An estimated 20% of stroke survivors suffer from spastic drop foot, the inability to dorsiflex the foot which can lead to insufficient toe clearance during the swing phase of gait. A common treatment of foot-drop is the use of an ankle-foot orthosis (AFO) that supports the ankle and foot to preclude foot-drop. And, robot assisted gait therapy is an emerging rehabilitation practice for the gait training of subjects suffering from neurologic impairments such as stroke and spinal cord injuries.
Therefore, In this paper we were to develop and estimate the powered lower-limb orthosis with pneumatic rubber actuator for preventing foot drop during walking. This orthosis could assist dorsiflexion motion to prevent foot drop during swing phase of gait. The purpose of this study was to evaluate the performance of orthosis for the prevention of foot drop.
First, seven elderly people(age 67.5 ± 2.5year, height 160 ± 6cm, weight 58.5 ± 11.5kg) and ten young people(age 22.5 ± 1.5year, height 179.5 ± 4.5cm, weight 79 ± 14kg) were selected. The subjects walked three different conditions(no orthosis ; no, non active with orthosis ; na, active with orthosis ; a) on a treadmill. EMG signals four leg muscles were taken and analyzed. In the result, EMG signals of tibialis anterior was lower(p<0.05) when active with orthosis in both group. The result showed that the muscular activities in tibialis anterior muscle were reduced because of the assistance of dorsiflexion torque in ankle joint using the lower limb orthosis.
Second, ten healthy male(age 23±3year, height 170±5cm, weight 70±10kg) participated in this study. The subjects walked three walking conditions on a treadmill(flat, uphill, downhill). EMG signals four leg muscles(rectus femoris ; rf, biceps femoris ; bf, tibialis anterior ; ta, gastrocnemius ; gn) were taken and analyzed. In the result, EMG signals of tibialis anterior was lower(p<0.05) when active with orthosis. The result showed that tibialis anterior was assisted because of lower limb orthosis using pneumatic rubber actuator.
As a result of this study, Lower-limb orthosis using pneumatic rubber actuator is effective assisting tibialis anterior. Lower-limb orthosis for the assistance dorsiflexion can be applied as a part of rehabilitation program for hemiplegia having foot drop caused by stoke.