The effect of EEG recording on functional MR image quality

Introduction The recording of electroencephalogram (EEG) inside the MR scanner has gained increasing interest, particularly in the field of functional MRl (fMRI) [ 1,2]. EEG recording during fMRI can impair the image quality due to magnetic susceptibility of the EEG electrode assemblies and electromagnetic noise from the EEGrecording equipment. We therefore investigated (1) local signal drop outs and geometric distortions caused by individual components of electrode assemblies, and (2) degrading of the image signal-to noise ratio due to electromagnetic noise.