Grammatical Deficits in Aphasia

Abstract

The procedural distinction between open-class and closed-class words allows one to predict that a positional level deficit should selectively disrupt the production of grammatical morphemes in sentence production, but not as isolated words. Very different, and often contrasting, hypotheses were invoked to interpret grammatical disorders in aphasia. The cases discussed so far demonstrate that a positional-level deficit may result in a difficulty in producing grammatical morphemes in sentences. Neuropsychological observations show that a cerebral lesion may selectively disrupt thematic role assignment, sparing the production of grammatical morphemes. Difficulties of comprehension of grammatical structures have been hypothesised to result from phonological short-term memory deficits. Traditionally, disorders of grammatical comprehension were attributed to an impairment of grammatical morpheme processing. The scientific literature has described two clinical syndromes characterised by the presence of a grammatical deficit; agrammatism and paragrammatism.