无痛性经颅大脑皮层电刺激的运动诱发电位及其临床应用

方法学与安全性 1980年，Merton与Morton用电容充-放电武电刺激器经颅刺激人运动皮层，在手肌引出运动诱发电位(MEP)。后因被认为存在头皮疼痛问题，Barker于1985年开发的磁刺激器引起人们更大兴趣。     

症状性颈动脉粥样硬化性狭窄患者经颅电刺激运动诱发电位的研究

目的：探讨经颅电刺激运动诱发电位(MEP)对症状性颈动脉粥样硬化性狭窄的诊断价值。方法：对32例颈动脉粥样硬化狭窄患者和20例正常人行经颅电刺激MEP检查,评价狭窄程度与MEP的关系。结果：症状性颈动脉粥样硬化患者电刺激狭窄侧大脑皮层手区与对侧上肢记录MEP的潜伏期和中枢传导时间(CMCT)较正常对照组和健侧延长(P＜0．05)；对侧下肢CMCT较正常对照组和健侧延长(P＜0．05)。结论：MEP异常程度与临床病情轻重和病变部位密切相关,提示MEP能客观反映颈动脉狭窄患者中枢运动传导通路亚临床受损的情况,具有定量的价值。     

经颅电刺激在卒中后运动康复领域的研究进展

由脑卒中造成的神经性损伤是目前导致运动功能障碍的主要病因之一,为社会和患者家庭带来了巨大的精神和经济负担。结合经颅电刺激的运动康复疗法为改善患者运动功能障碍、提高生活质量提供一种重要的治疗方式。经颅电刺激是一种无痛、非侵入式脑刺激方法,能够调节神经元胞内钙离子浓度、增强突触可塑性、调制神经放电频率、改变皮层兴奋性,从而实现对大脑神经活动的调控。回顾经颅电刺激的神经机制,在科研临床应用中的参数设置,以及安全性等问题,总结其在运动功能康复方面的成果以及目前亟待解决的问题。     

经颅电刺激对大鼠脑梗死后运动功能恢复的影响

目的 :观察经颅皮层电刺激治疗对大鼠脑梗死后运动功能恢复的作用。方法 :选择12 0只SD成年雄性大鼠制作大脑中动脉闭塞 (MCAO)模型 ,将大鼠随机分为治疗组和对照组各 6 0只 ,治疗组在术后 3天给予经颅电刺激治疗 ,对照组术后不进行治疗 ,于术后第 1、2、3、4、5、6周末 ,分别以横木行走试验 (BWT)及运动诱发电位为指标评价大鼠运动功能恢复情况。结果 :经颅磁刺激治疗的大鼠 ,运动功能较对照组明显改善 (P <0 .0 1)。第 6周末治疗组患侧MEP波幅与潜伏期基本恢复正常 ,而对照组患侧MEP波幅仅恢复到 73.5 % ,潜伏期仍有所延长 ,两组相比有显著差异 (P <0 .0 5 )。结论 :经颅电刺激可以促进急性脑梗死大鼠瘫痪肢体运动功能的恢复 ,其机理可能与电刺激直接兴奋大脑皮层的运动中枢有关     

经颅磁刺激运动诱发电位和体感诱发电位对HMSN的诊断价值

目的:了解遗传性运动感觉性神经病(HMSN)的经颅磁刺激运动诱发电位(MEP)和体感诱发电位(SEP)的变化。方法:对一家三代HMSN的12例患者和1例无症状者进行这二项检查。结果:MEP和SEP的异常率分别为92.3％,84.6％,结论:绝大多数HMSN患者的MEP和SEP均异常。     

无痛性经颅大脑皮层电刺激的运动诱发电位及其临床应用

1980年，Merton用电容充一放电式电刺激器经颅刺激人运动皮层，在手肌引出运动诱发电位（MEP）。后因被认为存在头皮疼痛问题，Barker于1985年开发的磁刺激器引起人们更大兴趣。     

