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1.
Peter Poortvliet Billie Hsieh Andrew Cresswell Jacky Au Marcus Meinzer 《Clinical neurophysiology》2018,129(1):33-41
Objective
Rehabilitation interventions contribute to recovery of impaired postural control, but it remains a priority to optimize their effectiveness. A promising strategy may involve transcranial direct current stimulation (tDCS) of brain areas involved in fine-tuning of motor adaptation. This study explored the effects of cerebellar tDCS (ctDCS) on postural recovery from disturbance by Achilles tendon vibration.Methods
Twenty-eight healthy volunteers participated in this sham-ctDCS controlled study. Standing blindfolded on a force platform, four trials were completed: 60?s quiet standing followed by 20?min active (anodal-tDCS, 1?mA, 20?min, N?=?14) or sham-ctDCS (40?s, N?=?14) tDCS; three quiet standing trials with 15?s of Achilles tendon vibration and 25?s of postural recovery. Postural steadiness was quantified as displacement, standard deviation and path derived from the center of pressure (COP).Results
Baseline demographics and quiet standing postural steadiness, and backwards displacement during vibration were comparable between groups. However, active-tDCS significantly improved postural steadiness during vibration and reduced forward displacement and variability in COP derivatives during recovery.Conclusions
We demonstrate that ctDCS results in short-term improvement of postural adaptation in healthy individuals.Significance
Future studies need to investigate if multisession ctDCS combined with training or rehabilitation interventions can induce prolonged improvement of postural balance. 相似文献2.
Pedro Caldana Gordon Christoph Zrenner Debora Desideri Paolo Belardinelli Brigitte Zrenner André Russowsky Brunoni Ulf Ziemann 《Brain stimulation》2018,11(5):1024-1032
Background
Transcranial direct current stimulation (tDCS) is a non-invasive brain stimulation technique with potential for cost-effective therapeutic neuromodulation. Although positive therapeutic effects were found by stimulating the dorsolateral prefrontal cortex (DLPFC), few studies have investigated physiological effects of DLPFC-tDCS.Objectives
To investigate effects of tDCS with different parameter settings applied to the left DLPFC on cortical responses, measured by resting-state electroencephalography (rs-EEG) and transcranial magnetic stimulation (TMS)-evoked/induced EEG responses.Methods
22 healthy subjects underwent 5 tDCS sessions with different tDCS parameter settings in a double-blinded randomized crossover design (1: 1.5?mA, anode left-DLPFC, cathode right-DLPFC; 2: 1.5?mA, cathode left-DLPFC, anode right-DLPFC; 3: 0.5?mA, anode left-DLPFC, cathode right-DLPFC; 4: 1.5?mA, anode left-DLPFC, cathode left deltoid muscle; 5: sham stimulation). Rs-EEG and TMS-EEG were recorded before and after tDCS.Results
Rs-EEG power spectrum analysis showed no difference comparing baseline with post stimulation in any of the tDCS conditions. TMS-EEG evoked potential amplitude decreased in parietal cortex after 1.5?mA left-DLPFC anodal tDCS, and TMS-induced gamma and theta oscillations decreased after all conditions using left-DLPFC anodal tDCS. Left-DLPFC cathodal tDCS did not lead to significant change. None of the post-intervention changes was different when comparing the effects across conditions, including sham.Conclusions
Our study does not provide evidence that a single tDCS session results in significant changes in rs-EEG, using the current stimulation parameters. Significant changes in EEG responses to TMS pulses were observed following the anodal 1.5?mA tDCS interventions, although these changes were not statistically significant in a group comparison. 相似文献3.
