Canonical structure without access to verbs?

Abstract

Agrammatic sentence production in aphasia has been connected to disturbances of verbs and the role played by verbs in determining the structural expression of thematic roles assumed by other words in the sentence. Apparently contradictory data are presented from an aphasic patient, who had difficulties in retrieving verbs in spite of a relatively well preserved use of canonical structure in written sentence production, where he frequently left a blank or dash between agent and theme to signal that a word was missing. A therapy study is reported where the focus was on differentiating verb meanings and integrating verbs in sentence production. After therapy the patient showed significant improvement in verb production, but only for trained items. He also showed a significant increase in use of canonical sentence structure on trials with trained, but not untrained verbs. It is suggested that the patient was relying on a general schema for canonical sentence structure which may interact with verb-specific knowledge in normal processing.