Anodal Transcranial Direct Current Stimulation of the Motor Cortex Ameliorates Chronic Pain and Reduces Short Intracortical Inhibition

ContextConsecutive sessions of transcranial direct current stimulation (tDCS) over the primary motor cortex (M1) may be a suitable therapy to treat chronic pain, as it can modulate neural activities in the stimulated and interconnected regions.ObjectivesThe present study investigated the analgesic effect of five consecutive days of anodal/sham tDCS using subjective (visual analog scale [VAS]) and objective (cortical excitability measured by transcranial magnetic stimulation [TMS]) measurements.MethodsPatients with therapy-resistant chronic pain syndromes (trigeminal neuralgia, poststroke pain syndrome, back pain, fibromyalgia) participated. As this clinical trial was an exploratory study, statistical analyses implemented exploratory methods. Twelve patients, who underwent both anodal and sham tDCS, were analyzed using a crossover design. An additional nine patients had only anodal or sham stimulation. tDCS was applied over the hand area of the M1 for 20 minutes, at 1 mA for five consecutive days, using a randomized, double-blind design. Pain was assessed daily using a VAS rating for one month before, during, and one month post-stimulation. M1 excitability was determined using paired-pulse TMS.ResultsAnodal tDCS led to a greater improvement in VAS ratings than sham tDCS, evident even three to four weeks post-treatment. Decreased intracortical inhibition was demonstrated after anodal stimulation, indicating changes in cortico-cortical excitability. No patient experienced severe adverse effects; seven patients suffered from light headache after anodal and six after sham stimulation.ConclusionResults confirm that five daily sessions of tDCS over the hand area of the M1 can produce long-lasting pain relief in patients with chronic pain.     

Stimulations cérébrales non invasives : une nouvelle option thérapeutique pour la douleur chronique ?

Chronic pain care with pharmacological treatment is limited due to efficacy and tolerance. Epidural motor cortex stimulation (MCS) has proven to be effective for pain relief in chronic pain. The aim of these noninvasive stimulation techniques is to obtain the same efficacy while avoiding surgery. Repetitive transcranial magnetic stimulation (rTMS) has an action mode similar to MCS. Targeting the primary motor cortex, it is possible to obtain an analgesic effect that can last for > 2 weeks after each session. Concerning transcranial electrical stimulation, it can rely on direct current (tDCS for transcranial Direct Current Stimulation) or alternating current (tACS for transcranial Alternating Current Stimulation and tRNS for transcranial Random Noise Stimulation). This electrical stimulation leads to a modification of the membrane potential from a large brain zone. The aim of this brief article is to give several recent information concerning the mode of action and the efficacy of these two techniques.     

Efficacy of Transcranial Direct Current Stimulation and Repetitive Transcranial Magnetic Stimulation for Treating Fibromyalgia Syndrome: A Systematic Review

Objective: To systematically review the literature to date applying repetitive transcranial magnetic stimulation (rTMS) or transcranial direct current stimulation (tDCS) for patients with fibromyalgia syndrome (FMS). Method: Electronic bibliography databases screened included PubMed, Ovid MEDLINE, PsychINFO, CINAHL, and Cochrane Library. The keyword “fibromyalgia” was combined with (“transcranial” and “stimulation”) or “TMS” or “tDCS” or “transcranial magnetic stimulation” or “transcranial direct current stimulation”. Results: Nine of 23 studies were included; brain stimulation sites comprised either the primary motor cortex (M1) or the dorsolateral prefrontal cortex (DLPFC). Five studies used rTMS (high‐frequency‐M1: 2, low‐frequency‐DLPFC: 2, high‐frequency‐DLPFC: 1), while 4 applied tDCS (anodal‐M1: 1, anodal‐M1/DLPFC: 3). Eight were double‐blinded, randomized controlled trials. Most (80%) rTMS studies that measured pain reported significant decreases, while all (100%) tDCS studies with pain measures reported significant decreases. Greater longevity of significant pain reductions was observed for excitatory M1 rTMS/tDCS. Conclusion: Studies involving excitatory rTMS/tDCS at M1 showed analogous pain reductions as well as considerably fewer side effects compared to FDA apaproved FMS pharmaceuticals. The most commonly reported side effects were mild, including transient headaches and scalp discomforts at the stimulation site. Yearly use of rTMS/tDCS regimens appears costly ($11,740 to 14,507/year); however, analyses to apapropriately weigh these costs against clinical and quality of life benefits for patients with FMS are lacking. Consequently, rTMS/tDCS should be considered when treating patients with FMS, particularly those who are unable to find adequate symptom relief with other therapies. Further work into optimal stimulation parameters and standardized outcome measures is needed to clarify associated efficacy and effectiveness.     

