDWRITING ASSESSMENT
categories (Legibility, Form, Alignment, Size, and Spacing) for each letter of the sample. Does it give a clinical diagnosis? No.
AUTHOR, YEAR
PURPOSE
Reisman, 1999
The MHA was designed to help meet the needs of many school districts and special education departments that require a handwriting assessment to support the teacher’s subjective judgment of poor quality or slow rate (Reisman, 1999). It is recommended that interpretive ratings obtained after scoring the MHA be used to guide the need for further assessment and the intervention process.
DESCRIPTION The Minnesota Handwriting Assessment (MHA) is used to assess manuscript and D’Nealian handwriting in first and second graders who have knowledge of the English language. The MHA assesses Rate for the whole writing sample and five quality categories for each letter of the sample: Legibility, Form, Alignment, Size, and Spacing. Subjective quality ratings are collected and yield interpretive cutoff scores within each category: Performing like peers (top 75% of the final sample), performing somewhat below peers (within the bottom 5% and 25% of the final sample), or performing well below peers (bottom 5% of the final sample). It is recommended that students performing somewhat below peers should be monitored to determine if ongoing instruction or practice is needed or whether the student is demonstrating delayed development of underlying hand skills. It is recommended that students performing in the well-below-peers category be referred for comprehensive evaluation to determine the cause of handwriting difficulties.
CONTENTS What does the schedule try to measure? The MHA assesses handwriting performance. Specifically measured are Rate for the whole writing sample and five quality
ASSESSMENT COMPONENTS Type of Assessment: Near-point copy assessment Task(s): The student is required to copy from a printed stimulus sheet onto lines below the words “the brown jumped lazy fox quick dogs over.” The mixed word order of the sentence is used to reduce the speed and memory advantage of better readers by requiring all students to refer to the stimulus items word by word. Paper Type: Supplied lined paper with center dotted line Pencil Type: Any size pencil typically used by the student
ADMINISTRATIVE /SCORING TIME Administration: The test is timed for the first 21/2 minutes to obtain the Rate score and then, if necessary, the students are given time to complete the sample to allow for scoring the five quality categories.
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Scoring: After some experience with the instrument (30 samples), scoring time ranges from 3 to 7 minutes. From experience, scoring takes closer to 10 to 12 minutes.
PARTICIPANTS Children: First and second graders Developmental Level: Grade level
DERIVATION Writing sample and scoring criteria were developed from a pilot version, through literature review and field testing with revision.
PUBLISHED MATERIAL Author/Others: author (Reisman, 1993, 1999); others (Peterson, 1999) Usefulness: The MHA was designed to help meet the needs of many school districts and special education departments that require a handwriting assessment to support the teacher’s subjective judgment of poor quality or slow rate (Reisman, 1999). Validated: On 2000 first- and second-grade students from a nationwide sample (Reisman, 1993, 1999) with cutoff scores determined after analysis. Content validity was established in development. Reliability: Interrater ranged from 0.77 to 0.88 (Pearson) for inexperienced raters and from 0.90 to 0.99 for experienced raters. Intrarater reliability (5to 7-day interval) ranged from 0.96 to 1. Test-retest stability (5- to 7-day interval) for performance level ranged from 64% to 86%. Test-retest reliability was conducted in a related study (Peterson, 1999) with at-risk students with correlations ranging from 0.60 to 0.89 (Internal Consistency Coefficient ICC). Additional Statistical Analysis: A special group study was conducted to examine first- and second-grade students in regular education, special education, and special education plus occupational therapy. Scores on the MHA and Test of Visual Motor Skills (a design copying visual motor control test) were compared with correlations ranging from 0.37 (second grade) to 0.89 (occupational therapy).
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS Is a helpful tool in discerning the types of handwriting errors exhibited by first- and second-grade students. Quality scoring for each letter provides a mechanism for focusing treatment and evaluating progress. Its short administration and scoring time make it advan-
tageous to clinical practice. Reliability findings may be inflated because of use of Pearson for statistical analysis (Ottenbacher & Tomchek, 1993, 1994).
REFERENCES Ottenbacher KJ, Tomchek SD (1993). Reliability analysis in therapeutic research: Practice and procedures. American Journal of Occupational Therapy, 47(1):10–16. Ottenbacher KJ, Tomchek SD (1994). Measurement error in method comparison studies: An empirical examination. Archives of Physical Medicine & Rehabilitation, 75(5):505–512. Peterson CQ (1999). The effect of an occupational therapy intervention handwriting in academically atrisk first graders. Unpublished doctoral dissertation. Cincinnati, The Union Institute Graduate School. Reisman JE (1993). Development and reliability of the research version of the Minnesota Handwriting Test. Physical and Occupational Therapy in Pediatrics, 13:41–55. Reisman JE (1999). Minnesota handwriting assessment. Los Angeles, Psychological Corporation.
TEST OF HANDWRITING SKILLS AUTHOR, YEAR Gardner, 1998
DESCRIPTION The Test of Handwriting Skills (THS) is used to assess a child’s neurosensory integration ability in handwriting either manuscript or cursive and in upper and lower case forms, and to measure the speed with which a child handwrites from: writing from memory, upper and lower case letters of the alphabet in sequence; writing from dictation, upper and lower case letters of the alphabet out of sequence; writing from dictation, numbers out of numeric sequence; copying selected letters from the alphabet; copying selected words; copying selected sentences; and writing from dictation selected words. Although the purpose of the THS is to measure how a child (ages 5 years, 0 months to 10 years, 11 months) can write letters, words, and numbers spontaneously, from dictation, or from copying, it is also used to determine the speed by which a child can produce letters spontaneously. Each of the 206 letters in the sample is scored using a four-point scale. The THS provides normative data in 3-month increments for each subtest (standard scores, scaled scores, percentile ranks, and stanines).
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CONTENTS
PARTICIPANTS
What does the schedule try to measure? The THS measures quality of handwriting in children. In addition to the 206 scorable-language symbols, the THS, Manuscript version (for children ages 5 years to 8 years 11 months) has reversal of letters, letters touch one another, speed of writing letters spontaneously from memory, and converting lower case letters to upper case letters, and vice versa special features. The THS, Cursive version (for children ages 8 years to 10 years 11 months) has in addition to the 206 scorable letters, only one feature: speed of writing letters spontaneously from memory. Does it give a clinical diagnosis? No.
Children: Ages 5 years, 0 months to 10 years 11 months Developmental Level: Grade level
PURPOSE The purpose of the THS is to measure how a child can write letters, words, and numbers spontaneously, from dictation, or from copying. It is also used to determine the speed by which a child can produce letters spontaneously. These components of the assessment can identify both the strengths and weaknesses of a child’s handwriting that can be used to develop a remedial program. The goal of remediation is to improve a child’s legibility of letters, words, and numbers, along with increasing speed of writing.
DERIVATION Overall test developed based on literature review. Words used in dictation components were determined by a group of 15 teachers.
PUBLISHED MATERIAL Author/Others: Author (Gardner, 1998); others Usefulness: Quality and rate findings of the assessment are used to identify both the strengths and weaknesses of a child’s handwriting that can be used to develop a remedial program. Validated: On 839 children (Gardner, 1998) from a nationwide sample with normative data determined after analysis. Construct validity was in the moderate range. Concurrent validity studies yielded positive correlations with the TVMS-R, WRAT-3 (spelling component), Bender, and VMI. Reliability: Internal consistency was described as “acceptable” with reliability coefficients ranging from .51 to .78. Additional Statistical Analysis: None
ASSESSMENT COMPONENTS Type of Assessment: Spontaneous composition, dictation and near-point copy assessment Task(s): (a) Writing from memory, upper case letters of the alphabet in sequence; (b) writing from memory, lower case letters of the alphabet in sequence; (c) writing from dictation, upper case letters of the alphabet out of sequence; (d) writing from dictation, lower case letters of the alphabet out of sequence; (e) writing from dictation, numbers out of numerical sequence; (f) copying selected upper case letters from the alphabet; (g) copying selected lower case letters from the alphabet; (h) copying selected words; (i) copying selected sentences; and (j) writing from dictation selected words. Paper Type: Supplied unlined paper in test booklet Pencil Type: Standard number 2 pencil
ADMINISTRATION /SCORING TIME Administration: The test can be administered in 15 to 20 minutes. Scoring: After some practice, scoring time ranges from 15 to 20 minutes. From experience, scoring takes all of 20 minutes.
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS Helpful tool in discerning the types of handwriting errors exhibited by students. Cumbersome scoring and lengthy administration may inhibit frequent use in clinical practice. The use of unlined paper for this assessment may facilitate further handwriting impairments in that several studies have shown that children’s handwriting on unlined paper when compared with lined paper is poorer in quality (Alston & Taylor, 1987; Burnhill et al., 1983; Pasternicki, 1984).
REFERENCES Alston J, Taylor J (1987). Handwriting: Theory, research, and practice. Worcester, MA, Billings. Burnhill P, Hartley J, Lindsay D (1983). Lined paper, legibility and creativity. In J Hartley, editor: The psychology of written communication. London, Kogan Page. Gardner M (1998). The test of handwriting skills: manual. Hydesville, CA, Psychological and Educational Publications.
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Pasternicki JG (1984). Teaching handwriting: The resolution of an issue. Support for Learning, 1:37–41.
CHILDREN’S HANDWRITING EVALUATION SCALE AUTHOR, YEAR
ADMINISTRATIVE /SCORING TIME Administration: The test is timed for the first 2 minutes to obtain the Rate score and then, if necessary, the students are given time to complete the sample to allow for scoring the quality categories. Scoring: Scoring time ranges from 3 to 7 minutes.
PARTICIPANTS Children: Third through eighth graders Developmental Level: Grade level
Phelps and Stempel (1984)
DESCRIPTION The Children’s Handwriting Evaluation Scale (CHES) is used to assess cursive handwriting in third through eighth graders who have knowledge of the English language. The CHES assesses Rate to copy the passage (consisting of 197 letters) and five quality categories of the sample: Form, Slant, Rhythm, Space, and General Appearance. Rate and quality are evaluated independently on a five-point scale: very poor, poor, satisfactory, good, and very good. Percentile ranges can be assigned to correspond with rankings. In addition, percentile, standard scores, T-scores, and stanines are provided for Rate of writing for each grade.
CONTENTS What does the schedule try to measure? The CHES assesses handwriting performance. Specifically, Rate for the whole writing sample and five quality categories (form, slant, rhythm, space, and general appearance) for the whole sample are measured. Does it give a clinical diagnosis? No.
PURPOSE The main purpose is to assess the rate and quality of a student’s handwriting. It is recommended that interpretive ratings obtained after scoring the CHES be used to guide need for further assessment and the remediation process.
ASSESSMENT COMPONENTS Type of Assessment: Near-point copy assessment Task(s): The student is required to copy a passage from a printed stimulus sheet directly below Paper Type: Supplied unlined blank sheet with the passage on top Pencil Type: Number 2 pencil
DERIVATION No information identified.
PUBLISHED MATERIAL Author/Others: Author (Phelps & Stempel, 1984); others Usefulness: Interpretive ratings obtained after scoring the CHES should be used to guide need for further assessment and the remediation process. Validated: On 1365 third- through eighth-grade students in Dallas County Schools (Phelps & Stempel, 1984) with cutoff scores determined after analysis. Content validity was established in development (Phelps & Stempel, 1984). Reliability: Interrater ranged from 0.88 to 0.95 (ICC). Additional Statistical Analysis: The reasons for need for remediation (performance below the 24th percentile) were studied with 9% needing remediation for quality only, 13% for rate only, and 2% for both rate and quality. In addition, rate scores for the CHES were compared with rate scores for the American Handwriting Scale (1957) (no longer available). Findings showed that students in 1984 wrote at a slower rate than in 1957 and that the AHS yielded more letters of writing at all grade levels.
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS Useful primarily for rate scoring in that the five-point total quality scoring for whole sample lacks sensitivity to define specific handwriting problems. The short time to administer and score is a positive. Questionable reliability and validity given the convenient sample obtained from only Dallas County Schools. Validity of findings are also questioned given the tool’s use of unlined paper.
Evaluation of Handwriting • 315
REFERENCE
standard by which to monitor gradual improvement or immediately define specific problem areas.
Phelps J, Stempel L (1984). Children’s handwriting evaluation scale. Dallas, TX, Scottish Rite Hospital for Crippled Children.
ASSESSMENT COMPONENTS
CHILDREN’S HANDWRITING EVALUATION SCALE FOR MANUSCRIPT WRITING (CHES-M)
Type of Assessment: Near-point copy assessment Task(s): The student is required to copy two sentences (57 total letters) on a printed stimulus sheet directly below. Paper Type: Supplied unlined blank sheet with the passage on top Pencil Type: Number 2 pencil
AUTHOR, YEAR Phelps, 1987
DESCRIPTION The CHES-M is used to assess manuscript handwriting in first and second graders who have knowledge of the English language. The CHES-M assesses Rate to copy the sentences (consisting of 57 letters) and 10 quality components in four main categories: Form, Rhythm, Space and General Appearance. Rate and Quality are evaluated independently. Percentile ranks and standard scores are provided for Rate of writing for each grade. With respect to quality ratings, 10 points were assigned to each constituent. When all are present, 100 points are possible with 10 points deducted for each criterion not met. Scores between 10 and 40 are considered poor; between 50 and 70, satisfactory; and between 80 and 100 good. Percentile ranks and standard scores are provided for a quality total score based on rating.
CONTENTS What does the schedule try to measure? The CHES-M assesses handwriting performance. Specifically, the CHES-M measures Rate for the whole writing sample and four quality categories: Form (small letters are uniform in height and proportion, tall letters are higher than small and suitably proportioned and aligned, correctly formed and recognizable out of context, letters copied correctly); Space (space between letters of a word uniform, space between words adequate and uniform, right margin uncrowded, space between lines uniform); Rhythm; and General Appearance Does it give a clinical diagnosis? No.
PURPOSE The main purpose is to measure rate and quality of manuscript handwriting. It is intended to provide a
ADMINISTRATIVE /SCORING TIME Administration: The test is timed for 2 minutes. If the student finishes before 2 minutes, he or she is asked to start again. Scoring: Scoring time ranges from 3 to 7 minutes.
PARTICIPANTS Children: First and second graders Developmental Level: Grade level
DERIVATION Derived from the CHES with the same schools used for norming purposes.
PUBLISHED MATERIAL Author/Others: Author (Phelps, 1987); others Usefulness: It is intended to provide a standard by which to monitor gradual improvement or immediately define specific problem areas. Validated: On 643 first- and second-grade students in Dallas County Schools (Phelps & Stempel, 1984) with cutoff scores determined after analysis. Content validity was established in development. Reliability: Interrater ranged from 0.85 to 0.93 (ICC). Additional Statistical Analysis: None.
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS Short administration and scoring time are benefits to use in clinical practice. Significant questions relating to reliability and validity given the convenient sample obtained from only Dallas County Schools. Validity of findings is also questioned given the tools use of unlined paper.
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REFERENCE
ASSESSMENT COMPONENTS
Phelps J (1987). Children’s handwriting evaluation scale for manuscript writing. Dallas, TX, Scottish Rite Hospital for Crippled Children.
Type of Assessment: Spontaneous composition, dictation, near-point, and far-point copy assessment Task(s): The ETCH-C has the following tasks: (a) writing from memory, upper and lower case letters of the alphabet in sequence; (b) writing from memory, the numbers 1 to 20 in sequence; (c) near-point copying a short sentence; (d) far-point copying a short sentence; (e) manuscript-to-cursive transition a short sentence; (f) dictation three nonsense words; and (g) sentence composition. The ETCH-M consists of all of the preceding subtests with the exception of manuscript-to-cursive transition. Paper Type: Supplied lined paper in test booklet Pencil Type: Standard number 2 pencil
EVALUATION TOOL OF CHILDREN’S HANDWRITING AUTHOR, YEAR Amundson, 1995
DESCRIPTION The Evaluation Tool of Children’s Handwriting (ETCH) is designed to evaluate manuscript (ETCHM) and cursive (ETCH-C) handwriting skills of children in grades 1 through 6 who are experiencing difficulty with written communication. The ETCH contains seven cursive writing tasks and six manuscript writing tasks, plus items addressing the child’s ability to handle the writing tool and paper. The primary focus of the ETCH is to assess a child’s legibility and speed of handwriting in writing tasks that are similar to those required of students in the classroom. The ETCH also examines specific legibility components of a child’s handwriting such as letter formation, spacing, size, and alignment, as well as a variety of sensorimotor skills related to the child’s handling of the writing tool and paper. Subtest and ETCH total scores are calculated as percentages on the basis of the number of readable letters, words, and numbers against possible letters, words, and numbers.
CONTENTS What does the schedule try to measure? The ETCH examines specific legibility components of a child’s handwriting (manuscript or cursive) such as letter formation, spacing, size, and alignment, as well as a variety of sensorimotor skills related to the child’s handling of the writing tool and paper. These components are measured from spontaneous composition, dictation, near-point, and far-point copying tasks. Does it give a clinical diagnosis? No.
PURPOSE The primary purpose of the ETCH is to assess a child’s legibility and speed of handwriting in writing tasks that are similar to those required of students in the classroom.
ADMINISTRATIVE /SCORING TIME Administration: The test can be administered in 15 to 30 minutes depending on the child’s age and handwriting difficulties Scoring: After some practice, scoring time ranges from 10 to 20 minutes. From experience, scoring takes all of 20 minutes.
PARTICIPANTS Children: Children in grades 1 through 6, ages 6 years, 0 months to 12 years, 5 months Adults: Can be used to gather descriptive information related to their functional handwriting performance. Developmental Level: Grade level
DERIVATION Writing sample and scoring criteria were developed from a pilot version through literature review and field testing with revision.
PUBLISHED MATERIAL Author/Others: Author (Amundson, 1995); others (Diekema, Deitz, & Amundson, 1998; GraceFrederick, 1998; Koziatek & Powell, 2002; Schneck, 1998; Sudsawad et al., 2001) Usefulness: Useful in assessing a child’s legibility and speed of handwriting in writing tasks that are similar to those required of students in the classroom. This is useful in analyzing underlying sensorimotor functions of handwriting and assessing handwriting quality to determine the need for intervention and baseline for monitoring progress. Validated: Although one construct validity study (Grace-Frederick, 1998) showed agreement between teacher ratings of poor handwriting and poor per-
Evaluation of Handwriting • 317 formance on the ETCH, another study (Sudsawad et al., 2001) reported that little agreement was noted between teacher questionnaires of handwriting difficulty and ETCH performance. The concurrent validity coefficients were 0.61 for ETCH-C total words and 0.65 for total letters and handwriting grade. Reliability: Interrater ranged from 0.64 to 0.94 (Pearson) for inexperienced raters and from 0.63 to 0.91 for experienced and inexperienced raters. Intrarater reliability ranged from 0.53 to 0.97 for inexperienced raters and from 0.64 to 0.98 for experienced and inexperienced raters. Test-retest reliability was conducted in a related study (Diekema et al., 1998) with correlations ranging from 0.63 to 0.71 (Pearson) for total numeral, letter and legibility, with generally lower subtest coefficients (0.20 to 0.76). Additional Statistical Analysis: None
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS One of the more widely used instruments, although it lacks normative data. Thorough manual and templates eliminate the need for constant ordering of forms. Useful in identifying the types of handwriting difficulties a student may be having, as well as potential underlying sensorimotor difficulties. It is cumbersome scoring a negative. Reliability findings also are questioned given the use of the Pearson (Ottenbacher & Tomchek, 1993, 1994).
REFERENCES Amundson SJ (1995). The evaluation tool of children’s handwriting (ETCH). Homer, AK, OT Kids. Diekema SM, Deitz J, Amundson SJ (1998). Testretest reliability of the Evaluation Tool of Children’s Handwriting, Manuscript. American Journal of Occupational Therapy, 52:248–254 Grace-Frederick L. (1998). Printing, legibility, pencil grasp, and the use of the ETCH-M. Boston, Boston University, Unpublished master’s thesis. Koziatek SM, Powell NJ (2002). A validity study of the Evaluation Tool of Children’s Handwriting-Cursive. American Journal of Occupational Therapy, 56:446–453. Ottenbacher KJ, Tomchek SD (1994). Measurement error in method comparison studies: An empirical examination. Archives of Physical Medicine & Rehabilitation, 75(5):505–512. Schneck CM (1998). Clinical interpretation of TestRetest Reliability of the Evaluation Tool of Children’s Handwriting-Manuscript. American Journal of Occupational Therapy, 52:256–258.
Sudsawad P, Trombly CA, Henderson A, Tickle-Degnen L (2001). The relationship between the Evaluation Tool of Children’s Handwriting and teacher’s perceptions of handwriting legibility. American Journal of Occupational Therapy, 55:518–523.
HANDWRITING SPEED TEST AUTHOR, YEAR Wallen, Bonney, and Lennox (1996a,b)
DESCRIPTION The Handwriting Speed Test (HST) is a standardized, norm-referenced test of handwriting speed for children and adolescents in grades 3 through 12. It is intended to be used as one component of a multifaceted assessment of handwriting. After a 3-minute trial of copying the words “the quick brown fox jumps over the lazy dog” as many times as they can, a letters per minute is obtained and converted to a scaled score. The scaled score can be used in determining the eligibility of students for extra time or other assistance in examinations, identifying children who require intervention for handwriting speed difficulty, and evaluating the effects of intervention on handwriting.
CONTENTS What does the schedule try to measure? Handwriting speed for children and adolescents in grades 3 through 12. Does it give a clinical diagnosis? No.
PURPOSE The HST was developed to provide an up-to-date and objective means of evaluating the handwriting speed of students presenting with handwriting difficulties.
ASSESSMENT COMPONENTS Type of Assessment: Near-point copy assessment Task(s): The student is asked to copy from a typed Handwriting Sample Form onto lines below the words “the quick brown fox jumps over the lazy dog” as many times as they can in a 3-minute period. Paper Type: Supplied lined paper with center dotted line Pencil Type: Number 2
ADMINISTRATIVE /SCORING TIME Administration: The test is timed for 3 minutes to obtain the Rate score. Scoring: Scoring time ranges from 3 to 5 minutes.
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PARTICIPANTS Children: Third through twelfth graders Adults: Young adult (high school aged) Developmental Level: Can be used for children with physical disabilities, learning disabilities, or specific handwriting difficulties
DERIVATION
Reliability: Interrater ranges from 0.99 to 1.00 (ICC) for each grade and an ICC of 1.00 for the whole sample. Intrarater reliability ICC was 0.99 for the whole sample and ranged from 0.99 to 1.00 for various grades, teacher ratings, and genders of students. Test-retest reliability correlations ranged from 0.717 to 0.916 (ICC) for the various grades and speeds of hand writers. Additional Statistical Analysis: None
Writing sample and scoring criteria were developed through literature review
OTHER DATA IN SCHEDULE /OTHER I NFORMATION /COMMENTS
PUBLISHED MATERIAL
Its short administration and scoring time make it advantageous to clinical practice if assessing rate of handwriting in isolation. This is rarely the case; therefore other instruments assessing both handwriting quality and rate will likely see more use.
Author/Others: Author (Wallen, Bonney, & Lennox, 1996a,b; Wallen & Mackay, 1999); others Usefulness: The HST was designed to provide an up-todate and objective means of evaluating the handwriting speed of students presenting with handwriting difficulties. The HST is a useful tool for determining the eligibility of students for extra time or other assistance in examinations, identifying children who require intervention for handwriting speed difficulty, evaluating the effect of intervention on handwriting, and conducting research with handwriting speed as a variable (Wallen et al., 1996b). Validated: On 1292 third through twelfth grade students from New South Wales, Australia schools with normative data determined after analysis. Content validity was established in development.
REFERENCES Wallen M, Bonney M, Lennox L (1996a). The handwriting speed test. Adelaide, Australia, Helios. Wallen M, Bonney M, Lennox L (1996b). Interrater reliability of the Handwriting Speed Test. Occupational Therapy Journal of Research, 16:280–287. Wallen M, Mackay S (1999). Test-retest, interrater, and intrarater reliability and construct validity of the Handwriting Speed Test in year 3 and year 6 students. Physical and Occupational Therapy in Pediatrics, 19:29–42.
Chapter
15
PRINCIPLES AND PRACTICES OF TEACHING HANDWRITING Mary Benbow
CHAPTER OUTLINE DEVELOPMENTAL EXPERIENCES THAT UNDERLIE SKILLED USE OF THE HANDS Upper Extremity Support Wrist and Hand Development Visual Control Bilateral Integration Spatial Analysis Kinesthesia Summary HANDWRITING TRAINING: PENCIL GRIP Tripod Grip and Alternative Grips Remediation of Pencil Grip KINESTHETIC APPROACH TO TEACHING HANDWRITING Cursive or Manuscript Writing Motor Patterns in Cursive Writing Why Teach Writing Kinesthetically? Kinesthetic Teaching Method Kinesthetic Remediation Techniques SUMMARY
The use of tools was a major breakthrough in human history, extending our ability to control our environment. The first tools were natural objects—sticks, stones, and bones—requiring gross motor skills such as pushing, striking, and throwing. It took thousands of years for humans to develop a tool as precise as a pen
or pencil, requiring intricate fine motor skills. Because the simplicity of a pencil often is taken for granted, it is easy to overlook the complexity of its operation. In the opinion of this author, a pencil is more difficult to use than the most powerful computer from a motor skills perspective. It is no wonder that children, their parents, and their teachers are often frustrated with the results of early experimentation with this advanced tool before the fine motor muscles are ready to function. Boys, whose fine motor development is typically behind that of girls (McGuinness, 1979), have greater difficulty managing writing tools and tend to prefer simpler motor tools, such as computer keyboards, Nintendo games, and TV remote controls. Girls face a different problem. Many of them begin to “write” as early as age 21/2, often without proper adult attention or supervision. Lacking sufficient hand development or guidance, they may adopt pencil grips that are inefficient or even harmful as they pursue their fascination with the letter shapes Big Bird shows them daily. The overall management of handwriting training can be conceived as a kind of triage, in which some children (group A) learn to write well regardless of the method(s) of teaching. At the other extreme a few (group C) are unable to learn the skill no matter what interventions are employed to alleviate their difficulties. Most children (group B) fall between the two extremes and readily benefit from efficient teaching strategies. Therefore group B should receive the greatest concentration of effort from teachers, occupational therapists, and other professionals. It is simple to distinguish between groups A and B, but much more difficult to separate group B from C. For this reason it seemed appropriate to develop teaching and treatment strategies around the combined needs of groups B and C. Appropriate compensatory or intervention strategies
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should enable most of these children to gain functional writing skill. In the current educational environment of “No Child Left Behind,” school departments require that children with widely different developmental levels be taught together in integrated classrooms; therefore handwriting instruction demands better investigation and more attention. Professionals must concentrate on related-skills necessary to ensure more consistent success with this high-level skill. They must teach all school children more efficiently, thoroughly, and permanently. All students, especially the great variety of children who are subtly delayed, can benefit from developmentally ordered physical, visual, kinesthetic, and fine motor experiences. A clearer understanding of the constellation of skills that enable one to write efficiently must guide professionals in developing more systematic ways to prepare children for handwriting, as well as to teach handwriting. Occupational therapists are frequently called on for motor evaluations, consultation, and remediation for public school children. Nonfunctional handwriting is the most common reason for referral. For an evaluation to be useful for effective curriculum implementation or intervention, professionals must understand the chain of motor skills that enable a student to write comfortably, automatically, and accurately. The purpose of this chapter is to describe hand skills that make children more adept at operating a pencil. This chapter presents not only the optimal skills for the way the hand should work to produce efficient handwriting, but also the problems that arise when motor components for the skill are absent or less dexterous motor patterns are used. Techniques to promote the development of the foundation skills are presented, along with remediation or compensation techniques for related problems that arise. The final section on the teaching and remediation of handwriting presents the rationale and method for the kinesthetically based instruction of cursive writing. It should be noted that this chapter does not address language components such as word finding, sentence formulation, punctuation, and spelling, but is limited to the mechanical aspects of writing and cognitive-associative mental processes. Handwriting instruction in American schools typically begins with manuscript writing (printing) and shifts to cursive writing in the third grade. The author’s experience has been that the development of functional handwriting can be fostered by an earlier introduction to cursive script. Therefore the discussions of prewriting and writing skills emphasize cursive writing. The cursive versus manuscript writing issue is discussed more fully in a later section of this chapter.
DEVELOPMENTAL EXPERIENCES THAT UNDERLIE SKILLED USE OF THE HANDS Since 1992 as fear about sudden infant death syndrome (SIDS) became widespread, the “Back to Sleep Campaign” was implemented to lower the risk of SIDS (SIDS Task Force). Many anxious parents misinterpreted this warning to mean their baby should never be prone, even during daytime play periods. While supine or semireclined in a variety of plastic “exoskeletons” infant seats, the baby can barely raise his or her head, much less bear weight on the upper extremities and elongate and strengthen the cervical spine. “Tummy Time” in prone posture facilitates head lifting and neck strengthening, trunk stability, and balance while weight bearing on the upper extremities. Therefore lack of prone positioning during the baby’s play periods lengthens the time it takes to master such basic skills as lifting and holding the head, pivoting, turning over, and sitting and crawling. Lack of weight bearing on the hands may affect hand structures; underdeveloped arch formation and stabilization, incomplete expansion of the thumb-index web space for full opposition, and skilled manipulation of tools. Skilled use of tools (e.g., silverware, scissors, pencils) often lags because of lack of full range of motion at the carpometacarpal (CMC) joint of the thumb. To be effective in promoting efficient graphic skills, developmental therapists must address these unresolved ergonomic factors (i.e., postural, tonal, stabilizing) in addition to fine motor intervention. Graphomotor production difficulties usually cluster under one or more of the following classifications: (a) incomplete range of motion and use of the proximal joints of the upper extremity, (b) immature wrist and hand development with clumsy distal manipulation skills, (c) insufficient experience in eye-hand control, (d) incomplete bilateral integration, (e) inadequate spatial analysis or synthesis skills, and (f) reduced somatosensory input with failure to develop kinesthesia.
U PPER EXTREMITY SUPPORT The interaction of all joints of the upper extremity— scapulothoracic, glenohumeral, elbow, and wrist—is required for the development of dexterous hand skills. Each component must be developed and move freely into its mature patterns. In children experiencing fine motor delays it is not uncommon to find the shoulder joint slightly biased toward internal rotation, adduction, or flexion; the elbow joint toward flexion or
Principles and Practices of Teaching Handwriting • 321 pronation; and the wrist toward flexion and ulnar deviation. In addition to fluid range of motion, each upper extremity joint must provide a stable base of support for the control of the joint(s) distal to it. When a therapist finds functional limitations in proximal joints, he or she should include weight bearing, traction, and compression activities for scapula, shoulder, and elbow joint control. Specific proximal joint needs are most naturally incorporated into therapeutic or adapted physical education goals. For example, jumping rope backward requires the simultaneous involvement of all upper extremity joints moving into their mature patterns. Because this activity fully incorporates all upper extremity joints, it should be included in developmental hand therapy programs for children who show dysfunction or inefficiency in proximal joints. A younger or less coordinated child should first learn to turn one end of a long rope with a partner using the dominant hand while a third child jumps. The initial goal is to develop external rotation in the shoulder on the dominant hand side followed by full range of motion in the opposite shoulder. The third step is for the child to swing a jump rope backward over his or her head and step behind it when he or she hears the rope strike the floor. Finally, the upper and lower body should be coordinated in reverse rope jumping. The case of Zachary demonstrates the value of an integrated upper extremity program for hand skill development. This 6-year-old boy was referred to occupational therapy for difficulties with printing and sloppy paperwork. Initially a program of hand activities was prescribed that specifically addressed the referral request. Zachary faithfully practiced his prescribed program. He made little progress because the hand activities felt so unnatural and were so difficult. Client resistance became a new and serious deterrent. After assessing his upper extremities more thoroughly, the therapist found some limitation of motion in external rotation of the shoulders and incomplete supination at the elbows. After a progressive program for upper extremity range and stability, his hand skills followed naturally and resistance to fine motor activities lessened. Zachary’s case is fairly typical. The often overlooked component of proximal development proved to be the key in unlocking distal skills.
WRIST AND HAND DEVELOPMENT In addition to a developmentally based gross motor program, early education curricula should stress developing the entire upper extremity with particular emphasis on the hands. The goals are listed in Box 15-1. The
BOX 15-1
Early Education Curricula Goals for Developing Upper Extremity and Hands
1. To stabilize the wrist with fine manipulation of small tools, objects, and writing implements 2. To open and stabilize the thumb-index web space 3. To increase and stabilize the arches of the hands 4. To separate the motor functions of the two sides of the hand 5. To develop two aspects of precision handling, precision translation and precision rotation
hand functions in Box 15-1 are fundamental for all higher-level tool skills.
Stabilize the Wrist Bunnell (1970) states that the wrist is the key joint of the hand. Wrist limitations cannot be compensated for by any other upper extremity joint. Because wrist movements are inseparable from the hand as a single physiologic unit, therapists should combine wrist and hand activities. The position of the wrist influences the tension of the extrinsic muscles. The origins of the extrinsic muscles of the hand are in the forearm and generally move the digits in gross flexion or extension patterns. Extrinsic tendon length does not allow simultaneous maximal flexion or extension of the wrist and fingers, so interplay is seen with wrist and finger movements. Long and co-workers (1970), using electromyography found that intrinsic muscles (whose origins are in the wrist and/or hand) guide and grade the multiple intermediate finger and thumb patterns and control all rotary movements of the thumb and metacarpophalangeal (MP) finger joints used in precision handling. Tubiana (1981) pointed out that no single articulation in the hand is an isolated mechanical entity. Instead, each articulation functions as part of a group arranged in kinetic chains. Each articulation depends on the equilibrium of forces acting at its level, and this equilibrium is subject to the position of the immediate proximal articulation. Mobile balance is realized through the interdependence among the elements along its osteoarticular chain. That interdependence includes both passive and active components. The active component is the dynamic balance between antagonistic muscles. The main passive component is the restraining action of ligaments and muscular viscoelasticity that facilitates coordination of motion (Smith, 1974). Therefore the wrist influences the position of the MP joint, and the MP joint influences the position of the proximal interphalangeal (PIP) joint, which in turn
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influences the distal interphalangeal (DIP) joint. These anatomic principles provide ways to analyze, design, and sequence hand activities that are more effective in developing the constellations of motor patterns for fine motor skills. A tool is an extension of the hand that uses it. Developmental logic dictates that a hand must be skilled before it can skillfully manipulate a tool as an extension of the hand. Activities that facilitate wrist stabilization in extension with precision finger skills can best be done on vertical surfaces above eye level. Such positioning automatically places the wrist into its optimal posture and facilitates abduction of the thumb to work distally with the fingertips. Working above eye level requires holding the arms at a level at which their weight strengthens the muscles and stabilizes the joints of the scapula and shoulder. Enjoyable proximal joint activities include painting on chalkboards with brushes dipped in water or more colorful tempera painting on paper at an easel. Many commercially available toys can be vertically positioned to develop wrist stabilization with distal finger skill. Magna Doodle, Etch-A-Sketch, pegboards, and eye-hook boards can all be fastened onto a wall, set in a chalk rail or on an easel ledge, and secured with an elastic cord if necessary. The important part of each activity is that it is performed above eye level.
Open and Stabilize the Thumb-Index Web Space Muscle tightness on the flexor side of the wrist limits range of motion into extension and reduces stabilization of the wrist for distal digital manipulation. The CMC joint located at the base of the thumb column should fully rotate so the thumb pulp can be pronated and positioned diametrically opposite each of the four finger pulps. Incomplete abduction and rotation at this mobile thumb joint result in a posture that cannot be well stabilized for distal manipulation (Kapandji, 1982). A fully expanded web space between the thumb and index finger allows dexterous digital manipulation leading to economy, variety, and convenience of movement because it requires minimum involvement of the upper extremity joints when moving a prehended object. Feedback from the intrinsic muscles regulates grip pressure on the shaft of the tool and provides ongoing kinesthetic feedback to the nervous system for rapid automatic correction of motor programs. When the hand is in a power grip with the fingers flexed, there is a reduction in the firing of lumbricals, so the hand loses much of its joint-balancing potential and proprioceptive guidance (Long et al., 1970).
the fixed junctures allows stability without rigidity (Tubiana, 1981). The mobile elements include the five digits and the peripheral metacarpals of the thumb and little finger. The mobile units of the thenar and hypothenar eminences cup or arch the hand, providing balanced isolated intrinsic activity within the hand. Manipulating Chinese balls within the palm of the hand is a rapid way to develop all three arches. The balls should fit well within the cupped hand so that the thumb can rotate them around within the hand. Instruct the child to rotate the balls by moving the thumb into the center of the palm (Fig. 15-1). Activity sheets with circles to fill or shapes to circle or outline before coloring can be designed for this purpose. Activities can be graded by decreasing the size of shapes as refinement of skill progresses distally. When sheets or coloring book pages are secured in a vertical orientation (fitted onto a vertically mounted clipboard or taped up on a wall or easel), the oblique arch of opposition can more easily manipulate the pencil or marker. The most refined use of finger control with crayons or markers is in outlining the shapes before coloring them. The diamond coloring sheet shown in Figure 15-2 requires dynamic finger skill to outline followed by static finger skill to color in the shapes. Primary school children are self-motivated to draw and practice numbers and letters on the chalkboard when their efforts on this surface yield satisfying results. For one nursery school child, working on a vertical surface magically transformed his clumsy attempts to color at the table into performances that delighted him and his teacher. It may be worth noting that the first products of human use of an advanced tool, in the cave paintings at Lascaux, France, are on a vertical surface at or above eye level, as are many of the petroglyphs made by Native Americans on the canyon walls of the southwestern United States. Without knowing why, these primitive tool users maximized shoulder stability,
Increase and Stabilize the Arches of the Hand The hand’s great adaptability depends on its fixed and mobile units. Fixed elements include the distal row of carpal bones and the central attached metacarpals to digits II and III. The small degree of movement at
Figure 15-1 Chinese balls to develop arches in the hand. (Available from OT Ideas, Inc., copyright Mary Benbow)
Principles and Practices of Teaching Handwriting • 323
Figure 15-3 Small hand scissors designed by author shown with small sponge gripped by the ulnar digits. (Available from OT Ideas, Inc., copyright Mary Benbow.)
Figure 15-2 Benbow.)
Diamond coloring sheet. (Copyright Mary
wrist and thumb postures, and visual and hand dexterity for their expressive needs. Today skilled artists rarely draw or paint on a horizontal surface.
Separate the Motor Functions of the Two Sides of the Hand Capener (1956) noted the coupling action of the two ulnar digits (IV and V), which function together in power grips and precision handling. In precision handling, when the ulnar digits are flexed against the palm, they provide stability to the MP arch while isolating control of the radial digits for manipulation with the thumb. Separation of the ulnar from the radial side of the hand counterbalances the MP arch for higher-level skills. Holding a heavier item, such as a teacup is achieved by abduction and extension of digits IV and V. The radial digits (II and III) can be isolated and stabilized from the arched posture to perform their function more securely with the opposed thumb. The proper handling of scissors requires the separation of the motor functions of the two sides of the hand. The ulnar digits should be flexed and stabilized against the palm. With the wrist stabilized in extension, the child should place the distal joints of the thumb and middle finger into the loops (oval loops stabilize easier). The loops should be small enough to enable the child to stabilize the handles at the DIP joints of the long finger and the IP joint of the thumb. The index finger should be placed against the shaft of the handle to support the scissors in a vertical position and help to close the blades. The ulnar digits (IV and V) should be flexed and pressed against the palm to add stability to the MP arch. If it is frustrating or difficult to remember to flex and stabilize digits IV and V, then have the child press a small flat sponge against the palm with the two ulnar digits, as shown in Figure 15-3. This motoric separation of the functions of the two sides of the hand
isolates control in the two radial digits to work in combination with the thumb. Initially a child should practice simply opening and closing the blades. After intended blade movements become rhythmic, introduce tiny straws (which take almost no control from the nondominant hand) to be cut into tiny segments. Advance to oak tag or old playing cards, and finally to paper, which requires the most skill. The nondominant hand must hold the paper taut enough for cutting without tearing.
Develop Two Aspects of Precision Handling: Precision Rotation and Precision Translation Precision handling requires full range of motion at the CMC joint of the thumb so its pulp can be flexed and placed diametrically opposite each of the finger pulps. From this stable position the multiple variations of the two precision handling skills, precision translation and precision rotation, should be developed and refined. Translation movements require that the thumb and index or the thumb, index, and middle fingers move in synchrony in a toward-the-palm or away-from-thepalm pattern (Long et al., 1970). Needle threading uses a translation-away pattern from the fully flexed translation-toward the palm. Pulling a thread through a needle is an example of translation toward the palmfinger pattern.* Writing in a cursive hand requires rapid alternation of toward and away translation patterns to produce letter strokes. Shifting a stiff piece of oak tag through the eye of a yarn needle with the wrists stabilized against each other is an effective way for an older child to practice, speed up, and observe translation movements with the skilled digits. Marks can be placed on the strip to indicate increased length of movement as skill improves (Fig. 15-4). *The term precision translation is used by Long and co-workers (1970) to describe the movement of an object toward and away from the palm while the grip on the object is maintained. The term has also been used to describe the shifting of a small object such as a piece of lint from the fingertips into the palm.
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Figure 15-4 Needle threading or translation movement activity. Work to increase distance and speed with the skilled digits. (Copyright Mary Benbow.)
Bead stringing is the classic preschool activity for developing speed and dexterity in the alternating use of translation patterns. However, children who most need to develop this skill often adopt an efficient substitute system. They place the bead over the lacing tip rather than inserting the tip through the bead. Eye-hook lacing boards prevent this skill substitution and provide a more motivating activity for young children (Fig. 15-5). Because children tend to be self-driven to stay with this lacing board activity, it is effective and efficient
in developing translation-toward and translation-away finger skills. Precision rotation skill is used when strength demand is low, in activities such as opening and closing loosened tube caps or jar lids, turning knobs, and turning over small objects for inspection. When a child substitutes less efficient forearm rotation for digital rotation, an evaluation for range of motion and stabilization of the thumb is indicated. The child must have functional range of motion at the CMC joint to position the thumb diametrically opposite the third digit. Snapping the fingers is a simple thumb-finger test for evaluation of range of motion at the CMC joint. When there is incomplete separation between the thumb and index metacarpals, physically expanding the web space by joint mobilization and progressive stretching may be indicated. Expansion of the joint-supporting structures often can bring the thumb CMC joint into a position in which it can be stabilized for distal manipulation with the index or index and middle fingers. A simple activity to promote precision rotation is rolling tiny balls (1/8-inch diameter) of clay or therapy putty between the pulps of the thumb and index finger. Another is playing tug-of-war with a small-diameter object such as a coffee stirrer or plastic lace. Digital rotation at the MP joints is necessary to shape the grip snugly enough so the extrinsic muscles can effectively provide strength for distal power pinch. Pinching a coffee stirrer or plastic lace between the index and thumb pulps enhances position contact of the finger pulps for strength. An engrossing group activity is turning over a row of 25 pennies from heads to tails in a race against classmates or a stopwatch. A tiny moving picture type flip-book or small deck of cards requires full CMC expansion in the hand of a primary school child. Adequate range and stability at the CMC joint are necessary for both card shuffling and distal dynamic pencil control. With middle school or high school– aged students, shuffling a standard size deck of cards is a challenging activity that promotes range of motion and stability at the thumb CMC joint. Tactile sensitivity of the thumb pulps needs to be refined to manage the intermixing of the cards from the two hands.
VISUAL CONTROL
Figure 15-5 Threading board designed by author. (Available from OT Ideas, Inc., copyright Mary Benbow.)
Manuscript and cursive writing use vision differently in the guidance of the pencil. In manuscript writing the hand’s output depends almost entirely upon the input and ongoing guidance of the visual system. In cursive writing the visual system should play a less significant role. For this reason many children with visual motor problems should be advanced to cursive instruction as
Principles and Practices of Teaching Handwriting • 325 along the middle of the yellow line. With the paper positioned on the desk top so that the lines run from top to bottom (slanted for better viewing), the child is instructed to draw the first line from top to bottom and the second line from bottom to top (Fig. 15-6). Accuracy of control is noted as the child visually guides the hand into upward and downward space. It is insightful to ask which direction was easier for him or her to complete. If the child appears stressed while doing the preceding task on a desk top, a second sheet can be taped on the wall or chalkboard in the vertical plane with the middle of the sheet of paper positioned at eye level as the child stands to work. This placement requires the child to elevate and lower the eyes along the two lines. If he or she does poorly on trial 1 (desk top) and better on trial 2 (wall or chalkboard), it will be advantageous for the child to stand while practicing numbers and letters on the chalkboard or at an easel. The child’s ability to control a pencil in these two directions is a clear demonstration of the visual system’s guidance of the hand for graphic skill training. Tracking comfort and skill often clarifies the reason some children are unable to conform to writing numbers and letters from top to bottom. Mature handwriting requires input from both foveal and ambient vision. Inadequate integration of the two visual systems is seen when the letters are fairly well formed but the writing is irregular in size and spacing and positioned poorly in relation to the writing line. Bottom to top
Numbers 1-10
Top to bottom
Name:
soon as written work is required. The reduced demand for visual motor integration yields more satisfactory results. When using kinesthetic teaching strategies for cursive training, visual control becomes secondary to proprioceptive guidance during the first lesson. An accomplished hand writer limits visual control to staying on the writing line, guiding retrace lines, properly spacing between words, and serving as a neatness checker of written work. Most American schoolchildren learn to print their names before entering kindergarten. A few children master the whole alphabet. Imitating family members, early education teachers, or educational television shows, they rely heavily on visual control in drawing their block letters. Close visual monitoring of the pencil point is necessary for them to control stroke length and angle, find the intersecting or joining points, and inhibit pencil movement at the intended stopping place. In any mainstreamed primary classroom one can observe many accommodations to insufficient eye-hand skills. A child who has difficulty focusing when eye alignment or extraocular control is deficient often adapts by turning the head far to one side to isolate use of one eye while diverting the other eye from the paper. The child has unconsciously discovered that this head position eliminates the second image. A child who has great difficulty lowering and converging the eyes continues to draw circles, write numbers and letters from bottom to top, and fails to adopt the cultural pattern of top to bottom stroking of letters and numbers. In the early grades figure copying tests such as the Developmental Test of Visual Motor Integration (Beery, 1997) are used to determine a child’s visual motor integration age level. Beery cites multiple developmental researchers who have explored the underlying visual motor skills that determine a child’s potential for mastering manuscript formations. Beery states that it is prudent to postpone formal pencil and paper writing until at least such time as a child can easily copy the VMI Oblique Cross. The oblique cross requires the child to cross the midline of the form using diagonal visual guidance. This high-level perceptual motor skill is necessary to produce 10 of the manuscript letters. An observation tool, the Observation of Visual Motor Orientation and Efficiency (Benbow, Hanft, & Marsh, 1992) can be a practical supplement to observe visual control of the hand as the eyes guide the pencil in upward and downward directions. To observe visual motor efficiency in these two orientations, the instructor should prepare an unlined sheet of paper (81/2 × 11 inches) with two lines 1/8-inch wide and 11 inches long. Lines should be drawn with a yellow highlighter and spaced about 2 inches apart. The child is directed to draw a continuous controlled line with his or her pencil
Figure 15-6 Form used to observe visual control of pencil. (Copyright Mary Benbow.)
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This is seen in manuscript within words, as well as between words. Spacing problems in cursive are usually limited to spaces between words. The ambient system is faulty in providing the spatial component as the hand produces proper formations. When poor efficiency in visual-motor orientation is noted in the classroom, a child should be further evaluated by a physical educator because ball and game skills are often impaired as well. Remediation for visual scanning problems is not to be found in paper and pencil activities but in vestibular-based visually demanding gross motor activities. If the child has difficulty tracking upward, include activities that require upward gaze such as tossing a ball straight up and catching it at chest level, gently tapping a ball suspended above eye level, racket games, volleyball, and flying kites or airplanes. Alternatively, if the child has difficulty tracking downward, bouncing a ball and catching it at waist level is advised. A line or pattern drawn on the floor or sidewalk can make bouncing on a Hippity-Hop ball or riding a scooter board or bicycle more interesting and organizing. Activities demanding rapid movement and visual guidance help integrate visual tracking with body skills. In cursive writing, problems in tracking downward result in poorer control of the loops that descend below the writing line (f, g, j, p, q, y, and z). Alternatively, when children are stressed by elevating their eyes, they may have more trouble controlling the upward moving ascender strokes of tall letters (h, k, b, f, l, and t). Suspect a near-point focusing insufficiency when a child can produce a single stroke but is inaccurate in retracing line segments. A therapist can detect a focusing problem most easily on the retraced segments of a, d, m, and t. When these visual motor errors are seen consistently, a referral for a visual examination is indicated.
BILATERAL I NTEGRATION Bilateral integration and sequencing (BIS) dysfunction is a common cause of motor delays or deficits (Ayres, 1991). In addition to well-documented gross motor deficits (e.g., postural, equilibrium, and body side coordination), a child with BIS dysfunction is slow to establish a good division of labor between the two hands. By the time most peers are performing well in the graphic motor area, the child is still using the hands interchangeably to do far less sophisticated activities. On paper and pencil tasks the child usually experiences an interruption in crossing the visual midline and produces reversals long after other classmates have resolved this issue. The child is unable to change stroke direction in a continuous flow pattern. This is evidenced as an inability to shift the right under-curving lead-in
stroke to the left when approaching the line top while writing letters k, b, f, and l. Functional graphic motor output remains far beyond the child’s reach. Unfortunately, additional paper and pencil practice does not solve these developmental issues. A child who is not bilaterally integrated neglects stabilizing the paper with the nondominant hand when writing or coloring. Until the dominant hand assumes a definite leadership role, the nondominant hand does not sense and perform its assisting role. Instead of cooperation between the two body sides, there is residual competition. Synkinesis (motor overflow) usually is observable, which supports the finding of inadequate central nervous system inhibition of the nondominant hand as the dominant hand is being programmed by the brain. When an older student must produce a lengthy written assignment, it is visually helpful to draw a pair of bold black margin lines about 1 inch from the left side of the paper. The high-contrast lines alert his or her peripheral vision and cue the child to stabilize the paper with the nondominant hand while maintaining left margin alignment. The nondominant hand positioned on the edge of the paper helps to visually define the writing area and promotes more balanced sitting posture. Directionality confusion is suspected when a child continues to write wraparound letters after instructions are given to stop at a specific point and retrace a letter segment. When this wraparound pattern, as seen in the letters a, d, g, q, and c, is the only immature pattern noted, one can logically assume that the motor behavior was generalized from self-taught incorrect formation of manuscript letters at an earlier stage. A typical example is seen in Figure 15-7. When a child with incomplete bilateral integration draws horizontal or diagonal lines, a hesitation or jerk is often seen along the pencil line in which the child’s eyes crossed their midline while guiding the pencil. This interruption is even more visible and disorganizing when the child draws diagonal lines. Typically the child produces near-vertical lines for diagonals without
Figure 15-7 Example of the incorrect formation of the wraparound letters a and g. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
Principles and Practices of Teaching Handwriting • 327
for
Figure 15-8
for
for
Typical reversal of capital cursive letters. (Copyright Mary Benbow.)
being aware of it. The child’s cursive writing appears to be near vertical as well. Vertical letters are more slowly produced because the wrist has to be repositioned to efficiently make the long diagonal down strokes. A later sign of a problem with bilateral integration is the writing of mirror-image letters or numerals. These output errors are more commonly seen when a symbol is produced in isolation. An evaluation of 900 middle school writing samples revealed that the most typical residual reversals of letters in cursive writing were limited to three left-moving capital letters: 3 for E, f for capital J, and horizontally expanded reversed lower case b for capital I (Fig. 15-8). Averting the gaze is an effective accommodation to writing letters that reverse directions abruptly across the visual midline. In writing capitals D, G, and S, the child should be taught the place to halt the pencil progression and shift visual focus. The focal place is usually where the stroke ends, as seen with directions for capital D in Figure 15-9. The child must avoid visually monitoring the pencil point where it recrosses the visual midline to write these letters successfully. An enigmatic problem associated with BIS dysfunction is seen in a child’s inability to change stroke direction in a continuous flow pattern. The child feels the need to touch the top of the line and pause before being able to shift line direction. When writing the long ascenders of the loop letters (h, k, b, f, and l), it is nearly impossible for these children to shift the flow of the right ascending lead-in stroke to the left while approaching the top of the line (Fig. 15-10). In these tall loop letters the change of direction is necessary to prepare for the immediate down stroke once the line top is touched. Changing directions in a continuous flow pattern proves to be an intractable writing problem. To develop this sense of direction flow, the child needs to bodily understand the verbal directions as demonstrated by the instructor. The shifting direction of the tall loop stroke is best taught through the shoulder while writing in the air. Stress the inhibition of the right ascending stroke where it shifts leftward and up to the top of the line. Only when the child
Figure 15-9 Special instructions given to children learning to write a capital D. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
Figure 15-10 Illustration of the problem in changing direction with a continuous flow pattern. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
can master air writing with the shift of direction should he or she attempt it on paper. Consistent repetition is necessary for kinesthetic success. The difficulty of changing stroke direction in a continuous flow pattern also causes a problem in producing the alternating swoop line used to top capital F and T.
SPATIAL ANALYSIS Children with non–language learning disabilities (NLD), which include difficulties with math, nonphonetic spelling, and visualizing, usually lack strategies to analyze geometric shapes, numbers, and letters. These children require detailed letter analysis help to learn to write. Small incremental steps (including starting place, pencil progression, distance and speed at which to move the pencil, and stopping point) must be examined and explained and re-examined and reexplained. Retraces, the point of intersection with leadin strokes, and instructions for the release stroke or
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connector unit require a great deal of emphasis and repetition. The instructor should point out and stress the similarities of letter forms within the letter groups or they will be missed. Visual and verbal images that give letters their identity are necessary to aid memory and cue the lead-in stroke. Children acquire functional writing more easily when they are speed coached. All motor learning requires that speed be matched to task difficulty and the learner’s level of skill. A therapist can reduce learning time and trial-and-error frustration by explaining where the child should move the pencil slowly and quickly (Benbow, 1990). To hasten developing this sensitivity for all students in the room, initial letter instructions should include speed tips: The lead-in strokes flow more naturally when done quickly; retraces require some visual guidance, so slowing down is advised; speed should be resumed for any single line segment or release stroke that follows. These instructions seem most logical and are usually understood and followed by most second graders. Speed coaching is helpful for children who are struggling with any type of gross or fine motor skill learning. NLD children can learn cursive writing with their peers when the entire class is given detailed visual and spatial analysis and verbal directions for writing each new letter. The relatively good language skills of NLD students should be called upon to support this motor learning. Subvocalizing the motor plan guides writing hand movements. This practice should be continued until the writing is faster than the verbalizing. Writing instructors should be precise in their use of the word “line.” It is confusing to the student to use the same word to describe top and bottom lines and the space between lines. Instructing the student to make a letter “half a line high” only adds to his or her confusion. If instructors consistently refer to the top line, writing line, and dotted middle marker, they will not confuse their students. The area between the lines should always be called a space (or half space for letters ascending only to the middle marker). It is also helpful to the child if the writing line is darker than the top line or colored for initial learning and practice sessions. Using the designations writing line, top line, and middle marker, the instructor can easily describe what space the letter should fill. For example, all lower case cursive letters lead in from the writing line and ascend to the middle marker or top line. Seven letters descend to the middle marker below the writing line. Only four letters occupy more than a whole space: lower case f, and capitals J, Y, and Z. Negative shapes are created between lines and letter strokes. If students are made aware of them, these negative shapes can aid in determining whether the letters are written correctly. For example, a triangle is
Figure 15-11 Showing negative shapes created between writing lines and letter strokes. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
created on the writing line by the lead-in stroke and the lower rounded segment of the letters a and d (Fig. 15-11). Contrasting it with the smaller triangle made on the right side of these letters before the release stroke proves to be an intriguing challenge to the novice for quality control. Readily identifiable negative shapes can help the child recognize letter accuracy and serve as a guide for self-correction. These visual cues control for line contact as well. Producing the small triangle at the bases of i, u, w, and t (Fig. 15-12) prevents releasing the down stroke too soon for a good connection or release unit.
KINESTHESIA Writing is a motor skill and, as with other motor skills, efficient writing depends on kinesthetic input. Motor skills developed kinesthetically, such as riding a bike, keyboarding, or handwriting, are most permanent. In writing, an internal sensitivity that a letter movement feels correct reduces a child’s need to visually monitor the fingers or pencil point while moving along the line. This security enhances speed in learning and confidence in cursive writing. Kinesthetic writing naturally accelerates over time to functional speed without the reduction of performance quality seen with visually guided writing. The visual system is far too slow and mechanical to monitor the serial chain of finger movements necessary for note taking much beyond mid third grade. Advising a child to slow down (allowing time to visually monitor the writing hand) temporarily results
Figure 15-12 Knowing that the triangle should be small prevents a premature release of the down stroke. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
Principles and Practices of Teaching Handwriting • 329 in more legible paperwork. However, this remedy fails in middle school and beyond, when greater speed is necessary in lecture settings. Therefore kinesthetic training is important whether or not a child has a visual motor or spatial problem. This is an area of training that should be explored and further developed by early educators. Kinesthetic skill development is most beneficial for children experiencing visual motor deficits. Kinesthesia is an effective compensation for eye-hand coordination difficulties and can be a powerful builder of motor confidence. Kinesthetic training enables these children to bypass their problem area and become efficient writers by concentrating on kinesthetic feedback. If diminished kinesthesia is not enhanced, a child continues an over-reliance on visual monitoring, with a subsequent slowness in the production of writing. Kinesthetic activities are an essential aspect of both prewriting and writing programs. Kinesthetic skills usually intrigue young children. Elementary kinesthetic activities can be done on desk tops, at the blackboard, or in the gymnasium. A sample for each location is demonstrated in Box 15-2. As noted, kinesthetic writing should use limited visual motor control. Shape-copying tests such as the Test of Visual Motor Integration are useful in predicting the child’s potential ease or difficulty in learning manuscript. Copy forms and manuscript letters require analysis and synthesis of the forms to duplicate them
BOX 15-2
Sample Elementary Kinesthetic Activities
1. Desk Top: Place an object (e.g., coin or cube) anywhere on the desk surface within the arc of the child’s reach. Withdraw the child’s hand to a resting position and ask him or her to close the eyes and reach directly to the object. Grade the activity by having the child place the object with one hand and retrieve it with the other. 2. Blackboard: Sports that have a spatial component (e.g., baseball diamond, golf green) can be sketched on the blackboard. After the child visually and motorically senses the size and shape of the display, have him or her close the eyes, visualize the display, and draw with chalk a run from home plate for a single, double, or home run (Fig. 15-13). 3. Gym: After gaining the feel of movement of pitching like objects into a container, have the child close his or her eyes and use kinesthetic sense to continue the activity. The child should not alter orientation or distance and the objects should be identical in weight and size. The most challenging position for this activity is seated on a one-legged stool.
