小儿注射性坐骨神经损伤的脊髓运动诱发电位诊断

目的利用肌电图常规电刺激器测定脊髓运动诱发电位（MEP）技术，建立小儿注射性坐骨神经损伤诊断的新方法。方法采用英国Medelec公司生产的MS6型肌电图机，刺激器采用本机所配刺激器，刺激电压250～300mv，脉宽0．5～1ms。刺激电极为表面鞍型电极。刺激部位：负极处于L1棘突间，正极处于其上方。刺激方式为单次手动触发。记录部位为健、患侧胫前肌群及腓肠肌群。记录电极采用2支单极针电极。结果7例患儿主要异常形式表现为：诱发波的振幅降低，潜伏时延迟。结论测定表明该方法具有直接测定损伤段神经，异常表现出现早等优点。     

50例小儿急性脊髓灰质炎的运动诱发电位研究

利用经皮电刺激大脑皮质及脊髓的运动诱发电位(MEP)技术,对50例急性脊髓灰质炎患儿的中枢及周围运动神经系统功能进行了研究。结果表明,患儿皮质刺激时的MEP异常率上、下肢分别为28％和85％;异常形式为阻滞、延迟和振幅降低,并首次提出本病存在周围神经传导异常,上、下肢异常率分别为2％和47％。     

肌萎缩侧索硬化症的经颅磁刺激运动诱发电位研究

目的:研究肌萎缩侧索硬化症(ALS)患者经颅磁刺激运动诱发电位(TMS-MEP)改变及与临床的相关性,了解其在ALS诊断和上运动神经元(UMN)损害评价中的作用。方法:对符合1998年修订的E1Escorial诊断标准的ALS患者40例、单纯下运动神经元(LMN)受累患者8例和健康对照34例进行双小指展肌、胫前肌TMS-MEP测定。MEP中枢性损害的判断标准为中枢运动传导时间(CMCT)延长、安静状态双侧皮层刺激MEP未引出或易化状态至少一侧皮层刺激MEP未引出,CMCT侧间差增大为可疑异常。所有ALS患者均用改良的MRC评分判断双侧小指展肌和胫前肌肌力,Ellis反射评分评估UMN受累程度,Norris评分和ALS功能评分量表(ALSFRS)评价疾病的严重程度,并与MEP改变做相关分析。结果:ALS患者小指展肌易化状态、安静状态CMCT、胫前肌易化状态CMCT分别为7.12±2.25、8.69±1.38、13.11±2.06ms,与对照组比较显著延长(对照组相应数值分别为6.26±0.97、8.10±1.22、12.30±1.11ms)。ALS患者TMS-MEP中枢性损害的出现率为62.5%,主要表现为CMCT延长和MEP引不出,分别占52.5%(21/40)和40%(16/40),如将CMCT侧间差增大者计入,则总异常率提高到72.5%。单纯LMN受累患者未见MEP中枢性异常。按诊断级别分组后,临床确诊、拟诊、实验室辅助拟诊和可能的ALS的MEP中枢性损害出现率分别为88.9%、81.8%、69.2%和42.9%,单纯CMCT侧间差增大而无其他异常仅见于辅助拟诊或可能的ALS患者。CM-CT与相应靶肌肌力无关(p>0.05),与相应肢体的Ellis评分显著正相关(r=0.272～0.391,p<0.05),与Norris评分和ALSFRS显著负相关(r分别为-0.418～-0.426和-0.352～0.429,p<0.05)。结论:对于ALS的早期诊断,TMS-MEP的敏感性欠高,但对于辅助拟诊或可能的ALS,MEP中枢性异常有助于UMN受累的确立。单纯CMCT侧间差增大可能发生于早期患者,有助于发现轻度或亚临床UMN病损。CMCT变化与UMN损害程度相一致,是UMN受累的客观评价指标,且在一定程度上反映患者肢体功能状态和疾病严重程度,但其能否用于病情监测,仍需进一步随访研究。     

