Bristlesensors – Soft, Flexible Dry EEG Electrodesfor Neurofeedback and BCI Applications

Background and Objective Dry EEG sensors are important for BCI technologies to gain wide-spread long-term use. The gel-based ones present inconveniences: gel is wet, it dries up and itches, requires hair washing afterwards, varying impedances and need for periodical recalibration. The existing dry EEG electrodes (typically arrays of metallic pins) have higher impedances than the wet ones, dependent on the level of pressure, and thus stable in time. This pressure makes them “bearable” to some (as opposed to “comfortable”). Quoting one early designer and user of such pin arrays, “the thin pin arrays can hurt your skin if you use them (for) too long” [1]. Here a new dry EEG electrode is proposed, able to outperform electrically the existing dry electrodes while reducing the discomfort by distributing more uniformly and more flexibly the pressure on the skin of the scalp through the hair. The novelty consists in using conductive bristles instead of pins.