Child Neuropsychology

Concepts, Theory, and Practice

Jonathan Reed, Jody Warner-Rogers, Jonathan Reed, Jody Warner-Rogers

• Publisher: Wiley-Blackwell
• Year: 2011
• Print ISBN: 9781405152662
• eBook ISBN: 9781444357189
• Edition: 1
• Topic: Psychology
• Subtopic: Cognitive Psychology & Cognition
• Index: Psychology

Child Neuropsychology

"Reed and Warner-Rogers have made a substantial contribution to the development of child neuropsychology, which has suffered a dearth of comprehensive texts, in this broad-ranging, well-conceived, and authoritative volume."
Professor J Graham Beaumont, Department of Clinical Psychology, Royal Hospital for Neuro-disability, London

"For me, they have more than succeeded in meeting their goals for combining science and practice, staying academically grounded but accessible, and powerfully presenting the case for the necessary focus on developmental variables. The text is both fascinating and readable throughout."
Jane Holmes Bernstein, Department of Psychiatry, Children's Hospital Boston / Harvard Medical School

"A valuable addition to the libraries of pediatric/child neuropsychologists. It takes a somewhat different and refreshing approach as compared to existing texts, focusing on neurobehavioral functions rather than clinical disorders.The book places a strong emphasis on clinical translation and application that should appeal to practitioners, but is firmly grounded in state-of-the-art theory and research."
Professor Keith Yeates, Department of Pediatrics, Children's Research Institute, Ohio State University

"Here in a single volume, the reader will find summaries of current theory and knowledge regarding nearly all of the most common disorders seen by pediatric neuropsychologists. Whether read as the textbook for a course, or bought as a self-study aid, those new to the field will find this information to be invaluable. More experienced professionals are sure to appreciate well-edited chapters that will quickly bring them 'up to speed' on recent advances. This is an immensely useful book that should be a part of every pediatric neuropsychologist's library."
Steve Hughes, PhD, LP, ABPdN, Director of Education and Research, The TOVA Company

Based on the most up-to-date research, Child Neuropsychology is a thorough and accessible guide to the key concepts and basic processes central to neuropsychological assessment and child evaluation. Essays by leading experts in the field cover basic neuropsychological functions and related disorders in the context of brain development.

Divided into three parts, the text begins with clear definitions of the concepts and methodology of brain development in child neuropsychology. Part two examines normal and abnormal functional development. The final part considers professional practice and provides valuable insights into the special problems of neuropsychological assessment of infants and children in clinical and educational settings.

1

Introduction

Jonathan Reed and Jody Warner-Rogers

If “child neuropsychology is the study of brain-behaviour relationships within the dynamic context of the developing brain” (Anderson, 2001, p. 3), then in order to understand the field and practice within it, one must possess a thorough understanding of what a brain does and how it develops. The process of change is key in child neuropsychology. This differs from adult neuropsychology, where the focus of study is on damage to an already developed brain. Robust models of adult brain–behavior relationships have developed over the past hundred years. Child neuropsychology is, in contrast, an emerging discipline. It requires the creation of new models based on the process of development. We need to understand how brains and behavior develop, what contributions genes make, and what happens when there are deviations from typical development. Many people from different backgrounds, including researchers in child development, neuroscientists, and clinicians, are developing their understanding of these processes. We felt that there was a need to bring together different voices to begin to define what a comprehensive theory of child neuropsychology should encompass.

The idea for this book came from our experiences as clinicians. As practicing neuropsychologists, we recognized that a clear formulation is the key to understanding and supporting children’s brain-based difficulties. For children, a neuropsychologically informed formulation requires a thorough understanding of how brain–behavior relationships develop over time (see Chapter 21). But how does one acquire this understanding? We realized that something was missing from our bookshelf, and it was at this point that the idea for the book began to materialize. By their very nature, textbooks can date very quickly, particularly in a fast-moving field. They can never reflect the most contemporary research findings; one must hit the journals for that level of recency. Yet textbooks can provide the conceptual framework within which newly acquired knowledge can be organized, understood, and integrated. This textbook aims to provide that architecture for child neuropsychology. We saw the need for a book that bridged cutting-edge science and clinical practice, a book that was developmentally focused and not disorder based, a book that was academically grounded, but accessible to a range of students, clinicians, and researchers. We hope that this textbook addresses this need.