神经电生理检查在脊髓亚急性联合变性中的诊断应用

目的探讨神经电生理检查在脊髓亚急性联合变性(SCD)中的诊断意义。方法回顾性分析42例临床确诊为脊髓亚急性联合变性患者的病例资料,统计磁共振(MRI)检查、神经电生理检查(包括体感诱发电位、运动诱发电位、视觉诱发电位、脑干听觉诱发电位、神经传导及针肌电图)、血清维生素B12水平、症状及体征等,将神经电生理异常率与MRI异常率进行比较。结果神经电生理异常35例,异常率83.3%,其中体感诱发电位、运动诱发电位、视觉诱发电位、脑干听觉诱发电位、神经传导及针肌电图诸项目均可出现异常;MRI异常23例,异常率54.8%。通过SPSS软件处理,符合Pearsonχ2检验,差异有统计学意义(P<0.05)。结论神经电生理检查可客观反映SCD病变部位,异常率高于MRI检查,并可进行定性诊断,在SCD疾病的早期诊断中具有重要价值。     

急性脑梗死运动诱发电位检测与临床相关性研究

目的 探讨急性脑梗死运动诱发电位变化特点与临床相关性.方法 94例患者均于入院当天行日常生活能力和临床神经功能缺损(MESSS)评分,并根据瘫痪程度进行分级,于入院3d内行MEP检查.结果 (1)病变部位不同,MEP的异常率不同.(2)MEP异常与病理征间无相关性.(3)MEP异常和MEP波形缺失与瘫痪程度、MESSS评分间具有正相关性,与BI评分具有负相火性,而皮质潜伏期和CMCT延长并不意味着患者病情严重.结论 MEP检查对判断脑梗死患者神经功能损伤严重程度具有重要意义.     

接触性热痛诱发电位在亚急性联合变性诊断中的应用

目的 应用接触性热痛诱发电位(CHEPs)技术研究亚急性脊髓联合变性(SCD)患者痛觉传导通路变化特点,探讨CHEPs在SCD中的应用价值,为其电生理诊断提供依据.方法 选取确诊型SCD患者20例和健康人34名,应用CHEPs刺激器,刺激水平为51℃,对C_7部位、上肢前臂掌侧前1/3处、下肢内踝及腰部进行刺激,记录点为Cz,记录诱发电位主要成分的潜伏期和波幅.分析周围神经Aδ纤维传导速度和中枢N波峰潜伏期、N-P波波幅,同时进行躯体感觉诱发电位(SEP)及感觉传导速度(SCV)测定并与CHEPs进行比较.结果 (1)健康对照组予以51℃刺激,CHEPs的引出率为100%.(2)患者组中存在痛温觉减退者,视觉模拟评分[VAS,上肢6.4(5.3～8.9)分,下肢5.7(2.8～8.8)分]低于健康对照组[上肢7.6(6.4～9.2)分,下肢6.9(5.7～9.1)分,Z=3.478、3.909,P＜0.01].(3)患者组上肢A8纤维传导速度(CV)为(9.77±4.28)m/s,下肢Aδ纤维CV为(8.19±0.91)m/s,与健康对照组[(12.87±1.40)m/s]比较,差异具有统计学意义(t=3.142、14.864,P＜0.01).患者组中上肢Aδ纤维CV减慢13例(65%),正中神经SCV减慢4例(20%);下肢Aδ纤维CV减慢19例(85%),胫神经SCV减慢12例(60%),A5纤维CV异常率高于SCV.(4)患者组下肢CHEPs异常者16例,而SEP异常者18例,两组间比较差异无统计学意义.结论 CHEPs能发现SCD痛觉传导通路异常部位和程度,较SCV敏感,可以作为辅助SCD电生理诊断的方便、客观的方法.     

