Abnormal event-related potentials in young and middle-aged adults with the ApoE ε4 allele

The largest genetic susceptibility factor for Alzheimer's disease is the Apolipoprotein E (ApoE) ε4 allele. Cognitive decline and olfactory impairment are greater in those positive for the ε4 allele. This study sought to determine if the olfactory event-related potential (OERP), compared to the visual ERP, would be sensitive to these subtle declines. Participants included 40 individuals from two age groups, half of each group were ε4 allele positive and half were ε4 negative. Visual ERPs did not demonstrate significant differences between ApoE groups. OERPs demonstrated robust age by ApoE interactions. P3 latencies were significantly longer in ε4 young and middle age participants. These findings suggest that very early olfactory and cognitive changes related to ApoE status are detectible via the OERP.

► Olfactory event-related potential (OERP) response discriminated ε4+ from ε4− adults.
► OERPs demonstrated robust effects of the ApoE ε4 allele on P3.
► Subtle cognitive declines in ApoE ε4, captured in the OERP, may occur very early.