The principle of the system is based on motor imagery, which is measured with the EEG. Since the imagination of a movement in the motor cortex produces activity almost identical to an actual movement, a BCI can use this motor imagery to influence the paretic muscles caused by stroke.
The combination of three different treatment approaches maximizes the chances of successful therapy:
The patient is asked to imagine an upper or lower extremity movement (e.g. dorsiflexion). The signals from this motor imagery are measured with an EEG cap and passed through a biological signal amplifier to a PC or laptop. The signals are then evaluated by the recoveriX system which provides two different kinds of feedback - virtual reality and FES.
If the system detects correct movement imagery, the patient gets real time feedback from an avatar. The patient must sit in front of a screen (similar to mirror therapy) that shows the avatar. For example, if the patient imagines left wrist dorsiflexion, then the avatar will perform the same movement.
Two electrodes are placed on a specific muscle group – e.g. the dorsiflexors. If the user imagines the expected movement, feedback is also provided through the Functional Electrical Stimulation (FES), which activates the muscles that the patient’s damaged motor system can no longer activate through natural means.