肌电生物反馈联合膝关节控制训练对脑卒中偏瘫患者下肢运动功能的临床疗效

目的：探讨肌电生物反馈联合膝关节控制训练对脑卒中偏瘫患者下肢运动功能的临床疗效。方法：选取符合标准的脑卒中偏瘫患者60例随机分为观察组和对照组,各30例。2组患者均接受常规康复治疗,观察组在对照组的基础上,另行肌电生物反馈联合膝关节控制训练,每日1次,每周5次,治疗4周。于治疗前和治疗4周后分别采用简化Fugl-Meyer量表评定患者下肢运动功能,Berg平衡量表（BBS）评定平衡功能,Holden步行功能分级（FAC）评估步行能力。结果：治疗4周后,2组患者的Fugl-Meyer、BBS、FAC评分较治疗前比较均显著提高（P＜0.05）,观察组上述评分均显著高于对照组（P＜0.05）。结论：肌电生物反馈联合膝关节控制训练能够改善脑卒中患者的下肢运动功能,提高平衡能力和步行能力。     

Recovery of locomotion after chronic spinalization in the adult cat

Cats were spinalized (T13) as adults and were trained to walk with the hindlimbs on a treadmill. After 3 weeks to 3 months and up to 1 year depending on the animal, all were capable of walking on the plantar surface of the feet and support the weight of the hindquarters. Interactive training appeared to accelerate the recovery of locomotion and maintain smooth locomotor movements. Despite the obvious loss of voluntary control and equilibrium which the experimenter partially compensated for by maintaining the thorax and/or the tail, the cats could walk with a regular rhythm and a well-coordinated hindlimb alternation at speeds of 0.1-1.2 m/s. Cycle duration as well as stance and swing duration resembled those of normal cats at comparable speeds. The range of angular motion was also similar to that observed in intact cats as was the coupling between different joints. The EMG activity of the hindlimb and lumbar axial muscles also retained the characteristics observed in the intact animal. Some deficits such as a dragging of the foot in early swing and diminution of the angular excursion in the knee were seen at later stages. Thus, the adult spinal cat preparation is considered as a useful model to study the influence of different types of training and of different drugs or other treatments in the process of locomotor recovery after injury to the spinal cord.     

The influences of muscle fibre proportions and areas upon EMG during maximal dynamic knee extensions

This study is an investigation of the relationship between muscle morphology and surface electromyographic (EMG) parameters [mean frequency of the power spectrum (MNF), signal amplitude (root mean square, RMS) and the signal amplitude ratio (SAR; i.e. the ratio between the RMS level during the passive part of the contraction cycle and the RMS level during the active part of the contraction cycle)] during 100 maximal dynamic knee extensions at 90° · s⁻¹. Each contraction cycle comprised of 1 s of active knee extension and 1 s of passive knee flexion. The surface EMG was recorded from the vastus lateralis muscle. Twenty clinically healthy subjects participated in the study, and muscle biopsy samples of the vastus lateralis were obtained from 19 of those subjects. The relationships between muscle morphology and EMG were investigated at three stages of the test: initially, during the fatigue phase (initial 40 contractions), and at the endurance level (the final 50 contractions). Major findings on correlations are that SAR and MNF tended to correlate positively with the proportion of type 1 fibres, and RMS correlated positively with the proportion of type 2 muscle fibres. The muscle fibre areas showed little correlation with the EMG variables under investigation. The results of the present study showed that the three EMG variables of a dynamic endurance test that were investigated (RMS, MNF and SAR) were clearly correlated with the proportions of the different fibre types, but only to a small extent with fibre areas. These findings contradict some of the theoretical models of the EMG, especially for parameters in the frequency domain. Accepted: 17 June 1999     

