Brain-computer interface-functional electrical stimulation: From control to neurofeedback in rehabilitation

Brain-computer interfacing (BCI) in combination of functional electrical stimulation (FES) has been widely used in rehabilitation, but the question about its effect on the improvement in motor learning at the cortical level still remains, and thus the usage of FES as a neurofeedback. Neurofeedback is a vital component in BCI-based rehabilitation, as it aids in faster learning and better performance from the participants. It is without any doubt that the standard visual feedback has been successful in improving the performance of the BCI. The type and design of the feedback depend on the objective of the experiment and individual users. Especially for stroke rehabilitation, FES would also provide a more realistic alternative to the classical visual feedback, as it would be intuitive and natural to the patients. Implementation of FES as a neurofeedback seems natural for BCI rehabilitation, as FES activates the sensory channel to provide maximal inflow in the brain to the efferent outflow of motor commands from the BCI to close the motor loop. As a result, both FES and BCI would influence each other and work to improve the cortical and peripheral learning of the patients.