Shinichi Iwasaki Chisato Fujimoto Naoya Egami Makoto Kinoshita Fumiharu Togo Yoshiharu Yamamoto Tatsuya Yamasoba 《Brain stimulation》2018,11(4):709-715
Background
Galvanic vestibular stimulation delivered as zero-mean current noise (noisy GVS) has been shown to improve static and dynamic postural stability probably by enhancing vestibular information.Objective
/Hypothesis: To examine the effect of an imperceptible level of noisy GVS on dynamic locomotion in normal subjects as well as in patients with bilateral vestibulopathy.Methods
Walking performance of 19 healthy subjects and 12 patients with bilateral vestibulopathy at their preferred speed was examined during application of noisy GVS with an amplitude ranging from 0 to 1000?μA. The gait velocity, stride length and stride time were analyzed.Results
Noisy GVS had significant effects on gait velocity, stride length and stride time in healthy subjects as well as in patients with bilateral vestibulopathy (p?<?0.05). The optimal amplitude of noisy GVS improved gait velocity by 10.9?±?1.2%, stride length by 5.7?±?1.2% and stride time by 4.6?±?7% (p?<?0.0001) compared to the control session in healthy subjects. The optimal stimulus improved gait velocity by 12.8?±?1.3%, stride length by 8.3?±?1.1% and stride time by 3.7?±?7% (p?<?0.0001) in patients with bilateral vestibulopathy. The improved values of these parameters of locomotion by noisy GVS in the patients were not significantly different from those in healthy subjects in the control condition (p?>?0.4).Conclusion
Noisy GVS is effective in improving gait performance in healthy subjects as well as in patients with bilateral vestibulopathy. 相似文献4.
Bashar W. Badran Logan T. Dowdle Oliver J. Mithoefer Nicholas T. LaBate James Coatsworth Joshua C. Brown William H. DeVries Christopher W. Austelle Lisa M. McTeague Mark S. George 《Brain stimulation》2018,11(3):492-500
Background
Electrical stimulation of the auricular branch of the vagus nerve (ABVN) via transcutaneous auricular vagus nerve stimulation (taVNS) may influence afferent vagal networks. There have been 5 prior taVNS/fMRI studies, with inconsistent findings due to variability in stimulation targets and parameters.Objective
We developed a taVNS/fMRI system to enable concurrent electrical stimulation and fMRI acquisition to compare the effects of taVNS in relation to control stimulation.Methods
We enrolled 17 healthy adults in this single-blind, crossover taVNS/fMRI trial. Based on parameters shown to affect heart rate in healthy volunteers, participants received either left tragus (active) or earlobe (control) stimulation at 500?μs 25?HZ for 60?s (repeated 3 times over 6?min). Whole brain fMRI analysis was performed exploring the effect of: active stimulation, control stimulation, and the comparison. Region of interest analysis of the midbrain and brainstem was also conducted.Results
Active stimulation produced significant increased BOLD signal in the contralateral postcentral gyrus, bilateral insula, frontal cortex, right operculum, and left cerebellum. Control stimulation produced BOLD signal activation in the contralateral postcentral gyrus. In the active vs. control contrast, tragus stimulation produced significantly greater BOLD increases in the right caudate, bilateral anterior cingulate, cerebellum, left prefrontal cortex, and mid-cingulate.Conclusion
Stimulation of the tragus activates the cerebral afferents of the vagal pathway and combined with our review of the literature suggest that taVNS is a promising form of VNS. Future taVNS/fMRI studies should systematically explore various parameters and alternative stimulation targets aimed to optimize this novel form of neuromodulation. 相似文献5.
