脑卒中患者不同强度随意运动时的sEMG反应特点

目的：观察不同强度静态及动态运动负荷对脑卒中患者四肢肌肉sEMG信号变化的影响,研究脑卒中患者四肢肌肉活动的表面肌电信号特征与其神经运动控制的关系。方法：24例脑卒中患者参加本项研究,采用患、健侧自身对照实验方法设计,采用上肢屈肘和下肢伸膝静态运动,以及肘关节和膝关节动态屈伸运动负荷试验,采集主动肌和拮抗肌的表面肌电信号,分析信号振幅和拮抗比值等sEMG信号活动特征。结果：最大用力收缩时,上、下肢患侧主动肌AEMG小于健侧,而拮抗比大于健侧;小强度静态运动负荷过程中,患侧上肢主动肌的AEMG略高于患侧,拮抗比明显大于健侧。患侧下肢股外侧肌（VL）、股直肌（RF）和股内侧肌（VM）的平均AEMG、?T标准化值大于健侧,拮抗比小于健侧;小强度动态运动负荷过程中,上肢患侧主动肌AEMG明显高于健侧。下肢患侧VL、RF和VM的AEMG均值具有增大趋势,但无明显差异。而患侧拮抗比明显小于健侧。结论：脑卒中患者由于高位神经元和运动控制功能受损,导致其患侧在最大随意收缩时运动单位募集能力下降,而在轻负荷运动时运动单位募集过度。     

脑卒中患者下肢肌肉动态运动负荷下表面肌电信号特征研究

目的:观察动态运动负荷对脑卒中患者下肢肌肉表面肌电信号变化的影响,探讨在动态运动负荷下脑卒中患者_F肢肌肉表面肌电信号特征.方法:11例脑卒巾患者和10例正常人(对照组)参加本实验研究,利用动态运动负荷诱发双侧下肢屈伸膝关节,采用表面电极引导和记录肌电信号并进行线性时、频分析.结果:两组各活动肢体间比较除AEMG斜率均值外MF、MPF、AEMG及MF斜率及MPF斜率均值差异无显著性意义;各活动肌肉间比较MF、MPF、AEMG均值差异有显著性意义,而MF斜率、MPF斜率及AEMG斜率均值无显著性差异;活动肢体因素四个水平间比较除偏瘫组患侧与健侧之间的MF和AEMG、AEMG斜率均值和偏瘫组患侧与正常组左侧的MPF斜率均值有显著性差异外,其余参数在偏瘫组与正常组组内、组间的差异无显著性差异;活动肌肉因素4组肌肉间对比:主动肌与拮抗肌以及协同肌AEMC、MPF差异有显著性,协同肌之间MF、MPF差异有非常显著性,拮抗肌与协同肌差异无显著性.结论:采用快速傅立叶变换方法进行线性功率谱分析和平均肌电值及疲劳试验分析并不能很好地反映动态运动负荷下脑卒中患者下肢肌肉表面肌电信号变化,特别是活动肢体因素,原因尚待深入研究.     

脑卒中患者下肢肌在被动、助力和抗阻等动态运动负荷下表面肌电信号特征研究

目的 观察在被动、助力和主动抗阻等动态运动负荷下脑卒中偏瘫患者下肢肌肉表面肌电信号的特征.方法 对24例脑卒中患者(偏瘫组)和17例正常对照组在被动、助力和主动抗阻等动态运动负荷下诱发双侧下肢屈伸髋及膝关节,记录肌电信号并进行线性时、频分析.结果 偏瘫组中位频率(MF)、平均功率频率(MPF)均值明显减小,平均肌电值(AEMG)均值显著增大(P<0.001);活动侧的MF、MPF显著小于非活动侧(P<0.001),MF、MPF均值助力＞被动＞抗阻活动(P<0.05),AEMG均值抗阻＞助力＞被动活动,MF、MPF均值协同肌增大,AEMG均值拮抗肌及拮抗协同肌＞主动肌及主动协同肌(P<0.01);健侧活动侧MF、MPF均值明显增高,患侧活动侧和健侧非活动侧明显下降;活动侧MF、MPF均值股外侧肌(VL)最大而非活动侧股内侧肌(VM)最大,活动侧、非活动侧AEMG均值股二头肌(BF)最大;偏瘫组双下肢四组肌肉MF、MPF均值减小,患侧以股直肌(RF)最小,健侧以BF最小(P<0.01),双下肢的AEMG均值明显增大,尤以BF增高最明显,特别是健侧下肢;四组肌肉AEMG均值随着运动负荷的增加逐渐增大,其中BF始终是最大,而VM随着运动负荷的增加增大最明显.结论 脑卒中偏瘫患者MF、MPF均值明显减小,而AEMG均值增大;活动侧的MF、MPF小于非活动侧,其中健侧活动侧明显增高,而患侧活动侧和健侧非活动侧明显下降;MF、MPF均值助力＞被动＞抗阻活动;AEMG均值抗阻＞助力＞被动活动,MF、MPF均值协同肌增大,AEMG均值拮抗肌及拮抗协同肌＞主动肌及主动协同肌.     

