Medial temporal lobe volume of nondemented elderly individuals with poor cognitive functions

Poor cognitive performance of elderly individuals with low educational attainment is often difficult to interpret in dementia evaluation. Lack of education, as well as dementia, is often associated with poor cognitive test performance. To elucidate the underlying structural change of low cognitive performance in elderly individuals with low educational attainment, this study examined the relationship between low cognitive performance (LCP) and brain volumes, especially regions vulnerable to Alzheimer's disease, in nondemented elderly Koreans. Individuals with LCP (n=14) were matched on age and education with individuals with normal cognitive performance (n=14). The two groups were compared on the MR-based volumetric measures in the hippocampus, the entorhinal cortex, the amygdala, the temporal lobe, the frontal lobe, the cerebrum, and the intracranial cavity. Intracranial volume (p<.05) and absolute hippocampus (p<.05) and frontal lobe volumes (p<.05) were significantly reduced in individuals with LCP. Normalized volumes of the hippocampus and the frontal lobe did not differ in the two cognitive performance groups. ICV was associated with the K-DRS scores. General cognitive functioning of the LCP individuals, measured with the Korean version of the DRS, did not deteriorate in the 1- or 2-year follow-up cognitive tests. LCP in a nondemented elderly population with limited education appears to be associated with stable lower intelligence rather than increased risk for dementia of the Alzheimer's type.