Carina França Daniel Ciampi de Andrade Manoel Jacobsen Teixeira Ricardo Galhardoni Valquiria Silva Egberto Reis Barbosa Rubens Gisbert Cury 《Brain stimulation》2018,11(2):249-260
Background
The cerebellum is involved in the pathophysiology of many movement disorders and its importance in the field of neuromodulation is growing.Objectives
To review the current evidence for cerebellar modulation in movement disorders and its safety profile.Methods
Eligible studies were identified after a systematic literature review of the effects of cerebellar modulation in cerebellar ataxia, Parkinson's disease (PD), essential tremor (ET), dystonia and progressive supranuclear palsy (PSP). Neuromodulation techniques included transcranial magnetic stimulation (TMS), transcranial direct current stimulation (tDCS) and deep brain stimulation (DBS). The changes in motor scores and the incidence of adverse events after the stimulation were reviewed.Results
Thirty-four studies were included in the systematic review, comprising 431 patients. The evaluation after stimulation ranged from immediately after to 12 months after. Neuromodulation techniques improved cerebellar ataxia due to vascular or degenerative etiologies (TMS, tDCS and DBS), dyskinesias in PD patients (TMS), gross upper limb movement in PD patients (tDCS), tremor in ET (TMS and tDCS), cervical dystonia (TMS and tDCS) and dysarthria in PSP patients (TMS). All the neuromodulation techniques were safe, since only three studies reported the existence of side effects (slight headache after TMS, local skin erythema after tDCS and infectious complication after DBS). Eleven studies did not mention if adverse events occurred.Conclusions
Cerebellar modulation can improve specific symptoms in some movement disorders and is a safe and well-tolerated procedure. Further studies are needed to lay the groundwork for new researches in this promising target. 相似文献6.
Background
Alpha (8–14?Hz) oscillatory power is linked to cortical excitability and corresponding modulations of sensory evoked potentials and perceptual detection performance. In somatosensory cortex (S1), negative linear and inverted U-shape relationships exist, whereas its effect on the primary motor cortex (M1) is hardly known.Objective
We used real-time EEG-triggered transcranial magnetic stimulation (TMS) of M1 to characterize the relationship between spontaneous sensorimotor mu-alpha power fluctuations at rest and corticospinal excitability.Methods
In 16 subjects, mu-alpha power was continuously monitored over the left sensorimotor cortex, and each 10%-percentile bin of the individual mu-alpha power distribution was repeatedly targeted in pseudorandomized order by single-pulse TMS of left M1, measuring motor evoked potentials (MEP) in the contralateral hand.Results
We found a weak positive relationship between mu-alpha power and MEP amplitude.Conclusion
Sensorimotor mu-alpha power may reflect a net facilitation or disinhibition of M1, possibly resulting from mu-alpha based suppression of excitatory and inhibitory input from S1. 相似文献7.
Pratik Y. Chhatbar Steven A. Kautz Istvan Takacs Nathan C. Rowland Gonzalo J. Revuelta Mark S. George Marom Bikson Wuwei Feng 《Brain stimulation》2018,11(4):727-733
Background
Transcranial direct current stimulation (tDCS) is a promising brain modulation technique for several disease conditions. With this technique, some portion of the current penetrates through the scalp to the cortex and modulates cortical excitability, but a recent human cadaver study questions the amount. This insufficient intracerebral penetration of currents may partially explain the inconsistent and mixed results in tDCS studies to date. Experimental validation of a transcranial alternating current stimulation-generated electric field (EF) in vivo has been performed on the cortical (using electrocorticography, ECoG, electrodes), subcortical (using stereo electroencephalography, SEEG, electrodes) and deeper thalamic/subthalamic levels (using DBS electrodes). However, tDCS-generated EF measurements have never been attempted.Objective
We aimed to demonstrate that tDCS generates biologically relevant EF as deep as the subthalamic level in vivo.Methods
Patients with movement disorders who have implanted deep brain stimulation (DBS) electrodes serve as a natural experimental model for thalamic/subthalamic recordings of tDCS-generated EF. We measured voltage changes from DBS electrodes and body resistance from tDCS electrodes in three subjects while applying direct current to the scalp at 2?mA and 4?mA over two tDCS montages.Results
Voltage changes at the level of deep nuclei changed proportionally with the level of applied current and varied with different tDCS montages.Conclusions
Our findings suggest that scalp-applied tDCS generates biologically relevant EF. Incorporation of these experimental results may improve finite element analysis (FEA)-based models. 相似文献8.
