Novel dry electrodes for recording electrodermal activity.

Novel carbon/salt adhesive (CSA) electrodes have been found suitable for collecting electrodermal activity (EDA) signals. Ag/AgCl electrodes are considered the standard for collecting EDA signals, because it highly avoids electrodes' polarization. Ag is an expensive commodity. Furthermore, a hydrogel layer is needed for the Ag/AgCl electrodes to collect EDA signals. Adding hydrogel to the electrodes is a cumbersome process. Aforementioned circumstances highlight the need for a more accessible media to collect these signals, allowing EDA use to spread. Dry electrodes made with a mixture of carbon, salt and adhesive has shown to be suitable for collecting bioelectric signals. We have implemented a constant DC-source EDA circuit, with the intention of testing how these electrodes perform for collecting EDA signals. Recruited subjects (N=4) underwent a test including electric shocks, watching a disturbing video and performing the Stroop task. Time and frequency domain correlation were computed. For the obtained skin conductance responses (SCRs), amplitude, onset-to-peak time, and onset difference between the CSA and Ag/AgCl electrodes' acquired SCRs were computed. We found no significant differences on SCRs amplitude and onset-to-peak time between CSA and Ag/AgCl. Furthermore, the difference in onset time for simultaneous SCRs obtained using both media was not different to zero. We conclude that CSA electrodes are a suitable surrogate of Ag/AgCl electrodes for collecting EDA signals on healthy subjects using the implemented DC circuit.