恢复期脑卒中患者膝关节拮抗肌群在动态运动负荷下对协同收缩率的影响

目的观察动态运动负荷对脑卒中患者膝关节拮抗肌群协同收缩率变化的影响。方法11例脑卒中患者(偏瘫组)和14例正常人(正常组)利用动态运动负荷诱发双侧下肢屈伸膝关节,采用表面电极引导和记录肌电信号并进行线性时、频分析。结果偏瘫组与正常组组内中位频率(MF)、平均功率频率(MPF)、平均肌电值(AEMG)膝关节拮抗肌群协同收缩率均值变化无显著性差异(P>0.05);组间比较,MF膝关节拮抗肌群协同收缩率均值变化无显著性差异(P>0.05);偏瘫组MPF膝关节拮抗肌群协同收缩率明显增高,AEMG膝关节拮抗肌群协同收缩率明显降低(均P<0.01)。结论MPF、AEMG膝关节拮抗肌群协同收缩率能反映动态运动负荷下脑卒中患者下肢肌肉表面肌电信号变化,而MF膝关节拮抗肌群协同收缩率并不能很好地反映动态运动负荷下脑卒中患者下肢肌肉表面肌电信号变化。     

脑卒中患者膝关节拮抗肌协同收缩率的变化规律

目的观察在被动、主动-助力和抗阻等动态运动负荷下对脑卒中患者膝关节拮抗肌群协同收缩率变化的特征。方法24例脑卒中患者作为偏瘫组和17名正常人作为正常组参加本实验研究,利用动态运动负荷诱发双侧下肢膝关节屈伸运动,采用表面电极引导和记录肌电信号并进行线性时、频分析,然后计算协同收缩率并进行单因素及多因素方差分析。结果偏瘫组下肢的中位频率（MF）、平均功率频率（MPF）协同收缩率患侧明显增大而健侧明显下降,平均肌电值（AEMG）协同收缩率患侧明显下降而健侧明显增大（P〈0.01）;MF和AEMG协同收缩率活动侧明显小于非活动侧（P〈0.05）;MPF协同收缩率被动活动明显减少,AE-MG协同收缩率随运动负荷增大而减少（P〈0.001）。结论偏瘫患者患侧拮抗肌群运动单位肌电募集过度,兴奋的同步化程度降低,肌力下降,而健侧拮抗肌群运动单位肌电募集和运动单位兴奋的同步化过度,肌力增加。     

脑梗死后偏瘫患者康复治疗前后sEMG信号变化的研究

目的：观察和分析脑梗死偏瘫患者下肢在康复治疗前后sEMG信号MF和MPF值的变化特征．为康复治疗疗效评定提供电生理依据。方法：20例脑梗死偏瘫患者在治疗前后进行运动功能评定，并在康复治疗前采集健侧及患侧下肢被动运动、主动助力运动时股直肌和半腱肌的肌电信号,采用快速傅立叶变换方法收集MF和MPF值．经过30d至45d的综合康复治疗后，再次采集相同条件下股直肌和半腱肌的MF和MPF值。结果：股直肌和半腱肌在治疗前后被动运动时MF值差异有显著性（P〈0．05），主动运动时MF值差异无显著性意义（P〉0．05）；在治疗前后被动运动和主动运动的MPF值差异有显著性（P〈0．05）。结论：表面肌电图信号可反映脑梗死偏瘫患者患侧下肢在康复治疗前后的运动功能改善情况，MPF值优于MF值，sEMG可作为偏瘫患者的运动功能恢复的评价指标。     