急性脑血管病患者经颅电刺激运动诱发电位及体感诱发电位的临床研究

目的 :研究经颅电刺激运动诱发电位 (MEP)和体感诱发电位 (SEP)与急性脑血管病 (ACVD)患者功能状态的关系。方法 :对 5 4例有偏瘫体征的ACVD患者行MEP和SEP检查 ,同时作肌力和临床神经功能评分测定。结果 :ACVD病人MEP的异常率为88 9%,主要表现为MEP缺失 ,潜伏期延长 ,波幅降低或波形异常 ,中枢运动传导时间 (CMCT)延长 ,患者与健侧及对照组比较 ,有显著差异 (P <0 0 1)。MEP缺失者 ,瘫痪重 ;MEP可引出者 ,瘫痪程度轻 ,两者间差异显著 (P <0 0 1)。SEP的异常率为 42 6 %,表现为中枢传导时间延长和皮质波异常或消失 ,功能评分为重型者 ,异常率高 ;轻型者 ,异常率低。结论 :MEP可定量分析ACVD病人运动功能的缺损情况 ,结合SEP可提供更多的脑部信息     

运动神经元病患者胸锁乳突肌肌电图的特征

目的探讨运动神经元病(MND)患者胸锁乳突肌(SCM)肌电图的特征。方法回顾性分析461例MND患者及349例非MND患者的临床和肌电图资料。结果MND组SCM肌电图异常率(60.3%)显著高于非MND组(4.6%)(P<0.01);确诊级MND患者SCM肌电图的异常率(77.4%)明显高于其他诊断级(均P<0.01);MND组中,SCM肌电图的异常率(60.3%)低于上、下肢体肌肉的肌电图(93.2%、84.4%)(均P<0.001);MND患者SCM肌电图异常以自发电位(42.5%)和轻收缩时运动单位电位时限增宽(43.2%)最为常见;MND组有延髓症状者SCM肌电图的异常率(71.7%)明显高于无延髓症状者(54.3%)(P<0.05)。结论MND患者SCM肌电图异常率及其特异性高,为延髓肌受累的指征,有助于MND的诊断与鉴别诊断。     

39例多系统萎缩的神经电生理特点分析

目的:观察多系统萎缩(MSA)患者神经电生理改变,探讨神经电生理对MSA的诊断价值。方法:22例行肢体骨骼肌肌电图(EMG)和神经传导速度(NCV)检测,39例均行肛门括约肌肌电图(EAS-EMG)检测,35例行脑干听觉诱发电位(BAEP)检测,26例行下肢体感诱发电位(SEP)检测,10例行视觉诱发电位(VEP)检测。电生理检查结果与本科检查室正常值比较。结果:肢体骨骼肌EMG和NCV的异常率为36．4％,肛门括约肌EMG异常率为89。7％,均呈神经源性受损表现;诱发电位的异常出现率分别为:BAEP(57．1％)、SEP(34．1％)、VEP(21．4％)。结论:神经电生理检测对于MSA的早期诊断有一定的帮助,可提高诊断的准确性。     

脊髓刺激治疗危重肢体缺血的随机试验:技术与并发症

对120例危重肢体缺血患者随机进行药物治疗和药物+脊髓刺激(SCS)。 60例应用脊髓刺激器测定保肢及疼痛缓解情况。两治疗组平均疼痛缓解率均为50％。2年肢体存活率分别为52％(SCS)和46％(标准治疗)(P=0.47)。SCS组皮肤微循环测定的TcpO_2为中间     

Neurophysiological assessment of the motor and sensory spinal pathways in chronic spinal cord injury

Introduction of transcranial magnetic stimulation (TMS) has provided means to study non-invasively corticospinal functions in humans. The purpose of the present study was to obtain an objective evaluation of spinal cord functions in spinal cord injury (SCI) subjects using TMS, multichannel surface EMG and somatosensory-evoked potentials (SSEP). Multichannel surface EMG recording was performed during reinforcement manoeuvres and during vibratory tonic reflex. Twenty-five post-traumatic clinically incomplete (ambulatory, AMB, and non-ambulatory, nAMB) SCI subjects were studied and compared to a control group of seven subjects. After preliminary analysis of neurophysiological studies they were divided into four groups according to presence or absence of motor-evoked potentials (MEP) in response to TMS in muscles below the level of the lesion and according to their ability to ambulate. TMS was delivered at vertex at 100% intensity and recorded from the large muscles of the upper and lower limbs. Surface EMG was recorded during reinforcement manoeuvres (RM) in the leg muscles and EMG activity was scored. SSEP were recorded at T12, L2, L4 and SI spinous processes and at Cz' on the scalp following tibial nerve stimulation at popliteal fossa. The prevalence of EMG responses during RM was higher in group with present MEPs (AMB/MEP+ and nAMB/MEP+) than in the group without MEPs. The group with present MEPs also showed better preserved functions of the ascending tracts compared to subjects without MEPs. Groups with present MEPs had 5/10 normal, 2/10 abnormal and 3/10 absent cortical SSEPs, whereas groups without MEPs showed 1/11 normal, 4/11 abnormal and 6/11 absent cortical SSEPs. Sustained function of ascending tracts was also positively correlated with preserved ability to ambulate. It was concluded that TMS in combination with multichannel surface EMG monitoring and sensory evoked potentials may prove feasible in assessing the functional capacity of the spinal cord after spinal cord lesion.     

