Developmental dyscalculia

Developmental dyscalculia is a specific learning disability affecting the a cquisition of arithmetic skills in an otherwise-normal child. Although poor teaching, environmental deprivation, and low intelligence have been implic ated in the etiology of developmental dyscalculia, current data indicate th at this learning disability is a brain-based disorder with a familial-genet ic predisposition. The neurologic substrate of developmental dyscalculia is thought to involve both hemispheres, particularly the left parietotemporal areas. Developmental dyscalculia is a common cognitive handicap; its preva lence in the school population is about 5-6%, a frequency similar to those of developmental dyslexia and attention-deficit-hyperactivity disorder. Unl ike these, however, it is as common in females as in males. Developmental d yscalculia frequently is encountered in neurologic disorders, examples of w hich include attention-deficit-hyperactivity disorder, developmental langua ge disorder, epilepsy, and fragile X syndrome. The long-term prognosis of d evelopmental dyscalculia is unknown; it appears, however, to persist, at le ast for the short-term, in about half of affected preteen children. The con sequences of developmental dyscalculia and its impact on education, employm ent, and psychologic well-being of affected individuals are unknown. (C) 20 01 by Elsevier Science Inc. All rights reserved.