The first part of the book looks at key theoretical concepts and research evidence that underpins our current understanding of brain development and function. Dagmara Annaz, Annette Karmiloff-Smith, and Michael C. S. Thomas operationalize the term “developmental approach” by stressing the need to trace normal developmental trajectories. Hans J. ten Donkelaar describes basic brain development from conception onward, and discusses the influence of specific aberrations that occur throughout this process, each capable of producing a wide range of deviations from the expected trajectories. Yulia Kovas and Robert Plomin discuss the contribution of genes in relation to learning disability and provide insight into the possible impact of genes on neuropsychological development. Judy S. Reilly and colleagues outline the fallout of early traumatic brain injury, highlighting the concept and constraints of neural plasticity. Brain imaging has brought forward our understanding of brain-behavior relationships, and Paramala J. Santosh and Ruksana Ahmed provide a helpful review of the technologies of brain imaging and their use with children. One key concept that is often missing from neuropsychology textbooks is that of general intellectual ability (IQ). Mike Anderson explores the concept of IQ and how this broad-based marker of brain functioning may develop.

Undoubtedly, a firm grounding in “normal” child neuropsychological development is the foundation for any efforts to evaluate and (most importantly) to improve those situations in which developmental progress has not proceeded smoothly. The field of child neuropsychology relies heavily on the theories and research of developmental and cognitive psychologists. Part II of the book gives an overview of current research regarding normal neuropsychological development and provides examples of deviations from these processes. Within the domain of cognitive development, Frederic Dick and colleagues take us through the emergence of language skills and the effect of different disorders on language development. Janette Atkinson and Marko Nardini look at visuospatial and visuomotor development; Arthur MacNeill Horton and Henry Soper outline the key factors that are important in understanding the development of memory; Maxine Sinclair and Eric Taylor discuss the development of attention; and Claire Hughes and Andrew Graham examine the development of executive function. But neuropsychological development is not confined to basic information processes: social, behavioral, and emotional development are key factors in clinical practice. Rebecca M. Todd and Marc D. Lewis provide a fascinating discussion of the development of the self-regulation of emotions and behavior. Simon Baron-Cohen and Bhismadev Chakrabarti review the state of our understanding in social neuroscience and, in particular, how empathy develops. No discussion of normal development would be complete without reference to education. The last two chapters of Part II are devoted to the development of academic skills: Usha Goswami summarizes the acquisition of reading, and Brian Butterworth provides insight into the often neglected areas of numeracy and dyscalculia.

Building on the first two parts of the book, Part III focuses on clinical practice. Ingram Wright and Peta Sharples discuss neuropsychological practice with neurological disorders. Ian Frampton illustrates the applicability of neuropsychological thinking to child and adolescent mental health issues. Sue Harrison and Jane Hood highlight the value of neuropsychological assessment in education. Sarah Helps demonstrates how the field can contribute to the understanding and management of other physical illnesses. The book concludes with an approach to neuropsychological assessment and formulation, based on the themes of this book and on our clinical experiences.

We hope that this book will enhance the clinical practice of our colleagues, and help to stimulate ideas and discussion for the next stage of research and practice within the exciting field of child neuropsychology.

Reference

Anderson, V., Northam, E., Hendy, J., & Wrennall, J. (2001). Developmental neuropsychology: A clinical approach. Hove, East Sussex: Psychology Press.

Part I

Key Concepts

2

The Importance of Tracing Developmental Trajectories for Clinical Child Neuropsychology

Dagmara Annaz, Annette Karmiloff-Smith, and Michael C. S. Thomas

Children change. Despite the truism of this statement, the dynamics of developmental change are frequently absent from studies of child disorders. Why is this? We believe that the reason lies in the strong influence of adult neuropsychology, in which researchers and clinicians focus on brains that have developed normally and become consolidated by adulthood prior to the brain insult. Since the adult brain is highly specialized, it is unsurprising that models of adult brain function focus on special purpose, independently functioning modules, whose components could be damaged or left intact by a specific brain trauma: the metaphor of boxes in the brain to be crossed through when damaged. While the adult framework can be informative about the end-state of development, it is inappropriate for understanding developmental disorders or even typical development because it ignores the dynamics of developmental change (Karmiloff-Smith, 1997, 1998). Indeed, the start-state of development is very different from the adult end-state.

The normal infant cortex is initially highly interconnected (Huttenlocher & Dabholkar, 1997; Neville, 2006), and it is only with time and with the processing of different kinds of inputs that the child brain becomes increasingly specialized and localized for function (Johnson, 2001). In other words, the brain does not start out with independently functioning modules: Modules are emergent from a gradual and complex process of modularization (Karmiloff-Smith, 1992). This means that a tiny impairment early on in, say, the developing visual system might have cascading effects on the subsequent acquisition of, say, number or vocabulary. Such impairments may or may not be compensated for, depending on the severity and the specialization of the impairment in question. It also means that one cannot take a single snapshot of, say, middle childhood, describe the phenotype of a developmental disorder, and from that suggest an intervention program. This would not only be clinically imprecise for a given child, but likely to be inappropriate for the syndrome in general. In our view, to assist clinical diagnosis and subsequent intervention, it is crucial to ascertain how the current phenotype originated at the beginning of a developmental trajectory, as well as knowing where it will lead in the future of that developmental trajectory.

