Episodic Memory and Hippocampal Volume Predict 5-Year Mild Cognitive Impairment Conversion in Healthy Apolipoprotein ε4 Carriers.

Objective: The Apolipoprotein (APOE) ε4 allele increases the risk for mild cognitive impairment (MCI) and dementia, but not all carriers develop MCI/dementia. The purpose of this exploratory study was to determine if early and subtle preclinical signs of cognitive dysfunction and medial temporal lobe atrophy are observed in cognitively intact ε4 carriers who subsequently develop MCI.

Methods: Twenty-nine healthy, cognitively intact ε4 carriers (ε3/ε4 heterozygotes; ages 65-85) underwent neuropsychological testing and MRI-based measurements of medial temporal volumes over a 5-year follow-up interval; data were converted to z-scores based on a non-carrier group consisting of 17 ε3/ε3 homozygotes.

Differential 5-year brain atrophy rates in cognitively declining and stable APOE-ε4 elders.

Objective: The apolipoprotein E (APOE) ε4 allele is the most important genetic risk factor for late-onset Alzheimer's disease. Many ε4 carriers, however, never develop Alzheimer's disease. The purpose of this study is to characterize the variability in phenotypic expression of the ε4 allele, as measured by the longitudinal trajectory of cognitive test scores and MRI brain volumes, in cognitively intact elders.

Five-Year Longitudinal Brain Volume Change in Healthy Elders at Genetic Risk for Alzheimer's Disease.

Neuropathological changes associated with Alzheimer's disease (AD) precede symptom onset by more than a decade. Possession of an apolipoprotein E (APOE) ɛ4 allele is the strongest genetic risk factor for late onset AD. Cross-sectional studies of cognitively intact elders have noted smaller hippocampal/medial temporal volumes in ɛ4 carriers (ɛ4+) compared to ɛ4 non-carriers (ɛ4-).