Effects of nonlinguistic auditory variations on lexical processing in Broca's aphasics.

In a series of experiments, the effect of white noise distortion and talker variation on lexical access in normal and Broca's aphasic participants was examined using an auditory lexical decision paradigm. Masking the prime stimulus in white noise resulted in reduced semantic priming for both groups, indicating that lexical access is degraded by nonlinguistic white noise distortion. However, talker variation within a prime-target pair had no effect upon the performance of either the normal or aphasic individuals. The absence of a talker variation effect suggests that voice-specific information is not encoded in the lexical representations of words. The normal performance of Broca's aphasics under conditions of both white noise and talker variation supports the view that these patients have a lexical processing impairment rather than a more generalized language deficit characterized by limited computational resources.