轻度认知损伤患者的联系记忆损伤特征

遗忘型轻度认知损伤患者(aMCI)在项目记忆和联系记忆上都有损伤．本文通过临床记忆量表中的项目记忆和联系记忆测验,研究aMCI的联系记忆是否比项目记忆有更显著的损伤．另外,通过分析配对联想学习测验,进一步研究aMCI联系记忆损伤的特点．25名aMCI和28名健康老人参与了两个联系记忆测验(配对联想学习测验和联想回忆测验)和两个项目记忆测验(图像自由回忆和无意义图形再认),aMCI患者在联系记忆测验上表现出了更显著的损伤,即使控制了项目记忆的损伤,aMCI的联系记忆仍然比健康老人显著降低．另外,ROC分析表明联系记忆测验比项目记忆测验对aMCI病人有更高的区分度．对配对联想学习测验的分析表明,相对于健康老人,aMCI患者在记忆有语言联系的词对要比记忆无语义联系的词对更为困难．本研究进一步表明aMCI患者的联系记忆比项目记忆有更大的损伤．相对于健康老人,aMCI患者不仅难以在两个无关项目间创建记忆连接,而且在有效利用项目间本身的语义联系方面存在更大的损伤．联系记忆测验比项目记忆测验对aMCI患者有更高的区分度．在神经心理评估中增加联系记忆测验,能更加有效地识别aMCI患者．

Characteristics of Associative Memory Deficits in Amnestic Mild Cognitive Impairment

Amnestic mild cognitive impairment (aMCI) patients show impairment in both item and associative memory. The current study administered the widely used associative and item memory tests from the Clinical Memory Scale to investigate whether aMCI patients are more impaired in associative memory than item memory. In addition, we aimed to analyze an associative memory test (the paired-associate learning test) in order to investigate in detail the nature of associative memory impairment in aMCI patients. Twenty-five individuals with aMCI and 28 healthy controls took part in the study. Two associative memory tests (paired-associate learning test and associative recall), two item memory tests (free recall of pictures and recognition of meaningless figures), and a set of neurocognitive tests were administered to the participants. aMCI patients performed significantly worse than healthy older adults in both associative memory tests, even when controlling for impairment in the item memory tests. In addition, ROC curve analysis indicated that discriminative power was higher in associative than in item memory tests. Further, the results of the paired-associate learning test indicated that, compared to normal older adults, aMCI patients showed more deficits in remembering the easy word pairs, relative to the difficult word pairs. Our results confirm that aMCI patients demonstrate greater deficits in associative memory than in item memory. In addition to the impairment in creating memory links between items, aMCI patients may have deficits in using the semantic information presented by the items. The associative memory tests showed higher discriminative power than item memory tests in the identification of aMCI patients. Including associative memory testing in future neurocognitive assessment protocols could be helpful to improve the "hit rate" of aMCI detection.