The effect of functional electrical stimulation on the contraction pattern of lower limbs muscle in stroke patients in convalescent stage
Objective:To observe the effect of functional electrical stimulation(FES)in walking mode on the lower limb muscle contraction pattern of stroke patients.Method:Thirty patients with hemiplegia in the convalescent stage were included.Electrodes were placed on 4 motion points:the hemiplegic tibialis anterior,quadriceps femoris,gastrocnemius and hamstring muscles respec-tively.The patients walked with FES machine and received electrical stimulation.The surface electromyogram(sEMG)signals were collected on 4 different time:pre-treatment,treatment at 5 min,10 min,and 15 min respectively.Median frequency(MDF)of electromyography reflected the current trend of muscle fatigue,and the co-contraction ratio(CI)showed for contraction pattems of antagonistic muscles in extension of knee and ankle-back,through analyzing the sEMG signals changes of 4 motion points muscle in active contraction.Rat-ed perceived fatigue Exertion(RPE)was used to evaluate the patients'fatigue feeling at 4 time points.Result:The CI of the gastrocnemius muscle during ankle dorsiflexsion and hamstring muscles during knee ex-tension were significantly reduced in electrical stimulation group at 5min and 10min after walking than in the pre-treatment and pseudo-stimulation control groups(P＜0.05);however,the CI of antagonist muscles increased after 15min of the treatment,especially the CI of the hamstring muscles during knee extension was not signifi-cantly different from that before treatment(P＞0.05).The MDF values of tibialis anterior,gastrocnemius,rectus femoris and hamstring muscles in the electrical stimulation group were significantly lower at 5 min,10 min and 15 min of the treatment compare with the pre-treatment and control group(P＜0.05).The MDF value was lower with longer stimulate time,while the control group was significantly lower at 15-min of pesudo-stimula-tion than the level before treatment(P＜0.05).No patients reported fatigue before and after walking with wear-ing FES machine for 5 min,but did after 10 min and 15 min in both groups.The percentages of the patents who reported fatigue in electrical stimulation group at 10min and 15min were higher than that of the control group(40％,80％vs 20％,40％).Conclusion:Functional electrical stimulation for 5-10min can significantly improve the contraction pattern of lower limbs muscle,but the declining muscular coordination when knee extension and ankle dorsiflexsion after 15min stimulation,especially rectus femoris and hamstrings.It is recommended that the walking duration with electrical stimulation machine should not exceed 15 min,in order to avoid the aggravation of fatigue affecting the therapeutic effect of FES treatment.
万方数据
维普
