50例臂丛神经损伤的肌电图诊断

臂丛神经损伤是一种常见损伤，多因外伤所致。臂丛神经的解剖结构复杂，损伤的类型比较复杂，肌电图(EMG)检测在臂丛神经损伤的诊断中非常重要，可从电生理角度为临床提供臂丛神经几个主要分支功能状态，明确损害类型及严重程度的客观资料。我科对2000年1月至2003年12月来我院就诊的臂丛神经损伤的50例患者进行常规(EMG)检测，并对部分手术的患者进行随访。现将结果报告如下。     

臂丛神经损伤的肌电图分析

臂丛神经损伤是和平时或战时都较常见的一种神经性损害,肌电图(EMG)对其有重要诊断价值[1].本文通过对50例外伤性臂丛神经损害患者的针电极EMG资料进行分析,以探讨其对辅助判断臂丛神经损伤的部位、程度、范围及预后等方面的价值.现将结果报道如下.     

臂丛神经损伤临床及肌电图诊断

目的:探讨臂丛神经损伤患者的临床特点及肌电图(EMG)诊断。方法:对2000年1月～2010年1月间经手术治疗的35例臂丛神经损伤患者进行临床及肌电图分析。结果:手术所见与神经电生理检测结果完全符合62.9%,基本符合为31.4%;EMG推测病变范围大多较手术所见损伤范围广。结论:综合临床、影像学资料,电生理测试可对臂丛神经损伤提出定性定位分类诊断,为临床诊断及手术提供可靠的依据。     

神经电生理检测对诊断臂丛神经损伤的体会

目的:探讨神经电生理检测对臂丛神经损伤患者的意义及提高阳性预测值的注意事项。方法:对我院2016年9月至2017年1月收治的11例臂丛神经损伤患者进行神经传导速度(NCV),肌电图(EMG)检查,结合临床表现,分析检查结果,计算阳性预测值。结果:神经电生理改变对臂丛神经损伤阳性预测值为72.7%(8/11例)。结论:神经电生理检测能够为臂丛神经损伤提供充分、客观的依据,如果在检测过程中充分注意到发病时间、病情严重程度等因素,可显著提高阳性预测值。     

运动神经元病的MEP、EMG、NCV与临床

目的：探讨联合应用运动诱发电位(MEP)、肌电图(EMG)和神经传导速度(NCV)对运动神经元病(MND)的诊断和鉴别诊断及分型的价值。方法：对47例MND患做MEP、EMG及NCV检查，EMG检查三个阶段以上的肌肉，其电生理变化与临床病程、分型进行比较。结果：47例MND患中，MEP异常34型，占72．3％，以中枢传导时间(CMCT)延长和波幅降低最多，占44．7％；EMG出现不同电生理变化的神经原性损害依次为运动单位时限增宽93．6％，运动单位减少89．4％，波幅增高74.5％，有纤颤、正相电位68．1％，且随病程延长纤颤、正相电位检出率逐渐降低；运动神经传导速度(MCV)测定，异常7例，占14．9％，感觉神经传导速度(SCV)测定，1条神经轻度减慢，1条波幅降低，异常率占3．3％。结论：MEP、EMG和NCV联合检查，可为MND的诊断、分型与颈椎病的鉴别诊断，提供客观依据。     

体感诱发电位与感觉神经动作电位对于臂丛神经(节前节后)损伤的诊断价值

本文报告4例臂丛神经损伤进行SEP,SNAP及手术的对比观察结果,臂丛神经损伤(节前/节后)与神经生理SEP和SNAP波幅降低或消失有关,提示:SEP与SNAP的共同应用对于臂丛神经损伤定位(节前/节后)有较高的应用价值。     

肌电图和运动神经传导速度检查诊断周围神经损伤

对136例周围神经损伤患者进行肌电图(EMG)与运动神经传导速度(MCV)分析。损伤神经支配的168块肌肉,EMG均为神经原性损害。166条受损神经MCV均有不同程度的减慢或缺失,其中周围神经完全断伤29.52％,严重损伤21.69％,中度损伤21.08％,轻度损伤27.71％。本文认为对周围神经损伤的定位和损伤程度的判断EMG和MCV是可靠和有效的方法。     

臀丛神经损伤的诊断

<正> 文中报告了684例臂丛神经损伤病例。结合术前、术后功能检查,并对各臂丛神经恨的机能支配及其临床意义进行了分析。提出了臂丛神经损防的诊断步骤:(1) 有无臂丛神经损伤;(2) 判断损伤部位;(3) 根、干、束、支的定位诊     

