Evidence from Event-Related Potentials

This study focuses on the time course of the integration of ambiguous words (e.g., BANK) into a higher order mental representation of the preced ing sentence context in Broca's aphasics with comprehension deficits. Recent evidence suggests that Broca's aphasics are unable to access the infrequent meaning of ambiguous words (Swinney, Zurif, & Nicol, 1989; Prather, Love, Finkel, & Zurif, 1994). Swinney et al. (1989) showed that these patients, in contrast to normal control subjects and W ernicke's apha sics, had faster reaction times (RTs) only to target words that were related to the most frequent meaning of ambiguous words. This was true even when the preceding sentence context biased the alternative, less frequent, meaning. They concluded from this study that Broca's aphasics either fail to exhaus tively access word meanings, or alternatively, that in these patients “ the lexical module operates on a slower-than-normal rise time." In contrast, however, based on studies that varied the interval of silence between the ambieuous and target words, Haeoort, Brown, and Swaa