Syntactic processing in agrammatism: Evidence from lexical decision and grammaticality judgement tasks

Abstract

Abstract This study explored the ability of aphasic patients to process the same sentences varying in syntactic structure in an on-line task (lexical decision) and an off-line task (grammaticality judgement). Eight agrammatic and six age-matched normal subjects were tested on a lexical decision task which probed ten types of ungrammaticalty (five syntactic and five morphological). Normal subjects showed a sensitivity to ungrammaticalty as demonstrated by a significant increase in reaction time to target words in ungrammatical as compared to grammatical contexts. On a grammaticality judgement task using these same stimuli, normal subjects' performance was near ceiling level. The aphasic subjects failed to show a comparable increase in RT on the lexical decision task. In addition, while the agrammatic aphasics performed above chance, they did not perform as well as expected on the grammaticality judgement task. Results are discussed in terms of the nature of the routines involved in the processing of senten...