Research hotspots and effectiveness of repetitive transcranial magnetic stimulation in stroke rehabilitation

Repetitive transcranial magnetic stimulation, as a relatively new type of rehabilitation treatment, is a painless and non-invasive method for altering brain excitability. Repetitive transcranial magnetic stimulation has been widely used in the neurorehabilitation of stroke patients. Here, we used CiteSpace software to visually analyze 315 studies concerning repetitive transcranial magnetic stimulation for stroke rehabilitation from 1999 to 2019, indexed by Web of Science, to clarify the research hotspots in different periods and characterize the gradual process of discovery in this field. We found that four main points were generally accepted:(1) repetitive transcranial magnetic stimulation has a positive effect on motor function recovery in patients with subcortical stroke;(2) it may be more advantageous for stroke patients to receive low-frequency repetitive transcranial magnetic stimulation in the unaffected hemispheres than to receive high-frequency repetitive transcranial magnetic stimulation in affected hemisphere;(3) low-frequency repetitive transcranial magnetic stimulation has become a potential therapeutic tool for patients with non-fluent aphasia after chronic stroke for neurological rehabilitation and language recovery; and(4) there are some limitations to these classic clinical studies, such as small sample size and low test efficiency. Our assessment indicates that prospective, multi-center, large-sample, randomized controlled clinical trials are still needed to further verify the effectiveness of various repetitive transcranial magnetic stimulation programs for the rehabilitation of stroke patients.     

Contribution of transcranial magnetic stimulation in restless legs syndrome: pathophysiological insights and therapeutical approaches

Transcranial magnetic stimulation (TMS) may offer a reliable means to characterize significant pathophysiologic and neurochemical aspects of restless legs syndrome (RLS). Namely, TMS has revealed specific patterns of changes in cortical excitability and plasticity, in particular dysfunctional inhibitory mechanisms and sensorimotor integration, which are thought to be part of the pathophysiological mechanisms of RLS rather than reflect a non-specific consequence of sleep architecture alteration.If delivered repetitively, TMS is able to transiently modulate the neural activity of the stimulated and connected areas. Some studies have begun to therapeutically use repetitive TMS (rTMS) to improve sensory and motor disturbances in RLS. High-frequency rTMS applied over the primary motor cortex or the supplementary motor cortex, as well as low-frequency rTMS over the primary somatosensory cortex, seem to have transient beneficial effects. However, further studies with larger patient samples, repeated sessions, an optimized rTMS setup, and clinical follow-up are needed in order to corroborate preliminary results.Thus, we performed a systematic search of all the studies that have used TMS and rTMS techniques in patients with RLS.     

组织多普勒成像评价左房收缩功能的临床研究

目的应用多普勒组织成像技术测定61名健康成人二尖瓣环运动峰值速率(Am),以评价Am在左房收缩功能中的价值。方法观察61名无心脏疾患者的Am,Am值为二尖瓣前、后、左、右侧心房收缩期二尖瓣环运动峰值速率的平均值;并与左房收缩时左房面积改变分数(FAC)和容积改变分数(FVC)作相关性研究。结果61例研究对象平均FAC和FVC分别为(31±10)%和(42±11)%;Am为(13.4±3.2)cm/s;直线回归分析显示,Am与FAC和FVC均呈正相关(r=0.78和0.82;P均<0.001)。结论Am与FAC、FVC具有良好相关性,从而为临床评价左房收缩功能提供了一种简便而快速的方法。     

Cerebral autoregulation is preserved in multiple system atrophy: A transcranial Doppler study.

Patients with multiple system atrophy (MSA) present large changes in blood pressure (BP) due to autonomic disturbances. We analyzed how this change may influence dynamic cerebral autoregulation (DCA). Simultaneous recordings of arterial BP (Finapres) and middle cerebral artery (MCA) blood flow velocity (BFV) (transcranial Doppler) were performed in 10 patients with MSA (61 +/- 12 yr of age) and 12 healthy volunteers (61 +/- 11 yr of age): cerebral BFV response to oscillations in mean BP was studied in the supine position by cross-spectral analysis of mean BP and mean MCA BFV. The DCA was also studied during the decrease in BP the first seconds when standing up from a sitting position by the assessment of the cerebrovascular resistance index (CR; mean BP/mean MCA BFV ratio). The MCA BFV/BP cross-spectral analysis showed a phase for the mid-frequency band (0.07-0.2 Hz) significantly larger in MSA, suggesting more active autoregulation in response to larger changes in BP. Changes in CR reflecting the rate of autoregulation, when standing did not differ between the two groups. These data suggest that dynamic cerebral autoregulation is preserved in MSA.     