A sham-controlled, phase II trial of transcranial direct current stimulation for the treatment of central pain in traumatic spinal cord injury

Past evidence has shown that motor cortical stimulation with invasive and non-invasive brain stimulation is effective to relieve central pain. Here we aimed to study the effects of another, very safe technique of non-invasive brain stimulation--transcranial direct current stimulation (tDCS)--on pain control in patients with central pain due to traumatic spinal cord injury. Patients were randomized to receive sham or active motor tDCS (2mA, 20 min for 5 consecutive days). A blinded evaluator rated the pain using the visual analogue scale for pain, Clinician Global Impression and Patient Global Assessment. Safety was assessed with a neuropsychological battery and confounders with the evaluation of depression and anxiety changes. There was a significant pain improvement after active anodal stimulation of the motor cortex, but not after sham stimulation. These results were not confounded by depression or anxiety changes. Furthermore, cognitive performance was not significantly changed throughout the trial in both treatment groups. The results of our study suggest that this new approach of cortical stimulation can be effective to control pain in patients with spinal cord lesion. We discuss potential mechanisms for pain amelioration after tDCS, such as a secondary modulation of thalamic nuclei activity.     

Using non-invasive brain stimulation to augment motor training-induced plasticity

Therapies for motor recovery after stroke or traumatic brain injury are still not satisfactory. To date the best approach seems to be the intensive physical therapy. However the results are limited and functional gains are often minimal. The goal of motor training is to minimize functional disability and optimize functional motor recovery. This is thought to be achieved by modulation of plastic changes in the brain. Therefore, adjunct interventions that can augment the response of the motor system to the behavioural training might be useful to enhance the therapy-induced recovery in neurological populations. In this context, noninvasive brain stimulation appears to be an interesting option as an add-on intervention to standard physical therapies. Two non-invasive methods of inducing electrical currents into the brain have proved to be promising for inducing long-lasting plastic changes in motor systems: transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS). These techniques represent powerful methods for priming cortical excitability for a subsequent motor task, demand, or stimulation. Thus, their mutual use can optimize the plastic changes induced by motor practice, leading to more remarkable and outlasting clinical gains in rehabilitation. In this review we discuss how these techniques can enhance the effects of a behavioural intervention and the clinical evidence to date.     

Pergolide increases the efficacy of cathodal direct current stimulation to reduce the amplitude of laser-evoked potentials in humans

