Effect of different non-pharmacologic placebo treatments on migraine prevention: a network meta-analysis of randomized controlled trials

BACKGROUND

Placebo control plays an important role in evaluating the effectiveness of interventions. Specifying differential effects of various placebo controls on migraine prevention would be essential in the explanation of preventive treatment for migraine and the indirect comparison between different prophylactic therapeutics.

OBJECTIVES

To access the impact of different non-pharmacologic placebo types on different outcomes in migraine patients.

METHODS

We searched PubMed, Cochrane Controlled Register of Trials, Embase, and Web of Science databases from the date of creation to June 19, 2023. Randomized controlled trials of migraine that included sham intervention of acupuncture or cognitive behavioural therapy (CBT) or non-invasive Vagus Nerve Stimulation (nVNS) or repetitive Transcranial Magnetic Stimulation (rTMS) or transcranial Direct Current Stimulation (tDCS) were conducted. The primary outcome was the migraine days, and the secondary outcomes were the number of migraine attacks, headache days, headache frequency, and responder's rate. Placebo effects were assessed using five individual placebos for network meta-analysis, using mean differences to measure the relative effect of pair-wise comparisons between interventions.

RESULT

A total of 50 trials with 4880 subjects were included. Twenty-seven trials were evaluated for low risk of bias. The results of indirect comparisons show that sham rTMS and sham tDCS had optimal and similar effects in reducing migraine days; sham acupuncture has the greatest effect on reducing the number of migraine attacks and relieving headache frequency; sham rTMS had a highly significant advantage in reducing headache days compared with the other placebo controls.

CONCLUSION

Based on the network meta-analysis results, we found that sham acupuncture had the greatest effect on migraine prophylaxis. The strong placebo effect of sham acupuncture should be considered when assessing the therapeutic effect.

Non-Pharmacological Treatment for Chronic Migraine

PURPOSE OF REVIEW

Chronic migraine (CM) affects a large proportion of the population and is a significant source of disability and lost productivity. Numerous non-pharmacological approaches have been attempted during the past decades. This review discusses the most recent and evidence-based advances in acute and preventive non-pharmacological therapeutic approaches for CM, offering alternatives to drug treatment.

RECENT FINDINGS

A growing number of non-pharmacological treatment options, including non-invasive or invasive neuromodulation, acupuncture, psychotherapy, and physiotherapy, have shown promising efficacy in CM. There is strong evidence for the effectiveness of non-invasive neuromodulation such as transcranial magnetic stimulation, transcranial direct current stimulation, and transcutaneous electrical nerve stimulation (TENS) in CM, but less evidence for approaches such as invasive neuromodulation, physical therapy, or dietary approaches. Acupuncture for migraine remains controversial, with the main point of contention still being the placebo effect. Non-pharmacological approaches can be offered as a reliable alternative for patients with CM, and more research is being done to evaluate the efficacy of non-invasive neuromodulation with different parameters and the combination of different treatments in CM.

Neurostimulation for Chronic Pain: A Systematic Review of High-Quality Randomized Controlled Trials With Long-Term Follow-Up

OBJECTIVE

This study aimed to review the best evidence on the long-term efficacy of neurostimulation for chronic pain.

MATERIALS AND METHODS

We systematically reviewed PubMed, CENTRAL, and WikiStim for studies published between the inception of the data bases and July 21, 2022. Randomized controlled trials (RCTs) with a minimum of one-year follow-up that were of high methodologic quality as ascertained using the Delphi list criteria were included in the evidence synthesis. The primary outcome was long-term reduction in pain intensity, and the secondary outcomes were all other reported outcomes. Level of recommendation was graded from I to III, with level I being the highest level of recommendation.

RESULTS

Of the 7119 records screened, 24 RCTs were included in the evidence synthesis. Therapies with recommendations for their usage include pulsed radiofrequency (PRF) for postherpetic neuralgia, transcutaneous electrical nerve stimulation for trigeminal neuralgia, motor cortex stimulation for neuropathic pain and poststroke pain, deep brain stimulation for cluster headache, sphenopalatine ganglion stimulation for cluster headache, occipital nerve stimulation for migraine, peripheral nerve field stimulation for back pain, and spinal cord stimulation (SCS) for back and leg pain, nonsurgical back pain, persistent spinal pain syndrome, and painful diabetic neuropathy. Closed-loop SCS is recommended over open-loop SCS for back and leg pain. SCS is recommended over PRF for postherpetic neuralgia. Dorsal root ganglion stimulation is recommended over SCS for complex regional pain syndrome.

CONCLUSIONS

Neurostimulation is generally effective in the long term as an adjunctive treatment for chronic pain. Future studies should evaluate whether the multidisciplinary management of the physical perception of pain, affect, and social stressors is superior to their management alone.

