Electrophysiological manifestations of open- and closed-class words in patients with Broca's aphasia with agrammatic comprehension. An event-related brain 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 agrammatic comprehension. Event-related brain potentials were recorded from the scalp when Broca patients and non-aphasic control subjects were visually presented 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 first manifestation of the availability of word-category information from the mental lexicon. The late differences presumably relate to post-lexical semantic and syntactic processing. In contrast to the control subjects, the Broca patients showed no early vocabulary class effect and only a limited late effect. The results suggest that an important factor in the agrammatic comprehension deficit of Broca's aphasics is a delayed and/or incomplete availability of word-class information.
ter Keurs
M
M
Max Planck Institute for Psycholinguistics and Department of Clinical Neurophysiology, University Hospital Nijmegen, The Netherlands. terkeurs@mpi.nl
Brown
C M
CM
Hagoort
P
P
Stegeman
D F
DF
D000328:Adult; D000368:Aged; D001039:Aphasia, Broca / Q000503:physiopathology*; D016022:Case-Control Studies; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D007807:Language Tests; D008297:Male; D008875:Middle Aged; D012660:Semantics