Transcranial direct current stimulation (tDCS) was recently reintroduced as a tool for inducing relatively long-lasting changes in cortical excitability in focal brain regions. Anodal stimulation over the primary motor cortex enhances cortical excitability, whereas cathodal stimulation decreases it. Prior studies have shown that enhancement of D2 receptor activity by pergolide consolidates tDCS-generated excitability diminution for up to 24 hours and that cathodal stimulation of the primary motor cortex diminishes experimentally induced pain sensation and reduces the N2-P2 amplitude of laser-evoked potentials immediately poststimulation. In the present study, we investigated the effect of pergolide and cathodal tDCS over the primary motor cortex on laser-evoked potentials and acute pain perception induced with a Tm:YAG laser in a double-blind, randomized, placebo-controlled, crossover study. The amplitude changes of laser-evoked potentials and subjective pain rating scores of 12 healthy subjects were analyzed prior to and following 15 minutes cathodal tDCS combined with pergolide or placebo intake at five different time points. Our results indicate that the amplitude of the N2 component was significantly reduced following cathodal tDCS for up to two hours. Additionally, pergolide prolonged the effect of the cathodal tDCS for up to 24 hours, and a significantly lowered pain sensation was observed for up to 40 minutes. Our study is a further step toward clinical application of cathodal tDCS over the primary motor cortex using pharmacological intervention to prolong the excitability-diminishing effect on pain perception for up to 24 hours poststimulation. Furthermore, it demonstrates the potential for repetitive daily stimulation therapy for pain patients.     

Motor evoked potentials

Noninvasive electrical stimulation of the human brain first was attempted in the 1950s. In the early 1980s, the first clinical application method of transcranial electrical stimulation was developed. Investigators in the mid-1980s showed that it was possible to stimulate the nerve and the brain using external magnetic stimulation (transcranial magnetic stimulation [TMS]), with little or no pain. TMS now is used commonly in clinical neurology to study central motor conduction time. Depending on the stimulation techniques and parameters, TMS can excite or inhibit brain activity, allowing functional mapping of cortical regions and creation of transient functional lesions. It now is used widely as a research tool to study aspects of human brain physiology, including motor function and the pathophysiology of various brain disorders.     

tDCS modulates cortical nociceptive processing but has little to no impact on pain perception

Transcranial direct current stimulation (tDCS) effectively modulates cortical excitability. Several studies suggest clinical efficacy in chronic pain syndromes. However, little is known regarding its effects on cortical pain processing. In this double-blind, randomized, cross-over, sham controlled study, we examined the effects of anodal, cathodal, and sham stimulation of the left motor cortex in 16 healthy volunteers using functional imaging during an acute heat pain paradigm as well as pain thresholds, pain intensity ratings, and quantitative sensory testing. tDCS was applied at 1 mA for 15 minutes. Neither cathodal nor anodal tDCS significantly changed brain activation in response to nociceptive stimulation when compared with sham stimulation. However, contrasting the interaction of stimulation modes (anodal/cathodal) resulted in a significant decrease of activation in the hypothalamus, inferior parietal cortex, inferior parietal lobule, anterior insula, and precentral gyrus, contralateral to the stimulation site after anodal stimulation, which showed the opposite behavior after cathodal stimulation. Pain ratings and heat hyperalgesia showed only a subclinical pain reduction after anodal tDCS. Larger-scale clinical trials using higher tDCS intensities or longer durations are necessary to assess the neurophysiological effect and subsequently the therapeutic potential of tDCS.     

Modulating the brain at work using noninvasive transcranial stimulation

This paper proposes a shift in the way researchers currently view and use transcranial brain stimulation technologies. From a neuroscience perspective, the standard application of both transcranial magnetic stimulation (TMS) and transcranial direct current stimulation (tDCS) has been mainly to explore the function of various brain regions. These tools allow for noninvasive and painless modulation of cortical tissue. In the course of studying the function of an area, many studies often report enhanced performance of a task during or following the stimulation. However, little follow-up research is typically done to further explore these effects. Approaching this growing pool of cognitive neuroscience literature with a neuroergonomics mindset (i.e., studying the brain at work), the possibilities of using these stimulation techniques for more than simply investigating the function of cortical areas become evident. In this paper, we discuss how cognitive neuroscience brain stimulation studies may complement neuroergonomics research on human performance optimization. And, through this discussion, we hope to shift the mindset of viewing transcranial stimulation techniques as solely investigatory basic science tools or possible clinical therapeutic devices to viewing transcranial stimulation techniques as interventional tools to be incorporated in applied science research and systems for the augmentation and enhancement of human operator performance.     

