The domain-specific, stage-limited impact of the apolipoprotein E epsilon-4 allele on cognitive functions in Alzheimer's disease

Abstract

To examine the impact of the APOE epsilon4 allele on the cognitive functions of Alzheimer's disease (AD) patients, we administered the eight neuropsychological tests from the Consortium to Establish a Registry for Alzheimer's Disease Neuropsychological Assessment Battery to 118 Korean AD patients. The impact of the APOE epsilon4 allele was significant in the Word List Recall Test (WLRT) and the Word List Recognition Test (WLRcT) only, and its impact was confined to the very mild AD (VMAD) patients (F = 7.65, d.f. = 2, p < 0.01 for WLRT; F = 3.27, d.f. = 2, p = 0.04 for WLRcT). In the VMAD group, the performance on the two tests of the APOE-epsilon4-positive patients was poorer than that of the APOE-epsilon4-negative patients. Our findings suggest that the impact of the APOE epsilon4 allele on cognitive functions in AD may be domain specific and confined to the early stage of AD.