[Using electricity to combat headache : Electrotherapy and tDCS in the 1870s/1880s and today]

Headache can be a widespread symptom as well as a disorder in itself. Headache syndromes such as migraine cause a lot of distress, disability and overall socioeconomic costs. Pharmacological treatments are often limited in their efficacy as well as due to side effects. The therapeutic application of electricity for this medical indication was a relevant field of research in the 19th century and-in the form of transcranial direct current stimulation (tDCS)-is still widely studied today. This paper provides an overview of publications from the late 19th century (as the era of discovery and success of electrotherapy) as well as contemporary studies investigating the usage of weak currents for the treatment or prophylaxis of headache. Our results show a large number of highly favorable reports of treatment successes. However, the number of cases analysed is often rather small and the forms of electric stimulation applied were often highly heterogeneous. In summary, electric stimulation appears to be a promising field of research and a possible therapeutic agent for the treatment of headaches; however, further research is necessary, especially into the details of the stimulation techniques applied and the various indications in which it may be of use.

Non-invasive brain stimulation treatments for migraine prophylaxis: a network meta-analysis of randomized controlled trials

BACKGROUND AND OBJECTIVES

Migraine is a major public health problem owing to its long disease duration and disease relapse. Non-invasive brain stimulation treatments were reported effective for the management of migraine, but the comparative effectiveness of three main NIBSs, rTMS, nVNS, and tDCS, has not been studied. We aimed to explore the relative efficacy of rTMS, tDCS, and nVNS in migraine prophylaxis by using network meta-analysis (NMA).

METHODS

We searched OVID Medline, Embase, Cochrane Controlled Register of Trials, and Web of Science from inception to 1 January 2022. Randomized controlled trials that reported the efficacy of rTMS, tDCS or nVNS in the prophylactic treatment of migraine were included. The primary outcome was monthly migraine frequency, and secondary outcomes were headache intensity and the impact of headaches on daily life. The relative effects of the treatments in contrast to the others were measured by using standard mean difference (SMD).

RESULTS

We included 31 trials with 1659 participants. Fourteen trials were rated as low risk of bias. The results showed that tDCS (SMD - 1.58; 95%CI, - 2.38 to  - 0.79; P-score = 0.92) had the largest effect on migraine frequency when compared with sham interventions in reducing monthly migraine frequency, and tDCS had a larger effect than rTMS (SMD - 0.62; 95%CI, - 1.81 to 0.57) and nVNS (SMD - 1.39; 95%CI, - 3.27 to 0.49). tDCS had also the largest effect in reducing pain intensity when compared with sham intervention (SMD - 1.49; 95%CI, - 2.46 to  - 0.52) and rTMS (SMD - 0.48; 95%CI, - 2.06 to 1.09).

CONCLUSIONS

For the prophylactic treatment of migraine, tDCS was relatively more effective than rTMS and nVNS. Head-to-head comparison trials are needed to confirm the findings.

Primary headache disorders: From pathophysiology to neurostimulation therapies

Primary headache disorders including migraine, cluster headache, and tension-type headache are among the most common disabling diseases worldwide. The unclear pathogenesis of primary headache disorders has led to high rates of misdiagnosis and limited available treatment options. In this review, we have summarized the pathophysiological factors for a better understanding of primary headache disorders. Advances in functional neuroimaging, genetics, neurophysiology have indicated that cortical hyperexcitability, regional brain dysfunction, central sensitization and neuroplasticity changes play vital roles in the development of primary headache disorders. Moreover, we have also discussed a series of neurostimulation approaches with their stimulation mechanism, safety and efficacy for prevention and treatment of primary headache disorders. Noninvasive or implantable neurostimulation techniques show great promise for treating refractory primary headache disorders.

Transcranial Direct Current Stimulation for Chronic Stroke: Is Neuroimaging the Answer to the Next Leap Forward?

During rehabilitation, a large proportion of stroke patients either plateau or begin to lose motor skills. By priming the motor system, transcranial direct current stimulation (tDCS) is a promising clinical adjunct that could augment the gains acquired during therapy sessions. However, the extent to which patients show improvements following tDCS is highly variable. This variability may be due to heterogeneity in regions of cortical infarct, descending motor tract injury, and/or connectivity changes, all factors that require neuroimaging for precise quantification and that affect the actual amount and location of current delivery. If the relationship between these factors and tDCS efficacy were clarified, recovery from stroke using tDCS might be become more predictable. This review provides a comprehensive summary and timeline of the development of tDCS for stroke from the viewpoint of neuroimaging. Both animal and human studies that have explored detailed aspects of anatomy, connectivity, and brain activation dynamics relevant to tDCS are discussed. Selected computational works are also included to demonstrate how sophisticated strategies for reducing variable effects of tDCS, including electric field modeling, are moving the field ever closer towards the goal of personalizing tDCS for each individual. Finally, larger and more comprehensive randomized controlled trials involving tDCS for chronic stroke recovery are underway that likely will shed light on how specific tDCS parameters, such as dose, affect stroke outcomes. The success of these collective efforts will determine whether tDCS for chronic stroke gains regulatory approval and becomes clinical practice in the future.

