运动单位数目测定在神经源性疾病中的价值

目的：探讨运动单位数目测定(MUNE)对神经肌肉疾病的诊断价值。方法：应用Viking IV型肌电图仪中的“统计学方法”对85例健康人和56例神经源性病变患者的趾短伸肌和鱼际肌进行测定。记录和刺激电极均为表面电极。结果：对照组的结果显示可重复性好,≤60岁时,运动单位(MU)数与年龄、性别和左右侧无关;＞60岁时,MU数显著减少。56例患者均表现MU数减少,可重复性高于对照组,并且随着病情的好转,功能性MU数增加。结论：MUNE是显示肌肉MU丧失的一种简单、非创伤性的快速方法,是检测神经源性疾病的理想手段之一。     

腹直肌肌电图运动单位电位正常值的建立

目的:建立腹直肌肌电图(EMG)运动单位动作电位(MUAP)各参数正常值。方法:测定109例正常人腹直肌EMG的MUAP的时限、波幅及多相波。结果:腹直肌EMG的MUAP参数分别为:波幅373．78±56．46μV,时限9．95±1．13 ms,多相波19．40％±1．52％。结论:腹直肌EMG各参数能可靠、稳定地测出,有助于脊髓胸段下运动神经元病变的检测。     

具有迭加动作电位波形的EMG信号自动分解研究

本文提出一种不需人工干预的ＥＭＧ信号自动分解算法。算法的学习阶段使用初始的一小段ＥＭＧ记录以估计不同运动单位的动作电位模板。分解阶段根据运动单位发放统计特性，采有基于最小错误率的贝叶斯准则，将ＥＭＧ信号分解为构成它的各运动单位动作电位序列，这里重点讨论了具有迭加动作电位波形的ＥＭＧ信号分解问题。最后利用合成的模拟ＥＭＧ信号及真实ＥＭＧ信号对算法进行了检验，表明其具有很高的分解正确率     

拮抗肌对运动单位平均发放率的变化关系研究

“共驱动”现象是近年来提出的探索人体随意运动过程中神经系统控制机理的新概念,通过对肘关节恒力收缩时主动肌和拮抗肌两种针电极肌电图（NEMG）信号的分解,估计运动单位（MU）的平均发放率（FR）,研究单块肌肉和拮抗肌对运动单位平均发放率随时间的变化趋势和相关关系,实验结果表明,无论肘关节作屈曲和伸展时,主动肌和拮抗肌两者的运动单位平均发放率均随时间而下降且无相移地高度相关,从而从关节水平上论证了神经肌肉系统“共驱动”现象的存在。     

自动递增刺激记录大鱼际肌运动单位估数及其可重复性

目的 :建立自动递增刺激记录正中神经支配的大鱼际肌运动单位估数 (motorunitnumberestimation ,MUNE)正常值并研究其与年龄、性别的关系和该技术的重复性。方法 :用自动递增刺激记录技术估测正中神经支配的大鱼际肌运动单位数 ,检测无神经肌肉病变的正常人 6 0名 ,年龄 2 0～ 88岁 ,平均 5 0 33± 2 0 81岁。结果 :①正常人正中神经支配的大鱼际肌MUNE为 30 0± 83个 ,三个年龄组的MUNE分别为 35 3± 6 3个 (2 0～ 39岁 )、32 2± 5 4个 (4 0～ 5 9岁 )、2 16± 5 9个 (6 0～ 88岁 ) ;②正常人大鱼际肌MUNE与年龄呈负相关 ,与性别无关 ,6 0岁以上组大鱼际肌MUNE比 6 0岁以下各组明显减少 (P <0 0 0 1) ;③大鱼际肌MUNE重复性实验两次检查值相差不显著 (P =0 3)。结论 :自动递增刺激记录正中神经支配的大鱼际肌MUNE为 30 0± 83个 ,随年龄的增大持续性下降 ,特别在 6 0岁后运动单位数下降明显 ,运动单位估数应考虑年龄因素。大鱼际肌MUNE有良好的可靠性和重复性 ,与性别无关。     

甲状腺机能亢进性肌病的临床和肌电图研究

目的：探讨肌电图在甲状腺机能亢进(甲亢性肌病)性肌病中的临床应用价值及其与甲状腺素、病程和性别的关系。方法：对38例甲状腺功能亢进患者进行神经传导速度测定及肌电图检查。结果：38例甲亢患者运动神经及感觉神经传导速度正常，9例肌力减退者运动单位电位(MUP)时限缩短，29例肌力正常者中，MUP时限缩短者16例。男性患者MUP时限缩短的发生率高于女性，T3、T4增高者MUP时限缩短的发生率高于T3、T4正常者。病程短于4个月者MUP时限缩短的发生率较高。结论：EMG检测可发现亚I临床甲亢性肌病，MUP时限为较敏感和客观的指标，并与性别、甲状腺素水平及病程有关。     

