Motor recovery following stroke: a transcranial magnetic stimulation study.

OBJECTIVES: To verify the usefulness of early recording of motor evoked potentials (MEPs) in predicting motor outcome after stroke and to investigate the neural mechanisms underlying functional recovery following stroke. METHODS: We performed a comparative analysis of the behaviour of motor responses evoked by transcranial magnetic stimulation (TMS) of the ipsilateral and contralateral motor cortex in the affected and unaffected thenar muscles of 21 consecutive patients with acute stroke. RESULTS: According to the behaviour of MEPs in the affected muscles, patients could be divided into 3 groups: (a) 10 subjects with absent responses to TMS of both the damaged and undamaged hemisphere, whose motor recovery was poor and related to the size of MEPs on the normal side; (b) 5 subjects with larger MEPs upon TMS of the ipsilateral (undamaged) than of the contralateral (damaged) cortex, whose good recovery possibly resulted from the emergence of ipsilateral pathways; (c) 6 subjects with larger MEPs in the affected than in the unaffected muscles, whose good recovery was possibly subserved by alternative circuits taking over cortical deafferentation. CONCLUSIONS: Early MEP recording in acute stroke provides useful information on the clinical prognosis and the different mechanisms of motor recovery.     

Motor representation in patients rapidly recovering after stroke: a functional magnetic resonance imaging and transcranial magnetic stimulation study

OBJECTIVE: Neuroimaging studies have suggested an evolution of the brain activation pattern in the course of motor recovery after stroke. Initially poor motor performance is correlated with an recruitment of the uninjured hemisphere that continuously vanished until a nearly normal (contralateral) activation pattern is achieved and motor performance is good. Here we were interested in the early brain activation pattern in patients who showed a good and rapid recovery after stroke. METHODS: Ten patients with first-ever ischemic stroke affecting motor areas had to perform self-paced simple or more complex movements with the affected or the unaffected hand during functional magnetic resonance imaging (fMRI). The location and number of activated voxels above threshold were determined. To study possible changes in the cortical motor output map the amplitude of the motor evoked potentials (MEP) and the extent of the excitable area were determined using transcranial magnetic stimulation (TMS). RESULTS: The pattern of activation observed with movements of the affected and the unaffected hand was similar. In the simple motor task significant (P<0.05) increases were found in the primary motor cortex ipsilateral to the movement, the supplementary motor area and the cerebellar hemisphere contralateral to the movement during performance with the affected hand compared to movements with the unaffected hand. When comparing simple with more complex movements performed with either the affected or the unaffected hand, a further tendency to increased activation in motor areas was observed. The amplitude of MEPs obtained from the affected hemisphere was smaller and the extent of cortical output maps was decreased compared to the unaffected hemisphere; but none of the patients showed MEPs at the affected hand when the ipsilateral unaffected motor cortex was stimulated. CONCLUSIONS: Despite a rapid and nearly complete motor recovery the brain activation pattern was associated with increased activity in (bilateral) motor areas as revealed with fMRI. TMS revealed impaired motor output properties, but failed to demonstrate ipsilateral motor pathways. Successful recovery in our patients may therefore rely on the increased bilateral activation of existing motor networks spared by the injury.     

The combination of neuronavigation with transcranial magnetic stimulation for treatment of opercular gliomas of the dominant brain hemisphere

Objective

The objective of this study is to investigate the application of transcranial magnetic stimulation combined with neuronavigation for preoperative mapping of the language area in neurosurgical interventions on the opercular area of the dominant hemisphere.

Methods

Five patients were operated upon gliomas in the opercular area. For localization of the speech area a transcranial magnetic stimulator MEDTRONIC-MagPro was used. BrainLAB-VectorVision Neuronavigation system was utilized for precise planning of the operative approach.

Results

Gross total resection was achieved in all patients. Three-month postoperative follow-up was done. Three of the patients had a transient postoperative motor aphasia which resolved within 1 month.

Conclusion

This method is useful for preoperative localization of the speech area, as well as preoperative planning of the operative approach and intra-operative planning of the direction of brain retraction and operative corridor.     

