Indian Journal of Science and Technology

Abstract

This work shows the effect on cognitive performance while playing action video game based on the beta waves variation. The Present work initially shows the Signal to Noise Ratio (SNR) improvement by using an adaptive noise cancellation technique for suppressing the noise, here is to eliminate the ECG artifact from noisy EEG signal and then the wavelet analysis of EEG signals is done to study the brain activity. EEG signal is acquired experimentally from the subject by using the 10-20 system of electrode placement. In first stage the adaptive noise cancellation technique is implemented with the help of an adaptive filter to remove the artifact and hence to improve the signal to noise ratio (SNR). The adaptive algorithm used for the filter is the LMS which is a FIR based digital filter. A synthetic signal is also simulated to give a concept of the effect of the proposed active noise cancellation method to remove the noise or artifact. Synthetic signal analysis shows the suitability of the adaptive noise cancellation technique which is a de-noising tool, and here the de-noised signal is the error signal. Then in second stage, the de-noised signal is processed and the Wavelet Transform is used to provide the information of the β-activity. EEG signals from the frontal and parietal lobes are recorded and the effect is analyzed as the frontal and parietal lobe is associated with reasoning, planning, problem solving and orientation, recognition and perception of stimuli respectively. However, the presence of artifacts like electrocardiogram(ECG) in the EEG signal is a major problem in the study of brain activity. Though it is needed to record cerebral signals, it also records the signals that are not of cerebral origin called artifacts. Artifact removal from EEG signals is essential for better analysis and diagnosis. The EEG signal acquired from a patient is generally noisy and non-stationary by nature. So an adaptive noise cancellation technique is used to remove the artifact and hence the signal to noise ratio of the acquired EEG signal is improved. The EEG signal alone, is acquired from the subject and is used as the reference signal in the ANC noise cancellation technique to get the de-noise EEG signal. Then the de-noised signal is processed and the Wavelet Transform (WT) is used to provide the information of the β-activity. Experiments reveal that the proposed ANC method of noise or artifact removal along with the Wavelet Transform can be used to provide a clear information of the β-activity during the action video game play. The increase in the Beta activity in the eleventh hour of game play than the game play of the first hour indicates increase in cognition due to training in action video game play.

Keywords: Artifacts, Adaptive Filter, Wavelet Transform, ANC, ECG, EEG