Within-subject reliability and inter-session stability of EEG power and coherent activity in women evaluated monthly over nine months

Objective Quantitative EEG parameters during resting conditions are used as baseline in research on cognition and in serial-EEG recordings. Despite its increasing use in cognitive research and the numerous evidences of the existence of sex differences in EEG, EEG stability has been mainly investigated in men. Particularly, studies on stability of coherent activity are scarce. The aim of this study was to investigate within-subject reliability and inter-session stability of resting EEG over a nine-month period in women. Methods Within-subject reliability and inter-session stability were analyzed for absolute power and inter- and intrahemispheric coherent activity at central and posterior regions, once a month, in resting conditions, with eyes open and closed. Results Within-subject reliability was very high (r > 0.89) for all subjects and EEG parameters. Inter-session stability was higher with eyes closed and for interhemispheric coherent activity, and poorer with eyes open especially in the alpha band. Conclusions Present results indicate high reliability of the pattern of power and coherent activity of each individual woman during rest, and group stability of EEG activity with eyes closed at least over a nine-month period. Significance These results provide information on EEG stability in women over a long period.