Effects of Syntactic Complexity on Sentence Comprehension in the Discourse of Persons with Aphasia

Objectives: The purpose of the current study was to investigate the effects of syntactic complexity on the accuracy of sentence comprehension in the level of discourse of persons with aphasia. Methods: Fourteen individuals with aphasia and 15 age and education-matched normal individuals participated in the study. Participants were presented with the same discourse contexts, but with different syntactic complexity. Syntactically simple discourse contained active sentences and conjoined sentences. On the contrary, syntactically complex discourse consisted of passive and embedded sentences. Accuracy (%) served as a dependent measure in a sentence judgement task. Two-way mixed ANOVA, one-sample t-test, and correlation coefficients were performed. Results: For both simple and complex discourse types, people with aphasia (PWA) demonstrated greater difficulties than normal controls. Active and conjoined sentences were easier to process than passive and embedded sentence types. The two-way interactions were not significant. Discourse comprehension was, in general, related to aphasia severity and comprehension subtest scores of a standardized aphasia battery in the aphasic group. Conclusion: The results revealed that discourse comprehension was affected by the complexity of syntactic structures that composed discourse levels for PWA. Discourse that contained simple sentences elicited better performance than discourse with complex sentence types. It is clinically important to consider the level of syntactic complexity for assessment and treatment in a discourse level.