["Inheritance of the apolipoprotein E (apoE) epsilon 4 allele is a risk factor for developing Alzheimer's disease (AD) and is associated with a lower age of dementia onset. The purpose of this study was to determine whether apoE genotypes differentially influence the course of cognitive decline in AD dementia.", 'We administered nine cognitive tests that assessed explicit memory, attention, language, visuospatial function, frontal-lobe function, and logical reasoning abilities to 66 probable AD patients every 6 to 24 months over a span of up to 5.5 years. We identified apoE genotype by a PCR-based method; there were 16 patients with epsilon 3/3, 34 with epsilon 3/4, and 16 with epsilon 4/4. Using regression statistical methods, we computed the change in performance for each test for each patient over time. We then analyzed the mean change in each test in patients grouped according to apoE genotype.', 'For the AD patients as a group, performance on all cognitive tests declined significantly over time, but the rate of decline did not vary significantly across apoE genotypes on any cognitive test. Specifically, the rate of cognitive decline was not faster in patients with an epsilon 4 allele than in those with epsilon 3/3.'] Does apolipoprotein E genotype influence rates of cognitive decline in Alzheimer 's disease?