Noninvasive cortical modulation of experimental pain

Noninvasive cortical stimulation (NICS) can produce analgesic effects by means of repetitive transcranial magnetic stimulation or transcranial direct current stimulation (tDCS). Such effects have been demonstrated on chronic ongoing pain, as in acute provoked pain. The investigation of induced changes in the perception of experimental pain by NICS could help clinicians and researchers to better understand the mechanisms of action involved with these techniques and the role played by the cortex in the integration of nociceptive information. This review presents current literature data on the modulation of experimental pain perception by cortical stimulation. The observations found that NICS analgesic effects depend on the method used to provoke pain (referring to the type of nerve fibers and neural circuits that are recruited to mediate pain) and the parameters of cortical stimulation (especially the nature of the cortical target). The motor cortex (precentral cortical area) is the most widely used target for pain modulation. However, other targets, such as the dorsolateral prefrontal cortex, could be of particular interest to modulate various components of pain. Further developments in NICS techniques, such as image-guided navigated brain stimulation, might lead to improvement in the beneficial effects of NICS on pain. Finally, we discuss whether the results obtained in experimental pain can be transposed to the problem of chronic pain and whether they can be used to optimize cortical stimulation therapy for pain disorders.     

Effects of motor cortex modulation and descending inhibitory systems on pain thresholds in healthy subjects

Pain modulation can be achieved using neuromodulatory tools that influence various levels of the nervous system. Transcranial direct current stimulation (tDCS), for instance, has been shown to reduce chronic pain when applied to the primary motor cortex. In contrast to this central neuromodulatory technique, diffuse noxious inhibitory controls (DNIC) refers to endogenous analgesic mechanisms that decrease pain following the introduction of heterotopic noxious stimuli. We examined whether combining top-down motor cortex modulation using anodal tDCS with a bottom-up DNIC induction paradigm synergistically increases the threshold at which pain is perceived. The pain thresholds of 15 healthy subjects were assessed before and after administration of active tDCS, sham tDCS, cold-water-induced DNIC, and combined tDCS and DNIC. We found that both tDCS and the DNIC paradigm significantly increased pain thresholds and that these approaches appeared to have additive effects. Increase in pain threshold following active tDCS was positively correlated with baseline N-acetylaspartate in the cingulate cortex and negatively correlated with baseline glutamine levels in the thalamus as measured by magnetic resonance spectroscopy. These results suggest that motor cortex modulation may have a greater analgesic effect when combined with bottom-up neuromodulatory mechanisms, presenting new avenues for modulation of pain using noninvasive neuromodulatory approaches. PERSPECTIVE: This article demonstrates that both noninvasive motor cortex modulation and a descending noxious inhibitory controls paradigm significantly increase pain thresholds in healthy subjects and appear to have an additive effect when combined. These results suggest that existing pain therapies involving DNIC may be enhanced through combination with noninvasive brain stimulation.     

Motor and parietal cortex stimulation for phantom limb pain and sensations

Limb amputation may lead to chronic painful sensations referred to the absent limb, ie phantom limb pain (PLP), which is likely subtended by maladaptive plasticity. The present study investigated whether transcranial direct current stimulation (tDCS), a noninvasive technique of brain stimulation that can modulate neuroplasticity, can reduce PLP. In 2 double-blind, sham-controlled experiments in subjects with unilateral lower or upper limb amputation, we measured the effects of a single session of tDCS (2 mA, 15 min) of the primary motor cortex (M1) and of the posterior parietal cortex (PPC) on PLP, stump pain, nonpainful phantom limb sensations and telescoping. Anodal tDCS of M1 induced a selective short-lasting decrease of PLP, whereas cathodal tDCS of PPC induced a selective short-lasting decrease of nonpainful phantom sensations; stump pain and telescoping were not affected by parietal or by motor tDCS. These findings demonstrate that painful and nonpainful phantom limb sensations are dissociable phenomena. PLP is associated primarily with cortical excitability shifts in the sensorimotor network; increasing excitability in this system by anodal tDCS has an antalgic effect on PLP. Conversely, nonpainful phantom sensations are associated to a hyperexcitation of PPC that can be normalized by cathodal tDCS. This evidence highlights the relationship between the level of excitability of different cortical areas, which underpins maladaptive plasticity following limb amputation and the phenomenology of phantom limb, and it opens up new opportunities for the use of tDCS in the treatment of PLP.     