Donel M. Martin Shawn M. McClintock Scott T. Aaronson Angelo Alonzo Mustafa M. Husain Sarah H. Lisanby William M. McDonald Adith Mohan Stevan Nikolin John O&#x;Reardon Cynthia Shannon Weickert Colleen K. Loo 《Brain stimulation》2018,11(6):1282-1290
Background
Transcranial direct current stimulation (tDCS) has promising antidepressant effects, however, clinical trials have shown variable efficacy. Pre-treatment neurocognitive functioning has previously been identified as an inter-individual predictor of tDCS antidepressant efficacy.Objective
In this international multicentre, sham-controlled study, we investigated this relationship while also assessing the influence of clinical and genotype (BDNF Val66Met and COMT Val158Met polymorphisms) factors as predictors of response to active tDCS.Methods
The study was a triple-masked, parallel, randomized, controlled design across 6 international academic medical centers. Participants were randomized to active (2.5?mA) or sham (34?μA) tDCS for 30?min each session for 20 sessions. The anode was centered over the left dorsolateral prefrontal cortex at F3 (10/20 EEG system) and the cathode over the lateral right frontal area at F8.Results
Better pre-treatment attentional processing speed on the Ruff 2 & 7 Selective Attention Test (Total Speed: β?=?0.25, p?<?.05) and concurrent antidepressant medication use (β?=?0.31, p?<?.05) predicted antidepressant efficacy with active tDCS. Genotype differences in the BDNF Val66Metand COMT Val158Met polymorphisms were not associated with antidepressant effects. Secondary analyses revealed that only participants in the highest performing Ruff 2 & 7 Total Speed group at pre-treatment in both active and sham tDCS conditions showed significantly greater antidepressant response compared to those with lower performance at both the 2 and 4 week treatment time points (p?<?.05).Conclusions
These results suggest that high pre-treatment attentional processing speed may be relevant for identifying participants more likely to show better tDCS antidepressant response to both high (2.5?mA) and very low (34?μA) current intensity stimulation.9.
Géraldine Martens Nicolas Lejeune Anthony Terrence O&#x;Brien Felipe Fregni Charlotte Martial Sarah Wannez Steven Laureys Aurore Thibaut 《Brain stimulation》2018,11(5):982-990
Background
Patients with chronic disorders of consciousness face a significant lack of treatment options.Objective
We aimed at investigating the feasibility and the behavioral effects of home-based transcranial direct current stimulation (tDCS), applied by relatives or caregivers, in chronic patients in minimally conscious state (MCS).Methods
Each participant received, in a randomized order, 20 sessions of active and 20 sessions of sham tDCS applied over the prefrontal cortex for 4 weeks; separated by 8 weeks of washout. Level of consciousness was assessed using the Coma Recovery Scale-Revised before the first stimulation (baseline), at the end of the 20 tDCS sessions (direct effects) and 8 weeks after the end of each stimulation period (long-term effects). Reported adverse events and data relative to the adherence (i.e., amount of sessions effectively received) were collected as well.Results
Twenty-seven patients completed the study and 22 patients received at least 80% of the stimulation sessions. All patients tolerated tDCS well, no severe adverse events were noticed after real stimulation and the overall adherence (i.e., total duration of stimulation) was good. A moderate effect size (0.47 and 0.53, for modified intention to treat and per protocol analysis, respectively) was observed at the end of the 4 weeks of tDCS in favor of the active treatment.Conclusions
We demonstrated that home-based tDCS can be used adequately outside a research facility or hospital by patients' relatives or caregivers. In addition, 4 weeks of tDCS moderately improved the recovery of signs of consciousness in chronic MCS patients. 相似文献10.