Efficacy of repetitive transcranial magnetic stimulation in depression: A review of the evidence

Repetitive transcranial magnetic stimulation (rTMS) is a novel treatment in psychiatry. We reviewed all published evidence on the efficacy of this treatment option in depressive disorders. An extensive electronic and manual search for eligible research reports identified only 12 studies that met the predetermined criteria for inclusion. rTMS was administered differently in most studies, and patient characteristics varied widely. A formal meta-analysis of the studies was thus not possible. Instead, we conducted a qualitative evaluation of the included studies. The antidepressive efficacy was not consistent, and where efficacy was demonstrated, it was modest in most studies. Some patients had good but transient responses to rTMS. Treatment gains were not maintained beyond the treatment period. Comparisons with electroconvulsive therapy (ECT) indicated the superiority of ECT. More, larger and more carefully designed studies are needed to demonstrate convincingly a clinically relevant effect of rTMS. We conclude that there is insufficient evidence for rTMS as a valid treatment for depression at present.     

重复经颅磁刺激对抑郁症患者磁共振波谱和疗效的影响

目的 探讨重复经颅磁刺激(rTMS)治疗抑郁症患者的疗效及可能机制. 方法 选择自2012年8月至2014年7月在全军精神疾病防治研究所住院的抑郁症患者70例,所有患者均符合美国精神障碍诊断与统计手册第4版诊断标准.按照随机数字表法将患者随机分为研究组(n=36)和对照组(n=34),2组患者均接受盐酸文拉法辛缓释片(75 mg/片)治疗.研究组同时联合10Hz rTMS作用于左侧背外侧前额叶(DLPFC)治疗4周,对照组给予rTMS伪刺激.治疗前后采用多体素磁共振质子波谱(1H-MRS)检测患者前额叶和丘脑N-乙酰基天门冬氨酸(NAA)、胆碱复合物(Cho)与肌酸复合物(Cr)含量.采用汉密尔顿抑郁量表(HAMD)于治疗前、治疗4周评估临床症状和疗效. 结果 (1)研究组治疗前左侧前额叶、左侧丘脑NAA/Cr值分别为1.51±0.34、1.36±0.29,治疗后分别升高至1.71±0.42、1.54±0.34,差异有统计学意义(P＜0.05).对照组双侧前额叶、双侧丘脑的NAA/Cr值、Cho/Cr值治疗前后差异均无统计学意义(P＞0.05).(2)研究组、对照组治疗前HAMD评分分别为32.3±8.8、31.8±8.5,治疗后降低为12.3±4.7、15.2±5.0,差异均有统计学意义(P＜0.05).研究组治疗前后的HAMD评分差值大于对照组,差异有统计学意义(P＜0.05).(3)治疗后,研究组显效率为80.6％(29/36)、治愈率为27.8％(10/36),对照组显效率为50.0％(17/34)、治愈率为5.9％(2/34),2组间显效率和治愈率的差异均有统计学意义(P＜0.05).(4)研究组盐酸文拉法辛缓释片平均治疗剂量为(136.6±28.4)mg/d、最大剂量为(175.0±35.6)mg/d;对照组平均治疗剂量为(162.4±32.2)mg/d、最大剂量为(216.2±40.3)mg/d;组间差异均有统计学意义(P＜0.05). 结论 10 Hz rTMS联合盐酸文拉法辛缓释片可以调节抑郁症患者前额叶和丘脑的神经生化代谢,进而改善抑郁症状,降低抗抑郁药物使用剂量.     

Left versus right repetitive transcranial magnetic stimulation in treating major depression: A meta-analysis of randomised controlled trials

Although the majority of randomised controlled trials suggest that major depressive disorder (MDD, major depression) and treatment-resistant depression can be effectively treated by applying either high- (HF) or low-frequency (LF) repetitive transcranial magnetic stimulation (rTMS) to the left and right dorsolateral prefrontal cortex (DLPFC), respectively, it is not clear which rTMS approach is more effective or safer. This systematic review and meta-analysis was conducted on randomised controlled trials on HF and LF rTMS applied to the left and right DLPFC, respectively, for the treatment of MDD. Eight randomised controlled trials composed of 249 patients were selected to compare the effects of LF (≤1 Hz) rTMS over the right DLPFC to HF (10–20 Hz) rTMS over the left DLPFC. The therapeutic effects of both approaches were similar (odds ratio (OR) = 1.15; 95% confidence interval = 0.65–2.03). Dropout analysis based on only two studies was insufficient to draw a conclusion on the tolerability of LF rTMS. The pooled examination demonstrated that both rTMS methods were equally effective therapies for MDD. However, considering that LF right-sided rTMS produces fewer side effects and is more protective against seizures, its clinical applicability shows greater promise and should be explored further.     