Measuring and manipulating brain connectivity with resting state functional connectivity magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS)

Both resting state functional magnetic resonance imaging (fcMRI) and transcranial magnetic stimulation (TMS) are increasingly popular techniques that can be used to non-invasively measure brain connectivity in human subjects. TMS shows additional promise as a method to manipulate brain connectivity. In this review we discuss how these two complimentary tools can be combined to optimally study brain connectivity and manipulate distributed brain networks. Important clinical applications include using resting state fcMRI to guide target selection for TMS and using TMS to modulate pathological network interactions identified with resting state fcMRI. The combination of TMS and resting state fcMRI has the potential to accelerate the translation of both techniques into the clinical realm and promises a new approach to the diagnosis and treatment of neurological and psychiatric diseases that demonstrate network pathology.     

Effects of Anodal Transcranial Direct Current Stimulation on Chronic Neuropathic Pain in Patients With Multiple Sclerosis

Neuropathic pain in patients with MS is frequent and is associated with a great interference with daily life activities. In the present study, we investigated whether anodal transcranial direct current stimulation (tDCS) may be effective in reducing central chronic pain in MS patients. Patients received sham tDCS or real tDCS in a 5-day period of treatment in a randomized, double blind, sham-controlled study. Pain was measured using visual analog scale (VAS) for pain and the short form McGill questionnaire (SF-MPQ). Quality of life was measured using the Multiple Sclerosis Quality of Life-54 scale (MSQoL-54). Depressive symptoms and anxiety were also evaluated as confounding factors using the Beck Depression Inventory (BDI) and VAS for anxiety. Evaluations were performed at baseline, immediately after the end of treatment, and once a week during a 3-week follow-up period. Following anodal but not sham tDCS over the motor cortex, there was a significant pain improvement as assessed by VAS for pain and McGill questionnaire, and of overall quality of life. No depression or anxiety changes were observed. Our results show that anodal tDCS is able to reduce pain-scale scores in MS patients with central chronic pain and that this effect outlasts the period of stimulation, leading to long-lasting clinical effects.PerspectiveThis article presents a new, noninvasive therapeutic approach to chronic, central neuropathic pain in multiple sclerosis, poorly responsive to current conventional medications. tDCS is known to cause long-lasting changes of neuronal excitability at the site of stimulation and in the connected areas in healthy subjects. This led us to hypothesize that pain decrease may be the result of functional plastic changes in brain structures involved in the pathogenesis of chronic neuropathic pain.     

Anodal Transcranial Direct Current Stimulation Reduces Secondary Hyperalgesia Induced by low Frequency Electrical Stimulation in Healthy Volunteers

