Closed-loop tDCS in Patients in Minimally Conscious State

This research will test a closed-loop system using EEG-arousal measures (spectral entropy) to define the best moment of the day for application of transcranial direct current stimulation (tDCS) in patients in MCS This study aims at answering the following questions: 1. Is tDCS applied during high vigilance states more effective in increasing the level of conscious awareness than low vigilance states in patients in minimally conscious state (MCS)? 2. Is the EEG pattern (connectivity, complexity) different after application of active or sham tDCS at high vigilance or low vigilance states? 3. Is there a difference in the profile of tDCS-responders as compared to non-responders with regards to etiology, clinical diagnosis (MCS+/MCS-), age, gender, time post-injury, functional outcome, structural and functional neuroimaging findings and EEG markers?