Twin and family studies of the human electroencephalogram: a review and a meta-analysis.

Electrophysiological measures may be useful markers of the genetic underpinnings of complex behavior and psychopathology. Twin and family studies have been used to estimate the genetic contribution to the individual differences in a variety of electrophysiological measures. These studies are briefly reviewed here and published twin correlations from a number of studies with comparable methodology were selected for structural equation meta-analyses. For electroencephalographic (EEG) alpha power (11 twin groups) the heritability estimates in each of the single studies were high (averaged 79%), but it was not possible to equate the twin correlations across studies in the meta-analysis. In contrast, combining the data on alpha peak frequency (five twin groups) revealed a 'meta'-heritability of 81% (95% CI: 76-84%). Aggregating the twin correlations of five twin studies on the P300, the estimated meta-heritability is 60% (95% CI: 54-65%) for P300 amplitude and 51% (95% CI: 43-58%) for P300 latency. It is concluded that genomic variation contributes significantly to individual differences in all EEG and event related potential (ERP) measures studied to date.