Removal of ocular artifacts in EEG

Abstract

Electroencephalogram (EEG) is an important medical imaging tool which reflects the electrical activity in the brain. It is recorded over the surface of the brain with respect to time. EEG draws potential from the electrodes which are placed on the scalp, this happens due to the firing of the neurons. These signals are in the order of microvolt shows as low amplitude, which are very much prone to the misrepresentation like overlay of other electrical activities exhibit by eye, muscle, heart etc. The other electrical activities which superimposed on the true EEG signal and forms a cock-tailed signal, the other electrical activity which overlay on the true EEG signal is called as Artifact with respect to the brain electrical activity. Mainly EEG signal gets affected with artifact signal which is near or around the brain like EOG, ECG, EMG, etc. forms their respective artifacts in the EEG signal, this makes the physician to make a wrong analysis of EEG signal and treating the brain activity as abnormal and direct the patient to have diagnosis which causes the serious issue. There are many artifacts that overlay and cause misinterpretation of EEG, like from the side of the patient, machinery and other environmental issues. Among this all causes of the artifacts the Ocular artifact caused from the side of the patient takes a principal position because the Ocular artifact (OA) caused by the eye is very much nearer to the psyche. Hence, in this paper the study of the various methods to remove the Ocular artifacts and their benefits, drawbacks are also stated.