脑卒中患者坐位及站立位胫骨前肌和腓肠肌表面肌电图信号特征研究

目的分析脑卒中患者坐位及站立位胫骨前肌和腓肠肌表面肌电图(sEMG)信号特征。方法选取15例脑卒中患者和15例正常人作为实验组和对照组,令受试者连续做5次由坐到站,采用表面电极引导和记录两侧胫骨前肌和腓肠肌肌电信号并进行线性时、频分析。结果脑卒中患者坐位患侧与健侧、健侧与正常人对应健侧胫骨前肌的平均功率频率(MPF)和中位频率(MF)差异有显著性意义(P<0.05);脑卒中患者健侧与正常人对应健侧腓肠肌均方根差异有显著性意义(P<0.05);脑卒中患者站立位患侧与健侧、健侧与正常人对应健侧胫骨前肌均方根和积分肌电(iEMG)差异有非常显著性意义(P<0.01);脑卒中患者健侧与患侧、患侧与正常人对应患侧腓肠肌均方根和iEMG差异有显著性意义(P<0.05或P<0.01)。结论sEMG是一种简单、实用、可行的康复评定方法。     

脑卒中后偏瘫上肢康复过程中表面肌电分析

目的 观察脑卒中偏瘫患者在康复进程中其偏瘫侧肱二头肌、拇短屈肌及第一骨间背侧肌做最大等长收缩时表面肌电信号（sEMG）变化及其与上肢运动功能恢复间的相关性，为临床制订个体化康复干预方案提供参考资料。 方法 选取20例脑卒中患者（将其纳入实验组）及10例年龄、性别与患者相匹配的健康志愿者（将其纳入正常对照组）。记录所有受试者双侧上肢分别做肘屈、拇屈、食指外展最大等长收缩时肱二头肌、拇短屈肌、第一骨间背侧肌sEMG信号，并跟踪记录患者偏瘫侧上述肌肉sEMG在康复进程中的变化；采用简式上肢Fugl-Meyer量表（FMA）和徒手肌力评定（MMT）评估患者上肢运动功能及肌力改善情况，计算sEMG信号的均方根值（RMS）、中值频率（MDF）及与上肢FMA、MMT评分的相关性。 结果 正常对照组所检肌群RMS及MDF值左、右侧间差异均无统计学意义（P>0.05）；实验组偏瘫侧所检肌肉RMS、MDF值均显著小于健侧及正常对照组水平（P<0.05），健侧RMS、MDF值均显著大于正常对照组水平（P<0.05）。实验组偏瘫侧所检肌肉RMS、MDF值随康复日程延长呈上升趋势，且末次检测值明显大于首次检测值（P<0.05）。实验组患者上肢FMA评分、MMT评分与上肢所检肌肉RMS值、MDF值均具有正相关性。 结论 脑卒中偏瘫侧上肢sEMG既可反映上肢康复进程，又能反映肌力及运动功能恢复情况，可作为一种定量康复评估指标，从而为制订个体化上肢功能康复训练方案提供参考资料。     

运动想象联合优化运动技能训练干预脑卒中后上肢功能障碍的效果

目的：探讨运动想象联合优化运动技能训练干预脑卒中后上肢功能障碍的临床效果。方法：76例脑卒中后上肢功能障碍患者按照随机数字表法分为对照组和观察组各38例，2组均接受常规康复治疗，对照组在常规康复治疗后进行运动想象训练，观察组在常规康复治疗基础上予以运动想象联合优化运动技能训练。治疗前后用表面肌电信号（sEMG）测定患侧上肢三角肌、肱二头肌、肱三头肌、腕伸肌的均方根（RMS）和中位频率（MF），采用Fugl-Meyer上肢评定量表（FMA-UE）、布朗茨手部测试量表（BzH）、改良Barthel指数量表（MBI）对患者进行评定。结果：治疗4周后，2组患侧上肢三角肌、肱二头肌、肱三头肌、腕伸肌RMS和MF值较治疗前均明显增加（均P<0.01），且观察组以上指标均明显高于对照组（均P<0.01）；2组患肢FMA、BzH及MBI评分较治疗前均明显提高（均P<0.01），观察组以上评分均明显高于对照组（均P<0.01）。结论：运动想象联合优化运动技能训练可改善上肢肌肉sEMG指标，提高上肢和手功能，改善患者的日常生活活动能力，干预脑卒中后上肢功能障碍效果显著。     

