In summary, to allow reliable meta‐analysis of EEG genetic association study data in ENIGMA, we encourage researchers to use 64 lead recordings or more, use automated cleaning and QC procedures, and perform sensitivity analyses to recording/analysis choices in EEG parameter extraction to safeguard homogeneity across cohorts. Additional phenotyping in the form of (family) history of neurological disorders, psychiatric disorders, and substance use as well as measures of social‐economic status and educational attainment (Abdellaoui et al., 2019) would greatly help in providing additional covariates for the association analyses. EEG should be measured in sufficient duration to yield reliable estimates. But since many oscillatory parameters, even when measured over relatively short periods, are strongly heritable (Linkenkaer‐Hansen et al., 2007; Smit et al., 2005, Smit et al., 2012), this indicates that they generally are reliably estimated. We note, however, that for measures dependent on dynamics changes in oscillatory activity, such as vigilance, longer periods are needed to establish reliable estimates (Jawinski et al., 2018).
