IDENTIFICATION AND ELIMINATION OF CARDIAC CONTRIBUTION IN SINGLE-TRIAL MAGNETOENCEPHALOGRAPHIC SIGNALS

A two-step method for identification and elimination of the cardiac co ntribution in single-trial magnetoencephalographic (MEG) signals is pr oposed. In the first step, the mean interfering signal (MIS) in one pe riod is estimated by QRS-synchronous averaging of the raw MEG data. In the second step, a QRS-sgnchronous segmentation of the MEG signals is performed and each signal segment is Gram-Schmidt orthogonalized with the MIS. The above method is applied both to artificial and real MEG data. In each case the heart interference is all but eliminated wherea s the components of interest, generated by the brain, remain almost un affected.