Flower electrodes for comfortable dry electroencephalography

Abstract

Dry electroencephalography (EEG) electrodes provide rapid, gel-free, and easy EEG preparation, but with limited wearing comfort. We propose a novel dry electrode comprising multiple tilted pins in a flower-like arrangement. The novel Flower electrode increases wearing comfort and contact area while maintaining ease of use. In a study with 20 volunteers, we compare the performance of a novel 64-channel dry Flower electrode cap to a commercial dry Multipin electrode cap in sitting and supine positions. The wearing comfort of the Flower cap was rated as significantly improved both in sitting and supine positions. The channel reliability and average impedances of both electrode systems were comparable. Averaged VEP components showed no considerable differences in global field power amplitude and latency, as well as in signal-to-noise ratio and topography. No considerable differences were found in the power spectral density of the resting state EEGs between 1 and 40 Hz. Overall, our findings provide evidence for equivalent channel reliability and signal characteristics of the compared cap systems in the sitting and supine positions. The reliability, signal quality, and significantly improved wearing comfort of the Flower electrode allow new fields of applications for dry EEG in long-term monitoring, sensitive populations, and recording in supine position.

An ecological study protocol for the multimodal investigation of the neurophysiological underpinnings of dyadic joint action

“…To this aim, we developed a novel dry electrode ( Warsito et al, 2023 ), specifically addressing the needs of ecological joint action studies. The novel design is based on our previous dry electrodes ( Fiedler et al, 2015 , 2022 ; di Fronso et al, 2019 ) using an electrically non-conductive but mechanically flexible polyurethane substrate.…”

“…A subsequent coating of Silver/Silver-Chloride (Ag/AgCl) is applied using a multi-phase plating process ( Mota et al, 2013 ), which ensures reliable signal quality ( Fiedler et al, 2014 , 2015 ), electrochemical stability, and mechanical durability ( Fiedler et al, 2022 ). The novel flower-shaped design and specifically adapted substrate hardness ( Fiedler et al, 2018 ) ensure both a reliable electrode-skin contact and considerably increased comfort ( Warsito et al, 2023 ). The individual angled pins, arranged in an intertwined layout on a common baseplate, allow pre-defined deformation of the electrode and therefore adaptation to individual head shapes and compensation of excessive pressure during application and wearing.…”

“… Design of the novel Flower electrode and cap: (A) cap from the outside showing the equidistant electrode layout ( di Fronso et al, 2019 ) and (B) turned inside out showing the individual flower electrodes; (C) magnification of a single flower electrode with 30 pins ( Warsito et al, 2023 ). …”

“…However, on both aspects, state-of-the-art mobile EEG can be considered superior to mobile fNIRS systems. Most specifically, commercial mobile HD-EEG systems comprise, e.g., 64 to 256 lightweight electrodes (Delaux et al, 2021;Stoyell et al, 2021;Fiedler et al, , 2023 fully integrated into cap systems covering the entire scalp. Therefore, 10.3389/fnhum.2023.1305331 EEG may currently be the best choice for hyperscanning studies of joint actions involving full body movements.…”