Biomedical Research

Electroencephalography (EEG) is an electrophysiological monitoring technique to capture the brains
electrical activity. It is a noninvasive recording technique in which electrodes are placed over the scalp.
EEG records the variations in voltage resulting from ionic current inside the brain neurons. In a clinical
perspective, EEG corresponds to the recording of the brain's impulsive electrical activity during a given
time period. EEG is used to diagnose epilepsy, sleep disorders, encephalopathies, etc. Hence, EEG
signals are very useful in detecting abnormalities in the human brain. But the main problem in the
analysis of these signals is due to the noise that gets added to them. These artefacts arise due to various
reasons such as due to power line disturbance (50 or 60 Hz) or due to other natural rhythms of the body
like the heartbeat, muscle movement, blinking of eyes etc. These signals get added as noise while
recording of the EEG signal and pose difficulty in correct clinical analysis. Therefore, it is necessary to
develop methods that are efficient in removing noise from these signals. Several methods such as those
based on time and frequency have been earlier utilized but failed due to their inability to remove lowfrequency
noise. In this work, several pre-processing filters have been tested on EEG data. An attempt
has been made to find the best pre-processing technique that can be used for effective cleaning of EEG
signals. From the results obtained it can be concluded that the proposed modified self-filter shows the
best results when compared with other filtering techniques such as Kalman filter, recurrent quantum
neural network (RQNN) filter, moving average (MA) filter, modified self-filter, Savitzky Golay (SG)
filter and Weiner filter.

Author(s): Gauri Shanker Gupta, Maanvi Bhatnagar, Shikhar Kumar, Rakesh Kumar Sinha
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