2nd
3rd
1st
Home Plate Figure 15-13 Benbow.)
Chalkboard baseball. (Copyright Mary
accurately. Skill in this area is less helpful in predicting the ease a student will experience in learning cursive writing. A Production Consistency Sheet (Benbow et al., 1992) can be used to informally observe a child’s kinesthetic aptitude in repeating and spacing cursive letters in words using the kinesthetic sense. Model shapes are displayed in the upper left-hand comer of a half sheet of unlined paper (51/2 × 81/2 inches). Each model is 1/2 inch high. The models include a square, a circle, a triangle, and a cursive capital A. Instruct the students to duplicate the printed model using a fluid moving stroke(s) rather than a rigidly controlled stroke(s). The four shapes should be drawn in three evenly spaced rows of five figures. On completion of the fifteenth figure, the child is told to close the eyes or avert the gaze and complete a fourth row that looks like and is spaced like the rows above. The quality of the first three rows reveals the child’s visual motor control of horizontal, vertical, diagonal, or circular lines. The consistency of the fourth row is a graphic demonstration of the child’s kinesthetic learning potential for both configuring and spacing. The two examples selected in Figure 15-14 were drawn by 10-year-old boys who were classmates in a third-grade classroom. Consistency in shape, size, and spacing is a high indicator of potential for learning cursive writing. In comparing these two samples, one can predict that the child who drew Figure 15-14 A will learn to write with less difficulty than the child who drew Figure 15-14 B.
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TRIPOD G RIP AND ALTERNATIVE G RIPS A
B
Figure 15-14 Production consistency of an average writer (A) and a poor writer (B). (Copyright Mary Benbow.)
SUMMARY Children who benefit from ongoing diagnostic handwriting training usually have identifiable problems in one or more foundation skills. The first is gross and fine motor readiness for cursive instruction. Output or production problems can include difficulties with rapid sequential movements (often noted in the child’s early history as articulation problems), visual control, bilateral integration, and spatial analysis and synthesis. Feedback difficulties include inadequacies in visual and kinesthetic reafferent systems. Developmentally sequenced hand activities should be a major fine motor focus in preschools and early elementary education. Early educators should develop the full potential of children’s hands for all skills because the remediation of prewriting hand skills greatly facilitates the learning of graphic skills. The following sections turn to two specific aspects of handwriting training, pencil grip and kinesthetic writing.
HANDWRITING TRAINING: PENCIL GRIP Letter production skill can be influenced by the way the writer grips a writing tool. This section includes a
Handwriting is the most frequently used, complex, and lateralized skill used in education, yet little attention is paid to how, when, or where pencil practice best enhances the development of this skill. Adults should not assume that children somehow know the best way to hold a pencil or that they will acquire the ability through incidental experience. Rosenbloom and Horton (1971) found that 89 of 92 British children had developed a dynamic tripod pencil skill by 72 months, and Saida and Miyashita (1979) found that 151 of 154 Japanese children had developed this skill by 72 months. In 1986 this author found that only 33 of 68 American children of the same age used this grip. The other 35 children were managing in school with pencil grips that ranged from less efficient to maladroit. Any grip, efficient or inefficient, that has been used over time becomes kinesthetically “locked in.” An immature pencil grip that is kinesthetically locked in can inhibit a student’s ability to advance to a higher level even after hand development has progressed. Among 7-year-old typical children in a Boston suburb, more quadripod grips (four digits—three fingers and the thumb—on the pencil shaft) were found than tripod grips (three digits on the pencil shaft). This open thumb web alternative to the normal tripod grip most likely developed with premature use of pencils or low joint stability in the hand. The fourth finger on the shaft adds power for stroking, as well as a wider bridge for stabilizing the pencil shaft. Many quadripod grips do progress and become dynamic and fully functional. The two slight disadvantages of this grip are (a) reduction in pencil point excursion, and (b) reduced stability of the MP arch when the little finger is used alone rather than being functionally coupled with the ring finger. A few children assume an adapted tripod grip (Fig. 15-15) in which they stabilize their pencil within the narrower web space between the middle and index fingers. This is an effective adaptation when joint stability is insufficient for controlled mobility. All of the skilled muscles of the classic dynamic tripod manipulate the pencil, and the MP joint of the thumb receives little if any stress. This posture is the most readily accepted alternate grip when a child or adult is having motor or orthopedic writing problems. Joint stability in the hand depends on ligaments and fixed structures. Working with school children, one sees evidence that the functional use of the hand depends more on joint stability than joint mobility. Children adopt unique ways to make their hands work for them
Principles and Practices of Teaching Handwriting • 331
Figure 15-15 Benbow.)
Adapted tripod grip. (Copyright Mary
when they lack joint stability. If the MP joint of the thumb is unstable, the web space will collapse when the pulp of the thumb is used to stabilize a tool in the distal fingertips or against another digit. In this case the child will unknowingly substitute the two heads of the powerful adductor and the first dorsal interossei (internal thenar muscles) for the three more highly skilled external thenar muscles: abductor pollicis brevis, flexor pollicis brevis, and opponens. The substitution of the internal thenar muscles causes the thumb to supinate or rotate away from the posture to allow pulp to pulp opposition (Tubiana, 1984). When using a pen or pencil, the individual wraps the thumb over or tucks the thumb under the index finger to control the stroke. Either grip provides a distal point of stability with the challenge to devise a system to mobilize the pencil proximally. When the web space is closed snugly over the pencil shaft, the thumb MP joint support structures are stressed in an outward direction, and the proprioceptive feedback used to guide and grade fine motor muscles is reduced.
REMEDIATION OF PENCIL G RIP In the development of motor skills there is evidence of transfer between different forms of action. The precision grip once mastered and reliably used with a spoon or fork begins to be used in drawing with a pencil. Therefore the instructor or therapist should evaluate the use of silverware before attempting to alter more complex skills with marking or writing tools. Silverware requires only stabilization of the shaft within the tripod digits. A writing tool requires stabilization plus controlled mobilization. If the child uses an immature power grip on a spoon, the instructor should develop
this distal holding skill before advancing to writing tools. A number of prosthetic devices (Fig. 15-16) have been developed to help position the digits for efficient distal manipulation of writing tools. These devices are sculpted to position the distal aspects of the radial digits into an open thumb/index web posture. Providing writing tools with positioning grips when preschool children are first exploring pencil use is the most sensible and effective use of these devices. Early implementation of these devices should eliminate the struggle to correct the inefficient grip after it has been reinforced and kinesthetically locked in. Limited rotation within the index and long finger MP joints and lack of an active transverse arch pushes the fingertips distally beyond a pencil gripping device. Therapeutic techniques can increase the third degree of freedom (rotation) at the MP joint of the index fingers. Then a grip device can be an effective reminder to maintain the advanced posture. Reducing hyperflexion at the PIP joint or hyperextension at the DIP joint (Fig. 15-17) can be accomplished by taping or blocking PIP hyperflexion with a tape support. With smaller, weaker, and less experienced hands tape support is often an adequate support to the extensor system. The surgical tape Microfoam (3M, St Paul, MN) adds stability to the digit. Tactile input from the taped finger is significantly increased so any movement helps the child to sense where his or her fingers are in space. A 1/8-inch wide strip of Microfoam tape should be affixed to the middle dorsal aspect of the index finger while the digit is positioned in full extension. The distal end of the tape should be attached to the nail and continue proximally over the DIP, PIP, and MP joints to the mid-metacarpal level (Fig. 15-18). The tape should be adjusted to give the joint(s) stability without rigidity. Some children choose to use the tape when a large amount of written work is necessary, whereas others insist on wearing the tape most of the day. A newer device called a “Pencil Pal” (Fig. 15-19) is helpful in reducing “white knuckle” pain caused by hyperflexion at the PIP joint and hyperextension at the DIP joint. The ring device is worn on the index finger to provide a higher stabilizing point for the pencil. This shift in position of the shaft of the pencil reduces hyperextension or “white knuckle” pain at the DIP joint. The ability to stabilize the CMC and MP joints of the thumb is critical for tripod manipulation of objects and tools. The IP joint cannot be a controlled mover if the MP joint cannot provide a stable base of support. This stability-mobility problem renders the hand most dysfunctional, especially in the manipulation of coloring or writing tools. In younger children with short fingers the “Pencil Grip” or external taping of the
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Figure 15-16 Prosthetic writing devices. From left to right: Start Right, Solo, Stetro, and the Pencil Grip. (Copyright Mary Benbow.)
Principles and Practices of Teaching Handwriting • 333
Figure 15-17 Pencil grip, showing hyperextension of the distal interphalangeal joint and hyperflexion of the proximal interphalangeal joint. (Copyright Mary Benbow.)
Figure 15-19 Pencil Pal, which reduces the angle of pencil and DIP hyperextension. (Available from OT Ideas, Inc., copyright Mary Benbow.)
BOX 15-3
Hand Structures Necessary for Tool Stabilization with Distal Manipulation
1. An active metacarpophalangeal arch with three degrees of freedom (flexion-extension, abductionadduction, and rotation) at the metacarpal joints of the two radial digits. 2. Full range of motion at the carpometacarpal joint of the thumb. Full range is necessary to stabilize the open thumb/index web space. 3. Motoric separation of the two sides of the hand. The ulnar side remains inactive to provide stability and shift skill to the radial digits as they work opposite the thumb. 4. Joint stability. Instability is a most prevalent finding caused by lax ligaments. The writing hand may require outside stabilization. Figure 15-18 Illustration of positioning of Microfoam surgical tape on the back of the index finger to improve joint awareness and add joint stability. (Copyright Mary Benbow.)
posterior aspect of the thumb often is sufficient support to make the thumb functional. Taping techniques outlined for the index finger can be applied to the thumb. When the MP joint of the thumb is unstable because of lax ligaments, a neoprene splint can support and protect the joint while writing. Hand structures necessary for tool stabilization with distal manipulation are shown in Box 15-3.
An “index grip”—a forearm, wrist, and pencil grip adaptation to extreme laxity at the thumb MP joint—is illustrated in Figure 15-20. The forearm is maintained in mid-rotation between supination and pronation and is solidly stabilized on the writing surface. The pencil shaft is cradled into the flexed index IP joints and extends distally across the third, fourth, and occasionally the fifth fingertips. The lead end of the pencil is pointed toward the writer’s midline. Writing strokes come from a combination of wrist flexion and MP finger extension with minimal thumb IP flexion. Because the writer does not progressively slide the solidly
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Figure 15-20 Index grip adaptation to extreme laxity of the metacarpal-phalangeal joint of the thumb. (Copyright Mary Benbow.)
stabilized forearm while writing, there is a need for the interplay between thumb IP hyperextension and wrist flexion. Writing into right space requires increasing flexion at the thumb IP joint and hyperextension at the wrist. When the wrist is fully hyperextended, a major right shift of the forearm is necessary for the next position from which to write additional letters or words. Because this “index grip” remains so nonfunctional over time, it is prudent to intervene as early as possible. Generally, when the joint support structures and extrinsic tendons cannot provide stability with the added support of the tape, the therapist should explore the use of a soft neoprene thumb abduction splint. This short glove-type splint positions the thumb in abduction and provides stability at the hypermobile MP joint when the thumb tip is positioned on the pencil shaft (Fig. 15-21). Neoprene provides stability without the
Figure 15-21 Neoprene thumb abduction splints. (Available from Benik Corp., www.benik.com; McKie, www.mckiesplints.com; copyright Mary Benbow.)
Principles and Practices of Teaching Handwriting • 335 rigidity of a thermoplastic device. Wrist-length neoprene gloves designed to provide thumb positioning and stabilizing are commercially available in appealing colors and multiple sizes. School therapists, knowledgeable in developmental hand functions, must use professional judgment to determine if, how, and when adaptations, motor interventions, or outside stabilization will benefit the child. The expectations of the child, teacher, and parents must be fully appreciated and honestly incorporated into the child’s educational plan. The therapist should include recommendations for short-term trials and offer periodic reassessments of their acceptability and effectiveness. Before intervening with an older student with an inefficient grip, it is critical for the child to understand why it is worth the effort to change. Pencil postures that are not held within the pulps of the digits do not lead to economy, convenience, or adequate feedback for the proximal-distal axis. The simple flexor or extensor synergy produces the fast writing needed once output demand increases in middle school. An adducted or closed web grip diminishes the proprioceptive feedback from the lumbricales of the skilled digits. The luxury of the unconscious regulation of pressure of the shaft of the pencil or the downward pressure exerted against the writing surface will be reduced or lost. Without this feedback, the student needs to stop and release the grip on the pencil to shake the pain out of his or her fingers. In addition, the child should be aware that a hypermobile closed web grip predisposes the joint to injury because of sustained co-contraction (Pascarelli & Quilter, 1994). The sequence demonstrated in Box 15-4 can make the transition to a functional distal grip more successful and less stressful. Many persistent persons write satisfactorily with poor grips. Many of these grips require the person to develop skilled use of proximal joints, which lack the precise control and speed of the distal joints. A pencil held in a closed web grip by the adductor pollicis cannot move far or use the rotary agility of the index MP joint in producing rounded strokes. Curving and rounding must be produced by more proximal joints requiring supination at the elbow and external or internal rotation at the shoulder. Wrist and forearm extensors must produce elongation of upstrokes, which is efficiently done using a digital translation away pattern and minimal wrist extension. A few writers use the entire skilled side (radial) of the hand to clutch and stabilize the pencil, and mobilize the pencil by extending and flexing the three joints of the power digits IV and V. Writer’s cramps are often seen in people who overuse their wrist in writing.
BOX 15-4
Making the Transition to a Functional Distal Grip More Successful and Less Stressful
1. The instructor demonstrates placement of the pencil positioned between the index and long fingers to make large random patterns using only shoulder and elbow movements. 2. The child imitates the pencil position and makes large free flowing movements following this rigid rule: No finger movements!! No letters!! No numbers!! 3. After the child accommodates to the feel of the pencil in the index/middle finger web space, the child should draw anything he or she pleases. 4. Once the child is at ease with the new pencil position, he or she should be encouraged to write large isolated numbers and letters. 5. When the new grip becomes annoying, the child should temporarily shift back to the former grip. 6. As soon as he or she feels ready, the child should return to the adapted grip. 7. When a child is in control of the alternating time shifting scheme, and experiences comfort and success, he or she tends to use the adapted grip more consistently.
KINESTHETIC APPROACH TO TEACHING HANDWRITING C URSIVE OR MANUSCRIPT WRITING One of the difficulties facing anyone investigating handwriting teaching and remediation issues is the lack of longitudinal studies in the field. Studies of preparatory skills, curriculum techniques, and timetables for the consolidation of writing skill at an automatic level are scarce. Tradition rather than scientific investigation has guided the teaching of handwriting in America. For example, there are no studies to substantiate the practice of using manuscript throughout kindergarten and first and second grade. In fact there is considerable evidence showing that such teaching may impede the development of functional handwriting in some students. Cursive instruction typically is introduced at the beginning of grade 3 in most American school systems. Several motor patterns adopted for printing and reinforced by 3 to 5 years of use are often resistant to change at age 8. In manuscript, children become accustomed to having the paper square to the edge of the desk in order to “write.” Later, slanting the paper to the appropriate angle to accommodate the wrist for diagonal down and up stroking in cursive is motorically
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disconcerting for many children. The D’Nealian manuscript program is unique in that letters are practiced with the paper positioned at an angle to take advantage of the wrist flexors in down stroking. Interestingly, this angling of the paper is beneficial only when the radial side of the hand is used to guide the pencil to write. However, this placement of the paper is usually demanded of all children regardless of grip. In addition, the eye-hand pattern of top to bottom control of vertical strokes needs to be shifted to bottom to top under curving diagonals. The strategy for gaining an understanding of ball and stick manuscript letters requires whole-to-part analysis followed by synthesis of the parts back into wholes. For many children it is perplexing to alter the process and analyze and integrate movement for the whole letter formation necessary for cursive writing. Again the D’Nealian manuscript program has been the most successful in reducing segmentation of lines for letter formations. In more than 30 years of experience in the teaching of handwriting, this author has found that second grade is an optimal time for most children to learn cursive handwriting. Student interest is high, and generally students have not yet developed faulty habits of inventive cursive before formal instruction begins. Training activities of combining letters into simple twoand three-letter words to practice letter formations and connector units are at a more appropriate cognitive level for second-grade students. Initiating cursive writing instruction in the fall of second grade allows a full year for students to stabilize this motor learning before the higher volume of written work is demanded at the third-grade level. Curricula that use instructional techniques to accommodate for perceptual and motor delays and deficits should enable nearly all children to advance to cursive writing at an earlier age. In schools in which cursive writing is introduced earlier and mastered kinesthetically, there is less confusion with and substitution of manuscript letters with cursive letters. Programming ample time to master cursive writing reduces the number of children who revert to manuscript in middle school when the output volume increases dramatically. The most perplexing problem for parents, teachers, and students themselves is how the student can have excellent fine motor skills and horrible handwriting. Levine (2003) explains that fine motor skills mainly recruit the fingers to manage artwork, origami, or airplane models, which are all navigated by the eyes. Graphomotor functions take place over different neural pathways and require rapid sequential movements guided by ongoing sensory feedback from the digits. The eyes are far too slow to monitor the movement of the digits as they move at a functional speed. Levine’s
findings on the importance of sequential finger speed to handwriting are supported by other handwriting researchers. Berninger and Rutberg (1992) evaluated children in grades 1 to 3 using six finger tasks; two displacement items, lifting and spreading, finger recognition, finger localization, repeated tapping of thumb pad to index pad, and rapid sequential touching of the thumb pulps to the four finger pulps (5, 4, 3, 2, 5, 4, etc., a measure of motor planning and rapid sequential movements). The rapid, sequential touching to all four finger pulps proved to be the only task that was reliable and valid for assessing handwriting skill in young children. Deuel (1995) found slow finger-tapping speed to be significant in her dysgraphic subjects with motor clumsiness. This was not significant in the language or spatial problem students. In isolated cases, when finger speed is significantly slow and sensory feedback from the digits cannot be reinforced by taping, refining printing skill may be the prudent solution to the student’s needs. Early and thorough teaching of keyboarding skills should be initiated as soon as practical in these cases.
MOTOR PATTERNS IN C URSIVE WRITING Motor output for cursive writing requires continuous stroke patterns. For this reason cursive letter analysis and instructions should be programmed to maximize visualization of the whole. Mental formulation of the plan with verbalization of the entire motor sequence should be stressed. This elicits the child’s proprioceptive and kinesthetic sense, supporting the flow of the whole letter. Most published handwriting programs currently in use employ a “copy-the-letter” scheme followed by visually guided reproduction of the letter within divided lines. Able or not, children are typically expected to convert to cursive writing during the fall of third grade. Many curricula introduce one or two alphabetically sequenced lower case letters each week. Such slow progression means that the lower case letters are unavailable for classroom work for 3 or 4 months, and the upper case letters still remain to be learned. Other programs introduce the lower case and upper case of the same letter in tandem. Shifting the unrelated motor patterns for lead-in strokes that are necessary when either alphabetical system is followed does not facilitate efficient motor learning. Grouping letters according to common movement patterns reduces memory demands and motor difficulties. After the initial session of introducing the movement pattern, during which each child learns to verbalize the pattern and produce it motorically, additional letters in the group can be learned expedi-
Principles and Practices of Teaching Handwriting • 337 tiously. The learning process is further hastened by reinforcement as all of the letters within the cluster are practiced together. General instructions included in most handwriting manuals are inadequate for children experiencing visual motor difficulties, incomplete bilateral integration, weak spatial analyzing ability, and attention or memory problems. Specific compensations for their special needs must be included with initial classroom instructions or their classroom practice periods will not be productive. In many schools the practice time is insufficient for all but the most skilled students to achieve functional output. Children are as frustrated by their handwriting failures as are their parents and teachers. Those with special needs, along with many who have simply not received enough help or time to master this complex motor task, resign themselves to poor handwriting or simply revert to manuscript, which received far more teaching time and reinforcement in the lower grades.
or setting of motor and memory engrams at an automatic level. The product of visually guided, or drawn, writing may be legible or even beautiful but is not functional because its methodical execution is too slow and consuming of cognitive power. The motor activity of writing must be fairly autonomous to free cognitive power for composing and spelling. The human nervous system can focus clearly on only one complex mental task at a time. Related skills, such as writing, must be sufficiently automatic to be carried out at an associative skill level. It is beyond the ability of most persons to compose a complex sentence and think about the way each letter in each word is executed. This failure in skill mastery is often the cause of a typical parent or teacher complaint: “My brilliant child’s hand cannot keep pace with his mind.”
WHY TEACH WRITING KINESTHETICALLY?
Handwriting is a lateralized motor skill of the highest order. When kinesthetic teaching techniques are incorporated from the beginning of handwriting instruction, the child naturally develops a kinesthetic potential for writing and other fine motor skills as well. The kinesthetic method of teaching cursive writing presented in Loops and Other Groups (Benbow, 1990) provides both general and compensatory instructions that are necessary for teaching in a mainstreamed classroom. It enables learning-disabled students to progress with their normal peers. Compensatory instructions and tips are included for students with perceptual-motor delays or deficits including difficulty with visually producing diagonals, midline crossing interruptions, and fluctuating motor memory for configurations. The group names for letters relate to familiar objects in a child’s environment and promote visualization of the lead-in strokes (Fig. 15-22). The first letter in each of the four groups must be mastered at the kinesthetic level before the child is allowed to advance to the next letter. As soon as any letter is mastered, instructions are given for connecting it to itself or other previously learned letters. The student’s awareness of and repetition of the common motor patterns within each group hasten mastery of the skill by reinforcing motor learning of the entire group. The author has conducted successful kinesthetic writing programs by dividing the learning of lower case letters into six teaching blocks for classroom use. The blocks are rapidly but thoroughly taught in daily 30-minute sessions in 6 weeks during September and October of second grade. The lower case letters are consistently reinforced with daily practice and used whenever possible (e.g., spelling tests when children have learned the necessary letters) to reinforce and
Writing is a motor skill that requires competent motor teaching and thoroughly reinforced motor learning. Fitts (1964) believed the process of skill acquisition falls into three stages. The first, the cognitive stage, involves the initial encoding of the instructions for a skill into a form sufficient for the learner to generate the behavior to some crude approximation. He emphasized that rehearsal of information is necessary for the execution of skill. The second, the associative stage, involves smoothing out of the motor performance with gradual detection and elimination of errors and the dropping of verbal mediation. The third, the autonomous stage, is one of gradual improvement that may continue indefinitely. One should distinguish these motor skill requirements for writing from other classroom learning. Learning to write is different from learning to read. If it were not, more good readers would be able to write legibly. Learning to write is not a language skill, although language skills are necessary to supply the content of written production. Learning to write should not be coupled with learning the alphabet. Learning to write letters in alphabetical order is more likely to enhance alphabetizing skills than handwriting skills. As with all fine motor skills, a student must accept the fact that the head learns to write faster than the hand. By its nature a kinesthetic approach to handwriting provides children with a clear, enjoyable progression from (a) the placement of the letter within the three half-space vertical units, to (b) the precise motor analysis with verbal support of the motor plan, to (c) the appropriate variations in speed, to (d) the practice with eyes closed or averted, and finally to (e) the reinforcing
KINESTHETIC TEACHING M ETHOD
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Clock Climbers
Kite Strings
Loop Group
Hills and Valleys
Figure 15-22 Letter group named to assist memory in learning. (Copyright Mary Benbow.)
stabilize this new skill. It is estimated that 95% of the letters on a page of writing are lower case, so stress is put on mastery to the automatic level to ensure functional writing speed. During the fall, manuscript capitals are used in combination with lower case cursive letters for all written assignments. Cursive capitals are introduced after the winter holiday vacation. This interval allows time for lower case to become stabilized before the capitals are introduced. This interim significantly reduces upper case and lower case confusion in children with weak memory for configuration.
KINESTHETIC REMEDIATION TECHNIQUES Writing errors often tend to cluster and make a paper look sloppy. With older students, correcting one or two cluster errors is effective in producing an acceptablelooking paper. Overall appearance often can be significantly improved by improving one or two problem areas. The three common cluster errors include the seven drop-loop letters (f, g, j, p, q, y, and z), whose loops are often huge, carelessly formed “sausages” that interfere with the lower line of writing. The second cluster is incomplete closure of the four round-overthe-top letters in the “a” or clock climber group (a, d, g, and q). The third cluster is failure to retrace letters to the writing line before the release or connector stroke. This failure places the connector unit too high or too low to lead into the letter that follows it. Cluster remediation often is more palatable for older students to undertake. Group letter analysis and speed coaching for segments to be produced quickly or slowly offers new hope that is motivating for these often discouraged students. With kinesthetic training, reinforcement, and moderate persistence most students
are self-motivated to improve their output quality and increase their writing quantity as well. Rule of the line or space between the writing and top line should be compatible with the fineness or bluntness of the writing pencil, pen or marker, and distal digital excursion of the writing tool—not the grade, age, or height of the writer. Line space of 1/2 inch or more naturally elicits movement from more proximal, less skilled joints. Regardless of age, when fine motor muscles are to be trained for graphic skills, the letter, number, or symbol size to be learned must be within the excursion distance of the digits that manipulate the pencil. A distal control sheet (Fig. 15-23) can be used to determine the ideal line rule for older students. Accurate stroke excursion flows more naturally and shows better control when producing strokes within a compatibly ruled paper. Most learning disabled students and children with “fixed” grips produce their best writing on 1/4-inch ruled paper. This narrower ruled paper feels comfortable for their motor system. An efficient way for the evaluator to detect wellformed letters that have not been learned to the automatic level is to look for connector breaks in the line at the point where the lead-in stroke is initiated. Figure 15-24 shows breaks in writing the alphabet before the letters f, j, r, and s. These breaks generally slow the writer’s overall speed. The interruptions, or “think breaks,” can also be detected within words, but a connected cursive alphabet is the most thorough and efficient way to assess the letters of the alphabet. Specifically reinforcing the identified letters that follow “think breaks” to the automatic level can often convert nonfunctional output speed into functional skill. Kinesthetic reinforcement of letters can increase writing speed while maintaining quality in a child who writes beautifully but has not developed functional speed. After carefully re-examining the line progression of any known letter and producing it with visual guidance, the child should close his or her eyes, visualize the letter, and write with fluidity on scrap paper 15 times before checking the results. Once the initial letter within a motor group is written reliably at an efficient speed, the remaining letters of the group should be brought up to speed one by one. A most popular time to suggest for children to increase their speed in writing is while watching television. The combination of these two activities diverts visual monitoring from the writing hand, and the student willingly extends practice periods.
Seating Posture and Classroom Arrangement Properly fitted furniture is indispensable if children are to learn handwriting efficiently. If the chairs are too high and the child’s heels do not touch the floor, he or she will be unable to counterbalance for weight shift as
Principles and Practices of Teaching Handwriting • 339
Figure 15-23 Practice sheet for distal finger control. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
Figure 15-24
“Think breaks” in writing. (Copyright Mary Benbow.)
the arm moves across the paper. If the desk surface is too high, the upper arm will be abducted too far to control the fingers effectively. Figure 15-25 illustrates a properly fitted student chair and desk for writing. The child’s desk should face the chalkboard where the teacher demonstrates the letters. There may be subjects that can best be learned in cluster or circular seating, but handwriting is not one of them.
Presentation of a Model The instructor introduces the letter by producing about a 15-inch model of it within the appropriate line space(s) on the chalkboard. While demonstrating each new letter, the instructor should recite each step of the motor plan. Familiar objects in the student’s environment are used to aid the students in visualizing the movement pattern as they motorically produce the
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Part III • Therapeutic Intervention while verbalizing the motor plan. With a few additional minutes of coaching, the students can be brought to a base level of skill before pencil and paper are introduced.
Paper and Pencil
Figure 15-25 Correct sitting posture for handwriting. Knees and hips are flexed at 90 degrees and feet are flat on the floor. The writing surface is 2 inches above the student’s bent elbow. The top of the chair should be slightly below the student’s shoulder blade. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
stroke progression. For example, the lead-in stroke for the letter “a” should climb up and round over an imaginary clock face between the 11 and 1 o’clock positions and stop. The line reverses by retracing this lead-in to 9 o’clock (Fig. 15-26).
Preparatory Exercises Before using pencils and paper, children perform two exercises. In each exercise they are to use the hand posture shown in Figure 15-27. Digits II and III are extended. Digits IV and V are flexed and held down with the thumb to reinforce separation of the two sides of the hand. For each exercise and each practice trial, verbal directions should be voiced by the teacher and the students. The students should use the shoulder movements and hand postures described previously to trace the letter in the air. Simultaneously each student verbalizes the motor plan while following the shape of the chalkboard model. Each student in the class must demonstrate the ability to verbalize the motor plan while following the line of the letter model. When secure in an understanding of the motor sequence, each student closes the eyes and pictures the letter to facilitate visualization of the movement pattern. During the second exercise, students place their elbows on the desk top to “write” using elbow and wrist movements. Again, they must recite the motor plan as they move their hands to pattern the visualized letter. These preparatory exercises are important to the initial learning of handwriting. The instructor is able to determine which children are unable to visualize the letter with eyes closed or averted from the model letter
Half-inch lined paper with a dotted middle marker is most satisfactory for early cursive practice with visual guidance. Paper folded lengthwise in 4- or 5-inch strips keeps the practice closer to the child’s midline where he or she has the most control. Using the newly learned motor plan, children complete 10 trials of the letter. They are told to “talk to your hand, and make it do what you tell it to do.” One should instruct children to subvocalize the motor plan as they form each letter. The instructor should be sure that the letter occupies the proper space(s) in relation to the writing line and middle marker. After 10 trials, each student should circle all of the letters that are correct. Among those circled they should select the one that is the best. After it is approved by the instructor, they should write 20 more from their own kinesthetic model. When all children are confident in their ability to write the letter with eyes open, they should close the eyes to visualize and gain the feel of the smaller movement pattern. Children who have tracking, converging, or crossing the midline visual disorganization should spend a major portion of their practice time with their eyes closed or gaze averted to avoid visual interference.
SUMMARY Kinesthetic handwriting training takes the drudgery out of a task that is often difficult and time-consuming. For all children and for their teachers, this provides some benefit. For some children, kinesthetic training is the single most effective tool for learning handwriting. Children who benefit the most from kinesthetic handwriting training usually have identifiable problems in one or more general areas. Developmental gross and fine motor foundation skills for cursive instruction may be less than optimal. Output or production problems may include difficulties with visual motor control. Kinesthesia is the key to the lost science of handwriting. Properly understood, it is the basis for understanding handwriting problems and for preventing or remediating them. Kinesthesia can be a curse or a blessing. When a complex motor activity is scientifically analyzed, appropriate foundation skills are set, teaching steps are properly sequenced, and the skill is practiced to the automatic level of performance, kinesthesia is a lifelong blessing in the performance of that skill. On the other hand, maladaptive kinesthetic patterns can be
Principles and Practices of Teaching Handwriting • 341 Clock Climbers
Figure 15-26 Practice sheet for clock climber group (a, d, g, q, c). (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
a curse. When a motor activity is haphazardly acquired at an immature stage of development and reinforced to the automatic level of performance, the kinesthetic pattern can last a lifetime, blocking effective and efficient performance of the skill and frustrating any attempts to modify it. One of the world’s great artists, Henri Matisse, once confirmed the importance of kinesthetic learning (Bernier, 1991). A friend who visited him noticed a sketch in white chalk on the back of his living room door. Matisse explained, Figure 15-27 Hand posture used in preparatory exercises. (From Loops and other groups: A kinesthetic writing system. Copyright 1990 by Harcourt Assessment, Inc. Reproduced with permission. All rights reserved.)
“I had been working all morning [drawing] from the model. I wanted to know if I had it in my fingers, so I had myself blindfolded, and I walked to the door and drew” (p. 30).
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The process that worked for Matisse is precisely the kinesthetic learning that is most effective for training children in handwriting. In cursive handwriting, as in drawing from a model, if I don’t have it “in my fingers” my work will be slow, crude, and unsightly. This approach allows children to discover what the great artist described.
REFERENCES American Academy of Pediatrics Task Force on Infant Sleep Position and SIDS (2000). Changing concepts of sudden infant death syndrome: Implications for infant sleeping environment and sleep position. Pediatrics, 105:650–656. Ayres AJ (1991). Sensory integration and praxis tests. In AG Fisher, EA Murray, AC Bundy, editors: Sensory integration, theory and practice. Philadelphia, FA Davis. Beery KE (1997). Developmental test of visual motor integration, VMI-4. Los Angeles, Psychological Corporation. Benbow M (1990). Loops and other groups: A kinesthetic writing system. Tucson, AZ, Therapy Skill Builders, a division of Communication Skill Builders, Inc. Benbow M, Hanft B, Marsh D (1992). Handwriting in the classroom: Improving written communication. The American Occupational Therapy Association Self Study Series. Rockville, MD, The American Occupational Therapy Association Press. Bernier R (1991). Matisse, Picasso, Miro: As I knew them. New York, Alfred A. Knopf. Berninger V, Rutberg J (1992). Relationship of finger speed to beginning writing. Developmental Medicine and Child Neurology, 34:198–215.
Bunnell S (1970). Surgery of the hand, 5th ed. Philadelphia, JB Lippincott. Capener N (1956). The hand in surgery. Journal of Bone and Joint Surgery, 38B(I):128–140. Deuel R (1995). Developmental dysgraphia and motor skills disorders. Journal of Child Neurology, 1(10):S6–S8. Fitts PM (1964). Perceptual motor skill learning. In AW Melton, editor: Categories of human learning. New York, Academic Press. Kapandji IA (1982). The physiology of the joints. New York, Churchill Livingstone. Levine M (2003). The myth of laziness. New York, Simon & Schuster. Long C, Conrad MS, Hall EA, Furler MS (1970). Intrinsicextrinsic muscle control of the hand in power and precision handling. Journal of Bone and Joint Surgery, 52A:853–867. McGuinness D (1979). How schools discriminate against boys. Human Nature, Feb:82–88. Pascarelli E, Quilter D (1994). Repetitive strain injury. New York, Wiley. Rosenbloom L, Horton ME (1971). The maturation of fine prehension in young children. Developmental Medicine and Child Neurology, 13:3–8. Saida Y, Miyashita M (1979). Development of fine motor skill in children: Manipulation of a pencil in young children. Journal of Human Movement Studies, 5:104–113. Smith RJ (1974). Balance and kinetics of the fingers under normal and pathological conditions. Clinical Orthopaedics and Related Research, 104:92–111. Tubiana R (1981). The hand, vol. 1. Philadelphia, WB Saunders. Tubiana R (1984). Examination of the hand & upper limb. Philadelphia, WB Saunders.
Chapter
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UPPER EXTREMITY INTERVENTION IN CEREBRAL PALSY: A NEURODEVELOPMENTAL APPROACH Laura K. Vogtle
CHAPTER OUTLINE
THE ASSESSMENT PROCESS Physical Status of the Individual
CEREBRAL PALSY
TREATMENT PLANNING
THE NEURODEVELOPMENTAL TREATMENT APPROACH AND PEDIATRIC THERAPY
THE INTERVENTION PROCESS
ROLE OF PERFORMANCE COMPONENTS ON OCCUPATIONAL PERFORMANCE
Efficacy of Neurodevelopmental Treatment
Neurodevelopmental Treatment and Hand Function
THE RELATIONSHIP OF POSTURE TO UPPER EXTREMITY FUNCTION
SUMMARY
Postural Control in Typically Developing Children
CASE STUDY TWO: A CHILD WITH LOW TONE
Postural Control and Anticipatory Control in Children with Cerebral Palsy SENSATION AND ANTICIPATORY CONTROL IN HAND FUNCTION KINESIOLOGIC ASPECTS OF TRUNK AND ARM FUNCTION Typical Trunk and Upper Limb Interactions Base of Support and Upper Limb Function BIOMECHANICAL INTERACTIONS OF THE UPPER LIMB IN CEREBRAL PALSY Contrasts between Hypotonia and Hypertonia TREATMENT APPROACHES: CONCEPTS OF INHIBITION AND FACILITATION Inhibitory Techniques Facilitation Techniques Combining Inhibition and Facilitation
CASE STUDY ONE: A CHILD WITH CEREBRAL PALSY
Therapists who treat children with developmental delays, movement disorders, and tone abnormalities such as those seen in cerebral palsy (CP) face significant challenges in their efforts to provide efficacious interventions. Muscle tone and spasticity are impairments seen in CP resulting from central nervous system (CNS) damage that cannot be permanently changed by means other than medication and surgery. However, therapists can maintain and improve performance in children with CP through their interventions and the use of assistive technology. Clinicians can influence client factors and modify environments that affect the manifestation of muscle tone, its power, and the degree to which it interferes with participation in occupation, thus adding to the potential for client participation. This chapter discusses the therapeutic management of children with CP, focusing on the use of neurodevelopmental treatment (NDT) as an intervention.
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CEREBRAL PALSY Cerebral palsy is a general term that describes a nonprogressive group of posture and movement disorders diagnosed within the first 2 to 3 years of life (Koman, Smith, & Shilt, 2004). The apparent causes of CP come from a variety of sources, including maternal infection, prematurity, multiple births, hypoxia associated with birth trauma, and maternal bleeding from premature placental separation, to mention a few (Nelson & Grether, 1999). Although the insult to the CNS is believed to be static, impairments seen with CP include musculoskeletal concerns, muscle weakness, spasticity, vision problems, cognitive limitations, and seizures. Secondary conditions related to the various primary impairments continue to evolve across the life span and include muscle tightness and contracture, joint abnormalities such as dysplasia and dislocation, growth problems, pain, social isolation, and diminished ability to participate in the community through occupations such as education, work, and leisure. Evidence suggests that loss of function seen in typical aging is accelerated in CP, and that the secondary conditions associated with CP become more common and more severe with age (Andersson & Mattsson, 2001; Cathels & Reddihough, 1993; Murphy, Molnar, & Lankasky, 2000; Turk et al., 1997). The incidence of CP over the last 20 years, currently estimated at 2 to 4 per 1000 children, appears to be increasing. This change may result from many factors, including improved documentation of the diagnosis in countries around the world, improved care of premature and sick infants, or other unknown factors (Nelson & Grether, 1999). The movement disorders associated with CP include spasticity, dyskinesia or dystonia, hypotonia, and ataxia. Spasticity is the most frequently occurring disorder and a mixture of various movement disorders are common. The accepted distributions of movement impairment include hemiplegia, diplegia, and quadriplegia (Dabney, Lipton, & Miller, 1997). Although improved care has resulted in typical life spans for persons with less significant involvement, those with severe quadriplegia and associated conditions may die earlier (Hutton & Pharoah, 2002; Strauss & Shavelle, 1998). Strauss, Cable, and Shavelle (1999) carried out an epidemiologic review of a large database targeting causes of death in CP. Their findings found elevated death rates from cancer and heart disease occurring at relatively young ages. Although this study awaits replication and support from clinical studies, the findings are provocative to say the least.
THE NEURODEVELOPMENTAL TREATMENT APPROACH AND PEDIATRIC THERAPY The intervention approach discussed in this chapter is the neurodevelopmental treatment approach, or NDT, originally called the Bobath approach. This paradigm hypothesizes that abnormal tone and impairments of movement and posture result from lesions in the CNS and limit the development of function. Intervention is aimed at minimizing these impairments and improving functional outcomes as a result of problem-solving among the clinician, client, and family to develop new movement strategies and management of postural tone. The original approach was developed by Berta and Karel Bobath, a physiotherapist and physician, respectively, who evolved the paradigm between late 1940 and 1990. Currently the instructors who teach the technique and the national Neurodevelopmental Treatment Association (NDTA) continue to expand and update the treatment approach. When Mrs. Bobath first began to practice as a physical therapist, therapeutic interventions for neuromuscular diagnoses were based on the stretching and strengthening regimens used with the impairments left after polio. Unhappy with the results of such treatments, Mrs. Bobath documented observations from her assessment and treatment of adults with paralysis after stroke and children with CP. Dr. Bobath supported her ideas with information from the neurophysiologic scientists of the day, including the hierarchic perspective of the CNS, the cephalad to caudal/proximal to distal nature of human development, and the concept that postural control evolved from primitive reflexes (Howle, 2004). The Bobaths’ early work focused on altering muscle tone and reflexes to enable the development of more normal movements and followed the normal developmental sequence in treatment. The importance of the postural reflex mechanism was highlighted and primitive reflexes were seen as a first step in the development of higher-level, skilled movements. The persistence of these reflexes in conditions such as CP originally was believed to block more skilled movement, hence the concept of reflex-inhibiting postures (RIPs), which were used to facilitate higher level movements (Bobath, 1955). Over time, Mrs. Bobath’s approach changed as she documented her observations about the results of her treatment. Although the concept of reflex inhibition, even today, is seen by some as the substance of NDT, Mrs. Bobath actually discarded this focus by 1964, moving on to the idea of “handling” or moving the
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 345 child so as to generate active movement responses. The treatment approach continued to focus on development of movement skills based on the normal developmental sequence until the lack of carryover outside of individual sessions became apparent. The Bobaths (1984) then acknowledged the importance of linking treatment to the performance of functional tasks in other settings, thus underscoring the importance of motor learning on the part of the client. Motor learning is defined as “a set of processes associated with practice or experience leading to relatively permanent changes in the capability for producing skilled action.” (Shumway-Cook & Woollacutt, 2001, p. 27).
Shumway-Cook and Woollacutt distinguish between motor learning and performance, citing changes in motor performance as being temporary, whereas permanent changes in skilled action result from true motor learning. Clearly for children with CNS dysfunction to change their occupational performance outside of therapy intervention sessions, true motor learning must take place. Current NDT treatment recognizes the importance of motor learning to skilled performance, and the necessity of practicing clientdesignated activities in treatment for changes in performance to occur. Although the Bobaths themselves did not incorporate motor performance into their theory, the Neurodevelopmental Treatment Association Theory Committee, consisting of multidisciplinary NDT instructors in the United States, began updating the theoretic paradigm in the early 1990s to incorporate current concepts with applicability to treatment of persons with neurologic deficits. It was at this time that theories such as dynamic systems theory and motor learning were formally integrated into the theoretic basis for the treatment approach (Howle, 2004). One of the challenges for clinicians is the constant need to keep their knowledge current with changes in knowledge generated by science, a challenge the NTDA has taken seriously, as evidenced by the work of the NDTA Theory Committee.
ROLE OF PERFORMANCE COMPONENTS ON OCCUPATIONAL PERFORMANCE Aspects of performance that therapists analyze when planning treatment for children with CP are components such as postural control, strength, muscle tone, spasticity, range of motion, and the performance of the
activity or occupation designated as the goal of intervention. Current studies provide a much clearer picture of the role such impairments and movement disorders have on performance skills. For example, Gordon and Duff (1999b) studied the relationship between fingertip force regulation in grasp, spasticity, stereognosis, two-point discrimination, manual dexterity, and perception of pressure sensitivity. Their work demonstrated a clear relationship among tactile perception, anticipatory control (activation of sensory and muscular systems for a specified activity based on prior learning and experience) (Shumway-Cook & Woollacutt, 2001) and task performance; however, it also suggested that the role of the other impairments in performance was dependent on the aspects of the activity being performed. They noted that spasticity appeared to affect the adjustment of grip to object weight and to the length of time between grasping and actually lifting an object, but it did not have a relationship to anticipatory control. The NDT approach emphasizes the importance of postural control and anticipatory postural control, both performance skills in the Occupational Therapy Practice Framework (The American Occupational Therapy Association [AOTA], 2002), to the outcomes of therapy intervention, or areas of occupation. The next section of this chapter discusses postural control and its impact on upper limb function.
THE RELATIONSHIP OF POSTURE TO UPPER EXTREMITY FUNCTION One of the Bobaths’ contributions to management of neuromuscular conditions was their understanding that spasticity was not just an individual muscle phenomenon, but actually affected posture and control of upright position in space, a concept not previously acknowledged. The emphasis on the postural reflex mechanism as central to changes in other aspects of motor performance was a principal factor in the Bobath treatment approach, which underscored their belief in the hierarchic, maturational principles of motor development. The Bobaths believed that more distal skills (e.g., reach, the ability to stand) could not develop until postural control of head and trunk occurred, defined as the postural regulation of the body’s position in space for purposes of stability and orientation (Shumway-Cook & Woollacutt, 2001). Therapists trained in the NDT approach through the 1980s focused on altering postural tone passively, then on facilitating active control in the head and trunk and finally on development of control in the upper and lower limbs. At the present time, NDT theory
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locates intervention for impairments such as postural control within the desired occupational performance outcome rather than as the primary treatment outcome.
POSTURAL CONTROL IN TYPICALLY DEVELOPING C HILDREN In typically developing children, postural control evolves from the development of antigravity movement, postural adjustment reactions, somatosensory input, and experience, and is defined as maintenance of body position in space (Nichols, 2001). Postural sway, a component of postural control defined as “the movement of the center of gravity within the base of support in any upright position” refers to the constant movement of the body when upright and occurs in a developmental sequence that matures around 13 years of age (Nichols, 2001, p. 275). Another aspect of posture, anticipatory postural control, defined as activation of sensory and muscular systems for a specified activity based on prior learning and experience, helps to provide efficient adjustments of the body to support use of the limbs for various activities (Shumway-Cook & Woollacutt, 2001). All motor activities require some degree of postural control, although those requirements vary depending on the activity and the environment in which it is performed. Bertenthal and Von Hofsten (1998) related postural control to hand function, specifying that postural control is a necessary requirement for the development of grasp and manipulation, and integration of vision into hand function. This constellation of postural control components was not well delineated during the Bobaths’ time; however, the current premise that postural control and its elements are necessary for successful motor performance supports some of the Bobaths’ ideas about the interaction of the trunk and upper limbs. For example, Bertenthal and Von Hofsten (1998) discussed the importance of postural elements to both visual skill and upper limb performance in tasks such as reach and grasp, noting that “. . . reaching for distal objects is necessarily a dynamic process demanding mutual and reciprocal processing of the relevant perceptions and actions” (p. 519).
Stapley, Pozzo, and Grishin (1998) studied the interaction of anticipatory postural control and reach in typical subjects. Their work suggested that the use of anticipatory postural adjustments plays a role in activation of upper limb movement from a fixed base of support before reach, as well as stabilizing the body during reach.
POSTURAL CONTROL AND ANTICIPATORY CONTROL IN C HILDREN WITH C EREBRAL PALSY In contrast to typical children and adults, children with CP have difficulties with postural control and anticipatory postural adjustments, as evidenced in a number of studies. Liao and co-workers (2003) found significantly worse postural control in sitting as demonstrated on parameters of static and dynamic sway indices in children with spastic CP when compared with typically developing children. Roncesvalles, Woollacott, and Burtner (2002) found that children with CP did not demonstrate increased muscle response to changes in platform perturbations, although typical children did. They hypothesized this difference in ability to demonstrate recovery of balance resulted from insufficient contraction of agonist postural muscles. Studies of anticipatory postural control demonstrate differences in children with CP as well. Van der Heide and co-workers (2004) found that children with CP after prematurity have difficulty adapting or grading postural adjustments to a variety of task-specific circumstances. Not unexpectedly, these difficulties were worse in children with diplegia or quadriplegia than in children with hemiplegia. A top-down sequence of activation of postural muscles, particularly in the neck extensors, was seen in their sample of children with CP, which varied from the muscle activation sequence seen in typical children. They noted that the gestational age of the child was related to postural adjustment problems; the shorter the gestation, the greater the impact on postural adjustment. There are different theories about the interaction of postural control and sensation and the role of anticipatory postural control in upper limb function, including the Dynamic Systems Approach and Neuronal Group Selection Theory. Howle (2004) contrasted and compared some of these theories as they relate to NDT. Although these theories present different perspectives on the topic of postural control and upper limb function, there is no question these elements of performance are an important factor to be considered in movement intervention, regardless of the theoretic perspective.
SENSATION AND ANTICIPATORY CONTROL IN HAND FUNCTION The Bobaths saw movement and sensation as complex, interdependent aspects of human performance (Howle, 2004). They hypothesized that lack of movement
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 347 control affected the ability to perceive and process sensation. Although the sequencing of sensation and movement proposed by the Bobaths may be open to question, there is no argument that persons with CNS lesions do have sensory impairments that affect their motor performance. Problems with sensory perception and sensory processing affect performance in a number of ways, including inability to detect and identify incoming sensory information; difficulty interpreting single sensory or multisensory input; problems with modulation of sensory inputs to match changes in task and environmental demands; and inability to match sensory information with experience, memory and specific tasks (Eliasson, Gordon, & Forssberg, 1995; Gordon & Duff, 1999a; Gordon & Duff, 1999b; Lesny et al., 1993; Yekutiel, Jariwala, & Stretch, 1994). Impaired development of anticipatory control during hand function also results from impaired sensation. Eliasson and Gordon (2000) described anticipatory control in object manipulation as “internal representations or sensorimotor memories of the object gained during previous manipulatory experience” (p. 233).
Researchers have carried out extensive studies over recent years in an attempt to isolate the role of sensation in prehensile and release functions in typical adults and children (Forssberg et al., 1991; Kinoshita et al., 1992; Eliasson, Johansson, & Westling, 1992). This series of studies was followed by a body of research looking at issues of vision, tactile sensation, spasticity, and force generation in grasp and release. Comparisons of these parameters in grasp and release between children with CP and typical children also were performed (Duff & Gordon, 2003; Eliasson & Gordon, 2000; Eliasson et al., 2003; Gordon, Charles, & Duff, 1999; Gordon & Duff, 1999a; Gordon & Forssberg, 1995). This work has established that the grasp and release of children with CP is impaired by deficits in tactile perception and processing, difficulty with graded control resulting from balanced interactions between muscle agonists and antagonists, and temporal control of movement events (Eliasson & Gordon, 2000). Temporal issues were cited again in the work of Gordon and co-workers (2003), who found that release of objects that varied in weight required more time in children with CP than in typical children, especially when accuracy and speed were necessary. This discussion underscores the notion that motor behaviors, sensory perception, and sensory processing are inextricably linked, and that experience and practice with various motor behaviors helps to build performance and anticipatory control in children with CP. This is true for all aspects of motor performance,
including postural control, hand function, gait, and speech.
KINESIOLOGIC ASPECTS OF TRUNK AND ARM FUNCTION The problems with postural control and upper limb function seen in children with CP affect all aspects of occupational performance. It is for this reason that evaluation of posture, postural adjustments, and their interactions with the upper limb particularly should be part of a therapeutic assessment, as well as the status of body structures.
TYPICAL TRUNK AND U PPER LIMB I NTERACTIONS The axial skeleton is the base upon which the limbs are supported and from which they operate. The alignment of the spine, pelvis, and ribs influences how both the upper and lower limbs rest in space and how their movements are used in the performance of various activities. Remember that many of the muscles controlling the upper and lower limbs attach to the spine, rib cage, and pelvis, and that the shoulder girdle moves over the rib cage. The anatomical connections between these musculoskeletal units are why mobility and stability of the entire trunk are so important to movement of the limbs (Neumann, 2002). The pelvis provides support for the spine. Because the lumbar spine interacts specifically with the pelvis in virtually all movement sequences (e.g., forward flexion, extension, rotation, lateral flexion), motor or joint impairments in one or the other structure affect movements in both areas. Similarly movements in any region of the spine result in movements within the entire spine, with the degree of the resulting motion decreasing distally from the originating movement. Therefore disruption of motion in one region of the spine affects the entire spine, and by association, the position of the head in space (Neumann, 2002). In children with CP, both structures and movements of the axial skeleton often are impaired, affecting both posture and limb function. Such limitations in the biomechanical interactions of the pelvis and spine are concerns for therapy intervention in the child with CP. The shoulder girdle is comprised of the scapulae, clavicles, sternum, and glenohumeral joints. Just as with the spine and pelvis, dysfunction at any one joint of the complex affects movement at all of the other joints. The shoulder, elbow, and forearm place and sustain the wrist and hand in space for function.
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Arranging hair on the back of the head, clipping toenails, bathing, and dressing are all examples of activities that require the hand to be moved to a distance away from the body. In typical movements, certain shoulder complex functions are aided by actions of the spine. For instance, rotation and flexion of the lumbar, thoracic, and cervical spine extends the range of reach for items high on a shelf or under a bed. The rotary movements of the shoulder and forearm are particularly important to skilled dexterous movements within and between the hands, both at and away from midline. Removing post earrings, for example, requires the palms of the hands to be facing each other on one side of the body, an action that would not be easily performed without humeral and forearm rotation. Finally, the complexity of wrist and hand movements is significant and remarkable for the highly complementary nature of the interactions among various structures. Consider playing the piano and the configuration of the wrist and fingers. During an octave stretch, the wrist may be flexed to provide additional range of movement in abduction and extension at the fingers. When a chord is played, the wrist is extended to provide power, stability, and control for the flexed fingers. Knowledge of these kinds of interactions assists the therapist to both understand and treat limitations in occupational performance that involve the hands. Awareness of the complex structures in the hand is critical as well, including the carpal, metacarpal, phalangeal joints, and arches.
BASE OF SUPPORT AND U PPER LIMB FUNCTION Another biomechanical aspect of upper limb performance is the base of support generated for upper limb function, basically the foundation of the head, trunk, and limbs. Shumway-Cook and Woollacutt (2001) define base of support as “the area of the object in contact with the support surface” (p. 164).
A wide base of support, such as the feet widely separated in standing, provides stability for motor functions, whereas a narrow base of support in sitting and standing is more conducive to body mobility. One also needs to consider the nature of the supporting surface; some properties of various surfaces enhance contact with body structures, such as beanbag chairs. Age, the nature of the activity, and the environment are other factors that affect the base of support incorporated by the individual.
In movement disorders such as CP, base of support is affected by the movement disorder itself, structural issues such as hip dislocation, and elements related to the movement disorder such as limited postural control. Age, task constraints, and the physical environment mentioned previously should be considered when carrying out assessments of performance in which base of support is an issue. Interventions used to develop more skilled action in NDT are designed to take into consideration base of support and its impact on the individual’s ability to perform upper limb functions.
BIOMECHANICAL INTERACTIONS OF THE UPPER LIMB IN CEREBRAL PALSY Depending on muscle tone and distribution of motor impairment in the individual with CP, there are commonly fluctuations in movement control that affect position of the spine and pelvis and postural adjustment responses (Liao et al., 2003; Van der Heide et al., 2004). These difficulties can be increased by tightness in the soft tissue structures of the lower limbs, such as the hamstrings and hip flexors (Reid, 1996). Such problems in the axial structures influence purposeful movements in the upper limbs of children with CP. Posterior tilt of the pelvis and flexion of the lumbar spine increase thoracic flexion and compromise actions in the shoulder girdle and shoulder. As discussed, changes in any aspect of shoulder girdle function influence the entire shoulder girdle complex (Neumann, 2002). Scapulohumeral rhythm is commonly affected by increased thoracic flexion, causing the scapula to rotate upward sooner in the interaction of the two structures and sometimes limiting the range of overhead action. Movements in the frontal plane, such as humeral flexion and horizontal adduction, seem to be difficult for children with CP, resulting in the increased presence of humeral abduction and sometimes humeral extension. External rotation of the humerus is affected by both increased thoracic flexion and the resulting scapular abduction, which biomechanically aligns the humerus into an internally rotated posture. This configuration is most often seen in children with spasticity; those who have dyskinesia or dystonia may seek to control extraneous movement in their upper limbs by holding their upper limbs against their bodies in a practice called “fixing” or stabilizing the upper limb (Nichols, 2001). This practice volitionally can limit their humeral motions initially; however, if the practice persists, actual soft tissue limitations can occur.
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 349 Movement of the body and limbs as a unit is a characteristic seen in CP (Hadders-Algra et al., 1999). Isolation of movement in the various segments of the upper and lower limb is missing, causing a lack of disassociation between the movement elements between and within each limb. For instance, the motions used in the shoulder girdle and humerus affect movement components seen in the forearm and wrist. Humeral abduction and internal rotation facilitate overuse of forearm pronation and limit active supination needed for efficient hand use, a common problem in children with spastic CP. Active elbow and wrist extension is often restricted by spasticity in the elbow and wrist flexors, over time causing muscle tightness and contracture. The predominance of flexion at the elbow and wrist also affects the development of active intrinsic muscle function in the hand, resulting in the use of tenodesis interaction between the wrist and fingers and the use of extrinsic finger flexors and extensors to control the digits. Types of grasp available, especially for children with more severe impairments, are limited to more primitive grasp sequences and lack of both power and precision prehensions. Deformities of the web space of the thumb and hypermobility in the metacarpophalangeal (MCP) and distal interphalangeal joints of the thumb are common. These atypical interactions in the upper limb of children with CP result in significant activity and occupational limitations. Some authors hypothesize that the movement alterations are actually an adaptive function rather than true movement impairments (Steenbergen, Hulstijn, & Dortmans, 2000). Whatever the cause of the movement limitations, the manipulative function needed to manage such items as clothing fasteners, the ability to write, and use scissors, is often either impaired or missing. Clinicians should assess the child’s postural control and upper limb function as a whole to design interventions that enhance all aspects of performance.
CONTRASTS BETWEEN HYPOTONIA AND HYPERTONIA The discussion to this point has addressed postural control, anticipatory postural control, the relationship of posture to upper limb function, and aspects of atypical motor performance in children. Most of the discussion has related to the child with spasticity and increased tone. Muscle tone refers to the resistance a muscle offers when lengthened (Shumway-Cook & Woollacutt, 2001). This resistance is a result of both neural factors (e.g., spasticity) and biomechanical factors (e.g., fibrosis, atrophy, changes in contractile properties of some muscle fibers).
