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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。
OBJECTIVE: To observe the sEMG signal characteristics of the thigh muscles of normal subjects and stroke patients under passive-active and passive-resistance flexion-extension exercises and to explore whether there is a central mechanism of action. Methods: Twenty-four patients with stroke (experimental group) and 17 normal subjects (control group) participated in this study. Surface electrodes were used to guide and record the changes in passive motor, active-passive motor and anti-resistance motor. SEMG signal of flexion and extension of the bilateral rectus femoris, lateral femoral, intramuscular and biceps femoris were measured by linear and time-frequency analysis (average myoelectricity AEMG, average power frequency MPF, median frequency MF) Multivariate analysis of variance (ANOVA) was performed on active limbs, activity patterns, affected limbs and muscles. Results: The main effects of multivariate analysis of variance (ANOVA) showed that MF, MPF, activities, MF, MPF and AEMG of affected limbs and muscles were significantly different (P <0.001). The results of reciprocal effect showed that MF and MPF of muscle in control group were less than those of inactive side in hemiplegic group, while MF and MPF of muscle in bilateral group were significantly decreased in hemiparetic group The MF and MPF of muscle in 4 groups were significantly increased (P <0.01). CONCLUSIONS: The normal subjects have good regularity of sEMG signals and synchronous changes of MF and MPF on both sides. The hemiparesis patients can increase the recruitment of motor units in the bilateral limbs and reduce the activities in the affected side The recruitment of bilateral limb motor units indicates that the sEMG signal reflects the central mechanism of action.