巨型肌电图技术及应用价值的回顾

巨型肌电图(macroelectromyography,macro-EMG)是Erik Stalberg等在单纤维肌电图(single fiber electromyography,SFEMG)的基础上改革了电极装置建立的一项电诊断检测技术。与常规同心针肌电图(cn-EMG)不同的是可以记录整个(或运动单位的大部分)运动单位所有肌纤维的电活动。主要用于运动单位的研究和检测,在各种神经肌肉病(包括各种肌源性和神经源性疾病)的诊断和鉴别诊断中均有价值,但由于针电极较粗导致的疼痛问题,而限制了该技术的广泛应用。下面就macro-EMG技术建立的背景、方法学及临床应用情况综述如下。一、macro-EMG技术产…     

运动单位的肌电图评估：电生理活检

运动单位（MU）是指一个α运动神经元（MN）轴突及其所支配的一组肌纤维（MF）,还包括神经-肌肉接头。通过常规针电极肌电图检测,可评价MU产生的特征性电信号,即运动单位电位（MUP）。肌肉随意收缩时MN放电,所有MF均产生动作电位（AP）,这一组MF的AP的总和即形成MUP。     

肌炎患者的临床及肌电图分析

皮肌炎及多发性肌炎 (以下简称肌炎 ) ,是严重危害人们健康的疾病 ,自然病程不定 ,如能早期诊断 ,给予合理而及时的治疗 ,部分患者能长期缓解。本文对 35例肌炎患者进行肌电图检测分析 ,以探讨神经电生理在肌炎患者诊断中的应用价值。1　资料和方法　　 35例为 1995年 5月至 2 0 0 2年 6月在我院神经科及皮肤科临床诊断为肌炎的患者 ,男 5例 ,女 30例 ,年龄 18～ 5 5岁 ,平均 36岁。所有患者的诊断符合Bohan的诊断标准[1] 。临床症状主要表现为肢体近端无力、肌肉疼痛、压痛、肿胀发热、皮炎等。使用美国Nicolet -Ⅳ型神经电生理仪 ,在 2 0…     

68例肌病患者的肌电图与临床的相关性分析

目的：探讨一组肌肉疾病的肌电图（EMG）特点与临床的对应关系。方法：对68例经临床、EMG检测后确诊的肌肉疾病患者[其中皮肌炎（dermatomysitis,DM）15例,多发性肌炎（polymyositis,PM）27例,进行性肌营养不良（progressive muscular dystrophy,PMD）26例]进行了回顾性分析。采用丹麦KeypointEMG仪和美国Nicolet Viking Quest EMG仪,对全部患者进行了EMG和神经传导检测,其中12例行肌肉病理检查。全部患者均行血清肌酶测定。结果：本文68例患者感觉和运动神经传导速度均正常,但不同类型、不同病程、不同严重程度的肌肉疾病EMG表现并非完全相同,并非都是典型的肌原性损害的EMG表现。肌无力很轻的患者,EMG近似正常。进展较快、急性期的炎症性肌病和进展较快的PMD患者,纤颤电位和异常运动单位共存,为典型的肌原性损害改变。一块肌肉中的纤颤电位越多,肌无力发展也越快,程度也较重。炎症性肌病经治疗病情好转后复查,纤颤电位明显减少或消失。缓慢进展的PMD和炎症性肌病恢复期,没有自发电位,仅有运动单位电位的改变,部分患者运动单位大小混合存在。结论：EMG检查结合临床有助于肌肉疾病的诊断和鉴别诊断,以及估计病程、预后和观察治疗效果。     

Model for decomposition of the motor unit action potential 2 Analysis of simulated motor unit action potentials

A model for decomposition of the motor unit action potential (MUAP) which finds an optimal fit of a set of simulated single-fibre action potentials (SSFAPs) to the original MUAP is tested. The composition of SSFAPs which best produces the MUAP is assumed to carry information about the actual distribution of single-fibre action potentials generating the MUAP. Two methods are derived from the model. The first makes use of a fixed set of SSFAPs. In the second method, a gradually expanding set of SSFAPs is built, using a sequence of crosscorrelation, optimal reconstruction and subtraction. In the paper MUAPs are constructed under various well defined conditions. The MUAPs are decomposed by the two methods, and the results are compared with traditional MUAP parameters. Under these conditions, the model obtains parameters with closer biological connections compared with traditional measures.     