Children with hypertonia have increased stiffness or tone in their muscles, whereas children with hypotonia have decreased resistance to lengthening and laxity of both muscle and other soft tissue structures around the joints. It is not uncommon to find children with hypotonia in the trunk and hypertonia in the limbs, or those with fluctuating tone, as well as children with generalized hypotonia. The intervention approaches to these variations in muscle tone differ in that children with hypotonia use end range movements (activities carried out by motions at the end of the available joint range) and often have increased range of motion in contrast to the limited active and passive mobility seen with hypertonia. Children with underlying low tone often use stabilizing or fixing of a body part (Nichols, 2001) to create stability, as well as a wide base of support in upright positions to create postural stability. Body movements are characterized by straight plane actions without a rotary component and limitations in strength and endurance are common. In the upper limb and hand, lack of graded, efficient movements restrict refined functions such as precision grasp, interdigital interaction, and isolated digital control used in complex manipulative sequences. The intervention procedures differ somewhat, although the emphasis on postural control as a necessary element of performance remains unchanged.
TREATMENT APPROACHES: CONCEPTS OF INHIBITION AND FACILITATION Three concepts underscore therapeutic handling (facilitating active movement by using a hands-on approach) in the NDT treatment approach, key points of control, inhibition, and facilitation. Key points of control refers to specific hand placement by the therapist during handling that allows direct influence or control over the area and indirect control over other body structures or functions proximal or distal to the key point. These sources of control are used to either inhibit or facilitate movement sequences and postural control. Proximal key points include the pelvis, shoulder girdle, and trunk, whereas distal key points are areas such as the elbow and ankle. Inhibition is defined as “the reduction of specific underlying impairments that interfere with function” (Howle, 2004, p. 261).
In treatment, therapists use inhibition to limit the ungraded force produced by spasticity, to balance unequal power between antagonists and agonists, or to
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limit those movements that impair smooth coordinated action. Facilitation consists of “strategies employed in therapeutic handling that make a posture or movement more likely to occur” (Howle, 2004, p. 260).
It is used to activate, grade and change various movements, and should affect the direction, force and availability of various movements. Specific techniques are used for inhibition and facilitation (Box 16-1). These are discussed next.
I NHIBITORY TECHNIQUES Inhibition is the primary tool used to manage abnormal posture and tone. Specific “hands-on” inhibitory techniques such as vibration, use of mobile surfaces, location, position of structures within the treatment environment, and use of various sensory stimuli and speed of movement can all be used to minimize impairments. Vibration in NDT consists of placing the hand on a body area and vibrating or oscillating the location gently and consistently. Use of mechanical vibrators is discouraged because of the noise and difficulty grading the intensity of the vibration. This technique is best used when a more global movement or gross motor activity is being performed so as not to interfere with performance. It is particularly useful when managing trunk tone for vocalization or extending the range of movement in the trunk or a limb. As with all inhibitory techniques, one should withdraw the technique during activity performance. Prolonged stretch through weight bearing in both upper and lower limbs is an inhibitory technique used to elongate soft tissue structures and minimize flexion
BOX 16-1
Specific Techniques Used for Inhibition and Facilitation
INHIBITORY TECHNIQUES • Vibration • Prolonged stretch • Therapist guidance of movement • Use of mobile surfaces • Inhibition through activity FACILITATION TECHNIQUES • Deep pressure and joint approximation • Weight bearing on both upper and lower limbs • Vestibular input • Environmental modifications • Sensory modifications • Combining inhibition and facilitation
or extension synergies in the limbs. It can be used to increase range of movement and decrease tone in children with spasticity, or in children with hypotonia or athetosis who have decreased range caused by fixing body parts to limit extraneous motion. Therapist guidance of movement has applicability for both inhibition and facilitation. For inhibition, the therapist uses key points of control to limit ungraded force in one muscle group while facilitating active movement in the agonist or antagonist. It can be particularly helpful in the case of hemiplegia, in which asymmetries exist, or in the cases of diplegia and quadriplegia, in which symmetry of limb posture and lack of dissociation of movement is a problem. In these circumstances, the therapist can inhibit asymmetry by directing activities that are bilateral or symmetric in nature, or by inhibiting symmetry of posture by using treatment activities that require the limbs to be used reciprocally. Use of mobile surfaces has both inhibitory and facilitatory applications. Children who have increased trunk extensor tone accompanied by lower limb extension can be positioned on a mobile surface and the gentle rocking movements of the surface used to inhibit tone and relax the child. Over time, passively applied movement on a mobile surface is shifted to the facilitation of the child’s ability to use his or her own active motion to manage tone increases. Inhibition through activity is when the therapist teaches the child or individual how to manage atypical movements or increases in stiffness through specific movement sequences. For example, in the child who has increased tone in the flexors of the upper limb that limits dressing or bathing, upper limb weight bearing against a wall or the floor can help inhibit the flexion posture, or bending from the waist and shaking the arms in space can help reduce the stiffness. Whenever possible, clients should be taught to use their own movement over time for health promotion and increased participation.
FACILITATION TECHNIQUES The use of key points of control combined with therapist guided movement plays a big role in facilitation. Remember that key points of control are body areas from which the therapist facilitates or inhibits movement. In facilitation, the goal might be to assist the client to open a cupboard door using a more involved upper limb while the unimpaired limb holds and then places an item into the cupboard. The therapist could use either the shoulder or elbow as a key point of control to facilitate placement of the impaired arm on the door handle, a task that the client cannot do without prompts.
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 351 In this same example, tapping could be used along the muscle belly of the elbow extensors to activate the movement necessary to extend the arm to the door handle. Tapping can be used alternatively with tactile cues, which are a firm touch on the body part to indicate that it needs to move. Tactile cues are a less invasive form of facilitation, so moving back and forth between the two techniques is one way to withdraw input as the client is more able to perform the desired activity with less assistance. Deep pressure and joint approximation are facilitation techniques to activate cocontraction around the joints. The use of these techniques works best on low-toned persons, but those with high tone often demonstrate underlying low tone when their high tone is altered. Sequencing deep pressure and joint approximation after tone inhibition is a common practice to facilitate better control and muscle activation. Weight-bearing on both upper and lower limbs has properties of facilitation, as well as inhibition, depending on how it is applied. Static weight-bearing, especially for extended periods of time, can be achieved by “locking” or hanging on the joints. However, if weightbearing is accompanied by weight-shifting (volitional or assisted movement of body weight) and active movement sequences, it can facilitate active movements in various muscle groups. Weight-shifting refers to movement of body weight through momentum of a body part (Shumway-Cook & Woollacutt, 2001). Active weight shift occurs in all volitional movement transitions and is an important therapeutic tool in persons with movement impairments resulting from neuromuscular disorders. In the upper limb, humeral flexion, elbow extension and possible wrist and finger extension can be facilitated by weight-shifting over weightbearing positions. Vestibular input can be used to facilitate postural control. Combinations of sensory-integrative techniques can be incorporated, using swings or platforms (Blanche, Botticelli, & Hallway, 1995). If the child is not capable of sitting independently or sustaining posture on such equipment, the therapist can sit on the device with the child in his or her lap. A more desirable option is to incorporate meaningful activities such as dance with repeating rotary turns into the treatment whenever possible. Environmental modifications include arrangement of physical, sensory, and even social aspects of the environment to facilitate action. Pediatric therapists are particularly good at such modifications. Arranging the room so that items are placed strategically so as to encourage active movement, use of surfaces that challenge the abilities of the child, and use of materials in occupations that are meaningful to the child are all ways to facilitate skilled action and successful perform-
ance. These same kinds of modifications can apply to specific aspects of hand function as well. For instance, using checkers instead of pennies to facilitate elements of a precision prehension can ensure success for the child and build the motor and sensory aspects of activity demands. Sensory modifications can be helpful too. Music that is invigorating or calming can be used, singing, use of high contrast, complex or simple visual backgrounds are some ways to alter the sensory environment. Use of social facilitation is another technique that has been enhanced by inclusive practices in the classroom (Kellegrew, 1996). Peer engagement and support can serve to motivate and facilitate children in ways that parents or therapists cannot achieve. Children’s desire to be like their peers is a powerful force in facilitating performance, especially in the achievement of activities and occupations that the child wishes to perform to be with friends.
COMBINING I NHIBITION AND FACILITATION In almost any treatment session with children who have CP, it is necessary to combine aspects of inhibition and facilitation. This requires considerable skill on the part of the clinician, especially in the case of active children. By altering movements through the use of facilitation or inhibition, the clinician causes the client to change or adapt. This requires the clinician to quickly alter hands-on input to continue to enhance the improvement in the child. Ultimately the goal is to be able to withdraw both kinds of techniques so that the child can demonstrate motor learning and carryover of the skills learned in therapy.
THE ASSESSMENT PROCESS Assessment of the child with cerebral palsy can be complex. Multiple aspects of performance should be analyzed, including physical and sensory status, developmental status, postural control, and quality of movement elements. The challenge for the clinician is how to sort through these aspects of the client to see which appear to be most critical to occupational performance. Distribution and degree of movement impairment also can be a guide. Children with mild hemiplegia, for instance, may not need extensive physical assessment but based on research findings (Gordon & Duff, 1999b) need assessment of tactile function. Developmental and occupational assessments are appropriate. A child with severe quadriplegia is more likely to need physical status assessment (e.g., strength, range of motion, spasticity) and less likely to need a full developmental evaluation.
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Various assessments are discussed next, including standardized tools whenever possible.
PHYSICAL STATUS OF THE I NDIVIDUAL Range of motion and muscle strength are assessed using standard goniometry and manual muscle testing. Argument existed for some years about whether accurate evaluation of strength was possible in children with muscle tone impairments, however, the existing literature on functional gain after strengthening programs makes this a relevant area to assess (Damiano, Vaughan, & Abel, 1995; Darrah et al., 1999; Dodd, Taylor, & Damiano, 2002). Muscle tone is assessed through the use of tools that are somewhat subjective, including the Ashworth Scale (Bohannon & Smith, 1987). The Tardieu Scale’s use is evolving; however, it requires more time and expertise to achieve accurate results (Mackey et al., 2004). These two scales assess increased tone but are not particularly helpful with hypotonia. Existing tools to measure decreased tone directly do not exist. Assessment of sensation is a time-consuming process that often is not carried out in children with CP in spite of a body of research indicating tactile discrimination deficits in children with CP, particularly hemiplegia and quadriplegia (Duff & Gordon, 2003; Eliasson & Gordon, 2000; Eliasson, Gordon, & Forssberg, 1995; Gordon et al., 2003; Gordon, Charles, & Duff, 1999; Gordon & Duff, 1999a). Gordon and Duff (1999b) and Lesny and co-workers (1993) used a variety of measures in their work that are recommended for clinical practice, including tests of two-point discrimination, stereognosis, and deep pressure. NDT emphasizes quality of movement. Existing tools that assess quality of movement are limited. Examples are the Gross Motor Performance Measure (Boyce et al., 1995; Gowland et al., 1995; Thomas et al., 2001), the Toddler and Infant Motor Evaluation (TIME) (Miller & Roid, 1993; Rahlin, Rheault, & Cech, 2003), and the Movement Assessment of Infants (Hallan et al., 1993; Harris et al., 1984). The limitations in standardized tools that assess movement and posture are a concern for the NDT treatment approach because the treatment emphasis is on developing posture and movement. Researchers have options available to them, but these are too expensive and complex for the clinic. Nichols (2001) suggested using indirect observation during assessment of motor milestones, which is the best option available in the clinic at present. The success of any therapeutic intervention is dependent on the therapist’s ability to analyze aspects of performance and change over time. When one is planning interventions that use an NDT treatment
approach, remember that the approach addresses posture and movement in the context of occupational performance. This means that occupational performance needs to be assessed. Pediatric therapists have a host of tools available to them in this realm, some of which have a developmental or skill focus. The reader should see Asher (1996) for a complete listing.
TREATMENT PLANNING Planning appropriate interventions and documenting outcomes are aspects of service provision that require careful attention. Setting appropriate goals is the cornerstone of treatment planning. As noted in the OT Practice Framework, the occupations selected as outcomes of intervention should be meaningful and purposeful to the client and family; and successful outcomes are more likely when occupations are incorporated into daily routines (AOTA, 2002). These premises hold true for NDT intervention just as they do for other treatment approaches. Use of activity analysis and the principle of partial participation are useful tools to help build specific skills over time (Vogtle & Snell, 2004). Refer to Table 16-1 in Case Study 1 for one example of activity analysis that is useful when planning NDT intervention. Sensory and motor elements are delineated to assist the clinician in organizing treatment and incorporating strengths of the client. Partial participation, which enables clients to complete steps of an activity that they are able to do with the remaining steps completed by a caregiver, can be planned satisfactorily through the use of this kind of activity analysis (Vogtle & Snell, 2004). Breaking an activity into steps also helps the clinician evaluate treatment outcomes in a more systematic manner. Another aspect of treatment planning that benefits from activity analysis and partial participation is the integration of accommodations into interventions. By breaking an activity into steps and sorting out which of those the client can do, modifications to promote successful performance can be easily identified and used in treatment. This has the extra benefit of giving the clinician the opportunity to see if suggested modifications really work before asking families and educators to make them. Tables 16-2 and 16-4 in the Case Studies later in the chapter give illustrations of how a clinician could use an activity analysis to plan treatment. The tables include columns for activity steps, movement components, and facilitation techniques. Organizing treatment into this kind of table can help the clinician develop a plan for intervention that includes aspects of facilitation and inhibition.
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THE INTERVENTION PROCESS Once assessment is complete and goals are established by the family, child, and clinician, it is time to consider how to provide treatment. The use of NDT techniques means that the therapist needs to combine the client factors to be addressed (e.g., tone, weakness, range of motion, postural control issues) with performance skills and activity demands of the goal while learning and practicing identified activities or occupations. The nature of the occupation selected as a goal in conjunction with client factors dictates the degree of postural control integrated into the intervention. If the goal activity is focused on hand function, then the level of postural control and adjustment factored into the session depends on the planes in which the hand function takes place and future postural control goals. For instance, tying shoes occurs at some distance from the body. Potentially there should be either more work on posture involved in this kind of activity than if the goal was handwriting, or the therapist should develop postural supports necessary to allow the hands to be free for the act of shoe-tying. The base of support required by an activity during intervention depends on the movement transitions needed during performance, and on the degree of body stability required by activity demands when adjusted by client factors. For instance, a child with significant quadriplegia may not be likely to use isolated trunk control, so a wider base of support might be chosen during hand function activities to contribute to the child’s stability. A less involved child who is mobile and has elements of active trunk control would be more likely to benefit from working on a narrower base of support. Base of support can be graded over time as progress is seen. It is also important to remember if the child is in supportive seating during the day, the practice part of sessions needs to take place in the same configuration. Base of support can affect the degree of weight shifting used in treatment. Large weight shifts obviously are important to movement transitions; however, lesser degrees of weight shifting can play an important role in upper extremity treatment. Sitting at a table and cutting with scissors, for instance, usually incorporates subtler weight shifts. If the child reaches for items set back from the edge of the table, an anterior weight shift occurs. Similarly, reaching for items off to the side results in a lateral weight shift. Using subtle weight shifts assisted by key points of control when working on table top activities and development of fine motor skills can extend reach and assist with hand placement, as well as inhibiting extensor tone in the trunk.
Weight shifts can assist in inhibition of tone and facilitate active trunk and upper limb function. Other facilitation and inhibition techniques can be applied during treatment of hand function as well. Gentle vibration or oscillation on the trunk or limbs helps to manage upper limb tone and use of the shoulder or elbow as key points of control facilitates active movements in the wrist and hand. Preparatory activities using upper limb weight bearing prepare the hand for more active hand function by inhibiting tone and improving mobility of wrist and finger flexors. These activities can take place with the child in sitting or standing, not just in quadruped, positions in which upper limb weight bearing often takes place in typical children.
N EURODEVELOPMENTAL TREATMENT AND HAND FUNCTION There are children in whom the primary intervention focus needs to be within the hand. Examples are children with quadriplegic involvement in which the most important goal is isolated index finger function to access a computer or augmentative communication device; a child with hemiplegic impairment who wants to be able to hold a piece of paper in the impaired hand so that cutting can be accomplished; or a young person who wants to be able to manipulate a joystick to drive a power chair. In these kinds of examples, direct treatment of the hand is necessary. Most of the inhibition and facilitation techniques described earlier can be applied directly to the hand. Vibration or oscillation at the wrist or from the web space of the thumb minimizes tone in the fingers; these techniques can be used as preparation before performance or used during activities. Weight bearing on the hand is a well-known NDT technique for soft tissue stretch and tone management that is underused in reciprocal hand interactions such as handto-hand clapping games with another person, in which hand contact is extended for the purpose of stretch, deep pressure, or tone management. The degree of wrist and finger extension involved in the activity can be graded by the therapist depending on the desired outcomes and the tolerance of the child. Key points of control in the hand include the wrist, longitudinal arch of the hand, MCP joint of the index finger, thenar eminence, and web space of the thumb. Obviously the use of key points of control has to be carefully managed in such a small area as the hand, which is when careful grading of activities comes into play. For example, when isolated control of the index finger is desired, the therapist may choose to use the MCP joint as a key point of control. Activities that might be used to facilitate sensorimotor experiences in
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this situation include pushing keys on a piano, computer, or toy, pressing stickers onto a surface, making fingerprints in play dough, extending the digit for placement, removal of a ring, and so forth. Those activities that entail pressure (e.g., play dough, pressing keys, stickers) are situations in which weight shifts across the pad of the digit provide alternating deep pressure inputs into the interphalangeal (IP) joints, as well as the MCP joint, a facilitatory technique. The mobility of the carpals and metacarpals of the hand contribute to the arch structures of the hand, wrist flexion and extension, and radial to ulnar side interactions within the hand. All of these elements also play a role in grasp and manipulation between and within the hands. Hypertonic CP commonly results in a predominance of wrist and finger flexion combined with ulnar deviation at the wrist—resulting in ulnar prehensions. Maintaining mobility in the structures of the hand mentioned earlier while facilitating active movement and the ability to participate in chosen occupations are focal concerns of NDT treatment. Although the prevailing muscle tone in the hand is increased with generalized hypertonia, hypermobility in the IP joints of the fingers and thumbs is common, as well as in the MCP and carpometacarpal joint of the thumb. This combination of increased mobility and fluctuating tone in the spastic hand presents challenges for the therapist and the need to alternate strategies of inhibition and facilitation frequently when working within the hand. Activity demands should be considered as part of treatment as well. AOTA (2002) defines these demands as “. . . objects, space, social demands, sequencing or timing, required actions, and required underlying body functions and body structure needed to carry out the activity.” (p. 624).
Specific aspects of any activity are items that should be considered in treatment, and amended or modified when necessary to enable the client to have success in performing the occupation. Nowhere is this more important than when working within the hand. For example, it is common for therapists to choose the smallest possible items to develop skills such as tip-totip prehension. Larger items offer the child better control and incorporate the same movement sequences used in precision prehension; as skill is gained, the therapist can then move on to include small objects in therapy. Practicing occupations during treatment has been emphasized in this chapter. There is a body of research supporting the efficacy of activity practice in children with cerebral palsy (Duff & Gordon, 2003; Taub et al., 2004) and the importance of activity context on practice outcomes (Volman, Wijnroks, & Vermeer, 2002).
It is critical that the therapist spend significant time having the client practice designated goals during the session. The therapist can use inhibition and facilitation in this process, but needs to withdraw such assistance as the session moves on, remembering that ultimately the child is expected to do the task without such assistance.
E FFICACY OF N EURODEVELOPMENTAL TREATMENT Judgment about the efficacy of therapeutic interventions should be based on careful examination of published studies, either through systematic review or meta-analysis. Such methods are limited by the limited availability of high-quality studies. Two recent systematic reviews of NDT intervention have been carried out (Brown & Burns, 2001; Butler & Darrah, 2001). Butler and Darrah (2001) incorporated articles back to 1973, whereas Brown and Burns (2001) included those published since 1975. There were 21 studies in the review by Butler and Darrah (2001) and 17 articles in the review by Brown and Burns (2001). Both reviews classified articles as one of five levels of evidence. Brown and Burns (2001) used the Quality Assessment of Randomized Clinical Trials scale created by Jaded and co-workers (1996) to assign levels of evidence, whereas Butler and Darrah (2001) used a system developed by the American Academy of Cerebral Palsy and Developmental Medicine (Butler & Darrah, 2001). Another unique feature of their review is their incorporation of dimensions of disability reflective of the National Center for Medical Rehabilitation Research (NCMRR) model of disablement (ShumwayCook & Woollacutt, 2001) as one judgment of outcome. Both reviews cited numerous problems in attempting systematic study of NDT. Problems included heterogeneity of the target population, lack of randomization, inadequate blinding of subjects, a wide range of subject ages, use of a variety of clinical and standardized outcome measures, small sample size and limited follow-up, interventions that included other methods besides NDT, a range of duration and intensity of treatments, and inconsistency of significance across studies. Both studies concluded that the efficacy of NDT could not be decided on the basis of the studies reviewed, although Butler and Darrah noted that studies published in the last 14 years had more statistically significant results. In addition, both noted that newer interventions based on more current theories of motor learning and skill development exist and appear to be generating more conclusive evidence (Butler & Darrah, 2001). Butler and Darrah cited the lack of association to any of the NCMRR dimensions to which the various studies were compared. These
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 355 same authors suggest that the use of NDT as a control intervention in studies comparing it to another treatment would contribute to the body of existing evidence about treatment efficacy for children with CP. Since these two systematic reviews were published, other publications about efficacy of NDT have been published (Trahan & Malouin, 2002; Tsorlakis et al., 2004). Trahan and Malouin’s research was a pilot study analyzing the outcomes of an intermittent intensive NDT intervention. Tsorlakis and co-workers (2004) research was a carefully designed randomized clinical trial comparing outcomes between two different durations of NDT treatment that attempted to avoid design problems of earlier studies. Duration of intervention has become a focus of studies because of the development of constraint-induced therapy that provides intensive duration of therapy over a relatively short term (Taub et al., 2004).
SUMMARY This chapter has described the neurodevelopmental treatment approach to pediatric intervention, and its history, evolution, and current perspective. As reiterated throughout the chapter, NDT is an intervention focused on improving postural control and active movement skills. The therapist bears the responsibility for integrating this kind of approach into function and practice of function. Carryover of movement changes into function does not occur naturally, as once proposed by the Bobaths. Although the efficacy of NDT has yet to be demonstrated convincingly, more recent studies are supportive and suggest that the shift to integration of NDT with functional outcomes has merit in the treatment of upper limb function in children with CP.
CASE STUDY 1 A C HILD WITH C EREBRAL PALSY Seven-year-old Jodie, who had spastic CP of quadriplegic distribution, used a head-activated switch to work on the computer, which meant scanning the keyboard rather than being able to use direct selection of desired keys. Her school therapists, teachers, and family wanted to explore the possibility of hand activation of Jodie’s computer access switch with the eventual goal of direct selection on an alternative keyboard, which would be faster and more productive. Although computer use in the context of the school environment was the initial occupational goal, success meant she would be able to access her home computer with less assistance than she presently required. TASK ASSESSMENT AND GOALS Activity analysis of the process of pushing a switch (Table 16-1) and physical assessment of Jodie’s ability to push a switch with her hand were carried out, along with an assessment of performance components, activity demands, and client factors in the OT Practice Framework (AOTA, 2002) and of performance components in Uniform Terminology III (AOTA, 1994). Jodie demonstrated challenges in motor and process aspects of performance skills. She maintained her head in an upright position for long periods of time and used it to move her eyes when tracking items. Efforts at arm and hand movement affected movements of her head and trunk, resulting in dynamic tone changes throughout her body manifested by increased
extension in her torso, head, and neck, and by bilateral rigid extension at the elbows and in the lower limbs. A consistent lean to the left was noted, a trend made worse by her attempts to use her hands. She could lift her arms actively by flexing and elevating her shoulders to about 80 degrees but movement toward or away from the midline to place her hands was difficult. There were soft tissue restrictions in her shoulders, limiting the end range of humeral flexion and abduction. Jodie’s hands were most often fisted and wrists stiffly extended. A right hand preference was noted. Jodie reached for offered items directly in front of her body but was unable to grasp an object volitionally or bring her hands to her mouth. When a toy was placed in her hand, she would hold it indefinitely using increased flexor tone in the fingers of her hands but was unable to do anything with it; there was no volitional release of objects and efforts to do so resulted in head shaking in an effort to release items from her hand. There was no isolation of movement between limbs or within either limb. Jodie could place her hand on a 5″ × 7″ switch placed in front of her with difficulty, but could not consistently depress and release the switch to use it for computer access, nor could she remove her hand from the switch once it was placed there. The movement components she needed to activate the switch for various aspects of the activity are noted in
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Table 16-1
Activity analysis of activating/deactivating a switch for computer use
Step of Activity
Visual Component
Moves arm to switch
Auditory Component
Movement Components*
Tactile Component
Locates switch
Lifts right arm toward the switch using humeral flexion and horizontal abduction. Elbow extension
Kinesthetic feedback from the limb moving
Places hand on switch
Sees switch and uses vision to guide placement of hand on switch
Humeral extension activated to bring hand to switch
Jodie feels the switch under her fisted hand
Presses switch to activate
Sees scanning array activate when switch is pressed
Hears click as switch is activated
Humeral extension is used to push the switch
Jodie feels the pressure of the switch on her hand increase as she pushes
Releases pressure on the switch
Uses vision to guide her hand lifting to release switch pressure
Hears click as pressure is released and switch deactivated
Humeral flexion is used to lift her hand off the switch
Feels absence of sensation as her hand clears the switch
Moves arm and rests hand on the surface away from the switch
Sees hand lift off of switch and targets where hand is to rest
Moves arm away from the switch using humeral flexion and horizontal adduction; humeral extension is used to lower arm to the table surface
Feels table surface under her hand and arm when she rests them on the table
*Because the client has stiffly extended elbows, which become stiffer with efforts at movement, the choice made is to focus on humeral movements to move her hand. Use of wrist flexion and extension also would be helpful; however, these movements are not absolutely necessary to activate the switch.
Table 16-2. The use of these movements for activating the switch were felt to be appropriate because Jodie’s volitional control of her elbow, wrist, and hand movements was minimal, and the switch could be successfully activated using these movements. In addition to movements to activate and release the switch, she needed to be able to organize and sequence these movements with enough speed to push the switch in a timely fashion when visually cued to do so by the scanning sequence. Thus anticipatory control in her arm (remember that anticipatory control was defined as activation of sensory and muscular systems for a specified activity based on prior learning and experience), postural control and adjustment of her head, and active isolated movements of her right upper limb were other aspects of performance needed for
motor control and learning so that she could initiate, sustain, and terminate movements of the shoulder in sequence to perform the activity. TREATMENT PLAN The organization of the treatment plan for Jodie is detailed in this section and based on a school year with weekly sessions. The treatment plan incorporates both environmental and client factors, as well as practice of the skill being developed during sessions and at home outside of the therapy setting at school. THERAPY GOALS The goals found in Box 16-2 include long-term goals and benchmarks as seen in an individualized educational plan (IEP) write-up. Benchmarks were chosen that support the
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Table 16-2
Facilitation and inhibition techniques to be used in Jodie’s treatment
Step of Activity
Movement Component
Facilitation/Inhibition Techniques
Moves arm to switch
Lifts right arm toward the switch using humeral flexion and horizontal abduction. Elbow extension
Tapping under the humerus to facilitate shoulder flexion and elbow extension; tapping on the medial border of the arm to facilitate horizontal abduction; forward then lateral weight shift of torso across the pelvis to facilitate arm movement in a sagittal then lateral plane
Places hand on switch
Humeral extension activated to bring hand to switch
Sweep tap across volar surface of the humerus; posterior weight shift of torso across the pelvis to facilitate arm movement toward the switch
Presses switch to activate
Humeral extension is used to push the switch
Active assist from head of humerus or on the forearm to facilitate pressure on hand to activate switch; lateral weight shift of torso across the pelvis to facilitate switch activation
Releases pressure on the switch
Humeral flexion is used to lift her hand off the switch
Tapping under the humerus to facilitate shoulder flexion and elbow extension; tapping on the medial border of the arm to facilitate horizontal abduction; forward weight shift of torso across the pelvis to facilitate arm movement in a sagittal plane
Moves arm and rests hand on the surface away from the switch
Moves arm away from the switch using humeral flexion and horizontal adduction; humeral extension is used to lower arm to the table surface
Tapping under the humerus to facilitate shoulder flexion and elbow extension; tapping on the lateral border of the arm to facilitate horizontal adduction; forward then medial weight shift of torso across the pelvis to facilitate arm movement in a sagittal then lateral plane
use of Jodie’s right upper extremity for single switch activation working from her wheelchair. Although Jodie does have significant limitations in postural control, note that postural elements are woven into the treatment but are not identified as long-term goals. THERAPY ENVIRONMENT The therapist chose to intervene with Jodie in her classroom. The first-grade classroom was broken up into areas, meaning that there were times when floor space was available for therapy with Jodie out of her wheelchair. The therapist brought a therapy bolster to use during sessions. Being in the classroom meant that the same physical setup of the switch and computer was available for practice in a real-life situation in which the therapist could observe Jodie’s progress. Classmates were present, as was the case during spelling class, and could be available to provide encouragement if approved to do so by the classroom teacher.
HANDS-ON TREATMENT The therapist used four premises upon which to base her treatment. First, tone increases seen in Jodie when she attempts to use her upper limbs will be altered through the use of work on a mobile surface (the bolster), facilitation of forward and lateral weight shifts when reaching for her switch, and use of periodic rapid oscillations to the upper limbs. Second, use of facilitatory tapping and activeassisted hand placement on the switch will be used to help Jodie activate shoulder movements for hand placement, switch depression, and switch release (see Table 16-2). Third, practice of the task will be used to ensure changes in motor performance, motor learning of the skill being developed, and switch activation for computer use. Fourth, tactile enhancement and reinforcement will be used to ensure that Jodie knows when her hand is and is not on the switch to help build anticipatory control mechanisms needed for successful task accomplishment.
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BOX 16-2
Long-Term Goal and Benchmarks for Jodie
Jodie will be able to depress and release a 4 × 6 computer switch attached to a computer-scanning program in order to participate in spelling tests with her classmates a. Jodie will be able to lift and place her hand on the switch accurately 80% of the time. b. Jodi will be able to depress the switch to activate a simple on-off toy or object such as a radio 90% of the time c. Jodie will be able to depress and release the switch to participate in a simple computer game with 80% accuracy d. Jodie will be able to activate the switch with sufficient timing and accuracy to complete a 10-word spelling test within a 30-minute period of time e. Jodie will maintain her accuracy at switch activation through out the school day with minimal fatigue
TREATMENT IMPLEMENTATION In this section, sequencing within therapy sessions is described, incorporating the physical environment, therapy equipment, therapeutic facilitation, and practice components. Tone Management and Preparation for Activity Jodie was removed from her wheelchair for the first 15 to 20 minutes of each 40-minute session. This enabled the therapist to use weight shifts and techniques to modify the dynamic muscle tone Jodie demonstrated whenever she tried to use her upper limbs and gave her practice in use of appropriate postural components. A bolster was used because it enabled the therapist to use two planes of motion: anterior/posterior movements and lateral movements. Jodie was placed on the bolster, either on the far end or straddling it, to enable the therapist to use the movement of the bolster when addressing Jodie’s muscle tone during activities and to facilitate her active weight shifts while providing a wide base of support. These bolster motions were activated by the therapist’s use of her own lateral weight shifts and anterior or posterior body movements. At the same time, rapid oscillations of Jodie’s upper limbs were used to help loosen her stiff arms in preparation for developing the active shoulder movements needed to activate the switch (Figure 16-1). At this point, the therapist had Jodie lean onto her upper limbs positioned on the bolster to help inhibit tone and increase range in her hands as preparation for switch activation. Forward weight shifts accompanied the upper extremity weight bearing, passively accomplished at first by the therapist leaning forward into Jodie’s torso and moving her forward. The therapist facilitated the weight shift in
Figure 16-1 Jodie is seated on a bolster with the therapist behind her. The therapist supports Jodie’s arms at the elbow or slightly below, and moves them in a rapid alternating, up-and-down sequence to reduce muscle tone. The hands can be clapped against each other to assist. The therapist can move the bolster side to side with her own body if needed, and can lean forward to facilitate more trunk extension on the part of the child.
this manner for the first few times, and then used decreasing assistance as Jodie exhibited the ability to activate a weight shift on her own. Switch Activation This skill was practiced first with Jodie still on the bolster. Using the bolster allowed the therapist to facilitate weight shifts and shoulder movements and inhibit hyperextension of the trunk during efforts at movement. An adjustable height table under which the bolster was slid helped to support the switch. The switch position at first was put further back on the table than needed to require an exaggerated forward weight shift to counterbalance the extensor thrust that occurred when Jodie tried to move. Remember at this point that Jodie’s arms were resting on the table surface at midline so she would not have to move her shoulder high or far laterally to place her hand on the switch. The switch surface could be enhanced with a number of different materials (e.g., carpet samples, various fabrics) to heighten differences between the table and switch surfaces. When Jodie was asked to activate the switch, a series of short taps under her humerus were used to activate humeral flexion (Figure 16-2), then laterally to bring the humerus to the switch, which was placed slightly off to the side (Figure 16-3). Active assistance in placing her hand was also used alternatively to help Jodie develop a sense of what was needed to get to the switch; however, this only occurred on alternate attempts rather than each time she tried to touch the switch.
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Figure 16-2 Jodie has been asked to activate the switch but is demonstrating delayed response time. To assist her, the therapist sweep taps on the dorsum of her arm, moving from the elbow back toward the shoulder. The purpose is to give tactile input so that Jodie recognizes which body part needs to be moved.
Placing her hand on the switch and activating the switch were skills that were separated on the goal list but not in treatment. At this early point in learning to activate the switch, the switch was attached to a device such as a radio or fan, items that do not require a great deal of accuracy for successful activation. Once Jodie had her hand on the switch, a tap on either the volar surface of the humerus or the forearm was used to facilitate activation. An assisted weight shift posteriorly helped with switch activation as well, but it needed to be carefully carried out so that Jodie was not pulled backward. Active assistance was used to press the switch, using the same careful guidelines described earlier. A latch switch was used to limit the amount of time the device is active, requiring Jodie to lift her hand from the switch, then depress it again to restart the device. Releasing the switch was facilitated by incorporating the same techniques used to facilitate placing Jodie’s hand on the switch only in reverse order. Release of objects is a more challenging task for children with CP, as indicated by research in children with hemiplegia (Eliasson & Gordon, 2000; Gordon et al., 2003). Such studies have shown that the temporal aspect of release is a particular problem, which was the case for Jodie when releasing the switch. SEQUENCING THE PLAN The idea was to move Jodie forward in her treatment plan as expeditiously as possible. To do this, she needed to
Figure 16-3 A continuation of sweep tapping is used here; however, the direction has altered. The switch is placed about 15 degrees off of midline and Jodie needs to horizontally abduct her shoulder to hit her target. While the palm of the therapist’s hand remains under Jodie’s arm, the tips of her fingers are on the medial border of the arm and tap lightly to cue the change in movement direction.
practice outside of her therapy sessions. Ideally this would occur in both home and school settings, depending on the family and time in the classroom. Another way to manage more practice would be to increase the frequency and duration of treatment sessions. Although this program was developed around the traditional weekly model of therapy frequency, research has demonstrated that massed or intensive practice such as is used in constraint-induced paradigms and other research has better outcomes for children with CP (Duff & Gordon, 2003; Taub et al., 2004). Another critical issue was communication between the therapist and teacher. This assisted in documenting goals and assuring that teacher, aide, and therapist were all using similar techniques and the same equipment. If progress was not seen in a short period of time (2 to 3 weeks), then it would be necessary to re-evaluate the plan and adjust intervention. OUTCOME It was soon apparent that the switch needed to be stabilized on the surface; therefore a slightly inclined easel surface with Dycem under the switch and easel were used to provide stability. Masking tape was used on both home and school table surfaces to mark where the easel went to be sure that the location of the switch was consistent over time.
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Jodie made rapid progress at placing her hand on the switch. Accurate depression and release of the switch volitionally in a timely fashion took another 2 to 3 months to achieve with frequent dialogue among teachers, therapist, and family. Jodie was motivated, which helped, and had persistent encouragement from her classmates. Her switch activation accuracy initially deteriorated throughout the
day as fatigue set in, so the family limited her home practice to weekends. At the end of 3 months, Jodie could accurately complete a 10-word spelling assignment using hand-activation of her switch in 30 minutes. Fatigue was becoming less of a factor, so her teacher began to add short assignments later in the day.
CASE STUDY 2 A C HILD WITH LOW TONE Two-and-a-half-year-old Lily has quadriplegic involvement with low muscle tone and aimless movements of her limbs. She can hold her head up and sit for short periods of time (3 to 5 minutes) when placed in supported sitting but spends much of her day playing in prone or supine, or propped in her infant seat. She can grasp objects with either hand but does not use both hands together. Most of her activity consists of mouthing objects and then dropping them after briefly holding onto them. Her mother reports her as being an irritable child who screams when new stimuli come into the environment. The family would like her to be able to play by herself for longer periods of time and use both hands to play, to sit up longer so they can play with her, to hold her cup and drink from it, and for her to be less irritable. Box 16-3 contains examples of goals for Lily. The goals of using her hands to hold a cup will be used for demonstration purposes. Specifically the goal will be for Lily to sit supported in her high chair and lift her cup and drink when it is placed on a surface in front of her. Table 16-3 shows an activity analysis of this goal, which is used to plan the intervention. PREPARATORY ACTIVITIES The intervention was scheduled for Lily’s usual afternoon snack time to locate the intervention in her usual daily pattern of activities. Doing so offered demonstration time and consistent feedback to the mother about Lily’s performance and gave the therapist the opportunity to reevaluate Lily’s skills each week. Table 16-4 illustrates the steps of the activity and the techniques to be incorporated into the intervention session. Because Lily was anticipating the cup, she tended to be less tolerant of extensive prefeeding activity, so preparatory work was limited to 5 to 10 minutes. The therapist sat on a chair or sofa. Lily was positioned on the therapist’s knees; she could either face the therapist or face her mother with her back to the therapist. Facing the therapist meant her base of support was wider because she was straddling the therapist’s legs; while facing her mother she was not straddling and the base of support was narrower. Lily was supported at the shoulders and the therapist gently bounced her using
BOX 16-3
Long-Term and Short-Term Goals for Lily
1. Lily will lift the cup from the surface to her mouth a. Lily will place both hands on the cup when it is placed on the surface in front of her. b. Lily will lift an almost empty cup off of the surface briefly. 2. Lily will hold the cup when it is placed at her mouth to take a drink. a. Lily will place both hands on the cup while mother provides over hand assistance. b. Lily will spontaneously place her hands on the cup held at her mouth for a few second. c. Lily will hold an almost empty cup at her mouth with minimal assistance from her mother. 3. Lily will put the cup back on the surface after she has drunk from it. a. Lily will maintain her hands on the cup with maximal assistance from her mother as her mother returns it to the surface. b. Lily will hold the cup briefly when she is finished drinking and then place it. 4. Lily will lift the cup to her mouth, drink from it, and return the cup to the surface.
plantar flexion and return from plantar flexion of her own feet to provide bounces that were timed asymmetrically so as not to be predictable. Firm downward pressure was applied at the shoulders, with the therapist’s thumbs positioned over the heads of each humerus and the fingers supporting the scapulae (Figure 16-4). Sound production by Lily was encouraged to activate abdominal contraction at the same time. This activity was sustained for 1 to 2 minutes, and then the therapist’s hand position was shifted
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Table 16-3
Activity analysis of drinking from a cup with two hands in supported sitting Visual Component
Auditory Component
Movement Components
Tactile Component
Cup is placed on surface; child’s arms activate at the sight of the cup
Sees cup approaching and set on surface
Person handing the cup may make statement; cup makes sound as it touches the table
Arms move toward the cup; possible components: humeral abduction moves to humeral adduction; elbows extend and hands open
Kinesthetic feedback from the limb moving
Takes cup
Sees the cup held at midline
Parent may make statement
Hands grasp cup; humeri are adducted, elbows midway between flexion and extension and forearm midposition, fingers flexing
Lily feels the cup on her hands; weight of the liquid gives proprioceptive feedback
Raises cup to her mouth
Sees the cup moving toward her face
Humeral movement is flexion; elbows move into flexion; fingers flexed
Feels cup touch her mouth; feels weight of cup on hands and through shoulders
Drinks from cup
May look at others in the room
Humeral and elbow flexion used to lift the cup to pour liquid into the mouth
Feels weight of the cup in her hands, and liquid in the mouth and throat
Brings cup back to surface and releases it
May look at cup as she moves it away from her mouth
Humeri and elbows extend
Feels cup hit the surface and absence of tactile feedback on her hands
Step of Activity
Hears cup when it hits the table
to Lily’s abdomen and lumbar spine. The hand on the lumbar spine was for support, whereas the hand on the abdomen was used to apply firm downward pressure to continue activation of the abdominals. A movement transition to produce coactivation of trunk extensors and flexors followed. Lily was weight shifted toward the arm of the chair with the key point of control at the pelvis. The goal here was for Lily to put both hands onto the chair arm, producing a bilateral upper limb weight-bearing activity (Figure 16-5). The pelvis was
maintained in a straight plane position while the trunk rotated over it, a position requiring cocontraction of abdominals and trunk extensors. This activity was carried out briefly, and then Lily was facilitated to turn to face her mother with the therapist’s hands moved back to the abdominals and lumbar spine and downward pressure applied on the abdominals to activate a forward weight shift. Her mother facilitated bilateral shoulder flexion by holding her hands out to Lily. She did not pick up her daughter until Lily reached out with both arms. The
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Table 16-4
Facilitation and inhibition techniques to be used in Lily’s treatment
Step of Activity
Movement Components
Facilitation/Inhibition Techniques
Cup is placed on surface; child’s arms activate at the sight of the cup
Arms move toward the cup; possible components: humeral abduction moves to humeral adduction; elbows extend and hands open
Deep pressure on the abdominals to facilitate trunk and humeral movements toward midline; humeri as key point of control to bring hands together passively then as cue to do so actively; Hands clapped together to give sensory cue to open hands and deep pressure feedback to palms of hands.
Takes cup
Hands grasp cup; humeri are adducted, elbows midway between flexion and extension and forearm midposition, fingers flexing
Anterior weight shift to assist in reaching for and grasping the cup; hands brought to the cup and deep pressure on hands over the cup used to give sensory feedback; approximation through the trunk to facilitate co-contraction of abdominals and extensors
Raises cup to her mouth
Humeral movement is flexion; elbows move into flexion; fingers flexed
Shoulders used as a key point of control to sustain hands on the cup; ulnar side fingers used to tap under the arms to facilitate forward flexion; posterior weight shift used to facilitate arms to lift.
Drinks from cup
Humeral and elbow flexion used to lift the cup to pour liquid into the mouth
Posterior weight shift to facilitate neck flexors and abdominals to hold with head and trunk extended while drinking; shoulders continue as key point of control for entire upper limb
Brings cup back to surface and lets it drop
Humeri and elbows extend
Anterior weight shift to assist in reach of arms to the tray; gentle vibration to facilitate fingers letting go of the cup.
movement transitions described provided limited vestibular input. More consistent use of rotary movements during transitions provides the kind of vestibular input children achieve themselves through active movements. ACTIVITY PRACTICE OF DRINKING FROM THE CUP Lily was placed in her child-sized chair. The therapist sat behind the high chair and placed her hands on Lily’s shoulders. The thumbs were placed along the proximal aspect of the humerus and the fingers rested on the abdomen. Her mother held a half-filled cup in front of Lily but did not place it on the tray. The therapist used pressure on the lateral border of the humeri to bring Lily’s hands together and then slipped her hands up over the proximal part of her arms to help Lily clap her hands firmly several times. Her mother then placed the cup on the tray, tapping it to get Lily’s attention and asking her to take the cup. A subtle forward weight shift for the reach was facilitated using the shoulders as a key point of control. Her mother cued her verbally again and the therapist waited briefly to see if Lily reached for the cup,
then helped place her hands on it. Firm pressure on the shoulders was attempted to sustain Lily’s hands on the cup. When unsuccessful, the therapist slid her hands down over Lily’s hands (Figure 16-6). Once Lily sustained her grasp of the cup, tapping under the proximal aspect of the arm was used to facilitate lifting. As Lily became more proficient at grasping, the therapist moved her hands back up to the child’s shoulder to help facilitate lifting and holding of the cup at the mouth. With further progress, the therapist gradually withdrew her support, limiting the cues needed to generate Lily’s participation. The mother could facilitate this activity from in front of Lily in a sitting position using the same key points and sequence of activity. The preparatory activities were taught to the mother as a game to be carried out at different times during the day, as well as in preparation for feeding. OUTCOMES Lily actively resisted the movement transition sequence. After attempting to use it before giving Lily her cup, the therapist chose to discontinue this aspect of the inter-
Upper Extremity Intervention in Cerebral Palsy: A Neurodevelopmental Approach • 363
Figure 16-4 Lily is positioned on the therapist’s knees facing the therapist. She is supported at the shoulders and the therapist is gently bouncing her, using her own feet to provide the bounces. Firm downward pressure is applied at the shoulders, with the therapists’ thumbs positioned over the heads of each humerus and the fingers supporting the scapulae.
vention and worked on two-handed reach and grasp of the cup only. Lily was able to reach and grasp with two hands successfully in several weeks. Her ability to keep two hands on the cup while bringing it to her mouth took another month. Lily still refuses to grasp the cup on occasion when irritable.
Figure 16-5 A movement transition to produce coactivation of trunk extensors and flexors is illustrated here. Lily’s weight is shifted toward the arm of the chair with the therapist’s key point of control at the pelvis. The pelvis rotates slightly and one side lifts with the weight shift while the trunk rotates over it. At the same time, Lily moves her hand to the arm of the rocking chair to support herself, producing a weightbearing activity in conjunction with a movement transition.
Figure 16-6 In this figure, the child is having difficulty sustaining her grasp on the surface of the cup. To cue her, the therapist places her hands over Lily’s and applies gentle pressure over Lily’s wrists and hands to support the cup and give her sensory feedback about the task. As Lily becomes more proficient, the therapist can slide her hands back up the forearms to guide the movement while Lily maintains her grip on the cup independently.
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anticipatory postural adjustments during whole body forward reaching movements. Neuroreport, 9:395–401. Steenbergen B, Hulstijn W, Dortmans S (2000). Constraints on grip selection in cerebral palsy: Minimizing discomfort. Experimental Brain Research, 134:385–397. Strauss D, Shavelle R (1998). Life expectancy of adults with cerebral palsy. Developmental Medicine and Child Neurology, 40:369–375. Strauss D, Cable W, Shavelle R (1999). Causes of excess mortality in cerebral palsy. Developmental Medicine and Child Neurology, 41:580–585. Thomas SS, Buckon CE, Phillips DS, Aiona M, Sussman M (2001). Interobserver reliability of the gross motor performance measure: Preliminary results. Developmental Medicine and Child Neurology, 36:97–102. Taub E, Ramey SL, DeLuca S, Echols K (2004). Efficacy of constraint-induced movement therapy for children with cerebral palsy with asymmetric motor impairment. Pediatrics, 113(2):305–312. Trahan J, Malouin F (2002). Intermittent intensive physiotherapy in children with cerebral palsy: A pilot study. Developmental Medicine and Child Neurology, 44:233–239. Tsorlakis N, Evaggelinou C, Grouios G, Tsorbatzoudis C (2004). Effect of intensive neurodevelopmental treatment in gross motor function of children with cerebral palsy. Developmental Medicine and Child Neurology, 46:740–745. Turk MA, Geremski CA, Rosenbaum PF, Weber RJ (1997). The health status of women with cerebral palsy. Archives of Physical Medicine and Rehabilitation, 78:10–17. Van der Heide J, Begeer C, Fock JM, Otten B, Stremmelaar E, van Eykern L, Hadders-Algra M (2004). Postural control during reaching in preterm children with cerebral palsy. Developmental Medicine and Child Neurology, 46:253–266. Vogtle L, Snell ME (2004). Methods for promoting basic and instrumental activities of daily living. In C Christiansen, editor: Ways of living: Self-care strategies for special needs, 3rd ed. (pp. 85–108). Rockville, MD, The American Occupational Therapy Association. Volman MJ, Wijnroks A, Vermeer A (2002). Effect of task context on reaching performance in children with spastic hemiparesis. Clinical Rehabilitation, 16:684–692. Yekutiel M, Jariwala M, Stretch P (1994). Sensory deficit in the hands of children with cerebral palsy: A new look at assessment and prevalence. Developmental Medicine and Child Neurology, 36:619–624.
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PEDIATRIC HAND THERAPY Dorit Haenosh Aaron
CHAPTER OUTLINE PHASES OF WOUND HEALING Phase I Phase II Phase III EVALUATION OF THE CHILD WITH A HAND INJURY Interview and History Hand Range of Motion Hand Strength Hand Dexterity Wound, Edema, and Scare Pain Hand Sensibility Activities of Daily Living TREATMENT OF TRAUMATIC HAND INJURIES IN CHILDREN Wrist Pain and Wrist Fractures Fractures and Dislocations of the Digits Tendon Injuries Thermal Hand Injuries in Children TREATMENT OF CONGENITAL HAND DIFFERENCES Syndactyly Radial Club Hand SUMMARY Observing a child at play makes it easy to understand why the hand is one of the most frequently injured body parts. Children must touch what they see and, if the mind can conceive it, the hand will attempt it. The hand is the primary instrument of discovery. Although discovery is a function of the mind, it involves the eyes,
torso, shoulder, elbow, wrist, and hand to accomplish a task. Scientific evidence on pediatric hand rehabilitation is sparse. Thus this chapter is based primarily on the author’s clinical experience. Additional information is included when available. Hand conditions are challenging in and of themselves. When they occur in a child, consideration must be given not only to the pathology, stages and rate of healing, and functional implications, but also to the stage of development. When treating a child attention must be given to the child’s age, growth, maturity, ability to participate in his or her own recovery, as well as parental or guardian involvement. These additional considerations make treating the child rewarding, as well as challenging. The child’s hand differs from adults’ in that it is a growing hand of a developing child. The growing hand changes rapidly in its physical size, manipulation skills, strength, and control; as does the child’s ability to follow directions and participate in rehabilitation. Injuries to growth plates may affect the way the child’s bone grows in length and direction. Fat pads may obscure swelling. Congenital differences may affect any structure of the hand and thus influence function. Therefore, when treating the child with a congenital difference, determine what the child can do at present and identify realistic expectations for the individual, rather than focusing on what the child cannot do or comparing the child to the general population. In general, children have a better prognosis for recovery from hand injuries than do adults. Stiffness is less frequent, open wounds heal faster, remodeling of angular deformities may occur, and nerve recovery after repair is significantly better than for adults (Davis & Crick, 1988). Fetter-Zarzeka and Joseph (2002) examined the etiologies of hand injuries in children and concluded that the most frequent injuries occurred outdoors (47%), injuries occurred specifically from sports, and the most frequent injuries were lacerations
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(30%) followed by fractures (16%). The fingers were the most commonly injured part of the hand, with thumb injuries found in 19% of the cases and fingertip injuries found in 21% of the cases (Fetter-Zarzeka & Joseph, 2002; Damore et al., 2003). Most pediatric hand and wrist injuries can be treated nonoperatively with protective immobilization and activity modification. However, cases that require surgical intervention must be recognized early to avoid complications (Le & Hentz, 2000). The goal of this chapter is to provide basic information to therapists to facilitate effective evaluation and treatment for hand conditions occurring in pediatric patients. This chapter covers the stages of wound healing and evaluation considerations by age as the baseline for making clinical decisions. Evaluation and treatment suggestions for common traumatic and congenital hand conditions in the child also are included.
PHASES OF WOUND HEALING Treatment and decision making during the healing phase of wounds must be based on the stage of healing, as well as on the age of the child. After injury, all tissues undergo a similar process of repair. Injury to vascular tissue initiates a series of responses collectively known as “inflammation and repair.” Regeneration is possible only in tissue that is capable of proliferation of the remaining cells (normal tissue). Repair is the replacement of destroyed tissue with scar tissue. Both regeneration and repair begin during inflammation with phagocytosis of dead tissue cells. The ultimate goal of these responses is to eliminate the pathologic or physical insult, replace the damaged tissue, promote regeneration, and thus restore function. Inflammation is the first (acute) phase of healing. When unresolved, it may go through two more stages: Acute: Usually completed by day 6; normal healing. Subacute: Reaction continues for up to 1 month, same as acute stage on a cellular level. and is treated the same clinically. Chronic: Simultaneous progression of active inflammation, tissue destruction, and healing. It varies from acute on a cellular level and lasts beyond 1 month. Normal tissue is replaced by scar (Pryde, 2003). The most common causes of an inflammatory response are burns, fractures, cuts or crush injuries, and soft-tissue injuries such as sprains, strains, or contusions. Inflammation also can be caused by the presence of foreign bodies, autoimmune diseases such as rheumatoid arthritis or chemical agents (Pryde, 2003). Healing requires increased metabolic activity. Blood supply to the site of the lesion must remain increased
for continued oxygen, glucose, and protein supply. Ischemia interferes with wound healing (Evans & McAuliffe, 2002). Although variations are reported in the literature, tissue healing is most commonly summarized in three phases.
PHASE I Names: Inflammatory, Clot, Substrate, Lag, or Exudates Phase Duration: From Wounding Up to 6 Days Phase I prepares the wound for healing by cleaning up debris, foreign material, and any devitalized tissue caused by the trauma. It has both vascular and cellular responses. Initially there is vasoconstriction followed by vasodilatation. A clot is formed to prevent bleeding and phagocytosis begins. The normal inflammatory phase should be over in 5 to 6 days. However, a dirty wound, in which the debris was not successfully cleaned up, may develop into a subacute or chronic phase of inflammation.
Clinical Signs Redness: Vasodilation Swelling: Increase of interstitial fluid Pain: Nerve ending stimulation Heat: Increase in blood flow Hematoma: Trapped red blood cells creating a clot decrease functional ability
Clinical Implications The extremity is swollen and painful. Thus effort must be made to decrease edema, control pain, and maintain a clean environment. All affected joints should be placed in a functional position if possible. The functional position is one in which the wrist is in neutral to 20 degrees of extension, the metacarpophalangeal joint (MP) is in 60 to 70 degrees of flexion, the interphalangeal joints (IPs) are extended, and the thumb is in mid position between full abduction and full extension. Variations of this position depend on the injury. This position must serve to both protect the wound and to prepare the joint for future functional performance. Nonaffected joints should be free to move within the constraints of the injury. Physical agents can be used. An edematous hand in the early phases of inflammation responds to cold to help decrease the swelling. Cold constricts the vessels, slowing down the active edema process; however, it is rarely appropriate for the infant or toddler. For the older child, physical agents must be selected carefully to enhance healing. At later phase heat might be the modality of choice for the same result. Heat dilates the vessels. When the hand is placed in elevation with
Pediatric Hand Therapy • 369 slight pressure, the stationary edema is guided back to the body. If used in Phase I, heat increases swelling. A whirlpool may be used for debridement of open wounds. The temperature of the water should be tepid, and if possible the hand should be positioned at heart level.
balance between laying down collagen and getting rid of debris (synthesis versus lysis), occurs in a balanced fashion. However, when this balance is tipped, it may become pathologic, which may result in the following: • Contraction of the scar • Hypertrophic scar: Within wound boundaries • Keloid: Outside wound boundaries
PHASE II
Clinical Signs and Considerations
Names: Fibroblastic, Proliferative, or Latent Stage Duration: Variable, but Usually 5 to 21 Days, Can Last Up to 6 Weeks
Scarring may affect function and aesthetics Movement limitations may be present Pain may continue to be problematic Tensile strength (see below) of tissue is still increasing, but remains below normal Functional use of the extremity that is involved is encouraged in activities of daily living (ADLs) Contextual implications are considered in treatment planning
The purpose of this stage is to rebuild damaged structures, and cover and strengthen the wound. There is migration and proliferation of vessels for tissue repair. Primitive healing occurs. The wound begins contracting from the outside in. This migration of cells is limited by tension. Oxygen is needed for the healing process. Four processes occur simultaneously in this phase: epithelization, collagen production, wound contraction, and neovascularization.
Clinical Signs Red granulation tissue Beginning of wound contraction: Scars appear faster in children than adults. Moderate swelling may be present Pain: Variable Functional limitations
Tensile Strength of Tissue Tensile strength is the ability of a structure to withstand a pulling force along its length or resistance to a tear. Scar tissue is not as strong as the normal tissue it replaces; however, the volume of the scar influences its strength. Unfortunately, the more volume the scar has, the stronger the scar and the less motion when the scar crosses a joint. Tensile strength of the scar increases with increased collagen and each phase of healing. As mentioned, tensile strength reaches 50% of normal strength of the skin by 6 weeks (Smith, 1992).
Clinical Implication Clinical Implications The clinical focus in Phase II is on decreasing scarring and increasing mobility. Scar management is a challenge with children. If pressure garments are indicated, the therapist may prefer to order a pressure garment that covers more than just the hand to keep the garment on, and to allow even pressure throughout the small body area. At the same time, motion must be encouraged. With children, immobilization may extend a week or two beyond the normal protocol if the repair needs to be protected. Children regain motion rapidly when presented with “play” situations after immobilization. Balancing immobilization and mobility requires individual decisions based on the child’s age and level of maturity and severity of injury.
PHASE III Names: Maturation, Scar Remodeling Duration: End of Fibroplasia to 2 Years In this phase, connective tissue matrix is remodeled. Wound strength (tensile strength) may reach 50% of normal by 4 to 6 weeks. Remodeling, which is a
When healing reaches Phase III, the rehabilitation program should concentrate on returning the child to full play and activity. Therapeutic activities must stay under the “breaking strength” of the scar, which is the amount of force it takes to bring the wound apart. How much tension one places on a wound varies with each stage of healing, type of injury, and age (Mulder & Brazinsky, 1995). Modalities such as splinting, physical agents, strengthening exercises, and other therapeutic interventions should focus on the functional needs rather than the functional limitations of the child. Box 17-1 shows the three phases of wound healing.
EVALUATION OF THE CHILD WITH A HAND INJURY Evaluation of the child differs from that of the adult. Specifically, the age of the child determines what the “hand is expected to do.” The infant who does not yet cross midline with hand performance differs from the adolescent. A toddler who brings everything to the
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BOX 17-1
Phases of Wound Healing
PHASE I Vasoconstriction Vasodilation Clot formation Phagocytosis PHASE II Epithelization Collagen production Primitive wound contracture Neovascularization (O2) PHASE III Maturation of scar Collagen synthesis versus lysis Collagen fiber orientation and wound strength
the therapist may wish to obtain information in the following areas.