神经电生理技术在臂丛神经损伤定位诊断中的应用价值

目的:探讨神经电生理检查在臂丛神经损伤定位诊断中的应用价值。方法:选择2013年6月至2018年2月就诊于泉州市正骨医院的臂丛神经损伤患者65例,其中男46例,女19例。病程6 d～4年,年龄2个月～85岁,右侧臂丛神经损伤34例,左侧臂丛神经损伤31例,所有患肢分别进行运动传导速度(MCV)、末端潜伏期(LAT)、复合肌肉动作电位(CMAP),感觉传导速度(SCV)、感觉神经动作电位(SNAP)及尺神经运动F波检测,对其异常结果进行分析,观察神经损伤情况。同时用同心针电极对受损神经所支配的肌肉进行肌电图检查。结果:65例患者中,其中全臂丛损伤6例,臂丛(C5+C6根性)损伤7例,臂丛(C5根性)损伤6例,臂丛神经上中干损伤8例,臂丛神经上中下干损伤7例,臂丛神经上干损伤5例,臂丛神经束支部损伤20例,臂丛锁骨上下联合损伤6例。其中合并多发周围神经损害1例,合并尺神经肘段损伤1例,合并副神经损伤3例,膈神经损伤2例。结论:神经电生理检查可以提供臂丛神经五大分支(腋神经、肌皮神经、桡神经、正中神经、尺神经)的功能状态、受损程度及损伤部位,对临床诊断、治疗和预后判断起着重要作用。     

神经电生理检查在肌萎缩侧索硬化症中的应用

目的:观察神经电生理检查在肌萎缩侧索硬化症(amyotrophic lateral sclerosis,ALS)中的应用价值。方法:分别对28例临床确诊ALS、6例临床拟诊ALS、4例临床可能ALS患者进行4个区域的共8块肌肉肌电图(EMG)分析,四肢的磁运动诱发电位(MEP),上肢正中神经、尺神经、下肢胫神经F波检查,在双侧腓肠肌记录H波,四肢远端神经传导测定,包括运动传导速度(MCV)、感觉传导速度(SCV)、复合运动神经动作电位(CMAP)、感觉神经动作电位(SNAP)以及运动末梢潜伏期(DML)进行测定并分析,并与健康对照组30例进行比较。结果:临床确诊ALS的神经电生理测定各值异常均高于拟诊ALS和可能ALS(P<0.05),拟诊ALS和可能ALS组比较没有明显统计学差异。ALS组EMG异常率85%,MEP异常率72.4%,神经传导异常主要表现为CMAP降低36.2%,SCV基本正常,F波出波率下降33.3%,F波振幅增高26.3%,H波振幅增高26.3%。结论:EMG对ALS患者下运动神经元损害有定位诊断价值,EMG是ALS诊断的重要依据;MEP对ALS患者上运动神经元损害有诊断价值,但特异性不高;F波、H波对ALS患者上下神经元神经损害定位有补充诊断价值,神经传导测定用于ALS的鉴别诊断。     

Modulations of input-output properties of corticospinal tract neurons by repetitive dynamic index finger abductions

The goal of this study was to investigate how corticospinal tract neurons (CTNs) are modulated after repetitive dynamic muscle contractions. To address this question, changes of motor evoked potentials (MEPs) to transcranial magnetic stimulation and background EMG (B.EMG) activities were examined. Subjects were instructed to perform an isometric dynamic index finger abduction as accurately as possible under the target-force-matching tasks (10% or 30% MVC), while MEPs of a first dorsal interosseous (FDI) were elicited during performance of the task. After repetitive dynamic FDI contractions (100 trials), the following remarkable phenomena were observed: (1) both B.EMG activities and MEP amplitudes decreased in proportion to the number of trials, (2) these phenomena were most commonly observed in different conditions, i.e., different force levels and hands (preferred or non-preferred hands), and (3) after repetition of the tasks, the MEP amplitude/B.EMG (MEP/B.EMG) ratio became smaller. Decreases of B.EMG activities with reduction of MEP amplitudes and diminishing MEP/B.EMG ratio might suggest the occurrence of reorganization of input-output properties in CTNs for an efficient performance as a function of motor adaptation. Thus, we conclude that motor adaptation after repetitive dynamic muscle contractions probably occurs less specifically and due to susceptible modulations of spinal motoneurons reflected in the integrative functions of CTNs.     

