Effects of Syntactic Complexity and Sentence Repetition on Sentence Comprehension in Patients with Dementia of Alzheimer's Type

Objectives: Although various strategies have been developed to improve auditory sentence comprehension in patients with dementia of Alzheimer's type (DAT), there is a lack of clinical validation of their effectiveness. The purpose of this study was to investigate the effects of syntactic complexity and sentence repetition on sentence comprehension in patients with DAT and elderly adults. Methods: Thirty elderly adults and 30 patients with DAT participated in this study. The task used a token test, and sentences was presented once or twice using the Pratt program. Results: First, the differences according to group, syntactic complexity and sentence repetition in sentence comprehension were significant. Second, an effect of sentence repetition on the total score was found in section 1-3 composed of 4-7 syntactic words, but was not found in section 4 composed of 6-18 syntactic words and consisting of sentences with different syntactic complexity in both groups. Third, in the case of the elderly adults, a significant correlation between the total score of the token test and sentence comprehension ability and the repetition of sentences was shown only in section 4 and the total score; whereas in the DAT patient group, a significant correlation in sentence comprehension ability as seen from the results of the total score of the token test and sentence repetition was found in all sections and total scores. Conclusion: These results suggest that the effects of sentence repetition on sentence comprehension in patients with DAT differ depending on the syntactic complexity.