Apolipoprotein E modulates auditory event-related potentials in healthy aging.

42 individuals ranging from 47 to 73 years of age underwent an auditory three-stimulus oddball task while their event-related potentials (ERPs) were recorded. Half were APOE epsilon3 homozygotes and the remaining participants were either epsilon3/epsilon4 heterozygotes (n=13), or epsilon4 homozygotes (n=8). Analyses of variance showed that the heterozygotes had lower N1 amplitudes than the epsilon3 homozygotes, consistent with a previous study of participants with mild cognitive impairment (MCI) [I. Reinvang, T. Espeseth, L. Gjerstad, Cognitive ERPs are related to ApoE allelic variation in mildly cognitively impaired patients, Neuroscience Letters 382 (3) (2005) 346-351]. APOE genotype also significantly modulated N2 latency. epsilon4 homozygotes had longer N2 latencies, and importantly, longer N2 latencies predicted decline in verbal learning after 3.5 years follow up. These findings indicate a potential clinical significance of individual differences in ERP components N1 and N2.