A modeling study comparing the signal-to-noise ratio between tripolar concentric ring and conventional disk electrodes with added common mode noise

Electroencephalography (EEG) has high temporal resolution, but lacks high spatial resolution even after increasing the number of electrodes. Although EEG is intended to record cerebral activity, it also records electrical activities arising from sites other than the brain, artifacts. To remove major artifacts like electrooculogram (EOG), electrocardiogram (EMG) and ECG present in EEG, many techniques have been proposed among which surface Laplacian spatial filtering has found prominence. The authors have compared a Laplacian Tripolar concentric ring electrode system to Disc electrodes in terms of the signal-to-noise ratio (SNR). A four-layer anisotropic concentric spherical head computer model was programmed, then a time-varying dipole was used to generate the scalp surface signals that would be obtained with tripolar and disc electrodes. Common mode white noise was added to the electrodes. Finally, the signal-to-noise ratio was calculated. The results show that signals from tripolar electrodes generated much better signal-to-noise ratio.