双关节运动的局部肌肉疲劳与肌电变化

目的：以腕-肘关节为例，探讨不同水平运动负荷诱发尺侧腕屈肌（FCU）和肱二头肌（BB）疲劳过程中sEMG信号与各关节最大屈肌肌力的关系。方法：采集10名青年男性受试者在不同负荷水平（30％、55％、80％MVC）下疲劳过程中尺侧腕屈肌（FCU）和肱二头肌（BB）的表面肌电信号和各关节在疲劳前后的MVC。结果：不同运动负荷强度分别诱发前臂和上臂肌肉疲劳过程中，腕、肘关节最大屈肌肌力明显下降且具有明显负荷强度效应：BB和FCU的MPF与MF单调递减且下降率具有明显的负荷强度效应；不同负荷强度下BB和FCU的MPF和MF下降斜率与肘、腕关节最大屈肌肌力的下降比值之间有明显相关。结论：局部肌肉疲劳过程中MPF和MF下降率变化能够对相应关节最大肌力变化作出比较准确预测。     

Changes in upper limb joint torque patterns and EMG signals with fatigue following a stroke

Purpose : Little is known concerning changes in neuromuscular fatigue following a stroke. The purpose of this study was to evaluate the effect of a stroke on fatigue-related changes in upper limb torque patterns and electromyographic signals. Method : The paretic and non-paretic upper limb of 10 adults (51 - 79 years) who had a stroke (time since stroke: 3 - 75 months) were compared. Subjects had to perform a fatigue task consisting of a sustained maximal isometric contraction in elbow flexion until torque decreased to below 50% of initial. The main variables of interest assessed before, during and after fatigue were: (1) the torque in elbow flexion, as well as associated forces/torques at the shoulder and forearm; (2) the level of voluntary activation; (3) the amplitude (RMS); and (4) frequency content (median frequency) of electromyographic signals. Results : Compared to the non-paretic side, the paretic side showed a lower level of voluntary activation and higher relative torque levels at the forearm and shoulder which could both be exaggerated with fatigue, and a lesser fatigue-related decrease in median frequency. Conclusions : Thus, greater fatigue-related changes in features of the central command (ability to maximally activate a muscle and ability to isolate effort to a muscle group) were observed for the paretic compared with the non-paretic side. This could be a confounding factor when assessing changes in peripheral measures of fatigue following a stroke using voluntary contractions.     

Changes in upper limb joint torque patterns and EMG signals with fatigue following a stroke

Purpose : Little is known concerning changes in neuromuscular fatigue following a stroke. The purpose of this study was to evaluate the effect of a stroke on fatigue-related changes in upper limb torque patterns and electromyographic signals.

Method : The paretic and non-paretic upper limb of 10 adults (51 - 79 years) who had a stroke (time since stroke: 3 - 75 months) were compared. Subjects had to perform a fatigue task consisting of a sustained maximal isometric contraction in elbow flexion until torque decreased to below 50% of initial. The main variables of interest assessed before, during and after fatigue were: (1) the torque in elbow flexion, as well as associated forces/torques at the shoulder and forearm; (2) the level of voluntary activation; (3) the amplitude (RMS); and (4) frequency content (median frequency) of electromyographic signals.

Results : Compared to the non-paretic side, the paretic side showed a lower level of voluntary activation and higher relative torque levels at the forearm and shoulder which could both be exaggerated with fatigue, and a lesser fatigue-related decrease in median frequency.

Conclusions : Thus, greater fatigue-related changes in features of the central command (ability to maximally activate a muscle and ability to isolate effort to a muscle group) were observed for the paretic compared with the non-paretic side. This could be a confounding factor when assessing changes in peripheral measures of fatigue following a stroke using voluntary contractions.     

