Investigations of capacitively-coupled EEG electrode for use in brain-computer interface

In this paper, the preliminary investigation for application of capacitive electroencephalogram (EEG) measurement for brain-computer interface (BCI) is described. EEG was obtained by active electrodes that very high input impedance pre-amplifier circuit was mounted on the electrodes. This method enabled EEG measurements through hair without direct contact with scalp and conductive gel applications. The presented electrode was attached to the normal usual baseball cap for nonintrusive daily or long-term use. Subject wore electrode installed baseball cap and EEG signal was measured under experimental BCI paradigms such as alpha wave, steady-state visual evoked potential, P300, auditory steady-state response and motor imagery. The results showed that further studies are still required to apply capacitive sensing methods to clinical neurosciences, however, it can be concluded that steady of the art capacitive electrode technology can be used for engineering applications using current popular BCI paradigms.