I NTERVIEW AND H ISTORY When a child comes to therapy, a thorough review of the child’s medical, family, emotional, educational, and social history should be obtained from the family and the child, when possible. Information from the doctor should include precautions relevant to the healing of the injury or surgery, as well as all relevant information about the surgery and medical management. A prescription from the doctor should be clear about the expectations for function. If a child is referred for a splint alone, information must be obtained about how long the body part is to be immobilized.
HAND RANGE OF MOTION mouth differs from the teenager who can understand and follow directions. Both evaluation and treatment must reflect the age and developmental level of the child, as well as the injury or condition of the hand. Performance assessments such as dexterity tests cannot be given to a newborn but can be administered in a modified way to a toddler, and given in a standardized way to an adolescent. The goal of an evaluation is to determine the realistic functional abilities of the child at the initiation of therapy and document progress. Realistic goals are set by the child when possible, as well as by the parents or guardians and therapist. The evaluation process must be dynamic and flexible. Information about the child’s ability to use the hand, pain level, and specific restriction of motion may be gathered through play, general observations, or specific assessments. Significant information can be gathered from parental reports and interviews. Creativity in encouraging a child to use an injured hand is part of the challenge of a good evaluation. Photographs and videotaping for later specific assessment of the child’s play patterns may be helpful. In hand therapy, evaluation requires an initial determination of impairment level followed by its influence on the functional levels as they apply to the child’s developmental stage. The child’s hand performance in life roles changes with growth. Shortridge (1989) describes growth periods in estimated age levels that must be considered during evaluation. After traumatic injury or surgery the quality, speed, and direction of the healing, as well as the age of the child, are considered. With congenital differences, evaluations must be relevant to realistic expectations for both the age and diagnosis. The specific assessments in a hand evaluation are determined by the diagnosis, phase of healing, and age of the child. While not losing sight of functional goals,
Hand range of motion (ROM) is important for functional activities such as picking up and manipulating objects, as well as touching and feeling. Total upper extremity ROM is important in reaching into the environment. When measuring hand ROM, the therapist also looks at total upper extremity movement, as well as trunk and neck mobility. The hand is not separated from the body in activity and therefore should not be separated in evaluation. When evaluating ROM in a hand injury or condition, close attention is given to tissue that obstructs the motion. Ranges are reported, when possible, in several ways so that the source of the limitation may be identified. Passive range is the available motion intrinsic to a joint when all extrinsic limitations are minimized. If a tendon or scar is limiting the joint motion, place the joint in a position of maximum biomechanical advantage when measuring passive range so as to eliminate the extrinsic factors (Figure 17-1). For example, if the flexor tendons are tight, flex the wrist when measuring passive MP motion. Conversely, when measuring active motion, information is gained about the extrinsic structure that may be limiting joint motion. Active motion may be divided into functional motion, the motion available when the child is asked to make a fist or open the hand with no limitations or instructions (Figure 17-2) versus blocked motion, which refers to the motion available when all proximal joints are put in neutral (biomechanical advantage) to allow maximum force to be applied to elicit the available motion of the joint being measured (Figure 17-3). For example, if measuring blocked proximal interphalangeal (PIP) flexion in a child with a flexor tendon injury, put the wrist and MPs in neutral and ask the child to flex his or her fingers. This provides informa-
Pediatric Hand Therapy • 371
Figure 17-1
Passive range of motion (PROM).
Figure 17-3
Figure 17-2
Active range of motion (AROM).
tion about flexor tendon excursion. Placing the proximal joints in slight extension gives the flexors more advantage. Always record where the proximal joint(s) were placed during blocked measurements, so that measurements can be repeated reliably. Finally, compare all ranges to determine which structure is limiting
Blocked range of motion (BROM).
the motion. Reliability of ROM is based on repeatability. The American Society of Hand Therapists (1992) published a Clinical Assessment Recommendation booklet that is an excellent resource for standardization of measurements (Adams, Greene, & Topoozian, 1992). Scheduling constraints and the child’s cooperation at times may limit the therapist’s ability to take comprehensive measurements. On these occasions, functional measurements can be recorded. These measurements have poor reliability because they are difficult to reproduce consistently. However, they do give some functional information about the use of the hand and thus have value in some cases. Functional measurements include: Functional Flexion: (a) Ask the child to make a fist; measure the distance from the pulp of the digit(s) to the distal palmar crease (Figure 17-4); or (b) ask the child to make a hook, bringing the tips of the fingers to the palmar digital crease; measure that distance. Functional Opposition: Ask the child to touch the tip of each finger to the thumb; measure the distance from pulp of finger to pulp of thumb (Figure 17-5). Functional Thumb Flexion: Ask the child to touch the base of the small finger with the thumb, measure the distance from the head of the 5th metacarpal to the pulp of the thumb (Figure 17-6). Functional Extension: Ask the child to extend the hand against the table; measure the distance from the nail to the table top (Figure 17-7).
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Figure 17-6 Functional thumb flexion to the base of the fifth finger. Figure 17-4 crease.
Functional flexion to the distal palmar
Figure 17-7 Figure 17-5
Functional extension to the table top.
Functional opposition.
Toddlers (12 to 48 Months) Newborns and Infants (Up to 12 Months) ROM is assessed mainly through observation. The therapist must pay close attention to the movement in the whole upper extremity. The therapist looks for shoulder movements, elbow range, and opening and closing of the hand. The child is encouraged to move through touch, sound, gentle handling, and reflex stimulation such as the startle response. Movements should be compared with the uninvolved side when possible.
ROM can be measured in the upper extremity, but it is difficult in the hand itself. Motion is encouraged through play. The child should be given objects that range in size and weight to determine grasp and release patterns. Sustained and volitional grasp should be observed. Colorful objects or familiar designs are helpful. The child should be encouraged to place objects in different locations so that reach and precision can be examined. ROM at this age is documented more in patterns of prehension and usage rather than degrees of motion. For those situations in which handling of
Pediatric Hand Therapy • 373 objects is not advised because of the stage of healing, the therapist may encourage movement through reach or gentle touch of sterile objects. Parents’ reports and observations can be helpful with this age group.
Childhood (5 to 12 Years) Measurement of specific range can be obtained at this age, although it may be difficult. Observation of movement patterns that are consistent with in-hand manipulation that are present at this stage are helpful (Exner, 1992). The child can be asked to hold a spoon or turn over a peg of a certain size in the hand, which provides both functional and range information.
Adolescence (13 to 18 Years) ROM in the adolescent and the older child can be specific to joint and degrees of motion. Members of this age group can follow directions. Their hands are large enough for goniometer placement and measurement of individual joints.
Figure 17-8 strength.
Dynamometer used to measure grip
Figure 17-9
Pinch gauge to measure pinch strength.
Clinical Implication ROM helps determine which structure is the source of the limitation. This information comes from measuring the difference between passive and active motion, checking for unusual patterns such as intrinsic, web, and ligamentous tightness. Active motion can be divided into two types: (a) functional motion, motion the child does on his or her own; and (b) blocked motion, motion produced when the proximal joints are held in a position that gives maximum advantage to the distal joint. The difference between measurements tells the therapist where the problem exists.
HAND STRENGTH Hand strength is a function of the work of the muscles. In measuring hand strength, we look at both specific muscle strength and functional strength. Specific muscle strength is the measurement of each muscle tendon unit that is measured through manual muscle testing, whereas functional strength is a measure of muscles working together in a specific prehension pattern and is measured with instruments such as a dynamometer and pinch gauge. Functional measurements are divided into grip and pinch strength (Figs. 17-8 and 17-9). They are divided further into varying grip sizes and different pinch patterns. Most commonly tested pinch patterns are key pinch, pencil or three jaw chuck pinch, and pad to pad pinch. With the handinjured population, functional strength measurements are the most common. Although a variety of tools exist for measuring strength, the most common are a dynamometer for grip strength and a pinch gauge for pinch strength.
Newborn Through Early Childhood Hand strength as a measure in and of itself is not necessary for this age group. The therapist concentrates on functional use of the hand in age-appropriate activities. For children past infancy, activities such as handling toys, picking up utensils, and picking up objects of different weights with one or two hands provide the therapist with information on available strength for the age-appropriate activities. Enticing a child to move painful fingers is challenging. Young children like to perform, so one effective method is videotaping the child with the promise of watching his or her hands move on tape. Specific questions related to functional hand strength include the following: Does the child have sustained grasp? Does the child demonstrate volitional grasp?
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Middle Childhood to Adolescence The older child’s strength can be measured with conventional tools such as dynamometers and pinch gauges, or various available computerized instruments. Strength goals in treatment should be consistent with the demands for hand strength in the child’s life roles. When measuring hand grip in children, norms that reflect the appropriate age group and comparable instruments are used. Hager-Ross and Rosblad (2002) provide norms for children ages 4 to 16. They tested grip strength in 530 children using the Grippit instrument. They reported a parallel increase in grip strength for both boys and girls until age 10, after which boys were significantly stronger than girls. The study further suggests a correlation between hand size, specifically hand length, and strength. Right-handed children were significantly stronger in their dominant hand than lefthanded children. Left-handed children did not show any strength difference between the hands (Hager-Ross & Rosblad, 2002). Bear-Lehman and co-workers (2002) studied the relationship between grip size and strength in children and also concluded that strength, grip, and pinch increase with hand size, but they found no significant difference between males and females or preferred hands. In an earlier study, Mathiowets, Wiemer, and Federman (1986) reported dynamometer readings from 471 typical children ages 6 to 19 years. They reported pinch and grip strength increases with chronologic age. Mathiowets and co-workers (1986) noted possible instrument error after the study and concluded that reported norms for subjects ages 14 to 19 may be slightly lower than they should have been (Pratt et al., 1989). These studies suggest a trend of increasing strength with age and hand size. Caution should be exercised in using these norms unless the test instruments and conditions are the same. Manual muscle testing may be used for specific muscles for older children when indicated by the diagnosis. Large muscles, as well as the small muscles of the hand, should be tested. When rating muscle strength, the 0 to 5 scale may be used. Specific instructions are available in the literature on how to perform manual muscle testing (Aulicino, 2002). 0 = No evidence of contraction 1 = Trace of muscle contraction, no movement 2 = Complete ROM with gravity eliminated (poor) 3 = Complete ROM against gravity (fair) 4 = Complete ROM against gravity with some resistance (good) 5 = Normal ROM against gravity with full resistance
commonly used with hand injuries and conditions. However, at times specific manual muscle testing is indicated, especially with older children.
HAND DEXTERITY Dexterity as a component of function is described as the ability to manipulate objects with the hands. Accuracy and speed are the parameters of measurements for dexterity. Dexterity can be measured reliably through established tests that have normative data on the population tested. Dexterity may also be observed when the child is picking up different size objects and manipulating them (Aaron & Stegink Jansen, 2003).
Newborns and Infants Hand dexterity in the newborn is confined to reflexive opening and closing the hand and bringing the hands to the mouth. Such motions are determined through observation. In the newborn, stimulating reflexes such as Moro or hand grasp gives the therapist information on ROM and symmetry of movement patterns appropriate for this age.
Toddler Dexterity is determined by watching the child manipulate small objects. In-hand manipulation skills (moving an object within the person’s hand) is noted at this age. The therapist places a small object in the child’s hand and asks that it be turned over or moved around in the hand. Video recording of the manipulation complements the testing procedure.
Early Childhood Observation remains a staple of the evaluation procedure for this age group. The therapist observes how the child approaches small objects, which hand is used in grasp, grasp and release patterns, and sizes of manipulated objects. For more standardized testing, dexterity tests such as the Functional Dexterity Test (FDT) may be used. It is standardized for children ages 3 to 5 years (Aaron & Stegink Jansen, 2003; Lee-Valkov et al., 2003). For the age groups listed, the therapist observes for the following information: • Are tasks or activities performed unilaterally or bilaterally? • Is the hand being used spontaneously? • Is there indication of dominance? (Note: Hand dominance that appears too early may indicate a problem with the nonpreferred side.)
Clinical Implication
Adolescence
Appropriate methods of obtaining hand strength measurements vary according to the child’s age and ability to participate. Functional measures are most
Children in this age group have fine motor control and dexterity that can be tested using available standardized tests. Depending on what information the therapist
Pediatric Hand Therapy • 375 wants to obtain, the use of such standardized tests as the Box and Block Test or the Minnesota Rate of Manipulation may be used for information on dexterity (Apfel & Carramza, 1992). If information on ADLs is needed, specifically manipulation of small objects such as buttoning or tying, the Functional Dexterity Test (FDT) may be the test of choice because it gives information on both dexterity and function and can be administered in a short period of time (Aaron & Stegink Jansen, 2003) (Figure 17-10).
Clinical Implications Dexterity is a component of function that often is overlooked in a hand evaluation. Dexterity information is obtained by using standardized tests such as the FDT or through observation.
WOUND, E DEMA, AND SCAR When a child of any age has an acute injury, the therapist must document the appearance of the hand at each stage of healing. This includes describing the wound, measuring the edema, and describing and measuring the scar. Describe the wound and take a picture when possible. In the description of the wound, note such elements as: 1. Color a. Red Wound: Normal granulating tissue b. Yellow Wound: Wound covered by yellow fibrous debris or viscous surface exudates c. Black Wound: Wound covered with thick necrotic tissue or eschar 2. Size. Measure the size of the wound. Draw the actual size of the wound in the chart. Color in the different colors that you see.
3. Drainage. Note if there is any drainage. Use descriptive words such as “minimal, moderate, or severe” for the amount of drainage, and “bloody, sanguinous, purulent, pus” for the quality of the drainage. 4. Odor. An unusual odor may suggest infection or presence of foreign material. 5. Temperature. Compare the temperature of the hand or part to the other side. Warm or hot may indicate infection or inflammation, whereas cool or cold may point to a vascular insufficiency. 6. Edema. Edema should be noted throughout the healing process. Edema is measured with a tape measure or volumeter. If the wound is open, the tape measure must be sterile and the water in the volumeter must be treated with a disinfectant. When using a tape, landmarks are noted in the chart for consistency of measurement. The skin should not blanch when circumferential measurements are taken with the tape. When using the volumeter (a water displacement test), the hand is placed straight-in so as not to displace more water than necessary. The hand is lowered into the water until the web space between the long and ring fingers rests on the small peg at the bottom of the container. The volumeter usually is used with large edematous areas and with older children. Descriptive words, such as “hard, mobile, brawny, or pitting,” should be used for recording the type of edema. 7. Scar. Scar should be described as “soft, thick, raised, indurated, hard, or reactive.” Depth, length, and width of the scar should be measured and color and vascularity should be noted. Sensitivity (or lack of) of the scar should be recorded. Both a drawing and a photograph of the scar should be taken if possible (Baldwin, Weber, & Simon, 1992).
Clinical Implications Open wounds, edema, and scar should be evaluated and recorded on a regular basis. Photographs should be taken when possible. The age of the child does not change the evaluation procedure. However, in some cases the evaluation process is challenging.
PAIN
Figure 17-10 Functional dexterity test. (From Aaron DH, Stegink Jansen CW [2003]. Development of the functional dexterity test [FDT]: Construction, validity, reliability, and normative data. Journal of Hand Therapy, 16[1]:12–21.)
Determining the level of a child’s pain is difficult at best. Often, if the child hurts or perceives that something may hurt, a protective posture is assumed and the child refuses to let anyone touch the hand. The therapist must first differentiate between fear and true pain. With newborns and toddlers, the initial approach is to encourage the child to move the hand and perhaps grasp a colorful object. Distraction is the best tactic for this age group. The therapist’s observation skills are the most valuable evaluation tools. A similar approach is
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helpful with children and adolescents. However, these children may be able to provide more information with use of such pain evaluation tools as the following: 1. Body Charts. The child points on a picture to where it hurts; the therapist offers descriptive words to help the child explain the nature of the pain (Maurer & Jezek, 1992). 2. Visual Analog Scale (VAS). This is a vertical or horizontal line of 10 cm with one end labeled “no pain” and the other “terrible pain.” The therapist asks the child the mark on the line the place that best describes the amount of pain. A drawing of a happy face on one end and a sad face on the other also may be used. 3. Numeric Rating Scale (NRS). The child is asked to pick a number between 0 (no pain) and 100 (lots of pain). Although there is high correlation between the VAS and the NRS, children may remember the number they assigned to their pain and thus may reduce the validity of monitoring improvement over time (e.g., the child might tend to keep picking the number chosen previously rather than judge pain objectively at that moment) (Maurer & Jezek, 1992). 4. Verbal Rating Scale (VRS). The child is asked to pick from simple descriptive words that he or she can identify with to describe the pain. Examples are “lots of pain,” “some pain,” or “no pain” (Maurer & Jezek, 1992). 5. Face Pain Scale-Revised (FPS-R). This is a pain measurement scale that uses pictures representing facial expressions to determine intensity. It is used for children ages 4 to 16 (Hicks et al., 2001).
HAND SENSIBILITY Normal hand function requires normal sensibility, as well as mobility and strength. Sensibility should be screened in all children who can reliably communicate information about the sensitivity of the hand. On the initial screening, the therapist asks if the affected hand feels the same as the unaffected hand. The therapist then asks the child to report if there are differences in feelings between the two hands as the therapist strokes both hands. With vision occluded, the therapist touches a finger and has the child tell what finger was touched. The therapist moves the affected finger and asks the child to mimic the movement with the other hand. There are many creative ways to determine if the nerves of the hand are viable. When this is not possible, information must be gained through observing the child use the hand and noting sympathetic functions such as skin color and texture, temperature, sweating, nail changes, or hair growth. This helps the therapist determine if there is a nerve problem. Stereognosis and graphesthesia are other forms of sensory screening in early child-
hood. The therapist asks the child to identify familiar objects or symbols held in the hand or drawn on the palm of the hand while the eyes are closed. Children ages 6 and older should be able to undergo a complete sensory evaluation if indicated by the initial screen. Information on specific testing procedures is available in the literature (Callahan, 2002). Sensory testing can be divided into: Threshold Tests: Tests that determine the minimum stimulus perceived (e.g., pain, temperature, pressure), such as the vibrometer and the Semmes-Weinstein pressure aesthesiometer or pin prick. Functional Tests: Tests that assess the usefulness of the sensation, such as moving and static two-point discrimination, touch localization, and the Moberg Pick-Up Test (Callahan, 2002).
ACTIVITIES OF DAILY LIVING The therapist must know normal expected levels of independent function for each stage of development. This knowledge is necessary to set treatment goals. The therapist may have to develop realistic expectations of “normal” for the child with congenital differences. Expected levels of function are compared with what the child is doing at the time of the evaluation. The stage of healing needs to be taken into account, because some children are temporarily immobilized in the early stages of healing. For many this does not affect their long-term function, whereas others may have permanent impairment and must learn new adaptation skills. Goals are set based on expected outcomes. A baseline ADL evaluation should be administered for each child. Table 17-1 is an example of a functional hand evaluation tool.
Clinical Implication A thorough evaluation has a different meaning for each diagnosis and age group. Many assessment tools are available. Therapists must choose carefully and assure that each evaluation looks at all components of function appropriate for the specific child, diagnosis, and context. Evaluation is the road map for treatment and progress.
TREATMENT OF TRAUMATIC HAND INJURIES IN CHILDREN Treatment of the pediatric population incorporates a “playful” dimension. Couch, Deitz, and Kanny (1998) reported on the role of play in preschool population. They concluded that therapists must increase the emphasis on play when evaluating or treating children.
Pediatric Hand Therapy • 377
Table 17-1
Hand therapy screening evaluation
FUNCTIONAL HAND EVALUATION NAME___________________________ DOMINANCE_____ INVOLVED SIDE______ AGE____ DATE_______ HAND/WRIST EVALUATION Strength
R
L
Wrist/Hand Special Tests
Right
Grip
Intrinsic tightness (where?)
+
Key pinch
Tight web spaces (where?)
−
Left +
−
Pencil pinch Fingertip
Index/middle Ring/small
Spontaneous use of hand Bilateral versus unilateral use
Dexterity
Special hand posture Describe
Functional Dexterity Test 19,20
Volitional release
Comment
Sustained grasp Functional reach to
Prehension Patterns (Percent of normal)
Mouth Back of neck
Fingertip pinch
Small of back
Key pinch
Hip
Pencil pinch (three jaw chuck)
Other shoulder
Ball grasp
Head
Cylindrical grasp
Feet
Suitcase grasp
Other
Other Continued
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Table 17-1
Hand therapy screening evaluation—cont’d
Girth (cm) Wrist
Manual muscle testing (0–5)
Palm (Proximal crease)
Specify ms tested
Proximal phalanx Middle phalanx Distal phalanx Volumeter
Special descriptors of hand function
Other ADL: Dependent/mod assist/ minimal assist/independent List
Sensation
Index Middle Ring Small Thumb Palm Tinels Other Comments
Order of Return 1. 2. 3. 4. 5. 6. 7. 8. 9. 10.
30 CPS Heavy moving touch Heavy touch Temperature Position sense Light moving touch Light touch 256 CPS Moving 2-point Static 2-point
A = Active P = Passive F = Functional B = Blocked
1. Pain (1 Norm to 10 Painful)
2. Hypersensitivity (1 Norm to 10 Sensitive)
Pediatric Hand Therapy • 379
Table 17-1
Hand therapy screening evaluation–cont’d
Range of Motion
R
L
WRIST Palmar flexion Dorsiflexion Radial deviation Ulnar deviation Other
THUMB Flexion MP Extension MP Flexion IP Extension IP Hyperextension IP Palmar abduction Radial extension (reposition) Mid-position Opposition (imp. rate) Thumb to base 5th digit Other description
Index Finger
R
L
Ring Finger
Flexion MP Extension MP Deviation/rotation Flexion PIP Extension PIP Flexion DIP
Flexion MP Extension MP Deviation/rotation Flexion PIP Extension PIP Flexion DIP
Extension DIP Other description: Long Finger
Extension DIP Other description: Small Finger
Flexion MP Extension MP Deviation/rotation Flexion PIP Extension PIP Flexion DIP Extension DIP Other description:
Flexion MP Extension MP Deviation/rotation Flexion PIP Extension PIP Flexion DIP Extension DIP Other description:
R
L
Opposition Thumb to Fingertip (cm) Index finger Long finger Ring finger Small finger
Fingertip to Palmar Crease (cm) Index finger Long finger Ring finger Small Finger
Fingertip to Palmar Digital Crease (cm) Index finger Long finger Ring finger Small finger Other description:
Goals (Parent/patient generated and rated 1 to 10 from least to most important): 1. 2. 3. Therapist Signature: ________________________________ Date:_________________________________
R
L
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In hand therapy, creative play helps the child participate in his or her own therapy. Activities such as playing tictac-toe in putty to increase pinch strength or playing dice games or jacks to enhance and encourage prehension and dexterity engage the child while minimizing the difficulty of using the injured hand. The therapist provides a safe environment, encourages active participation, and offers age-appropriate activities. The therapist must “get on the floor” to engage the child in fun yet purposeful activity and seek to gain the child’s permission to be touched. Through engagement in play, the child is involved to the fullest extent in making choices in the rehabilitation program. The parents or guardians should be educated about how to use therapeutic play with the child. Treatment varies based on the diagnosis. Children are not small adults. They are more susceptible to injury because they have a high power-toweight ratio and the neurologic mechanism necessary for motor control is not yet fully developed. Children do not assess risks in the same manner as adults. More than half of the fractures seen in children are in the upper limb (Graham & Hastings, 2000). It is rare to see a young child with fractures. Often, these fractures may be attributed to child abuse. The growing skeleton differs from the mature skeleton. In the growing skeleton some fractures are managed with less difficulty and for a shorter length of time. Conversely, fractures that involve growth plates may lead to long-term morbidity if treated incorrectly. Mahabir and co-workers (2001) noted that the incidence of hand fractures in children rose sharply after the age of 9 and peaked at age 12. Sports activities were the most common cause of fracture for both boys and girls. The fifth metacarpal was the most commonly fractured bone (21.1% of the total sample of 242 fractures in their study), 60.2% were nonepiphyseal fractures and 39.8% were epiphyseal fractures. Of these, most (90.4%) were Salter-Harris type II (the fracture goes through the physis and exits the metaphysic of the bone). They reported that most fractures heal within 2 to 3 weeks with excellent functional outcomes (Mahabir et al., 2001). In another study, Zimmermann and co-workers (2004) followed 220 children with distal forearm fractures for 10 years. They concluded that the younger the child at the time of injury, the more favorable the results. Children who were 10 years old or older at the time of a severe fracture had the poorest results.
bones continue developing until maturation of the pisiform, which occurs around the age of 9. The flexibility that children enjoy, as well as the larger amount of cartilage in their wrist, helps decrease the number of injuries to the wrist compared with adults. The most common wrist fracture is of the scaphoid, usually seen in children older than 7 years of age (Beatty et al., 1990). Participation in sports has increased the incidence of wrist fractures. The immature skeleton makes radiographic information difficult to read, and thus diagnosis is challenging. Often children are sent to therapy with a general diagnosis of “wrist pain.” The child can be referred after a period of plaster immobilization, or immediately after injury, generally for splinting. When a scaphoid fracture is found, it may not be clear if a child has a fracture at the time of the initial visit to the doctor. Typically, the child is placed in a long arm spica cast for approximately 2 weeks (assuming a scaphoid fracture). X-rays are repeated at that time. If no fractures are determined to be present the child starts therapy. If a fracture is present, casting continues until the fracture begins healing. This may be 6 weeks or more. The doctor determines when the child can start therapy (Graham & Hastings, 2000) (Figure 17-11). Once the child is referred to therapy, the focus is on protecting the wrist through splinting. Therapists must assure that ROM of the affected and nonaffected joints are maintained and that pain and edema are controlled. The ultimate goal is to return the child to normal activity.
Evaluation Types of assessments performed are dictated by the age and cooperation of the child, as well as the attitude and willingness of the parents or guardians. A com-
WRIST PAIN AND WRIST FRACTURES At birth, the ossification of the carpus has not yet begun. Through the first years, with the appearance of the capitate at approximately 6 months, the carpus
Figure 17-11 Full arm cast.
Pediatric Hand Therapy • 381 plete evaluation includes most of the following components: 1. Observation from a distance to note if the child uses or protects the hand. This provides information about the level of pain or discomfort and use patterns and information on the interaction with the parents or guardians. 2. Interview with parents or guardians for information on the child’s hand use patterns under normal conditions, including handedness, participation in sport activities, hobbies, and medical history. 3. Determination of pain level and positions of function and comfort. 4. Determination of the presence of edema. 5. Determination of sensory involvement (e.g., displaced Salter-Harris Type II fractures of the distal radius epiphysis may affect the median nerve) (Binfield, Sott-Miknas, & Good, 1998). 6. Determination of degrees of pain-free ROM (e.g., shoulder, elbow, forearm, wrist, digits). 7. Determination of dexterity and age-appropriate manipulation skills. 8. Determination of ADL independence. 9. If the child is in Phase III (see the following) of the healing process, muscle strength may be assessed. 10. Additional interview with child and parents or guardians to determine their goals.
Figure 17-13
Cock-up splint.
Fabricate Splint to Protect Wrist 1. Protect the wrist for comfort if there is no fracture. Use a simple volar wrist cock-up with the wrist in neutral to 20 degrees extension (Figures 17-12 and 17-13). A dorsal component can be added for extra
stability and control. The young child with a short lever arm requires a splint that goes above the elbow to keep the splint in place (Figure 17-14). 2. If a scaphoid fracture is present or suspected, the splint design includes the thumb (Figure 17-15). The IP of the thumb can be free. For comfort the splint is applied on the volar surface with dorsal support. The considerations listed in the preceding apply as well. a. Young or unreliable children need a splint that includes the elbow to secure the splint and keep it from coming off during play. b. The splint is worn at night and during the day when the child is in school or otherwise out of the immediate presence of a watchful adult. It should be removed for supervised exercises and light ADLs.
Figure 17-12 Cock-up splint. (Courtesy of Kimberly Goldie Staines.)
Figure 17-14
Treatment
Above-elbow splint.
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Figure 17-15 Thumb spica splint. (Courtesy of Kimberly Goldie Staines.)
c. Splint wearing time is decreased as wrist pain decreases and strength and ROM increase, usually 3 to 6 weeks after injury. Often at this stage the hard splint is changed to a soft splint made by taping or neoprene if pain persists (Figures 17-16 and 17-17). Edema Control (Phase I) If edema is present, the child is given a pressure garment such as an elastic glove or wrap. The child and parents or guardians are instructed in positioning the limb in elevation, gentle motion, and retrograde massage. All activities should be at heart level or above (the hand held higher than the elbow and at or above the heart). If the swelling is severe, a “sandwich splint” may be necessary initially (see Figure 17-30 later in this chapter).
Figure 17-16
Taping of wrist to limit motion.
Figure 17-17
Neoprene wrist and thumb splint.
Exercise Activity (Phase II): 3 to 6 weeks after Injury The child is encouraged to begin short arc ROM exercises within his or her pain tolerance. This should take the form of play. Initially, while the wrist is still healing, no resistance is applied. The child is allowed to “get to know the hand again.” Play can be with bubbles or water (cool and elevated if swelling is present). Other effective activities are games that require grasp-release and reaching of light objects (e.g., work on vertical surfaces, use stickers, felt boards, magnets). Gentle exercises and activities are done through Phase II of healing. Bilateral dexterity activities, such as threading beads, may encourage use of an injured and painful hand. Strengthening (Phase III) The child begins strengthening the hand and wrist as pain subsides and the fracture heals. There should be “no pain with loading” such as when making a fist or pushing off from floor or chair before beginning a strengthening program. Strengthening is incorporated into the child’s daily activities and play. Throwing balls to encourage bilateral use or playing with putty is effective for a strengthening program (Figure 17-18). Education Educating the parents or guardians on all precautions about the child’s injury and what to expect with the healing process is part of the treatment program. The therapist assures that both parents or guardians and child demonstrate understanding of the home program, splint wear, and activities that can be harmful. The home program includes pictures and written instructions. The number of clinic visits varies with the child and degree of impairment. However, many children can be treated effectively with a comprehensive
Pediatric Hand Therapy • 383
3.
4. 5.
6.
7. Figure 17-18
Use of putty for strengthening.
home program and only occasional visits to the therapist for evaluation and update of home exercises.
parents or guardians. Take a full history; include activities, hobbies, and medical history. Determine pain level. Determine the position of function and comfort. What is the position of the affected digit? Is there any deviation, angulation, or rotation? Where? Is the digit stable? What position exacerbates symptoms? (Shuaib, 1997). Determine the presence of edema. Determine the amount of pain-free ROM of the digits and proximal and distal joints. Check ROM of the entire extremity. Check dexterity; determine appropriate manipulation skills for the age of the child. Is he or she using the affected digit? Strength may be tested in Phase III of healing. Usually grip strength that distributes the force across all digits is easier to tolerate than pinch strength with the affected digit. Strength information also may be obtained by observing usage of the hand. Is the child performing ADLs in the normal and customary fashion? What are the child’s and parents’ goals?
FRACTURES AND DISLOCATIONS OF THE DIGITS
8.
The incidence of hand fractures rises dramatically after the age of 8, with boys presenting more often than girls with both fractures and dislocations. Phalangeal fractures slightly outnumber metacarpal fractures. Metacarpophalangeal joint dislocations are among the most common of childhood injuries. Physeal injuries may amount to 33% of the fractures seen. These fractures are classified using the Salter-Harris classification, with Salter-Harris II being the most common (Graham & Hastings, 2000). Most of these children are treated conservatively and followed by the physician. Children who are referred for therapy are the ones with complications such as persistent pain, decreased ROM, or refusal to use the hand. When a child comes to therapy, an accurate description of the injury, how it happened, treatment provided by the physician, and length of immobilization should be available to the therapist.
The treatment is based on what is seen clinically at the time of referral, because these children may be sent to therapy at different points after injury. What stage of healing is the injury? What were the results of the evaluation?
Evaluation 1. Observe the child from afar. Watch him or her use the hand. The way the child uses the hand provides information on pain and usage patterns. Is he or she protecting it or using it? Is the child using the affected digit when using the hand? If the thumb is involved, is there a grasp and release pattern? Is there sustained grasp? 2. Determine the child’s demands on the hand under normal conditions. Does he or she play sports or participate in arts and crafts? Which is the dominant hand? Interview the child (age dependent) and
Treatment
General Splinting Considerations The splinting goal is to keep the fracture stable until healed. 1. Ligament Disruption or Dislocation. The splinting goal is to align the finger and reduce the stress on the affected structures. In certain conditions and with certain age groups a hinged-type splint or one that allows short arc ROM may be appropriate. Use buddy splinting, which is taping the affected finger to the adjacent one for stability at the onset if the disruption is not significant. Otherwise buddy splinting can be used for protection after 3 or 4 weeks of immobilization. 2. Phalanx Fracture or Displacement. These are most common in border digits (Hastings & Simmons, 1984). Splinting usually includes the adjacent digit and, depending on the age of the child, with or without the wrist. Common Digital Injuries and Their Treatment Gamekeeper’s or Skier’s Thumb. This is an ulnar collateral ligament tear or stretch. In the older child this involves splinting the thumb MP with a hinged splint allowing MP flexion-extension motion but restricting radial deviation (thus protecting the ulnar
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collateral ligament from elongation). In the younger child, a hand-based thumb spica splint is suggested. Splint wear depends on healing and at what point the child was referred. Usually the splint is worn for 6 to 8 weeks after injury. If there are no deforming forces and the joint is stable, splinting can be discontinued except for sports or other activities that may necessitate extra protection. When the splint is removed, the child and parents or guardians are instructed in ROM exercises and protection of the hand during sports or play. Use of tape and neoprene for added protection of the hand during activities or sports is advised. Proximal Interphalangeal (PIP) Joint Dorsal Dislocation. This injury, although generally rare in young children, is the most common PIP dislocation in adolescent athletes. It usually is called “jammed finger.” Many of these are reduced on the playing field. They may have associated volar plate and collateral ligament injuries. Splinting for this condition may take the form of buddy taping if the injury is mild, or complete rest with the PIP joint in approximately 20 to 30 degrees of flexion (to protect the volar plate). After a couple of weeks of complete rest, if instability is noted, then a dorsal blocking splint (a splint that allows PIP flexion but blocks extension at −30 degrees) can be fabricated. This type of splint allows the volar plate, which is injured, to heal with no tension, while still allowing short arc ROM. This can be in the form of a hinged splint or a splint with “horse blinders” that serve to guide the motion. In some cases, protected early motion in these splints is started immediately. If the PIP is swollen, then edema control measures such as pressure wrap and elevation may be necessary. When the protective period is over, home exercise emphasizing composite flexion, as well as protected PIP extension, is taught. The child and parents or guardians should be instructed in all precautions. Mallet Finger. This is a physeal fracture of the distal phalanx, with or without displacement. The fracture may be displaced by the pull of the extensor tendon insertion. Most of these fractures are treated closed (e.g., do not need surgical intervention) (Graham & Hastings, 2000). The finger should be splinted with a dorsal splint over the DIP joint. There should be no hyperextension of the DIP joint in the splint, so as not to blanche any of the dorsal skin and thus compromise circulation (Figs. 17-19 and 17-20).Tape should be used to secure the splint at the proximal edge going around the finger. A longitudinal strip of tape coming from the volar to dorsal aspect of the finger should secure the distal phalanx into the splint. A last piece of tape is used horizontally around the finger’s distal phalanx. This splint allows good sensory input on the
Figure 17-19
Mallet splint: lateral dorsal view.
Figure 17-20
Mallet splint: volar view.
volar surface of the affected digit. The hand can be used in normal ADLs with the splint. The splint should be kept dry and changed every couple of days; check the dorsal skin for breakdown. The tip of the finger should be held in extension during the splint changes. For young or unreliable children, the PIP joint or PIP and MP joints should be included to secure the splint. Watch for skin breakdown under the tape, especially with young children. The splint should be removed after 6 weeks. If there is full extension, gentle short arc of active ROM can begin, with night and PRN (whenever necessary) day splinting. If the DIP joint is not extending actively, continue with continuous splinting for two more weeks. After removal of the splint, watch for an extensor lag, which is the inability to extend the DIP into full extension because of poor pull-through of the terminal extensor tendon. This may last for up to 4 to 6 months. This may result from elongation of the tendon, which must stay in a shortened position to heal and function properly. Provide the child and parents or guardians with home instructions and precautions.
Pediatric Hand Therapy • 385
TENDON I NJURIES
Flexor Tendons
Broken glass is a common cause of tendon injuries in the young. Older children also can suffer tendon injuries secondary to broken glass and sharp metal, as well as through participation in sports and other activities. Often the cut is tidy, especially with broken glass. The management of these injuries depends on the age, understanding, and cooperation of the child (Favetto et al., 2000). Tendon healing has been a source of wonder and research for many years. Clinicians must balance the need of the tendon to heal with its need to glide. Alternately, we know that if a tendon is immobilized it will heal, but it will also adhere to the surrounding tissue, and thus not glide. We know that if the tendon is mobilized too fast or too hard, it will rupture. The challenge in tendon management is to find a compromise between protecting the blood supply and nutrition to the healing tendon, while allowing gliding so that the tendon will not adhere to the surrounding tissue. The goal for tendon rehabilitation is to protect the tendon through Phases I and II of healing (see the following), while allowing some protection, below breaking strength motion. This is particularly important for flexor tendons, yet difficult to do with young children. It is believed that children heal faster and with fewer adhesions than adults (al-Quattan et al., 1993). This information allows some creativity and deviation from the adult tendon protocol in how to manage these injuries postoperatively. Conventional treatment protocols for adults have been the traditional controlled protected motion for both flexors and extensor injuries, and more recently gentle protected active motion for flexor tendon injuries. Rarely is an adult treated with complete immobilization after flexor tendon injury; however, that might be the treatment of choice for extensor tendons. With children, it is common practice to immobilize the hand for tendon injuries. With children under the age of 9, the elbow is included with a long arm cast or splint. In an interesting study, Friedrich and Baumel (2003) reported good success using the modified Kleinert surgical repair technique with early protected motion (see next section) for children ages 9 months to 18 years who suffered flexor tendon injuries. Their treatment technique varied from the traditional, which supports the idea that creativity and individuality of protocol per patient are advisable and possible (Friedrich & Baumel, 2003). Tendon injuries are classified by zone of injury. There are some variations in treatment protocol based on the zone of injury, specifically for extensor tendons. With flexors, however, many children are treated in the same manner regardless of the zone.
Immediately Postoperative (Phase I) There are several accepted protocols for flexor tendon repair. All tend to require 3 to 4 weeks of splinting, with or without motion. The decision about which protocol to follow is dictated by the surgeon’s choice of suture style, as well as the age of the child and the overall condition of the tendons and hand. Young and unreliable children usually are placed in a long arm splint or cast, placing the elbow in flexion (60 to 70 degrees), forearm in neutral, wrist in neutral or with slight flexion (0 to 20 degrees), metacarpal joints in flexion (60 to 70 degrees), and interphalangeal joints in extension. This splint can be made intraoperatively and then changed or adjusted in therapy on the second or third day postoperatively. The patient is followed in the clinic for splint checks and adjustments one to two times weekly for 3 to 4 weeks. The parents or guardians should be instructed in all precautions about the child’s injury. They must understand the importance of observing the fingers for good color, thus assuring good circulation. They must be instructed in edema prevention through elevation. They also must understand the importance of encouraging the child to move the uninvolved joints such as those not splinted. The splint may be removed to clean the wounds or stitches. Great care must be taken not to move the wrist and digits during dressing changes, particularly if done by the parents or guardians. Some elbow motion can be performed carefully when out of the splint. Clinical visits include dressing changes and gentle passive motion, of the elbow, wrist, and fingers, in a protective manner by the therapist to protect repair at all times (Penttengill & van Strien, 2002). All reliable and older children may be treated like adults and follow the early protective protocol of Kleinert or Duran-Houser or the active motion protocols that are widely described in the literature (Penttengill & van Strien, 2002). The splint is fabricated and worn consistently for 4 weeks. In most cases, the child is splinted in a dorsal blocking splint, with the wrist placed in neutral to 20 degrees of flexion, and metacarpals placed in 60 to 70 degrees of flexion by the dorsal hood. The fingers are placed in extension in the hood for the early active motion protocols and in rubber band traction for the protective motion protocols. For the protective motion protocol, a dorsal splint is fabricated, placing the wrist in neutral and MPs in 70 degrees of flexion with rubber band traction on the affected fingers or all fingers, depending on the surgeon’s preference and reliability of the child. The rubber bands pull the fingers into the palm, creating a fistlike appearance of the hand in the splint. The child
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is shown how to release the tension on the rubber bands so that he or she can achieve maximum extension (full interphalangeal extension) into the dorsal hood, allowing flexion through the pull of the rubber bands. At night the fingers are released from the rubber bands and secured in extension to the dorsal hood with a wide strap. This, along with the protective daily motion, is aimed at allowing some gliding of the flexor tendons, as well as preventing PIP flexion contractures. If the IPs of the fingers are not able to extend completely (especially at the PIP joint level), a wedge is placed on the dorsal aspect of the proximal phalanx (P1) to encourage PIP extension. This can be accomplished with the use of a pencil or piece of foam (Figs. 17-21 to 17-23). Some children may be placed in the dorsal hood as described above, with no rubber band traction. These children follow the Duaran Houser protocol of protected passive ROM (Penttingell & van Strien, 2002). Those following an early active motion protocol go through a closely monitored program of tenodesis exercises; specifically, wrist flexion with finger extension followed by wrist extension with finger flexion. Also, the therapist may place the digits into flexion and instruct the child to “hold” them there with an isometric contraction. These children should be followed closely when they perform place and hold or tenodesis exercises (Figs. 17-24 and 17-25). The child should be followed in therapy no fewer than two times a week for the protective motion protocol, in which the therapist checks the splint and the wounds or stitches, as well as performing passive ROM when indicated, especially to DIP and PIP joints. Nonaffected joints should be exercised on a regular basis. If an early active motion protocol is followed, the child should be followed daily in therapy.
Figure 17-21
Kleinert splint in extension.
Figure 17-22
Kleinert splint in flexion.
Figure 17-23
Kleinert splint in night position.
Figure 17-24
Early motion splint, place, and hold.
Pediatric Hand Therapy • 387 activities. The design transfers the work load to the long flexors and thus promotes gliding (Figure 17-26). Resistive extension may be initiated and exercises such as putty rolling can be introduced. Encourage the child to use the hand in most of the ADLs, being careful not to perform activities that require great volitional strength. The child should engage in dexterity activities that encourage differential gliding of the FDS against the FDP. Edema and scar management are addressed as necessary. Splinting at this point is used based on clinical goals such as proprioception to encourage pull-through or positional to prevent or address deformities.
Figure 17-25
Early motion splint at rest.
Scar and edema management through pressure and elevation is initiated for all patients. Pressure with silicone gel or other sterile material can begin while stitches are still in place. Four Weeks Postoperative for All Protocols (Phase II) An initial evaluation is performed. Gentle active exercises are initiated into flexion, with focus on full extension in a protected manner (i.e., full IP joint extension with MP joints in flexion; full wrist extension with digits flexed). The splint is worn protectively during the day and at night. Precautions against full composite extension (extending wrist and digits together in the same movement) or resistive flexion are explained carefully. No blocked exercises are allowed. Dexterity activities and gentle ADLs are shown. The scar is managed through pressure and stretch and by fabricating the protective splint on the volar rather than the dorsal side for added pressure to the scar. The wrist is placed in slight extension in the splint. Six Weeks Postoperative (Phase III) Reevaluate status, including gross grip (pinch strength evaluation usually is deffered until 8 weeks, when the tendon is strong enough to withstand the strain). Exercise can be upgraded to tendon gliding exercises (allowing the flexor digitorum profundus [FDP] to glide against the flexor digitorum superficialis [FDS]) and gentle blocking. When instructing in blocked exercise (only advised if gliding is moderate to poor) tell the child to only use 30% to 50% of his or her strength. Blocked exercises are a common reason for tendon rupture. If pull-through is poor, a blocking glove can be fabricated, blocking the MPs at 0 to 20 degrees of flexion and allowing full ROM of the IPs. This glove is worn when the child is using the hand in normal
Discussion The literature suggests many different approaches to treating tendon injuries in children and adults. Kayli and co-workers (2003) evaluated results of early mobilization of flexor tendon injuries in children ages 2 to 14, using above-elbow stabilization with a Duran-type protocol. They reported favorable results with a mean total active motion (0% to 100%) of 78.5%. They did note that the age of the child and the presence of digital nerve involvement affected the results (Kayli et al., 2003). Fasching and co-workers (1998) looked at 90 severed digits in 38 children with the mean age of 4, over a 4-year period. Children were all treated with the Kleinert protocol. They had five cases of tenolysis and one rupture. In the remainder of the cases they had 88% good results and 2% poor results, which they assessed based on Buck-Gramcko’s classification. They concluded that excellent results can be achieved with experienced therapists and informed parents. Grobbelaar and Hudson (1994) reported 82% excellent results based on Lister’s criteria in their sample of 38 children (average age 6.7 years). They had no tenolysis and
Figure 17-26 Blocking glove. (Courtesy of Kimberly Goldie Staines.)
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three ruptures. They suggested better results when both the FDP and FDS are repaired. Friedrich and Baumel followed 173 cases of flexor tendon injuries, ages 9 months to 18 years, over a 10year period. They concluded that early motion should be initiated at any age, because of problems they saw with immobilization, even in the young. Their protocol follows a modified Kleinert routine, with a cast placed in surgery either above the elbow or not, and the wrist placed in 5 to 10 degrees of flexion and extended to the MP joints. Digits are flexed by rubber band traction that is routed through the palm. The initial goal is to get full IP extension beginning on the first postoperative day, with five to six exercises per day by the third day. The goal is to achieve full flexion by 3 months. Based on the Buck-Gramcko scale, they reported 95% good results, with four cases of poor results (Friedrich & Baumel, 2003) (Figure 17-27). Ebinger and co-workers (2003) looked at two groups of children with flexor tendon injuries. In group A (children under 6 years of age), the postoperative treatment consisted of immobilization for 3 weeks. In group B (older children), early passive mobilization was employed. Follow-up showed that the mobilization
Figure 17-27 Friedrich and Baumel casting for early motion. (From Friedrich H, Baumel D [2003]. The treatment of flexor tendon injuries in children. Handchir mikorchir plastic chir, 35(6):347–352.)
group had good results compared with only average in the immobilized group at 3 months postoperatively; however, at 3.7 years postoperatively, both groups showed good results.36 Clinical Implications Flexor tendon protocols vary from immobilization to protected motion to active motion. Long-term results of studies do not show significant difference in the early motion protocols; with the young, no study has shown conclusively that early motion is preferred over immobilization.
Extensor Tendons Zones I and II injury distal to the PIP (known as “mallet finger deformity”) is discussed in the fracture section of this chapter. Treatment for a tendon avulsion from the distal phalanx is the same as the treatment described for mallet finger deformity. The literature shows little or no difference in treating extensor tendons with early protected motion rather than immobilization. Immobilization is the treatment of choice in treating children of any age who suffer an extensor tendon injury. Immediately Postoperative Zones III to VII (Phase I) Splint the child with an extensor tendon injury in a protective splint that has both a dorsal and volar component for better security and stability of the splint. For Zone III injuries at the PIP level, a hand-based splint, with the MPs at 20 to 40 degrees of flexion and the IPs extended, is commonly used. The splint can go above the wrist if it is feared that the child will not keep the splint on. The splint should go above the elbow for the young and unreliable child, with the elbow kept at 60 to 70 degrees of flexion; however, that is rare. For all other zones, the forearm is neutral or pronated, the wrist is in 30 to 45 degrees of extension, the MP joints are kept at 30 to 60 degrees of flexion (depending on the zone of injury), and the IPs are extended (including the elbow if necessary to maintain the splint on the child). The exact position depends on the stress on the repair that can be determined intraoperatively and communicated to the therapist. The child should be followed in therapy at least two times a week during the 3- to 4-week immobilization phase. At each visit, the wound or stitches should be cleaned, the dressing changed, gentle ROM should be performed with all uninvolved joints, and protected ROM may be performed with the involved joints (patterns in extension only). Precautions should be explained to the child, as well as the parents or guardians about keeping the arm dry and clean, elevating the extremity, and watching the color. The parents should
Pediatric Hand Therapy • 389 notify the doctor immediately if any discomfort or unusual swelling is seen. Scarring and swelling are addressed through pressure under the splint and elevation. Three to Four Weeks Postoperative Zones III to VII (Phase II) A baseline evaluation is done at this time. Edema is measured, any scars are noted and described, and gentle active ROM and dexterity are recorded. If there is sensory involvement, a baseline sensory evaluation should be performed. Particular attention is paid to any adhesions along the tendon or to a lag. If a lag exists, continued splinting for an additional 1 to 2 weeks may be advised (Figure 17-28). Patients may begin active range of motion (AROM) at this time; the exercises should be carefully monitored for the first couple of weeks so as not to strain the repair. Movements should be in a tenodesis fashion; wrist extension with finger flexion, wrist flexion with finger extension. The splint may be adjusted or kept the same. It is used between exercise sessions for protection and at night. The child may use the hand for light ADLs and for bathing. Precautions against resistive extension or composite flexion (fisting with wrist flexion putting maximal strain on the extensor mechanism) should be carefully reviewed with the child and parents or guardians. If the child can follow directions and has participating parents or guardians, and barring complications, he or she can perform much of the therapy on a home program basis and be followed in therapy once weekly. The home program consists of exercises, and edema and scar management. Home education about precautions and functional use of the hand also is pro-
vided. If a child is not progressing, then more frequent visits to the therapist should be initiated. Six Weeks to Eight Weeks Postoperative Zones III to VII (Phase III) The child may now use the hand in most of the ADLs. Precautions against composite flexion until 8 weeks postoperatively continue. Exercises that encourage active extension, such as dowel or putty rolling, should be used (Figure 17-29). Edema is a minimal problem by this stage. The scar still needs attention. Splinting is used for protection if a lag is present; otherwise it is used as needed depending on the clinical manifestation. Complete evaluation should be performed, looking at all aspects of hand function. Discussion Little is available in the literature about extensor tendon management in the child. Most of the data are based on adult populations. Protocols that are available for adults certainly can be used for the older and reliable child. Evans (2002) suggested protocols for each zone of injury, which may be appropriate to use under certain circumstances with the pediatric population. Clinical Implications Extensor tendon injuries in children can be treated with 3 to 4 weeks of immobilization followed by a program of gradual increase of motion and use. In treatment, all efforts must be made to avoid an extension lag, including increasing immobilization time if needed.
THERMAL HAND I NJURIES IN C HILDREN Burns in the upper extremity often occur in children. Patterns of burn injuries in children differ from adults because of children’s development, their physical and psychological aspects, as well as how children get burned. Clarke and co-workers (1990) claim that children are different than adults in that burns caused by scalding
Figure 17-28
Extension lag.
Figure 17-29
Rolling exercises to promote extension.
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are the most common, and children develop less stiffness than adults when immobilized. Children are curious and thus put themselves at risk. Common causes for hand burns are hot cups of coffee, hot water, irons, and heaters. The mechanism of injury and the nature of the burn agent dictate the severity of the burn. Sunburn can produce a superficial burn, whereas hot water produces a scalding injury that can be superficial or deep. A flame may result in full thickness burns (de Chaliain & Clarke, 2000; Greenhigh, 2000). Burns occur initially when there is direct contact with a thermal agent, causing injury to the cellular elements and structural proteins. Subsequently, there is delayed damage secondary to progressive dermal ischemia. When a child is exposed to heat, both the temperature and the time exposed to the heat determine the extent of tissue damage (de Chaliain and Clarke, 2000). Palmar burns in toddlers are increasingly more common. Dunst and co-workers (2004) reported an alarming increase in palmar burns associated with gas fireplaces. Burns have been classified in four degrees, although commonly only three degrees are referred to, as seen in Table 17-2. Rehabilitation of the burned hand should begin immediately after the child has been medically stabilized because a 7- to 10-day delay may result in irreversible functional losses. The general goals of therapy are to prevent deformity and maximize function (de Chaliain & Clarke, 2000). Intervention depends on the phase of healing.
Table 17-2
Phase I: Open Wound The objective for treating a child in Phase I with an open wound includes reducing edema, maintaining digital circulation, limiting inflammation, and positioning and mobilizing the hand early. These are key parameters to aid in the best chance for regaining function (Clarke et al., 1990; McCauley, 2000). Initial treatment of a hand burn must consider wound care, the location of the burn, and the potential deforming forces that will affect the healing. Wound Care Evaluation should consist of a description of the wound, including the wound’s color, size, and depth, as well as any exposed structures. Circumferential measurements with a sterile measuring tape should be taken for recording of edema. All blisters should be noted and marked on a drawing of the hand. When possible a picture should be taken of the wound. Treatment should be coordinated with the burn team and may consist of hydrotherapy (with the appropriate disinfectant agents) or wound cleansing directly with dressing application and changes. Special care should be given to any exposed tendons or bone. The therapist’s role is to guide the team about positioning the hand in the dressing. The goal of positioning is to maintain burned structures on stretch while healing, thus preparing for future functional use. Most commonly a resting splint is fabricated (see the following). Edema and future scarring can be controlled with pressure wrap over the dressing and splint immediately after wounding.
Classification of burn severity
Classification
Depth of Penetration
Clinical Signs
First degree
Superficial—epidermis level
Redness, pain, heals with no scarring (sunburn)
Second degree Superficial Deep
Partial thickness—epidermis and dermis level
Blisters, moist, painful, heals in 2 to 4 weeks, or may go to full thickness, scarring
Third degree
Full thickness
Dermis destroyed, usually needs coverage, white or black, dry, anesthetic
Fourth degree
Full thickness and more
Deep destruction, to bone, needs flaps or grafts to heal
Modified from de Chaliain T, Clarke HM (2000). Thermal and chemical injuries. In A Gupta, SPJ Kay, LRL Scheker, editors: The growing hand, diagnosis and management of the upper extremity in children (pp. 665–692). St Louis, Mosby.
Pediatric Hand Therapy • 391 Positioning The goal of positioning the hand during the healing phase is to maintain maximum potential for function. Often the position of comfort is also the position of potential contracture. Therefore positioning may not always be comfortable, however it is essential for the prevention of contractures. Positioning may be achieved in many ways, the most common is through the use of thermoplastic materials that are custom made for each child. If these materials are not available, plaster, bandages, and other common items may be used. The position that the hand and wrist are placed in are determined by the location of the burns. The placement of each joint in the hand, including the wrist, must be such that the regenerating tissue regains maximum length and pliability. This position may at times be in conflict with the “functional position” of the hand. Positioning decisions need to be made for each child with an exercise regimen that complements the static positioning to maintain function. For example, with palmar burns, the wrist is placed in 20 to 30 degrees of extension, with the MP joints in 30 to 40 degrees of flexion and IP joints in full extension. The thumb should be positioned with maximal web stretching and in midposition between palmar and radial abduction. Care must be taken not to stress the carpometacarpal (CMC) joints. Support to the palmar arch should be provided. The splint should be fabricated on the volar side of the hand so that it puts pressure on the healing wounds. This pressure aids in aligning the collagen and reducing the potential for scarring. However, this pressure must be distributed so as not to cause point pressure areas, which can lead to tissue necrosis. The hand with dorsal burns should be positioned with the wrist in neutral, the MP joints in 70 degrees of flexion, and the IP joints in extension or slight flexion. The thumb should be positioned in palmar abduction with maximum stretch of the dorsal web. The splint should be placed dorsally when possible, thus providing some pressure on the burned tissue. Variations to these positions are done based on the location of the burns. If the web spaces are affected, then the digits should be placed in slight abduction. If both dorsal and volar burns are present, then splinting must consider all areas when deciding on the best position. Each child is different based on the age, burn pattern, and involvement. Children younger than 4 years of age have a small lever arm to stabilize a splint, and thus the splint design perhaps should be above the elbow. The digits perhaps should be positioned in full extension to gain sufficient leverage. In some instances, a “sandwich” splint design may be appropriate; it has the advantage of pressure on all circumferential burns, as well as
preventing the child from removing the splint (Ward et al., 1998) (Figure 17-30). Straps used to secure the splints should be wide and placed diagonally, not circumferentially; when possible, elastic wrap should be used so as not to compromise circulation. Often, no straps are needed, because the splint is incorporated into the total dressing and held in place by bandages or elastic webbing. When using elastic wrap, use no more than three wraps over one area. Make sure even pressure is used. Leave the fingertips open so they can be seen to monitor color. Splints should be worn continuously the first 5 days, removing them for short periods to allow the child to exercise or feed themselves. Thereafter, when edema has subsided and tissue is starting to heal, splint wear time may vary during the day, with continued night splinting used until all scars have matured. Scar and Edema Management Scar and edema management should start immediately after wounding. Pressure and elevation are the appropriate venues in the early phases of healing. Pressure can be achieved through the use of elastic bandages. Elevation can be accomplished through positioning in bed on pillows or with the use of IV poles to “hang” the hand. Attention must be given to the color of the digits when pressure has been applied circumferentially exposing the tips of the fingers, thus allowing visual clues as to the circulatory viability. Children can be advised to “wave” at everyone they see, with their hand held high. When possible, extra pressure can be placed in certain areas, such as the web spaces, with cotton, bandages, or any other available sterile dressings (Figure 17-31).
Figure 17-30 Sandwich splint for edema or scar. (Courtesy of Kimberly Goldie Staines.)
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Part III • Therapeutic Intervention play. Using a whirlpool as a medium for ROM activities and prehension exercises is an option. The therapist must appreciate the patient’s pain level and tolerance and the parents’ anxiety when prescribing exercises or activities. As early as possible, the child must be taught to exercise the entire upper extremity to prevent any secondary stiffness of unaffected joints.
Figure 17-31 Circumference pressure wrapping for burn scar. (From Serghiou M. In McCauley RL (2005): Functional and aesthetic reconstruction of burned patients, CRC Press.)