Differences in Rheobase and Chronaxie between the Paretic and Non-Paretic Sides of Hemiplegic Stroke Patients: a Pilot Study

[Purpose] Rheobase and chronaxie are used to confirm muscle degeneration. For stroke patients, however, the uses of rheobase and chronaxie in determining paretic side muscle degeneration is not yet fully understood. Thus, in this study, we examined the electrical properties of the quadriceps muscles of stroke patients’ paretic side and compared them with their respective values on the non-paretic side. [Method] The subjects were six stroke patients (three females, three males). The pad of an electrical stimulator was applied to the vastus lateralis and vastus medialis regions to measure rheobase and chronaxie until the contractive muscle response to electrical stimulation became visible. [Result] Rheobase was significantly increased on the paretic side compared to that of the non-paretic side of hemiplegic stroke patients. Furthermore, chronaxie was significantly increased on the paretic side compared to the non-paretic side of hemiplegic stroke patients. [Conclusion] These results suggest that stroke affects the sensitivity of skeletal muscle contraction. Therefore, this data may contribute to our understanding of the muscle status of stroke patients.Key words: Rheobase, Chronaxie, Hemiplegic stroke patients     

Myoelectric manifestations of muscle changes in stroke patients

OBJECTIVE: To evaluate the development of myoelectric fatigue in paretic and healthy tibialis anterior muscles of stroke patients. DESIGN: Case series. SETTING: Occupational therapy and clinical neurophysiology unit. PARTICIPANTS: Eight patients with hemiparesis or hemiplegia 9 months to 10 years poststroke. MAIN OUTCOME MEASURES: Current pulses of 0.1-ms width and 40-Hz repetition rate were applied for 10 seconds with a monopolar technique; myoelectric signals (M waves) were detected with surface electrodes. RESULTS: Mean values and initial values of the median frequency (MDF) between paretic and healthy side were statistically different, with the values on the healthy side much higher than the paretic side. Changes of MDF showed a decreasing pattern for both the paretic and the healthy sides, with the downslope of the curve of the healthy side more evident. CONCLUSIONS: In paretic muscles of stroke patients, the tendency toward atrophy of type II fibers appears to be frequent. Our study suggests this muscle rearrangement uses techniques much less invasive than muscle biopsy, and gives useful information about muscle function. This kind of information can help identify rehabilitation strategies, particularly for chronic stroke survivors.     

负重对帕金森病患者上肢肌群表面肌电信号的影响

目的：观察帕金森病（PD ）患者上肢无负重和负重情况下上肢肌群表面肌电信号变化特征。方法：26例帕金森病患者为PD组,28例正常人作对照组,在坐位上肢屈肘无负重和负重1．5kg的静态运动负荷下,采用表面肌电对肱二头肌及屈腕肌群进行线性时、频分析。结果：PD组中位频率（MF）和平均功率频率（MPF）均值高于对照组（P＜0．01）,而平均肌电值（AEMG）值显著低于对照组（P＜0．01）。PD组的肱二头肌MF值、MPF值均小于屈腕肌群（P＜0．05,0．01）;PD组无负重的MF和MPF均值均大于负重时（P＜0．05,0．01）,而无负重时的AEMG小于负重时（P＜0．01）;无负重时肱二头肌的MF均值、MPF均值均小于屈腕肌群（P＜0．05,0．01）。结论：帕金森病患者上肢肌群运动单位募集过度,肌力下降,其中以前臂肌群或上肢无负重时最明显,表面肌电信号可以反映帕金森病患者的肌肉功能。     

The characteristics of multi-directional step distance and the association between stepping laterality and walking ability of patients with stroke

[Purpose] The purpose of this study was to determine the effect of stepping limb and step direction on step distance and the association of step distance and stepping laterality in step difference with walking ability and motor dysfunction. [Subjects and Methods] The subjects were thirty-nine patients with chronic hemiparesis as a result of stroke, who performed the MSL (Maximum Step Length) test along with tests of motor impairment, gait speed and Functional Ambulation Category. The MSL test is a clinical test of stepping distance in which participants step to the front, side, and back. The subjects were classified into three groups according to the stepping laterality in front step distance. [Results] Step distance did not differ across stepping limbs but did differ across step directions. Front step distance was significantly longer than side and back step distance. Participants with forward paretic step length shorter than forward non-paretic step length had significantly higher walking ability than participants with symmetric forward step length or forward paretic step length longer than forward non-paretic step length [Conclusion] Patients with stroke have characteristic step distances in each direction. Adequate weight shift toward the paretic limb when stepping with the non-paretic limb is associated with walking ability.Key words: Maximum step length, Stepping laterality, Stroke     