经颅电刺激技术用于运动表现提升的研究进展

经颅电刺激(TES)包括经颅直流电刺激、经颅交流电刺激和经颅随机噪声刺激,是一种非侵入的脑刺激技术。通过不同尺寸的电极将特定模式的低强度电流作用于特定的脑区,调节大脑皮质神经活动和/或兴奋性,增强大脑与神经、肌肉的连接,达到改善运动表现的作用。目前TES技术正在实现从实验室研究到运动科学应用研究的转变。首先阐述TES作用于大脑皮质的神经机制,着重评述近20年来TES在人类运动表现提升方面的研究进展,包括身体平衡、耐力表现、运动疲劳、肌肉力量和运动学习能力等5个方面;然后综述TES在脑网络功能连通性中应用的相关研究,并探讨该领域对TES改善运动表现的重要意义; 最后对TES在运动表现提升中的应用研究进行展望。     

经颅磁刺激对帕金森氏病患者的运动诱发电位的研究

目的： 本研究主要通过经颅磁刺激(TMS)检测帕金森氏病 (PD) 患者的运动诱发电位（MEP）,总结PD患者的MEP特点,探讨PD患者的运动皮质兴奋性。方法：选取健康志愿者20例作为正常对照组（A组）,男12例,女8例,年龄52-79岁,平均(62.3±16.7)岁。通过TMS检测左右两侧MEP,作左右侧比较。选取2007年5月-8月浙江大学医学院附属第二医院神经内科住院或门诊的PD患者共21例（B组）,均症状左右不对称,男12例,女9例,年龄46-80岁,平均(63.3±16.7)岁,按症状轻重程度比较MEP,且将PD组与正常组比较。结果：正常对照组左右侧MEP参数无显著差异。PD组与正常对照组相比,静息运动阈值（RMT）降低,波幅（Amp）升高,皮质潜伏期（CL）缩短,有显著差异,中枢运动传导时间（CMCT）改变无显著差异。PD症状重侧与轻侧相比较,重侧的RMT更低,有显著差异,AMP、CL、CMCT改变无显著差异。结论： PD患者的运动皮质兴奋性增高,且与症状严重程度相关。利用PD患者的MEP特点有助于辅助诊断,有助于评估症状严重程度,以RMT敏感性最高。     

经颅磁、电刺激运动诱发电位的安全性研究

经颅磁、电刺激运动诱发电位的安全性对比研究一直成为国内外有关学者所重视及争议的问题。本文作者通过动物实验及近数年的临床实践,采用上述两种运动诱发电位进行了动态观察及对比分析,认为如果按规定各参值进行临床检测并在选择病例中注意其适应症及禁忌症,则是安全的;但个别特殊病例则须结合机体状态进行分析后再行检测。     

帕金森病患者治疗前后运动诱发电位的临床研究

目的：观察帕金森病（PD）患者经重复经颅磁刺激（rTMS）和恩他卡朋添加治疗前后运动诱发电位（MEP）的改变。方法：用rTMS及恩他卡朋添加治疗PD患者,记录治疗前后患者UPDRS评分,并行运动诱发电位检查。结果：经rTMS及恩他卡朋添加治疗后,PD患者UPDRS评分较治疗前明显改善（P〈0．05）,其RMT明显增高,CL、CSP明显延长,差异有统计学意义（P〈0．05）。结论：MEP有助于PD的诊断、治疗及疗效观察。     

Influence of electrode impedance on threshold voltage for transcranial electrical stimulation in motor evoked potential monitoring

Motor potentials evoked by transcranial electrical stimulation (TES) are used for monitoring the motor pathways, with emphasis on the spinal cord and brainstem. The stimulus voltage threshold is the voltage below which no motor response can be elicited. It has frequently been used as a monitoring parameter. However, its value can be limited, because it is affected by the impedance of the stimulus electrode. For example, the voltage threshold can change owing to formation of oedema of the scalp. The relationship between the TES voltage threshold and the electrode impedance of different electrode types was studied and discussed in the context of neuromonitoring: 323 impedance and voltage threshold pairs were studied, and TES was performed with dics cup EEG electrodes (six), corkscrew electrodes (type I: seven, type II: eight), multiple EEG needle electrodes (16) and a large needle electrode Cz′ (anode) together with a ground strip over the forehead (cathode) (286). The study found the voltage threshold to be strongly dependent on electrode impedance when the impedance was higher than 460 Μ (correlation: R²=0.87; p<0.001). Below 460Ω, which included 91% of the category with the largest electrode surfaces, 25% of the multiple EEG electrodes and 75% of type II corkscrew electrodes, no significant correlation (R²=0.0064; p=0.15) was found. It was concluded that the correlation between the TES voltage threshold and electrode impedance can be markedly reduced by using TES electrodes with large contact surfaces, resulting in limit values for these parameters. This also may improve the reliability of TES motor evoked potential monitoring.     

