The development of a knee locker with closed-loop functional electrical stimulation (FES) for hemiplegia in gait training.

PURPOSE: A knee locker with closed-loop functional electrical stimulation (FES) system has been developed to prevent the quadriceps weakness and the drop-foot of the hemiplegia during gait training.

METHOD: The FES system is triggered by a footswitch on the heel of the disabled 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. Besides, the footswitch on the heel of the affected-side can be used to stimulate the quadriceps and to turn-on the knee locker for quadriceps weakness in the stance phase.

RESULTS

It is revealed that the mean velocity, cadence, stride length, active ankle motion range, and functional ambulation category (FAC) have improved significantly from 0.15 +/- 0.04 m sec( - 1), 43.3 +/- 15.4 steps min( - 1), 0.36 +/- 0.11 m, 15 degrees, level 2 to 0.43 +/- 0.21 m sec( - 1), 69.4 +/- 19.1 steps min( - 1), 0.73 +/- 0.17 m, 40 degrees, level 4 respectively for the patient. A paired t-test indicated that differences in the electromyography (EMG) of the tibialis anterior and the quadriceps muscles between patient's disabled (affected-side) foot and normal (unaffected-side) foot are not significant (p > 0.05) after 16 weeks of training.

CONCLUSIONS

It is concluded that this new knee locker with closed-loop FES system is capable of providing the hemiplegia with restoration to regular walking after appropriate gait training.