Experimental design: after calibration, all participants controlled the BNCI system under two conditions. During condition #1, EEG was used, while during condition #2 merged EEG and EOG signals were used for BNCI control of the hand exoskeleton. During EEG calibration, either a red square (indicating to rest) or green square (indicating to engage in motor-imagery) was shown. For EOG calibration, participants were asked to either look to the left (blue arrow to the left) or to the right (blue arrow to the right). For evaluation of BNCI control, a visual cue indicated not to move (red square) or to close the hand exoskeleton (green square) over 6 minutes in a random order. Visual indications were separated by inter-trial-intervals (ITIs) of 4-6 sec.