Some individuals exhibit very low levels of alpha activity. Recent studies have indicated that such low-voltage alpha (LVA) is associated with anxiety, including anxiety comorbid with alcoholism (Enoch et al., 1999). There is also indirect evidence of an association between LVA and variance common to antisocial behavior and alcoholism (Ducci et al., 2009). Robust individual differences are observed for the dominant (or peak) frequency of the alpha rhythm, which declines with aging (Obrist, 1979) and neurodegenerative diseases such as Alzheimer’s (Stam, 2005). Individual differences in alpha peak frequency have been reported to be associated with working memory (Clark et al., 2004) and intelligence (Grandy et al., 2013), although not in all studies (Posthuma, Neale, Boomsma, & de Geus, 2001). Like alpha power, alpha peak frequency is highly heritable, with estimates of approximately .80 (Posthuma et al., 2001; C. M. Smit, Wright, Hansell, Geffen, & Martin, 2006). Although there is a modest (inverse) phenotypic correlation between alpha power and peak frequency, bivariate biometric models fit to twin data indicate that they are genetically independent (C. M. Smit et al., 2006).