Exercise and Activities Before initiating an exercise regimen, available active and passive ROM as well as dexterity should be evaluated. This may require sterile instruments and tools. In situations in which goniometric measurements are difficult, the therapist should record functional measures. Although this is not as reliable as goniometric measures specific to each joint, it does give some idea of the child’s ability at that point in time. Ask questions such as: Can the child touch the distal palmar crease when asked to make a fist? Can the child extend the fingers, touch each finger to the thumb in opposition, or bring the thumb down to touch the base of the small finger? Exercise must be tailored to the age and comprehension of the child, as well as the depth of the burns. In superficial burns, active ROM should be started immediately with minimal limitations. For children with deep burns, extreme care must be given to protect structures that might have been affected, such as tendons. If nerves are involved, the hand may be insensate, and extreme attention must be given not to overexercise the part. To allow early motion, but also protect potential weakened structures, the ROM must be done protectively. For example, if the extensor tendons are exposed over the dorsum of the hand, composite fisting must be avoided. ROM should be performed one joint at a time or in a tenodesis manner. As an example, the wrist should be extended when the child is flexing the MCP joints with dorsal burns that expose or affect the extensor tendons. Passive motion may be applied, but with caution, so excess stress is not placed on the tissue the therapist is holding or stretching. Care should be given to maintaining the hand clean and elevated during exercise session. Whenever possible, the hand should be used in a functional pattern because it assists the child in the ADLs and exercise should be incorporated into active
Education The parents or guardians and the child should be provided with information about the diagnosis, expected outcomes, and steps to achieve these outcomes. In this phase, education is primarily related to wound care, dressing changes, positioning, pain management, and limited activity. The parents or guardians are guided through the rehabilitation process and included in all therapy protocols. The importance of maintaining any uncomfortable positions is emphasized. All precautions are explained and reviewed. As indicated, the child is encouraged to use the affected extremity in self-care as much as possible.
Phases II and III: Closed Wound, Immature Scar to Mature Scar In Phases II and III, evaluation is more specific and includes all aspects of hand function. It is performed at regular intervals to record progress and modify treatments. Wound care is discontinued. Scar Management The natural history of a burn scar is for tissue to shorten and contract. The patterns of deformity are well established. In managing the scar, the goal of therapy is to both put pressure on the scar, as well as to direct its orientation. In Phase II, when the scar is immature, care must be taken not to disrupt the healing by “shearing” the scar. Therefore efforts must be made to minimize friction to the healing tissue, yet at the same time apply pressure on it. Pressure can be in the form of customized molds, gel sheets, foam, and other types of materials that provide even pressure to the scar. These pressure molds are secured with elastic wrapping or splinting or both. Decisions are made based on where the scar is and how extensive it is, as well as the age and participation of the child. The function of the hand must not be prevented by the molds during the day. In some situations, there may be a set of pressure molds for night time that differ from the pressure wraps used during the day. In Phase III, massage may be incorporated into the scar management regimen. Creams may be used on a lightly dampened hand to maintain moisture. Massage without cream can be used with pressure to a particular area to mobilize the scar. Also in the late phase a pressure glove may be provided, which can be custom
Pediatric Hand Therapy • 393 made for the child commercially, in the clinic, or at home (Figure 17-32). Care must be taken to apply sufficient pressure to affect the scar, but not so much as to cause vascular complications or restrict function. Pressure wrapping should not exceed 25 to 30 mm Hg to avoid vascular compromise. Pressure should be maintained at all times, except for bathing or changing garments. Pressure garments can be discontinued when the scar has reached maturity; usually when the color changes and the scar is less vascular. The scar may take up to 2 years to mature. Positioning Positioning in Phase II is the same as in Phase I. As the tissue gains intrinsic strength, splinting during the day can become more creative, addressing specific problems. Dynamic splints may be incorporated at this time to encourage pull-through of the tendons, thus improving their excursion or to increase a joint’s ROM. At night, positioning splints should be in place until ROM is normal or any deformity has resolved (Figure 17-33). Exercise and Activities In Phase II the child is allowed to perform active ROM in all planes. The child may now start with composite motion, achieving gentle stretching of the scar while exercising. For example, to achieve stretch or elongation of a dorsal scar, composite flexion with fisting and wrist flexion should be done. Resistive exercises can be performed only if they do not cause friction to the scar. For example, if there is healing dorsal skin, use of putty exercises for grip and pinch strength may be performed, but not if there is a healing palmar scar. Passive ROM is contraindicated in joints that have new healing tissue so as to avoid friction. Dexterity and sensibility should be tested and addressed as necessary. In Phase III, both active and passive ROM as well as strength should be addressed through play and
Figure 17-33 Night position splint for burn hand. (From Serghiou M. In McCauley RL (2005): Functional and aesthetic reconstruction of burned patients, CRC Press.)
exercise. Intrinsic stretching, placing MPs in extension while flexing the IPs, and intrinsic strengthening should be incorporated. Tendon gliding, blocking ROM, and other targeted exercises are employed as indicated. Graded exercise activities should be incorporated that provide ROM, strengthening, dexterity, and psychological stimulation. The activity should be changed often to keep the child engaged. Activities of Daily Living In Phase II, the child should engage in light ADL, but stay away from play or activities that could irritate the scar. Equipment and tool modification should be provided to aid in independent function. This is based on functional limitation and age. In Phase III, there are no precautions—the child should engage in all ADLs he or she can perform, with and without equipment as dictated by the condition. Skin care instruction should be given to the child and parents, as well as education as to sun exposure and other dangers that might damage the healing area.
General Comments
Figure 17-32 Custom ordered burn pressure wrap. (Courtesy of Shrine Burns Hospital, Galveston, TX.)
Treatment of a child with a burned hand must take into account not only physiologic healing, but also psychological and emotional healing. The child’s treatment plan should be formed with the consideration of the child’s family situation, social situation, environment, and available resources. Treatment varies with each developmental stage and the individual response of the child to his or her injury. Play should be incorporated whenever possible. The experience of being burned is frightening and painful to the child. Thus this must be considered in the approach and design of the treatment plan. The literature suggests variation in care at different institutions. Sheridan and co-workers (1999) looked at long-term results of acutely burned hands in 495
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children involving 698 injured hands, over a 10-year period. These authors used ranging and splinting early and throughout the treatment, with prompt sheet autograft wound closure as soon as was practical, and selective use of axial pin fixation and flaps for stability and coverage. They reported normal function in 97% of second-degree burns, 85% of third-degree burns, and 20% normal function in children who had deep structure involvement (e.g., tendon); however, 70% of severely involved children were able to perform ADLs (Sheridan et al., 1999). Barillo and co-workers reported on a rehabilitation protocol for MCP joints in which they used static splinting alternating with continued passive motion (CPM) 4 hours for sedated patients; and CPM alternating with active ROM and night time splinting for MP joints with less than 70 degrees of flexion; and active range and progressive resistance for alert patients with MCP joint flexion of more than 70 degrees. Their patients had an average of 220.6 degrees of motion at discharge and 229.9 at 3 months, with mean grip strength of 60.8 pounds at discharge and 66 pounds at 3 months (Barillo et al., 1997). Roberts and co-workers (1993) reported on seven patients’ hand strength that was followed by ROM, compression therapy, and splinting. They showed that although both grip and pinch strength improved at 6 weeks after injury, strength remained significantly less than normal compared with the norm for age and sex at 6 months. They concluded that although their findings were lower than normal, this did not indicate poor performance in ADLs.
Clinical Implications Children with hand burns should be seen by a therapist early for positioning and gentle motion. Splint design should be dictated by burn location. Children should be followed until the scar has matured, which could take up to two years.
TREATMENT OF CONGENITAL HAND DIFFERENCES There has been a lack of generally accepted nomenclature for the problem in children with congenital differences of the hand. They have been called upper limb or congenital anomalies, malformations, or differences. In this chapter, the word differences is used to describe this population. Further classification of congenital differences has been devised by the International Federation of Societies for Surgery of the Hand (IFSSH) (Swanson, Swanson, & Tada, 1983). This
BOX 17-2
I. II. III. IV. V. VI. VII.
International Federation of Societies for Surgery of the Hand Classification of Congenital Differences
Failure of formation Failure of differentiation of parts Duplication Overgrowth Undergrowth Constriction ring syndrome Generalized abnormalities and syndromes
classification categorized the types of congenital differences (Box 17-2). The treatment of two of the most commonly seen congenital differences, syndactyly and radial club hand, are discussed.
SYNDACTYLY Syndactyly falls under the “failure of differentiation” classification. It is a fusing of adjacent fingers that can be simple (involving only skin) to complex (in which the bones of two digits are fused). Syndactyly is one of the most common hand deformities. It is found in males more than females, and is present in 50% of cases bilaterally. Often syndactyly is associated with other problems, such as polydactyly, clefting, symbrachydactyly, or ring constriction. When these occur, surgery and therapy should take these anomalies into account when planning intervention. The goal of a syndactyly surgical release is to create a functional hand with as few surgical procedures as possible. Intervention can be done as early as 6 months of age or even earlier, especially in border fingers in which length discrepancy is a concern. Full thickness skin graft is almost always necessary for the soft tissue coverage after separation and reconstruction (Smith & Laing, 2000; Dao et al., 2004). Island flap reconstruction in incomplete syndactyly has been advocated by Brennen and Fogarty (2004), in which skin and fat are rotated for coverage, with good results, minimal scarring, and rare need for follow-up skin grafting (Dao et al., 2004).
Postoperative Period: Phases I and II The goal of therapy in the early phases of healing is wound and edema management, followed by prevention of scarring and creep (the distal progression of the commissure), which may occur (Lourie, 1999). The hand is elevated until edema is under control. A dressing may be in place for up to 2 weeks and parents
Pediatric Hand Therapy • 395 are instructed to keep the dressing dry and clean. The dressing maintains pressure on the grafts. Extra pressure may be applied with wrapping or foam, as well as a positional splint. The first dressing change may be under anesthesia for the comfort of the child. Compression is maintained at all times (Figs. 17-34 to 17-36). At 2 to 4 weeks postoperatively when the wounds are generally healed, pressure molds are made to compress the scar. These molds are held in place either by an elastic wrap or a positional splint depending on the clinical manifestation of the hand. Splints may be as small as the scar mold, secured with straps, or as large as a long arm splint to help maintain position in a young or uncooperative child. Younger children have fat around the hand, making splint stabilization and pressure placement on the scar challenging. Splinting
Figure 17-36 foam.
Syndactyly, complete wrap over pressure
should be specific to each child, keeping in mind not only where pressure is needed, but also positional issues that may be present with the digits. Strapping should be carefully placed to discourage rotational deformities or flexion contractures. With good circulation in the flap or grafts, gentle ROM may be initiated. In addition, the child and parents or guardians are educated about how to care for the wounds, change the dressing if necessary, and maintain the hand to prevent or minimize edema; also, the child is encouraged to wear his or her molds and splints.
Phase III Figure 17-34
Syndactyly, after release.
Figure 17-35
Syndactyly, pressure foam.
Scars may continue to heal for up to 12 months or longer after injury. Attention should be given to scar management for as long as there is active scarring. This may take the form of night splinting with pressure molds and day pressure wraps. These wraps can be made in a variety of colors and can include just the affected digit(s) or the whole hand. Always leave the tip of the finger open to monitor circulation. With any pressure application, the parents must be taught to look at the color of the exposed tip to make sure the wrap is not too tight (Fuller, 1999). Strengthening exercises and desensitization activities should be incorporated into the child’s home program, and the use of the affected digits should be encouraged. In some cases, sensory re-education should be included. The child also should be encouraged to use the hand in functional patterns; this can take the form of games and ADLs, as well as playing with toys that facilitate dexterity. In each stage of healing an evaluation should be done before the initiation of therapy, and at regular intervals thereafter. The scar can be monitored through
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pictures, as well as specific measurements of depth, size, and color.
Clinical Implications Children that have had syndactyly releases should be seen in therapy for positioning and scar management immediately postoperatively. AROM and functional patterning should be initiated as soon as the grafts or flaps are healed.
RADIAL C LUB HAND Radial club hand belongs under category I of the International Federation of Societies for Surgery of the Hand, “failure of formation of the parts, longitudinalradial,” also known as radial ray deficiency or radial dysplasia. It is a complex congenital difference of the radial or preaxial border of the upper extremity. Radial dysplasia may present with a spectrum of abnormalities, varying in severity from a slight hypoplastic radius and minor thumb hypoplasia to aplasia of the radius, thumb, first metacarpal, scaphoid, trapezium, and all related soft tissues. Bayne and Klug (1987) categorized radial club hand into four categories, I through IV: short radius, hypoplastic radius, partial absence of the radius, and total absence of the radius, respectively. The child presents with a shortened extremity and a hand that is radially deviated at the distal end of a bowed forearm (D’Arcangelo, Gupta, & Scheker, 2000) (Figure 17-37).
Function Functional limitations vary based on the severity of the radial club hand, as well as the child’s age and adaptation to the condition and environment. Clinicians must be cautious not to assume functional limitations based
Figure 17-37
Radial club hand x-ray.
on the upper limb appearance alone, but rather on an individualized ADL evaluation. Impairment may be present in the elbow, with limited flexion. Wrist and finger motion is restricted secondary to the position of the hand, as well as to the deforming forces of the flexors that pull the hand into palmar displacement and radial deviation. With absence of the thumb in many cases, pinch patterns are performed between the long fingers with the most range. The child may use the hand against the forearm for gross grasp, because of the significant deviation at the wrist; this is a functional pattern for some. This action may be helpful to the child, although it may not look cosmetically appealing. The length discrepancy of the limb can create some difficulty with bilateral activities. Children with unilateral deficit adjust quite well and thus have minimal functional loss compared with children with bilateral involvement (Manske & McCarroll, 1998).
Evaluation of Radial Club Hand: Preoperative and Postoperative The preoperative evaluation should include assessment of ROM of the elbow, wrist, and hand, noting the position of the forearm, which is usually static. Specific attention should be given to the amount of passive range available in centering the hand on the ulna, noting blanching of the skin and other signs of structural stress. A developmentally appropriate ADL assessment should be done with particular emphasis on self-care. Grasp and release patterns are recorded, looking at the child’s ability to manipulate and move objects of various sizes and weights. Children with an absent thumb have creative new prehension patterns that also should be recorded. The length of both extremities is measured because length affects how far the child can reach into the environment. When the elbow is stiff in extension, the radial deviation of the hand is often what allows the child to reach the mouth and perineum for toilet care. The amount of deviation needed for those functions should be recorded. Careful notation of the child’s sensation, ability to follow through with an activity, frustration level, and parental or guardian’s participation assists the clinician in treatment planning. Evaluation of this population ideally should be preoperative, with the therapist contributing to the surgical decisions. The therapist has an unusual opportunity to supply the surgical team with functional information that can help in the algorithm of treatment. Often, surgery is contraindicated if the child has adapted to the condition. When surgery is appropriate, preoperative and postoperative evaluations should be done to record progress and be repeated at regular intervals.
Pediatric Hand Therapy • 397 Care must be given not to make surgical decisions based on aesthetic pressure from the family that will not improve the child’s function. Postoperative evaluation differs slightly with the type of surgery performed. Examples of common surgical procedures are Ilizarov placement and centralization or pollicization for an absent or hypoplastic thumb. In each situation, the evaluation should record the child’s physical limitations (impairment level) and how they affect their function.
Treatment of Radial Club Hand: Preoperative and Postoperative There are three options for addressing this condition: no treatment, conservative treatment, or surgical correction. The primary goal of treatment is to improve the overall function of the extremity. Cosmesis is a secondary consideration. Children with Type I or II of Bayne and Klug’s classification can be treated conservatively, with treatment starting a few days after birth. The child’s wrists are passively stretched into a centralized position, and the elbow is passively ranged. Parents or guardians are instructed in stretching and ranging activities. In between stretching, an above-elbow splint is applied, placing the elbow in 90 degrees of flexion and the wrist in a centralized position. If the soft tissues present with particular tightness, a serial casting regimen can be implemented. The cast should place the wrist in neutral with the elbow in 90 degrees of flexion. The cast can be changed a few days up to 2 weeks at a time. Once the desired position is attained, splinting at night and stretching by day should continue until bone maturity, which occurs in adolescence (D’Arcangelo et al., 2000; Manske & McCarroll, 1998). Kennedy (1996) describes a neoprene wrist brace designed for children as young as 3 weeks old. This brace is designed to minimize pressure points and disabling forces that are so common in these cases, by reinforcing the ulnar and radial sides with thermoplastic material. The reinforcers can be serially adjusted to achieve a neutral wrist. This study reports that passive correction may be easier to obtain in babies, but this brace also can be used successfully, in a serial manner, with older children before surgery. Infants also can be treated with taping, which is easier to apply than a splint; however, caution must be observed not to injure the skin. Conservative treatment of older children is determined by their functional ability. With mild wrist deviation, long-term splinting may help centralize the wrist; however, the deforming forces will still be present and thus usually some type of surgical intervention to maintain the position may be warranted. Splinting can
be used to mimic wrist position before surgery. The child can give his or her opinion of the wrist position. Splinting for radial club hand can take many forms. The author’s recommendation is a three-point pressure design, with one point at the ulnar side of the proximal forearm, the other on the ulnar side of the palm, with the third point being in opposition right at the distal end of the ulna, radial side (at the wrist). Depending on the age of the child and condition of the elbow, the splint design may be above the elbow, with the elbow kept at 90 degrees of flexion, although the elbow is left free when possible. If the thumb is present, it is also left free (Figure 17-38). Children and parents or guardians are educated in ROM and stretching exercises of the elbow, wrist, and digits. Shoulder active ROM also is included. Digital flexion may be compromised because of the limited excursion of the flexors. This can be improved with positioning and exercise. Prolonged stretch may be uncomfortable for the child; therefore parents or guardians should be instructed carefully about keeping the discomfort to a minimum and the importance of the daily stretches (Fuller, 1999). When a surgical correction is performed for centralization of the hand, the child generally is placed in a cast. Once the cast is removed, a splint is made and therapy can begin. However, first information should be obtained about the surgical procedures, specifically what tendons were transposed. Therapy generally combines the following procedures: 1. Fabricating a splint, similar to the one described in earlier, to maintain position until skeletal maturity is achieved. Splint is adjusted on a regular basis. 2. Protecting and re-educating the transposed tendons, usually flexor carpi ulnaris
Figure 17-38
Radial club hand splint.
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3. Increasing ROM once the child is cleared to move the involved extremity 4. Re-education of prehension patterns and functional tasks 5. Scar and edema management 6. Providing the child with appropriate assistive devices and adaptations Starting with the initial visit to therapy, the child is instructed in patterning for independent function that is age appropriate. Adaptive use of the hand is encouraged with emphasis on elbow motion and digital prehension. Bilateral activities are encouraged, as is manipulation and grasp and release activities in a graded manner. Play activities are encouraged.
External Fixation with an Ilizarov Kessler (1989) introduced the Ilizarov, an external fixator that gradually distracts the soft tissue, approximately 1 to 2 mm a day, slowly achieving a better wrist position, with minimal to no neurovascular compromise. The device is used preoperatively and may be on the child’s hand for several weeks. During this period, therapy should emphasize ROM of all uninvolved joints. Because of the weight of the device, an excellent medium for exercise is a therapeutic pool. The child can move the shoulder and elbow with or without the therapist’s assistance in the water, aiding the affected arm with the non-affected one. Fingers can be stretched with dynamic splinting that is fabricated on the Ilizarov. Dynamic extension splinting can aid in reducing any flexion contractures, as well as provide proprioceptive input for flexor excursion. The hand can be supported with a static night splint to maintain functional positioning of the digits (Figure 17-39).
Clinical Implications When treating a child with congenital differences, the assessment should be based on the specific child and his or her adaptation, rather than typical children of the same age. Often children adapt beautifully to their differences and minimal intervention is necessary.
SUMMARY This chapter has provided a base line for the healing process for common injuries or surgical interventions. The process of evaluation also has been discussed, as well as common treatment protocols. With each injury or condition the actual treatment plan is individualized to the specific child and his or her special situation based on the evaluation. Knowledge of normal development, normal healing, and good observation skills may be the most valuable evaluation tools, especially with infants and small children. Gaining the child’s trust and helping him or her overcome fear is the first step in therapy. After an injury or surgery, the child may regress in development and adaptive skills. The parents or guardians also may be fearful and confused as to what is happening to the child. Each child presents with unique qualities. When determining a treatment plan, these qualities are considered, along with the child’s home environment, diagnosis, and the type of medical intervention received. Realistic functional goals are then formulated that are specific to that child. Children are resilient and bring new meaning to the notion of “what is possible” rather than “impossible.”
REFERENCES
Figure 17-39
Ilizarov for a radial club hand.
Aaron DH, Stegink Jansen CW (2003). Development of the functional dexterity test (FDT): Construction, validity, reliability, and normative data. Journal of Hand Therapy, 16(1):12–21. Adams LS, Greene LW, Topoozian E (1992). Range of motion. Clinical assessment recommendations, 2nd ed. Chicago, American Society of Hand Therapists. al-Quattan MM, Posnick JC, Lin KY, et al. (1993). Fetal tendon healing development of an experimental model. Plastic and Reconstructive Surgery, 92(6):1155–1160. Apfel ER, Carramza J (1992). Functional limitation level evaluation: Dexterity. Clinical assessment recommendations, 2nd ed. Chicago, American Society of Hand Therapists. Aulicino PL (2002). Clinical examination of the hand. In EJ Macking, AD Callahan, TM Skirven, LH Schneider, AL Osterman, JM Hunter, editors: Rehabilitation of the hand and upper extremity (pp. 311–330). St Louis, Mosby. Baldwin JE, Weber LJ, Simon CL (1992). Wound and scar. Clinical assessment recommendations, 2nd ed. Chicago, American Society of Hand Therapists.
Pediatric Hand Therapy • 399 Barillo DJ, Harvey KD, Hobbs CL, Mozingo DW, Coiffi WG, Pruitt BA (1997). Prospective outcome analysis of a protocol for the surgical and rehabilitative management of burns to the hand. Plastic and Reconstructive Surgery, 100(6):1442–1451. Bayne LG, Klug MS (1987). Long-term review of the surgical treatment of radial deficiencies. Journal of Hand Surgery, 12A(2):169–176. Bear-Lehman J, Kafko M, Mah L, Mosquera L, Reilly B (2002). An exploratory look at hand strength and hand size among preschoolers. Journal of Hand Therapy, 15(4):340–346. Beatty E, Light TR, Belsole RJ, Ogden JA (1990). Hand clinics, the pediatric upper extremity. Philadelphia, WB Saunders. Binfield PM, Sott-Miknas A, Good CJ (1998). Median nerve compression associated with displaced Salter-Harris type II distal radial epiphyseal fracture. Injury, 29(2):93–94. Brennen MD, Fogarty BJ (2004). Island flap reconstructin of the web space in congenital incomplete syndactyly. Journal of Hand Surgery (Br), 29(4):377–380. Callahan AD (2002). Sensibility assessment for nerve lesions-in-continuity and nerve lacerations. In EJ Macking, AD Callahan, TM Skirven, LH Schneider, AL Osterman, JM Hunter, editors: Rehabilitation of the hand and upper extremity (pp. 214–239). St Louis, Mosby. Clarke HM, Wittpen GP, McLeod AM, Candlish SE, Guernesy CJ, Zuker RM (1990). Acute management of pediatric hand burns. Hand Clinics, 6(2):221–232. Couch KJ, Deitz JC, Kanny EM (1998). The role of play in pediatric occupational therapy. American Journal of Occupational Therapy, 52(2):111–117. D’Arcangelo M, Gupta A, Scheker LR (2000). Radial club hand. In A Gupta, SPJ Kay, LRL Scheker, editors: The growing hand, diagnosis and management of the upper extremity in children (pp. 147–170). St Louis, Mosby. Damore DT, Metzl JD, Ramundo M, Pan S, Van Amergongen R (2003). Patterns in childhood sport injury. Pediatric Emergency Care, 19(2):65–67. Dao KD, Shin AY, Billings A, Oberg KC, Wood VE (2004). Surgical treatment of congenital syndactyly of the hand. Journal of the American Academy of Orthopedic Surgery, 12(1):39–48. Davis JL, Crick JC (1988). Pediatric hand injuries. Type and general treatment considerations. AORN Journal, 48(2):237–239, 242–235, 248–249. de Chaliain T, Clarke HM (2000). Thermal and chemical injuries. In A Gupta, SPJ Kay, LRL Scheker, editors: The growing hand, diagnosis and management of the upper extremity in children (pp. 665–692). St Louis, Mosby. Dunst C, Scott EC, Karaats JJ, Anderson PM, Twomey JA, Pelteir GL (2004). Contact palm burns in toddlers from glass enclosed fireplaces. Journal of Burn Care Rehabilitation, 25(1):67–70. Ebinger T, Fischer A, Katzmair P, Wachter NJ, Traub SE, Gulke J, Mentzel M (2003). Treatment of flexor tendon injuries in children. Handchir mikorchir plast chir 35(6):353–357. Evans R (2002). Clinical management of extensor tendon injuries. In EJ Macking, AD Callahan, TM Skirven, LH Schneider, AL Osterman, JM Hunter, editors: Rehabilitation of the hand and upper extremity (pp. 542–579). St Louis, Mosby.
Evans RB, McAuliffe JA (2002). Wound classification and management. In EJ Macking, AD Callahan, TM Skirven, LH Schneider, AL Osterman, JM Hunter, editors: Rehabilitation of the hand and upper extremity (pp. 311–330). St Louis, Mosby. Exner CE (1992). In -hand manipulation skills. In J CaseSmith, C Pehoski, editors: Development of hand skills in the child. Rockville, MD, American Occupational Therapy Association. Fasching G, Schmidt B, Friedrich H, Mayr J (1998). Dynamic splinting after flexor tendon injuries of the hand in childhood. Handchir mikorchir plast chir, 30(4):243–248. Favetto JM, Rosenthal AI, Shatford RA, Kleinert HE (2000). Tendon injuries in children. St Louis, Mosby. Fetter-Zarzeka A, Joseph MM (2002). Hand and finger injuries in children. Pediatric Emergency Care, 18(5):34–105. Friedrich H, Baumel D (2003). The treatment of flexor tendon injuries in children. Handchir mikorchir plast chir, 35(6):347–352. Fuller M (1999). Treatment of congenital differences of the upper extremity: Therapist perspective. Journal of Hand Therapy, 12(2):174–177. Graham TJ, Hastings H (2000). Fracture and dislocations in the child’s hand. In A Gupta, SPJ Kay, LRL Scheker, editors: The growing hand: Diagnosis and management of the upper extremity in children (pp. 591–607). St Louis, Mosby. Greenhigh DG (2000). Management of acute burn injuries of the upper extremity in the pediatric population. Hand Clinics, 16(2):175–186. Grobbelaar AO, Hudson DA (1994). Flexor tendon injuries in children. Journal of Hand Surgery (Br), 19(6):696–698. Hager-Ross C, Rosblad B (2002). Norms for grip strength in children aged 4–16. Acta Paediatrica, 91(6):617–625. Hastings H, Simmons BP (1984). Hand fractures in children. A statistical analysis. Clinical Orthopedics, 188:120–130. Hicks CL, von Baeyer CL, Spafford P, van Korlaar I, Goodenough B (2001). The faces pain scale-revised: Toward a common metric in pediatric pain measurement. Pain, 93:173–183. Kayli C, Eren A, Agus H, Arslantas M, Ozcalabi IT (2003). The results of primary repair and early passive rehabilitation in zone II flexor tendon injuries in children. Acta Orthop Traumatol Turc, 37(3):249–253. Kennedy SM (1996). Neoprene wrist brace for correction of radial club hand in children. Journal of Hand Therapy, 9(4):348–390. Kessler I (1989). Centralization of the radial club hand by gradual distraction. Journal of Bone and Joint Surgery, 14B(1):37–42. Le TB, Hentz VR (2000). Hand and wrist injuries in young adults. Hand Clinics, 16(4):597–607. Lee-Valkov PM, Aaron DH, Eladoumikdachi F, Thornby J, Netcher DT (2003). Measuring normal hand dexterity values in normal 3-, 4-, and 5-year-old children and their relationship with grip and pinch strength. Journal of Hand Therapy, 16(1):22–28. Lourie GM (1999). Treatment of congenital differences of the upper extremity: Surgeon’s perspective. Journal of Hand Therapy, 12(2):164–173.
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Mahabir RC, Kazemi AR, Cannon WG, Courtemanche DJ (2001). Pediatric Emergency Care, 17(3):153–156. Manske PR, McCarroll HR Jr (1998). Radial club hand. In D Buck-Gramcko, editor: Congenital malformations of the hand and forearm (pp. 433–447). Philadelphia, Churchill Livingstone. Mathiowets V, Wiemer DM, Federman SM (1986). Grip and pinch strength: Norms for 6- to 19-year-olds. American Journal of Occupational Therapy, 40(10):705–711. Maurer GL, Jezek SM (1992). Clinical assessment recommendations, 2nd ed. Chicago, American Society of Hand Therapists. McCauley RL (2000). Reconstruction of the pediatric burned hand. Hand Clinics, 16(2):249–259. Mulder GD, Brazinsky BA (1995). Factors complicating wound repair. In JM McCulloch, LC Kloth, JA Feedar, editors: Wound healing alternatives in management (pp. 47–59). Philadelphia, FA Davis. Penttengill KM, van Strien G (2002). Postoperative management of flexor tendon injuries. In EJ Mackin, AD Callahan, TM Skirven, LH Schneider, AL Osterman, JM Hunter, editors: Rehabilitation of the hand and upper extremity (pp. 431–456). St Louis, Mosby. Pratt PN, Allen AS, Carrasco RC, Clark F, Schanzenbacher KE (1989). Instruments to evaluate component functions of behavior. In PN Pratt, AS Allen, editors: Occupational therapy for children (pp. 168–217). St Louis, Mosby. Pryde JA (2003). Inflammation and tissue repair. In MH Cameron, editor: Physical agents in rehabilitation, from research to practice (pp. 13–37). St Louis, Saunders. Roberts L, Alvarada MI, McElory K, Rutan RL, Dasai MH, Herndon D, Robertson MC (1993). Longitudinal hand
grip and pinch strength recovery in the child with burns. Journal of Burn Care Rehabilitation, 14(1):99–101. Sheridan RL, Baryza MJ, Pessina MA, O’Neill KM, Cipullo HM, Donela MB, et al. (1999). Acute hand burns in children: Management and long-term outcomes based on a 10-year experience with 698 injured hands. Annals of Surgery, 229(4):558–564. Shortridge SD (1989). The developmental process: Prenatal to adolescence. In Occupational therapy for children. St Louis, Mosby. Shuaib I (1997). Fracture of the proximal phalanx of the little finger in children: classification and method to measure the deformity. Canada Journal of Surgery, 40(5):363–367. Smith KL (1992). Wound healing. In BG Stanley, SM Tribuzi, editors: Concepts in hand rehabilitation (pp. 35–58). Philadelphia, Davis. Smith P, Laing H (2000) Syndactyly. In A Gupta, SPJ Kay, LRL Scheker, editors: The growing hand, diagnosis and management of the upper extremity in children (pp. 225–230). St Louis, Mosby. Swanson AB, Swanson GD, Tada KA (1983). A classification for congenital limb malformation. Journal of Hand Surgery, 8(5):693–702. Ward RS, Schnebly WA, Karvitz M, Warden GD, Saffle JR (1998). Have you tried the sandwich splint? A method of preventing hand deformities in children. Journal of Burn Care Rehabilitation, 10(1):83–85. Zimmermann R, Gschwentner M, Kralinger F, Arora R, Gabl M, Pechla S (2004). Long-term results after pediatric distal forearm fractures. Archive of Orthopedic Trauma Surgery, 124(3):179–186.
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18
SPLINTING THE UPPER EXTREMITY OF A CHILD Kimberly Brace Granhaug
CHAPTER OUTLINE
GENERAL CONSIDERATIONS IN PEDIATRIC HAND SPLINTING
SPLINTING PRINCIPLES
Wearing Schedule for Pediatric Splints
BENEFITS AND GOALS OF SPLINTING SPLINT SELECTION Problem-Based Splint Selection Type of Splint: Static, Serial Static, Static Progressive or Dynamic? Material Selection for Low Temperature Thermoplastics Splint Fabrication for the Child SPLINTING FOR COMMON PEDIATRIC HAND PROBLEMS Thumb in Palm Fisted Hand Wrist Flexion Wrist Ulnar Deviation Wrist Radial Deviation Supination and Pronation Weight Bearing on the Upper Extremities Individual Finger Control Splinting Infants in the Neonatal Intensive Care Unit SPLINTING FOR PEDIATRIC ORTHOPEDIC PROBLEMS Fractures Flexor Tendon Splinting in Children Juvenile Arthritis Brachial Plexus Injury and Peripheral Nerve Injury
Complications and Precautions SUMMARY CASE STUDY: A child with Radial Nerve Palsy APPENDICES “Splinting is the intentional application of external loads to specific anatomic structures to manipulate the internal reaction forces and thus enhance or restore function of the extremity” (Austin, 2003, p. 59).
Splinting is an ancient art. It has been practiced for thousands of years, as the Egyptians used twigs, reeds, and vines for fracture stabilization (Fess, 2002a). There are many tried and true splint designs; however, “Of paramount importance is the understanding that there are no rote splinting solutions to combating pathologic conditions of the hand. Splints must be individually created to meet the unique needs of each patient, as evidenced by designs that incorporate the variable factors of anatomy, physiology, kinesiology, pathology, rehabilitation goals, occupation, and psychological status” (Fess, 2002b, p. 1818).
The most important reason to apply a splint on a child is to improve function. Of course there are other primary reasons and secondary benefits such as to improve joint range of motion, decrease joint stiffness and contractures, improve hygiene, and modify behavior. Dysfunction or deficits in the upper extremity pediatric population can be divided into three major groups: infants and children with congenital or birth injuries that require splinting to prevent development of deformity or correct existing deformities, children
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with congenital defect who have undergone corrective surgery, and those who require treatment secondary to pathology or trauma (Byron, 2002). Splinting and postoperative protocols are more standardized for orthopedic involved cases as compared to splinting and protocols for neurological involvement. It is beyond the scope of this chapter to cover the numerous splint designs and fabrication instructions for multiple diagnoses. Instead, an overview of splint decision making, as well as splint ideas, is the focus. It must be appreciated that the plasticity and immaturity of a child’s system allows gentle forces to both promote developmental hand function, as well as potentially result in harmful effects. It is important to realize both the structural and developmental differences in a child’s hand when splints are being applied. Developmentally disabled children have not experienced normal hand function or weight bearing and consequently lack the normal configuration of arches and grasping patterns (Hogan & Uditsky, 1998). Therefore splints should support the normal configurations, as well as promote functional developmental grasp and release patterns. Special care needs to be taken with the child who is nonverbal because of age or disability who may experience problems with decreased sensitivity, tactile defensiveness, and splint pressure. The immature or youthful lack of experience with normal motion and function also requires observation, consideration, and instruction for the child or parents.
SPLINTING PRINCIPLES Mechanical principles used in splinting adults and children are the same. Once the concepts of the anatomical and mechanical principles are understood there is little requirement for splint patterns. Applying the softened splint material and positioning the hand and affected joints in the desired and optimal biomechanical position for the purpose the splint is intended are the keys to effective splinting. Generally, the experienced therapist uses less splint material without a pattern than a novice splinter with a pattern because it takes both perception of what the splint will do and what forces the splint will exert, as well as the vision of how the splint will accomplish this to be an effective and efficient splint maker. The splint is used to place body parts into the most beneficial position for the preestablished goal with proper biomechanics considered for the extremity, injury, and splint. The mechanical principles that must be understood and applied include force, pressure, torque, friction, and shear stress. Obviously an entire chapter could be dedicated to biomechanics and mechanical principles; instead an overview of the important mechanical prin-
ciples as they relate to splinting is discussed. Fess and co-workers (2005) were thorough in their discussion of biomechanics of the hand and splint design, fabrication, and execution. It has long been considered the “splinting bible”; any therapists contemplating splint design should be aware of these principles (Fess et al., 2005). Some understanding of basic physics and mechanical principles help with splint design, both from an effectiveness and aesthetic standpoint, and can help the splint look “cool,” an important aspect in convincing children to wear one. It is critical to understand that pressure is actually the force that is being applied by the splint material, through gravity and dynamic tension, multiplied by the area over which the force is being distributed. In effect, splints covering a larger area disperse force or load over a greater area and reduce pressure and occurrence of skin breakdown. Also, the more conforming the splint, the less room there is for friction and pressure points to build. The rule of thumb in maintaining the proper amount of pressure from the splint material and straps is that the splint should cover two-thirds of the length of the forearm or limb and one half the circumference of the limb or body part. This maximizes pressure distribution and splint stability and minimizes pressure points and migration of the splint. Wider splint straps also distribute pressure more evenly than narrower straps. Common pressure points both for splint material and strapping are included in this sketch (Figure 18-1). Another important principle in splinting is torque. Torque is a rotational force and can be beneficial or destructive. When applying torque it should be at 90 degrees to the segment being mobilized. Without the correct line of pull in a dynamic situation, the skin suffers with shear forces; the result is unnecessary pain, unwanted torque on the joint, and possibly even skin 1
4
9 2
5 2
3 6
8 9
Figure 18-1 Areas prone to pressure because of splint or strap force include: (1) dorsal metacarpals, especially with dorsally based splints; (2) volar surface of metacarpals and thumb at distal end of wrist cock-up splints and C-bars; (3) volar surface of digits with resting hand splints resulting from spasticity or contractures; (4) dorsal surface of first phalanges and proximal interphalangeal joints; (5) ulnar styloid; (6) thumb metacarpal; (7) not shown, but center of the palm with too much transverse arch in the palm; (8) base of the thumb with vulnerable radial nerve; (9) proximal end of the splint. (From Malik M [1985]. Manual on static hand splinting. Pittsburgh, AREN.)
Splinting the Upper Extremity of a Child • 403 breakdown. Splints must be considered lever mechanisms. Force applied in one area results in force and pressure in another area, similar to a shovel. Pushing down on the handle creates a force in the opposite direction on the scooping end of the shovel. Similarly, the force of wrist flexion can cause a short splint to dig into the forearm, or a dorsally based splint to dig into the metacarpals. Use contours and curves to add strength to the design of a splint. For example, a piece of flat sheet metal wobbles and oscillates; yet can withstand heavy loads when curved (e.g., a drainage gutter or car fender). The same is true with forearm-based wrist cock-up splints and outriggers. Curves add strength and if used well in a design can also add to the aesthetics. Steel beams for buildings are in the shape of an I or T to add strength to the structure. Flat beams are not nearly as strong for support. To build in strength without adding several layers of splint material, add an I- or T-shaped bar of splint material to the weak area. It is not necessary to be a mechanical engineer to construct a splint, but basic mechanical and physics principles take one a long way in designing the optimal splint for the child. According to Fess and co-workers (2005), the general principles of design that play an important role in splint design must take individual patient factors, such as age and intellect, into account. Also, one must consider the high activity and energy level of a child; this alone requires that splints must be durable, as well as nontoxic and easily cleaned. The length of time the splint is to be used is also a factor in design. “In general the shorter the anticipated need of the splint, the simpler its design, material type, and construction should be” (Fess et al., 2005, p. 211).
Strive for simplicity and pleasing appearance. Some patients have low “gadget tolerance” and are much more accepting and compliant with a simple, cosmetically pleasing splint. Children also tend to be more compliant if they are involved in helping to choose a color or favorite sticker to decorate the splint. Allow for optimum function of the extremity without needless immobility of the uninvolved joint, unless it is necessary to secure the splint to prevent removal. Children are less likely to suffer stiff joints for a prolonged period if proximal joints are used to stabilize or secure the splint from removal by the child (Figure 18-2). Allow for optimum sensation: “Without sensation the hand is perceptively blind and functionally limited . . . splint designs should leave as much of the palmar tactile surface areas as free from occlusive material as possible” (Fess et al., 2005, p. 213).
Figure 18-2 Splints should include proximal joints to assist in splint stability and decrease the probability that they will be removed.
Allow for efficient construction and fit. Plan design to limit construction time and readjustment; sometimes prefabricated splints are the most reasonable, especially when time and expenses are considered. Provide for ease of application and removal. Independent donning and doffing of splints improve compliance; caretakers of small children also need quick and efficient means of fastening and unfastening splints for application and removal. Consider the splint or exercise regimen: It may be possible to have both flexion and extension systems built into the same splint (Van Straten & Sagi, 2000). Similarly, a long arm thumb spica may be trimmed to a hand-based thumb spica as therapy and healing progress. The cost factor also should be considered at this point. Finally, the splint should be safe from hard or sharp edges, as well as any attachments or straps that may come off or be swallowed.
BENEFITS AND GOALS OF SPLINTING Establish the potential benefits and goals of splinting (Box 18-1). Positioning is an important part of both rest and active play. Because the upper extremities are so vital to self-care, feeding, and sensory input, the placement of the fingers, hands, wrists, and forearms is crucial to development and life functions. Splinting used for positioning is usually static, but also may have a dynamic component. The goals for a positioning splint are to mobilize joints, stretch soft tissues, reduce contractures, provide stability or support at specific joints, provide proper alignment, and prevent deformity. As stated, the development of self-care and
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BOX 18-1
Potential Goals and Benefits of Splinting
Position Function Hygiene Protection and behavior
exploration in the child centers around the use of his or her upper extremities. Other goals for a positional splint include enabling or improving existing function, augmenting the benefits of therapy, and substituting for weak or absent muscles. Functional splinting may be used to hold or adapt eating or writing instruments, as well as to aid in the management of assistive technology for environmental controls or educational access. This may be attained through isolation of a digit for pointing and touching a keyboard or creating a flat palm to access a touch pad for a fan or light switch. On the other hand, a custom fabricated joy stick gripping splint may mean increased independence of computer use or may improve accuracy in controlling an electric wheelchair for a child with a neurologically involved hand. Also, a hand-based thumb spica splint may be the key to thumb control that a child requires to manipulate clothing, fasteners, or a pencil. Another potential goal is to improve or prevent hygiene problems. This is usually more of an issue with the neurologically involved hypertonic hand. The difficulty of relaxing the hand to allow air flow and hand washing can be assisted through splinting for hand position, as well as protection of the palmar surface. Finally, splinting goals can be to help modify or prevent undesired behaviors that interfere with safety or upper extremity use. This might include, but is not limited to, elbow extension splinting to keep the hands away from the mouth or necessary life support equipment or medical equipment in use with the child. In some cases splinting and behavior modification can be tools to improve self-injurious behavior (Hogan & Uditsky, 1998). Orthopedic or post trauma splinting is discussed later in the chapter.
SPLINT SELECTION THE PROBLEM-BASED SPLINT SELECTION C HART Hogan and Uditsky (1998) have developed a priority rating form, as well as a splint selection flow chart (Figure 18-3), which is helpful for determining the
priority of needs of the child. Table 18-1 is also helpful and is an adaptation of another chart by the same authors that lists the proper splint to fabricate for specific needs. Generally, the shotgun splinting approach of trying to fix too many problems at once ends up not benefiting any one problem well. For example, a child may need to open the hand for weight bearing, abduct the thumb for fine motor grasp, and pinch and extend the wrist to improve hand biomechanics. It may not be possible to achieve all of this through one splint without causing undue pressure or constriction. Therefore usually it is better to have splints for different functions. The problem-based splinting chart is organized to help plan splint selection around the child’s problem and not diagnosis; look at the “problem” and not just the diagnosis when deciding splint design. It is of the utmost importance to observe the child’s pattern of movement and grasp while playing or moving, because children with abnormal tone adapt substitution patterns that may be functional. A splint may limit the functional movement and affect hand use in a negative way. Problem solve first, and then create the splint!
TYPE OF SPLINT: STATIC, SERIAL STATIC, STATIC PROGRESSIVE, OR DYNAMIC? Static splints are the most commonly made and one of the most important splints. Static splinting is nonarticular, with no moving parts. It is basically an immobilization or supportive splint, but may be used to control mobilization or encourage mobilization by the joints it is blocking or not blocking. Finger gutter, wrist cock-up, thumb spica, and resting hand splints are examples of static splints (Figure 18-4). Serial static splints are static splints that are periodically remolded and reapplied as the joint gains motion or the tissue gains length. They are applied at the end range with the joint stretched maximally. Serial casting is a good example of this. It may be used to promote proximal interphalangeal (PIP) extension with flexion contractures (Figure 18-5). A night time elbow extension splint may be used in the same way for an elbow flexion contracture. Static progressive splints use nonelastic components with low load in a single direction over a long period of time to mobilize soft tissue at its end range of motion (ROM) so that it accommodates to the new length. The use of nylon monofilament, inelastic strapping, hinges, screws, turnbuckles, and MERiT or Splint Tuner components (Figure 18-6), without the use of rubber bands and elastic materials, slowly changes the resting length of soft tissue with the joint in a static, stretched position over a prolonged amount of time (Austin & Jacobs, 2003). Most often static-progressive
Splinting the Upper Extremity of a Child • 405
Figure 18-3 The Pediatric Splint Selection Flow Chart. (From: Hogan T & Uditsky T [1998]. Pediatric splinting: Selection, fabrication, and clinical application of upper extremity splints. San Antonio, TX, Therapy Skill Builders. p. 20.)
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Table 18-1
Problem-based splint selection
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Table 18-1
Problem-based splint selection—cont’d
(Modified from: Hogan L & Uditsky T [1998]. Pediatric splinting: Selection, fabrication, and clinical application for upper extremity splints. San Antonio, TX, Therapy Skill Builders. p. 31.)
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Figure 18-6 Static progressive splint. MERiT component used to progress wrist extension.
Figure 18-4
Static splint: finger gutter.
Figure 18-7 Dynamic splint. Used here as an exercise splint to increase strength and proprioceptive input at the distal interphalangeal joint after a flexor digitorum profundus repair.
of the traction. Through the continuum of healing there are basic guidelines for splint selection. Note that joint, injury, or contracture fit into these categories; however, it is a basic rule of thumb that may help you decide what splint design the child needs. Constant reassessment of tissue healing, joint motion, growth, and splint fit are important to maximize the positive aspects of the splint and minimize the negative effects that are possible when applying a splint to the extremity of a child (Figure 18-8). Paul Brand, a pioneer in hand surgery and hand therapy, lists the 10 questions one should ask before dynamic splints are made. Figure 18-5 Serial static splint. This splint can be reapplied as the joints improve range of motion.
splinting is custom made, although some components may be prefabricated and kits are available. Dynamic splinting uses articulations and force components to constantly put a dynamic pull on the tight or healing tissue. Dynamic splinting uses the elastic properties of the tissue, as well as the splint components such as rubber bands, springs, or elastic cord, to exert controlled mobilization (Figure 18-7). It may be used conversely to strengthen or give proprioceptive feedback when exercise is done against the line of pull
“. . . the first step is to define the object of the dynamic splint for the specific hand we are treating and for the specific joint or joints that we want to mobilize or modify. Then we should ask 10 questions in relation to the forces we propose to use: (1) How much force? (2) Through what surface? (3) For how long? (4) To what structure? (5) By what leverage? (6) Against what reaction? (7) For what purpose? (8) Measured by what scale? (9) Avoiding what harm? and (10) Warned by what signs?” (Brand, 2002, pp. 1811-1817).
These principles seem simple; however, they make the difference between a successful, well-designed dynamic splint and a disaster that has potential to harm the child.
Splinting the Upper Extremity of a Child • 409 Inflammation
Proliferative
Remodeling
Immobilization o Static Mobilization ← o Dynamic o Serial Static → o Static Progressive → Restriction ← o Static → ← o Dynamic →
Figure 18-8 Tissue is in constant change when healing, always moving between stages. Observe tissue healing and scar maturation when considering which type of splint to use, and constantly re-evaluate tissue change and splint effectiveness. (Modified from Jacobs M, Austin N [2003]. Splinting the hand and upper extremity: Principles and process. Philadelphia, Lippincott Williams & Wilkins.)
MATERIAL SELECTION FOR LOW TEMPERATURE THERMOPLASTICS A multitude of splint materials are on the market and it would be difficult for anyone to fabricate all custom designed splints with one material in one thickness. The therapist will likely get the best splint for the individual if thought is put into the choice of splint material. Materials have six major qualities or handling characteristics that affect splint fabrication including drapability or conformity, stretch, memory, bonding, rigidity, and handling or set time (Box 18-2). Drapability or conformity is the degree at which the material takes the shape of the contours below it. High drapability or conformity material makes intimate contact with the contours of the wrist, metacarpals, and digits; on the other hand, it is easy to apply too much pressure and get deep imprints that may cause pressure and are not easily removed. Low drapability material needs more handling to conform to the contours beneath it. Overheated material also can result in too much
BOX 18-2
Splint Material Characteristics
Drapability and conformability Stretch Memory Bondability Rigidity Working times and heating Other Thickness Perforations Color
drapability; therefore, watch heating time. A high drapable material is Polyform; midrange materials are Polyflex II, TailorSplint, and Orfit; and low drapable materials are Synergy and Orthoplast. Highly drapable materials should be handled in the horizontal plane to prevent overstretching the material. The ability to stretch or resist stretch without buckling or loss of rigidity is another important characteristic that usually runs parallel to the amount of drapability a material has in it; the more drapability the easier the stretch, and vice versa. Around contours such as elbows and flexed metacarpals it is essential to have stretch without loss of strength or shape; however, too much drapability on a longer or larger splint can be difficult to control. Novice splinters may wish to start off with a midrange material such as Ezeform or Orfit. Memory is the degree to which a material will return to its original shape. Aquaplast has a high memory. It can be molded and fixed and dropped in the splint pan to return to its original shape. High memory is helpful if high tone or tactile sensitivity is an issue and the material may get “smushed” by a grasp reflex. It is excellent if the goal is serial splinting or if there will be a significant change in edema; however, memory can be a problem if the material is taken off the patient before it is fully cooled because it will shrink and try to return to its original shape as it cools. This in turn creates both a poor fit and edges that dig into the skin. Bondability, or the ability of the material to stick to itself when heated, is another property that must be weighed when choosing material. Material may have a coating that resists bonding and is easy to “pop” apart when cool. The coating may be left on and a damp paper towel or lotion can be used to help prevent bonding. Also, if bonding is desired for outrigger placement or sealing around the thenar web space, the coating can be removed with a solvent or scraped off with a sharp instrument. Rigidity is the relative amount of strength the material has when cool. The higher the rigidity the more the material resists passive bending and cracking. Higher rigidity is suggested for spasticity or long-term contractures. Rigidity also can be added to less rigid materials through contours, I- and T-beam supports, and multiple layering. Working time or setting time needs to be kept in mind when working with a material. Thin materials (1/16″) have a short working time and set quickly once removed from the splint pan. Other materials depending on the heating time and temperature and material qualities take up to 2 minutes to heat up and have 2 to 6 minutes of workable time before they set. Drying off the splint material also extends the working time because evaporation cools the material faster and less evenly.
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Each material also is made up of a different combination of plastic, rubber, and polymers and the qualities also are influenced by the thickness of the material. Materials come in 1/16″, 1/12″, 3/32″, and 1/8″ thickness. Most finger-based splints are made from the thinnest 1 /16″ materials to help reduce bulk between the fingers and they are strong enough to maintain the correct position in a finger. Children’s hand or wrist splints can be made from this material as well if spasticity is not an issue. However, hand, wrist, and forearm splints should be made from thicker materials so they will retain their strength across the joint. Other physical characteristics include the option of perforations, as well as color. Many splinting materials exist and new ones come on the market all the time. It is a good learning experience to have your local sales representative bring out or send you samples of the various materials in different thicknesses. Different splint property charts go into great detail about the materials, but the best way to find out how they will respond to your use of them is hands-on use. Play with the different materials and make the same splint out of several types and thicknesses of material. Use different strapping materials as well and you will find out what works best for the most common splint types you make. If you work in a busy hand clinic you most likely have several different types of materials in various thicknesses because of the wide variety of hand and upper extremity diagnoses seen. The school, itinerant, or home health therapist may find that he or she is making a similar type of splint for a similar age group and may select a couple of all-around good splint materials to have on hand. Remember not to leave them in the car! This is an expensive mistake for a traveling therapist, as the author learned from personal experience during one hot Texas summer. Soft splinting materials also are splints by definition. This includes, but is not limited to, Neoprene, Lycra, elastomer, strapping, and taping. Combinations of conventional splint and soft materials may be the best choice, depending on the specific needs of the child.
no longer essential. Make the splint material fit the design and the child’s hand; do not try to make the hand fit a preconceived pattern. Nearly all splints can be started as a rectangle. Once the heated soft rectangle of material has been placed on the hand or upper extremity, it is much more apparent where to cut, where to roll, and where not to cut. Too often the splint material is cut before it is applied to the child and too much material is already gone. Stretching to make up for lack of material can weaken the splint design. Begin by prepadding bony prominences, applying a stockinette (it may be wise to apply the padding on top of the stockinette as in Figure 18-9), positioning the child, and then applying the splint rectangle. With proper positioning and the help of gravity, it is possible to get good conformity and mark where the splint needs to be cut away. Having a little extra material beyond the conceived splint design can give the therapist extra leverage to help hold joints for position while the splint is being fabricated and it can be cut away when the essential part of the splint is set and cooled. Edge finishing is essential for comfort and safety, as well as attachment and outrigger security, especially for the infant and child. Attachments and straps should be considered harmful if swallowed; therefore permanent bonding or riveting may be needed. Commercially designed patterns for the more common splints are available and they can be shrunk in size with a copier for a more child-friendly version. However, the proportions of a child’s hand are not the same as those in an adult; forearms may be too long or there may be no allowance for the fat pads on the dorsum of an infant’s hand and fingers. Remember to fit the splint to the child’s needs and not the child to the splint pattern.
SPLINT FABRICATION FOR THE C HILD Because of the generally short attention span of a child with likely imperfect cooperation, time may be limited to make patterns, fit, refit, apply strapping, and provide adequate education. Reducing the child’s and parents’ anxiety through play can make the experience less of an ordeal. Having some age-appropriate games and distractions at hand can help (often the siblings need distraction). Realistically, once the goal(s) have been established, and the biomechanics and pathology have been understood and applied, the need for a pattern is
Figure 18-9 Prepadding the ulnar styloid and other critical areas (e.g., around percutaneous pins) helps avoid pressure areas.
Splinting the Upper Extremity of a Child • 411
SPLINTING FOR COMMON PEDIATRIC HAND PROBELMS THUMB IN PALM Many times with infants and small children the best splint is actually a strap or splint and strap combination to gently control anatomical structures, especially the thumb. Soft neoprene thumb straps that attach to a wrist band are enough to allow improved thumb control and grasping patterns that are developmentally appropriate. Also, elastomer or Adapt-It pellets can be used as a soft base for strapping for an infant or small child for soft control of a fisted hand or to maintain the palmar arches within a splint (Figure 18-10). The ThumbDuction strap is a soft prefabricated strap that is available in pediatric sizes from 3-Point Products (Figure 18-11). A volar wrist cock-up or ulnar gutter splint with an abduction thumb strap is a more rigid alternative if there is spasticity in the wrist. The combination of a rigid thumb “saddle” with a soft strap also helps position the thumb (Figure 18-12). In older, neurologically involved children, thumb control is more difficult, and thermoplastic splints are not as well tolerated if they have not been initiated when the child was younger and contractures less fixed.
FISTED HAND The fisted hand is difficult to distinguish in infants because the palmar grasp reflex is strong. This is easier to discern when looking at symmetry of the upper extremities. It may be appropriate to provide an antispasticity cone or soft cone if the hand does not open to explore or grasp in an age-appropriate pattern. Infant splints are tiny, and fabricating these miniature splints is an art in itself. It is perfectly fine to “cheat” and fabricate on the opposite hand and “flip” the splint, or look for a sibling or another similar-sized infant on which to fabricate the splint. In the older child the fisted hand can be a problem for function, as well as hygiene. The least restrictive splint is always the better choice; however, extra strapping or including proximal joints may be necessary for splint security and the prevention of splint distal migration. For younger toddlers and pre-school-aged children, weight bearing on their upper extremities requires wrist and finger extension. A clamshell or bivalved splint provides both wrist and hand control during weightbearing activity. Splint material plays a bigger part in this splint than in others. Flexor tone and fisting can immediately ruin a beautiful piece of soft Polyflex II by turning it into a squashed-up clump of material when applied to a sensitive or tactilely defensive hand. A more rigid splint material with more memory, such as
A B
Figure 18-10 A, Elastomer used as a splint base for a 2-month-old infant with fisted hand and thumb in palm. Strapping is made of neoprene and is run through slits in the material. (Splint courtesy KG Staines, Hand Care of Houston.) B, Adapt-It pellets used to form finger separation and control alignment within a resting splint.
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B
A
C
Figure 18-11 A, Fifteen-year-old child. with athetoid cerebral palsy demonstrating adducted thumb. B, ThumbDuction strap on child to improve resting posture. C, ThumbDuction strap used to stabilize thumb carpometacarpal joint while working on strengthening and manipulation activity.
Ezeform or Aquaplast, allows some touching of material to itself without instant bonding. The finished splint also has fewer fingerprints and rough edges. It also may be easier to use precooled Thera-Band or Ace wrap for a proximal “third hand” or to complete the proximal forearm shape and then reheat only the distal or hand part of the splint that will be shaped for the hand. This is a useful splint for supervised weightbearing activities. Because there is progression, the dorsal part of the splint can be used alone with individual finger strapping, which provides tactile and kinesthetic input through the palm. With spasticity in the upper extremities and hands, the position obtained with the antispasticity ball or cone helps reduce tone (Figure 18-13). In the most severe of hand contractures, in which the goal is to prevent skin breakdown and maintain hygiene, the Freedom Finger Contracture
Orthosis or “carrot,” may be used (Figure 18-14). There is now an inflatable version for progressive hand opening.
WRIST FLEXION The wrist is considered the “key” to the hand because the hand is dependent on the wrist for correct placement and stability to allow finger motion. It is crucial that the wrist be controlled to allow the fingers and thumb freedom. The optimal wrist position for finger function is 25 to 30 degrees of wrist extension. To allow maximum tactile input, dorsal splinting is preferred; however, pressure on a thin or bony wrist can become uncomfortable and cause skin breakdown. There are as many prefabricated and precut wrist splints as there are ideas for custom designs. If one splint
Splinting the Upper Extremity of a Child • 413
Figure 18-12 Thumb saddle splint with wrist strap used for thumb postioning and carpometacarpal stabilization. (Splint courtesy KG Staines, Hand Care of Houston.)
Figure 18-14 Fifteen-year-old child with variable flexor tone, demonstrating use of the finger contracture orthosis or “carrot” splint.
children, so learn to make a couple of types that suit your population (Figure 18-15). Prefabricated splints often are appropriate because they are time saving, which results in monetary savings as well.
