Table 2.

Search string used for a literature survey.

Combination of keywords
AND	fNIRS OR functional near-infrared spectroscopy OR EEG OR Electroencephalography OR Bio-signal OR Brain signal OR Neuro-imaging OR Optical brain imaging
AND	Gait OR Walking OR Balance OR Sway OR Bio-mechanics OR Bio-mechanics OR Posture OR Postural control
AND	Neurological disorders OR Neural disease OR Neural disorders OR Stroke OR Neuro-rehabilitation OR Cognition OR Motor-cognitive OR Gait disorders
AND	Brain-Computer Interface OR BCI OR Human-machine interface OR Brain-machine interface