A modality-specific mapping impairment: spoken versus written production.

A 29 year-old dysphasic woman (AF) presented with superior ability in written over spoken sentences. In contrast, her comprehension showed the reverse trend. Cognitive neuropsychological investigations revealed that her double dissociation was more apparent than real. AF's superior auditory comprehension was attributed to suspected dyslexic factors impeding written comprehension. However, an account of a strong dissociation between her written and spoken production was less obvious. The evidence suggested AF suffered from a procedural mapping deficit which had a disproportionate effect on spoken production. AF's performance challenge current models of lexical access which consider syntactic knowledge to be amodal. An alternative account is considered within Caramazza's (1997) Independent Network model of lexical access.