Quantitative EEG fingerprints: Spatiotemporal stability in interhemispheric and interannual coherence.

The aim of our study is to examine the persistence of EEG coherence in the fundamental waves-delta, theta, alpha, and beta-both across spatial domains (within the brain, interhemispheric) and over extended periods (interannual). The long-term stability of a specific EEG wave coherence suggests its potential as a neural fingerprint. A total of 28 participants were included in the intrahemispheric-interannual FFT coherence analysis, comparing EEG data collected years apart. The average interannual interval between the first and second EEG recordings was 7.11 ± 4.56 years, with a range from 1.88 to 19.19 years. The combined data from the two EEG sessions shared 62.7 % of their variance, underscoring significant overlap in their information content. The interannual canonical correlation between the first and second EEGs was 0.792, indicating a strong relationship over time. Overall, alpha coherence, particularly in the frontal lobe, showed marked long-term stability, suggesting it as a strong candidate for an EEG fingerprint. Notably, when comparing fundamental wave coherences in the occipital lobe between the first and second EEGs, only the beta coherence exhibited a remarkable correlation over the years.