Anomia in moderate aphasia: problems in accessing the lexical representation.

This study has two objectives: (1) to determine through the analysis of surface manifestations of anomia whether one or several anomic syndromes exist, (2) to identify the psycholinguistic process at fault in anomia with reference to M. F. Garrett's (1982, in A. Ellis (Ed.), Normality and pathology in cognitive functions, London/New York: Academic Press) language production model. Two naming tasks were administered to 24 moderate aphasics. Test A was a standard naming task, and test B was a similar task which included subtests designed to indicate which level of representation was affected whenever patients did not name the target word. The subtests required, respectively, the identification of (a) a conceptual property, (b) two semantic attributes, (c) the first and (d) last syllable of the target word, and (e) the target word itself. Descriptive statistics yielded three groups of subjects different in terms of surface anomic manifestations, yet unrelated to clinical type of aphasia. Moreover, no significant differences between groups emerged on the subtests. All groups showed a good performance on the conceptual and the semantic subtests, suggesting preservation of high-level cognitive and semantic processes. In contrast, subjects evidenced poorer performances in syllabic identification, indicating a disruption of lower level mechanisms which are assumed to retrieve and process formal lexical representations. Results support the view that aphasic anomia originates from a difficulty in accessing the formal lexical representation and not from a semantic problem.