Methods of denoising of electroencephalogram signal: a review

Electroencephalogram (EEG) is obtained as a result of electrical activity of neurons in the brain. These signals have very small amplitudes and hence are quite prone to contamination by different artefacts. The major types of artefacts that affect the EEG are baseline wandering, power line noise, eye movements, Electromyogram (EMG) disturbance, and Electrocardiogram (ECG) disturbance. The presence of artefacts makes the analysis of EEG difficult for clinical evaluation and information. To deal with these artefacts, numerous methods and techniques have been evolved by different researchers. These methods include regression, blind source separation, wavelet and empirical mode decomposition etc. This paper provides a review of these methods for denoising of EEG signal.