This chapter will therefore concentrate on the importance of tracing and tracking full developmental trajectories, as well as focusing on associations between domains and between syndromes, rather than the current focus on dissociations. For illustrative purposes, we will concentrate mainly on autism spectrum disorder (ASD), Down syndrome (DS), fragile-X syndrome (FXS), and Williams syndrome (WS).

Prenatal Learning

Fetal development starts very early, at the onset of zygote formation, with the first neurons of the human forebrain present at a very early stage (Bystron, Rakic, Molnár, & Blakemore, 2006). Moreover, for the cognitive neuroscientist, learning also starts very early. From about the seventh month of pregnancy onward, the healthy fetus is actively processing various forms of auditory input (Hepper, 1995; Moore, 2002). Fetuses who hear a specific piece of music in the womb will discriminate that particular music from other pieces at birth. Newborns also recognize their mother’s voice at birth, despite the fact that in the womb it was filtered through the amniotic fluid and sounds very different ex utero. Yet, during intrauterine life the fetus forms some abstract representation of mother’s voice and is able to distinguish her voice from other female voices at birth (Kisilevsky et al., 2003).

Furthermore, fetuses also learn the beginnings of the speech patterns of their mother tongue while in the womb. Research using acoustic spectroscopy has shown that, at 27 weeks, a fetus’s cry already contains some features of his or her mother’s speech, such as rhythms and voice characteristics. Also, DeCasper and colleagues showed that fetuses at 33–37 weeks’ gestation demonstrated memory of children’s rhyme, while still in the womb, in response to mothers repeatedly reading a certain rhyme to their unborn baby (DeCasper, Lecaunet, Busnel, Granier-Deferre, & Maugeais, 1994).

For the moment, we lack any knowledge about the learning capacities of the atypically developing fetus. However, for a truly full understanding of the developmental trajectory of a child with a disorder, this is where we should in the future be grounding our field of enquiry. For the time being, we must begin with postnatal development.

Neuroconstructivism and Postnatal Learning

From the moment the child is born, he or she is bombarded with interesting stimuli—faces, voices, objects, and so forth—and, as a result of the repeated processing of these different stimuli, the infant brain becomes slowly but increasingly specialized (Johnson, 2001). Elsewhere, we have argued that a middle way is needed between staunch nativism, on the one hand, in which the infant brain is thought to be prespecified for each of its modular abilities, and behaviorism, on the other, in which a single, general purpose learning mechanism is invoked. Neuroconstructivism, an intermediate way between nativism and behaviorism, holds that a small number of domain-relevant learning algorithms jump-start the infant brain (Elman et al., 1996). Initially, all algorithms attempt to process all inputs, but with time the one that is most domain-relevant (say, to rapid sequential processing) wins out in the competition between algorithms and becomes domain-specific over developmental time (Karmiloff-Smith, 1998). We speculate that this is the case for the typically developing infant. However, we do not know whether the atypically developing infant brain displays the same level of interconnectivity early on, and whether subsequent pruning leads to specialization and localization of function in children with developmental disorders. But, theoretically, we can already ask what the implications of early interconnectivity would be for the atypically developing brain.

Within the theoretical assumptions of neuroconstructivism, the interconnectivity of early cortical development means that a tiny deficit could permeate all parts of the cortex. But, given the interaction between different algorithms and different structures in the environmental input, some parts of the brain would be more seriously affected by the deficit than others. This could give rise, over developmental time, to a seemingly isolated domain-specific impairment and the apparent preservation of other domains (i.e., scores “in the normal range”). In other words, what seems in the end-state to be a domain-specific deficit may have originated in the start-state as a more domain-general deficit (Annaz & Karmiloff-Smith, 2005; Karmiloff-Smith, 1997, 1998; Karmiloff-Smith et al., 2004). We therefore strongly advocate the importance of investigating not only domains of weaknesses, but also domains in which individuals show proficiency; that is, reach scores comparable to controls. Indeed, if changes to domain-relevant properties are initially widespread, and some properties are less relevant to a given domain, then that domain might exhibit lesser, more subtle impairments (Karmiloff-Smith, 1998; Karmiloff-Smith, Scerif, & Ansari, 2003). Ideally, then, an explanation of developmental deficits consists in identifying how these initial domain relevancies have been altered in the disorder, and then how the subsequent process of emergent modularization has been perturbed.

“Spared” versus “Impaired” Processing?