中老年人脑白质疏松症的电刺激运动诱发电位研究

目的 :探讨电刺激运动诱发电位在中老年人脑白质疏松的临床应用价值。方法 :用大脑皮层电刺激仪刺激大脑上、下肢皮层运动区及颈椎7、胸椎1 2 棘突的相应皮肤 ,在大鱼际肌及胫前肌记录相应的运动诱发电位 (MEP) ,分别对 30例脑白质疏松的中老年人和 30例无白质疏松的对照组进行测定。结果 :脑白质疏松MEP的异常率 37% ,和正常人比较有显著性差异 (χ2 =9 79,P <0 0 1) ,其异常形式有 :中枢运动传导时间 (CMCT)延长 ,MEP潜伏期 (PL)延长 ,波幅增大和波形消失。下肢CMCT和PL延长与对照组比较有显著差异 (t=11 8,P <0 0 1)。结论 :MEP客观反映了脑白质疏松中老年人的运动传导功能 ,对判断亚临床锥体束损害有实用价值。     

Transcranial direct current stimulation modulates motor responses evoked by repetitive transcranial magnetic stimulation

Introduction

Repetitive transcranial magnetic stimulation (rTMS) and transcranial direct current stimulation (tDCS) are non-invasive techniques able to induce changes in corticospinal excitability. In this study, we combined rTMS and tDCS to understand possible interactions between the two techniques, and investigate whether they are polarity dependent.

Materials and methods

Eleven healthy subjects participated in the study. Each patient underwent both anodal and cathodal conditioning tDCS in two separate sessions; brief 5 Hz-rTMS trains were delivered over the primary motor cortex at an intensity of 120% the resting motor threshold (RMT) before tDCS (T0), immediately after (T1) and 10 min after current offset (T2). We then analysed changes induced by cathodal and anodal tDCS on TMS variables.

Results

Our results showed that in both anodal and cathodal sessions, the motor evoked potential (MEP) amplitude increased significantly in size before stimulation (T0). Conversely, after anodal tDCS, the MEP facilitation measured at T1 and T2 was absent, whereas after cathodal tDCS it was preserved.

Conclusions

Our findings provide new direct neurophysiological evidence that tDCS influences primary motor cortex excitability.     

Facilitation of motor evoked potentials in the anterior tibial muscle by repetitive subthreshold electrical stimulation

Subthreshold electrical stimulation with an intensity less than the threshold for evoking M-waves is applied repetitively to the common peroneal nerve via surface electrodes. The stimulation intensity is varied by adjusting the pulse width from 0 to 240 μs, while the pulse interval (40 ms) and current amplitude are kept constant. Single magnetic stimuli are applied to the motor cortex using a circular coil. Motor evoked potentials are recorded from the anterior tibial muscle in six normal subjects for various subthreshold stimulation intensities. Signal processing (filtering in the time and frequency domains) removes the artifact caused by the subthreshold electrical stimulation from the motor evoked potential. Statistically significant motor evoked potential facilitation (p<0.05) is observed for pulse widths ranging from 72 to 240 μs in all the tested subjects. A pulse width corresponding to 90% of the electrical threshold facilitated the motor evoked potential in five of the six subjects.     