Medication overuse headache

Medication overuse headache (MOH) is a secondary headache disorder attributed to overuse of acute headache medications by a person with an underlying headache disorder, usually migraine or tension-type headache. MOH is common among individuals with 15 or more headache days per month. Although MOH is associated with substantial disability and reductions in quality of life, this condition is often under-recognized. As MOH is both preventable and treatable, it warrants greater attention and awareness. The diagnosis of MOH is based on the history and an unremarkable neurological examination, and is made according to the diagnostic criteria of the International Classification of Headache Disorders third edition (ICHD-3). Pathophysiological mechanisms of MOH include altered descending pain modulation, central sensitization and biobehavioural factors. Treatment of MOH includes the use of headache preventive therapies, but essential to success is eliminating the cause, by reducing the frequency of use of acute headache medication, and perhaps withdrawing the overused medication altogether. Appropriate treatment is usually highly effective, leading to reduced headache burden and acute medication consumption.

Transcranial direct current stimulation for migraine: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) is a promising method for migraine treatment. In this study, we investigated the efficacy and safety of tDCS for migraine by conducting a systematic review and meta-analysis of randomized controlled trials (RCTs).

METHODS

We searched PubMed, EMBASE, Cochrane Library, and Web of Science up to December 02, 2021 for RCTs reporting tDCS for migraine treatment. Two authors independently evaluated the eligibility of the retrieved trials and extracted relevant data. Outcomes for the quantitative synthesis were reduction in migraine days per month and adverse events.

RESULTS

Eleven RCTs that included 425 patients with migraine were evaluated in the meta-analysis. The efficacy and safety of anodal or cathodal stimulation targeting different brain areas, including primary motor cortex (M1), primary sensory cortex (S1), dorsolateral prefrontal cortex (DLPFC), and visual cortex (VC), were assessed in the RCTs enrolled. We found that tDCS with M1 and VC activation could reduce No. of migraine days per month in patients with migraine. Meanwhile, tDCS with VC inhibition could also reduce No. of migraine days per month in patients with migraine. However, there were no differences in the incidence of adverse events between the two groups.

CONCLUSION

tDCS activates M1 or activates/inhibits VC which could improve migraine symptoms. tDCS is an effective, preventive, and safe treatment for migraine.

Effectiveness of Transcranial Direct Current Stimulation and Monoclonal Antibodies Acting on the CGRP as a Combined Treatment for Migraine (TACTIC): Protocol for a Randomized, Double-Blind, Sham-Controlled Trial

Background

Migraine is a recurrent headache disorder that has a still unclear pathophysiology, involving several circuits of both the central and peripheral nervous system. Monoclonal antibodies acting on the calcitonin gene-related (CGRP) pathway (CGRP-MAbs) are the first drugs specifically designed for migraine; those drugs act peripherally on the trigeminal ganglion without entering the blood-brain barrier. Conversely, neuromodulation techniques such as transcranial direct current stimulation (tDCS) act centrally by increasing or decreasing the neuronal firing rate of brain cortical areas. The aim of the study will be to evaluate whether tDCS, in addition to CGRP-MAbs, is an effective add-on treatment in reducing headache frequency, intensity and acute medication use in patients with migraine. To demonstrate the biological effects of tDCS, the electroencephalographic (EEG) power changes after tDCS will be assessed.

Methods

We will include patients with migraine on treatment with CGRP-MAbs and reporting ≥8 monthly migraine days. During a prospective 28-day baseline period, patients will fill in a headache diary and questionnaires to evaluate migraine-related disability, anxiety and depressive symptoms, sleep quality, and health-related quality of life. Subjects will be randomly assigned in a 1:1 ratio to active or sham tDCS. The stimulation protocol will consist in five daily sessions, the cathodes will be applied bilaterally above the occipital areas, with the reference anode electrodes positioned above the primary motor areas. Before the first, and immediately after the last stimulation session, patients will perform a 10-min resting EEG recording. During a 28-day follow-up period following tDCS, patients will have to fill in a headache diary and questionnaires identical to those of the baseline period.

Discussion

This trial will evaluate the efficacy of an add-on treatment acting on the brain in patients with migraine, who are already treated with peripherally acting drugs, showing how tDCS acts in restoring the dysfunctional brain networks typical of the migraine patient.

Clinical Trial Registration

NCT05161871.

