A transcranial direct current stimulation system for simultaneous EEG measurement

Abstract

The purpose of this study is to verify whether our in-house transcranial direct current stimulation (tDCS) device based on current limiter can be applied during electroencephalography (EEG) recording without significant inflow of artifacts. In the experiment, anode and cathode electrodes were attached on P4 and P5 according to the international 10-20 system, and eight EEG electrodes were also attached around tDCS electrodes (POz, PO3, PO4, PO7, PO8, Oz, O1, and O2). We measured resting state EEGs while tDCS was applied with different current intensities. Power spectral densities (PSD) of EEGs were estimated for five frequency bands (delta, theta, alpha, beta, and gamma), and they were compared between no stimulation and tDCS conditions. It was shown that EEG spectral results were distorted during tDCS, but which was not significant compared to no stimulation condition and distortion level was almost consistent regardless of current intensity. From the results, we could demonstrate our tDCS device can be used during EEG measurement without significant inflow of artifacts.