Individual alpha peak frequency tracks Alzheimer's disease progression: A longitudinal pilot study
Ruimin Wang, Takao Yamasaki, Takako Mitsudo, Yoshitaka Matsuda, Satoru Goto, Takenao SugiBackground
Early and accurate tracking of Alzheimer's disease (AD) progression is critical for timely intervention. However, electrophysiological biomarkers capable of capturing long-term neurodegenerative changes remain largely underexplored.
Objective
We investigated whether individual alpha peak frequency (IAPF), an electroencephalography (EEG)-derived measure of dominant neural oscillatory activity, could serve as a longitudinal biomarker of AD progression.
Methods
Twenty-seven patients with AD aged 63–91 years underwent annual EEG and cognitive assessments over 2–7 years. IAPF was extracted from eyes-closed resting-state EEG. Longitudinal associations among IAPF, Mini-Mental State Examination (MMSE) scores, age, and follow-up time were evaluated using repeated-measures correlation and linear mixed-effects models. Annual IAPF changes were compared with those of healthy controls (HC) aged 20–70 years, stratified by decade-based age subgroups. Longitudinal changes in relative spectral power were also analyzed.
Results
Patients with AD showed significant longitudinal declines in both IAPF and MMSE scores, with a positive longitudinal association between the two measures. Mixed-effects models indicated that these declines were better explained by follow-up time after accounting for baseline age than by age at assessment alone. Compared with all healthy-control age subgroups, patients with AD exhibited a significantly steeper annual IAPF decline. Relative theta power increased and alpha/beta power decreased over follow-up, consistent with spectral slowing. However, annualized spectral-power changes showed limited disease specificity, with significant AD–HC differences only for delta and alpha power relative to the oldest HC subgroup.
Conclusions
These findings support IAPF as a non-invasive, temporally sensitive, and clinically accessible biomarker for monitoring AD progression.