WRIST U LNAR DEVIATION
Figure 18-13 Antispasticity ball splint with both dorsal and volar forearm. (Courtesy Sammons Preston Rolyan.)
design does not work after careful planning, then try another. This can be costly, but do not accept a splint that does not fit well or perform its intended function, no matter how long it took to make it. Neoprene also is effective if the problem is mild tone or hypotonicity. In an older child with strong or fixed contractures, it is not only painful, but useless to try to aggressively obtain wrist extension. More subtle measures such as static progressive splints or serial casting over a longer period of time are better choices. In general, the wrist cock-up splint is one of the most common upper extremity splints you will make on
An ulnar gutter splint allows ulnar control and a free palm and fingers for tactile input. As with other dorsal wrist splints, one must prepad the ulnar styloid to prevent pressure areas. This splint particularly may cause pressure at the ulnar styloid with pronation and supination if not properly fitted. Neoprene also is effective if the problem is mild tone or lack of tone, as with the wrist flexion problem. Severe ulnar deviation in an infant hinders hand-to-mouth exploration and selffeeding. In an older child it may limit the ability to hold a writing tool.
WRIST RADIAL DEVIATION Sometimes this is a problem in young infants with congenital anomalies. At times in radial “club” hand there are other problems in the forearm. Soft splinting of the infant, especially early on and during sleep, can help bring the wrist to neutral. With the older infant and toddler, a radially deviated wrist may not allow weight bearing and is problematic for holding food, toys, and writing instruments. Infants with milder cases may respond well with a long thumb spica splint that
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Figure 18-15 A, Wrist cock-up splint fabricated for post wrist trauma in a young girl. (Splint courtesy KG Staines, Hand Care of Houston.) B, Prefabricated “cozy” wrist splint, with washable terry cover. The wrist support and hand rest can be bent to fit.
is serially modified as wrist alignment improves. If there are severe bony anomalies, then splinting is less effective.
SUPINATION AND PRONATION Limited supination often affects the ability to self-feed and dress. This should be addressed early on. A soft thumb abduction supination splint (TASS) may be better tolerated than a traditional thermoplastic splint (Figure 18-16). Limited pronation often affects the ability to weight bear, write, and use a keyboard. The thumb abduction pronation splint (TAPS) also is a good gentle alternative.
WEIGHT BEARING ON THE U PPER EXTREMITIES Weight bearing on extended arms is a developmental milestone one looks for at 4 to 9 months of age because it helps develop hand prehension skills. It is usually not an issue in a young infant, but becomes more important when the child begins moving and propping on elbows in preparation to crawl. A single case study on the upper extremity muscle tone and function in a child with cerebral palsy indicates that after the application of an inhibitive weightbearing splint, tone changed minimally, fine motor functional task changes were variable, and arm-hand position improved. Subjective reports were given by family and other caregivers; they stated that tone decreased and function increased (Kinghorn & Roberts,
Figure 18-16 Thumb abduction supination splint demonstrated here to aid in play activity.
1996). This suggests that function can be affected by weight bearing. Similar splint designs have been discussed for wrist flexion and fisted hand problems in this chapter. (Figure 18-17).
I NDIVIDUAL FINGER CONTROL Older children learning to point or operate environmental controls or a keyboard may be dependent on isolated finger extension. Pointing, for key pad or keyboard selection, can mean a higher level of independence and control. A soft neoprene splint can be fabricated with mild tone, or the prefabricated finger
Splinting the Upper Extremity of a Child • 415
A B
C
Figure 18-17 A, Four-year-old with athetoid cerebral palsy, unable to weight bear on open palm. B, Splint fabricated to assist in supervised weight-bearing activities. Adapt-It pellets used to support the palmar arches while weight bearing. C, Child in side sitting with weight-bearing splint on right hand.
isolation glove with computer keyboarding also is a good option (Figures 18-18 and 18-19). Thermoplastic splinting may be more appropriate with greater tone. Writing instrument or pointing stick grasp can be assisted with splinting as well. For functional tasks such as writing or coloring, the child’s normal pattern of movement must be observed carefully because a splint can easily limit the child rather than promote function.
SPLINTING FOR I NFANTS IN THE N EONATAL I NTENSIVE CARE U NIT Splinting preterm and critically ill infants in the neonatal intensive care unit (NICU) requires its own special skills compared with the full-term infant not in the NICU. Hand dysfunction is seen frequently in this
population, and traditional therapeutic approaches may not be adequate to prevent progressive deformity in the hand of these critically ill infants. “Medical instability, time constraints, lack of family participation in the therapeutic program, the complexity of the treatment program, and fear of harming the infant are considerations that may indicate the need for splinting as an adjunctive therapeutic intervention. A number of factors are particularly important in making splints for infants, including splint alignment and padding, strap attachment, and thermoplastic malleability” (Anderson & Anderson, 1988).
Besides progressive deformities that cannot be handled solely by a hand treatment program, there are five other indications for use of splinting in infants with significant hand deformities (Anderson & Anderson,
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Figure 18-18 Index finger isolation splint in neoprene. (Courtesy Benik Corp.)
Figure 18-19 Example of index finger isolation splint designed to improve keyboard accuracy.
1988). First, the amount of time needed to perform an adequate hand treatment program may be too much for both staff and family in an NICU environment, because both the number of critical infants and the lifethreatening nature of their condition make hand therapy intervention lower on the priority scale in terms of time. Second, the critical, medically unstable infant will be stressed by increased handling and movement. The infant must use the caloric input for survival and then maturing and growing. Splinting provides positioning without as much handling. Third, because of possible unwillingness or inability by the family to participate in the infant’s rehabilitation due to factors such as grief, sibling and family issues, work schedule, and sometimes transportation issues, splinting should be initiated early. When establishing hand positioning and function from the start through early intervention, these family com-
plications will have less impact on the child. Fourth, the treatment program may be too difficult for the family or other staff to master. Interventions are determined by severity and most often the more severe the injury, the more time and mastery the intervention requires. Sometimes clinicians are not able to teach the complex interventions they have developed over years of practice to family or staff, even with the use of guided practice, pictures, and written instruction. Finally, fear can be the limiting factor for splinting. The infant who is critically ill and on many life-supporting and -monitoring machines is considered fragile; some family and staff have a difficult time performing adequate therapy. Splinting helps with positioning and adds the needed hours of corrective intervention that the upper extremities require. Static splinting or serial static splinting is likely to be most beneficial in the NICU. Weak muscles and joints may need protection and support to prevent further deformity, and may only be necessary for a short term if initiated early. The four most common splints used by the authors include the resting hand, palmar cone, wrist cock-up, and small finger antiabduction splints (Anderson & Anderson, 1988). During the first 4 hours of splinting, check the skin hourly for irritation and problems. Premature infants and sick neonates often have diminished fat pads and are more vulnerable to skin breakdown from pressure or force. After the first 4 hours, initiate a wearing schedule of 4 hours on and 1 hour off, keeping in mind that this is variable considering the severity and type of problem, as well as the infant’s reaction to the splint itself. Because of the small size of an infant’s extremity, contours and fit are important. Poor alignment or edge irregularities can produce severe problems quickly. Hand and arm exercises may be performed between splinting times with reassessment of the effectiveness of splinting to help determine modification to the therapy program. When choosing splint materials, keep in mind that low temperature materials that are easily remodeled are best. Remember that non-splint materials such as elastomer can be used for positioning and may be better tolerated. On the other hand, straps that are too thin or too tight can cause severe edema. Write “Not Tight” directly on the straps to help prevent family and staff from overtightening (Anderson & Anderson, 1988). Covering the entire splint with a sock or stockinette also protects the infant from pulling off the strap or splint and helps cushion the edges of the splint. Splinting in the NICU is challenging and rewarding. Attention to the needs of the critically ill infant and overall therapy program brings the greatest benefit to the infant. The team of physicians, therapists, parents and family, nurses, and other medical staff combines to
Splinting the Upper Extremity of a Child • 417 provide the best therapeutic interventions in this most complex situation.
for washing; the prefabricated 3-Point Products buddy straps are soft and conforming. It can be cut down in width for smaller hands.
SPLINTING FOR PEDIATRIC ORTHOPEDIC PROBLEMS
FLEXOR TENDON SPLINTING IN C HILDREN
Children generally recover much faster than adults from orthopedic problems, and are less affected by the amount of time spent immobilized. However, they are much more active both during the immobilization phase and after; therefore they often need protection from their own activity level.
FRACTURES Many nonoperative pediatric fractures are not even seen by therapists because the patients are doing well by the time they have their cast removal follow-up with the orthopedic physician. Postoperative fractures, on the other hand, may find their way to your clinic. Percutanous pins and external fixators can be protected by splinting circumferentially with bivalved or “clamshell” splinting. The zipper splint is an excellent “after cast” splint because it is circumferential and rigid (Figure 18-20). Buddy taping or buddy strapping usually is effective to encourage movement in a stiff finger after immobilization. Taping stays on better, but parents or caregivers should be instructed in how to apply it because it does get dirty. Buddy straps are more easily removed
Figure 18-20 Zipper splint used after–forearm fracture and postcast removal for support and protection.
Flexor tendon injuries in children are most commonly caused by sharp laceration (more than 50% from broken glass) and up to 25% of tendon injuries are missed (Osterman & Paksima, 2002). Controversy exists as to the type of repair, material to be used, period and type of immobilization, rehabilitation, use of tendon grafts, and primary versus delayed repair. Cunningham and co-workers (1985) reported on four cases in which flexor tendon lacerations were not repaired, with subsequent growth retardation of the injured fingers. They postulated that the growth disturbance was related to an absence of the mechanical force of flexion. The treatment of postoperative flexor tendon repairs in children is similar to the treatment in adults; however, there are special considerations for the pediatric population. Zone II flexor tendon repairs are the most complicated and controversial tendon repair for children because of multiple factors including the size of the tendons, pulley system and digital nerve involvement, age, and compliance with rehabilitation, and postoperative protocols. In chapter 119 of Rehabilitation of the Hand, the author states that the protocol for children younger than 8 years is cast immobilization from the humerus to the fingertips with the palm and fingers open for exercise (elbow at 90 degrees, wrist at 30 degrees of flexion, metacarpals at 70 to 80 degrees of flexion, and interphalangeal joints at 0 degrees) for 4 weeks. Children older than 8 years are treated postoperatively with the passive Duran program with parental instruction (Osterman & Paksima, 2002). The Duran program involves moving the joints and digits passively each hour either with the uninjured hand or by the parent. After 6 weeks of healing, the program follows the adult protocol. Children more than 10 years old (depending on maturity) may be candidates for the Kleinert protocol. This program uses rubber band traction attached to the digits to passively pull the digits into flexion so that the patient can actively extend the digits up to the top of the splint on an hourly basis. If using the traditional splinting procedures for the Kleinert or Duran procedures, it is necessary to use a dorsal blocking splint, which is applied from the proximal forearm to the finger tips and involves the injured fingers, as well as at least one border digit. However, in a child, including all the digits makes the program more tolerable. Tendon repair rehabilitation requires a high level of competence and should not be taken lightly. This is another area in which therapist and
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surgeon benefit from working as a team to promote the highest level of outcome possible.
J UVENILE ARTHRITIS As with adult onset arthritis, the patient with juvenile arthritis requires rest of inflamed joints and tissue. Although there are many classifications of juvenile arthritis, the joint problems and functional task problems are similar. Resting hand splints for night splinting to rest the joints in the functional position is a good preventive measure. Thumb carpometacarpal splints to support the thumb are practical to prevent fatigue if the hands are involved (Figure 18-21). Functional splints for handwriting and computer keyboarding use also are beneficial if the school-aged child will wear them in front of peers. For swan neck (Figure 18-22) and boutonnière (Figure 18-23) deformities, the same splint design as that used in adults can be employed. Proper alignment early on helps prevent joint contractures, which, when present, are more difficult to treat.
Figure 18-22 Prefabricated anti-swan neck splint. (Courtesy North Coast Medical.)
BRACHIAL PLEXUS I NJURY AND PERIPHERAL N ERVE I NJURY The treatment goals in brachial plexus injury and peripheral nerve injury vary significantly if there has been surgery to help balance musculature and regain function. One of the more common procedures for brachial plexus treatment in children is release of the subscapularis muscle. It may be released either at the origin at the inferior and anterior border of the scapula (subscapular fossa) or at the insertion on the lesser tubercle of the humerus. Releasing proximally or distally still requires the same splinting approach. The postoperative splint is fondly termed the “Statue of Liberty” splint because it horizontally abducts and externally rotates the shoulder, flexes the elbow, and
Figure 18-21 Static thumb carpal-metacarpal splint used to stabilize thumb for strengthening activity; may be used for handwriting activities as well.
Figure 18-23 Prefabricated anti-boutonnière splint. (Courtesy North Coast Medical.)
holds the wrist and forearm in neutral. Postoperative treatment protocols vary according to the surgeon’s procedure, technique, and preferences. Peripheral nerves can be damaged in a number of ways: (a) ischemia; (b) physical agents such as traction, laceration, pressure, stretching, cold, and heat; (c) infection and inflammatory processes; (d) ingestion of drugs or metals; (e) infiltration by pressure from tumors; and (f) the effects of systemic disease (Birch, Chir, & Achan, 2000). Nerve damage is extremely variable. Damage to part or an entire nerve can result from an open or closed injury, or it may be a healthy nerve with trauma or a more pathologic one with systemic illness. If there has been surgery, splints are designed around the postoperative protocols. Many times with children with peripheral nerve injury the “wait and see” rather than surgical exploration approach is taken if the nerve injury is a result of compression or stretch. In the “wait and see” period supportive splinting is recommended to maintain flexor and extensor balance to prevent contractures. Median nerve injury is the most commonly seen peripheral nerve injury in children resulting
Splinting the Upper Extremity of a Child • 419 from trauma (Birch et al., 2000). The radial nerve also is often affected because of the intimate proximity to the humerus. The case study at the end of this chapter discusses the splinting approach and progress of a radial nerve injury in a 4-year-old boy.
GENERAL CONSIDERATIONS IN PEDIATRIC HAND SPLINTING WEARING SCHEDULE FOR PEDIATRIC SPLINTS The wearing schedules for splints depend on the diagnosis and rationale for the splint. As with adult splinting, soft connective tissue responds better to low-load prolonged stress (LLPS) than high-load brief stress (HLBS). This has been documented time and again in scientific papers, as well as clinical research for exercise physiology and splint-wearing time (Austin & Jacobs, 2003; Gabriel, 1996; Hogan & Uditsky, 1998). Paul Brand was one of the first to apply this to splinting. He coined the term inevitability of gradualness. Dr. Brand was a physician and missionary who worked to make a difference in the quality of life of Indian children born with club feet that were never treated and were limited in mobility and social status by the time they became adults. In treating these infants, he allowed the child to nurse while seated in its mother’s lap as he gently pulled the foot toward normal alignment. If the infant looked up but continued sucking, that was where the foot was casted; if the baby stopped sucking and started to cry, they had gone too far. This type of serial casting was effective in remodeling soft tissue. Progress was maximized without tearing tissue and the results of the gentle but end-range stretching improved the outcome of many of these infants. Flowers and Michlovitz (1988) introduced the term total end range time (TERT) through further research in this same area of soft tissue adaptability. TERT is the frequency multiplied by the duration when at end range. This also has evolved with splinting to promote low-load prolonged stress. Three factors play a role in deciding wearing schedules: frequency, duration, and intensity of force. If the child initially wears the splint 20 minutes three times a day, the TERT is 60 minutes. If the intensity of force is too low there is no advancement in joint motion; however, it is necessary to allow the child and soft tissue to adapt and accommodate to the splint and the stretch it is providing. Slowly add to the wearing time by increasing both the frequency and duration. It must be compatible with the child’s and parents’ lifestyle and activities that are appropriate. The Appendix to this chapter includes a Splint Care Handout, which includes use, wear, and care instructions, as well as precautions and
patient education in both English (Appendix 18A) and Spanish (Appendix 18B). The older child or the parents of younger children also should demonstrate independent donning and doffing of the splint before leaving the clinic. Often, night splinting for positioning may be more beneficial. Applying the splint while the child is asleep may help to prevent resistance to splinting, as well as decrease mouthing and chewing on the splint.
COMPLICATIONS AND PRECAUTIONS Most complications of splinting concern vascularity and pressure. Symptoms of vascular insufficiency resulting from constriction or pressure include unrelieved pain, edema, blanching or discoloration, blistering, tingling or numbness, no pulse, and temperature change of the skin. Pericutaneus pins and wounds are precautions but not contraindications for splinting. Splints and straps should not put undue pressure on either pins or wounds. Careful monitoring by parents or the older child is important when pins or wounds are involved. Not only should a splint be easy to don, but also it must be difficult for the infant or young child to remove. Fondly termed anti-Houdini techniques have evolved with the need to keep children in their splint. Toni Thompson describes two types of Houdini children: Houdini Type I children remove the straps and slip out of the splint; Houdini Type II children slip out of the splint without removing any straps. Many of the techniques may already be familiar, but they are all worth mentioning (Box 18-3).
SUMMARY In conclusion, when splinting the child, remember to problem solve and prioritize the problems. The goals of splinting vary and may be intended to promote joint functional position or assist in holding an eating or writing utensil. One must keep in mind the normal configuration and architecture of the hand whether to prevent contractures or help restore soft tissue length after an injury. A well-designed splint should provide the needed support or restriction without interfering with normal exploration and movement patterns. Children who have not experienced normal movement patterns with grasp, release, or weight bearing may gain new information from their environment with the use of splints; however, sometimes the right answer is no splint. Splinting is a science, as well as an art. Once mastered, splinting is a great instrument to have in your therapy toolbox when treating children. Enjoy the journey.
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BOX 18-3
Anti-Houdini Techniques
TYPE I: HOUDINIS WHO REMOVE THE STRAPS AND SLIP OUT OF THE SPLINT Figure 18-24, A: Wrap self-adhesive bandage (e.g., Coban) around the straps or entire forearm. Figure 18-24, B: Wrap a 2′ length of 1/4 ″ loop Velcro around the forearm and weave it under the overlapping loops. When removal is attempted, it just tightens. Figure 18-24, C: Use a square metal ring or plastic D-ring applied with sticky back Velcro to the proximal end of the splint. Run the tail end of the Velcro through it. When removal is attempted, the tail end will not lift up. Figure 18-24, D: Cut each strap 1″ longer than is needed and Velcro together with sticky back hook tab that has been made from doubling a piece of sticky back hook on itself. Figure 18-24, E: Make holes along the border of the splint and use a regular or curly shoestring to tie the splint on. Toddler shoestring holders can hold these ties away from prying fingers and mouths. Also, the strap is slipped through a slot that has been placed near the edge of the splint, making strap removal difficult. Figure 18-24, F,G: Permanently attach one end of the strap with a rivet or custom rivet using splint material.
Figure 18-24, H: An additional strap can be placed over the forearm strap that attached to itself and will only spin around the forearm, but needs to be removed to take off other straps. Figure 18-24, I: Covering the entire splint with a tube sock or stockinette will make the straps more difficult to reach. TYPE II: HOUDINIS WHO SLIP OUT OF THE SPLINT WITHOUT REMOVING ANY STRAPS • Make sure borders of the splint are only one half of the forearm thickness so that straps have the top of the forearm to hold onto. • Increase the curve or extension at the wrist as much as tolerable for the goal of the splint design, as straighter designs are easier to slip off. • Figure 18-24, J: Fasten padding to the underside of the straps to add friction to removal of the splint. • Figure 18-2: More proximal joints may be immobilized for securing the splint as well, even for a short period while the child gets used to having the splint on. • Mark Willey has also modified the typical thumb loop splint by sewing on a click buckle clasp at the wrist. • Figures 18-24, K, 18-25, 18-26: Do not forget the appeal of the splint color or decoration. Fabricating a splint on the child’s stuffed animal or doll can also encourage positive results.
A
B
C
Figure 18-24 A–K, Anti-Houdini splinting. (See box 18-3 for legends.)
Splinting the Upper Extremity of a Child • 421
E
D
G
F
H
Figure 18-24, cont’d
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I J
K
Figure 18-24, cont’d
Figure 18-25 Dorsal blocking splint designed to bring a smile to a child’s face and improve wearing compliance.
Figure 18-26 Splinting can be fun and creative. (Splint courtesy KG Staines, Hand Care of Houston.)
Splinting the Upper Extremity of a Child • 423
CASE STUDY A C HILD WITH RADIAL N ERVE PALSY Carlos is an active 4-year-old child who fell off the monkey bars and sustained a Type III complete, displaced left supracondylar humerus fracture. The fracture was closed reduced and fixed with two K-wires under C-arm guidance by an orthopedic surgeon the next day. Progressive high radial nerve palsy was apparent when the cast was removed at 4 weeks postoperatively. Carlos was referred to therapy 3 months later. Initially he had no active wrist extension and when digital extension was attempted the unopposed long flexors created a “claw” deformity (Figure 18-27). He was not using the extremity to play, feed, or dress himself. The radial nerve splint was fabricated to hold the wrist in extension and balance the wrist and digital extensors with the strong flexors and still allow full finger flexion and grasp, as well as sensory and tactile input through the palm (Figure 18-28). This is a dorsal splint fabricated with 3/32″ Polyflex II. The finger
Figure 18-27 Demonstrates maximum effort for wrist and finger extension.
B A
C
Figure 18-28 A, Volar view of radial nerve splint using Thera-tubing for digital support. B, Dorsal view of radial nerve splint. C, Maximum extension effort with splint on. D, Maximum flexion effort with splint on.
D
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A B
Figure 18-29
A, Night splint decorated by patient. B, Night splint applied.
loops are made with a continuous loop of Thera-tubing in the light yellow strength. The holes in the splint were made with a Dremel tool with a round rotary blade. Carlos’ mother was instructed in donning and doffing the splint, as well as a daytime wearing schedule and in recognizing problems with the splint. A resting hand night splint also was fabricated because his mother stated his hand stayed “fisted” at night (Figure 18-29). On his next visit approximately 2 weeks later his wrist and fingers appeared more balanced, with trace muscle activity noted in the long extensors of the left wrist and
digits (Figure 18-30). After approximately 2 more weeks, his mother reported that Carlos had started holding light objects in his left hand for play. At the 6-week visit the wrist extensors were at a fair grade and some clawing was still visible with wrist extension with effort (Figure 18-31). At the final visit (20 weeks postoperative), Carlos was able to use his left hand and wrist with full function, and the radial nerve splint was discontinued (Figures 18-32 to 18-34). The night splint was advised to be worn for another 2 weeks, and thereafter only if Carlos was observed fisting at night because of fatigue or overexertion.
Figure 18-31 After-visit demonstrating maximum effort for wrist and finger extension. The patient continues to improve wrist and finger control and uses the hand for light play and activity. Figure 18-30 Second visit demonstrates maximum effort for wrist and finger extension, improved muscle balance, and less clawing.
Splinting the Upper Extremity of a Child • 425
Figure 18-33 Final visit demonstrates normal control with finger flexion and grip. Figure 18-32 Final visit demonstrates good control of wrist and finger extension.
Figure 18-34 Final visit demonstrates functional use of hand for favorite activity with Yu-gi-oh cards.
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ACKNOWLEDGMENTS Special thanks to Otto, Eric, Karl, Stefan, mom and dad, Gloria Gogola, Trent Carlyle, Kimberly Staines, Jean Polichino, Karen Lahvis, and the girls. Also, the Spanish version of Appendix 18B is courtesy of A. Galindo.
REFERENCES Anderson L, Anderson J (1988). Hand splinting for infants in the intensive care and special care nurseries. American Journal of Occupational Therapy, 42(4):222–226. Austin N, Jacobs M (2003) Splinting the hand and upper extremity: Principles and process. Philadelphia, Lippincott Williams & Wilkins. Birch R, Chir F, Achan P (2000). Peripheral nerve repairs and their results in children. Hand Clinics, 16(4):579–595. Brand P (2002). The forces of dynamic splinting: Ten questions before applying a dynamic splint to the hand. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1811–1817). St Louis, Mosby. Byron P (2002). Splinting the hand of a child. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1914–1919). St Louis, Mosby. Cunningham MW, Yousif NJ, Matloub HS, et al. (1985). Retardation of finger growth after injury to the flexor tendons. Journal of Hand Surgery, 10:115–117. Fess EE (2002a). A history of splinting: To understand the present, view the past. Journal of Hand Therapy, 15:97–132. Fess EE (2002b). Principles and methods of splinting for mobilization of joints. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1818–1827). St Louis, Mosby. Fess EE, Gettle K, Philips C, Janson J (2005). Hand and upper extremity splinting: Principles & methods, 3rd ed. St Louis, Mosby. Flowers KR, Michlovitz SL (1988). Assessment and management of loss of motion in orthopedic dysfunction. In Postgraduate advances in physical therapy (pp 1-11). Alexandria, VA: American Physical Therapy Association. Gabriel L (1996). Splinting children who have developmental disabilities. In B Coppard, H Lohman, editors: Introduction to splinting: A critical thinking and problem-solving approach. St. Louis, Mosby. Hogan L, Uditsky T, (1998) editors: Pediatric splinting: Selection, fabrication, and clinical application of upper extremity splints. San Antonio, TX, Therapy Skill Builders. Kinghorn J, Roberts G (1996).The effect of an inhibitive weight-bearing splint on tone and function: A single-case study. American Journal of Occupational Therapy, 50(10):807–815. Osterman L, Paksima N (2002). Flexor tendon injuries and repair in children. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1907–1913). St Louis, Mosby.
Thompson T (2004). Strategies and techniques to enhance wearing compliance of splints in pediatrics. Advance for Occupational Therapy Practitioners, 17:14–15. Van Straten O, Sagi A (2000). “Supersplint”: A new dynamic combination splint for the burned hand. Journal of Burn Care & Rehabilitation, 21(1):71–73.
SUGGESTED READING Barnes KJ (1986). Improving prehension skills of children with cerebral palsy: A clinical study. Occupational Therapy Journal of Research, 6(4):227–239. Bell-Krotoski J (2002). Plaster cylinder casting for contractures of the interphalangeal joints. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1839–1845). St Louis, Mosby. Brand P (1985) Clinical mechanics of the hand. St Louis, Mosby. Brand P (2002) Lessons from hot feet: A note on tissue remodeling (1944), Correspondence from Dr. Brand to Elaine Ewing Fess, MS, OTR, FAOTA, CHT about soft tissue remodeling process. Journal of Hand Therapy: Splinting Special Issue, 15:133–135. Colditz J (2002) Anatomic considerations for splinting the thumb. In J Hunter, E Mackin, A Callahan, T Skirven, L Schneider, L Osterman, editors: Rehabilitation of the hand and upper extremity (pp. 1858–1874). St Louis, Mosby. Colditz J (2002). Plaster of Paris: The forgotten hand splinting material. Journal of Hand Therapy, 15(2):144–157. Exner CE, Bonder BR (1983). Comparative effects of three hand splints on bilateral hand use, grasp, and arm-hand posture in hemiplegic children: A pilot study. The Occupational Therapy Journal of Research, 3:75–92. Fitoussi F, Mazda K, et al. (2000). Repair of the flexor pollicis longus tendon in children. The Journal of Bone & Joint Surgery, 82(8):1177–1180. Glasgow C, Wilton J, Tooth L (2003). Optimal daily total end range time for resolution in hand splinting. Journal of Hand Therapy, 16(3):207–218. Greenhalgh D (2000). Management of acute burn injuries of the upper extremity in the pediatric population. Hand Clinics, 16(2):175–186. Keren O, Shnarch-Voda M, Barak D, Behroozi K (2003). A therapeutic splint for hypertonic flexed elbow in upper motor neuron diseased patients. Prosthetics and Orthotics International, 27:63–68. Lee M, LaStayo P, vonKersburg A (2003). A supination splint worn distal to the elbow: A radiographic, electromyographic, and retrospective report. Journal of Hand Therapy, 16:190–198. Lin SC, Huang TH, Lin CJ, Hsu HY, Chiu HY (1999). A simple splinting method for correction of supple congenital clasped thumbs in infants. Journal of Hand Surgery (Br) 24(5):612 –614. Lohman M (2001) Antispasticity splinting. In B Coppard, H Lohman, editors: Introduction to splinting: A criticalthinking & problem-solving approach (pp. 326–349). St Louis, Mosby. MacKinnon J, Sanderson E, Buchanan J (1975). The MacKinnon splinting: A functional hand splint. Canadian Journal of Occupational Therapy, 42(4):157–158.
Splinting the Upper Extremity of a Child • 427 Malik M (1985). Manual on static hand splinting. Pittsburgh, AREN. Press J, Wiesner S (1990). Prevention: Conditioning and orthotics. Hand Injuries in Sports and Performing Arts, 6(3):383–392. Schultz-Johnson K (2002). Static progressive splinting. Journal of Hand Therapy, 15(2):163–178. Shah M, Lopez J, et al. (2002). Dynamic splinting of forearm rotational contracture after distal radius fracture. Journal of Hand Surgery, 27A:456–463. Sheridan R, Baryza M, Pessina M, et al. (1999). Acute hand burns in children: Management and long-term outcome based on a 10-year experience with 698 injured hands. Annals of Surgery, 229(4):558–556.
Tomaino M (2001). Ligament reconstruction tendon interposition arthroplasty for basal joint arthritis. Hand Clinics, 17(2):207–221. Willey M (2004). Modification to a pediatric thumb splint. American Journal of Hand Therapy, 17(3):379–380. Wilton J (2003). Casting, splinting, and physical and occupational therapy of hand deformity and dysfunction in cerebral palsy. Hand Clinics, 19:573–584. Wu S (1991). A belly gutter splint for proximal interphalangeal joint flexion contracture. American Journal of Occupational Therapy, 45(9):839–843.
Appendix
18A
SPLINT INSTRUCTIONS
Name________________________________________________ Splint type_______________________
Date__________________ Goal of splint______________________
CARE OF YOUR SPLINT 1. Your splint is fabricated from heat-sensitive material. a. Heat will melt your splint. b. Do not leave your splint in or near a heat source. c. Do not leave your splint in your car or truck. 2. Cleaning: a. Clean with lukewarm water and soap unless padded. b. Rubbing alcohol removes most ink and newsprint. 3. Cleaning the stockinette and straps: a. Wash by hand or in a mesh bag in the machine. b. Let them air dry. Do not put in dryer. c. Trim ends of stockinette when they fray. CARE OF YOUR SKIN 1. Stockinette is to help reduce irritation from the plastic, as well as to reduce the sweatiness underneath the splint. A tube sock with the toe-end cutoff makes a good substitute. 2. Corn starch or light powder is recommended for excessive perspiration. 3. 20-Minute rule: If your skin remains red for more than 20 minutes after removing the splint it indicates too much pressure from the splint. Please notify your therapist to schedule splint modification. 4. Problems with your splint that require immediate adjustment. Significant swelling, color, or temperature change, skin irritation, increase in tingling, or numbness. WEARING SCHEDULE ____ As needed for ADL, sports, leisure, or work activity ____ Day time _______times per day for _______minutes; increase to _____________ ____ Night only ____ Full time except hygiene ____ Do not remove The above instructions have been explained to me and I understand the use, wear, care, and precautions about my splint.
______________________________ Patient or Parent (if under 18)
____________________________ Therapist
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Appendix
18B
CUIDADO DE LA FÉRULA
Nombre ______________________
Dato ________________
Férula ______________________
Las siguientes instrucciones se deben de aplicar para el cuidado y limpieza de su férula. LIMPIEZA 1. Plástico (férula) a. Limpie la férula con una toalla o esponja usando agua fria y jabón. b. Limpie la férula con alcohol para quitar tinta o manchas de periódico. c. Para manchas más difíciles use un detergente, por ejemplo, Lysol. Enjuague la férula muy bien antes de ponérsela porque los químicos pueden irritar la piel. 2. Cintas de Velcro a. Las cintas de Velcro se pueden lavar a mano o en la lavadora. 3. Telas a. Lave a mano o remoje en jabón de lavar. b. También se pueden poner dentro una funda o bolsa de lavandería y lavar en la lavadora. EVITE CALOR 1. La férula esta fabricada de un material que reacciona a lo caliente. Demasiado calor puede cambiar la forma o deretir la férula. a. No deje la férula cerca de objetos calientes. b. No deje la férula cerca de una ventana donde le pueda dar el sol. c. No deje la férula en un carro (automóvil) especialmente durante los meses de verano. CUIDADO DE LA PIEL 1. Debe de usar la tela para comodidad y protección contra irritación de la férula (plástico). 2. En caso de mucho sudor, use harina de maíz (maizena) para mantener la piel seca. Pongase la harina de maíz directamente en la mano o brazo antes de ponerse la tela. También la puede poner la maizena directamente en la férula. 3. Observe la piel para sitios (partes) rojos al quitarse la férula. Sitios (partes) rojos que no se desaparecen en 15–20 minutos indican puntos de presión. Debe de llamar y hacer una cita con la terapista para que le modifiquen la férula. Si tiene algún problema o alguna pregunta acerca de la férula, favor de llamar a su terapista. _____ Duracion (uso) ____________________________________________________ _____ Dia ______________________________________________________________ _____ Noche ____________________________________________________________ _____ Tiempo completo excepto al banarse ____________________________________
Firma _____________________________________
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Terapista _______________________________________
Appendix
18C
LIST OF VENDORS
1. Alimed Inc. 297 High Street Dedham, MA 02026-9135 (800) 225-2610 www.alimed.com
5. North Coast Medical 18305 Sutter Boulevard Morgan Hill, CA 95037-2845 (800) 821-9319 www.ncmedical.com
2. Benik Corporation 11871 Silverdale Way NW #107 Silverdale, WA 98383 (800) 442-8910 www.benik.com
6. Sammons Preston Rolyan 4 Sammons Court Bolingbrook, IL 60440-4995 (800) 323-5547 www.sammonsprestonrolyan.com
3. DeRoyal/LMB 200 DeBusk Lane Powell, TN 37849 (800) 541-3992 www.deroyal.com
7. 3-Point Products 1610 Pincay Court Annapolis, MD 21401 (888) 378-7763 www.3pointproducts.com
4. Joe Cool Company 9448 Lady Dove Lane South Jordan, UT 84095 (800) 233-3556 www.joecoolco.com
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19
EFFICACY OF INTERVENTIONS TO ENHANCE HAND FUNCTION Jane Case-Smith
CHAPTER OUTLINE
LEVELS OF RESEARCH EVIDENCE
LEVELS OF RESEARCH EVIDENCE
The studies described in this chapter are categorized according to their level of research evidence to assist the reader in interpreting the importance of the findings. Phillips and co-workers (1998) have categorized research designs into five levels of research evidence (Table 19-1). These categories have been adopted by professional organizations that have synthesized research reports into summaries of research evidence (Butler & Darrah, 2001; Law, 2002). The levels of research evidence define the confidence that professionals can place in a study’s findings to be valid or true. Randomized clinical trials (RCTs) are categorized as Level I research evidence and have high rigor and validity. When a Level I study produces positive effects, it provides strong evidence that an intervention is effective. Randomization increases the probability that samples are equal at the beginning of the trial, and therefore, provide confidence that if the samples differ after intervention, change is related to the intervention. RCTs also use “blinding” when testing, which means that both the researchers and the subjects are “blind” as to whether the subject is in the experimental or the control group. Blinding is not always possible in OT intervention, because, of necessity, the subjects know that they are in the experimental group. In Level II research, an experimental group is compared with a control or comparison group, but a convenience sample rather than randomized sample is used. As a result, it cannot be assumed that the samples are equal and the results can be influenced by initial differences in the samples. One way to improve nonrandomized sampling is to use matched samples, ensuring that the groups are equivalent for certain characteristics. Small samples may be more equivalent if matched
CHILDREN WITH CEREBRAL PALSY Weight Bearing on Hands Neurodevelopmental Treatment Casting and Splinting Constraint-Induced Movement Therapy Surgical and Medical Intervention CHILDREN WITH DEVELOPMENTAL COORDINATION DISORDER OR MILD DISABILITIES Cognitive Orientation to Daily Occupational Performance Occupational Therapy Approaches with Preschool Children INTERVENTIONS TO IMPROVE HANDWRITING Instructional Approaches Occupational Therapy Approaches SUMMARY
Occupational therapists have assumed leadership roles in developing interventions to enhance children’s fine motor skills. As leaders in the development of practice models and strategies to improve hand function, occupational therapists also have researched the effectiveness of these interventions on children’s function. This chapter describes occupational therapy (OT) and other discipline research that has examined hand function intervention outcomes and synthesizes current knowledge on the effectiveness of these interventions.
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Table 19-1
Levels of research evidence
Level of Research Evidence
Types of Research Design
I
Randomized controlled trials Randomized crossover designs True experimental design
II
Nonrandomized controlled trial Prospective cohort study with control group Quasi-experimental designs. May include single subject when multiple baseline and ABABA (alternating intervention and baseline)
III
Cohort study with historical control group Single subject ABA design
IV
Before and after case series without control group Descriptive case series or case reports Pre-experimental designs.
V
Expert opinion
Theories based on basic science. Adapted from Butler and Darrah (2001), Law (2002), and Phillips and co-workers (1998).
rather than randomized. Level II studies provide fair confidence in the validity of the findings, particularly if the sample size is large. Level III studies refer to cohort studies that compare existing patient groups who do or do not receive the intervention. It also includes single subject designs in which subjects are tested during baseline, intervention and return to baseline or when subjects receive a series of alternating interventions and are repeatedly measured during the treatment phases. An important aspect of these studies is that the subjects are evaluated on a repeated basis for an extended time frame and they serve as their own control (are measured when not receiving intervention). Level III studies also include case control studies in which subjects are matched by their outcomes. This type of study was not included in the review of hand function interventions. Level IV studies are case series studies in which only one group (cohort) of subjects, all of whom receive the intervention, are assessed. A control or comparison group is not used. This level includes case studies. These studies provide weak evidence, and minimal confidence in the findings. Level V research evidence refers to expert opinion, and is associated with low confidence in the results. Level V evidence is not discussed in this chapter.
The first section of this chapter describes interventions for children with cerebral palsy (CP) who had moderate to severe hand function limitations. The second section describes interventions for children with developmental coordination disorder and milder hand function limitations. The third section describes research of handwriting interventions. A summary discusses issues in research of hand skill interventions and future directions for research.
CHILDREN WITH CEREBRAL PALSY CP is a nonprogressive posture and movement disorder that results from a brain lesion around the time of birth. CP is a common disorder (2 in 1000) (Behrman, Kleigman, & Jenson, 2000), and its clinical picture varies greatly. Lifelong medical and functional problems are associated with cerebral palsy and are well described in Chapter 16. Most individuals with CP have problems in hand function, characterized by weakness, spasticity, incomplete isolation of finger movements, and sensory impairments (Duff & Gordon, 2003). Bly (1983) explained that in children with CP,
Efficacy of Interventions to Enhance Hand Function • 435 movements often are primitive, asymmetric, and stereotypical patterns of flexion and extension. These movement problems create functional performance difficulties across most life skills. A number of intervention methods have been applied to remediate the motor problems associated with CP (Table 19-2). Several approaches (e.g., neurodevelopmental treatment [NDT]) were developed specifically for children and adults with CP. Other approaches (e.g., constraint-induced therapy) were developed for other impairments and have been applied to the problem of CP. The research of interventions to manage and improve function in children with CP is equivocal and has not produced consensus on best practice. This section reviews studies of weight bearing on hands, neurodevelopmental treatment, and constraint-induced movement therapy designed to improve hand function in children with CP. It also reviews studies on splinting and casting of the upper extremity and specific medical and surgical approaches used to improve arm and hand function.
WEIGHT BEARING ON HANDS Weight bearing on hands in individuals with CP is believed to improve hypertonicity and active range of motion. Barnes (1989a,b) implemented two multiplebaseline single subject design studies to examine the effect of weight bearing on extended arms to the development of prehension skills. Each study investigated three children with spastic CP who participated in weight-bearing exercises. In the first study, Barnes (1989a) implemented 8 weeks (about 19 to 20 sessions) of weight-bearing intervention with three boys (ages 4 to 6 years). Components of grasp, release, and reach were measured during baseline and intervention. These components were based on Erhardt’s hand development assessment. All three boys made significant improvement, although not always in both arms. In the detailed analysis of graphed data, extensor movements (i.e., release) appeared to improve more than grasp for subject 1. In a second study, Barnes (1989b) replicated these findings. Her second study also used three boys with spastic CP, who were slightly older (5 years 9 months to 7 years 5 months). Using a multiple baseline design, intervention comprised four sessions of weight-bearing activities per week for about 10 weeks. After the intervention, two subjects demonstrated clear improvement in prehension and one did not. A suggested reason for the lack of improvement in one boy was difficulty in implementing the procedure because of bilateral elbow contractures. These studies demonstrated the positive effects of weight bearing on hands. Limitations of the studies included use of AB single subject design (Level IV
evidence) and a nonstandardized measure that required some judgment as to what was observed. In a study similar to Barnes, Chakerian and Larson (1993) investigated the effects of upper extremity weight-bearing on hand opening and prehension patterns. A 10-week design with baseline, 2 to 5 weeks of treatment, and a period of no treatment (Level III evidence) was used with 10 children with spastic cerebral palsy. The treatment consisted of upper extremity weight bearing activities. Treatment effects were measured through analyzing components of reach, grasp, and release using videotapes of the children’s performance. In addition, the weight-bearing surface of the hand was measured by tracing around the hand and calculating the area of weight-bearing surface. Developmental level of grasp and release were measured using a method similar to Barnes (1989a,b). Hand surface area increased significantly from baseline to intervention, indicating more complete weight bearing and greater extension of elbow, wrist, and fingers. Grasp and release improved overall but improvements week to week were not significant. Reach did not improve with weight bearing; no difference was found in the path of the hand toward the object (reach was not more direct or in active supination). They did observe increased elbow, wrist, and finger extension, similar to the findings of Barnes. In 1996, Kinghorn and Roberts used a single subject design to investigate the effects of weight bearing on decreasing upper extremity spasticity in a 20month-old boy. They theorized that weight bearing on hands decreases spasticity by inhibiting motor neuron excitability and stretching connective tissues. They were directly interested in increasing the hand’s weight-bearing surface as evidence of increased range of motion (ROM) and decreased finger flexor spasticity. Kinghorn and Roberts designed a weight-bearing splint similar to that of Smelt (1989), who reported a case study of a 17-month-old boy with left spastic hemiparesis using an inhibitive weight-bearing splint. This splint allows contact of maximal palmar surface when fingers have flexion contractures. Kinghorn and Roberts used an ABA design over 24 weeks, eight baseline, eight weight-bearing, and eight second baseline. The hand weight-bearing area did not change with the treatment, arm position changed slightly, and functional activities did not improve. These results contradicted Smelt, who found improvement in ROM, weight-bearing surface of the hand, and function. In summary, Level III and IV studies with small samples have been used to examine the effects of weight bearing on hands. The hypothesized effect of weight-bearing activities is decreased hypertonicity, increased tendon length, improved ROM, and by exten-
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Table 19-2
Research studies examining the efficacy of interventions to enhance hand function in children with cerebral palsy (1985–2005)
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Barnes (1989a)
Level IV AB single subject
N=3 spastic cerebral palsy (CP) 4–6 years
Weight bearing on extended arms; 19–20 sessions
Erhardt’s assessment of prehension
Visual analysis. Prehension skills improved in two subjects.
Barnes (1989b)
Level IV AB single subject
N=3 spastic CP 5.9–7.5 years
Weight bearing on extended arms; 4 sessions/wk for 10 wk
Erhardt’s assessment of prehension
Visual analysis; two of three improved
Chakerian & Larson (1993)
Level III ABA cohort design
N = 10, spastic CP
Upper extremity weightbearing; 10 weeks with 2- to 5-week treatment
Videotape of reach, grasp, release. Hand weight-bearing surface area
Hand surface increased. Reach did not improve. Grasp and release improved.
Kinghorn & Roberts (1996)
Level IV ABA single subject
N = 1, spastic quadriplegia CP
Use of a weight-bearing splint; 8 wk baseline, 8 wk treatment, 8 wk baseline
Hand weightbearing surface area; arms position; two play activities
Hand surface area and play activities did not improve. Arm position did improve.
Lilly & Powell (1990)
Level IV ABAB
N=2 spastic diplegia 27, 32 months
Alternating play and neurodevelopmental treatment (NDT); 12 wk, six sessions of NDT and six of play
Analysis of dressing in shirt, socks, jackets
No difference between play and NDT effects
DeGangi (1994)
Level IV case study
N = 3, one spastic diplegia, one spastic quadriplegia, one hemiparesis
Individualized NDT techniques, 2/wk for 8 wks
For child with hemiparesis: Posture, use of right hand, and bilateral and visual motor skills
Substantial gains in all skill areas
Fetters & Kluzik (1996)
Level III multiple crossover
N = 8, spastic quadriplegia 10–15 years
NDT for 35 minutes for 5 days and practice for 5 days.
Upper extremity movement using kinematic analysis
Changes were not significant for NDT alone; were significant for treatments combined.
Efficacy of Interventions to Enhance Hand Function • 437
Table 19-2
Research studies examining the efficacy of interventions to enhance hand function in children with cerebral palsy (1985–2005)—cont’d Level of Evidence
Sample
Intervention
Measures
Findings
Law et al. (1991)
Level I randomized clinical trial
79 children with spastic CP
Intensive and regular NDT with casting, intensive and regular NDT alone for 6 months
PDMS-FM QUEST ROM of wrist
PDMS: not significant; QUEST, more improved for children who wore casts
Law et al. (1997)
Level I crossover with washout
N = 50 spastic CP, with moderatesevere UE impairment, 18 months– 4 years
Intensive NDT with casting and regular occupational therapy; 4 mo, 2 mo washout, 4 mo
PDMS-FM QUEST
No difference among treatment types
Cruickshank & O’Neill (1990)
Level IV case study
N = 1, spastic quadriparesis, 11 years
Plaster cast, then fiberglass cast with splint
Range of motion (ROM)
ROM increased with plaster cast and decreased with fiberglass cast.
Copley, WatsonWill, & Dent (1996)
Level IV cohort study, pre- and postmeasures
N = 11, hemiplegic and quadriplegic CP, 5–18 years
Plaster cast for 4–6 weeks, followed by post casting program
ROM, muscle tone, progress on goals
ROM increased and muscle tone decreased immediately after casting. At 6-month follow-up; ROM maintained; some hand function goals achieved.
Tona & Schneck (1993)
Level IV ABA
N = 1; CP, age = 8 years
Plaster cast applied; study for 11 days, cast worn for 48 hours
Functional activities; modified Ashworth Scale; resistive movement
Reduced spasticity immediately, but not long term.
Goodman & Bazyk (1991)
Level IV single subject AB
N = 1. moderate spastic quadriparesis, age = 4 years
Child wore a short opponens splint, 6 h/day for 4 weeks
ROM, grip strength, dexterity, and prehension patterns
ROM, dexterity, quality of movement improved; strength did not.
Authors
Continued
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Table 19-2
Research studies examining the efficacy of interventions to enhance hand function in children with cerebral palsy (1985–2005)—cont’d
Authors
Level of Evidence
Reid & Sochaniwskyj (1992).
Sample
Intervention
Measures
Findings
Level II alternative treatments
N = 10, children with CP with upper extremity involvement
Children wore a hand position splint
Quality of movement in reaching, movement latency, time, average velocity, and movement units
No significant differences with or without the splint
Crocker, MacKayLyons, & McDonnell (1997)
Level III ABA
N = 2, hemiparesis; ages = 2 and 3 years
Constraint-induced (CI) therapy, wore a splint for 3 weeks, 2 weeks before and after were baseline, with 6-month follow-up
Analysis of play session for how often children used involved hand
Use of involved hand doubled. Improvements in grasp, release, and sensory exploration were significant.
Charles, Lavinder, & Gordon (2001)
Level IV AB design
N = 3, hemiparesis CP
CI therapy, wore a sling 6 h/day for 14 days
Manual dexterity, strength sensory discrimination, bilateral coordination
Hand function improved in 2 or 3 children; sensory discrimination improved in all; coordination of force improved in 1.
DeLuca, Echols, Ramey, & Taub (2003)
Level IV case study
N = 1, hemiparesis CP, age = 15 mo
CI therapy, wore a bivalved cast for 2 weeks
PDMS-FM, DDST, Pediatric Motor Activity Log, Toddler Arm Use Test
All scores improved significantly and used involved arm 100% in free play.
Pierce, Daly, Gallagher, Gershkoff, & Schaumburg (2002)
Level IV case study
N = 1, hemiparesis CP, age = 12 years
CI therapy, plus 62-hour sessions of OT/PT
Wolf Motor Function Test, Assessment of Motor and Process Skill (AMPS); 8-month follow-up
Scores improved for the Wolf Motor Function Test, AMPS, and increased use of involved arm by selfreport.
Efficacy of Interventions to Enhance Hand Function • 439
Table 19-2
Research studies examining the efficacy of interventions to enhance hand function in children with cerebral palsy (1985–2005)—cont’d
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Willis, Morello, Davie, Rice, & Bennett (2002)
Level I randomized clinical trial; crossover design
N = 25, hemiparesis CP, ages = 1–8 years
CI therapy, cast was worn for 1 month, measured at 6 months, then crossover
PDMS-FM, parent report
PDMS-FM improved significantly, more in CI group than control group; 21 of 22 parents reported improvement at follow-up
Taub, Ramey, DeLuca, & Echols (2004)
Level I randomized clinical trial
N = 18, hemiparesis CP, ages = 7 mo to 8 yrs
CI therapy; children wore bivalved casts and received 6 hours of therapy for 21 days or conventional therapy.
Pediatric motor activity level (PMAL) Toddler Arm Use Test (TAUT)
Large gains with CI therapy, TAUT and PMAL improved significantly. Gains were maintained at 3- and 6months follow-up.
Dudgeon, Libby, McLaughlin, Hays, Bjornson, & Roberts (1994)
Level IV pre- and postintervention with follow-up
N = 29, spastic CP
Selective dorsal rhizotomy with postoperative physical and occupational therapy
Pediatric Evaluation of Disability Inventory (PEDI); reach and coordination, 6- and 12month follow-up
Children with diplegia improved in functional mobility and self-care on the PEDI. Did not improve in reach and coordination.
Loewen, Steinbok, Holsti, & MacKay (1998)
Level IV, pre- and post-surgery with follow-up
N = 37, spastic CP; age mean = 4.1 yrs
Selective dorsal rhizotomy
Quality of Upper Extremity Skills Test (QUEST), WeeFIM, 1 year after surgery
Significant gains on both scales
Mittal, Farmer, Al-Atassi, et al. (2002a)
Level IV pre- and post-surgery with 3 and 5 year follow-up
N = 57, 41 at 3 years, and 30 at 5 years, spastic CP, 3–5 years
Selective dorsal rhizotomy
PEDI
Self-care and mobility increased significantly at 3 and maintained at 5 years. Continued
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Table 19-2
Research studies examining the efficacy of interventions to enhance hand function in children with cerebral palsy (1985–2005)—cont’d
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Mittal, Farmer, Al-Atassi, et al. (2002b)
Level IV pre- and post-surgery with follow-up
N = 70 at post-op, 45 at 3 years and 25 at 5 years; spastic CP, 3 to 7.4 years at the time of surgery
Selective dorsal rhizotomy
PDMS-FM
Significant gains at 3 years, maintained at 5 years
Albright, Gilmartin, Swift, Krach, Ivanhoe, & McLaughlin (2003)
Level IV prospective case series study with no control, 3-month follow-up to 70 months
68 children with spastic CP, 73% were younger than 16 years
Intrathecal baclofen
Ashworth scales for spasticity
Spasticity decreased significantly and remained decreased for up to 10 years.
Wallen, O’flaherty, & Waugh (2004)
Level IV prospective case series study with no control, 3- and 6-month follow-up
16 children with spastic CP
Botulinum toxin (BOTOX)
Canadian Occupational Performance Measure (COPM), Goal Attainment Scale, Assessment of limb function, Child Health Questionnaire, parent questionnaire, Modified Ashworth Scale, ROM
Improved on COPM, no change on the assessment of limb function or Child Health Questionnaire, reduction of muscle tone that returned to baseline at 6 months. No change in ROM.
sion, increased hand function. The evidence suggests that hypertonicity is decreased with weight bearing, allowing for improved active elbow, wrist, and finger extension. In addition, the Barnes studies show improvements in hand function. These findings have limited validity and should be confirmed by more rigorous study.
N EURODEVELOPMENTAL TREATMENT The effectiveness of NDT has been researched for the past 30 years. A number of these studies have used true
experimental designs (Level I); however, the majority have used quasi-experimental and pre-experimental designs (Levels II to IV) with small samples of convenience. In 2001, an extensive review of NDT efficacy research sponsored by the American Academy for Cerebral Palsy and Developmental Medicine was published in Developmental Medicine and Child Neurology. In this comprehensive review, Butler and Darrah (2001) synthesized the results of 21 studies. They concluded that 86 of 101 results (from 21 studies) were neutral or found an advantage for the comparison group; only 15 results favored NDT.
Efficacy of Interventions to Enhance Hand Function • 441 “With the exception of immediate improvement in dynamic range of motion, there was not consistent evidence that NDT changed abnormal motoric responses, slowed or prevented contractures or facilitated more normal motor development or functional motor activities” (Butler & Darrah, 2001, p. 789).
A historic perspective of NDT research that included hand function outcomes is helpful in understanding the effects of this approach. Two early studies, Carlsen (1975) and Scherzer, Mike, and Ilson (1976) found positive results when effects of NDT were compared with a contrasting therapy. Carlsen reported greater gross motor improvements in the NDT group, but fine motor improvement did not differ when NDT was compared with functional therapy. Scherzer and co-workers reported improvement in physiologic function, but fine motor skills were not specifically measured. Studies in the 1980s examined gross motor and social outcomes of NDT with children with CP. These studies included several clinical trials that did not support the benefits of NDT (Hanzlik, 1989; Palmer et al., 1988).
Small Sample Studies and Short-Term Effects A number of small sample or single subject studies have examined the short-term effects of NDT. Because the aims of NDT are to influence the child’s muscle tone and improve the quality of movement, short-term effects should be observed immediately after treatment. One OT study by DeGangi, Hurley, and Linscheid (1983) examined the short-term effects of NDT using a single subject design with four subjects. Each child received eight treatments consisting of 25 minutes of NDT and 25 minutes of nonspecific play. The children’s performance on specific goals was measured from videotapes made immediately after NDT or play. The repeated measures included postural tone, weight shift and weight bearing, transition movements, and functional skills. Consistent improvement after NDT or play was not observed for any of the children. Although this study validated use of qualitative measures of movements, it did not validate the short-term effects of NDT. Lilly and Powell (1990) studied the effects of NDT using two children with spastic diplegia, 27 and 32 months old. These authors applied play and NDT, alternating the two interventions (Level III study). To relate intervention effects to function, Lilly and Powell measured components of dressing performance. Among the measures was bilateral hand use. Performance did not differ after play or NDT. The authors noted that their results concurred with those of DeGangi and colleagues (1993) in that neither study showed significant differences between the effects of NDT and those of play activity on functional activity.
DeGangi (1994) implemented a case study design (level IV) to examine the short-term effects of NDT. DeGangi was interested in the specific effects of NDT and argued that measuring the immediate effects was an important step before large clinical trials. She believed that single subject designs were appropriate and useful for examining NDT effects because individual children vary in their performance and their limitations. DeGangi (1994) provided a detailed description of the goals and the techniques used to reach those goals. Successful performance on each goal as observed by the parent and the therapist was counted across observations. Of the three cases documented, one focused on fine motor performance in a 6-year-old child with right hemiparesis (the other cases focused on other domains, such as feeding). The goals included use of right hand as an assist to stabilize objects or materials, improve visual motor skills, and bilateral skills such as buttoning, zipping, and stringing beads. After 8 weeks of twice-a-week hour-long NDT sessions, the child’s performance improved but remained inconsistent. In another study that examined the short term effects of NDT, Fetters and Kluzik (1996) compared the effects of NDT with practice of reaching on eight children with spastic CP. Each child received 5 days of NDT and 5 days of practice. Kinematic analysis of reach was used before and after each intervention to measure smoothness and speed of reaching movements. Although there were no difference between NDT and practice of reaching, when intervention time periods were combined and pre- and post-differences analyzed, all children improved in reaching speed and smoothness. These short-term small sample studies do not support positive effects of NDT when compared with other interventions; that is, they found that NDT did not result in greater positive effects than play or skill practice. However, these Level III to IV studies should not be considered conclusive; primarily, small sample trials develop instrumentation and methodologies for larger-scale studies.
