tACS generator as method for evaluating EEG electrodes: Initial validation using pig skin

Electroencephalogram (EEG) systems commonly used in laboratory environments are rapidly moving towards real-world applications. In this paradigm shift, new methods for recording and classifying EEG signals are necessary. However, it is challenging to validate the efficacy of new electrodes or other data acquisition components when the target signal cannot be controlled. Here, we propose and validate a method for using an attenuated tACS unit to generate a ground-truth signal in conjunction with porcine skin to determine electrode effectiveness. We highlight the utility of this approach by objectively comparing the signal quality of a chirp signal though porcine skin as measured by four different EEG electrodes, three "dry" and a standard hydrogel. We believe a similar approach could be used with transdermal signals on live humans to observe effects of motion, electrode type, or environment on EEG in order to improve design for use in noisy, non-laboratory settings.