Facial muscle activity and EEG recordings: redundancy analysis.

The present study explored the use of redundancy analysis, a multivariate technique for assessment of interset association, to examine facial muscle contamination of EEG recordings in studies involving covert levels of emotional expression. Redundancy analyses were performed on simultaneously recorded EEG and facial EMG data obtained in an emotion induction paradigm. Redundancy indices obtained suggest that (1) the amount of variance in EEG activity that can be explained by facial muscle activity under such conditions is minimal, and (2) the EEG alpha band may be at least as or even more susceptible to muscle contamination as the beta band.