Electromyography detects mechanically-induced suprasegmental spinal motor tract injury: Review of decompression at spinal cord level

ObjectiveHerein, we report use of electromyography (EMG) to anticipate corticospinal conduction block, as defined by muscle-derived transcranial electrical motor evoked potential (TCE MEP) loss, during extradural spinal cord decompression.MethodsOne hundred and eighty-four patients underwent cervical (173) or thoracic (11) decompression. The same derivations were recorded for EMG and TCE MEP neuromonitoring. When highly repetitive, complex, and prolonged EMG discharges were identified in myotomes below the operated level (severe suprasegmentally-generated EMG discharges = severe SEDs), a report of possible spinal cord impact was made and a TCE MEP obtained. TCE MEP loss (with or without antecedent SEDs) was defined as >90% amplitude reduction compared to baseline recordings.ResultsSevere SEDs, seen in 15 cases, anticipated TCE MEP loss in 7/15. In 13/15 severe SED cases, manipulations near dura were the proximate cause. Interventions after TCE MEP loss included changed instrumentation, re-positioning, increased blood pressure, wake-up test, and surgical pause.ConclusionsSEDs can be identified during extradural spinal cord decompression. Severe SED occurrence is associated with a ∼50% risk of subsequent corticospinal conduction block.SignificanceAlthough SED occurrence does not provide specific information for lesions of the fast neurons of the corticospinal tract, SED surveillance during decompression at spinal cord level can supplement TCE MEP recording.     

磁刺激运动诱发电位在多发性周围神经病中的诊断价值

对１２例多发性周围神经病患者进行磁刺激运动诱发电位（ＭＥＰ）测定，同时测定感觉神经传导速度（ＳＣＶ）、运动神经传导速度（ＭＣＶ）及Ｆ波。结果发现，ＭＥＰ潜伏期异常率为７５％，高于ＳＣＶ（６６．７％）和ＭＣＶ（５８．２％）及Ｆ波（６０％）；至少有１项ＭＥＰ指标异常者１１例，占９１．７％。分析认为，ＭＥＰ异常率较高的原因在于它可以对包括神经根在内的周围神经全长进行测定。将ＭＥＰ各项指标综合分析可提高ＭＥＰ的阳性率。ＭＥＰ对周围神经病是一项有较大价值的辅助检查手段。     

Mechanomyographic response to transcranial magnetic stimulation from biceps brachii and during transcutaneous electrical nerve stimulation on extensor carpi radialis

Transcranial magnetic stimulation (TMS) elicits short latency excitatory responses in the target muscles, termed motor evoked potential (MEP). When TMS is delivered during a voluntary contraction, the MEP is followed by a period of silence called silent period (SP). These MEP parameters are in general recordable by electromyography (EMG). Mechanomyography (MMG) on the other hand is the mechanical counterpart of EMG. Thus, this study has been conducted to observe whether the MEP parameters from MMG signals showed similar trait of EMG recordings. Five normal healthy male subjects were included in this study. The subjects were required to perform right biceps brachii muscles contraction at diverse graded of load level at 5, 10, 20, 30, 40, 60, and 100% maximum voluntary contraction (MVC). MEPs by single pulse TMS on left hemisphere were obtained from both EMG electrode and MMG accelerometer at rest and at different levels of predetermined load level. MEP amplitude and area obtained both from EMG and MMG record were increased with the increase of muscle contraction with a maximum of 60% MVC. With increasing the level of contraction there was a shortening of onset latency and decreasing in the length of silent period in both EMG and MMG signals. We also recorded the EMG- and MMG-MEP from the right extensor carpi radialis muscle during transcutaneous electric nerve stimulation in order to observe neural changes in sensory stimulation from both EMG and MMG responses. The EMG-MEP was not visible in electrical artifact whereas it was obvious in MMG responses. In accordance with other study, this study showed that the voluntary contraction of biceps brachii muscle influenced the MEP parameter which are moreover obtainable by MMG even in electrical noise may provide insight for future study.     