Effect of muscle length on surface EMG wave forms in isometric contractions

Summary To elucidate the influence of muscle length on surface EMG wave form, comparisons were made of surface EMGs of the biceps and triceps brachii muscles during isometric contractions at different muscle lengths. Muscle lengths were altered by setting the elbow joint angle at several intervals between the limits of extension and flexion. The intensity of the isometric contractions was 25% of maximum voluntary contraction at the individual joint angles. Slowing was obvious in the EMG wave forms of biceps as muscle length increased. The so-called Piper rhythm appeared when the muscle was more than moderately lengthened. The slowing trend with muscle lengthening, though less marked, was also seen in triceps. Zero-cross analysis revealed quasi-linear relationships between muscle length and slowing. Frequency analysis confirmed the development of Piper rhythm. An attempt was made to interpret the slowing associated with muscle lengthening in terms of the propagation of myoelectric signals in muscle fibers. Given the effect of muscle length on EMG wave forms, a careful control of joint angle may be required in assessing local muscle fatigue when using EMG spectral indices.     

Role of incentives in the training of the frontal EMG relaxation response

Male college students were assigned to a feedback condition in which an auditory signal was correlated with forehead electromyographic (EMG) responses or to a control condition in which a constant low tone was provided. Within each condition, half of the subjects were provided with an incentive for successful reductions of EMG levels from session to session. In the control condition incentives were actually given on the basis of performance of yoked feedback partners. The remaining subjects in each condition (no incentive) were instructed that the incentive was available for reliable participation in the experiment. Feedback subjects acquired lower EMG levels than control subjects, and the yoked-incentive subjects acquired lower levels than no-incentive subjects in the control condition. There were no major differences in EMG levels attributable to locus of control orientation. The results are discussed mainly in terms of implications of incentive variables for reinforcement analyses of biofeedback effects and the validity of the locus of control construct in this application.This research was supported in part by NIMH Special Postdoctoral Fellowship No. MH58202-01 to the first author, sponsored by the Institute of Behavioral Sciences, Honolulu, Hawaii. Computer services were provided by the University of Hawaii Computing Center.Portions of this article were presented at the annual meeting of the Biofeedback Society of America, Albuquerque, New Mexico, 1978.     

Surface electromyography and muscle force: limits in sEMG-force relationship and new approaches for applications

The estimation of the force generated by an activated muscle is of high relevance not only in biomechanical studies but also more and more in clinical applications in which the information about the muscle forces supports the physician's decisions on diagnosis and treatment. The surface electromyographic signal (sEMG) reflects the degree of activation of skeletal muscles and certain that the sEMG is highly correlated to the muscle force. However, the largest disadvantage in predicting the muscle force from sEMG is the fact that the force generated by a muscle cannot be directly measured non-invasively. Indirect measurement of muscle force goes along with other unpredictable factors which influence the detected force but not necessarily the sEMG data. In addition, the sEMG is often difficult to interpret correctly. The sEMG-force relationship has been investigated for a long time and numerous papers are available. This review shows the limitations in predicting the muscle force from sEMG signals and gives some perspectives on how these limitations could be overcome, especially in clinical applications, by using novel ways of interpretation.     

Association between energy cost of walking,muscle activation,and biomechanical parameters in older female fallers and non-fallers

Objective

To determine the nervous activation, muscle strength, and biomechanical parameters that influence the cost of walking in older fallers and non-fallers.

Methods

Maximal voluntary isokinetic torque was measured for the hip, knee and ankle of older women. Oxygen consumption was measured at rest and during 8 min of walking at self-selected speed. An additional minute of walking was performed to collect kinematic variables and the electromyographic signal of trunk, hip, knee, and ankle muscles, which was analyzed by the linear envelope. Cost of walking was calculated by subtracting resting body mass-normalized oxygen consumption from walking body mass-normalized oxygen consumption. Stride time and length, and ankle and hip range of motion were calculated from kinematic data.

