Electroencephalogram measurement from the hairy part of the scalp using polymer-based dry microneedle electrodes

This paper reports a successful electroencephalogram (EEG) measurement from the hairy part of the scalp using a polymer-based dry microneedle electrode. The electrode consists of 25 pillars, each of which has a sharp microneedle on the top. Hairs are collected into the gaps of the pillars and the microneedles can reach the scalp surface. Since the microneedles can penetrate through the stratum corneum, no conductive gel is necessary to acquire high quality EEG. We experimentally investigated the pillar diameters in EEG measurement from the occipital region with hairs. The fabricated electrodes successfully measured EEG without any skin preparation or conductive gel.