The aim of the study was to determine whether the ε4 allele of
the apolipoprotein E (ApoE) gene was associated primarily with
context-specific memory among individuals at genetic risk for
developing Alzheimer's disease. The effect of ApoE status on
comprehensive neuropsychological results was examined in 176 healthy
adults during baseline cognitive testing in the NIMH Prospective Study
of Biomarkers for Older Controls at Risk for Alzheimer's Disease
(NIMH Prospective BIOCARD Study). The presence of the ε4 allele
was associated with significantly lower total scores on the Logical
Memory II subtest of the Wechsler Memory Scale–Revised and
percent of information retained after delay. Further analysis indicated
the prose recall and retention effect was partially explained by a
small subgroup of ε4 homozygotes, suggesting a gradually
progressive process that may be presaged with specific cognitive
measures. The current results may represent an ε4-associated
breakdown between gist-related information and context-bound veridical
recall. This relative disconnection may be understood in light of
putative ε4-related preclinical accumulation of Alzheimer
pathology (tangles and plaques) in the entorhinal cortex (EC) and among
frontal networks, as well as the possibility of less-efficient
compensatory strategies. (JINS, 2004, 10,
362–370.)