Processing of lexical ambiguities in aphasia.

Wernicke's and Broca's aphasics performed a lexical decision task wherein they had to decide whether the third word of an auditorily presented triplet series of words was "real" or not. The first and third words of each triplet were related to one, both, or neither meaning of the second word which was semantically ambiguous. The performance pattern of the Wernicke's aphasics was similar to that of normals. They showed selective access to different meanings of the ambiguous words, as demonstrated by the fact that the context provided by the first word affected semantic facilitation on the third word. In contrast, Broca's aphasics showed no semantic facilitation in any priming condition. These results are consistent with previous findings, suggesting that semantic representations may be largely spared in Wernicke's aphasics. The failure of the Broca's aphasics to demonstrate facilitation is consistent with the view that they have a processing deficit in automatically accessing the lexical representation of words.