Limited fascicle shortening and fascicle rotation may be associated with impaired voluntary force-generating capacity in pennate muscles of chronic stroke survivors

BackgroundMuscle weakness is one of the most common motor impairments after stroke. A variety of progressive muscular changes are reported in chronic stroke survivors, and it is now feasible to consider these changes as an added source of weakness. However, the net contributions of such muscular changes towards muscle weakness have not been fully quantified.MethodsAccordingly, this study aims: (1) to compare muscle architecture of the human medial gastrocnemius between paretic and non-paretic sides in seven chronic hemispheric stroke survivors under passive conditions; (2) to characterize fascicle behavior (i.e., fascicle shortening and fascicle rotation) of the muscle during voluntary isometric contractions; and (3) to assess potential associations between muscle architectural parameters and muscle weakness. Muscle architecture of the medial gastrocnemius (including fascicle length, fascicle pennation angle, and muscle thickness) was characterized using B-mode ultrasonography, and fascicle behavior was then quantified as a function of isometric plantarflexion torque normalized to body mass.FindingsOur experimental results showed that under passive conditions, there was a significant difference in fascicle length and muscle thickness between paretic and non-paretic muscles, but no difference in resting fascicle pennation angle. However, during isometric contraction, both fascicle shortening and fascicle rotation on the paretic side were significantly decreased, compared to the non-paretic side. Moreover, the relative (i.e., paretic/non-paretic) fascicle rotation-shortening ratio (i.e., fascicle rotation per fascicle shortening) was strongly correlated with the relative maximum voluntary isometric plantarflexion torque.InterpretationThis association implies that such fascicle changes could impair the force-generating capacity of the muscle in chronic stroke survivors.     

Lesion location alters brain activation in chronically impaired stroke survivors

Recovery of motor function after stroke is associated with reorganization in central motor networks. Functional imaging has demonstrated recovery-dependent alterations in brain activation patterns when compared to healthy controls. These alterations are variable across stroke subjects. Factors identified as contributing to this variability are the degree of functional impairment, the time interval since stroke, and rehabilitative therapies. Here, the hypothesis is tested that lesion location influences the activation patterns. Using functional magnetic resonance imaging, the objective was to characterize similarities or differences in movement-related activation patterns in patients chronically disabled by cortical plus subcortical or subcortical lesions only. Brain activation was mapped during paretic and non-paretic movement in 11 patients with subcortical stroke, in nine patients with stroke involving sensorimotor cortex, and in eight healthy volunteers. Patient groups had similar average motor deficit as measured by a battery of scores and strength measures. Substantial differences between patients groups were found in activation patterns associated with paretic limb movement: whereas contralateral motor cortex, ipsilateral cerebellum (relative to moving limb), bilateral mesial (cingulate, SMA), and perisylvian regions were active in subcortical stroke, cortical patients recruited only ipsilateral postcentral mesial hemisphere regions, and areas at the rim of the stroke cavity. For both groups, activation in ipsilateral postcentral cortex correlated with motor function; in subcortical stroke, the same was found for mesial and perisylvian regions. Overall, brain activation in cortical stroke was less, while in subcortical patients, more than in healthy controls. For non-paretic movement, activation patterns were similar to control in cortical patients. In subcortical patients, however, activation patterns differed: the activation of non-paretic movement was similar to that of paretic movement (corrected for side). The data demonstrate more differences than similarities in the central control of paretic and non-paretic limb movement in patients chronically disabled by subcortical versus cortical stroke. Whereas standard motor circuitry is utilized in subcortical stroke, alternative networks are recruited after cortical stroke. This finding proposes lesion-specific mechanisms of reorganization. Optimal activation of these distinct networks may require different rehabilitative strategies.