輕度認知功能障礙患者的語文連結記憶

Abstract

過去西方研究發現輕度認知功能障礙患者與早期阿茲海默氏症患者皆有較差的連結記憶。本研究依中文字特性產生不同種類的字對，以了解中文使用者裡輕度認知功能障礙患者的語文連結記憶表現，並嘗試修改現有臨床工具，比較不同版本的差異。研究發現輕度認知功能障礙組的連結記憶表現明顯較差，於延宕再認階段有較多語意相關、字形相關、與重組的錯誤再認，且與左側海馬迴體積有顯著地相關。與過去研究一致發現輕度認知功能障礙患者有較差的連結記憶，其中輕度認知功能患者具有較多的語意相關錯誤，暗示阿茲海默氏症前驅期的語意處理功能退化。

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.