An In-Laboratory Comparison of FocusBand EEG Device and Textile Electrodes Against a Medical-Grade System and Wet Gel Electrodes

Abstract

In this study, FocusBand (FocusBand Technologies, T 2 Green Pty Ltd.) textile electrodes were tested against medical-grade wet electrodes to investigate the possible differences in skin-electrode interface behavior and EEG signals’ quality. In vivo electrical impedance spectroscopy and simultaneous forehead EEG measurements were performed with ten healthy subjects. In addition, the FocusBand device was tested in a stand-alone manner against a medical-grade reference system using similar test measurements. Compared to wet electrodes, textile electrodes had higher median absolute skin-electrode impedances five minutes after the attachment, but this difference decreased to 50–55 % of the initial during the first 60 minutes on all measured frequencies (1–1000 Hz). Textile and wet electrodes produced highly consistent EEG signals at forehead Fp1 and Fp2 locations. From those, Fp1 signals were more consistent in terms of normalized cross-correlations and agreement of the relative spectral powers. A stand-alone comparison showed that the FocusBand device can be used to record forehead biopotential signals, but the quality was not as consistent as with the medical-grade system. Based on impedance characteristics, a recording made using FocusBand textile electrodes may be more susceptible to artifacts than recording made using the medical-grade wet electrodes. However, FocusBand textile electrodes can be used, after a short stabilization period, to reliably record forehead EEG signals with a quality almost equal to that reached with medical-grade wet electrodes.

Keywords

• Dry electrode
• electroencephalography
• impedance
• sleep
• textile electrode
• wearable