脑卒中患者下肢不同运动时大腿肌群表面肌电信号特征及其中枢机制探讨

目的:观察膝关节被动运动、主动-辅助和抗阻屈伸运动状态下正常受试者和脑卒中患者大腿肌群表面肌电(sEMG)信号特征,探讨其是否存在中枢作用机制。方法:24例脑卒中患者(实验组)和17例正常人(对照组)参加本实验研究,采用表面电极,引导和记录在被动运动、主动-辅助运动和抗阻运动等状态下,分别诱发的屈伸膝关节双侧股直肌、股外侧肌、股内侧肌、股二头肌的sEMG信号并进行线性时、频分析(平均肌电值AEMG,平均功率频率MPF,中位频率MF),对活动肢体、活动方式、患侧肢体和肌肉等进行多因素方差分析。结果:多因素方差分析主效应结果显示:活动肢体MF、MPF、活动方式,患侧肢体和肌肉的MF、MPF、AEMG均有非常显著性差异(P<0.001)。交互效应结果显示:对照组4组肌肉MF、MPF均表现为活动侧小于非活动侧;偏瘫组偏瘫侧活动时,双侧肢体4组肌肉的MF、MPF明显减小,健侧活动时健侧4组肌肉的MF、MPF明显增大(P<0.01)。结论:正常受试者的sEMG信号有很好的规律性,双侧MF、MPF变化具有同步随变性;偏瘫组患者健侧活动时可增加双侧肢体运动单位的募集,患侧活动时可减少双侧肢体运动单位的募集,表明sEMG信号能反映中枢作用机制。

The sEMG Characteristics of the Lower Limbs Muscles in Stroke Patients

Objective To observe the surface electromyogram(sEMG)characteristics of the lower limbs muscles in stroke patients and healthy subjects during the passive and active-assisted anti-resistance movements.Methods Twenty four stroke patients and 17 healthy individuals(control group) participated in this study.sEMG of rectus femoris(RF),vastus lateralis(VL),ventralis medialis(VM)and biceps femoris(BF)was recorded during passive and active-assisted anti-resistance of knee joint in both groups.Average EMG(AEMG),mean power frequency(MPF)and median frequency(MF) were analyzed.Results Multiple factor ANOVA showed that very significant differences in the values of MF,MPF and AEMG between non-paretic and the paretic limbs appeared(P<0.001)and among the mode of activities.Interaction UNIANOVA showed that the values of MF and MPF in moving side were lower than that in non-moving side in control group.The values of MF and MPF were significantly lower in paretic limbs than that in non-paretic(P<0.01).Conclusion Recruitment of motor units in both sides of lower limbs increased in stroke patients during passive or active-assisted anti-resistance movements,indicating that the sEMG reflected the involvement of central nervous system.