Learning-disabled brains: a review of the literature.

In this paper, we review the literature investigating the neurophysiological correlates of learning disabilities (LD). The focus is placed on the developmental presentations of LD and not on learning difficulties that arise as a result of some form of acquired neurological insult. Following a brief historical overview of research in this area, we examine evidence from investigations of brain morphology and of functional brain systems in individuals with LD. The studies reviewed include those that have employed postmortem examinations, neuroimaging techniques, or electrophysiological procedures. We summarize the major morphological and functional distinctions between individuals with LD and nonimpaired individuals. Finally, we make recommendations for future studies in this area, including the adoption of more widespread methodological conventions, and a greater consideration of nosological/classification and developmental issues.