A prominent symptom seen in individuals with aphasia due to left cerebral hemisphere disease is difficulty with word retrieval affecting either nouns or verbs. Recent investigation of treatments for word retrieval impairments have been influenced by cognitive neuropsychological models which recognize that word retrieval involves a complex set of lexical processes including semantic and phonologic stages. Subsequently, studies have incorporated restitutive semantic or phonologic treatments and have demonstrative improvements in word retrieval abilities in some individuals, particularly for nouns. Less attention has been given to examining the effects of substitutive word retrieval treatments that might invoke other cognitive processes, no treatment effects for verbs, and to comparing different treatments in the same individuals with aphasia. In our studies, we propose to develop normative data for a battery of lexical tasks assessing comprehension and production of nouns and verbs. We will later administer the battery the battery to patients with aphasia to document the nature of the word retrieval impairments. We then will complete a series of studies in which we contrast two word retrieval treatments. The restitutive treatment will encourage the use of typical semantic and phonologic word retrieval processes, whereas the substitutive verbal+ gestural treatment will encourage the use of pantomimes to evoke a corresponding verbal response. We will compare treatment effects for both nouns and verbs. We will assess performance in structural word retrieval tasks as well as in conversational and functional measures of treatment outcome. In a final experiment, we will study the neural correlates of treatment effects using fMRI.
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