Beta rhythm is obtained in alert subjects; it is a fast, low-voltage rhythm that is distributed over the scalp. Most studies examining resting EEG characteristics in alcoholics have reported increased beta power in alcoholics compared with nonalcoholics (Bauer 2001; Propping et al. 1981; Winterer et al. 1998). Propping and colleagues (1981) reported these differences in female alcoholics compared with female nonalcoholics, but not in male alcoholics compared with male nonalcoholics. For the COGA study (Rangaswamy et al. 2002), researchers subdivided the beta frequency band into three bands: beta 1 (12–16 Hz), beta 2 (16–20 Hz), and beta 3 (20–28 Hz). The alcohol-dependent group had increased power in both the beta 1 and beta 2 frequency bands at all loci over the scalp, compared with control subjects; this difference was most prominent in the central region of the brain (between the parietal and frontal regions [figure 1]). The alcoholic group also had increased power in the beta 3 frequency band in the frontal region. Age and clinical variables did not influence the difference.
