Short-term Resting-state Electroencephalography Fast Activity is Associated with Cognitive Decline in Older Adults: A Population-based Cross-sectional Pilot Study

Electroencephalography (EEG) slowing may help detect and prognosticate mild cognitive impairment (MCI). Whether slowed EEG activity is helpful for non-invasive MCI detection in a health checkup remains uncertain. This cross-sectional secondary study assessed the hypothesis that frontal EEG slowing in short-term resting-state is associated with MCI-suspicious participants over 65 in the Iwaki Health Promotion Project 2022. Participants who underwent the MCI screen test were matched by propensity score to minimize confounding (age and educational history) between the non-cognitive impairment (NCI, n = 14) and suspected-MCI (sMCI, n = 14) groups. The matched sMCI group had increased EEG β power, decreased δ power, θ/β power ratio (TBR), and frontal α asymmetry. No significant differences were found in imaginary coherence and debiased weighted phase lag index (dwPLI) between the groups. Spearman's correlation showed a negative correlation between the MCI screen performance and β power and positive correlations between the performance and δ power, TBR, or α-γ dwPLI. Contrary to the hypothesis and previous findings, these results suggest that fast frontal EEG activity is negatively associated with cognitive performance in older adults. EEG measurements in health checkups may be useful for screening cognitive impairments that are less likely due to neurodegeneration.