Electrophysiological responses to argument structure violations in healthy adults and individuals with agrammatic aphasia

► An ERP acceptability judgment experiment was run with aphasic and control subjects. ► Semantic violations elicited an N400 effect in young and older controls. ► Argument structure violations elicited a biphasic N400-P600 pattern in controls. ► Aphasics exhibited a reduced, delayed N400 in response to semantic violations. ► Aphasics did not show normal biphasic responses to argument structure violations.