Visual evoked potentials (VEPs) are the electrical response of the brain concerned with visual information processing. Amplitudes of VEPs are smaller than that of background EEG activity, and then the stimulus-locked averaging method is usually used for obtaining the waveform. VEP response to each stimulus is not completely the same but has variability for its amplitude and duration. Therefore, amplitude of averaged VEP waveform deteriorates due to their variability in raw data. Feature extraction of background EEG activity during visual stimulation is also one of significant items in VEP analysis. In that case, separation of VEP component and background EEG component (mainly posterior dominant rhythm) is crucial. In this study, amplitudes of VEP component and posterior dominant rhythm were simultaneously estimated by using the EEG model. Usefulness of the proposed method was investigated by comparing the conventional stimulus-locked averaging method and power spectrum averaging method. Influence of the VEP variability and the background activity for estimating amplitudes of VEP and posterior dominant rhythm were analyzed through the simulation study. In addition, the proposed method was applied to actual recorded VEP data and its effectiveness was evaluated. The proposed method will be applicable to accurate VEP analysis and characteristic analysis of background activity under visual stimulus.