Vishal Rawji Matteo Ciocca André Zacharia David Soares Dennis Truong Marom Bikson John Rothwell Sven Bestmann 《Brain stimulation》2018,11(2):289-298
Background
Measurements and models of current flow in the brain during transcranial Direct Current Stimulation (tDCS) indicate stimulation of regions in-between electrodes. Moreover, the folded cortex results in local fluctuations in current flow intensity and direction, and animal studies suggest current flow direction relative to cortical columns determines response to tDCS.Methods
Here we test this idea by using Transcranial Magnetic Stimulation Motor Evoked Potentials (TMS-MEP) to measure changes in corticospinal excitability following tDCS applied with electrodes aligned orthogonal (across) or parallel to M1 in the central sulcus.Results
Current flow models predicted that the orthogonal electrode montage produces consistently oriented current across the hand region of M1 that flows along cortical columns, while the parallel electrode montage produces non-uniform current directions across the M1 cortical surface. We find that orthogonal, but not parallel, orientated tDCS modulates TMS-MEPs. We also show modulation is sensitive to the orientation of the TMS coil (PA or AP), which is thought to select different afferent pathways to M1.Conclusions
Our results are consistent with tDCS producing directionally specific neuromodulation in brain regions in-between electrodes, but shows nuanced changes in excitability that are presumably current direction relative to column and axon pathway specific. We suggest that the direction of current flow through cortical target regions should be considered for targeting and dose-control of tDCS. 相似文献11.
Yasuto Inukai Naofumi Otsuru Mitsuhiro Masaki Kei Saito Shota Miyaguchi Sho Kojima Hideaki Onishi 《Brain stimulation》2018,11(1):85-93
Background
The vestibular system is involved in the control of standing balance. Galvanic vestibular stimulation (GVS) is a noninvasive technique that can stimulate the vestibular system. In recent years, noisy GVS (nGVS) using noise current stimulation has been attempted, but it has not been clarified whether it affects postural sway in open-eye standing.Objective
The purpose of this study was to clarify the influence of nGVS on the center of pressure (COP) sway measurement in open-eye standing postural control and identify the responders of nGVS.Methods
nGVS (0.1–640 Hz) was delivered at 0.4 and 1.0 mA over the bipolar mastoid. COP sway root mean square area, sway path length, medio-lateral (ML) mean velocity, and antero-posterior (AP) mean velocity before and during nGVS in an open-eye standing posture was measured.Results
nGVS at 0.4 and 1.0 mA significantly reduced sway path length, mean velocity. The stimulation effect of nGVS was also large in subjects with a long sway path. For subjects with high COP sway of Baseline, nGVS was effective even with stimulation for a short duration (5 s).Conclusions
These findings suggest that nGVS improves postural sway in an open-eye standing posture among young subjects. 相似文献12.
Yiheng Tu Jiliang Fang Jin Cao Zengjian Wang Joel Park Kristen Jorgenson Courtney Lang Jun Liu Guolei Zhang Yanping Zhao Bing Zhu Peijing Rong Jian Kong 《Brain stimulation》2018,11(3):501-508
Background
Major depression is the fourth leading cause of disability worldwide and poses a socioeconomic burden worldwide. Transcutaneous vagus nerve stimulation (tVNS) is a promising noninvasive clinical device that may reduce the severity of major depression. However, the neural mechanism underlying continuous tVNS has not yet been elucidated.Objective
We aimed to explore the effect of hypothalamic subregion functional connectivity (FC) changes during continuous tVNS treatment on major depressive disorder (MDD) patients and to identify the potential biomarkers for treatment outcomes.Methods
Forty-one mild to moderate MDD patients were recruited and received either real or sham tVNS treatment for 4 weeks. We used a seed-to-whole brain approach to estimate the FC changes of hypothalamic subregions and their surrounding control areas during continuous tVNS treatment and explored their association with clinical outcome changes after 4 weeks of treatment.Results
Of the thirty-six patients that completed the study, those in the tVNS group had significantly lower scores on the 24-item Hamilton Depression (HAM-D) Rating Scale compared to the sham tVNS group after 4 weeks of treatment. The FC between the bilateral medial hypothalamus (MH) and rostral anterior cingulate cortex (rACC) was significantly decreased during tVNS but not during sham tVNS. The strength of this FC was significantly correlated with HAM-D improvements after 4 weeks of tVNS.Conclusion
The FC between the bilateral MH and rACC may serve as a potential biomarker for the tVNS state and predict treatment responses. Our results provide insights into the neural modulation mechanisms of continuous tVNS and reveal a potential therapeutic target for MDD patients. 相似文献13.