Motor responses evoked by transcranial magnetic stimulation and peripheral nerve stimulation in the ulnar innervation in amyotrophic lateral sclerosis: the effect of upper and lower motor neuron lesion

We studied the upper (UMN) and lower motor neuron (LMN) innervations of 159 hands from 81 patients with amyotrophic lateral sclerosis (ALS). Eleven patients with various chronic LMN disorders causing weakness in the abductor digiti minimi (ADM) muscle served as LMN controls. Thirty healthy subjects served as normal controls. Cortical motor threshold, central conduction time (CMCT), and motor-evoked response amplitude (MEP) after transcranial magnetic stimulation (TMS) were studied, and the MEP/M wave ratio was calculated. The data was analyzed in the ALS subjects in groups defined by ADM muscle strength and by the presence or absence of clinical signs of UMN involvement.

CMCT was not increased in the ALS or LMN disease groups. The threshold was higher in limbs with both weak ADM muscles and UMN signs. The MEP/M wave amplitude ratio was increased in weak muscles in the ALS patients, notably in limbs with no UMN signs, and also in weak muscles in patients with other chronic LMN disorders. It was frequently decreased in strong muscles. There was no difference between bulbar-onset and limb-onset ALS groups, and there was no correlation between threshold and disease duration. We suggest that expressing the data as an index and utilising the MEP/M wave amplitude ratio as a variable is a sensitive method for detecting UMN abnormality in ALS in particular in early affected muscles.     

13例神经肌炎的临床及肌电图研究

目的:探讨神经肌炎的临床特点以及肌电图(EMG)、神经传导速度(NCV)的诊断价值。方法:分析13例神经肌炎临床表现、EMG、NCV结果。结果:13例患者均以肌肉受累为主要临床表现;11例并发有神经病变的症状及体征。13例患者NCV均有异常。所检测的104根神经NCV异常率为57.7%。F波异常率为26.9%。11例针极EMG呈神经源性与肌源性混合损害,2例呈神经源性损害。结论:EMG、NCV是有价值的电生理诊断方法。确诊神经肌炎需结合临床表现和EMG结果。     

Muscle imaging: mapping responses to transcranial magnetic stimulation with high-density surface electromyography

Representations of different body parts or muscles in the human primary motor cortex overlap extensively. At the effector level, most muscles are surrounded by and overlap with several neighbours as well. This hampers the assessment of excitability in individual muscles with transcranial magnetic stimulation (TMS), even if so-called "focal" stimulating coils are used. Here we used a novel mapping paradigm based on high-density surface electromyography (HD-sEMG) to investigate the spatial selectivity of TMS in the forearm musculature. In addition, we tested the hypothesis that selective stimulation can be improved by a voluntary background contraction of the target muscle. We mapped and compared the topographies of motor evoked potential (MEP) amplitudes during rest and during background contractions of two forearm muscles (extensor carpi radialis and extensor digitorum communis). The MEP topographies were also compared to the amplitude topography of voluntary EMG. The results indicate that under many conditions a large proportion of the MEP activity recorded at the surface originated from the target muscle's neighbours. There was a systematic relationship between TMS intensity and the topographic distribution of MEP responses during voluntary contraction. With increasing stimulus intensity, the MEP topography deviated increasingly more from the topography of voluntary EMG. We conclude that when standard EMG montages are used, the recorded MEPs are not necessarily evoked in the target muscle alone. Stimulation during a voluntary background contraction of the target muscle may enhance the selectivity of TMS. It however remains essential to use stimulus intensities as low as possible, to minimize the contribution of surrounding non-target muscles to the MEP.     

