Study on Brain-Computer Interface Controlled Functional Electrical Stimulation System for Lower Limbs

In this work,in order to restore the movements of lower limbs for paralyzed patients,a functional electrical stimulation(FES) rehabilitation system based on brain-computer interface(BCI) was developed.BCI adopts the technology of steady-state visual evoked potential(SSVEP) based EEG.Linear discriminated analysis was used as the classifier to process frequency-domain features of EEG.Five types of motion intention can be recognized,i.e.start,fast,slow,stop and idle states.The intention recognized was translated as a command to trigger FES system,and stimulated the concerned muscles of lower limbs to generate movements,meanwhile joint angles were measured.Six healthy subjects took part in the pure BCI experiments,and two of the subjects took part in experiments of swinging and walking movements controlled by BCI-FES separately.During swinging experiment,rectus femoris was stimulated.During walking experiment,iliopsoas,glutaeus maximus,rectus femoris,and hamstrings of two legs were stimulated.FES artifacts on EEG were analyzed during experiments.The results showed that the motion intention was well recognized(average recognition accuracy rate was over 85%),and the subjects can realize the expected lower limb movements via FES accordingly.