Electrophysiological manifestations of open- and closed-class words in patients with Broca's aphasia with agrammatic comprehension - An event-relatedbrain potential study

This paper presents electrophysiological data on the on-line processing of open- and closed-class words in patients with Broca's aphasia with agrammat ic comprehension. Event-related brain potentials were recorded from the sca lp when Broca patients and non-aphasic control subjects were visually prese nted with a story in which the words appeared one at a time on the screen. Separate waveforms were computed for open- and closed-class words. The non- aphasic control subjects showed clear differences between the processing of open- and closed-class words in an early (210-375 ms) and a late (400-700 ms) time-window. The early electrophysiological differences reflect the fir st manifestation of the availability of word-category information from the mental lexicon. The late differences presumably relate to post-lexical sema ntic and syntactic processing. In contrast to the control subjects, the Bro ca patients showed no early vocabulary class effect and only a limited late effect. The results suggest that an important factor in the agrammatic com prehension deficit of Broca's aphasics is a delayed and/or incomplete avail ability of word-class information.