Removal of Ballistocardiographic Artifacts from EEG Recorded Inside the MR Scanner Using an Optical Motion-Tracking System

Pierre LeVan¹, Julian Maclaren¹, Michael Herbst¹, Jrgen Hennig¹

This study investigates the use of accurate motion-tracking to remove ballistocardiographic (BCG) artifacts in EEG recorded inside the MR scanner. These artifacts, due to heartbeat-related head motion in the magnetic field, are usually corrected by an averaged artifact subtraction (AAS) method, which consists of subtracting a template formed by averaging EEG signals from each cardiac cycle. However, AAS cannot model artifact variability across cardiac cycles, preventing a complete removal of BCG artifacts. Motion measurements during scanning were used to regress out residual BCG waveforms, resulting in significantly reduced root-mean-square residuals across cardiac cycles and improved EEG quality.