The effects of repetitive transcranial magnetic stimulation on depressive symptoms and the P300 event-related potential

Changes in the Hamilton Depression Rating Scale and the P₃₀₀ auditory event-related potential were assessed in 10 patients with depression before and after a treatment course of five daily sessions of 10?Hz repetitive transcranial magnetic stimulation (rTMS) over the left prefrontal cortex. The patients were initially randomly allocated either to an active or a placebo rTMS treatment. All patients received both types of treatment separated by an interval of 4?weeks. The median Hamilton score decreased by 7 points following active rTMS and by 1?point after sham (p=0.075). Active rTMS was associated with a significant increase in the P₃₀₀ amplitude compared with sham (p=0.02). There was no correlation between changes in P₃₀₀ measurements and the Hamilton scores after active treatment. We conclude that five daily sessions of left prefrontal rTMS treatment is not of sufficient duration to make a significant improvement in depressive symptoms.     

重复经颅磁刺激治疗伴躯体疼痛抑郁症患者的疗效观察

目的探讨重复经颅磁刺激（rTMS）治疗伴有躯体疼痛的抑郁症患者的临床疗效和安全性。方法将60例伴有躯体疼痛的抑郁症患者随机分为两组,各30例,均给予度洛西汀口服8周,研究组同时联用rTMS,对照组则予假性rTMS刺激4周,观察8周。于治疗前及治疗后第1,2,3,4,8周应用汉密尔顿抑郁量表（HAMD）、医学结局研究用疼痛量表（MOSPM）和治疗中出现的不良反应量表（TESS）评定两组的治疗效果和安全性。结果治疗结束后两组的MOSPM和HAMD评分均较治疗前显著下降（P〈0．05）;治疗第1,2,3,4周,研究组的MOSPM评分低于对照组,差异有统计学意义（P〈0．05）;治疗第2,3,4周,研究组的HAMD评分低于对照组而显效率高于对照组,差异有统计学意义（P〈0．05）;治疗第8周,两组患者的MOSPM和HAMD评分及显效率差异均无统计学意义（P〉0．05）,治疗期间无严重不良反应发生。结论rTMS能有效治疗伴躯体疼痛的抑郁症,迅速缓解疼痛改善抑郁症状,早期疗效优于单一度洛西汀治疗,且安全性高。     

重复经颅磁刺激对抑郁障碍患者睡眠质量改善的临床研究

研究背景 目前抑郁障碍患病率呈逐年升高之趋势,综合性医院就诊的抑郁障碍患者多以躯体化症状为主诉,尤以睡眠障碍最为常见,改善睡眠质量成为迫切的需要.本研究探讨重复经颅磁刺激(rTMS)对改善抑郁障碍患者睡眠质量的疗效.方法 以躯体化症状就诊的抑郁障碍患者随机分为单纯药物治疗组(药物治疗组)和rTMS联合药物治疗组(联合治疗组),分别采用汉密尔顿焦虑量表(HAMA)和抑郁量表(HAMD)评价两种治疗方法的疗效.结果 两种治疗方法在不同观察时间点,各项评分差异均有统计学意义(P=0.000),且治疗方法与观察时间点之间存在交互作用(均P=0.000).与药物治疗组相比,联合治疗组患者治疗1、2和4周时HAMA评分、HAMD总评分和躯体化症状评分降低(均P=0.000);治疗1周时睡眠障碍评分降低(P=0.001);治疗1和2周时抑郁症状评分降低(均P=0.000).与治疗前相比,药物治疗组患者各项评分除治疗后1周差异无统计学意义(P＞0.05)外,其余各观察时间点差异均有统计学意义(P=0.000);联合治疗组患者治疗后各项评分差异均有统计学意义(P=0.000).治疗后1、2和4周,两组治疗总有效率比较,联合治疗组[63.64％(14/22)、86.36％(19/22)、90.91％ (20/22)]高于药物治疗组[20％ (4/20)、55％ (11/20)、75％(15/20)],差异有统计学意义(均P=0.000).结论 重复经颅磁刺激联合药物治疗抑郁障碍患者起效早、效果好,尤其对睡眠质量的改善优于单纯药物治疗,可以提高抑郁障碍患者的治疗依从性.     

