EEG-based brain–computer interfaces exploiting steady-state somatosensory-evoked potentials: a literature review
A brain–computer interface (BCI) aims to derive commands from the user’s brain activity in order to
relay them to an external device. To do so, it can either detect a spontaneous change in the mental
state, in the so-called ‘active’ BCIs, or a transient or sustained change in the brain response to
an external stimulation, in ‘reactive’ BCIs. In the latter, external stimuli are perceived by the
user through a sensory channel, usually sight or hearing. When the stimulation is sustained and
periodical, the brain response reaches an oscillatory steady-state that can be detected rather
easily. We focus our attention on electroencephalography-based BCIs (EEG-based BCI) in which a
periodical signal, either mechanical or electrical, stimulates the user skin. This type of stimulus
elicits a steady-state response of the somatosensory system that can be detected in the recorded
EEG. The oscillatory and phase-locked voltage component characterising this response is called a
steady-state som...