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

• Main Authors: Matias Rusanen, Sami Myllymaa, Laura Kalevo, Katja Myllymaa, Juha Toyras, Timo Leppanen, Samu Kainulainen
• Format: Article
• Language: English
• Published: IEEE 2021-01-01
• Series: IEEE Access
• Subjects: Dry electrode; electroencephalography; impedance; sleep; textile electrode; wearable
• Online Access: https://ieeexplore.ieee.org/document/9539188/

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&#x2019; quality. <italic>In vivo</italic> 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&#x2013;55 &#x0025; of the initial during the first 60 minutes on all measured frequencies (1&#x2013;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.