Verbal Associative Memory in Individuals with Mild Cognitive Impairment

Background: Previous studies have demonstrated individuals with mild cognitive impairment (MCI) and early Alzheimer’s disease (AD) were defective in associative memory performances compared to healthy controls (HC). However, it remains unclear how verbal associative memory is affected in Chinese speakers with MCI, given the unique features of the Chinese language as oppose to the alphabetic language. Objective: The study aimed to examine verbal paired memory in Chinese speakers with MCI compared to normal aging. Methods: Twenty-two MCI and 25 age- and education-matched HC participated in the study. All participants underwent a comprehensive neuropsychological battery, a word association task, and a modified recognition test of Verbal Paired Associate subtest of the Wechsler Memory Scale -Third Edition (Verbal PA of the WMS-III). In addition, they underwent a structural magnetic resonance imaging. Results: The results showed that the MCI group had worse associative memory compared to the HC group even after controlling performance of item memory. During the delayed associative recognition, the MCI group committed more semantically-related, orthographically-related, and rearranged type false alarms compared to the HC group. The scores of associative memory were also significantly correlated with left hippocampus volume. In addition, performance on the modified recognition of Verbal PA of the WMS-III versus the original version was found significantly different. Conclusion: These results are in line with studies that showed associative memory impairment in individuals with MCI. The high number of semantically-related false alarms found in individuals with MCI suggests possible early disruptions in semantic processing in prodromal AD.