Verb-argument structure processing in complex sentences in Broca's and Wernicke's aphasia.

We describe three experiments that explore the real-time access of verb-argument structures in a group of normal control subjects, a group of Broca's aphasic patients, and a group of Wernicke's aphasic patients. Specifically, we examine whether our subjects exhaustively access the thematic representations of verbs in active, passive, cleft-subject, and cleft-object sentences. We find that our normal control subjects and Broca's aphasic patients are sensitive to the thematic properties of verbs, regardless of sentence type. Our Wernicke's aphasic patients do not show on-line sensitivity to this lexical property. We discuss these results in terms of multiple resources dedicated to specific sentence processing devices, a possible semantic deficit in Wernicke's aphasia, and a double-dissociation between the operation of accessing a verb's thematic properties and the operation of computing the trace-antecedent relation.