Clinical Trials of Neurodevelopmental Treatment In the past 20 years, clinical trials have investigated the effects of OT using an NDT approach on hand function outcomes. Two studies by Law and colleagues researched the effects of NDT OT and casting on children with CP. The first study (Law et al., 1991) used a 2 × 2 factorial design that examined the effectiveness of intensive NDT and casting separately and combined. The sample comprised 79 children (73 completed the study; 18 months to 8 years) from three treatment centers in Ontario, Canada. All children had CP that included spasticity of wrist and hand. Children with
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fixed contractures or severe developmental disability were excluded. The intervention period was 6 months. Children either received “intensive” NDT OT, defined as twice a week (90 total sessions) with a 30-minute-per-day home program or they received “regular” NDT occupational therapy, defined as once a week (sometimes less) with a 15-minute home program to be implemented three times a week. Children who received casting wore a bivalved inhibitive cast at least 4 hours a day. The cast immobilized the wrist in extension and did not include thumb or fingers. Details about the treatment were not provided. The measures included the Peabody Developmental Motor Scales-Fine Motor (PDMS-FM), the Quality of Upper Extremity Skills Test (QUEST), and range of motion of the wrist. The children were randomized into one of four groups: Intensive NDT plus casting, regular NDT plus casting, intensive NDT, and regular NDT without casting. Measures were taken at 6 months to capture immediate effects and 9 months to examine the long-term effects. Although the design called for 48 NDT sessions for the intensive NDT group, the mean number of sessions was 29, which was almost three times higher than the 11 sessions the regular NDT group received. Hand function as assessed by the PDMS-FM did not differ significantly among the groups at the 6- or 9month measure. However, using age equivalent scores on the PDMS-FM, changes for all of the groups appeared to be clinically significant (5.26 months at the 6-month measure and 6.33 months at the 9-month measure). The qualitative measure of arm and hand movements, the QUEST, was significantly different for the children who wore casts with NDT when compared with those who received NDT only. This difference was more significant at 6 months (p = 0.03) than at 9 months (p = 0.10). In a follow-up regression analysis, Law and coworkers (1991) found that positive outcomes related to parents’ estimate of their understanding, comfort, and compliance with the home program and the age of the child. Children who were younger and whose parents estimated compliance as high had better outcomes. This finding suggests that, when possible, therapists should initiate therapy at young ages and encourage parents’ participation in home programs. These researchers concluded that casting with regular NDT significantly improves the quality of upper extremity movements. These effects are only partially sustained over time. Differences in the intensity of intervention did not produce clinically or statistically significant differences in performance. One consideration in interpreting these results is that not all children in the intensive
therapy group attended intervention sessions according to the design frequency. Intensive therapy may not be practical for many families. The inclusion of casting appears to be critical as only children who wore casts demonstrated improved quality of movement. Law and colleagues (1997) completed a second study with similar goals. A primary difference was that the sample was younger (18 months to 4 years). Other than age, the criteria for the sample were the same. All of the subjects had moderate to severe upper extremity involvement with wrists held in a flexed position. The children did not have significant cognitive impairments as judged by their therapists. The final sample comprised 50 children who were randomized into two groups. A crossover design was used, with each group receiving a period of intensive NDT with casting and a period of regular or functional OT with no casting. The children were placed into one intervention for 4 months followed by a 2-month washout period, then were placed in the other intervention for 4 months. In the intensive therapy plus casting, the therapists used NDT principles of facilitation and handling to improve quality of movement. The casts were the same as in the previous study. The functional OT program focused on task analysis and facilitating skills needed for self-care, feeding, and play. NDT was provided twice a week for 45-minute sessions with a 30-minute daily home program and functional OT was provided once a week for 45 minutes. Outcomes were measured using the PDMS-FM and the QUEST. Law and others (1997) maintained detailed records of therapist adherence to the treatment protocol, child’s attendance, and parents’ report of implementing the home program. The goals for therapy using NDT were based on changing impairments and improving quality of movement. The goals for functional OT were more global and functional and included improvement in self-care and play skills. Analysis of their findings demonstrated no differences in PDMSFM scores when children received intensive NDT and casting versus when they received functional occupational therapy. In addition, QUEST scores did not differ by treatment as they had in the earlier study. When differences between pre- and post-tests on the PDMS-FM and QUEST for each group were examined, they were found to be both statistically and clinically significant. This study suggests that therapy designed to improve functional goals is as effective as therapy designed to improve quality of movement. How children achieve the goal may not be as important as the goal achievement itself. In functional occupational therapy, the therapist does not work to enhance motor components (e.g., a missing motor skill such as thumb opposition or
Efficacy of Interventions to Enhance Hand Function • 443 active supination), unless it interferes with skill performance. These critical foundational motor patterns (e.g., object release or active supination) are addressed in a functional context (e.g., drinking from a glass). NDT emphasizes quality of movement and facilitating normal patterns of movement; however, movements are practiced in the context of functional activities. Therefore, NDT and functional therapy may use the same activity with different emphases and different goals. This core similarity may produce similar outcomes. In summary, functional OT and intensive NDT both facilitated improved skills, and twice-a-week NDT did not result in greater skill achievement than once-aweek functional treatment.
CASTING AND SPLINTING Upper Extremity Casting Occupational therapists using NDT often advocate methods for inhibiting abnormal muscle tone and abnormal movement patterns. These inhibitory methods (e.g., positioning, casting, and splinting) are coupled with handling to facilitate specific movement patterns. They are sometimes applied to maintain intervention effects such as increased ROM. Use of casting and splinting as an adjunct to NDT has been examined. Casting an extremity is believed to inhibit spasticity and improve ROM because it holds the muscle in a lengthened state. The inhibition is believed to be the result of neutral warmth and constant pressure. Case studies (Smith & Harris, 2002; Yasukawa, 1990) in which upper-extremity casting is applied for a short period of time (e.g., weeks) have reported improved ROM and function. Smith and Harris applied a bivalved inhibitive elbow cast to a 51/2-year-old with spastic quadriparesis. They found that casting reduced his elbow spasticity, increased facility in dressing, and increased the child’s tolerance for weight bearing. Yasukawa used a sequence of three phases of casting with a 15-month-old infant who had spastic hemiparesis. In the first phase, the involved arm was serialcasted for 4 weeks to improve ROM; then in a second phase, the uninvolved arm was casted to encourage active usage of the involved arm. In a third phase, a bivalved cast was used at night. These casting methods were applied over 11/2 years and resulted in increased scapular stability, increased shoulder flexion, and improved use of the involved arm during bilateral tasks. Cruickshank and O’Neill (1990) applied two types of casts and splints to an older child (11 years) with spastic quadriparesis (Level IV study). When a plaster cast was applied, elbow ROM improved. When a fiberglass cast combined with a plastic hand splint was applied, elbow ROM decreased. The authors inter-
preted the latter negative findings to relate to problems in stretching spastic muscles over three joints, to using fiberglass, which is more pliable than plaster (therefore, allowing some motion), or to lack of natural warmth in fiberglass compared with plaster. The effects of wearing a cast for 48 hours on quality of movement, ROM, and strength in an 8-year-old child were examined in a study by Tona and Schneck (1993). The child’s performance was videotaped before and after the cast was applied. Their findings demonstrated a significant reduction in spasticity on the first day that the cast was removed. However, in subsequent days, spasticity returned to baseline levels. The authors concluded that casting does appear to inhibit spasticity (as measured by passive resistance) when only applied for 2 days. Because the significant effects did not endure, the authors recommended that longer use of casting be considered. For example, a bivalved cast can be applied at night and periodically during the day. In an Australian study, the effects of upper extremity casting were studied using a sample of 11 children with hemiparesis or quadriparesis CP, 5 to 18 years old (Copley, Watson-Will, & Dent, 1996). The children were casted 4 to 6 weeks and immediately after casting, ROM increased and muscle tone decreased. An intensive post-casting program was then implemented. Six months post-casting, nine clients had maintained at least 50% of initial gains in passive or active range. Tone reduction was maintained in seven clients, and functional goals were either fully or partially achieved by 10 clients (Copley et al., 1996). In summary, in these Level IV studies, casting the arm appears to reduce spasticity and improve ROM for a short period. Long-term effects have not yet been determined through research. Long term, regular use of a bivalved cast may be needed to sustain the effects. Reduction of spasticity does not necessarily imply improved function, as the arm may remain weak or coordination may remain poor despite improved ROM. Functional outcomes, which were rarely measured in the studies described, should become an emphasis in future studies of casting effects.
Splinting Splints have been designed to reduce hypertonicity and improve function in children with CP. Exner and Bonder (1983) evaluated three different splints on a group of 12 children using a counterbalanced research design. Each of the splints had significant positive effects. The orthokinetic and MacKinnon splints demonstrated a greater effect than the short opponens; however, the former are rarely used in practice today. Although the short opponens was less effective in improving grasping skill, at present it is commonly
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applied on children with CP. The short opponens splint holds the thumb in opposition to the fingers and may be made of neoprene or thermoplastic materials. Reasons for its frequent use may relate to its appearance, ease of use and comfort. The effectiveness of the short opponens splint was evaluated by Goodman and Bazyk (1991) using a 4year-old child with moderate spastic quadriparesis. The volar splint of thermoplastic materials positioned the thumb in opposition by supporting it at the thenar eminence. Measures included active range of motion, grip strength, and pinch strength, dexterity, and prehension patterns. A 4-week baseline phase was followed by a 4-week intervention phase in which the child wore the splint for 3 hours in the morning and 3 hours in the evening. Using visual analysis of graphed data, improvements were reported in ROM, dexterity, and quality of movement. Changes in strength were not observed. Reid and Sochaniwskyj (1992) examined the effects of a hand positioning splint on arm and hand movements using a sample of 10 children with CP (Level II study). Analysis in three dimensions of reaching path length, movement latency, movement time, average velocity, and movement units recorded no significant differences when the splint was or was not worn. Although group differences were not significant, a number of the children demonstrated improved performance on a visual motor test when wearing the splint. The research on splints and casts is inconclusive given inconsistent results and weak research designs (primarily Level IV). Despite lack of rigorous studies, Teplicky, Law, and Russell (2002) concluded from a review of the research on splinting and casting, that casting consistently increases ROM. Whether or not the increased ROM equates to improved function is less clear. The effects of splinting are equivocal, with limited evidence that splinting improves hand function. In cerebral palsy, function is affected by limited strength, abnormal muscle tone, impaired sensation, difficulty in coordinating movements together, and in some children, limited cognitive ability. Intervention targeting one impairment may or may not improve function given that multiple systems contribute to functional performance (including sensory and cognitive). To confirm the effects of casting and splinting, large sample experimental design studies are needed.
CONSTRAINT-I NDUCED MOVEMENT THERAPY The theory for constraint-induced (CI) movement therapy is built on the concept of learned nonuse. Learned nonuse is hypothesized to occur after neurologic injury (DeLuca et al., 2003). After a neurologic insult, when an individual attempts to move the
involved extremity and fails, he or she learns ways to function using the uninvolved extremity and learns to compensate using only one hand. With nonuse, the ability of the involved extremity to move becomes permanently impaired and the sensorimotor cortex associated with arm and hand movement actually shrinks. In CI therapy, use of the nonaffected extremity is restrained such that the individual is forced to use the more affected extremity to accomplish functional tasks. Researchers have defined how constraint-induced movement therapy, which was developed for adults, has been modified and used successfully with children (Gordon, Charles, & Wolf, 2005). The approach involves restraint of the noninvolved extremity using a sling, sometimes a cast, and engaging the child in activities with his or her involved arm 6 hours a day (for 10 or more days). Generally groups of 2 to 3 children participate in therapist-led activities. Toys and activities are selected that can be successfully completed with the involved hand. The activities are graded from simple to more complex and can include board games, card games, manipulatives, puzzles, arts and crafts; each elected to encourage repetition of hand movements and skill building (Gordon et al, 2005). Families are encouraged to engage the child in bimanual fine motor activities at home (without the sling). The original evidence for the effectiveness of CI therapy was based on nonhuman primate research. After positive results with primates, it was then used with adults who had hemiparesis as a result of a cerebral vascular accident (Taub et al., 1993) and was first introduced for potential use with children in 1995 when Taub and Crago suggested that children may benefit from this intervention. A series of case studies and single subject designs were implemented in the late 1990s and early 2000s to investigate the effect of CI therapy with children, and since 2003, two experimental studies have been published.
Case Studies-Single Subject Designs Crocker, MacKay-Lyons, and McDonnell (1997) applied a single subject design (ABA) (Level III) to investigate the efficacy of CI therapy (which they termed forced use therapy) with two children with hemiparesis. They specifically selected children who used their involved arm as an assist and did not have major sensory deficits. The children who participated were 2 and 3 years old. They continued their regular once a week occupational and physical therapy during the 7week study. After a 2-week baseline period, the less involved arm was fitted with a custom resting splint that was worn most of the waking hours for 3 weeks. Measures were taken 2 weeks after CI therapy and 6 months later. One of the children did not comply with wearing the splint; therefore, results for only one child
Efficacy of Interventions to Enhance Hand Function • 445 were reported. Specific movement patterns were counted during a 15-minute play session. In addition, the parents kept logs of how often the involved hand was used in a finger feeding task. The results were graphed for analysis. Significant improvements were found in the use of the more involved hand for grasp and release, sensory exploration, and push-pull. When all involved hand movements were combined, they more than doubled from baseline to 2 weeks after CI therapy. This level of hand use was sustained at a 6-month follow-up assessment. Charles, Lavinder, and Gordon (2001) researched the effect of CI therapy on three school-aged children with hemiparesis. Each wore a cotton sling on the less affected arm, whereas the researchers encouraged use of the affected arm through play and functional activities 6 hours a day. After 14 days of CI therapy, the three children demonstrated improved performance in manual dexterity, sensory discrimination, and bilateral coordination. Two additional case studies of children using CI therapy have been reported (DeLuca et al., 2003; Pierce et al., 2002). DeLuca and co-workers reported a case study of a 15-month-old girl who had incurred a grade IV intraventricular hemorrhage and exhibited right hemiparesis. For a 2-week period, the girl wore a full arm bivalved cast on her unaffected arm except for an occasional removal for cleaning and ranging. A 6-hour intervention was implemented daily by a graduate student. In addition, the child received 4 hours of physical therapy each week. During the 6 hours of intervention, the child was encouraged to move her affected arm and was reinforced with praise. Measures given at the beginning and end of intervention included the PDMS-FM, a test of pediatric motor activity level (PMAL), and a Toddler Arm Use Test (TAUT). The PMAL is a semistructured interview administered every other day to the child’s primary caregiver. It obtains systematic data about 22 arm– hand functional activities. The TAUT is scored from a videotape. Specific movements of the affected hand are counted in 22 tasks/play activities. The PDMS-FM scores improved significantly. The parents reported that the child’s use of the involved arm improved from “poor quality of use” to “moderate quality of use.” Before intervention the child did not use her more affected arm on any of the free choice tasks; after intervention, she used the more affected arm spontaneously in 50% of the tasks. A second intervention was implemented 5 months after the first. The second period was carried out for 21 days and included 6 hours of intervention each day. The focus of intervention was refinement of hand movement to improve performance in play and functional activities. Scores on the PMAL and TAUT again
improved. The participant used her more affected extremity in 100% of free choice trials. In summary, this child changed from no spontaneous use of her affected arm and hand to regular and spontaneous use after the second intervention. The authors suggest that short, intensive periods of intervention should be considered as an effective method for improving function.
Clinical Trials Two randomized clinical trials of CI therapy have been completed. Willis and others (2002) implemented a study using 25 children with hemiparesis. A crossover design was used. A plaster cast was applied to the unaffected arm of the treatment group and was not removed for 1 month. The control group received no treatment. Fine motor skills of both groups were measured using the PDMS-FM before and after intervention. At 6 months after the first intervention the control group (N = 10) received the intervention and the group previously casted served as a control. For the first intervention period, changes in PDMS-FM scores were significantly different, with gains by the intervention group much higher than gains by the control group. These changes were sustained when measured 6 months later. The second group (who began CI therapy at 6 months) also made significant gains with intervention. Parents globally reported improved use of the affected arm. Several children did not tolerate the casts and the parents asked that they be removed. Taub and co-workers (2004) also completed a randomized trial (Level I) using 18 children. The CI therapy involved two components. The children in the intervention group were casted and the cast was bivalved for easy removal weekly. The intervention group also received 6 hours of therapy each day, implemented by occupational and physical therapists. Fine motor and daily living skills were shaped using therapeutic principles. The two measures, PMAL and TAUT, were reported earlier in the description of a case study by these same authors. The children who were casted improved significantly on the parent interview (rating both the amount of use and quality of use) and also improved significantly on the TAUT. Follow-up evaluation (using the PMAL) indicated that the gains were sustained over time. Taub and colleagues (2004) concluded that the CI therapy intervention produced “large improvement in the use of the more affected extremity.” The children gained 9.3 new motor behaviors in a 3-week therapy period. A critical therapeutic factor appears to be the concentrated extended nature of training conducted for many hours daily over consecutive weeks. The authors discuss the feasibility of concentrated doses of therapy. Because 6 hours of therapy each day is not reimbursed, not practical for busy families, and not feasible for certain
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children, research studies using less intensive therapy schedules are needed. In summary, virtually all of the studies of CI therapy, including two Level I studies, demonstrate its effectiveness in promoting hand function in children with hemiparesis. This therapy requires “forced,” intense practice of the involved extremity in various functional tasks. Most of the children appear to tolerate the casting or splinting procedures; the primary limitation appears to be in applying the intensive therapy schedule of 4 to 6 hours per day. Such a schedule is difficult for families and therapists alike, but may be feasible to implement on a short-term basis.
SURGICAL AND M EDICAL I NTERVENTIONS A number of surgical and medical procedures are applied to decrease spasticity and improve function in children with CP. Almost universally, these medical procedures are followed by occupational and physical therapy services (Dudgeon et al., 1994; Mittal et al., 2002a). Although most often these procedures are used to reduce lower extremity spasticity, they are sometimes used to reduce upper extremity spasticity. The effects of selective posterior rhizotomy, intrathecal baclofen, and botulinum toxin on functional hand skills in children with CP have been investigated using cohort research designs (Level IV).
Selective Posterior Rhizotomy This surgical procedure was originally designed to reduce lower extremity spasticity in children with CP or head injury. However, surgeons discovered that selective posterior rhizotomy (SPR) can have “suprasegmental effect” (i.e., change above the segmental spinal cord level of the cut nerve roots that affects upper extremity spasticity and function). Several studies have measured the effects of SPR on upper extremity and self-function (Dudgeon et al., 1994; Loewen et al., 1998; Mittal et al., 2002a,b). All of these studies are Level IV cohort studies without a comparison group. Loewen and others (1998) measured the effects of SPR on 37 children (mean age = 4.1 years) in the United Kingdom. The children were assessed using the QUEST and the Functional Independence Measure for Children (WeeFIM) before their surgery and 1 year after surgery. During this year, the children continued to receive their regular OT services. The mean improvement on the QUEST was 3.2 (P = 0.001) and on the WeeFIM was 11 (P = 0.001). These gains were clinically significant according to the parents who validated them in interviews. Dudgeon and co-workers (1994) also analyzed changes in self-care of children with spastic diplegia and quadriplegia after SPR. All children received physical and occupational therapy during the
follow-up period. This sample of 29 children was evaluated at 6 and 12 months after SPR. Self-care as measured by the Pediatric Evaluation of Disability Inventory (PEDI) improved in the children with spastic diplegia, but not in the children with quadriparesis. In the latter population, upper extremity function did not consistently improve. Fine motor outcomes of SPR on children with spastic CP were the focus of a Canadian study by Mittal and co-workers (2002a). These researchers examined the long-term effects of SPR using the PDMS-FM before and after surgery, and then 1, 3, and 5 years after surgery. In a second study, these researchers (Mittal et al., 2002b) reported findings using the PEDI at these same time frames. After surgery, the children received occupational and physical therapy. OT was provided once a week and focused on trunk control, positioning, fine motor and self-care skills. The final sample comprised 45 of 70 eligible patients (41 in the second study). After SPR, the children demonstrated statistically and clinically significant gains on both the PDMS and the PEDI that were maintained at 3 and 5 years. When the children were categorized according to the severity of their disability, more mildly involved children made greater gains. Self-care scores improved at 1 and 3 years, then stabilized between 3 and 5 years. Therefore, Mittal and co-workers’ (2002a,b) results support those of Loewen and colleagues (1998) that important improvements in self-care are derived from SPR, and children with milder disability make greater gains after surgery. In contrast to Dudgeon and coworkers (1994) fine motor skill also improved after SPR. Steinbok (2001) reviewed published outcomes of SDR for treatment of spastic CP. He concluded that given moderate level evidence confirms significant improvements in self-care and fine motor skills that appear to be sustained over time.
Intrathecal Baclofen and Botulinum Toxin In a descriptive report, Von Koch and others (2001) compared SPR results to those obtained using intrathecal baclofen. Intrathecal baclofen has a similar purpose to SPR (i.e., to reduce spasticity). Instead of cutting selective spinal nerves, baclofen is a synthetic gamma aminobutyric acid (GABA) that reduces excitatory synaptic transmission. This action on the spinal cord relieves spasticity. Intrathecal baclofen is administered using a permanent pump that is implanted into a subcutaneous pocket in the anterior abdominal wall. Although intrathecal baclofen is used most often to reduce spasticity of the lower extremities, it can be used to reduce spasticity of the upper extremities. Albright and co-workers (2003) examined the effects of intrathecal baclofen on 49 children. Spasticity was measured every 3 months for 2 years using the Ashworth scales.
Efficacy of Interventions to Enhance Hand Function • 447 The reduction in spasticity was significant and was maintained for up to 10 years without significant increase in baclofen. Functional measures were not used in this study and inclusion of OT as an adjunct to baclofen was not reported. Botulinum toxin (BOTOX) also has been used to reduce spasticity in children with CP. BOTOX is injected in muscles and produces a graded and reversible relaxation of overactive muscles by blocking the release of the neuromuscular transmitter acetylcholine. These treatments have evolved over time and at present higher doses are given and more muscles are injected. BOTOX has been shown to reduce spasticity for 3 to 4 months. It is injected into specific muscles and only works on those muscles. Neurosurgeons have indicated that occupational and physical therapy after SPR is of critical importance to achieve functional change, since movements are less restricted now because of reduced spasticity (Gaebler-Spira & Revivo, 2003). BOTOX treatment is repeatable if it is successful. Wallen, O’flaherty, and Waugh (2004) examined the functional outcomes of BOTOX with a focus on upper extremity movement. A convenience sample of 16 children with CP (2 to 12 years old) were assessed at 2 weeks and 3 and 6 months after injections. During this period regular OT was continued. In addition, electrical stimulation of specific muscles was applied. The measures included functional performance (Canadian Occupational Performance Measure), goal attainment scales, an assessment of upper extremity function, ROM, and a muscle tone scale. The children demonstrated significant improvement in functional performance and on their goals; however, upper extremity function and ROM did not improve. Muscle tone was initially reduced but returned to its original state by 6 months. This study suggests that BOTOX can improve functional skills, but may not improve upper extremity movement as measured by a qualitative assessment. SPR, intrathecal baclofen, and BOTOX effectively reduce spasticity using different physiological mechanisms. SPR results in a permanent change; in contrast, the effects of intrathecal baclofen and BOTOX fade over time and these medications must be readministered to continue to receive a benefit. Each treatment has been shown to improve upper extremity function and by extension to improve self-care. In the reviewed studies, children received occupational and physical therapy after the medical procedures. These rehabilitation services appear to be instrumental in helping children make functional gains once muscle tone is reduced and flexibility increased. However, few studies have reported hand function improvement and more substantial evidence is needed to support these treatments and to recommend them with confidence as a method for improving a child’s hand function.
CHILDREN WITH DEVELOPMENTAL COORDINATION DISORDER OR MILD DISABILITIES Children with developmental coordination disorders (DCDs) or dyspraxia form another group of children who typically have delays in hand function and who frequently receive OT services. Unlike children with CP who have difficulty with basic movements such as grasp and release, children with DCD generally have functional movement patterns but have difficulty with visual motor integration, bilateral coordination, rapid alternating movements, sequences of movement, and precise manipulation. This section describes efficacy studies of children who have basic hand skills (i.e., reach, grasp, release) but demonstrate difficulties integrating fine movements with sensory information to perform the higher levels of visual motor skills, manipulation, and bilateral coordination (Table 19-3). In children with DCD (this term encompasses dyspraxia for purpose of this chapter), daily living skills, such as fastening buttons and zippers, tying shoelaces, and handwriting are difficult to learn, may require excessive time to perform, or may be poorly performed. A variety of approaches have been used with children who have DCD including cognitive orientation to daily occupational performance, sensorimotor interventions, and practice of functional activities. This section describes efficacy studies of OT approaches to DCD in which hand function outcomes are a primary focus. Sensory integration practice models are not described here, as reviews of sensory integration efficacy have been published elsewhere (Mulligan, 2003; Parham & Mailloux, 2005; Vargas & Camilli, 1999) and generally the aim of sensory integration treatment is to enhance integration of foundational perceptual-motor functions (e.g., motor planning, visual perception, bilateral integration, and sequencing).
COGNITIVE ORIENTATION TO DAILY OCCUPATIONAL PERFORMANCE The originators of Cognitive Orientation to Daily Occupational Performance (CO-OP) recognized that cognition is important to the acquisition of occupational skills (Polatajko et al., 2001). In CO-OP, therapists assist children in developing cognitive strategies to improve their daily living skills. In contrast to many other OT approaches that emphasize sensorimotor activities and practice to gain skills, CO-OP uses a verbal approach to help children solve problems. The focus is to help the child learn to problem solve a motor task and learn strategies for accomplishing a motor task
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Table 19-3
Research studies examining the efficacy of interventions to enhance hand function in children with developmental coordination disorders
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Polatajko, Mandich, Miller & Macnab (2001)
Level IV pre- and postmeasures with intervention, no control
N = 13, children with developmental coordination disorder
Children were taught verbal self-guidance and to set goals
Functional goals; Developmental Test of Visual Motor Integration (VMI), Test of Motor Impairment (TOMI)
Achieved 9 of 10 goals. VMI and TOMI were not statistically different.
Miller, Polatajko, Missiuna, Mandich, & Macnab (2001)
Level I randomized clinical trial
N = 29, developmental coordination disorder. Age mean = 9 yrs
Cognitive Orientation to Daily Occupational Performance (CO-OP) for 10 sessions or “regular” OT approaches (control) for 10 sessions.
COPM, Performance quality, Vineland Adaptive Behavior Scales (VABS), BruininksOseretsky Test of Motor Proficiency (BOTMP), Visual Motor Integration (VMI)
COPM improved for both groups, but more for the CO-OP group. CO-OP also improved more in performance quality, and VABS Motor. Both groups improved on the BOTMP and VMI.
that can be generalized to other activities. In CO-OP, the child selects goals that he or she would like to accomplish. The child’s performance is assessed and the therapist determines what problems interfere with task achievement (e.g., the child may have difficulty with motivation, task knowledge, or performance). Then the therapist and child together develop a plan or strategy for accomplishing the task. Children are encouraged to talk their way through an activity. A number of facilitating strategies can be introduced, including altering body position, focusing on sensory aspects of the task, and attending to specific parts of the task. The child learns to self-evaluate so he or she can adapt the strategy or revise it when applying it again. The goal is that the child learns a strategy that results in success and that he or she can use independently in another situation. The efficacy of CO-OP has been investigated in small sample studies. Polatajko and others (2001)
reported a Level IV study of one aspect of CO-OP, Verbal Self-Guidance. Ten children participated in 13 one-on-one sessions in which they were taught to use verbal self-guidance to accomplish specific activities. The children were taught to develop goals and strategies to achieve specific activities. Most activities involved multiple steps of sequenced bilateral manipulation (e.g., making cookies, cutting, writing, keyboarding). In addition, specific motor skills were assessed using the Developmental Test of Visual Motor Integration (VMI) and the Test of Motor Impairment (TOMI). All of the children improved in the activities that they had targeted and 9 of 10 met the performance criteria established. Small changes in motor skills as measured by the VMI and the TOMI were not statistically significant. The effect size for the VMI was small (d = 0.16) and for the TOMI was moderate (d = 0.62). Given positive results from their pilot studies, Miller and co-workers (2001) completed a randomized clini-
Efficacy of Interventions to Enhance Hand Function • 449 cal trial of CO-OP (Level I). Twenty children with DCD, aged 7 to 12 years, were randomly assigned to one of two groups, CO-OP or regular therapy. The children had normal intelligence and the diagnosis of DCD as determined by an occupational therapist. In the 10 sessions of CO-OP, the children and therapist established goals and developed strategies to reach those goals. The therapists taught the children to use self-talk and to develop strategies to solve motor problems. Verbalization by both the child and the therapist was used to guide performance. The contrast group received regular therapy in which the therapist instructed the child, and provided skills direction and corrective instruction. The children who received COOP made significantly greater gains on the Vineland Adaptive Behavior Scale in the motor and daily living skills domains. The CO-OP group also improved more in upper extremity coordination as measured by the Bruininks-Oseretsky Test of Motor Proficiency (BOTMP) (p = 0.05) and in the visual motor integration as measured by the VMI (p = 0.065). (These positive findings were maintained when follow-up measures were made 9 to 10 months afterward.) Replication of these positive results with CO-OP appears to require children who have normal range cognitive skills and can use cognitive strategies to problem solve ways to improve performance (Miller et al., 2001). By using self-talk, the children may internalize strategies that help them succeed in other similar tasks. It is not clear what aspect of CO-OP leads to its success—the child’s own development of a plan and strategy, learning to use self-talk to guide his or her performance, or the process of the child discovering strategies that solve a performance problem.
OCCUPATIONAL THERAPY APPROACHES WITH PRESCHOOL C HILDREN Child-centered approaches have been used in interventions with preschool children. Preschool OT interventions tend to emphasize play occupations and social interactions, in addition to focusing on development of hand functions (Table 19-4). DeGangi and colleagues (1993) focused on these outcomes in a Level II study that compared child-centered therapy to structured sensorimotor therapy. The child-centered therapy emphasized the interaction between the therapist and the child and focused on the child’s interests. The child was allowed to explore and play with the therapist’s guidance. The goal was to promote exploration, creativity, and organization and interaction skills. Structured sensorimotor therapy involved the therapist giving the child specific instructions and directions and
teaching the child specific skills. The 12 children (3 to 6 years old) who participated had mild motor problems such as DCD, motor delays, and sensory processing disorders. Children with CP, major sensory impairments, severe medical problems, or severe cognitive delays were excluded. A crossover design was used, such that 6 children received child-centered activity and six received structured sensorimotor therapy for 8 weeks. They were assessed, and then the treatments were reversed for 8 additional weeks. Changes in hand function were measured using the PDMS-FM age equivalent scores. After the child-centered therapy, children gained 6 months in fine motor skills compared with 1.8 months gain during structured sensorimotor therapy. These differences appear to be clinically significant, but did not reach statistical significance. The Degangi and co-workers’ (1993) and Miller and associates’ (2001) studies support the importance of involving higher-level children in establishing the goals and leading the activity and the critical nature of involving the child in problem solving the task. Engaging the child’s cognitive abilities by encouraging discovery and problem solving (rather than simply following directions) seems to be important in the development of fine motor skills. As stated by DeGangi and co-workers (1993), fine motor skills depend on “motivation and drive to seek and explore objects in the environment. The process of experimenting with tools and learning the function of objects through creative play may be key components underlying hand function” (pp. 781–782).
The importance of play in therapy to children’s improvement in fine motor skills was also supported by Case-Smith (2000). In this Level IV study, 44 preschool children were evaluated before and after 8 months of intervention. The focus of the intervention and the measurement was fine motor function. The participants had delays in fine motor skills but no specific diagnoses (e.g., CP, autism, mental retardation, brain injury) and did not have severe sensory loss or health problems. In-hand manipulation, eye–hand coordination, visual motor integration, and fine motor skills were measured. Functional skills using the PEDI also were evaluated. After the 9 months of occupational therapy, the participants made significant gains in all fine motor measures. The number of therapy sessions and the types of activities that the occupational therapist implemented were recorded for each session. The number of sessions and percentage of therapy activities were used as predictors of the primary outcome variables. The two therapy activities that predicted the outcomes were use of play and peer interaction. These findings suggest that the therapist’s use of play and peer
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Table 19-4
Research studies examining the efficacy of interventions to enhance hand function in preschool children with sensorimotor delays
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
DeGangi, Wietlisbach, Goodin, & Scheiner (1993)
Level II crossover using a sample of convenience
N = 12, developmental delays, not severe disability; age = 36–71 months
Child-centered therapy emphasizing interaction and structured sensorimotor therapy for 8 weeks with crossover
PDMS-FM sensory integrative functioning, behavior, attention, play
Gain in fine motor skills was higher for child-centered therapy; gain in sensory integrative skills was higher for structured sensorimotor therapy; gross motor skills improved more with structured sensorimotor therapy; no definitive findings for behavior, attention, and play
Case-Smith (2000)
Level IV pre- and postintervention measures of one group
N = 44, mild delays; ages = 4–6 years, mean N = 57 mo
Occupational therapy emphasizing fine motor function
In-hand manipulation; eye–hand coordination Visual perception (DTVP); PDMS-FM visual motor (DTVP); function (PEDI)
Improvements in all assessments; interventions using play and social activities were most associated with visual motor and fine motor gains
Dankert, Davies, & Gavin (2003)
Level II quasiexperiment; sample of convenience
N = 43, 12 with disabilities who received OT, 16 typical children in OT, and 15 typical children; age = 3–6 years; mean = 53 months
Occupational therapy for two of three groups, 30 minutes of one-on-one and 30 minutes of group intervention for children with delays
(VMI) Visual Perception Motor Coordination
Children with delays who received occupational therapy improved in visual motor integration and visual perception, but did not improve in motor coordination more than children without disabilities.
interaction are important to achieving performance goals. This study supports the findings of DeGangi and colleagues (1993) and Miller and co-workers (2001) that incorporating play and social elements into therapy session promotes children’s fine motor skills and hand function. Play and social interaction may engage the
child’s attention, motivate the child to achieve higher skills, or infuse emotions into certain activities, encouraging the child to repeat and remember them. In another study examining the effect of OT on hand skills of preschool children with mild delays, Dankert and co-workers (2003) used a quasi-experimental
Efficacy of Interventions to Enhance Hand Function • 451 design (Level II). Three groups were compared, children with delays who received OT, children without delays who received OT, and children without delays who served as a control group. The researchers posited that visual motor skills are essential to school functions such as handwriting; therefore an OT focus on visual motor skills at the preschool age could serve as a preventive measure for future problems with handwriting. The researchers’ hypothesis was that 1 year of preschool OT services would promote gains in the visual motor skills of children with fine motor delays that would be comparable to gains made by children without disabilities. Similar to the Case-Smith (2000) study, regular OT services were provided (once a week for 30 minutes) for 9 months. This level of service is minimal when compared with other studies but is comparable to typical levels of school-based OT services. Children in all three groups made significant improvements from the beginning to the end of the year on the VMI test. The children who received OT intervention gained 7 standard points on the VMI compared with a 1-point gain by the group without disabilities; however, this difference was not statistically significant. This study demonstrated positive effects of OT services on visual motor skills development in preschoolage children when measured over time, and these gains were comparable to the progress made by children without disabilities (who did not receive OT). Effect sizes for the children who received OT were higher, and the standard scores for the children with OT services increased substantially more than they did in the test standardization sample or the other groups in the study. Evidence from Case-Smith (2000) and Dankert et al. (2003) supports the effectiveness of OT services in improving children’s visual motor skills. Limitations of these studies include lack of control and limited description of the intervention and lack of fidelity checks of the intervention. It was difficult to discern the theoretic models that guided the therapists in selecting and implementing intervention activities. Examining the effects of 9 months of intervention allows change to occur; however, long intervention periods also allow extraneous variables to interfere with the results, decreasing validity. Studies of OT as it is typically implemented with preschool children appear to effectively improve hand skills. When quasi-experimental studies are examined, hand skill outcomes of OT services are positive. These studies have significant limitations in that samples of convenience were used, fidelity measures of intervention sessions were missing, and outcome measures infrequently included children’s occupations. Future research should address these limitations.
INTERVENTIONS TO IMPROVE HANDWRITING Handwriting is an important school and life function. When handwriting is poor, the child may be penalized with poor grades on school work and written assignments. When handwriting is illegible, school achievement and self-esteem can be negatively affected (Graham, Harris, & Fink, 2000; Jones & Christensen, 1999). Individual differences in handwriting skills and handwriting fluency predict how much and how well children compose and express ideas in writing (Graham et al., 2000; Jones & Christensen, 1999). The production of written text requires the coordination of multiple skills. Visual motor integration appears to be a fundamental prerequisite (Cornhill & Case-Smith, 1996; Tseng & Murray, 1994). Manipulation and motor skills are also highly related to handwriting skills (Cornhill & Case-Smith, 1996; Graham & Weintraub, 1996). Given its importance to children’s success in school, a number of handwriting instructional approaches and interventions have been developed (see Chapters 14 and 15). Handwriting interventions vary in their theoretic model and the specific techniques and activities applied. In general, efficacy studies of handwriting interventions have demonstrated significant effects. This section reviews the experimental studies that have examined the effects of educational and therapeutic interventions designed to improve handwriting skills (Table 19-5).
I NSTRUCTIONAL APPROACHES Instructional approaches often follow behavioral principles, providing structure for learning, instructing children in practice of skills, and then providing feedback and reinforcement about the child’s performance. Generally, these approaches involve guided practice. Learning principles are followed but instruction generally does not consider individual differences among children. Berninger and co-workers (1997) implemented a comprehensive study of handwriting interventions based on different instructional methods. A randomized experimental design was used with a sample of 144 first-grade children who were identified as being at risk in handwriting. Five distinct instruction-based interventions were implemented. The first was motoric imitation in which the teachers modeled motoric acts but were nonverbal. In the second instructional approach visual cues were provided using numbered arrows to cue the sequence of strokes. The third instructional approach involved memory retrieval; the children were required to cover letters and write them from memory. The fourth instructional approach
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Table 19-5
Research studies examining the efficacy of interventions to enhance handwriting in school-age children
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Hayes (1982)
Level I randomized clinical trial
N = 45, in kindergarten and N = 45 in third grade, typical children
Five instructional conditions: copying with no prompting, visual demonstration with copying, visual and verbal demonstration with the child verbalizing during copying, control; one single 25minute session
Letter form reproduction
The most effective instructional method was visual and verbal demonstration with the child verbalizing. The least effective method (other than control) was copying only.
Blandford & Lloyd (1987)
Level IV ABC single subject
N = 2, learning disabilities; ages = 10.6 and 11.4
Self-instruction procedures. Students used card to guide their handwriting and to self-evaluate. In the final phase, the students did not use the card but were instructed to self-cue.
Mean number of words written; quality of handwriting
The students wrote more and the quality of their handwriting improved
Berninger, Abbott, Vaughan, et al. (1997)
Level I randomized experimental design, five-group comparison
N = 144, firstgrade children at risk for handwriting problems
Instructional approaches: motor imitation, visual cuing, memory retrieval, visual cuing and memory retrieval, copying without cuing, control group; 24 20-minute sessions were provided
Handwriting legibility, automaticity, dictation accuracy, writing fluency, and finger function
All intervention resulted in improvement in measures except automaticity. Visual cuing with memory retrieval was the most effective intervention.
Jongmans, Linthorst-Bakker, Westenberg, & Smits-Engelsman (2003)
Level II quasiexperimental in which controls and intervention groups were matched
N = 36 children in special education, 18 in each group; mean age = 9 yrs
Motor learning principles are taught; Selfinstruction and self-reflection on handwriting
Handwriting quality
Handwriting quality was significantly higher in children who received the instructional approach.
Efficacy of Interventions to Enhance Hand Function • 453
Table 19-5
Research studies examining the efficacy of interventions to enhance handwriting in school-age children—cont’d
Authors
Level of Evidence
Sample
Intervention
Measures
Findings
Case-Smith (2002)
Level II quasiexperimental
N = 38, 29 who received occupational therapy and 9 who did not; all with poor handwriting, third, fourth, and fifth grades
Occupational therapy, 9 hours of direct services over 9 months
Visual motor control; visual perception; in-hand manipulation; Evaluation Tool of Children’s Handwriting (ETCH)
Children who received intervention improved more in in-hand manipulation, visual motor control, and letter legibility. They did not improve more in handwriting speed.
Peterson & Nelson (2003)
Level I randomized clinical trial
N = 59, children with economic disadvantages; second grade; mean age = 7.1 yrs
Intervention group received occupational therapy 2/wk for 10 wks. Control group did not receive treatment.
Minnesota Handwriting Test (MHT)
Children in intervention scored higher on the MHT; specific gains were in spacing, alignment, and correct size. Speed did not improve.
Sudsawad, Trombly, Henderson, & Tickle-Degnen (2002)
Level I randomized experimental design with three groups
N = 45 children with kinesthetic deficits and handwriting difficulties, first grade; 15 in each of the three groups
One group received kinesthetic training; one received handwriting practice; one received no treatment. Treatment was 30 min/day for 6 days.
Kinesthetic acuity; kinesthetic perception and memory; the ETCH
Scores on the ETCH did not change. Kinesthetic perception improved for all groups, but was not significantly more improved in any one group. The teachers reported significant changes in handwriting for all three groups.
combined visual cues and memory retrieval. The fifth approach involved copying without any cueing from the teachers. In each instructional method, the letter was named twice on each teaching trial. In the control condition, children received phonologic awareness training with no practice of writing. The researchers predicted that children’s performance after intervention would vary with each of the different approaches and that visual cueing and memory retrieval would achieve the greatest handwriting automaticity. The interventions were implemented over 24 20-minute
sessions held twice a week. Measures included handwriting legibility, handwriting automaticity, dictation accuracy, writing fluency, and finger function. The interventions produced significant improvement in all handwriting assessments except the automaticity tasks and quality of one writing task. Visual cuing with memory retrieval was the most effective intervention across measures. Composition fluency improved in addition to handwriting legibility and improvements in handwriting skills appeared to have a positive effect on children’s ability to compose written text.
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Jones and Christensen (1999) also found that handwriting instruction can improve both handwriting and story writing (composition). This Level II Australian study involved 19 6- and 7-year-olds who demonstrated difficulty in handwriting speed and accuracy. A matched group of children without difficulties served as a control group. An 8-week intervention (10 minutes per day) consisted of instruction in letter formation with practice. The pre- and postassessments included writing speed and accuracy, handwriting formation, and a test of written expression. The group that received intervention improved more than the control group. In addition, the correlation between handwriting speed/accuracy and written expression was 0.73; that is, 53% of the variance in story writing was accounted for by speed and accuracy in writing letters. These researchers concluded that the intervention was highly effective; in addition, it was cost effective because the instruction required 10 minutes a day and was implemented by parents. This study also suggested that handwriting skill has an essential influence on composition in early elementary years. Hayes (1982) implemented a study that appeared to be the model for the Berninger et al. (1997) study. Two groups were used, 45 children in kindergarten and 45 in third grade. The children were randomly assigned to one of five conditions: control, copying with no prompting, visual demonstration with copying practice, visual and verbal demonstration with copying, and visual and verbal demonstration with the child verbalizing during copying. The children received these interventions for a single 20- to 25-minute session. Despite the short period for intervention, an effect resulted. Similar to the later findings of Berninger and co-workers, the intervention that involved visual and verbal demonstration with the child verbalizing while copying was most effective and copying with no prompting was least effective for both age groups. Self-instruction is an approach to improving handwriting that actively involves the child in the learning process. A number of researchers have examined the effects of self-instruction (Blandford & Lloyd, 1987; Graham, 1983; Kosiewicz, Hallahan, & Lloyd, 1981). Blandford and Lloyd examined the effects of using a written card that cued letter formation to guide two fifth-grade boys’ handwriting during journal writing. The card had self-evaluation questions to emphasize important aspects of correct handwriting. The students were to read the card and fill in answers based on their handwriting. Data were collected on correct letter formation and spacing for 25 days. The boys demonstrated improved handwriting (letter formation and spacing) when using the card and after using the card. Therefore, this method appears to yield a significant effect with minimal teaching and can be implemented
with groups, as well as individuals. A larger study of self-instruction was implemented in 2003 in the Netherlands. Jongmans and others (2003) researched the effects of a task-oriented intervention with selfinstruction on handwriting quality and speed in children with significant handwriting problems. These researchers completed two studies, one with 14 students in regular education (7 with poor handwriting [mean age = 7.9 years] and 7 with typical handwriting [mean age = 8.6 years], all of whom received the intervention) and a second with 36 students in special education (18 who received the intervention [mean age = 10.9 years] and 18 controls [mean age = 9.8 years]). An assessment of handwriting quality was used before and after the intervention. The children received 18 handwriting intervention sessions in the first study and about 48 sessions (6 months twice a week) in the second. The intervention used a self-instruction method in which the child reflected on his performance after each exercise. It consisted of multiple steps that emphasized visual perception of the letters, motor programming, repetition, and then practice of writing words and sentences. The child self-corrected his work at each step. In the first study only descriptive results were reported. All students with poor handwriting improved and those with normal handwriting did not change. In the second study, students who received intervention improved significantly in handwriting quality and improved more than students who did not receive intervention. Speed did not change for either group. Summarizing the significance of the effect, Jongsman and co-workers (2003) reported that 72% of the students changed from “dysgraphic” to “legible” after the intervention. This intervention is similar to the CO-OP intervention (Polatajko et al., 2001) described in the previous section, in that the child directs the activity, practices with self-guidance, and self-evaluates. Both interventions draw on the child’s cognitive skills and encourage active decision making and problem solving to master a motor skill. Both interventions produced strong, positive effects.
OCCUPATIONAL THERAPY APPROACHES OT approaches to improve handwriting often combine educational/instructional approaches with sensorimotor interventions. In practice OT intervention is individualized and based on analysis of the child’s performance. Unique to OT is a deep understanding of sensory and motor function, application of precise assessment of sensory perception and sensorimotor skill as it relates to handwriting, and implementation of interventions that are specifically designed to improve
Efficacy of Interventions to Enhance Hand Function • 455 sensorimotor functions. Case-Smith (2002) examined the effect of OT services provided in the school on handwriting legibility and speed. A sample of students in third, fourth, and fifth grades with poor handwriting legibility (N = 29) received services throughout a school year. A second sample of children in the same grades (N = 9) had poor handwriting by report of their teacher but did not receive OT services. The therapists documented their intervention throughout the year. A mean of 9 hours of direct services were provided and about 30% of all sessions included follow-up consultation with the teacher on the child’s behalf. The students were assessed using visual motor, visual perceptual, manipulation tests, the Evaluation Tool of Children’s Handwriting (ETCH) and two sections of the School Function Assessment (SFA). The students who received intervention improved more than the control group on in-hand manipulation and visual motor control tests. They also improved more in letter legibility, but not in handwriting speed. The improvement in handwriting legibility appeared to be clinically significant because two thirds of the sample moved from illegible handwriting (<85% of legible letters on the ETCH) to legible handwriting (>85% legible letters). As mentioned, handwriting speed did not improve, possibly because some of the students had learned to write more carefully and slowly to improve legibility. Peterson and Nelson (2003) also investigated the effects of OT intervention in a randomized clinical trial of children with economic disadvantages. Their sample consisted of 59 students in first grade, mean age = 7.1 years. They were assessed using the Minnesota Handwriting Test (MHT) before and after a 10-week intervention. Thirty children were randomly assigned to the intervention group and subsequently received 20 sessions of OT (twice a week for 10 weeks). The intervention was provided by OT students and each session consisted of practicing heavy work and sensorimotor activities, learning specific strategies to improve letter formation and spacing, and practicing handwriting. The gain scores on the MHT were significantly higher for the students who received OT. The effect size for the intervention group was large (ranged from 0.64 to 1.3 for MHT subsections) and the control group demonstrated no change. In follow-up analysis, the students made strong gains in spacing, placing letters on the line and using correct size; medium effects resulted for legibility and use of correct form. As in Case-Smith (2002), speed did not improve. Both studies (Case-Smith, 2002; Peterson & Nelson, 2003) demonstrated significant effects when comprehensive OT services were applied. The interventions combined sensorimotor activities that included
heavy work with practice of isolated skills and holistic practice of letter writing with feedback and reinforcement. These studies provide evidence that holistic OT improves handwriting but falls short of identifying the differential effects of specific intervention approaches. A study by Sudsawad and co-workers (2002) examined the effects of one aspect of a sensorimotor OT approach, kinesthetic training. These researchers assumed that kinesthesis can improve with training and that improved kinesthesis would lead to more legible handwriting. A randomized blended three-group research design was implemented. One group received kinesthetic training, one handwriting practice, and one no treatment. The measures were kinesthetic acuity, kinesthetic perception and memory, and the ETCH. The sample comprised 45 first-grade students with a kinesthetic deficit and handwriting difficulties. Kinesthetic training or handwriting practice was provided 30 minutes per day for six consecutive school days. Kinesthetic perception improved over time but was not different among the groups. Scores on the ETCH did not change between pre- and post-tests, indicating that kinesthetic and handwriting interventions had no effect on handwriting legibility or speed. The teachers reported significant changes in handwriting for all three groups. The authors concluded that their hypothesis that kinesthetic training would lead to improvement in handwriting was not supported. Limitations included the short intervention period (6 days) and small numbers in each group. In summary, educational/instructional approaches that use multiple sensory systems for cueing and feedback and that actively involve students have strong and consistent effects on improving handwriting. Specific instructional approaches with demonstrated effectiveness are those that engage the student in goal setting and reflection about performance, give visual and verbal cues, and require memory retrieval during practice. Less effective approaches are those that involved only copying, or only visual or verbal cueing. Instruction approaches appear most effective for improving and writing quality and composition fluency, and least effect for increasing speed. OT approaches that are comprehensive, provide multisensory input, and engage the child in activities that reinforce multiple dimensions of handwriting (e.g., motor planning, visual motor integration, small muscle movement of the hand) effectively improve handwriting legibility. There is no consistent evidence that OT interventions improve handwriting speed. Composition and writing quality have not yet been assessed in OT studies, but should be considered given its importance as primary outcomes of children’s writing skill. When a single component (i.e., kinesthesia) is the emphasis of intervention, the effects are equivocal.
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As in the educational studies, use of a single learning method that emphasizes a single sensory system does not appear sufficient for effecting substantial improvement in handwriting.
SUMMARY Research evidence about treatment effects helps practitioners make good clinical decisions, provides practitioners with explicit information to give to families, and helps practitioners justify treatment decisions to physicians and other professionals. When levels of research evidence are high and rigorous methods are used, therapists can generalize the findings to their practice with confidence. When levels of research evidence are low, findings should be reported and applied with caution because of inherent limitations. The majority of studies on hand intervention effectiveness are Levels III and IV and use small convenience samples. These single-subject and case studies provide detailed information about treatment outcomes for individuals, but cannot be generalized beyond the characteristics of the children who participated. Although case studies and single subject design studies deepen understanding of intervention effects, they do not provide definitive information from which predictions about outcomes can be made. In the past decade more rigorous (Level I) randomized clinical trials have been completed, providing more definitive findings and making important contributions to the knowledge base for hand function intervention outcomes. The studies reviewed in this chapter examined various levels of function and disability. Many hand intervention studies have examined impairment level (body structure and body function) outcomes. For example, the studies of upper extremity weight bearing examined ROM, muscle tone, and movement patterns (i.e., components of performance). Studies of casting also emphasized ROM and muscle tone. Even studies of comprehensive interventions (e.g., neurodevelopmental treatment) often used measures of arm and hand movement rather than functional or occupational measures. Impairment-level outcome measures leave unanswered questions about if and how performance and function changed given intervention effects. Measures of function and occupation, in addition to performance of specific skills, help to link interventions to children’s daily lives and social roles. Researchers (Butler & Darrah, 2001; Law & Baum, 2001) have suggested that outcome studies routinely couple specific performance measures with holistic, comprehensive assessment of function and occupation. Examples of holistic assessments to be included are those that
measure functional goals (e.g., the Canadian Occupational Performance Measure), self-care and mobility function (e.g., Pediatric Evaluation of Disability Inventory), adaptive behavior (e.g., the Vineland Adaptive Behavior Scales), or use of hands in play (e.g., the Toddler Arm Use Test). Measures of play skills, playfulness, or quality of life also should be used in association of measures of sensorimotor skill. Specific studies reviewed in this chapter did use functional and occupational assessments. For example, Miller and co-workers’ (2001) study of cognitive orientation to daily occupational performance implemented the Canadian Occupational Performance measures, the Vineland Adaptive Behavior Scale, the BruininksOseretsky Test of Motor Proficiency, and the Visual Motor Integration test. These assessments examined broad aspects of function and the child’s integration of sensorimotor-perceptual-cognitive skills. The findings that resulted answered questions about the children’s occupations after intervention. Other studies that examined the effects of holistic interventions (e.g., preschool OT services [Case-Smith, 2002]) demonstrated the associations between children’s performance of basic skills and their functional outcomes. Future hand intervention research should examine children’s play and school outcomes to determine effects on everyday life and children’s roles as students, play partners, and family members. Another limitation in interpreting the research literature is that the independent variable, the hand function intervention, is rarely described in detail in the research report. As a result, it is not clear exactly what intervention strategies were used and to what interventions the study results apply. In order to assure that the intervention is true to its theoretic model and is reliably applied across researchers and time, measures of treatment fidelity are needed. Almost none of the studies used checks on treatment fidelity; consequently, the external validity of findings can be questioned, as treatment protocols are easily and unintentionally altered during implementation. Certain interventions (e.g., neurodevelopmental treatment) have been defined differently over time (Howle, 2002); therefore, explicit information about what intervention activities and strategies were administered is provided in the research report. Publications of standard or best practice intervention models can be used to define interventions in clinical trials. A final limitation observed in many of the studies was lack of long-term follow-up. Often studies implemented a post-assessment immediately after intervention, and did not follow children’s progress to determine the long-term effects of intervention. Outcomes of children’s occupations and roles as they enter adolescence and adulthood have rarely been
Efficacy of Interventions to Enhance Hand Function • 457 assessed. This deficiency is not surprising given that long-term follow-up of subjects requires substantial resources and efforts of research teams. Although these long-term projects have yet to be accomplished, the preliminary data reported in this chapter can justify and inform these large-scale projects. Professions focused on hand intervention research are moving toward more rigorous studies and designs that provide strong, valid findings. To increase knowledge of hand intervention effectiveness future research studies should: 1. Use randomized clinical trial designs with large sample sizes. 2. Implement measures of occupation and function that represent meaningful outcomes and quality of life for children and families. 3. Implement methods to evaluate intervention fidelity and ensure that interventions represent the theoretic constructs from which they are derived. 4. Follow children over time to measure long-term outcomes. Summarizing the findings of research on interventions to promote hand function is difficult at best, given vast differences in study designs, samples, techniques, and environmental contexts. This body of research should be carefully read, critiqued, and digested. When carefully analyzed, these studies offer explicit guidance to practitioners who provide services to children with delays in hand function and to scholars who will take the next steps in research of intervention outcomes.
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Glossary
Adapted tripod grip: Grip where the pencil is stabilized within the narrow web space between the middle and index fingers when writing. Affordances: The perceptual features of objects, places, and events that enable particular functional actions. Anticipatory control: The programming of action based on a mental representation of an object’s properties that has developed through prior experience. It involves the activation of sensory and muscular systems for a specified activity that has been learned. Arches of the hand: The musculoskeletal structures that allow the flattening and cupping of the hand. The arches are the proximal transverse, distal transverse, and longitudinal. Attention: An active process in which certain stimuli in the environment are given preference over other stimuli depending on their perceived importance. Automatization; autonomous phase: The stage of a learned motor skill when the action is carried out with minimal attention. Base of support: The area of the body in contact with the support surface; when more body area is in contact with the surface, the base of support is wide; when less body area is in contact with the surface, the base of support is narrow. Bilateral hold, cooperative: An action in which one hand supports or stabilizes an object while the other hand explores or manipulates it. Bilateral or two-handed hold, symmetric: Holding objects with the two hands acting in unison. Bilateral simultaneous manipulation; complementary two-hand use: An action in which both hands are performing different but complementary actions at the same time, as in bead stringing. Central pattern generators: Neural networks that interact in an organized manner to produce a motor act. Cognition: The collection and organization of information into knowledge.
Coincidence anticipation: A form of anticipatory control in which movement coincides with an external event, such as catching a ball. Composite flexion: Fisting of the hand along with flexion of the wrist, thereby putting maximal strain on the extensor mechanism of the hand. Concept formation (knowledge): Conscious and active process that categorizes sensory information by associating it with conceptual categories. Constraint-induced movement: Immobilization of the less involved upper extremity to require the child to use the more involved extremity. Constructional skill: The ability to perform the sequences of movement involved in producing twoor three-dimensional representations, as in drawing or building. Constructional style versus contoured style of drawing: Refers to the execution of pictorial representations by the assembly of simple forms as opposed to beginning with a sketch of an outline. Dexterity: Ability to manipulate objects with the hands with accuracy and speed. Disk grip (five-jaw chuck): A fingertip grip using the pads of all the fingers and the thumb, as on the lid of a jar. Dissociation: Refers to the ability to carry out precise, independent joint movements without concurrent involuntary actions at other joints not involved in the task. Dorsal stream: Neural pathway that provides visual information for the guidance of movement. Dual motor systems: Refers to the differentiation between central nervous system control of skilled distal movements such as those of the hand and the proximal movements of the limbs and trunk. Dynamic splinting: Uses articulations and force components to constantly put a dynamic pull on tight or healing tissue; often incorporates rubber bands, springs, or other materials to exert controlled mobilization. Dynamic tone: The muscle tone that occurs with volitional movement.
461
462 • Glossary Dynamic tripod grasp (pencil): Grasp in which the pencil is stabilized against the side of the middle finger by the pads of the thumb and index finger. Writing includes localized movements of the fingers and thumb as well as the wrist.
differentiated from writing, which is the composition and control of material that is handwritten. Haptic perception: Recognition of objects and object properties by the hand without the use of vision.
End range of movement: The distal range of motion at a joint as opposed to movements that occur in the middle of available range. Executive function of the hand: The use of the hand as a means of practical action on the environment, during which perceptual function is regulated by whatever is needed to achieve the action. Explicit (declarative) memory: Conscious awareness and intention to recall facts and events. Extensor lag: Inability to extend the DIP joint of the finger into full extension because of poor pullthrough of the terminal extensor tendon. Eye–hand coordination: The integration of visual perceptual information with the purposeful movements of the hand and arm.
Implicit (procedural) memory: Storage and recall of information without conscious awareness. Knowledge of how a task is done expressed through performance. Inferior or immature pincer grasp: A grasp between adducted thumb and side of the index finger. In-hand manipulation: The adjustment of a grasped object within one hand while it is being held. Includes translation, shift, and rotation with and without stabilization. In-hand manipulation with stabilization: Manipulating one object with the fingers while holding one or more additional objects within the same hand. Intermodal perception: The matching of objects or shapes that are perceived by one sensory modality, such as touch, to those which are perceived by a different sensory modality, such as vision. Intramodal perception: Matching objects or shapes within a single sensory system, for example, matching one object explored haptically to another also explored haptically.
Feedback: Sensory information that arises from movement. Fine motor coordination: Use of small muscle groups for precise movements, particularly in object manipulation with the radial digits. Finger differentiation or individuation: Controlled individual or isolated finger movements. Fixing: Volitional limitation of freedom to move at various muscles and joints in order to produce controlled movement in another body part.
Kinesthesia: The conscious perception of the excursion and direction of joint movement and of the weight and resistance of objects.
Graphomotor skill: The conceptual and perceptual motor abilities involved in drawing and writing. Grasp phase of reaching: The phase of reaching for an object in which the hand is shaped in anticipation of the contact with the object. Grip: The mechanical component of prehension; the hand configuration on the object during grasp. Grip force: The pressure exerted on an object in the act of lifting and holding. In precision grasping, grip force is matched to object qualities such as weight, texture, and rigidity.
Lateral tripod grasp (pencil): Grasp in which the pencil is stabilized against the side of the middle finger, with the index finger pad on the pencil, and the thumb adducted with the thumb pad braced on the side of the index finger. Writing includes localized finger movements as well as wrist and arm movements. Learned non-use: When the more involved extremity is not used, changes occur in the central nervous system that reinforce the non-use of that hand.
