A study on EEG signals during eye-closed and eye-open using discrete wavelet transform

Analysis of the electroencephalogram (EEG) signal is a popular method for brain activity tracing. However, a precise experiment design is required in ensuring accuracy and reliability of the recorded signals. This includes the eye state whether to be in a closed or open position based on the experiment requirement. In this study, we have demonstrated significant difference between EC and EO in terms of sub-band frequencies using discrete wavelet transform (DWT). The average percentage energy for DWT coefficients related to delta and theta waves are significantly decreased while interestingly, the percentage energy for DWT coefficients related to alpha waves increased significantly from EO to EC. Meanwhile, there is no significant change in the DWT coefficients related to beta and gamma waves. The significant change is determined when p-value is less than 0.01 for an independent t-test. We conclude that this study has proven that it is important to maintain specific eye states during EEG recording to avoid misinterpretation on the analysis of the brain activities.