Casey S. Gilmore Patricia J. Dickmann Brent G. Nelson Greg J. Lamberty Kelvin O. Lim 《Brain stimulation》2018,11(2):302-309
Background
Impulsivity is a multidimensional personality trait observed across a variety of psychiatric disorders. Transcranial direct current stimulation (tDCS) applied over dorsolateral prefrontal cortex (DLPFC) has shown promise as an intervention to reduce impulsivity.Objective
To investigate the effects of tDCS paired with a decision-making task on risk-taking in Veterans with a clinical history of impulsive behavior.Methods
This was a randomized, single-blind, sham-controlled study. Participants performed the Balloon Analogue Risk Task (BART) while concurrently receiving either active or sham tDCS (right anodal/left cathodal over DLPFC) twice a day for five days. To evaluate generalization, the Risk Task was performed before and after the complete course of intervention. To evaluate durability, the BART and Risk Task were administered again at one and two month follow-up sessions.Results
Thirty Veterans participated: 15 received active tDCS and 15 received sham tDCS. For the trained BART task, individual growth curve analysis (IGC) examining individual variation of the growth rates over time showed no significant variations in individual trajectory changes over time (β = 0.02, p > 0.05). For the untrained Risk Task, IGC showed that the active tDCS group had a significant 46% decrease in risky choice from pre-to post-intervention, which persisted through the one and two month follow-up sessions. The sham tDCS group showed no significant change in risky choice from pre-to post-intervention.Conclusions
tDCS over DLPFC paired with a decision-making task effectively reduced risk-taking behavior in a group of Veterans with clinically-relevant impulsivity. Results suggest that this approach may be an effective neuroplasticity-based intervention for patients affected by impulsivity. 相似文献14.
Background
Theories of executive control propose that communication between medial frontal cortex (MFC) and lateral prefrontal cortex (lPFC) is critical for learning. 6-Hz phase synchronization may be the mechanism by which neural activity between MFC and lPFC is coordinated into a functional network. Recent evidence suggests that switching from eyes closed to open may induce a change in brain-state reflected by enhanced executive control and related functional connectivity.Objective/Hypothesis
To examine whether causal manipulation of MFC and lPFC can improve learning according to the brain-state induced by switching from eyes closed to open.Methods
Within-subjects, sham-controlled, double-blind study of 30 healthy subjects, each receiving 6-Hz in-phase high definition transcranial alternating-current stimulation (HD-tACS) applied to MFC and right lPFC prior to performing a time estimation task.Results
HD-tACS with eyes open improved learning ability relative to sham, whereas HD-tACS with eyes closed had no significant effect on behavior.Conclusion
Results suggest a phase-sensitive mechanism in frontal cortex mediates components of learning performance in a state-dependent manner. 相似文献15.
