Simulation of aphasic naming performance in non-brain-damaged adults.

Discussion abounds in the literature as to whether aphasia is a deficit of linguistic competence or linguistic performance and, if it is a performance deficit, what are its precise mechanisms. Considerable evidence suggests that alteration of nonlinguistic factors can affect language performance in aphasia, a finding that raises questions about the modularity of language and the purity of linguistic mechanisms underlying the putative language deficits in persons with aphasia. This study investigated whether temporal stress plus additional cognitive demands placed on non-brain-damaged adults would produce aphasic-like performance on a picture naming task. Two groups of non-brain-damaged participants completed a picture naming task with additional cognitive demands (use of low frequency words and making semantic judgments about the stimuli). A control group performed this task at their own pace, and an experimental group was placed under time constraints. Naming errors were identified and coded by error type. Errors made by individuals with aphasia from a previous study (S. E. Kohn and H. Goodglass, 1985) were recoded with the coding system used in the present study and were then compared with the types of errors produced by the 2 non-brain-damaged groups. Results generally support the hypothesis that the language performance deficits seen in persons with aphasia exist on a continuum with the language performance of non-brain-damaged individuals. Some error type differences between groups warrant further investigation.