Multi-locus transcranial magnetic stimulation system for electronically targeted brain stimulation

BackgroundTranscranial magnetic stimulation (TMS) allows non-invasive stimulation of the cortex. In multi-locus TMS (mTMS), the stimulating electric field (E-field) is controlled electronically without coil movement by adjusting currents in the coils of a transducer.ObjectiveTo develop an mTMS system that allows adjusting the location and orientation of the E-field maximum within a cortical region.MethodsWe designed and manufactured a planar 5-coil mTMS transducer to allow controlling the maximum of the induced E-field within a cortical region approximately 30 mm in diameter. We developed electronics with a design consisting of independently controlled H-bridge circuits to drive up to six TMS coils. To control the hardware, we programmed software that runs on a field-programmable gate array and a computer. To induce the desired E-field in the cortex, we developed an optimization method to calculate the currents needed in the coils. We characterized the mTMS system and conducted a proof-of-concept motor-mapping experiment on a healthy volunteer. In the motor mapping, we kept the transducer placement fixed while electronically shifting the E-field maximum on the precentral gyrus and measuring electromyography from the contralateral hand.ResultsThe transducer consists of an oval coil, two figure-of-eight coils, and two four-leaf-clover coils stacked on top of each other. The technical characterization indicated that the mTMS system performs as designed. The measured motor evoked potential amplitudes varied consistently as a function of the location of the E-field maximum.ConclusionThe developed mTMS system enables electronically targeted brain stimulation within a cortical region.     

Treatment of depression with transcranial direct current stimulation (tDCS): A Review

Major Depression Disorder (MDD) is usually accompanied by alterations of cortical activity and excitability, especially in prefrontal areas. These are reflections of a dysfunction in a distributed cortico-subcortical, bihemispheric network. Therefore it is reasonable to hypothesize that altering this pathological state with techniques of brain stimulation may offer a therapeutic target. Besides repetitive transcranial magnetic stimulation, tonic stimulation with weak direct currents (tDCS) modulates cortical excitability for hours after the end of stimulation, thus, it is a promising non-invasive therapeutic option. Early studies from the 1960s suggested some efficacy of DC stimulation to reduce symptoms in depression, but mixed results and development of psychotropic drugs resulted in an early abandonment of this technique. In the last years tDCS protocols have been optimized. Application of the newly developed stimulation protocols in patients with major depression has shown promise in few pilot studies. Further studies are needed to identify the optimal parameters of stimulation and the clinical and patient characteristics that may condition response to tDCS.     

Callosal and corticospinal tract function in patients with hydrocephalus: a morphometric and transcranial magnetic stimulation study

In 15 patients with symptomatic hydrocephalus, pressure-induced morphological changes of the brain and the function of callosal and corticospinal fibres were studied. Morphometry of the corpus callosum (CC) was performed on midsagittal MR images. Focal transcranial magnetic stimulation of the motor cortex was used to assess simultaneously excitatory motor responses in contralateral hand muscle (corticospinally mediated effect) and inhibition of tonic EMG activity in ipsilateral hand muscles (transcallosal inhibition (TI) of the contralateral motor cortex). Before a shunt operation, the midsagittal area of the CC was reduced by 34% on average. The height and, to a lesser degree the length, of the CC were increased before the shunt operation. Thresholds and central motor latencies of corticospinally mediated responses were normal, response amplitudes were smaller than in normal subjects. Motor thresholds increased from 38, SD 5 to 52, SD 8% (P<0.01) within 7 days after ventricular drainage, reflecting the increase in the distance between stimulation coil and brain. The threshold increase paralleled a restoration of normal anatomical conditions within 7 days after shunt operation and the improvement of motor symptoms and might be a predictor of successful decompression. Transcallosal inhibition could be elicited in all patients. The measurements of TI lay within the normal range except the duration, which was prolonged in 73% of 15 patients before shunt operation as a probable indicator of an increased dispersion of callosal conduction. The normalization of the area and shape of the CC after shunt operation and the normal corticospinal and callosal conduction times exclude degeneration, demyelination or functional block of a large proportion of callosal or corticospinal tract fibres or a substantial loss of nerve cells in motor cortex. Received: 22 October 1997 Received in revised form: 13 January 1998 Accepted: 17 January 1998     

