A Feedback Controlled FES in Rehabilitation

Abstract

A feedback control functional electrical stimulation (FES) system was proposed to prevent quadriceps weakness and drop-foot of the hemiplegia during gait training. The FES system is triggered by a footswitch on the heel of the affected foot to stimulate the tibialis anterior muscle for dorsi-flexion and to turn-off the knee locker in the swing phase through the main controller. The footswitch on the heel of the affected-side can be used to stimulate the quadriceps and turn-on the knee locker for quadriceps weakness in the stance phase. It was revealed that the mean velocity, cadence, stride length, active ankle motion range and functional ambulation category (FAC) were significantly improved. A paired t-test indicated that the differences in the electromyography (EMG) of the tibialis anterior and the quadriceps muscles between patient’s affected foot and unaffected foot were not significant (p>0.05) after 16 weeks of training. The proposed knee locker device with closed-loop FES system is capable of providing a hemiplegic patient with regular walking restoration after appropriate gait training.