Neurobiological correlates of learning disorders.

An anatomic pattern of (1) temporal lobe symmetry and (2) left more than right frontosylvian cortical anomalies has been documented in a small number of children with developmental disorders of reading. These alterations occur during embryogenesis and are the direct result of neither genetic factors nor perinatal stress. Underperformance in reading, writing, and other linguistic skills as well as visuo-spatial excellence may result from these changes. Related brain mechanisms may influence disorders affecting attention, arithmetic, and nonverbal learning. The suspected association between depressed mood and certain learning disorders raises the possibility of joint cause. Future work in learning disorders must define affective state precisely, specifically characterize learning disorder, and wisely apply technology to reveal anatomic, physiological, and metabolic correlates.