In the literature on developmental disorders, one frequently encounters terms such as “spared,” “intact,” and “preserved” when describing atypical development (e.g., Hoffman, Landau, & Pagani, 2003; Rouse, Donnelly, Hadwin, & Brown, 2004; Tager-Flusberg, Plesa-Skwerer, Faja, & Joseph, 2003). The notion of a selective deficit implies the impairment of a single process or domain together with the preservation (i.e., normal development and functioning across time) of others. When a brain has developed normally, resulting over time in specialized, localized functions, it is possible that after consolidation subsequent brain injury may produce selective damage(s) while other components continue to operate normally. Hence, it might be appropriate to consider them as spared, intact, or preserved.

However, in the case of a developmental disorder of genetic origin, the use of such terms is questionable. They imply that the purported intact function has developed normally from infancy, through childhood to adulthood, with no interactions with other developing parts of the brain. Yet, as we mentioned above, the infant brain starts out highly interconnected (Neville, 2006), so it is unlikely that one part of the brain can develop normally in total isolation, without being affected (even subtly) by other parts of the atypically developing brain. The use by clinicians of the intact-impaired dichotomy in characterizing developmental aspects of functioning has problematic implications for intervention (A = intact, no intervention required; B = impaired, intervention required). Such dichotomies, then, could actually hinder rather than enhance the study of the dynamics of atypical development. By contrast, if one considers development as a dynamic process of interactions and competition, it could be, for instance, that training in rapid sequential movements in the assumed “preserved” motor system could impact another nonmotor domain which is impaired, rather than direct training in that nonmotor domain.

Concrete Examples from Developmental Cognitive Neuroscience

Studies that have taken the neuroconstructivist developmental approach to behavioral phenotypes have shown, for instance, that areas of purported relative strength at one stage of development (middle childhood or adolescence) were not necessarily stronger at earlier stages of development (Paterson, Brown, Gsödl, Johnson, & Karmiloff-Smith, 1999). For example, Paterson and colleagues (1999) showed that infant cognitive profiles in Williams syndrome and Down syndrome cannot be predicted from the adult end-state pattern of their cognitive functioning. One of the most compelling examples is vocabulary learning in toddlers with Williams syndrome, which is very poor and as delayed as vocabulary acquisition in toddlers with Down syndrome. By contrast, when individuals with Williams syndrome reach adolescence or adulthood, their language vastly outstrips that of their counterparts with Down syndrome. The same differences between the infant start-state and the adult end-state exist for number (Paterson et al., 1999; Paterson, Girelli, Butterworth, & Karmiloff-Smith, 2006). Infants and toddlers with Williams syndrome are sensitive to differences in small numbers, whereas those with Down syndrome perform even more poorly than younger mental age-matched infant controls. By contrast, in adulthood, scores for Down syndrome in the number domain outstrip those for Williams syndrome (Paterson et al., 2006). This highlights the importance of examining an entire developmental trajectory rather than a snapshot of development in childhood or adulthood.

Another example comes from studies of children with unusual genetic mutations. We have for several years been examining the cognitive phenotypes of children with deletions within the Williams syndrome critical region but which are smaller than the typical Williams syndrome deletion on chromosome 7 (Karmiloff-Smith et al., 2003; Tassabehji et al., 1999). Our aim is to delineate the functions of various genes in expressing the full Williams syndrome phenotype. Here again, developmental trajectories have played a crucial role. In the case of one partial deletion child (HR), we found on initial testing that she did not differ from normal controls on the Bayley Scales of Infant Development. We could have concluded that the genes deleted in her case played no role in the Williams syndrome phenotype. However, as we began to trace her trajectory over developmental time, we found that, although she had a milder phenotype, she none the less progressively approximated the Williams syndrome phenotype and drew away from the typical trajectory. This was true at both the level of facial dysmorphology (Hammond et al., 2005) and that of her cognitive phenotype (Karmiloff-Smith, 2004). Figure 2.1 provides an illustration of this changing pattern.

Another example from developmental cognitive neuroscience is provided by Scerif and colleagues (2004) who investigated visual search in toddlers with fragile-X syndrome and those with Williams syndrome. These researchers demonstrated how important it is to go beyond mere scores to examine patterns of errors. While both groups of atypically developing toddlers reached a similar overall level compared to mental age-matched controls, their pattern of errors was very different. Toddlers with Williams syndrome made the highest number of erroneous touches on distractors. They were more affected than the other groups by the combination of larger display size and target-distractor similarity (conjointly increasing the perceptual load of the search task). By contrast, the toddlers with fragile-X syndrome made more errors of perseverance to targets already visited. In other words, where performance scores did not distinguish between the two syndromes, their respective patterns of erro...

Table of contents

• Cover
• Praise for Child Neuropsychology
• Title page
• copyright
• Dedication
• List of Illustrations
• Notes on Contributors
• Acknowledgments
• CHAPTER 1: Introduction
• Part I
• Part II
• Part III
• Plates
• Index