The effect of miniaturization and galvanic separation of EEG sensor devices in an auditory attention detection task

Recent technological advances in the design of concealable miniature electroencephalography (mini-EEG) devices are paving the way towards 24/7 neuromonitoring applications in daily life. However, such mini-EEG devices only cover a small area and record EEG over much shorter inter- electrode distances than in traditional EEG headsets. These drawbacks can potentially be compensated for by deploying a multitude of such mini-EEG devices and then jointly processing their recorded EEG signals. In this study, we simulate and investigate the effect of using such multi-node EEG recordings in which the nodes are galvanically separated from each other, and only use their internal electrodes to make short- distance EEG recordings. We focus on a use-case in auditory attention detection (AAD), and we demonstrate that the AAD performance using galvanically separated short-distance EEG measurements is comparable to using an equal number of long- distance EEG measurements if in both cases the electrodes are optimally placed on the scalp. To this end, we use a channel selection method based on a modified version of the least absolute shrinkage and selection operator (LASSO) technique, viz. the group-LASSO, in order to find these optimal locations.