Multilayer Sweat-Absorbable Textile Electrode for EEG Measurement in Forehead Site

A multilayer sweat-absorbable flexible textile dry electrode for EEG measurement in forehead site was presented in this paper. With the development of BCI and wearable healthcare devices, the demand for long-term EEG monitoring, especially in the forehead site, has been increasing. However, current EEG electrodes cannot fulfill this demand, as wet electrodes need complex operations and conductive gels, and majorities of dry electrodes exhibit unacceptable high impedances. On the other hand, in motion or hot and moisture environment, the human body inevitably produces sweat that leads to short circuits or crosstalk interferences between neighboring electrodes, while current electrodes cannot deal with this situation effectively. To address the above-mentioned issues, a novel flexible dry electrode is designed using multilayer textile materials, including conductive fabrics and sweat absorption acceleration layer, which is able to absorb sweat effectively and further take the sweat as an electrolyte to enhance the conductivity. It also exhibits excellent conductivity with an electrode-scalp impedance superior to the wet electrode and other major electrodes in the literature. A good long-term stability in impedance was observed among current electrodes. A series of tests proved that the electrode was suitable for forehead EEG monitoring in daily life activities with a convenient and quick setup procedure as well as advantages of lightweight, adequate flexibility, and wearing comfort.