Dry Electroencephalography Textrode for Brain Activity Monitoring

Abstract

The advancement in smart materials allows researchers to seek smart textiles for wearable health monitoring. Here, a washable and flexible textile-based dry electroencephalography (EEG) electrode that can detect brain activities has been developed. The EEG electrodes were constructed from an electrically conductive cotton fabric with 67.23 Ω/sq produced through printing PEDOT:PSS/PDMS conductive polymer composite on cotton fabric via screen printing. The mechanical properties like flexural rigidity and tensile strength of the conductive fabric were compared against the bare base material and a PEDOT:PSS-printed fabric. The result from an SEM revealed a uniform printing of the PEDOT:PSS/PDMS on the fabric. The signal-to-noise ratio of the textrode was higher than the Ag/AgCl dry electrode i.e. 17.32 (+3.1%) which open the door for long-term EEG monitoring. Moreover, the electrode can give clear and reliable EEG signals up to 15 washing cycles, 60 bending cycles, 5 multiple uses, and 8 hours of continued use.

Validating Poly(3,4-ethylene dioxythiophene) Polystyrene Sulfonate-Based Textile Electroencephalography Electrodes by a Textile-Based Head Phantom

“…The fabric behaves as a twill 1/4 cotton fabric or a twill 2/1 kermel/viscose of the same approximate gram per square reported by Musa et al [38]. The mechanical stability of the work has also been studied in-depth in that article; the textile electrodes were found to be robust to 60 bending, 15 washing cycles, and 5 multiple uses, providing reliable EEG signals [21]. Five replicas of electrodes with 2 cm diameter, as shown in Figure 7c, were constructed to examine the repeatability and reproducibility of signal quality.…”

“…Similar to Tseghai et al [21], a 1:4 proportion of PDMS to PEDOT/PSS was mixed using a stirring rod until a homogenous PEDOT/PSS-PDMS paste was obtained. Then, BTCA, 10% of the weight of paste, was added to the recipe.…”

“…The textile electrode design and construction were also according to our previous work, Tseghai et al [21], where a 67.23 Ω/sq electrically resistive conductive fabric was employed. The fabric behaves as a twill 1/4 cotton fabric or a twill 2/1 kermel/viscose of the same approximate gram per square reported by Musa et al [38].…”

“…Meanwhile, intertrial coherence (ITC) was obtained for wave cycles from 3 to 0.5, epoch time limit from 0 to 1960, and frequency limit from 0.5 to 250 Hz. ITC was analyzed via EEGLAB software that is treated as in Equation (3) according to spectral and coherence estimates on EEG recordings [21].…”

“…For instance, PEDOT/PSS-based [14] and silver-based [13] electrocardiography (ECG) electrodes have been reported to measure heart activity, but a scientific validation was not performed as part of that research as ECG signals were different from person to person and even for the same person over time. Similarly, we have also used poly (3,4-ethylenedioxythiophene) polystyrene sulfonate/polydimethylsiloxane (PE-DOT/PSS/PDMS) electrodes to measure brain activity [17,21], and noticed that it is much more variable, with changes occurring over seconds. Thus, in this work, we focused on the validation of PEDOT/PSS/PDMS-based EEG electrodes.…”