Novel Moisture Retention Sponge Electrodes for Developing a Wireless EEG SSVEP-based BCI System

Brain computer interface (BCI) is a method of communication between human brain and external device. Among the existing BCIs, steady-state visual evoked potential (SSVEP) is a common BCI technique due to its excellent signal-to-noise ratio (SNR) and relative immunity against artifacts. However, it remains some limitations regarding applying such technique in practical scenarios; one of the limitations is the trade-off between wet and dry EEG electrodes. In this study, we proposed a novel moisture retention sponge electrode and an innovative differentiable power algorithm for developing SSVEP-based BCI applications. The test of impedance suggested that the sponge electrode exhibited lower impedance compared with metal electrodes, which is adequate when hair is present. The proposed algorithm also demonstrated better accuracy regarding SSVEP-based BCI application. Adopting both innovations could strengthen the feasibility of the real-world applications of BCI.