The description and interpretation of aphasic language disorder.

The nature of aphasic impairment is reviewed from four viewpoints: (1) the construction of behavioural classifications that predict the locus of brain damage; (2) the initial assessment of a range of psycholinguistic functions sufficiently wide to detect the main outlines of deficit and preservation; (3) the elucidation of change in functional status, including both spontaneous and therapy-aided recovery; (4) the relationship between models of normal linguistic performance and the structure of pathological disorder. Arguments are provided against studies of aphasia based upon clinical (or other) taxonomies; arguments are given for the closer integration of analyses of normal and aphasic language.