The aim of the study was to determine whether transcranial direct current stimulation (tDCS) reduced pain and signs of central sensitization induced by low frequency electrical stimulation in healthy volunteers. Thirty-nine participants received tDCS stimulation under 4 different conditions: anodal tDCS of the primary motor cortex (M1), anodal tDCS of the dorsolateral prefrontal cortex (DLPFC), anodal tDCS over M1 and DLPFC concurrently, and sham tDCS. Participants were blind to the tDCS condition. The order of the conditions was randomized among participants. Pain ratings to pinpricks, the current level that evoked moderate pain, and pain induced by low frequency electrical stimulation were assessed in the forearm by an experimenter who was blind to the tDCS conditions. Anodal tDCS at M1 increased the current level that evoked moderate pain compared to sham and other conditions. Anodal tDCS of DLPFC completely abolished secondary hyperalgesia. Unexpectedly, however, concurrent anodal tDCS over M1 and DLPFC did not reduce pain or hyperalgesia more than M1 alone or DLPFC alone. Overall, these findings suggest that anodal tDCS over M1 suppresses pain, and that anodal tDCS over DLPFC modulates secondary hyperalgesia (a sign of central sensitization) in healthy participants.PerspectiveAnodal transcranial current stimulation (atDCS) at the left motor cortex and the dorsolateral prefrontal cortex increased the electrically-evoked pain threshold and reduced secondary hyperalgesia in healthy participants. Replication of this study in chronic pain populations may open more avenues for chronic pain treatment.     

Pain relief for osteoarthritis through combined treatment (PROACT): Protocol for a randomized controlled trial of mindfulness meditation combined with transcranial direct current stimulation in non-Hispanic black and white adults with knee osteoarthritis

Knee osteoarthritis (OA) is a leading cause of late life pain and disability, and non-Hispanic black (NHB) adults experience greater OA-related pain and disability than non-Hispanic whites (NHWs). Recent evidence implicates psychosocial stress, cognitive-attentional processes, and altered central pain processing as contributors to greater OA-related pain and disability among NHBs. To address these ethnic/race disparities, this clinical trial will test whether a mindfulness intervention (Breathing and Attention Training, BAT) combined with transcranial direct current stimulation (tDCS) will enhance pain modulatory balance and pain-related brain function, reduce clinical pain, and attenuate ethnic differences therein, among NHBs and NHWs with knee OA. Participants will complete assessments of clinical pain, function, psychosocial measures, and quantitative sensory testing (QST), including mechanical temporal summation and conditioned pain modulation. Neuroimaging will be performed to examine pain-related brain structure and function. Then, participants will be randomized to one of four groups created by crossing two BAT conditions (Real vs. Sham) with two tDCS conditions (Real vs. Sham). Participants will then undergo five treatment sessions during which the assigned BAT and tDCS interventions will be delivered concurrently for 20 min over one week. After the fifth intervention session, participants will undergo assessments of clinical pain and function, QST and neuroimaging identical to the pretreatment measures, and monthly follow-up assessments of pain will be conducted for three months. This will be the first study to determine whether mindfulness and tDCS treatments will show additive or synergistic effects when combined, and whether treatment effects differ across ethnic/race groups.     

Motor Cortex Stimulation for Deafferentation Pain

Purpose of Review

Since the early 1990s, motor cortex stimulation (MCS) has been a unique treatment modality for patients with drug-resistant deafferentation pain. While underpowered studies and case reports have limited definitive, data-driven analysis of MCS in the past, recent research has brought new clarity to the MCS literature and has helped identify appropriate indications for MCS and its long-term efficacy.

Recent Findings

In this review, new research in MCS, repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS) are analyzed and compared with historical landmark papers. Currently, MCS is effective in providing relief to 40–64% of patients, with decreasing analgesic effect over time addressed by altering stimulation settings. rTMS and tDCS, two historic, non-invasive stimulation techniques, are providing new alternatives for the treatment of deafferentation pain, with rTMS finding utility in identifying MCS responders. Future advances in electrode arrays, neuro-navigation, and high-definition tDCS hold promise in providing pain relief to growing numbers of patients.

Summary

Deafferentation pain is severe, disabling, and remains a challenge for patients and providers alike. Over the last several years, the MCS literature has been revitalized with studies and meta-analyses demonstrating MCS effectiveness and providing guidance in identifying responders. At the same time, rTMS and tDCS, two time-honored non-invasive stimulation techniques, are finding new utility in managing deafferentation pain and identifying good MCS candidates. As the number of potential therapies grow, the clinician’s role is shifting to personalizing treatment to the unique pain of each patient. With new treatment modalities, this form of personalized medicine is more possible than ever before.

