Idiom Processing Abilities according to Task Types in Patients with Dementia of Alzheimer's Type

Objectives: The purpose of this study is to investigate idiom processing abilities according to task types in patients with dementia of Alzheimer's type (DAT) and healthy elderly adults. Methods: Fifteen patients with DAT and 15 elderly adults participated in this study. They took part in an idiom processing task (picture selection/oral definition) and a cognitive function test (Korean-Mini Mental State Examination [K-MMSE], Seoul Verbal Learning Test [SVLT]). The relationship between the idiom processing ability and cognitive function was examined. Multiple stepwise regression analyses were employed to explore the best cognitive function predictor of idiom processing ability in patients with DAT. Results: First, DAT patients demonstrated worse performance on idiom processing ability than healthy elderly adults in both tasks, suggesting that DAT patients interpreted the idiom more literally than healthy elderly adults. There was a significant correlation between the idiom oral definition and delayed recall scores on the SVLT and K-MMSE in the DAT group. There was a significant correlation between idiom oral definition and immediate recall scores on the SVLT in the healthy elderly adults group. Regression analyses suggested that the delayed SLVT recall scores were the most influential predictor for the idiom oral definition. Conclusion: Patients with DAT exhibited difficulties in processing idioms due to impairment in the ability to suppress literal meaning. Long-term memory appeared to be the best predictor of idiom oral performance in patients with DAT.