Although there is considerable inter-individual variability, the distinctive resting EEG pattern of an individual tends to be stable throughout healthy adulthood [8]. Test-retest reliability for resting EEG power is high (r = 0.8–0.9) [15]–[17]. The heritability of eyes closed, resting EEG power using monopolar references (as in our study) tends to be the same at all scalp locations [17]–[19] and has been shown to be approximately 80–85% for theta, alpha and beta and 40% for delta in twin studies [18]–[22] and 23–68% in one large family based study [23]. The same genes appear to influence alpha power throughout the brain [18]. Genetic correlations between alpha, beta, theta and delta power (0.55 to 0.75) indicate that a substantial portion of the genetic variance can be attributed to a common source [17], however frequency band-specific and region-specific genetic factors are also influential [19].
