Access to knowledge from pictures but not words in a patient with progressive fluent aphasia

Abstract

We present data from a patient with a progressive fluent aphasia, BA, who exhibited a severe verbal impairment but a relatively preserved access to knowledge from pictures. She exhibited surface dyslexia and dysgraphia and was impaired in the production of the past tense of irregular verbs and the plural form of irregular nouns. She exhibited a mild-moderate impairment in auditory and visual lexical decision tasks that, we argue, was explicable on the basis of a semantic deficit. Knowledge of numbers and body parts was largely preserved even when on tasks involving verbal stimuli. On the basis of this and other evidence, we argue for a distributed, multi-modality system for semantic memory in which information is stored in different brain regions and in different representational formats.