Sources of Variability in the Detection of Cerebral Emboli with Transcranial Doppler During Cardiac Surgery

OBJECTIVE: The application of intensity thresholds for embolus detection with transcranial Doppler (TCD) can exclude from analysis an unrecognized proportion of high-intensity transient signals (HITS))whose intensities are below the threshold. The lack of consistent threshold criteria between clinical trials may explain part of the discrepancy in the reported HITS counts. We investigated the effect of choosing different thresholds on the sensitivity and specificity of detecting HITS during cardiopulmonary bypass (CPB). METHODS: Two observers independently analyzed TCD recordings from 8 patients under CPB. Doppler signals were classified as true HITS, equivocal HITS, artifacts, and Doppler speckles according to preestablished criteria. The relative intensity of Doppler signals was measured by two different methods (TCD software vs manual). Receiver Operating Characteristic curves determined the optimal threshold for each of the two intensity methods. RESULTS: Reviewers achieved agreement in 96% of 2190 Doppler signals (kappa = 0.90). Relative intensities calculated with the TCD-software method were 3 dB (95% CI: 3.0-3.4) higher than the manual method. The optimal threshold was found at 10 dB (sensitivity: 99%; specificity: 90.8%) with the software method and at 7 dB with the manual method (sensitivity: 96%; specificity: 83%). The use of an intensity threshold 2 dB higher than the optimal increased the rejection of true HITS by 8% and 14%, respectively. CONCLUSIONS: Using intensity thresholds higher than the optimal for embolus detection decreases HITS counts. Choosing a threshold depends on the type of method used for measuring the signal intensity. Uniform threshold criteria and comparative studies between different Doppler devices are necessary for making clinical trials more comparable.     

Role of intracortical mechanisms in the late part of the silent period to transcranial stimulation of the human motor cortex

Transcranial magnetic stimulation (TMS) and transcranial electrical stimulation (TES) of the human motor cortex produce a silent period (SP) following motor evoked potentials (MEPs). The early part of the SP can be explained by decreased alpha motor neuron excitability, whereas the late part is presumably due to suprasegmental mechanisms. In order to determine the level of the suprasegmental contribution to the generation of SPs, we recorded excitatory and inhibitory responses to TMS, TES, and percutaneous electrical brainstem stimulation (PBS) in the voluntarily activated first dorsal interosseous muscle of the hand. Stimulus intensities were set so that PBS and TES induced MEPs with areas equal to or larger than those of MEPs obtained with TMS. This procedure revealed that SPs were 49% and 83% shorter with TES and PBS, respectively, than with TMS. As TMS is more effective than TES or PBS in activating cortical interneurons, these findings support the idea that a significant component of the SP arises from intracortical mechanisms.     

脑梗死老年患者康复治疗前后的脑血流动力学

目的　观察脑梗死老年患者康复治疗期的脑血流动力学变化。　方法　应用经颅多普勒超声仪检测30例脑梗死康复期老年患者治疗前后以及 2 0例老年健康对照组的双侧大脑中动脉 (MCA)血流参数 :收缩期血流速度 (Vs)、舒张期血流速度 (Vd)、平均流速 (Vm)、阻力指数 (RI)、搏动指数 (PI)。　结果　 (1)与对照组比较 ,脑梗死组 MCA流速 Vs、Vd、Vm显著降低 ,RI、PI显著增高 (P<0 .0 1) ;(2 )体疗组经海水浴体疗运动 4疗程后 MCA流速 Vs、Vd、Vm明显增高 (P<0 .0 1) ,RI、PI显著降低 (P<0 .0 1) ,而休养组患者则改变不明显 (P>0 .0 5 )。　结论　脑梗死老年患者恢复期脑循环及血管贮备功能尚差 ,海水浴体疗运动一定疗程后可改善患者心脑血氧供应和脑血流动力学状况。