Numerical and arithmetical deficits in learning-disabled children: Relation to dyscalculia and dyslexia

Cognitive research on the number, counting, and arithmetic competencies of children with a learning disability in arithmetic (AD) is reviewed, and sim ilarities between the associated deficits of AD children and the deficits o f individuals afflicted with dyscalculia are highlighted. It is concluded t hat the defining features of AD and most dyscalculias are difficulties with the procedural features associated with the solving of complex arithmetic problems and difficulties in remembering basic arithmetic facts. The proced ural deficits and one form of retrieval deficit appear to be associated wit h functioning of the prefrontal cortex, while a second form of retrieval de ficit appears to be associated with the functioning of the left parieto-occ ipito-temporal areas and several subcortical structures. The review ends wi th a discussion of the potential relation between this second form of retri eval deficit and dyslexia.