Comparison of Alpha Waves and SSVEP Based on Ear-EEG Using Conductive Paste and Gel Sheet

Abstract

The ear-electroencephalogram (ear-EEG) method is used to measure brain activity from regions around ear. It is becoming a popular EEG measurement method due to its characteristics such as wearability, simplicity, and long term measurability. In our previous study, we developed and evaluated a brain-computer interface (BCI) by means of steady-state visual evoked potential (SSVEP) measured via ear-EEG. Some ear-EEG-based SSVEP-BCIs have demonstrated practical performance in assisting people with disabilities in various ways. However, the EEG measurement electrodes used in these devices establish contact with skin through conductive paste that stains subject’s hair and skin. This impairs the simplicity of measurement, impacting the advantages of using ear-EEG. Hence, in this study, we measured and evaluated SSVEP and alpha waves by using electrodes coated with conductive gel sheets. A total of 20 channels of electrodes were installed around the subject’s left and right ears, of which EEG components of 10 channels each were made of conductive paste and gel sheet. While the SSVEP and alpha waves were detected by using both conductive paste and gel sheet as the electrode-skin interface, the electrodes attached to the skin with conductive paste showed better detection performance. This indicates that an ear-EEG-based BCI system can be constructed by using conductive gel sheets instead of conductive paste as the electrode-skin interface. In future studies, we aim to improve the signal detection performance of electrodes by using conductive gel sheets as the electrode-skin interface, subsequently developing SSVEP-BCI systems that are implemented for the progress of society.

Keywords: Steady State Visual Evoked Potential, Ear Eeg, Brain-Computer Interface

DOI: 10.54941/ahfe1004756