Apolipoprotein E and alpha brain rhythms in mild cognitive impairment: a multicentric electroencephalogram study

Area of Science:

• Neuroscience
• Genetics
• Medical Imaging

Background:

• The apolipoprotein E epsilon4 (ApoE4) allele is a known risk factor for Alzheimer's disease (AD).
• Previous studies linked ApoE4 to altered electroencephalographic (EEG) rhythms in AD patients.
• Such relationships remained unconfirmed in the preclinical stage of mild cognitive impairment (MCI).

Purpose of the Study:

• To investigate the association between the ApoE4 allele and resting EEG rhythmicity in individuals with MCI and AD.
• To test if the presence of the epsilon4 allele impacts EEG rhythm sources in both MCI and AD.

Main Methods:

• A multicentric study involving 89 MCI subjects and 103 AD patients.
• Resting eyes-closed EEG data were recorded and analyzed for delta, theta, alpha, and beta rhythms.
• Cortical EEG sources were estimated using low-resolution brain electromagnetic tomography.

Main Results:

• Subjects carrying the epsilon4 allele showed significantly lower amplitudes of alpha 1 and alpha 2 sources in occipital, temporal, and limbic areas compared to non-carriers (p < 0.01).
• This finding was consistent in both MCI and AD groups.
• A novel association was demonstrated between ApoE genotype and cortical alpha rhythmicity in MCI, a preclinical AD state.

Conclusions:

• The study establishes a link between ApoE genotype and EEG phenotypes in MCI, extending previous findings in AD.
• These results highlight the potential for genotype-EEG phenotype studies in predicting AD conversion in MCI.
• Further research is motivated to explore early AD prediction using these biomarkers.