Touch-based Brain Computer Interfaces: State of the art

Brain Computer Interfaces (BCIs) rely on the user's brain activity to control equipment or computer devices. Many BCIs are based on imagined movement (called active BCIs) or the fact that brain patterns differ in reaction to relevant or attended stimuli in comparison to irrelevant or unattended stimuli (called reactive BCIs). Traditionally BCIs employ visual stimuli for feedback in active BCIs or as cues in reactive BCIs. However these vision-based BCIs are not suited for people with an impaired visual system and in situations where there is a threat of visual overload. Touch-based BCIs may be a viable alternative but they have hardly been explored so far. This paper presents the state-of-the-art in touch-based BCIs. The feasibility of tactile BCIs based on event related brain potentials to localized vibrations has been shown and tactile BCIs based on steady state brain responses to different vibration frequencies can compete with their gaze-free visual counterparts. We recommend the development of specific hardware paradigms and classification algorithms to improve performance further.