Characteristics of cognitive function in early and late stages of amnestic mild cognitive impairment

Abstract

The detection of the early stages in amnesic mild cognitive impairment (aMCI) is considered important in diagnosing progression to Alzheimer's disease. The current study sought to investigate differences in cognitive function between control subjects with no memory loss (control), and subjects in the early stage of aMCI (EMCI) and late stage of aMCI (LMCI). A total of 100 community-dwelling older adults aged 65 years and over were recruited from 1543 potential subjects. Subjects were classified into three groups based on the degree of objective memory impairment; control (n=29), EMCI (n=34) and LMCI (n=37). Multiple neuropsychological tests were carried out to examine cognitive function. The EMCI individuals showed lower cognitive function relative to controls; not only in logical memory, but also in letter fluency (P<0.05). There were no significant differences in neuropsychological scores between the EMCI and LMCI groups, except for category fluency and logical memory. In addition, the EMCI subjects' logical memory score showed a significant relationship with letter fluency, category fluency and digit span backward test performance (P<0.05). These results suggest that the application of multiple neuropsychological tests might be useful in diagnosing older adults with EMCI and LMCI.