Efficacy of repetitive transcranial magnetic stimulation for Tourette syndrome: A systematic review and meta-analysis

Background

While previous studies have investigated the effect of repetitive transcranial magnetic stimulation (rTMS) in treating Tourette syndrome (TS), the results remain inconclusive.

Modification of cortical excitability induced by gabapentin: a study by transcranial magnetic stimulation

Transcranial magnetic stimulation (TMS) was employed before and after a single dose of gabapentin to evaluate how this drug affects the activity of excitatory and inhibitory circuits within the motor cortex. Eleven healthy volunteers were studied. For the evaluation of cortical excitability, the following parameters were taken into account: resting and active motor threshold (RMT, AMT); cortical silent period (CSP); and intracortical inhibition (ICI) and facilitation (ICF). Peripheral silent period (PSP) was also detected. All parameters were measured before and 3 and 24 hours after 800 mg gabapentin was administered in a single oral dose. Gabapentin deepened the ICI and suppressed the ICF at 3 h but not at 5 h after dosing. We conclude that, in the normal human brain, gabapentin may act on intracortical excitability by shifting the balance towards less excitation and more inhibition. Received: 30 March 2001 / Accepted in revised form: 17 May 2001     

Deconvolution of transcranial magnetic stimulation (TMS) maps

Summary. Transcranial magnetic stimulation (TMS) is a noninvasive method for local stimulation of cerebral cortex using a small coil's pulsed magnetic field. TMS response maps consist of measured responses to stimulations at points on a scalp-referenced grid and are used to study the topography of the brain's inhibitory and excitatory response. Because the magnetic field distributions of stimulation coils are 1–2 centimeters wide and 2–3 centimeters long, and the induced electric fields are even broader, the resolution of TMS maps is limited and the actual region of cortical stimulation is poorly defined. To better characterize the activation pattern, a practical mathematical procedure was developed for deconvolving a spherical model approximation of the coil's induced electric field distribution (here measured in a phantom) from the TMS response maps. This procedure offers an integrated, internally consistent method for processing TMS response maps to estimate the spatial distribution of motor cortex activations and inhibitions. Received February 7, 2000; accepted July 3, 2000     

诊断性经颅磁刺激研究进展

经颅磁刺激是一种无创性神经电生理学技术,经颅磁刺激运动诱发电位已广泛应用于运动皮质兴奋性与皮质延髓束、皮质脊髓束传导功能的评价。近年随着对磁刺激原理的深入了解和刺激线圈、刺激模式的不断多样化,经颅磁刺激在神经病学临床诊断中的应用不断拓展,逐渐形成更加科学和标准化的运动诱发电位操作流程。本文拟对诊断性经颅磁刺激常规刺激模式研究进展、特殊模式刺激方案,以及经颅磁刺激与脑电图、f MRI的联合应用进行综述。     

Cortical involvement in myopathies: Insights from transcranial magnetic stimulation

Objective

There is increasing evidence that an involvement of central nervous system (CNS) can occur in several myopathies. Transcranial magnetic stimulation (TMS) may represent a valuable tool for investigating important neurophysiological and pathophysiological aspects of cortical involvement in neuromuscular disorders. In this review paper we aimed to perform a systematic search of the studies employing TMS techniques in subjects suffering from myopathies.

经颅磁刺激技术在精神科的应用

在使用药物治疗精神科疾病的演化过程中,我们常常发现一些新兴药物看似有前途却很快地被淘汰,或是事实证明它们并没有如我们所想地那么有效,而更多时候,不论医生还是患者都希望药物的疗效不因为它的不良反应而大打折扣。20世纪三四十年代,曾掀起过针对精神科疾病运用躯体治疗方案的热潮,如胰岛素昏迷疗法、疟疾发热疗法和运用电流或是化学制剂诱发癫痫治疗情绪障碍均是在那个时代提出并在临床开始应用的。