On-line sensitivity to local and long-distance syntactic dependencies in Broca's aphasia.

Seven agrammatic Broca's aphasics and ten normal control subjects performed a word-monitoring task to determine the degree to which violations of syntax would affect word-monitoring performance. Both local and long-distance dependencies were explored, as well as the effects of additional interceding words. Results indicated that normal subjects' word-monitoring latencies were significantly slower to target words in ungrammatical contexts for both local and long-distance dependencies. Aphasic subjects showed a significant sensitivity to ungrammaticality in the local dependency condition; for the long-distance dependencies, however, no reaction time difference emerged between grammatical and ungrammatical stimuli. Results are discussed in relation to current theories of the nature of agrammatic deficits.