Findings

Older adult fallers had 28% lower knee extensor strength (p = 0.02), 47% lower internal oblique activation at heel contact (p = 0.03), and higher coactivation between tibialis anterior and gastrocnemius lateralis in each of the gait phases (p < 0.05). For fallers, a higher activation of gluteus maximus was associated with a higher cost of walking (r = 0.55, p < 0.05 and r = 0.71, p < 0.01, before and after heel contact, respectively). For non-fallers, an association between cost of walking and age (r = 0.60, p = 0.01) and cost of walking and thigh muscle coactivation (r = 0.53, p = 0.01) existed.

Interpretation

This study demonstrated that there may be links between lower-extremity muscle weakness, muscle activation patterns, altered gait, and increased cost of walking in older fallers.     

针刺不同穴位对痉挛性偏瘫患者诱发肌电图的影响

目的:比较与分析不同取穴方法对脑卒中后痉挛性偏瘫患者的诱发肌电图的影响。方法:选择脑中风后遗症并伴有单侧上肢痉挛性偏瘫患者11人为实验对象,分别采用对偏瘫肢体的痉挛侧和非痉挛侧进行电针治疗方法,以诱发肌电图中的H波和M波的变化,作为反映脊髓运动神经元兴奋性变化的客观指标。结果:(1)患侧肢体Hmax振幅(7.61±1.23)和H/Mmax比值(0.86±0.19),明显高于健侧Hmax振幅(4.66±1.23)和H/Mmax比值(0.55±0.11)(P<0.01),Mmax振幅无明显差异。(2)针刺刺激非痉挛侧经穴后,Hmax振幅随即由5.32mv降低至1.68mv,刺激停止后并立即未恢复到针刺前水平。(3)针刺后的痉挛侧和非痉挛侧的H/Mmax比值都明显下降,与针刺前比较呈现非常显著性差异(P<0.01),而且非痉挛侧的H/Mmax比值低于痉挛侧。结论:针刺非痉挛侧肢体的穴位,对脑卒中后遗症患者脊髓运动神经元异常活动的抑制效果,明显好于痉挛侧肢体的穴位,其机制可能是通过交互抑制的反射活动,对异常活动的脊髓α运动神经元产生了调整作用。     

PUPILLARY AND ELECTROMYOGRAPHIC CHANGES DURING AN IMAGERY TASK

This study examined the relationship between muscle activity and the increased pupillary dilation observed during cognitive tasks when S is required to indicate task completion. Pupillary and EMG activity were monitored while Ss generated images to words. In two groups, Ss indicated completion of the task either by pressing a key or by releasing it. In two other groups Ss made a key press response that was unrelated to the cognitive task. No key press was required of a fifth group. Results indicated some apparent effect of muscle activity on pupil size during the imagery task and the findings were discussed in relation to other variables affecting pupillary activity.     

操作性肌电生物反馈治疗慢性颈脊髓损伤的疗效观察

目的　观察操作性肌电生物反馈治疗是否能够增强慢性颈脊髓 (C1～ 6)损伤患者上肢各肌的自主肌电信号和肌力。方法　慢性非完全性颈脊髓 (C1～ 6)损伤患者 13 9例 ,为美国迈阿嘧大学医学院附属Jackson医学中心骨、康复科门诊患者 ,病程 >6个月 ,均有不同程度上肢功能障碍和肌力减低 ,而且均为经其它康复方法治疗而无进一步功能恢复者。全部患者均接受 15次 (1个疗程 )、每次 5 0min的治疗。分别记录治疗前、后三角肌中部、肱二头肌、肱三头肌、腕伸肌、腕屈肌、指伸肌和指屈肌的肌电信号和肌力测定分级数据 ,并进行比较和统计学分析。结果　治疗后患者自主肌电信号和肌力均较治疗前有明显提高 ,差异有显著性 (P <0 .0 1)。结论　操作性肌电生物反馈是治疗非完全性、慢性颈脊髓 (C1～ 6)损伤的有效方法。