Predicting motor behavior: an efficient EEG signal processing pipeline to detect brain states with potential therapeutic relevance for VR-based neurorehabilitation

Virtual reality (VR)-based motor therapy is an emerging approach in neurorehabilitation. The combination of VR with electroencephalography (EEG) presents further opportunities to improve therapeutic efcacy by personalizing the paradigm. Specifcally, the idea is to synchronize the choice and timing of stimuli in the perceived virtual world with fuctuating brain states relevant to motor behavior. Here, we present an open source EEG single-trial based classifcation pipeline that is designed to identify ongoing brain states predictive of the planning and execution of movements. 9 healthy volunteers each performed 1080 trials of a repetitive reaching task with an implicit two-alternative forced choice, i.e., use of the right or left hand, in response to the appearance of a visual target. The performance of the EEG decoding pipeline was assessed with respect to classifcation accuracy of right vs. left arm use, based on the EEG signal at the time of the stimulus. Diferent features, feature extraction methods, and classifers were compared at diferent time windows; the number and location of informative EEG channels and the number of calibration trials needed were also quantifed, as well as any benefts from individual-level optimization of pipeline parameters. This resulted in a set of recommended parameters that achieved an average 83.3% correct prediction on never-before-seen testing data, and a state-of-the-art 77.1% in a real-time simulation. Neurophysiological plausibility of the resulting classifers was assessed by time–frequency and event-related potential analyses, as well as by Independent Component Analysis topographies and cortical source localization. We expect that this pipeline will facilitate the identifcation of relevant brain states as prospective therapeutic targets in closed-loop EEG-VR motor neurorehabilitation.