     

Effects of transcranial direct current stimulation on pain perception and working memory

Previous studies have shown that non‐invasive stimulation of the dorsolateral prefrontal cortex (DLPFC) could modulate experimentally induced pain and working memory (WM) in healthy subjects. However, the two aspects have never been assessed concomitantly. The present study was set up to investigate the effects of transcranial direct current stimulation (tDCS) of the DLPFC on thermal pain and WM in the same population of healthy volunteers. In a randomized and balanced order of different sessions separated by 1 week, 20 min of 2 mA anodal, cathodal or sham tDCS were applied to the left or right DLPFC in two separate experiments. Twelve healthy volunteers were enrolled for each stimulated hemisphere. Warm and cold detection thresholds, heat and cold pain thresholds as well as heat pain tolerance thresholds were measured before, during and following tDCS. WM was assessed by a 2‐back task applied once during cortical stimulation. Anodal tDCS of the right DLPFC led to an increase of tolerance to heat pain. The 2‐back task revealed fewer outliers during cathodal tDCS of the left DLPFC. The present data show an involvement of the DLPFC in the processing of pain and WM. There was no correlation between these findings, suggesting that the analgesic effects of cortical stimulation are not associated with cognitive processing. However, this conclusion is difficult to affirm because of some limitations of the study regarding the parameters of stimulation or a ceiling effect of the 2‐back task for instance.     

A pilot study of the tolerability and effects of high-definition transcranial direct current stimulation (HD-tDCS) on pain perception

Several brain stimulation technologies are beginning to evidence promise as pain treatments. However, traditional versions of 1 specific technique, transcranial direct current stimulation (tDCS), stimulate broad regions of cortex with poor spatial precision. A new tDCS design, called high definition tDCS (HD-tDCS), allows for focal delivery of the charge to discrete regions of the cortex. We sought to preliminarily test the safety and tolerability of the HD-tDCS technique as well as to evaluate whether HD-tDCS over the motor cortex would decrease pain and sensory experience. Twenty-four healthy adult volunteers underwent quantitative sensory testing before and after 20 minutes of real (n = 13) or sham (n = 11) 2 mA HD-tDCS over the motor cortex. No adverse events occurred and no side effects were reported. Real HD-tDCS was associated with significantly decreased heat and cold sensory thresholds, decreased thermal wind-up pain, and a marginal analgesic effect for cold pain thresholds. No significant effects were observed for mechanical pain thresholds or heat pain thresholds. HD-tDCS appears well tolerated, and produced changes in underlying cortex that are associated with changes in pain perception. Future studies are warranted to investigate HD-tDCS in other applications, and to examine further its potential to affect pain perception. PERSPECTIVE: This article presents preliminary tolerability and efficacy data for a new focal brain stimulation technique called high definition transcranial direct current stimulation. This technique may have applications in the management of pain.     

经颅直流电刺激结合功能性电刺激对脑卒中平台期患者上肢运动功能康复影响的研究

目的:将经颅直流电刺激(tDCS)和功能性电刺激(FES)结合,观察这种联合治疗干预方式对脑卒中平台期患者上肢功能的影响。方法:3例脑卒中后平台期偏瘫患者在4周基线期后接受4周的tDCS结合FES治疗干预。干预前后用Fugl-Meyer上肢运动功能评分(U-FMA)、表面肌电图(sEMG)、经颅磁刺激(TMS)进行评定。结果:干预后U-FMA分数较干预前提高。7个主动肌中有5个表面肌电激活性干预前后有明显变化。用TMS成对刺激方法评估受试者健侧大脑短潜伏期皮质内抑制与短潜伏期皮质内易化结果显示部分的干预前后变化。结论:tDCS结合FES治疗干预改善了受试者上肢的运动功能,该方案可能是针对脑卒中平台期患者的一种有前景的干预康复方案。