Processing of Visual Evoked Potentials using Mode Deviation

The term visually evoked potential (VEP) refer to electrical potentials, initiated by brief visual stimuli, which are recorded from the scalp overlying visual cortex, VEP waveforms are extracted from the electro-encephalogram (EEG) by signal averaging. VEPs are used primarily to measure the functional integrity of the visual pathways from retina via the optic nerves to the visual cortex of the brain. VEPs better quantify functional integrity of the optic pathways than scanning techniques such as magnetic resonance imaging (MRI). The traditional averaging method can show the shape of the evoked potentials in the rough but losses some important components. Hence it is required to improve the ensemble average of evoked potentials. In this paper we are introducing mode deviation test to identify and remove artifacts and to improve the estimation of evoked potentials. We identify the signals with large mode deviation as artifacts. This test is applied to 14-channel visual evoked potentials of different subjects.