Peaks of the spectral power and coherence of EEG have been widely analyzed in the study of different subjects. The presence of peaks indicates an underlying structure to EEG patterns [29]. However, our simulation results show that the referential and bipolar EEGs may hinder the appearance of peaks in corrected EEG in the spectral-power and coherence analyses [see, e.g., F7*Cz, F7*Pz, T7*F7, and bipolar EEG (F7–T7)*(Cz–Pz) at 27.5 Hz in Fig. 5(D)].