MEP在吉兰--巴雷综合征患者中的应用价值

目的：探讨磁刺激运动诱发电位(MEP)在吉兰-巴雷综合征(GBS)中的诊断价值。方法：对20例GBS患者进行磁刺激MEP检测，分别刺激皮层、CV6—7、T12、L4—5、Erb点、肘部及胭窝以测定中枢及周围神经传导时间，并以20例健康正常人作对照。结果：GBS患者中枢及周围神经传导时间明显长于对照组，MEP异常率为85％。结论：GBS患者磁刺激MEP检测时中枢神经及周围神经传导时间延长，MEP阳性率高。MEP对GBS的早期诊断有重要价值。     

经颅磁刺激对帕金森病模型大鼠运动诱发电位潜伏期的研究

目的：通过对帕金森病（PD）模型大鼠经颅磁刺激（TMS）运动诱发电位（MEP）皮层潜伏期（Lat）的测值以了解其随病情发展的变化情况。方法：健康雄性（SD）大鼠40只,随机分为2组：①PD模型组26只,②对照组（生理盐水组）14只。选取右侧黑质致密部（substantia nigra pars compacta,SNc）与中脑腹侧背盖（ventra tegmental area,VTA）为手术靶点,PD模型组注射6一羟基多巴胺（6-OHDA）制备PD动物模型,对照组注射同等体积的生理盐水。于注射前、注射后第1周、第3周末分别行双下肢TMS-MEP检查。结果：术后1周,PD组鼠左下肢Lat较对照组缩短（P〈0．05）,PD组自身左右侧TMS-MEP比较,左下肢Lat较右下肢缩短（P〈0.05）;术前、术后第1周末、术后第3周末PD组大鼠左下肢Lat进行性缩短（P〈0.01）,PD组大鼠右下肢及对照组大鼠左侧及右侧下肢Lat皆无显著变化（P〉0.05）。结论：PD模型大鼠损毁侧皮层兴奋性增加,且与症状严重程度有关。PD模型大鼠病情越重、病程越长,Lat缩短越明显。     

脑梗死患者的运动及体感诱发电位研究

目的：研究脑梗死患者的运动诱发电位（ＭＥＰ）及体感诱发电位（ＳＥＰ）改变。方法：对３０便脑梗死患者在急性期行经颅磁刺激ＭＥＰ检测,对其中２０例同时行电刺激ＳＥＰ检测,１０例患者２月后复查ＭＥＰ,并以３０例健康者作为正常对照组。结果：急性期ＭＥＰ的异常率为９３％,主要表现为皮层ＭＥＰ消失,中枢运动传导时间（ＣＭＣＴ）延长,波形异常及阈刺激强度增高。ＳＥＰ的异常率为３０％,表现为皮层波的缺失及中枢传导时间延长。复查ＭＥＰ有９例明显改善。结论：对于脑梗死的诊断,ＭＥＰ较ＳＥＰ敏感,但将ＭＥＰ与ＳＥＰ联合应用,可从不同的两个侧面反映运动及感觉功能受损的情况,弥补了ＣＴ仅能提供颅内解剖学改变而不能反映功能状态的不足。     

Improved neuromonitoring during spinal surgery using double-train transcranial electrical stimulation

Motor evoked potentials (MEPs) evoked by transcranial electrical stimulation (TES) have become an important technique for monitoring spinal cord function intra-operatively, but can fail in some patients. A new technique of double-train stimulation is described. A multipulse transcranial electrical stimulus is preceded by a preconditioning pulse train that leads to larger MEP responses. An MEP monitoring system was adapted for double-train transcranial stimulation (DTS). MEP responses from 160 anterior tibial muscles obtained by double-train stimulation were analysed. All patients received propofol/remifentanil/O₂/N₂O anaesthesia. Fifty-two (83%) out of 63 single-train tibial MEPs with response amplitudes below 100 μV were magnified to over 100 μV, with an inter-train (inter-stimulus) interval ITI=10–35 ms. These 63 amplitudes were magnified by an overall logarithmic mean factor of 15.5. For 97 MEPs with amplitudes above 100 μV, the logarithmic mean facilitation factor was 2.4. It was concluded that double-train TES stimulation can markedly facilitate responses to a single stimulus train (STS). The facilitation appears to be most effective when the responses to STS would otherwise be small or absent. This preconditioning stimulation technique is therefore useful when an STS leads to responses that are too small for effective monitoring.