Comprehension of Embedded Questions in Broca’s Aphasia: Syntactic or Working Memory Problem?

Background: Sentence processing in Broca’s aphasia is characterized by a specifi c defi cit in comprehension of complex syntax. To clarify whether the defi cit is due to impairment of syntactic knowledge or due to limitations in processing resources in these patients, we investigated comprehension of direct (DQ) and embedded questions (EQ) in six Croatian aphasics. Methods: Six aphasic and three control subjects participated in this study. Th ree patients were Broca’s aphasics; the other three had a predominant Broca’s aphasic component, while exhibiting also elements of mixed aphasia. Experiment 1 tested comprehension of DQ and EQ who and which subject and object questions. Experiment 2 tested comprehension of embedded who and which subject and object questions extended by one (EQ1Ex) and two prepositional phrases (PPs) (EQ2Ex). If aphasics’ comprehension defi cit is due to impairment of syntactic knowledge, then syntactically more complex EQ will be harder to comprehend thanDQ, and object questions will be more diffi cult than subject questions. If syntactic defi cit is due to limitations in aphasics’ processing resources, then comprehension of EQ1Ex and EQ2Ex will be more diffi cult than comprehension of DQ and EQ. Results: Broca’s aphasics performed signifi cantly better on DQ and EQ than on EQ1Ex and EQ2Ex. Th e patients with mixed symptoms showed overall poor comprehension, confirming the previous fi ndings on their more severe comprehension defi cit when compared to Broca’s aphasics. Conclusions: Th e results indicate that the ability of Broca’s aphasic patients to comprehend embedded wh-questions is not affected by syntactic complexity itself, whereas it critically depends on the available working memory resources.