Zeinab Esmaeilpour Paola Marangolo Benjamin M. Hampstead Sven Bestmann Elisabeth Galletta Helena Knotkova Marom Bikson 《Brain stimulation》2018,11(2):310-321
Background
Transcranial direct current stimulation (tDCS) is investigated to modulate neuronal function by applying a fixed low-intensity direct current to scalp.Objectives
We critically discuss evidence for a monotonic response in effect size with increasing current intensity, with a specific focus on a question if increasing applied current enhance the efficacy of tDCS.Methods
We analyzed tDCS intensity does-response from different perspectives including biophysical modeling, animal modeling, human neurophysiology, neuroimaging and behavioral/clinical measures. Further, we discuss approaches to design dose-response trials.Results
Physical models predict electric field in the brain increases with applied tDCS intensity. Data from animal studies are lacking since a range of relevant low-intensities is rarely tested. Results from imaging studies are ambiguous while human neurophysiology, including using transcranial magnetic stimulation (TMS) as a probe, suggests a complex state-dependent non-monotonic dose response. The diffusivity of brain current flow produced by conventional tDCS montages complicates this analysis, with relatively few studies on focal High Definition (HD)-tDCS. In behavioral and clinical trials, only a limited range of intensities (1-2?mA), and typically just one intensity, are conventionally tested; moreover, outcomes are subject brain-state dependent. Measurements and models of current flow show that for the same applied current, substantial differences in brain current occur across individuals. Trials are thus subject to inter-individual differences that complicate consideration of population-level dose response.Conclusion
The presence or absence of simple dose response does not impact how efficacious a given tDCS dose is for a given indication. Understanding dose-response in human applications of tDCS is needed for protocol optimization including individualized dose to reduce outcome variability, which requires intelligent design of dose-response studies. 相似文献16.
William F. Stubbeman Bijan Zarrabi Silvia Bastea Victoria Ragland Raya Khairkhah 《Brain stimulation》2018,11(4):953-955
Background
Current medication and transcranial magnetic stimulation (TMS) treatments for depression bring only approximately one-third of patients to remission. Newer TMS techniques such as bilateral treatment, neuronavigation, and theta burst stimulation (TBS) show promise in improving remission rates. However, it is unclear whether newer off-label techniques improve outcomes enough to justify widespread implementation.Methods
An IRB approved retrospective chart review examined 58 primarily treatment-resistant (79%) depressed patients who received bilateral neuronavigated TBS-20Hz in a private outpatient clinic.Results
72% (42/58) of patients remitted (Beck Depression Inventory-II (BDI-II)?<?13) with an 81% decrease in BDI-II scores. 83% (48/58) of patients responded (BDI-II?≤?50%). Average time to remission was 7.3 treatment weeks (SD?=?4.5, Range 0.6–21.2). Overall, 40% (17/42) of remitters also successfully discontinued one or more pretreatment medications.Conclusions
Bilateral Neuronavigated TBS-20Hz TMS brought more than two-thirds of treatment refractory depressed patients to remission. TBS-20Hz may be critical for obtaining higher remission rates. Controlled trials are warranted. 相似文献17.
Background
There has been increased interest in the potential use of transcranial direct current stimulation (tDCS) as treatment for multiple conditions including depression, pain, and cognitive impairment. However, few studies account for the possible influence of comorbid medications when conducting tDCS research.Objective/Hypothesis
This literature review was conducted to examine what is currently known about the impact of medications on tDCS, provide recommendations for future research practices, and highlight areas where more research is needed.Methods
Key terms were searched in PubMed and Web of Science to identify studies that examine the impact of medication on tDCS effects in adults. Relevant papers' reference lists were also reviewed for thoroughness. Studies examined the effects of medication on 1 mA tDCS delivered to M1 (motor) and orbit/supraorbital (SO) area. All studies measured the effects of tDCS via MEP TMS paradigm.Results
Results of the literature review suggest multiple classes of medications, including sodium and calcium channel blockers, and medications that influence various neurotransmitter systems (GABA, dopamine, serotonin, etc.) may all impact tDCS effects on tissue excitability.Conclusions
Research to date suggests multiple classes of medications may impact tDCS effects. These results highlight the importance of documenting medication use in research subjects and carefully considering what types of medications should be allowed into tDCS trials. Many questions still remain regarding the exact mechanisms of action for tDCS and how various parameters (medication dosages, tDCS stimulation intensity, etc.) may further impact the effects of medications on tDCS. 相似文献18.
