are not necessary but commonly co-occur within the population. Because the three disorders central to this book are cast as syndromes, this issue of whether these disorders are syndromes, collections of symptoms, or arbitrary groups could be systematically evaluated.
This type of work would also help establish the nature of cognitive processes characterizing these populations. As Denckla (chapter 13 of this volume) notes, the boundary between spatial cognition and executive functions is poorly established in the behavioral domain. Similarly, is attention a separable process or better subsumed under the rubric of executive function? For spatial cognition, major connections occur between the right posterior area of the brain and the frontal lobes. Similarly, as Courchesne et al. (chapter 6, this volume) notes, higher order mental activities mediated by the neocerebellum are richly connected to motor output and planning areas of the frontal lobes. Consistent with Goldman-Rakic (chapter 1 of this volume), behavioral dissociations may not reflect the nature and location of a CNS insult, but the effect on a complex set of sequenced events leading to an end product.
Classification also offers a general perspective for this research. The articles in this volume are not isolated studies, but occur in a broader research context. Questions about relationships across syndromes may lead to a set of principles concerning the relationship of behavior and the brain. It is not likely that a set of findings characteristic of children with Williams or Turner syndrome will only apply to these disorders. Rather, these findings may reflect more fundamental principles concerning how the brain mediates behavior after early disruption. It is the search for these principles that holds the keys to enhancing the development of children with early CNS deviations.
Supported in part by National Institutes of Health Grants NS25368, Neurobehavioral Development of Hydrocephalic Children, HD27597, Neuropsychological Sequelae of Pediatric Head Injury, and NS21889, Neurobehavioral Outcome of Head Injury in Children.
Alajouanine T. H., & Lhermitte F. ( 1965). "Acquired aphasia in children". Brain, 88, 653-662.
Aram D. M. ( 1990). "Brain lesions in children: Implications for developmental language disorders". In J. F. Miller (Ed.), Research on child language disorders. A decade of progress (pp. 309-320). Boston: College Hill Press.