Profound developmental dyscalculia: evidence for a cardinal/ordinal skills acquisition device.

This article presents an analysis of a form of dysfunctional mathematical development. A child of normal intelligence was unable to acquire basic cardinal numerical skills, despite relatively intact ordinal number use. These findings provide evidence for an innate "cardinal/ordinal skills acquisition device" (COSAD). It is argued that if this COSAD is lacking, ordinal number use may be compensated for by linguistic logic and visual skills. Cardinal number skills, however, remain limited as these demand an innate internal representation of quantity, which cannot be compensated for. The findings are discussed in terms of different approaches to number development.

Disruption of automatic speech following a right basal ganglia lesion.

Following a right basal ganglia lesion, a right-handed man, age 75, was unable to recite familiar verses. Serial automatic speech, singing, recitation of rhymes, and swearing were impaired, and only idioms and social greetings were preserved. Speech no longer contained overused phrases and he could comprehend automatic speech. In contrast, propositional speech was preserved in both French and Hebrew. Right basal ganglia lesions may impair production but not comprehension of automatic speech.