Syntactic processing in agrammatic aphasia by speakers of a Slavic language

It is widely believed that agrammatic aphasics have lost the ability to assign complete syntactic representations. This view stems from indications that agrammatics often fail to comprehend complex syntactic structures, as for example, some types of relative clauses. The present study presents an alternative account. Comprehension by Serbo-Croatian-speaking agrammatic aphasics was tested on four types of relative clause structures and on conjoined clauses. The relative clauses varied in type of embedding (embedded vs. nonembedded) and in the location of the gap (subject position vs. object position). There were two control groups: Wernicke-type aphasics and normal subjects. The findings from a sentence-picture matching task indicated that agrammatic aphasics were able to process complex syntactic structures, as evidenced by their well-above chance performances. The success rate varied across different types of relative clauses, with object-gap relatives yielding more errors than subject-gap relatives in all groups. Each group showed the same pattern of errors: agrammatic subjects were distinguished from Wernicke subjects and normal subjects only in quantity of errors. These findings are incompatible with the view that the agrammatics are missing portions of the syntax. Instead, their comprehension deficits reflect varying degrees of processing impairment in the context of spared syntactic knowledge.