title: Apolipoprotein E epsilon 4 affects new learning in cognitively normal individuals at risk for Alzheimer's disease.
abstract: The Apolipoprotein E (APOE) epsilon 4 allele is an important risk factor for Alzheimer's disease (AD). Given the interest in early identification of at-risk individuals, we examined memory decline as a function of APOE status and age in cognitively intact participants aged 48-77 years old (yo). Participants were grouped by age (<60 versus > or =60) and APOE (epsilon4+/-). Longitudinal analysis of several components of memory over a 2-year interval showed a significant Age-by-APOE interaction reflecting a decline in new learning for the > or =60 epsilon4+ group only. Among epsilon4+, 76% of the > or =60 participants showed a decline versus 32% of the <60, but the amount of decline in new learning over the 2-year interval within the > or =60 group was not further influenced by age. That is, the size of the 2-year change was the same for 60 and 70 year old participants. This suggests that longitudinal study of new learning is a sensitive measure for detecting early cognitive changes in at-risk individuals that precede the symptomatic onset of mild cognitive impairment and AD.
authors.affiliation: Neuropsychology Neuroimaging Laboratory, Barrow Neurological Institute, St. Joseph's Hospital and Medical Center, 222 W. Thomas Rd., Suite 310, Phoenix, AZ 85013, USA. lbaxter@chw.edu
authors.forename: Leslie C
authors.initials: LC
authors.lastname: Baxter
authors.forename: Richard J
authors.initials: RJ
authors.lastname: Caselli
authors.forename: Sterling C
authors.initials: SC
authors.lastname: Johnson
authors.forename: Eric
authors.initials: E
authors.lastname: Reiman
authors.forename: David
authors.initials: D
authors.lastname: Osborne
mesh_terms: D000368:Aged; D000375:Aging / Q000502:physiology*; D000544:Alzheimer Disease / Q000175:diagnosis / Q000235:genetics*; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D005260:Female; D005787:Gene Frequency; D020022:Genetic Predisposition to Disease; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008568:Memory / Q000502:physiology; D008875:Middle Aged; D012307:Risk Factors; D014706:Verbal Learning / Q000502:physiology*
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E