The general goal of the proposed research is to determine the appropriate structural and processing characterization of the language deficit in Broca's aphasia. The research is particularly concerned with the characterization of that deficit as primarily syntactic and not lexical, and with the claim that the syntactic deficit represents a competence loss (i.e., a general loss of the relevant linguistic information) as opposed to impairment of a specific """"""""performance"""""""" system. To achieve this goal, the proposed research addresses the following specific questions: (1) To what degree are syntactic subcategorization features of verbs available to Broca's aphasics in tasks that minimize processing load and time constraint?; (2) To what degree are syntactic subcategorization features of nouns available to Broca's aphasics in tasks that minimize processing load and time constraint?; (3) To what extent is the use of syntactic subcategorization information for verbs and nouns differentially affected by the time and processing constraints of real-time language processing?; (4) Are differences in the preservation or availability of lexical subcategorization features predictable from correlated semantic distinctions?; (5) To what degree is knowledge of lexical subcategorization features related to agrammatic production?; (6) To what degree is a loss of such lexical information related to agrammatic comprehension, when it occurs? A group of Broca's aphasics and two groups of control subjects (neurologically intact subjects and patients with focal lesions in the dominant hemisphere, but with no agrammatism, e.g., anomics) will be presented with sentences in which there is a systematic variation of lexical subcategorization features. The features selected for testing sample a range of different structural features, and include both semantically and syntactically relevant subcategorization features. The same sentence types will be presented to subjects in three different tasks, contrasted in their processing requirements. Modality of performance is also varied to permit control of certain correlated variables (viz., prosody). A comprehension measure is also included to determine the degree of covariation in patients' agrammatic comprehension and their knowledge of lexical subcategorization features. By providing a precise characterization of the syntactic deficit in Broca's aphasia, the proposed research will contribute to our understanding of the neurological substrates of language, as well as to remediation of its deficits.