Hand preference: The consistent favoring of one hand over the other in the performance of skillful acts. Hand shaping: The adaptation of the hand arches and the finger postures to the object’s size, shape, and use in anticipation of grasp. Handedness: Consistent and more proficient use of the preferred hand. Its dimensions include hand preference (the hand chosen more often) and hand performance (the hand with superior ability). Handwriting: The process of transcribing letters to form words and words to form sentences;
Memory: Process by which knowledge is encoded, stored, and retrieved. Mirror movements: Movements of the hands are coupled, with the use of one hand the same movements are observed in the second hand. Motor functions of the two sides of the hand: Refers to the differing functions of the ulnar (little finger) side and the radial (thumb) side of the hand. The primary function of the ulnar side of the hand is to hold, whereas that of the radial side is to manipulate.
Glossary • 463 Motor learning: A set of processes associated with practice or experience leading to relatively permanent changes in the capability for producing skilled action. Movement unit: Constituted by one phase of acceleration of a limb followed by a deceleration. A movement can consist of one or more movement units. Multimodal exploration: The simultaneous use of more than one sensory system in object exploration. Occupation performance: Performance of skills that are essential for independent functioning in everyday living. Palmar grasp: A whole-hand grasp in which objects are held against the palm of the hand by the fingers. The thumb may be active or passive. Palmar grasp (pencil): A grasp in which the pencil is positioned across the palm and held in a fisted grip. Pathologic handedness: Altered handedness resulting from neural insult. Perception: A process of collecting information from the environment based on vision, touch, hearing, and proprioception in order to construct an internal representation of the environment and body. Perceptual activity of the hand: Use of the hand as a perceptual system, in which motor activity is primarily exploratory and information seeking. Perceptual-motor processes: The reciprocal relationship between perception and action, wherein movement adapts to perception and movement influences perception. Pincer grasp; pinch; fine prehension: The grasp of an object with the index finger and thumb. Major types include palmar pinch (pad of finger to pad of thumb), tip pinch (using tips of both thumb and finger), and lateral pinch (thumb holding object against side of finger). Postural control: The maintenance of body position in space that evolves from the development of antigravity movement, postural adjustment reactions, and somatosensory input. Power grip: A static grip applying force to an object to immobilize it in the hand. Praxis: The planning and execution of a motor movement or a series of motor movements/tasks. Precision grip: The grasp of an object with the finger and thumb pads or tips. Precision grips may be static but often allow movement of the object by or within the fingers. Precision handling: The dynamic or manipulative characteristics of precision grip used for in-hand manipulation and for the use of many tools. Prehension: The voluntary act of grasping and manipulating objects with the hand.
Preprogrammed movement/open loop movement: A learned movement in which the entire motor pattern is programmed before the movement is initiated and which is not under sensory control during execution. Prereaching; prefunctional reach: The more automatic movement of the very young infant’s hand toward an object before voluntary reach has developed. Proprioception: Sensory information about positions and movements of body parts from muscles, tendons, joints, and skin. Limb position sense and kinesthesia are forms of proprioception. Quadripod grip (pencil): Grip in which the pencil is held by three fingers and the thumb. May be static or dynamic. Radial digital grasp; inferior forefinger grasp: Prehension of an object with the thumb, index, and middle fingers but with the object held proximal to the finger pads. Thumb may be in adduction or opposition. Radial palmar grasp: An immature grasp in which the index and middle fingers and thumb press an object into the palm. Radial-ulnar dissociation; separation of the two sides of the hand: The ability to perform holding functions with the ulnar fingers while manipulating objects with the thumb and radial fingers. Reflexive grasp: The stereotypic closing of the hand on an object in response to tactile or proprioceptive information. Palmar grasp reflexes occur normally in early infancy and may persist in children with brain damage. Reverse transverse grip; radial cross-palmar grasp (pencil): An immature pencil grip with the pencil positioned across the palm and the point projecting from the thumb side of the hand. The hand is fisted with the forearm fully pronated. Rotation: An in-hand manipulation movement by which an object is turned in the fingers. Simple rotation involves turning or rolling the object 90 degrees or less with the fingers acting as a unit. Complex rotation involves turning an object 90 to 360 degrees using isolated finger and thumb movements. Scissors grasp: The prehension of small objects between the thumb and the lateral border of the index finger. Self-care activities: The basic daily living activities of eating, dressing, bathing, and use of the toilet. Sensory processing: The management of incoming sensory information by the central nervous system.
464 • Glossary Shift: An in-hand manipulation movement where there is slight adjustment of an object on or by the finger pads. Somatosensory: Refers to the tactile and proprioceptive senses that contribute to the perception of objects and events, as well as of the body and limbs. Spasticity: Velocity-dependent resistance to passive movement. Squeeze grasp: An immature grip in which an infant presses an object against the palm with total finger flexion. The thumb does not participate and force is not modulated. Stabilizing: Contraction of the muscles to fixate or hold the body or a body part; also refers to the use of external systems or devices to provide support when an individual is unable to do so alone. Static splint: An immobilization or supportive splint that has no moving parts; serial static splints are periodically remodeled as the joint gains motion; static progressive splints use low load in a single direction over a long period of time to mobilize soft tissue at its end range. Static tripod grasp (pencil): Grasp in which the pencil is stabilized against the side of the middle finger and held by the pads of the index finger and thumb. The hand is moved as a unit by the wrist and forearm in writing. Stereognosis: The recognition of familiar objects through touch. Stiffness: A general term referring to difficulty moving the limbs. Switched handedness: Occurs when an inherently left-handed child learns to draw and write with the right hand because of sociocultural influences. Tapping: A facilitation technique that is manually applied and used to generate volitional movement at individual muscles. Three-jaw chuck: A power grip of the fingertips. The object is held with the distal pads of the thumb, index, and middle fingers. Threshold tests: Tests that determine the minimal stimulus a person can perceive (e.g., pain, temperature, pressure).
Tone: The resistance a muscle offers to being lengthened; abnormal tone is a result of both neural factors (e.g., spasticity) and biomechanical factors (e.g., fibrosis and atrophy), which cause changes in contractile properties of some muscle fibers. Total end range time: Term used in soft-tissue adaptability that refers to the frequency of stretching multiplied by the duration of the stretch at the end range of a joint’s movement. Trajectory: The path taken by the hand as it moves toward a target and the speed at which it moves along the path. Translation: A form of in-hand manipulation by which an object is moved in a linear direction between the palm and the fingertips. Includes the movement of an object from the palm of the hand to the fingertips (palm-to-finger translation), and the movement of an object from the fingertips to the palm (finger-to-palm translation). Transportation phase; transport: The phase of reaching that brings the hand to the target or moves an object through space. Ventral stream: Neural pathway that provides visual information for the recognition of objects. Visual-motor integration: The coordination of visual information with movement. The term is used often to indicate the ability to copy geometric forms. Volition: Action in which the achievement of a goal is seen as resulting from one’s own activity. Voluntary controlled release: Letting go of an object in a specific place and with timing that is appropriate for the specific task. Weight shift: Volitional or assisted movement of body weight which occurs with movement of a body part. Working memory: Short-term memory system that holds information so that it can be manipulated during tasks. Zone of proximal development: A period of developmental maturation in which particular skills are within reach of a child.
INDEX A Abductor pollicis muscles, 31-34, 33f, 35f Acceleration illustration of rates of, 56f Accordion tube toys, 271 Active range of motion (AROM), 370, 371f, 373 Activities of daily living (ADLs) for burn victims, 393 evaluation of following hand wounds, 376, 377t-379t handedness issues with, 183-184 and self-care, 193-214 Adaptations for hand skill problems, 240-241 reaching and motor impairments, 96-97 Adapted tripod grip, 331f, 461 Adductor pollicis muscles, 34-35 Adults drawing skills in, 220 haptic manipulation strategies in, 70-71 reaching movements by, 94-95 role of vision and cognition in haptic perception, 74-76 Afferent feedback, 47-48, 218 Affordances, 461 Alpha motor neurons of hand muscles direct corticospinal connections to, 4-5 Ambidextrous definition of, 166b Anatomy of the hand, 21-43 Anterior intraparietal sulcus importance in movement, 16 Anticipatory control development of, 52-53 during infancy, 94 in developmentally disabled children, 56-57 glossary definition of, 461 and learning, 47 Anticipatory postural control, 346 Anticipatory scaling, 57
Page numbers followed by f refer to figures; those followed by t refer to tables; and those followed by b refer to boxes.
Anti-Houdini techniques, 419, 420b, 420f-422f Arches of the hands, 22, 23f, 461 Arms embryonic development of, 21-22 extrinsic muscles and tendons of, 27, 28f-29f, 29-31, 32f functions of kinesiologic aspects of, 349-348 isolated movements of, 247-249 Arousal, 104 Assessments of cerebral palsy, 351-352 of children’s drawings, 225-226 of hand injuries activities of daily living, 376 hand dexterity, 374-375 hand sensibilities, 376 hand strength, 373-374 interview and history, 370 pain, 375-376 range of motion, 370-373 wounds, edema and scarring, 375 of handedness by occupational therapists, 179-180 of handwriting skills, 291-307, 302t-305t, 311-318 of haptic perception in infants and children, 77-78 of self-care skills, 195-196, 197, 199 Attention definition of, 104, 461 in motor skill, 242 Attention deficit hyperactivity disorder (ADHD) affecting reaching in children, 96 impaired hand function with, 54-58 prehensile force control in children with, 45-46 Autism and haptic perception, 81-82 Autism Spectrum Disorder, 278 Avoiding reactions, 130 B Balance development of in infants, 122-124 and reaching, 93 Base of support, 461 Bead stringing, 153f, 273-275, 324
465
466 • Index Bilateral hold cooperative definition of, 461 Bilateral integration and sequencing (BIS) dysfunction, 326-327 Bilateral skills difficulties interventions for, 260-262 of manipulation, 256 needed for hygiene and grooming, 210, 211t, 212t sample short-term goals for, 244, 245b and self-care, 213 transitional, 131-134 Bimanual skills from birth to 12 months, 131-134 coordination of, 134 developmental sequence of birth through 24 months, 138t-139t and hand preference, 164 Blocked range of motion (BROM), 370, 371f, 373 Blocking gloves, 387f Bobath approach, 343, 344-347 Body charts to identify pain, 376 Bones anatomical diagram of hand, 22f embryonic development of, 21-22 Botulinum toxin (BOTOX), 447 Boutonniere deformities splinting, 418f Brachial plexus injuries, 418 Brain injuries and haptic perception problems, 81 Bristle blocks, 272, 277 Brodmann’s areas, 8-9, 10f Bruininks-Oseretsky Test, 231, 449 Buddy taping, 417 Burns in children classification of severity, 392-394, 390t closed wound scarring phase of, 392-394 open wound phase of, 390-392 patterns of, 389-390 management of scars, 391-393 Buttoning, 154, 208, 209t, 210, 273, 275-276, 276-277 C Callosal dysfunction, 176 Capacity definition of, 104 Capitate anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Carpal bones diagram illustrating, 22f embryonic development of, 21-22 Carpometacarpal joints anatomy of, 23, 24, 25f and handwriting, 322 Carpus, 23, 24f, 25f Case studies on cognition and motor skills, 101-102 concerning cerebral palsy and neurodevelopmental treatment (NDT), 355-359
Case studies (Continued) concerning low muscle tone, 360-363 on preschool fine motor skill development, 285-286 on radial nerve palsy and splinting, 423-425 Casts; See also splinting efficacy of research studies on, 443-444 Friedrich and Baumel, 388f full arm, 380f as intervention adjunct, 263 “Caterpillar pop” game, 271 Central nervous system (CNS) and haptic perception, 69 and prehensile force control, 45-46 Central pattern generators, 461 Cerebral cortex and hand-object interactions, 3-4 Cerebral palsy (CP) affecting drawing abilities, 225 affecting grip force, 11, 54-58 anticipatory and postural control with, 346 assessment process, 351-352 biomechanical interactions of upper limbs with, 348-349 causes of, 344 definition of, 344, 434-435 hemiplegic reaching problems with, 97 hypertonia versus hypotonia, 349 impaired hand function with, 54-58 impairments seen with, 344 lift capacity of children with, 50f neurodevelopmental treatment (NDT) case study, 355-359 description of, 343-363 research studies, 440-443 prehensile force control in children with, 45-46 research studies on, 435, 436t-440t treatment planning, 352, 357t, 361t Checkrein ligaments, 27 Children anticipatory control development in, 52-53 with cerebral palsy (See cerebral palsy (CP)) drawing skills in, 220-221, 222f, 223-224 graphomotor skill acquisition in, 217-220 grasping coordination of, 48-51 hand therapy in, 367-398 congenital problems, 394-398 evaluation of, 369-376, 377t-379t introduction to, 367-368 phases of wound healing, 368-369, 370b thermal injuries, 389-394 traumatic injury treatment, 376, 380-394 handedness in assessment of, 170-172 classification of, 165-168 definition of, 161, 162, 163f, 164 development of, 177-179 factors influencing, 172-177 flow chart illustrating, 163f introduction to, 161-162 left and switch, 168-169 and pediatric occupational therapy, 179-184 prevalence of, 169-170 haptic manipulation strategies in, 73-74, 76-77
Index • 467 Children (Continued) haptic perception development in, 65-67 illustration of hand ability in, 46f interventions for hand skill problems, 239-264 with motor impairments reaching/coordination problems in, 96-97 object manipulation development in, 154-158 prehensile force control development in, 45-46 preschoolers fine motor program for, 267-287, 289-291 role of vision and cognition in haptic perception, 74-76 using sensory information for reaching, 95 Children’s Handwriting Evaluation Scale (CHES), 302t-305t, 314-315 Chinese speed test, 304t-305t “Chunking,” 106, 108 Clot formation, 368-369, 370b Clumsiness causes of in children, 54-58 Cock-up splints, 381f Cognition definition of, 461 development of, 45, 110 factors in self-care, 214 and hand ability in children, 46f importance of for motor skill acquisition, 102-103 and motor skills adaptation, 102 attention and perception, 104-105 case scenario, 101-102 concept formation, 106-107 importance in acquisition of, 102-103 memory, 107-108 perceptual-motor processes, 105-106 processes of, 103-108 problems with cerebral palsy, 344 role in haptic perception, 74-76, 77 Cognitive neuroscience approach to cognition and motor skill development, 103 Cognitive Orientation to Daily Occupational Performance (CO-OP), 447-449 Cognitive skills; See cognition Coincidence anticipation, 461 Collagen, 368-369, 370b Collateral ligaments accessory, 25, 26f cord portion of, 25, 26f splinting of, 383-384 Columnar carpus, 23, 25f Communication using hands, 101 writing, 291 Complementary two-hand use, 152-153, 158 Composite flexion, 461 Computers and drawing, 224-225 and handwriting, 232 Concept formation definition of, 461 description of, 106-107
Congenital hand differences radial club hand, 396-398 syndactyly, 394-396 Consolidation phase of explicit memory, 108 Constraint-induced (CI) movement therapy definition of, 461 description of, 263 research and case studies on, 444-446 Constructional skills, 461 Contoured drawing, 220, 461 Cooperation and self-dressing, 205t Coordination development of, 45, 46f eye-hand and reaching, 89-97 force in grasping and lifting, 55-56 during grasping, 48-51 by infants when reaching, 93 Corpus callosum, 176, 177-179 Corticospinal tract connections to alpha motor neurons, 4-5 Culture and hand skill development, 121-122 and handedness, 176-177 and handwriting, 226-227 and self-care skill development, 196-197 Cursive writing kinesthetic approach to teaching, 335-336 motor patterns in, 3 teaching, 328-329 D Decision making concerning hand actions, 102 Deep pressure and joint approximation, 351 Denver Handwriting Analysis, 304t-305t Development process of, 102-103 stages of object manipulation, 143, 144-146, 144b theories for hand and motor skills, 117-121 Developmental coordination disorder (DCD) affecting sensorimotor control in hands, 54-58 efficacy and research studies, 447, 448t, 449 impaired hand function with, 54-58 self-care skill difficulties in, 194-195 Developmental disabled children reaching skills impaired in, 96-97 self-care skill difficulties in, 194-195 Developmental Gerstmann syndrome and haptic perception, 81-82 Developmental Test of Visual Motor Integration (VMI), 325, 448-449 Dexterity and bead stringing, 273-275 diagram illustrating, 58f glossary definition of, 461 of hands and function, 374-375 Differentiation, 106, 108 Digital cleavage embryonic development of, 21-22
468 • Index Digital interphalangeal joints, 26f, 27 Digital pronate grasp, 281f Digits anatomical diagram of, 22f description and position of, 22-23 embryonic development of, 21-22 fractures and dislocations of, 383-384 ligaments of, 23, 24f, 25, 26f muscles and tendons of, 33-34, 36f Disabilities affecting drawing abilities, 225 and keyboarding, 232 Disk grip, 461 Dissociation, 461 Distal finger control practice sheet for, 339f Distal grips, 335b Distal phalanges anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Distal transverse arch anatomical diagram of, 23f description of, 22 Diversity; See culture Dorsal interossei muscles, 32-34, 35f Dorsal stream, 104-105, 461 Down syndrome affecting drawing abilities, 225 affecting grip force, 11 and haptic perception, 80-81 reaching skills affected by, 96 Drawing; See also graphomotor skills and computers, 224-225 definition of, 217 development in preschoolers, 280-284 and developmental evaluation, 225-226 instruction and practice, 229-232 motor learning theories, 218 nature of, 220-221, 222f, 223-224 and pencil grasp, 282-283 phases of, 221, 222f role of vision and kinesthesis in, 218-219 tools, 280-281 Dressing skills antecedents of, 203, 205t with fasteners, 208, 209t, 210 learning and hand skill development, 203, 205t, 206, 207t, 208, 209t, 210 order of difficulty, 208b undressing, 206t without fasteners, 206, 207t Drinking, 199, 200t Dual motor systems, 461 Dynamic grasp, 280-281 Dynamic muscle tone, 461 Dynamic splinting, 408, 461 Dynamic tone, 461 Dynamic tripod grip, 210-220, 462 Dyspraxia and haptic perception, 81-82 E Earedness, 181 Eating, 199, 200t, 201, 202t, 203, 204t
Ecological approach to cognition and motor skill development, 103 Edema description of, 375 management of burn, 391-392 sandwich splints for, 391f Edinburgh Handedness Inventory (EHI) description of, 170-171 reliability of, 170t Elbows casting and splinting, 380f, 381f embryonic development of, 21-22 Encoding phase of explicit memory, 108 End range of movement, 462 Episodic memory, 107-108 Epithelization, 368-369, 370b Ergonomics affecting handwriting, 298t, 301, 306 Ethnicity; See culture Evaluation Tool of Children’s Handwriting (ETCH), 302t303t, 316-317 Evaluations of hand injuries activities of daily living, 376 hand dexterity, 374-375 hand sensibilities, 376 hand strength, 373-374 interview and history, 370 pain, 375-376 range of motion, 370-375 wound, edema and scarring, 375 of handwriting actual performance, 300-301, 302t-305t, 306 fine motor skill, 296-297 gross motor skill, 295-296 keyboarding performance, 306-307 motor performance, 294-295 neuromuscular and neurodevelopmental status, 293 pre-evaluation data collection, 292 related performance components, 292-300 visual motor control, 297-298 visual perception components, 293-294 of haptic perception in infants and children, 77-78 Executive function of the hand, 462 Explicit memory, 107, 462 Exploration and haptic perception, 69-74 by infants, 73b movements used in object, 144-147 and object dimensions, 71t Extensor lag, 462 Extensor pollicis muscles of hand, 31-35, 32f Extensor tendons injuries to, 388-389 Extrinsic muscles and tendons of hands, 27, 28f-29f, 29-31, 32f Eyedness, 181 Eye-hand coordination definition of, 462 interventions to improve, 242-243 play activities to improve, 273-275 and reaching, 89-97
Index • 469 F Face pain scale-revised (FPS-R) to measure pain, 376 Facilitation case study techniques of, 352, 357t, 362t definition of, 350 techniques of, 350-351 Fasteners, 208, 209t, 210 Feedback, 462 Feed-forward controlled movements, 47 Feeding; See self-feeding Fibroblastic stage of wound healing, 369 Fine motor coordination, 462 Fine motor skills activities that help children learn, 285b case study on preschoolers, 285-286 emphasis on in different cultures, 121-122 evaluating handwriting, 296-297, 298t goals for preschoolers, 267-268 and handwriting instruction, 230-231 instruments to assess, 296t learning on vertical surfaces, 268-269 planning, 278 problems in children, 239-262 and visual perceptual inventory for preschoolers, 290-291 Finger feeding, 199, 200t Finger plays, 289 Fingers; See also digits; phalanges biomechanics of flexor pulley system, 38f embryonic development of, 21-22 force coordination in, 55-56 fractures and dislocations of, 383-384 and in-hand manipulation skills, 255-260 isolation activities, 275 movements of, 4-5 in older children, 157-158 sensory function, 7-9 and tactile system, 48-54 and vision and object manipulation, 147-148, 149f Fisted hands problems with, 250 splinting for, 406t Fixing, 462 Flexor pollicis muscles, 31-34, 33f, 35f Flexor tendons injuries to, 385-388 splinting, 417-418 Food; See also self-feeding and learning to self-feed, 199, 200t, 201, 202t, 203, 204t serving and preparing, 203, 204t Footedness, 181 Force coordination in grasping and lifting, 55-56 Forearms embryonic development of, 21-22 muscles of, 31f nerves associated with tendons and muscles of, 28f-29f, 31f, 32f, 33f, 37-40 power of muscles in, 37, 38t “Fractionate,” 4, 16
Fractures of fingers, 383-384 splinting for, 417 of wrist, 380-383 Friction of objects and anticipatory control, 53 Friedrich and Baumel casts, 388f Full arm casts, 380f Functional range of motion, 370-371, 372f, 375 G Gamekeeper’s thumb, 383-384 Gender and haptic perception, 67 and self-care skills, 197 Geoboards, 272, 275 Gestation, 21-22 Glossary, 461-464 Graphesthesia test (GRA), 78 Graphomotor skills; See also drawing; handwriting acquisition of, 217-220 motor learning, 218 definition of, 217, 462 development of, 217-233 drawing, 220-226 grasping and manipulating tools, 219-220 handwriting, 226-232 role of vision and kinesthesis in, 218-219 ergonomic factors, 298t, 301, 306, 320 writing implements, 220 Grasp; See also grip and anticipatory control, 53 basic coordination of forces during, 48-51 case scenario concerning, 101-102 developmental sequence of birth through 24 months, 138t-139t experiments involving, 48-51 illustration of normal, 42f importance of postural control in, 346 by infants systems that influence, 122-126 interventions for problems with, 249-251 mass, 5 and object manipulation in infants and children, 143-158 and osseous arches, 23 power functional patterns of, 41-43 precision, 41-43 preparation and vision, 11-13, 16 in preschoolers for drawing/ writing, 280-281 primitive and transitional, 127-128 purposeful, 128-130 radial finger patterns, 251-253 role of somatosensory cortex in, 10-11 sample short-term goals for, 244, 245b of scissors, 279 and self-dressing, 205t and sensorimotor control, 53-54 and sensory feedback, 16 strength and “Strong Hands,” 273, 274b
470 • Index Grasp (Continued) and tripod grips, 219-220 variability in, 155-157 Grasp phase definition of, 462 of reaching, 90-91 Grip; See also grasp affecting handwriting, 298t, 301, 306 assessment systems, 297 in children with cerebral palsy, 11 definition of, 462 force development, 51 interventions for problems with, 249-251 power description of, 41 functional patterns of, 41-43 precision functional patterns of, 41-43 precision versus power, 4-5 and preshaping hand, 12-14 role of somatosensory cortex in, 10-11 tripod, 219-220 Grip force coordination of, 55-56 definition of, 462 development of, 51 and friction, 53 illustration of, 50f illustration of rates of, 56f Grooming developing self-care skills in, 210, 211t, 212t Gross motor skills emphasis on in different cultures, 121-122 evaluation of for handwriting analysis, 295-296 Grouping, 106, 108 H Hamate anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Hammering, 42f, 171b, 172 Hand muscles; See also muscles direct corticospinal connections to alpha motor neurons, 4-5 and the primary motor cortex, 5 Hand performance definition of, 162 versus hand preference, 162, 163f, 164-165 skill and ability tests for, 171-172 Hand preference; See also handedness definition of, 162, 462 four components of, 164 versus hand performance, 162, 163f, 164-165 linked to immature grips, 220 in preschoolers, 281-282 tests for, 170-171 Hand skills complementary two-hand use, 152-153 development of importance of posture and senses in, 122-126 and infant play, 117-137, 138t-139t
Hand skills (Continued) functional in infants, 120-121 grasp, release and bimanual development birth through 24 months, 138t-139t learning stages, 120-121 object manipulation, 143-158 and the primary motor cortex, 5-7 problems in children goal setting, 243-244, 245b impact on occupational performance, 239-240 intervention approaches, 240-241 intervention planning factors, 241-243 intervention strategies, 244-262 research, 244 splints, casts and constraints, 262-263 and self-care, 193-214 Hand strength in infants, 375 measuring of, 289 in middle childhood to adolescence, 374 Hand therapy pediatric, 367-398 congenital problems, 394-398 evaluation of, 369-376, 377t-379t introduction to, 367-368 phases of wound healing, 368-369, 370b thermal injuries, 389-394 traumatic injury treatment, 376, 380-394 Handedness categories of, 165-166, 166b in children assessment of, 170-172 classification of, 165-168 definition of, 161, 162, 163f, 164 development of, 177-179 factors influencing, 172-177 flow chart illustrating, 163f introduction to, 161-162 left and switch, 168-169 and pediatric occupational therapy, 179-184 prevalence of, 169-170 consistency of, 167-168 definition of, 462 development of from 2 years to age 6, 179 from birth to 24 months, 177-178 and drawing, 223-224 and haptic perception, 67-68 intervention theories for left, 182-184 for switched, 182 for unestablished, 180-182 in preschoolers, 281-282 theories concerning establishment of genetic, 173-174 intrauterine influences, 174-176 neuroanatomical and neurophysical, 172-173 pathologic, 174-176 sociocultural and environmental, 176-177 Handedness profile charts, 180f, 183b Hand-eye coordination; See eye-hand coordination Hand-object interactions cortical control of, 3-17 skills in prerequisites for, 3-4
Index • 471 Hands anatomy and kinesiology of, 22-43 clumsiness or impaired function of in children, 54-58 diagram illustrating bones of, 22f embryonic development of, 21-22 extrinsic muscles and tendons of, 27, 28f-29f, 29-31, 32f functional patterns of, 41-43 isolated movements of, 247-249 joints and ligaments of, 23-27 movements of sensory function, 7-9 summary and therapeutic implications, 16 muscles and tendons of, 27, 28f-29f, 29-37 nerves associated with, 28f-29f, 31f, 32f, 33f, 37-40 osseous structures of, 22-23 perceptual functions of, 63-83 (See also haptic perception) power of muscles in, 37, 38t preference (See handedness) preshaping of, 12-14, 16 role of inferior parietal lobe in, 12-13 research studies on effects of cerebral palsy, 436t-440t sensation and anticipatory control in, 346-349 sensibility of, 376 skin and subcutaneous fascia, 40, 41f systems that contribute to abilities of, 46f Handwriting consequences of bad, 291 definition of, 217, 462 development in preschoolers, 280-284 developmental progression of, 226-229 diagram illustrating skilled, 218f ergonomic factors, 298t, 301 evaluation of actual performance, 300-301, 302t-305t, 306 fine motor skill, 296-297 gross motor skill, 295-296 keyboarding performance, 306-307 motor performance, 294-295 neuromuscular and neurodevelopmental status, 293 pre-evaluation data collection, 292 related performance components, 292-300 visual motor control, 297-298 visual perception components, 293-294 handedness actions involved in, 182-183 implement grasp and manipulation, 219-220 instruction and practice, 229-232 interventions to improve efficacy studies on, 451, 452t-453t, 454-456 kinesthetic approach to teaching, 335-340 learning on vertical surfaces, 268-269 legibility of, 226-228, 300-301 tests for assessing, 302t-305t, 311-318 manipulatives program before learning, 270-278 motor learning theories, 218 performance factors, 229-232 prosthetic devices, 331, 332f quality of, 227-228 reported mean speed, 228t role of vision and kinesthesis in, 218-219 and skilled tool use, 14-16 speed of, 226-228, 301 tests for assessing, 302t-305t, 311-318 teaching principles and practices, 319-342
Handwriting (Continued) bilateral integration, 326-327 kenesthetic approach to, 335-341 kinesthesia, 328-330 pencil grip, 330-331, 332f, 333-335 spatial analysis, 327-328 training groups, 319 upper extremity support, 320-321 visual control, 324-325 wrist and hand development, 321-324 tests for assessing, 302t-305t, 311-318 versus writing, 226 writing tools, 220 Handwriting Speed Test, 304t-305t, 317-318 Haptic perception accuracy, 67 definition of, 63-64, 462 development in children, 65-67 development in infants, 64-65 disorders of, 79-80 evaluation of in infants and children, 77-78 functions contributing to, 68-77 manual manipulation and exploration in adults, 70-71 in children, 73-74 in infants, 71-73 strategies, 69-74 and recognizing objects and shapes, 65-67 role of somatosensory sensation in, 69 summary and implications for practice, 67-68, 82 of texture, size and weight, 66 visual, 65-66 Healing phases of wound, 368-369, 370b Hemiplegic cerebral palsy coupled movements with, 97 High load brief stress (HLBS), 419 Holding skills bilateral, 133 Hygiene developing self-care skills in, 210, 211t, 212t Hypertonia versus hypotonia, 349 Hypotonia versus hypertonia, 349 I Ilizarov, 396 Imaginary play, 125 Implicit memory, 107, 462 Independence in self-care skills cultural and social factors, 196-197 and disabilities, 194-195 importance to children, 194 maturation and motivation, 197-198 motor factors, 198 sex difference, 197 Independent activities of daily living (IADLs) and self-care, 193-214 Index finger embryonic development of, 21-22 grip force rates, 56f splints, 416f
472 • Index Index grip, 333, 334f Infants bimanual skills in, 131-134 contexts of learning, 121-122 development of reaching skills, 92-95 hand skill development in contexts for, 121-122 in play context, 117-137, 127-137, 138t-139t systems that contribute to, 122-127 theories of, 117-121 haptic manipulation strategies in, 71-73, 76-77 haptic perception development in, 64-65 learning skills in, 108-110 measuring pain in, 375-376 neonatal splints, 415-417 object manipulation stages of, 143, 144-150, 144b object release in, 130-131, 136-137 play activities 12-24 months, 134-136 birth to 12 months, 127-129 and posture, 122-124 preterm haptic perception disorders in, 79-80 reaching movements by, 94-95 role of vision and cognition in haptic perception, 74-76 sensory progression in, 124-126 Inferior parietal cortex and tool use, 14-16 “use-dependent” organization of, 14 Inferior parietal lobes diagram illustrating, 13f functions of and hand movements, 12-13 role in preshaping of hand, 12-13 Inferior pincer grasp, 462 Inflammation clinical signs and implications of, 368-369 stage of, 368 In-hand manipulation assessment of, 297 definition of, 150, 462 five basic types of, 255b general principles for developing, 256-260 important factors influencing, 156-157 intervention strategies, 255-260 sample short-term goals for, 244, 245b sequence of difficulty, 256-257 and “Smart Hands” activities, 273 studies of, 154-155 Inhibition case study techniques of, 352, 357t, 362t definition of, 349 techniques of, 350 Intermodal perception, 462 Interpretive phase of drawing, 221, 222f Interventions for cerebral palsy neurodevelopmental treatment (NDT), 353-354 to enhance hand function efficacy of, 433-457 grasp levels, 251-253 for hand skill problems in children
Interventions (Continued) goal setting, 243-244, 245b impact on occupational performance, 239-240 intervention approaches, 240-241 intervention planning factors, 241-243 intervention strategies, 244-262 research, 244 splints, casts and constraints, 262-263 for handedness, 180-184 to improve handwriting efficacy studies on, 451, 452t-453t, 454 muscle tone and posture, 247 positioning, 246 surgical and medical, 446-447 typical problem areas, 245b Intraparietal sulcus diagram illustrating, 13f Intrathecal baclofen, 446-447 Intrinsic hand muscles and alpha motor neurons, 4-5 and tendons, 31-35 J Joint capsules, 25, 26f Joints deep pressure, 351 embryonic development of, 21-22 metacarpophalangeal, 23, 25, 26-28 of phalanges, 23, 24f, 25, 26f stability and mobility and hand function, 277 Juvenile arthritis splinting, 418 K Key points of control with cerebral palsy, 350 in neurodevelopmental treatment (NDT), 349, 353-354 Keyboarding, 232, 306-307 Kinesiology of the hand, 21-43 Kinesthesia definition of, 219, 462 and proprioception, 48 role in graphomotor skills, 218-219 and teaching handwriting, 230-231, 328-330, 329b, 335-340 Kinesthetic Sensitivity Test (KST), 219, 231 Kinesthetic teaching techniques, 335-340 Kleinert splints, 385, 386f Knickerbocker’s test, 171b, 172 Knowledge components of, 106-107 and memory, 107 L Lacing activities, 273-275 Language disorders and haptic perception, 81-82 Lateral tripod grasp, 462 Learned movements description of, 47 Learned non-use, 462
Index • 473 Learning definition of process of, 102, 108-110 descriptions of, 109b dressing skills, 203, 205t, 206, 207t, 208, 209t, 210 and sensorimotor control, 53-54 stages of in infants, 120-121 to write name, 283b Learning disabilities and haptic perception, 81-82 Left handedness consistent versus inconsistent, 168 definition of, 166b intervention theories for, 182-184 Letters presenting models for, 339-340 Lifting and anticipatory control, 53 coordination of forces during, 48-51 performed at different ages, 50f Ligaments checkrein, 27 collateral, 25, 26f of digital joints, 25, 26f splinting, 383 of wrist, 23, 24f Limb position sense and proprioception, 48 Load force illustration of, 50f illustration of rates of, 56f Loading phase and manipulation force development, 51 Longitudinal arch anatomical diagram of, 23f description of, 22 Low load prolonged stress (LLPS), 419 Lunate anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f M Mallet finger, 384 Manipulation; See also in-hand manipulation; object manipulation and anticipatory control, 52-53 bilateral, 260-262 complexity of, 101 definition of, 144, 147 examples of strategies of by children, 74b force development, 51 general principles for developing in-hand, 256-260 grip and finger and self-care, 213 important aspects of, 102 by infants systems that influence, 122-126 in-hand intervention strategies, 255-260 versus prehension, 150 during preschool training, 270-278 role of in haptic perception in, 69-70 and sensorimotor control, 53-54
Manipulation (Continued) “Strong Hands” and “Smart Hands,” 272-278 and tripod grips, 219-220 Manual Form Perception (MFP) test, 77-78 Manuscript writing versus cursive, 324-326 kinesthetic approach to teaching, 335-336 Mastery motivation, 197-198 Mastication, 47 Matin Vigorimeter, 289 Maturation stage of wound healing, 369 Mechanoreceptors and touch, 48 Meissner corpuscles, 48 Memory definition of, 107, 462 storing information in, 102 working and handwriting performance, 229 Mental retardation; See also Down syndrome and haptic perception, 80-81 Metacarpals anatomical diagram of, 22f description and position of, 22-23 embryonic development of, 21-22 ligaments of, 23, 24f Metacarpophalangeal joints, 23, 25, 26-28 collateral ligaments of, 25f, 26 Middle phalanges anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Miller Assessment for Preschoolers, 77 Minnesota Handwriting Assessment (MHA), 302t-303t, 306, 311-312 Mirror movements, 462 Mixed handers definition of, 166b Mobility versus stability, 241 Motivation and hand ability in children, 46f to improve hand skills, 45-46 and interests of children to learn, 242-243 mastery, 197-198 Motor control summary of, 58-59 Motor impairments affecting drawing abilities, 225 affecting reaching skills, 96 Motor learning definition of, 347, 463 development of in infant play context, 117-137, 138t-139t and kinesthetic teaching techniques, 335-340 role of somatosensory cortex in, 11-12 theory of, 242 Motor programs definition of, 47 Motor skills affected by brain injuries, 81 and cognition adaptation, 102 attention and perception, 104-105
474 • Index Motor skills (Continued) case scenario, 101-102 concept formation, 106-107 importance in acquisition of, 102-103 memory, 107-108 perceptual-motor processes, 105-106 processes of, 103-108 definition of, 102 development of versus cognitive skill development, 110 in infant play context, 117-137, 138t-139t role of somatosensory cortex in, 11-12 variability in, 155-157 and evaluating handwriting, 294-295 goal setting interventions, 243-244, 245b important aspects of, 102 and kinesthetic teaching techniques, 335-340 repetition and practice, 242 and self-care, 193-214 Mouth two hands and exploration with, 145f used for object exploration, 146, 147-149 Movements acceleration and deceleration phases of, 93-95 and anticipatory control, 53 components of, 102 constraint-induced (CI) therapy description of, 263 research and case studies on, 444-446 control theories, 46-47 development of in small children, 51 disorders of cerebral palsy, 344 goal directed, 102 in infants and hand skill development, 117-121 isolated hand and arm, 247-249 learned description of, 47 mature reaching integration of sensory information, 92 role of proprioception, 91-92 role of vision in, 91 speed, 89-90 transport and grasp phase, 90-91 reaching beginning stage, 92-93 coordinating body parts, 93 development during infancy, 92-95 planning, 93-95 sensory information, 95 variations, 95 summary of object manipulation, 148-149 theories of, 102-103 units, 463 used in object exploration, 144-146 Multimodal exploration definition of, 64, 463 Muscle tone assessment of in cerebral palsy patients, 352 definition of, 349 neurodevelopmental approach to, 347 case study, 360-363
Muscles balance and biomechanical considerations, 35, 37 embryonic development of, 21-22 extrinsic of hands and arms, 27, 28f-29f, 29-31, 32f and hand ability in children, 46f intrinsic of hands, 31-35 and proprioception, 48 tendon movement with, 37 weakness with cerebral palsy, 344 work capacity of, 37, 38t Myelomeningocele (MMC) affecting drawing abilities, 225 affecting reaching movements, 96 N Needle threading, 323, 324f Neonatal infants haptic perception disorders in, 79-80 splints, 415-417 Neoprene thumb abduction splints, 334f, 335 Neovascularization, 368-369, 370b Nerves associated with tendons and muscles of hand, wrist and forearm, 28f-29f, 31f, 32f, 33f injuries to splinting approach, 418, 423-425 supply of to forearm, hand, and wrist, 37-40 Neurodevelopmental Treatment Association (NDTA), 344-347 Neurodevelopmental treatment (NDT) for cerebral palsy, 343-363 case studies, 355-359, 360-363 efficacy of, 354-355 research studies on, 440-443 facilitation techniques, 350-351 inhibition, 349-350 intervention process for cerebral palsy, 353 key points of control, 349, 353-354 planning treatment, 352, 357t, 361t and postural control, 347-346 role of sensation and anticipatory control in, 346-349 Neuromaturation model of motor development, 117-118 Newborns; See infants Newton Early Childhood Program, 267, 280, 283, 285-286, 289, 290-291 Nine-Hole Peg test, 297 Non-language learning disabilities (NLD), 327-328 Numeric rating scale (NRS) to measure pain, 376 O Object manipulation; See also manipulation and anticipatory control, 346-349 and haptic perception, 69-74 in infants and children, 143-158 of multiple objects, 148 in older children, 157-158 in preschool and early childhood years, 154-157
Index • 475 Object manipulation (Continued) role of vision in infant, 147-148 during toddler years, 150-154 summary of, 153-156 Object release from 12 to 24 months, 136-137 from birth to 12 months, 130-131 control of by toddlers, 152 developmental sequence of birth through 24 months, 138t-139t Objects characteristics of and grasp interventions, 250-251 familiar versus unfamiliar, 56-57 and hand interaction cortical control of, 3-17 handling of multiple, 148 infant exploration actions, 73b in-hand manipulation of, 256-260 manipulation (See also object manipulation) and exploration, 144-147 and haptic perception, 69-74 in infants and children, 143-158 release of (See also object release) in infants, 130-131, 136-137 spatial orientation of, 67 substance, structure and function of, 71t transporting, 251 weight, size and friction of and anticipatory control, 52-53 Observation of Visual Motor Orientation and Efficiency, 325 Occupational therapy approaches to handwriting efficacy research on, 454-456 approaches with preschoolers research studies, 449-450, 451t, 453-454 cerebral palsy research, 436t-440t effective sessions for preschoolers, 284-285 fine motor program for preschoolers, 267-287, 289-291 goal setting, 243-244, 245b interventions to enhance hand function, 433-457 for hand skill problems, 239-264 pediatric and handedness, 179-184 role of performance when treating cerebral palsy, 347 Opponens pollicis muscles, 31-34, 33f, 35f Osseous arches of the hands, 22, 23f P Pacini corpuscles, 48 Pain with cerebral palsy, 344 with fractures in wrists, 380-383 of hand wounds, 375-376 measurement tools, 376 Palmar aponeurosis, 40, 41f Palmar grasps, 128-130, 256-258, 463 Palmar interossei muscles, 32-34, 35f Parietal cortex and hand-object interactions, 3-4
Passive range of motion (PROM), 370, 371f, 375 Pathologic handedness definition of, 166b, 463 Peabody Developmental Fine Motor Scales, 3, 150, 243 Pediatric Evaluation of Disability Inventory (PEDI), 195-196, 197, 199 Pencil grips improper, 319 remediation, 331, 333f training, 330-335 “Pencil Pal,” 331, 333f Perception definition of, 104, 463 definition of process, 102 and hand ability in children, 46f importance in hand skill development, 119-120 in motor skills, 104-105 and self-care, 214 Perceptual skills; See perception Perceptual-motor processes, 105-106, 463 Peripheral nerves injuries to splinting approach, 418, 423-425 Personality factors in self-care, 214 Pervasive Developmental Disorder- Not Otherwise Specified (PDD-NOS), 278 Phagocytosis, 368-369, 370b Phalanges; See also digits; fingers embryonic development of, 21-22 fractures and dislocations of, 383-384 joints of, 23, 24f, 25, 26f Physical health functional definition of, 193 Piagetian approach to cognition and motor skill development, 103 Pincer grasps, 463 Pisiform anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Play activities and child motivation, 242-243 and fine motor development, 267-268 imaginary or symbolic, 125 in infants from 12 to 24 months, 134-136 from birth to 12 months, 127-129 for preschoolers, 271-272 “Smart Hands,” 272-278 “Strong Hands,” 273, 274b therapy research on efficacy of, 449 Play dough, 273, 278f Positioning and grip force, 50f of hand during burn healing phase, 391, 393 and self-care, 213 and splinting, 403-404 using vertical surfaces, 268-269 Posterior parietal lobes importance for hand-object interactions, 3-4 two parts of, 13 Postural control, 463
476 • Index Postural sway, 346 Posture affected by cerebral palsy, 344 affecting handwriting, 298t, 301, 306 anticipatory, 346 and hand skill difficulties, 247 and handwriting instruction, 230-231 importance of in infant hand skill development, 122-124 in reaching, 93 inhibition and facilitation techniques, 349-351 and kinesthetic teaching techniques, 338, 341f reflex-inhibiting, 344-347 relationship to upper extremity function and cerebral palsy, 347-346 Power and hand preference, 164 Power grip definition of, 463 description of, 41 development of, 253-254 Praxis, 463 Precision grip alteration with object sizes, 41f definition of, 463 development of, 143 normal and impaired development of force control in, 45-59 versus power grip, 4-5 types of, 43f Precision handling definition of, 463 and handwriting, 323, 324f Preference; See hand preference; handedness Prehensile force control in children with central nervous system disorders, 45-46 sensory information used for, 57-58 Prehension skills from 12 to 24 months, 136 from birth to 12 months, 127-130 definition of, 463 patterns of versus manipulator patterns, 150 Premotor cortex and hand-object interactions, 3-4 Preschoolers; See also children fine motor program for, 267-287, 289-291 fine motor skills in and visual perceptual inventory, 290-291 object manipulation in, 154-157 occupational therapy research studies, 449-450, 451t, 453454 scissors skills in, 279-280 Primary motor cortex diagram of, 5f role in hand movements, 5-7 summary and therapeutic implications, 16 “use-dependent” organization of, 5-7 Primary sensory cortex connections to, 16, 17f Primary somatosensory cortex; See somatosensory cortex Priming definition of, 104 Primitive grasps, 128-130 Primitive wound contracture, 368-369, 370b Production Consistency Sheet, 329, 330f
Pronation interventions to improve, 247-249 splints, 414 Proprioception definition of, 463 description of, 48 role in reaching, 91-92 Proprioceptive systems influencing hand skill development in infants, 124-126 Prosthetic devices for handwriting, 331, 332f Proximal interphalangeal (PIP) joints description of, 23 dorsal dislocation of, 384 Proximal phalanges anatomical diagram of, 22f description and position of, 22-23 embryonic development of, 21-22 ligaments of, 23, 24f Proximal to distal development, 241 Proximal transverse arch anatomical diagram of, 23f description of, 22 Purposeful release, 131 Puzzles, 276 Q Quadrupodgrasp, 280-281 R Radial digital grasp, 251-253, 463 Radial nerve palsy case study on splinting, 423-425 Radial palmar grasp, 463 Radial-ulnar dissociation, 253, 463 Range of motion (ROM) assessment of in cerebral palsy patients, 352 in children and adolescents, 375 of hands following wounds or injuries, 370-375 in infants, 372 neurodevelopmental approach to, 347 in toddlers, 372-373 types of, 370-373 upper extremity and handwriting, 321, 324 “Rapper snappers,” 271 Reaching and anticipatory control, 53, 94 case scenario concerning, 101-102 definition of, 89 and eye-hand coordination, 89-97 and hand preference, 164 importance of postural control in, 346 in infancy, 143 and motor impairments adaptations, 96-97 in children, 96-97 with hemiplegic cerebral palsy, 97 planning and feedback control, 96
Index • 477 Reaching (Continued) movements beginning stage, 92-93 coordinating body parts, 93 development during infancy, 92-95 integration of sensory information, 92 planning, 93-95 role of proprioception, 91-92 role of vision in, 91 sensory information, 95 speed, 89-90 transport and grasp phase, 90-91 variations, 95 and self-dressing, 205t two main parts of, 12 Reflexes control theories concerning, 46 Reflex-inhibiting postures (RIPs), 344-345 Regeneration of tissue wounds, 368 Release; See object release Repair of tissue wounds, 368 Representation definition of process, 102 Research evidence on cerebral palsy, 435, 436t-440t on hand function in cerebral palsy patients, 436t-440t on in-hand manipulation, 154-155 levels of, 433-434 summary of, 456-457 Retrieval phase of explicit memory, 108 Reverse transverse grip, 463 Right handedness consistent versus inconsistent, 168 definition of, 166b Rotation skills, 257-259, 323, 324f, 463 S Sandwich splints, 391f Scaphoid anatomical diagram of, 22f description and position of, 22-23 fractures, 380-383 ligaments of, 23, 24f Scar remodeling stage of wound healing, 369, 370b Scars management of burn, 391-393 from radial club hand operations, 396-398 sandwich splints for, 391f from syndactyly operations, 394-396 Scissors illustration of cutting, 153f motor functions of, 323 skill development in preschoolers, 279-280 Scissors grasp, 463 Selective attention, 104 Selective posterior rhizotomy, 446 Self-care skills acquisition of, 196-198 mastery motivation, 197-198
Self-care skills (Continued) maturation, 197 motor factors, 198 sex differences, 197 social and cultural issues, 197-198 chronology of acquisition activities of daily living, 212-214 cognitive and personality factors, 214 dressing and undressing, 203, 205t, 206, 207t, 208, 209t, 210 eating and drinking, 199, 200t hand skills in, 193-214, 213-214 hygiene and grooming, 210, 211t-212t self-feeding, 199, 200t serving and preparing food, 203, 204t utensil use, 201, 202t, 203b definition of, 463 development of, 196-210, 211t-212t, 213-214 and fingers, hands and grip abilities, 213-214 and hand skill development, 193-214 independence in in children, 194, 212-213 in the disabled, 194-195 measurement of nonstandardized measures, 195 standardized measures, 195-196 perceptual factors in, 214 Self-dressing; See dressing skills Self-feeding, 199, 200t, 201, 202t, 203, 204t Semantic memory, 107-108 Sensorimotor control organization of, 53-54 Sensorimotor cortex firing of haptic neurons in, 69 and hand-object interactions, 3-4 Sensorimotor system delay problems research studies on, 450t and hand ability in children, 46f Sensory awareness versus motor control, 241-242 typical activities for, 247b Sensory feedback and grasp, 16 and haptic perception, 69 importance of in motor learning, 11-12 Sensory information and development of reaching skills, 95 gathered by hands and fingers, 7-9 and hand skill development in infants, 119-120 integration of vision and proprioception, 92 processing and handwriting, 299-300 and reaching, 92 used for force control, 57-58 Sensory Integration and Praxis Tests (SIPT), 77-78, 179-180 Sensory systems impairments with cerebral palsy, 346-347 importance of in infant hand skill development, 124-126 Shift skills, 259, 463
478 • Index Shoes learning to tie, 209t, 210 and haptic perception, 63 Size haptic perception of, 66 of objects and anticipatory control, 52 Skier’s thumb, 383-384 Skilled hand movements; See also movements role of sensory information in, 8-9 Skilled tasks versus unskilled, 164 Skills acquisition of, 108-110 definition of, 108 Skin of hands, 40, 41f “Smart Hands,” 272-278 Social isolation with cerebral palsy, 344 Somatosensory cortex circuit of, 17f and hand skills, 7-9 and hand-object interactions, 3-4 illustration of, 10f role in grasp, 10-11 role in motor learning, 11-12 role in sensory function, 7-9 “use-dependent” organization within, 9-10 Somatosensory sensation role in haptic perception, 69 Somatosensory system cortical organization of, 8-9 definition of, 463 feedback and graphomotor skills, 218-219 S.O.S. grids, 282 Southern California Sensory Integration Tests (SCSIT), 179180 Spasticity with cerebral palsy, 344 biomechanics of, 350-349 definition of, 464 neurodevelopmental approach to, 345-346 surgical and medical interventions, 446-447 Spatial analysis in handwriting, 327-328 Spina bifida affecting drawing abilities, 225 Spinal cord ventral horn divisions of, 4-5 Splinting; See also splints anti-Houdini techniques, 420b, 418f-420f, 419 benefits of, 402-403 case study on radial nerve palsy, 423-425 common problems requiring finger control, 414-415, 416f fisted hand, 411-412 neonatal intensive care, 415-417 supination and pronation, 414 thumb in palm, 411 weight bearing, 414, 415f wrist flexion, 412-413 wrist ulnar and radial deviation, 413-414 efficacy of research studies on, 443-444
Splinting (Continued) fabrication for children, 410 history of, 401-402 as intervention adjunct, 262-263 material characteristics, 409-410 for orthopedic problems, 407t, 417-419 patient care instructions, 429-430 principles of, 402-403 selection of, 404, 405f, 406t-407t, 408-410 types of, 404, 405f, 406t-407t, 408 Splints; See also splinting finger and thumb, 383-384 Kleinert, 385, 386f for mallet finger, 384f neoprene, 334f, 335, 382f for tendon injuries, 385-389 vendors, 431 wearing schedules and precautions, 419 for wrist and elbow injuries, 380-382 Squeeze grasp, 464 Stability affecting handwriting, 298t, 301, 306 definition of, 464 and grasp, 250 importance of wrist in handwriting, 321-323 of materials and grasp, 259f, 260-262 versus mobility, 241 and self-dressing, 205t Stabilization; See stability Static splinting, 404, 464 Static tripod grasp, 464 Stereognosis, 464 Stickers, 276 Stiffness, 464 Storage phase of explicit memory, 108 Stringing activities, 273-275 “Strong Hands,” 272 Subcutaneous fascia of hands, 40, 41f Superior parietal lobes diagram illustrating, 13f effect of lesions in, 8f functions of and hand movements, 12-13 Supination interventions to improve, 247-249, 251 splints, 414 Swallowing and movements, 47 Swan neck deformities splinting, 418f Switched handedness definition of, 166b, 464 intervention theories for, 182 problems associated with, 169b theories concerning, 168-169 Symbolic play, 125 Syndactyly, 394-396 T Tactile apraxia, 15 Tactile cues, 351
Index • 479 Tactile perception and brain injury, 81 impairments and learning disabilities, 81-82 Tactile scanning, 63 Tactile system awareness or discrimination, 246-247 definition of, 48 and friction, 53 identifying properties, 71b importance of in grasping and holding, 48-54 influencing hand skill development in infants, 124-126 and motor control, 241-242 and object recognition, 69 Tapping, 171b, 172, 351, 464 Teaching approaches to handwriting efficacy studies, 451, 452t-453t, 454 principles and practices of handwriting, 319-342 bilateral integration, 326-327 kinesthetic approach to, 335-341 kinesthesia, 328-330 pencil grip, 330-331, 332f, 333-335 spatial analysis, 327-328 training groups, 319 upper extremity support, 320-321 visual control, 324-325 wrist and hand development, 321-324 to write name, 283b Tendons balance and biomechanical considerations, 35, 37 extrinsic of hands and arms, 27, 28f-29f, 29-31, 32f injuries to hand, 385-389 and intrinsic muscles of hands, 31-35 movement with muscle contraction, 37 and proprioception, 48 Tensile strength and wound healing, 369 Test of Handwriting Skills (THS), 302t-303t, 312-313 Test of Legible Handwriting, 304t-305t Test of Motor Impairment (TOMI), 231, 448-449 Tests for assessing handwriting, 302t-305t Texture haptic perception of, 66 identifying, 71b The Development Test of Visual-Motor Integration, 227b The Luria-Nebraska Neuropsychological Battery, 78 Therapeutic interventions; See interventions Thermal hand injuries in children classification of severity, 392-394, 390t closed wound scarring phase of, 392-394 open wound phase of, 390-392 patterns of, 389-390 “Think breaks,” 339f Three-jaw chuck, 464 Threshold tests, 464 Thumb in palm, 406t, 411 Thumb spica splints, 382f Thumb-index web space, 322
Thumbs embryonic development of, 21-22 grip force rates, 56f metacarpophalangeal joint of, 26-27 Ties, 208, 209t, 210 Tissue burn scarring of, 391-394 regeneration of wounds, 368 Toddlers; See also children complementary two-hand use by, 152-153 measuring pain in, 375-376 object manipulation by, 150-154 summary and therapeutic implications of object manipulation skills, 153-156 Toileting, 210, 211t Tone; See muscle tone Tools definition of, 198 features of skilled use of, 14-16 handwriting, 220 history of, 319 power grasps on, 253-254 role of inferior parietal cortex in use of, 14-16 and self-care activities, 198-210, 211t-212t skills with and hand preference, 164 stabilization of hand structures needed for, 333b Total end range time (TERT), 419, 464 Touch; See also tactile system importance of in grasping and holding, 48 Toys “Smart Hand,” 272-278 types of for fine motor skill development, 271-278 Tracing, 171b, 172, 282 Trajectory definition of, 89 of reaching, 91 Translation, 464 Transport phase of reaching, 90-91, 464 Trapezium anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Trapezoid anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Tripod grip adapted, 331f description of, 219-220 illustration of, 269f, 280f training children in, 330-331 Triquetrum anatomical diagram of, 22f description and position of, 22-23 ligaments of, 23, 24f Trunk functions of kinesiologic aspects of, 347-350 stability of and self-dressing, 205t
480 • Index U Unestablished handedness definition of, 166b intervention theories for, 180-182 Upper extremities casting research on efficacy of, 443-444 constraint therapy, 263 embryonic development of, 21-22 interventions for cerebral palsy a neurodevelopmental treatment approach, 343-363 motor development tests, 195 splinting, 401-419, 420f-422f case study, 423-425 and teaching handwriting, 320-321 and voluntary release, 254 Upper limbs biomechanical interactions of in cerebral palsy patients 350-349 functions of kinesiologic aspects of, 347-350 “Use-dependent” organization of inferior parietal and ventral premotor cortex, 14 within somatosensory cortex, 9-10 Utensils; See also tools learning progression for using, 201, 202t, 203b V Vasoconstriction, 368-369, 370b Vasodilation, 368-369, 370b Velocity illustration of rates of, 56f Ventral premotor cortex diagram illustrating, 13f role in preshaping hand, 13-14 “use-dependent” organization of, 14 Ventral stream, 104, 464 Verbal rating scale (VRS) to measure pain, 376 Vertical surfaces examples of activities for, 269b materials and suppliers, 289 teaching hand/wrist positions using, 268-269 Vestibular input, 351 Vibration, 144-145, 350, 353 Vision and grasp preparation, 12-13, 16 influencing hand skill development in infants, 119-120, 124-126 and manuscript versus cursive writing, 324-326 problems with cerebral palsy, 344 role of in graphomotor skills, 218-219 in haptic perception, 65-67, 74-75, 77 in object manipulation, 147-148 in reaching, 91 Visual analog scale (VAS) to measure pain, 376 Visual motor control evaluation of, 297-298 in handwriting, 324-326
Visual motor integration (VMI), 227, 231, 325, 448-449, 451, 452t-453t, 454 Visual perceptual inventory and fine motor skills for preschoolers, 290-291 Visual-motor skills instruments to assess, 296t Visual-perceptual skills evaluation of, 293-294 instruments to assess, 295t Volition, 464 Voluntary release definition of, 464 difficulties intervention strategies, 254-255 sample short-term goals for, 244, 245b W “Wake Up Hands,” 271-272 Wee Functional Independence Measure (WeeFim), 195-196 Weight bearing splints, 414 on upper and lower limbs, 351 haptic perception of, 66 of objects and anticipatory control, 52 shifting, 351, 464 Wind-up toys, 276 Work capacity of muscles, 37, 38t Working memory, 229, 464 Wounds burns classification of severity, 392-394, 390t closed wound scarring phase of, 392-394 open wound phase of, 390-392 patterns of, 389-390 caused by congenital differences, 394-398 characteristics of, 375 phases of healing, 368-369, 370b Wrists embryonic development of, 21-22 fractures in, 380-383 joints of, 23, 24f nerves associated with tendons and muscles of, 28f-29f, 31f, 32f, 33f, 37-40 stabilizing of importance for handwriting, 321-322 supination and stability of, 251 and teaching handwriting, 321-324 ulnar and radial deviation, 413-414 using vertical surfaces when training, 268-269 Writing; See graphomotor skills; handwriting Written language assessments, 298-299 Z Zippers, 208, 209t, 210 Zone of proximal development, 240-241, 243, 464 Zoo sticks, 276
