Impedance evaluation of textile electrodes for EEG measurements

Abstract

In this paper, we evaluated the impedance of textile electrodes for electroencephalography measurements. We compared the commercially available standard dry silver/silver chloride dry electrodes, copper-based, and silver-based textile electrodes by measuring impedance on the skin. First, on dry skin, the impedance range of the electrodes was 93–350 kΩ at 0 min; after 60 min, the range was 20–56 kΩ. The commercial electrode showed the lowest impedance of 20 kΩ, and the silver-based textile electrode showed the highest impedance of 56 kΩ in dry skin conditions after 60 min. When tap water was applied as an electrolyte, the impedance range was 13–15 kΩ at 0 min; after 60 min, the range was 17–22 kΩ for all three types of electrodes. In this case, the copper-based textile electrode showed the lowest impedance of 17 kΩ and the commercial electrode showed the highest impedance of 22 kΩ after 60 min. When saline water was applied as an electrolyte, at 0 min, the impedance range was 8–11 kΩ; after 60 min, the range became 11–12 kΩ for all three types of electrodes. Thus, all electrodes showed similar results. It was concluded that the copper-based textile electrodes were more suitable than the silver-based textile electrodes and comparable to commercial electrodes regarding impedance in all three skin conditions.

Porous Conductive Textiles for Wearable Electronics

“… ,− Skin-contact impedance is a key parameter for evaluating electrodes, as low contact impedance and low variations can contribute to stable and high-quality recordings of electrophysiological signals. However, despite the intrinsic conductivity of PCTs, their contact impedance is much higher than that of gel counterparts . This is because both textiles and human skin are highly porous and rough, which creates numerous gaps between their contacts.…”

“…However, despite the intrinsic conductivity of PCTs, their contact impedance is much higher than that of gel counterparts. 480 This is because both textiles and human skin are highly porous and rough, which creates numerous gaps between their contacts. Furthermore, due to the absence of adhesives, the contacts between textile electrodes and the skin are prone to movement, resulting in unstable contact impedance.…”

Hook Fabric Electroencephalography Electrode for Brain Activity Measurement without Shaving the Head

“…These limitations have led to the emergence of textile-based elect encephalography (EEG) electrodes. Therefore, in a previous study [24][25][26], we succe fully developed dry EEG electrodes from PEDOT:PSS/PDMS-printed cotton fabric [2 The electrode-collected EEG signals are comparable to those of the dry Ag/AgCl EE comb electrodes; however, placing such an electrode on the hairy part of the head is n possible because it is a flat electrode. Thus, shaving the head is compulsory prior to t use of this electrode.…”