Model for decomposition of the motor unit action potential 1 The algorithm

A model for decomposition of the motor unit action potential (MUAP) into its constituent single-fibre action potentials is presented. It finds an optimal fit of a set of simulated single-fibre action potentials (SSFAPs) to the MUAP. The SSFAPs are assumed to originate from muscle fibres at different distances from the electrode, having various delays in time. Two methods for decomposition of the MUAP are derived from this model: first, that the MUAP is decomposed into a fixed set of SSFAPs; and secondly that the MUAP is decomposed into an adaptive, expanding set of SSFAPs. In the second method three steps are used repeatedly. First, the MUAP is cross-correlated with a collection of four SSFAPs. Then the most similar SSFAPs are used to reconstruct the original MUAP. The reconstruction thus obtained is subtracted from the original MUAP to detect activity not yet imitated. This difference (‘residual’) is again used for cross-correlation, restarting in step 1. After a suitable number of iterations, the MUAP is optimally imitated by a set of SSFAPs. The set of SSFAPs, obtained as described, is assumed to give information about underlying anatomical and physiological data (such as fibre number, fibre density, impulse dispersion) of the motor unit under study.     

Motor unit action potential rate and motor unit action potential shape properties in subjects with work-related chronic pain

The objective of this study was to investigate differences in motor control of the trapezius muscle in cases with work-related chronic pain, compared to healthy controls. Ten cases with chronic pain and 13 controls participated in the study. Electromyographic (EMG) signals were recorded from the upper trapezius during five computer work-related tasks. Motor control was assessed using global root-mean-square value (RMS_G), motor unit action potential (MUAP) rate (number of MUAPs per second, MR) and two MUAP shape parameters, i.e. root-mean-square (RMS_MUAP) and median frequency (FMED_MUAP). MR and FMED_MUAP were higher for the cases than for the controls (P<0.05). RMS_MUAP showed a trend for higher values in the chronic pain group (P<0.13), whereas RMS_G did not show a significant difference between the groups. The higher MR, FMED_MUAP and the trend for higher RMS_MUAP suggest that more high-threshold MUs contribute to low-level computer work-related tasks in chronic pain cases. Additionally, the results suggest that the input of the central nervous system to the muscle is higher in the cases with chronic pain.     

运动单位电位多参数分析在肌原性损害中的诊断价值

目的 :探讨运动单位电位 (MUP)多项参数对肌原性损害的诊断价值。方法 :对 10例肌原性病变患者 ,采用棘波触发平均技术 ,得到股四头肌MUP 2 30个 ,肱二头肌MUP 190个 ,胫骨前肌MUP172个 ,对MUP多项参数进行定量分析 ,并与正常对照进行对比。结果 :各项参数与正常对照相比均有显著意义 (P <0 0 0 1～ 0 0 0 0 1) ,经 5 %可信限和均数 - 2 0标准差界值水平的显著性检验和相关性分析 ,证明时限与面积 /波幅比较大小指数、宽度高度指数和面积具有较高的诊断敏感性。结论 :时限与面积 /波幅比对肌原性损害的诊断作用最敏感 ,大小指数、宽高度指数与面积的诊断作用次之 ,波幅的诊断作用最小     

Synthesising of a motor unit potential based on the sequential firing of muscle fibres

A model for the summation of the fibre potentials in a motor unit is presented. A possible mechanism for the recruitment sequence of the various fibres of a motor unit is developed on the basis of anatomical and physiological findings supplemented with a mathematical approach making it possible to take into consideration the spatial and temporal distribution of various fibre potentials. In addition to the commonly accepted parameters of a motor unit potential, stress is laid on the relative position of the recording electrode with respect to the structure of the motor unit and the location of the motor point of the muscle. The model is evaluated both with dipole and dielectric attenuation approaches. The sub-unit concept of a motor unit is critically examined in the light of the results of the model. Attention has been focused on the motor units of the brachial biceps, but the flexibility of the approach also makes it possible to consider motor units of other muscles. The procedure for such generalisations and the respective limitations are discussed. The model provides a unified approach to the diversity of the parameters of the motor unit potential.     