Martin Sommer Matteo Ciocca Raffaella Chieffo Paul Hammond Andreas Neef Walter Paulus John C. Rothwell Ricci Hannah 《Brain stimulation》2018,11(3):558-565
Background
Biphasic pulses produced by most commercially available TMS machines have a cosine waveform, which makes it difficult to study the interaction between the two phases of stimulation.Objective
We used a controllable pulse TMS (cTMS) device delivering quasi-rectangular pulse outputs to investigate whether monophasic are more effective than biphasic pulses.Methods
Temporally symmetric (“biphasic”) or highly asymmetric (“monophasic”) charge-balanced biphasic stimuli were used to target the hand area of motor cortex in the anterior-posterior (AP) or posterior-anterior (PA) initial current direction.Results
We observed the lowest motor thresholds and shortest motor evoked potential (MEP) latencies with initial PA pulses, and highest thresholds and longest latencies with AP pulses. Increasing pulse symmetry tended to increase threshold with a PA direction whereas it lowered thresholds and shortened latencies with an AP direction. Furthermore, it steepened the MEP input-output curve with both directions.Conclusions
“Biphasic” TMS pulses can be viewed as two monophasic pulses of opposite directions, each stimulating a different set of interneurons with different thresholds (PA?<?AP). At threshold, the reverse phase of an initially PA pulse increases threshold compared with “monophasic” stimulation. At higher intensities, the reverse phase begins to activate AP-sensitive neurones and increase the effectiveness of stimulation above that of a “monophasic” PA pulse. “Biphasic” stimulation with initially AP pulses is dominated at threshold by activation produced by the lower threshold reverse (PA) phase.Significance
The effects of biphasic stimulation are best understood as the summed output of two independent sets of directionally selective neural populations. 相似文献19.
Daniel G. da S. Machado Gozde Unal Suellen M. Andrade Alexandre Moreira Leandro R. Altimari André R. Brunoni Stéphane Perrey Alexis R. Mauger Marom Bikson Alexandre H. Okano 《Brain stimulation》2019,12(3):593-605
Background
Transcranial direct current stimulation (tDCS) has been used to improve exercise performance, though the protocols used, and results found are mixed.Objective
We aimed to analyze the effect of tDCS on improving exercise performance.Methods
A systematic search was performed on the following databases, until December 2017: PubMed/MEDLINE, Embase, Web of Science, SCOPUS, and SportDiscus. Full-text articles that used tDCS for exercise performance improvement in adults were included. We compared the effect of anodal (anode near nominal target) and cathodal (cathode near nominal target) tDCS to a sham/control condition on the outcome measure (performance in isometric, isokinetic or dynamic strength exercise and whole-body exercise).Results
22 studies (393 participants) were included in the qualitative synthesis and 11 studies (236 participants) in the meta-analysis. The primary motor cortex (M1) was the main nominal tDCS target (n?=?16; 72.5%). A significant effect favoring anodal tDCS (a-tDCS) applied before exercise over M1 was found on cycling time to exhaustion (mean difference?=?93.41?s; 95%CI?=?27.39?s–159.43?s) but this result was strongly influenced by one study (weight?=?84%), no effect was found for cathodal tDCS (c-tDCS). No significant effect was found for a-tDCS applied on M1 before or during exercise on isometric muscle strength of the upper or lower limbs. Studies regarding a-tDCS over M1 on isokinetic muscle strength presented mixed results. Individual results of studies using a-tDCS applied over the prefrontal and motor cortices either before or during dynamic muscle strength testing showed positive results, but performing meta-analysis was not possible.Conclusion
For the protocols tested, a-tDCS but not c-tDCS vs. sham over M1 improved exercise performance in cycling only. However, this result was driven by a single study, which when removed was no longer significant. Further well-controlled studies with larger sample sizes and broader exploration of the tDCS montages and doses are warranted. 相似文献20.
E.P. Buell K.W. Loerwald C.T. Engineer M.S. Borland J.M. Buell C.A. Kelly I.I. Khan S.A. Hays M.P. Kilgard 《Brain stimulation》2018,11(6):1218-1224