The discrimination of intonational contours in Broca's aphasia.

The observation has been made that agrammatic speakers fail in the comprehension of various sentence types, and this behaviour has been attributed to diminished syntactic capabilities, under the unverified assumption that perception of intonation is intact. Here we re-examine this assumption experimentally with a language, Catalan, which allows for intonation to be the only variable over four sentence types (declaratives, yes-no questions, topicalisations and contrastive focus constructions). We conducted a discrimination task with 10 agrammatic and 10 age- and education-matched control subjects. The subjects were asked to decide whether sentence pairs were identical or not. The overall agrammatic performance was very accurate (89.1% versus 95.6% correct of the controls). The aphasic participants performed above chance in six out of seven conditions. The results indicate that agrammatic individuals succeeded in the task and that their perception of intonation is spared. We conclude that failure in comprehension in agrammatism cannot be attributed to prosodic disruption.