MEP latency shift after implantation of deep brain stimulation systems in the subthalamic nucleus in patients with advanced Parkinson's disease.

Deep brain stimulation (DBS) into the subthalamic nucleus (STN) is a highly effective treatment for advanced Parkinson's disease (PD). The consequences of STN stimulation on intracortical and corticospinal excitability have been addressed in a few studies using transcranial magnetic stimulation (TMS). Although excitability measurements were compared between the STN stimulation OFF and ON condition, in these experiments, there are no longitudinal studies examining the impact of electrode implantation per se on motor excitability. Here, we explored the effects of STN electrode implantation on resting motor thresholds (RMT), motor evoked potential (MEP) recruitment curves, and MEP onset latencies on 2 consecutive days before and shortly after STN surgery with the stimulator switched off, thus avoiding the effects of chronic DBS on the motor system, in 8 PD patients not taking any dopaminergic medication. After surgery, RMT and MEP recruitment curves were unchanged. In contrast, MEP onset latencies were significantly shorter when examined in relaxed muscles but were unchanged under preactivation. We hypothesize that postoperatively TMS pulses induced small currents in scalp leads underneath the TMS coil connecting the external stimulator with STN electrodes leading to inadvertent stimulation of fast-conducting descending neural elements in the vicinity of the STN, thereby producing submotor threshold descending volleys. These "conditioning" volleys probably preactivated spinal motor neurons leading to earlier suprathreshold activation by the multiple corticospinal volleys produced by TMS of the motor cortex. These TMS effects need to be considered when interpreting results of excitability measurements in PD patients after implantation of STN electrodes.     

Impaired facilitation of motor evoked potentials in incomplete spinal cord injury

Objectives To improve the diagnosis of damaged spinal motor pathways in incomplete spinal cord injury (iSCI) by assessing the facilitation of lower limbs motor evoked potentials (MEP). Methods Control subjects (n = 12) and iSCI patients (n = 21) performed static and dynamic isometric foot dorsiflexions. MEPs induced by transcranial magnetic stimulation and EMG background of tibialis anterior muscle (TA) were analyzed. Static and dynamic muscle activation was performed at comparable levels of maximal voluntary contraction (MVC). The influence of the motor tasks on the excitability and facilitation of MEPs was compared between controls and iSCI patients. Results In the controls an increased facilitation of TA MEP at lower levels of dynamic compared with static activation (10–20% MVC) could be shown. At matched EMG background level the MEP responses were significantly increased. In the iSCI patients at a comparable level of TA activation the MEP responses were significantly reduced and 3 different patterns of MEP responses could be distinguished: i) preserved increment of TA MEP in the dynamic motor task, ii) unchanged MEP size in the dynamic and static motor task, and iii) elicitable MEPs in the dynamic motor task,which were abolished in the static motor task. Conclusions Static and dynamic motor tasks have different effects on TA MEP facilitation. The task–dependent modulation of TA MEPs is comparable to that described for upper limb muscles. Complementary to the MEP delay this approach allows for an estimation of the severity of spinal tract damage. The task–dependent modulation of TA MEPs is an additional diagnostic tool to improve the assessment and monitoring of motor function in iSCI.     

Motor evoked potentials following cervical electrical stimulation in brachial plexus lesions

The diagnostic relevance of recording motor evoked potentials (MEPs) after electrical stimulation of the cervical region, as compared with conventional needle electromyography (EMG), was evaluated in 26 patients with brachial plexus (BP) damage of different aetiology, severity and topography. MEP abnormalities (absence or latency increase) were observed in at least one muscle of all the patients, with a global incidence of 61.5% of the muscles examined. Neurogenic EMG signs were present in all but one patient with an incidence of 62.2% of the muscles examined. Combining the two methods, the global incidence of abnormalities rose to 69.9%. MEP abnormalities were consistent with the clinical topography and severity of BP lesions and were fairly parallel with EMG findings. Recording MEPs after percutaneous electrical stimulation of the cervical region may be regarded as a rapid, non-invasive method for quantitative electrophysiological assessment of BP damage.