神经电生理检查在运动神经元病中的诊断价值

目的:研究神经电生理检查在运动神经元病(MND))中的诊断价值。方法:分别对25例MND患者进行了磁刺激运动诱发电位(mMEP)、肌电图(EMG)、神经传导速度(NCV)、体感诱发电位(SEP)测定,并与健康对照组20例进行比较。结果:MND组mMEP皮层潜伏期和中枢运动传导时间(CMCT)均明显长于对照组;EMG神经原性损害占70％;NCV 30％患者异常;SEP未见明显异常。结论:mMEP结合EMG检查在MND的诊断和分型中具有重要价值。     

Corticospinal contributions to lower limb muscle activity during cycling in humans

The purpose of the current study was to investigate corticospinal contributions to locomotor drive to leg muscles involved in cycling. We studied 1) if activation of inhibitory interneurons in the cortex via subthreshold transcranial magnetic stimulation (TMS) caused a suppression of EMG and 2) how the responses to stimulation of the motor cortex via TMS and cervicomedullary stimulation (CMS) were modulated across the locomotor cycle. TMS at intensities subthreshold for activation of the corticospinal tract elicited suppression of EMG for approximately one-half of the subjects and muscles during cycling, and in matched static contractions in vastus lateralis. There was also significant modulation in the size of motor-evoked potentials (MEPs) elicited by TMS across the locomotor cycle (P < 0.001) that was strongly related to variation in background EMG in all muscles (r > 0.86; P < 0.05). When MEP and CMEP amplitudes were normalized to background EMG, they were relatively larger prior to the main EMG burst and smaller when background EMG was maximum. Since the pattern of modulation of normalized MEP and CMEP responses was similar, the data suggest that phase-dependent modulation of corticospinal responses during cycling in humans is driven mainly by spinal mechanisms. However, there were subtle differences in the degree to which normalized MEP and CMEP responses were facilitated prior to EMG burst, which might reflect small increases in cortical excitability prior to maximum muscle activation. The data demonstrate that the motor cortex contributes actively to locomotor drive, and that spinal factors dominate phase-dependent modulation of corticospinal excitability during cycling in humans.     

Further insight into the task-dependent excitability of motor evoked potentials in first dorsal interosseous muscle in humans

We have reexamined the contradictory evidence in which task-dependent excitation of motor evoked potentials (MEPs) in the first dorsal interosseous (FDI) muscle was stronger with increasingly more complex finger tasks than with individual finger movement tasks. In the first step of the experiment, based on previous findings, we investigated remarkable functional differences between intrinsic and extrinsic hand muscles during complex finger tasks (precision and power grip). During the performance of the tasks, the optimal stimulus intensity of the transcranial magnetic stimulation (TMS) was applied to the contralateral motor cortex. MEPs of the FDI, extensor carpi radialis (ECR), and flexor carpi radialis (FCR) muscles were recorded simultaneously with increased background EMG activity step by step in both tasks. The intensity threshold of TMS was lower in the precision grip. Furthermore, the MEP amplitudes of FDI muscle dependent on the background EMG activity were different between these two tasks, i.e., MEP amplitudes and regression coefficients in a precision grip were larger than those in a power grip. Although our results for MEP amplitude and threshold in the FDI muscle were similar to previous reported evidence, the different contributions of a synergistic muscle (in particular, the ECR muscle) during performance in these tasks was new evidence. Since there were no differences in cutaneous afferent effects on both tasks, corticomotoneuronal (CM) cells connected to FDI motoneurons seemed generally to be more active during precision than power gripping, and there were different contributions from synergistic muscles during the performance of these tasks. In the second part of the experiment, the results obtained from the complex tasks were compared with those from a simple task (isolated index finger flexion). MEP amplitudes, dependent on the background EMG activity during isolated index finger flexion, varied among subjects, i.e., the relationship between the MEP amplitude and the background EMG of the FDI muscle showed individual, strategy-dependent modulation. There were several kinds of individual motor strategies for performing the isolated finger movement. The present results may explain the previous contradictory evidence related to the contribution of the CM system during coordinated finger movement.     

Short interval intracortical inhibition and facilitation during the silent period in human

Following a suprathreshold transcranial magnetic stimulation (TMS) to the primary motor cortex (M1) during voluntary muscle contraction, a motor evoked potential (MEP) occurs in the target muscle followed by a silent period (SP) in the electromyographic (EMG) activities. The present study investigated how short interval intracortical inhibition (SICI) and intracortical facilitation (ICF) change during the SP. The time course of MEP and motor threshold during the SP were examined in the right first dorsal interosseous muscle. Using a triple-pulse protocol, SICI and ICF were tested at different times during the SP. The effects of different intensities of the conditioning stimulation (CS) for SICI and ICF were also investigated during the SP and at rest. During the SP, MEP was inhibited and motor threshold was increased, whereas MEP latency and background EMG level were same as those at rest. SICI decreased during the SP over a wide range of CS intensities. ICF increased at higher CS intensity. We conclude that SICI is suppressed and ICF is facilitated during the SP and the effects are separate from the interruption of voluntary drive.     

