The retrieval and inflection of verbs in the spontaneous speech of fluent aphasic speakers

Fluent aphasia of the anomic and Wernicke's type is characterized by word retrieval difficulties. However, in fluent aphasic speech, grammatical deviations have been observed as well. There is debate as to whether these grammatical problems are caused by the word retrieval deficit, by an additional grammatical deficit, or by an integration deficit.

Verbs are an interesting word class in this respect, because they are among the words that are hardest to retrieve for many fluent aphasic speakers and some forms require a considerable amount of grammatical computation. For production of a finite lexical verb, the lexical form and inflection for tense and agreement need to be integrated.

In the present study, the use of lexical verbs in finite and non-finite form in the spontaneous speech of 8 Dutch fluent aphasic speakers was analyzed. The results show that retrieval of lexical verbs decreases when more grammatical information needs to be computed. It will be argued that this is best accounted for in terms of an integration deficit: the more computation is needed to express a relation between a verb and intrasentential (agreement) and extrasentential (tense) information, the more difficult it is to retrieve a normal range of lexical verbs. (C) 2010 Elsevier Ltd. All rights reserved.