Adaptive motor unit action potential clustering using shape and temporal information

An adaptive algorithm is described that groups motor unit action potentials (MUAPs), detected in a composite EMG signal during signal decomposition, and creates partial motor unit action potential trains (MUAPTs). Data-driven MUAP shape and motor unit firing-pattern based criteria are used to form the clusters. An algorithm for estimating MUAPT temporal parameter, which provides accurate estimates even for partially defined trains, is used to obtain firing-pattern information. No a priori knowledge is required regarding the number of clusters or the distribution of their template shapes. The clustering algorithm when applied to real concentric-needle detected MUAP data provides accurate and useful clustering results. Compared to a classical leader-based algorithm, it provides more robust performance, is better able to estimate the true number of motor units represented in a set of detected MUAPs, and obtains more complete and accurate MUAPTs.     

Single motor unit and spectral surface EMG analysis during low-force, sustained contractions of the upper trapezius muscle

Intramuscular and surface electromyographic (EMG) activities were recorded from the left and right upper trapezius muscle of eight healthy male subjects during 5-min long static contractions at 2% and 5% of the maximal voluntary contraction (MVC) force. Intramuscular signals were detected by wire electrodes while surface EMG signals were recorded with linear adhesive electrode arrays. The surface EMG signals were averaged using the potentials extracted from the intramuscular EMG decomposition as triggers. The conduction velocity of single motor units (MUs) was estimated over time from the averaged surface potentials while average rectified value and mean power spectral frequency were computed over time from 0.5 s epochs of surface EMG signal. It was found that (1) MUs were progressively recruited after the beginning of sustained contractions of the upper trapezius muscle at 2% and 5% MVC, (2) the conduction velocity of the MUs active since the beginning of the contraction significantly decreased over time, and (3) although the CV of single MUs significantly decreased, the mean power spectral frequency of the surface EMG did not show a consistent trend over time. It was concluded that spectral surface EMG analysis, being affected by many physiological mechanisms, may show limitations for the objective assessment of localized muscle fatigue during low force, sustained contractions. On the contrary, single motor unit conduction velocity may provide an early indication of changes in muscle fiber membrane properties with sustained activity.     

A morphological analysis of the macro motor unit potential

The technique of macro EMG is used to investigate the motor unit architecture in a number of pathological conditions. Amplitude and area are the most commonly used criteria, but these parameters alone are not sufficient to assess the complexity of the macro MUP morphology. In an attempt to examine the morphology of the macro MUP in more detail, additional measures were investigated including, (i) average power, (ii) duration, and (iii) number of phases. Macro MUP duration was defined as the time parameter that contains a particular fraction (90%) of the total power of the potential. The above mentioned parameters were evaluated for normal subjects and for patients suffering with motor neuron disease (MND), spinal muscular atrophy (SMA), and Becker's muscular dystrophy (BMD). It is shown that high amplitude and average power macro MUPs give shorter macro MUP duration than macro MUPs with normal amplitude. In contrast, in low amplitude macro MUPs there is a tendency towards a higher duration measure, as compared with the duration of the normal amplitude macro MUPs. Also, t–test results for the duration measure gave a significant difference between the NOR–MND, and no significant difference between the NOR–BMD and NOR–SMA groups at P<0.05. Significant difference between the NOR and the three disease groups investigated was obtained for the parameters log amplitude, log area, and log average power. The number of phases was not significantly different between the NOR and the rest of the groups. In conclusion, the average power and duration parameters can possibly be used as additional discriminators to detect abnormalities of the macro motor unit potential in both needle and surface EMG but further investigation is necessary.     

Relationship between motor activity-related cortical potential and voluntary muscle activation

The purpose of this study was to investigate the relationship between EEG-derived motor activity-related cortical potential (MRCP) and voluntary muscle activation. Eight healthy volunteers participated in two experimental sessions. In one session, subjects performed isometric elbow-flexion contractions at four intensity levels [10%, 35%, 60%, and 85% maximal voluntary contraction (MVC)]. In another session, a given elbow-flexion force (35% MVC) was generated at three different rates (slow, intermediate, and fast). Thirty to 40 contractions were performed at each force level or rate. EEG signals were recorded from the scalp overlying the supplementary motor area (SMA) and contralateral sensorimotor cortex, and EMG signals were recorded from the skin surface overlying the belly of the biceps brachii and brachioradialis muscles during all contractions. In each trial, the force was used as the triggering signal for MRCP averaging. MRCP amplitude was measured from the beginning to the peak of the negative slope. The magnitude of MRCP from both EEG recording locations (sensorimotor cortex and SMA) was highly correlated with elbow-flexion force, rate of rising of force, and muscle EMG signals. These results suggest that MRCP represents cortical motor commands that scale the level of muscle activation.