Handedness-related asymmetry in transmission in a system of human cervical premotoneurones

 The possibility was investigated that human handedness is associated with an asymmetrical cortical and/or peripheral control of the cervical premotoneurones (PreMNs) that have been shown to mediate part of the descending command to motoneurones of forearm muscles . Heteronymous facilitation evoked in the ongoing voluntary extensor carpi radialis (ECR) electromyographic activity (EMG) by weak (0.8 times motor threshold) stimulation of the musculo-cutaneous (MC) nerve was assessed during tonic co-contraction of biceps and ECR. Suppression evoked by stimulation of a cutaneous nerve (superficial radial, SR) at 4 times perception threshold in both the voluntary EMG and in the motor evoked potential (MEP) elicited in ECR by transcranial magnetic stimulation (TMS) was investigated during isolated ECR contraction. Measurements were performed within time windows or at interstimulus intervals where peripheral and cortical inputs may interact at the level of PreMNs. Results obtained on both sides were compared in consistent right- and left-handers. MC-induced facilitation of the voluntary ECR EMG was significantly larger on the preferred side, whereas there was no asymmetry in the SR-evoked depression of the ongoing ECR EMG. In addition, the suppression of the ECR MEP by the same SR stimulation was more pronounced on the dominant side during unilateral, but not during bilateral, ECR contraction. It is argued that (1) asymmetry in MC-induced facilitation of the voluntary EMG reflects a greater efficiency of the peripheral heteronymous volley in facilitating PreMNs on the dominant side; (2) asymmetry in SR-induced suppression of the MEP during unilateral ECR contraction, which is not paralleled by a similar asymmetry of voluntary EMG suppression, reflects a higher excitability of cortical neurones controlling inhibitory spinal pathways to cervical PreMNs on the preferred side. Received: 20 May 1998 / Accepted: 15 October 1998     

Corticospinal Facilitation Studied During Voluntary Contraction of Human Abdominal Muscles

Transcranial magnetic stimulation (TMS) of the human motor cortex was used to study facilitation of motor-evoked potentials (MEPs) in the rectus abdominis (RA) muscle, a trunk flexor, during voluntary activation. MEPs could be produced in the relaxed RA muscles of all six normal subjects studied. The MEPs had short latencies (18-22 ms) which are consistent with other studies suggesting a fast corticospinal input to the trunk muscles. Marked facilitation was observed in the MEPs when subjects were asked to produce graded levels of voluntary contractions. The two tasks used to produce voluntary contractions were a forced expiration during a breath-holding task (FEBH) and bilateral trunk flexion (BTF). Maximal voluntary EMG activity during the BTF task produced around 4.2 times more integrated EMG than during the FEBH task. Similarly the MEP amplitude at MVC was 2.3 times greater during BTF than FEBH. The pattern of MEP facilitation with increasing voluntary EMG was not linear and a maximal MEP amplitude was observed at a level of voluntary contraction around 30 % MVC in both tasks. There were some subtle differences in the pattern of facilitation in the two tasks. When TMS was applied to the right cortex only, MEPs were seen in both left and right RA muscles suggesting some ipsilateral corticospinal innervation. The latency of the right (ipsilateral) response was approximately 2 ms longer than the left. Comparison with studies in hand and leg muscles suggests that the facilitation pattern in RA may reflect a substantial degree of corticospinal innervation. Experimental Physiology (2001) 86.1, 131-136.     

Emotion facilitates action: a transcranial magnetic stimulation study of motor cortex excitability during picture viewing

Emotional stimuli capture attention, receive increased perceptual processing resources, and alter peripheral reflexes. In the present study, we examined whether emotional stimuli would modulate the magnitude of the motor evoked potential (MEP) elicited in the abductor pollicus brevis muscle by transcranial magnetic stimulation (TMS) delivered to the motor cortex. The electromyogram (EMG) was recorded from 16 participants while they viewed six blocks of pleasant, neutral, and unpleasant images; 36 TMS pulses at increasing intensities were delivered during each block. The TMS-induced MEP was reliably larger while participants viewed pleasant and unpleasant compared to neutral images. There were no differences in the pre-TMS EMG activity as a function of emotional stimuli. Thus, viewing arousing stimuli, regardless of valence, increased motor cortex excitability. Implications and directions for future research are discussed.