Grammar and cognition: deficits comprehending counterfactuals in Turkish individuals with Broca's aphasia

Abstract

Background: Comprehending counterfactuals requires a well-developed cognitive system. Individuals with Broca's aphasia have impaired cognitive functioning, which may affect their ability to comprehend counterfactuals.Aims: This study investigated whether cognitive complexity involved in counterfactuals adds to sentence comprehension deficits in Broca's aphasia.Methods & Procedures: The sample consisted of 24 Turkish individuals with Broca's aphasia (mean age: 52.7; SD: 12.7) who were matched in age with a control group of 15 neurologically intact Turkish individuals (mean age: 51.8; SD: 8.5). Each group completed a sentence comprehension task with three sentence conditions: nonconditional, factual, and counterfactual. Nonconditionals did not have if-embedding, whereas factual and counterfactual conditionals were morphosyntactically equivalent if-clauses, but only the latter was cognitively complex.Outcomes & Results: Conditionals were more difficult to comprehend than nonconditionals for the Broca group. Counterfactuals were more difficult to comprehend than the morphosyntactically equivalent factual counterparts for the Broca group. There was no discrepancy between test conditions for the control group.Conclusions: Individuals with Broca's aphasia have difficulty processing counterfactuals due to morphosyntactic complexity (if-embedding) and the cognitive processes involved in comprehending counterfactuals. This indicates that cognitive complexity adds to sentence comprehension deficits in Broca's aphasia.