Determining the Effects of Transcranial Direct Current Stimulation on Tinnitus, Depression, and Anxiety: A Systematic Review

(1) Background: Tinnitus is the awareness of a sound in the absence of an external source. It affects around 10–15% of people, a significant proportion of whom also experience symptoms such as depression or anxiety that negatively affect their quality of life. Transcranial direct current stimulation (tDCS) is a technique involving constant low-intensity direct current delivered via scalp electrodes. It is a potential treatment option for tinnitus, as well as tinnitus-related conditions such as depression and anxiety. This systematic review estimates the effects of tDCS on outcomes relevant to tinnitus. In addition, it sheds light on the relationship between stimulation parameters and the effect of tDCS on these outcomes; (2) Methods: Exhaustive searches of electronic databases were conducted. Randomised controlled trials were included if they reported at least one of the following outcomes: tinnitus symptom severity, anxiety, or depression. Where available, data on quality of life, adverse effects, and neurophysiological changes were also reviewed. GRADE was used to assess the certainty in the estimate; (3) Results: Meta-analyses revealed a statistically significant reduction in tinnitus (moderate certainty) and depression (low certainty)-but not anxiety-following active tDCS compared to sham control. Network meta-analyses revealed potential optimal stimulation parameters; (4) Conclusions: The evidence synthesised in this review suggests tDCS has the potential to reduce symptom severity in tinnitus and depression. It further narrows down the number of potentially optimal stimulation parameters.

Effectiveness and acceptability of noninvasive brain and nerve stimulation techniques for migraine prophylaxis: a network meta-analysis of randomized controlled trials

BACKGROUND

Current pharmacologic prophylactic strategies for migraine have exhibited limited efficacy, with response rates as low as 40%-50%. In addition to the limited efficacy, the acceptability of those pharmacologic prophylactic strategies were unacceptable. Although noninvasive brain/nerve stimulation strategies may be effective, the evidence has been inconsistent. The aim of this network meta-analysis (NMA) was to compare strategies of noninvasive brain/nerve stimulation for migraine prophylaxis with respect to their effectiveness and acceptability.

METHODS

The PubMed, Embase, ScienceDirect, ProQuest, ClinicalTrials.gov , ClinicalKey, Cochrane CENTRAL, Web of Science, and ClinicalTrials.gov databases were systematically searched to date of June 4th, 2021 for randomized controlled trials (RCTs). Patients with diagnosis of migraine, either episodic migraine or chronic migraine, were included. All NMA procedures were conducted under the frequentist model.

RESULTS

Nineteen RCTs were included (N = 1493; mean age = 38.2 years; 82.0% women). We determined that the high frequency repetitive transcranial magnetic stimulation (rTMS) over C3 yielded the most decreased monthly migraine days among all the interventions [mean difference = - 8.70 days, 95% confidence intervals (95%CIs): - 14.45 to - 2.95 compared to sham/control groups]. Only alternating frequency (2/100 Hz) transcutaneous occipital nerve stimulation (tONS) over the Oz (RR = 0.36, 95%CIs: 0.16 to 0.82) yielded a significantly lower drop-out rate than the sham/control groups did.

CONCLUSIONS

The current study provided a new direction for the design of more methodologically robust and larger RCTs based on the findings of the potentially beneficial effect on migraine prophylaxis in participants with migraine by different noninvasive brain/nerve stimulation, especially the application of rTMS and tONS.

TRIAL REGISTRATION

CRD42021252638. The current study had been approval by the Institutional Review Board of the Tri-Service General Hospital, National Defense Medical Center (TSGHIRB No. B-109-29).

Neuromodulation for Chronic Daily Headache

Purpose of Review

We reviewed the literature that explored the use of central and peripheral neuromodulation techniques for chronic daily headache (CDH) treatment.

Recent Findings

Although the more invasive deep brain stimulation (DBS) is effective in chronic cluster headache (CCH), it should be reserved for extremely difficult-to-treat patients. Percutaneous occipital nerve stimulation has shown similar efficacy to DBS and is less risky in both CCH and chronic migraine (CM). Non-invasive transcutaneous vagus nerve stimulation is a promising add-on treatment for CCH but not for CM. Transcutaneous external trigeminal nerve stimulation may be effective in treating CM; however, it has not yet been tested for cluster headache. Transcranial magnetic and electric stimulations have promising preventive effects against CM and CCH.

Summary

Although the precise mode of action of non-invasive neuromodulation techniques remains largely unknown and there is a paucity of controlled trials, they should be preferred to more invasive techniques for treating CDH.

Which is the best transcranial direct current stimulation protocol for migraine prevention? A systematic review and critical appraisal of randomized controlled trials

BACKGROUND

Transcranial direct current stimulation (tDCS) could counteract the pathophysiological triggers of migraine attacks by modulating cortical excitability. Several pilot randomized controlled trials (RCTs) assessed the efficacy of tDCS for migraine prevention. We reviewed and summarized the state of the art of tDCS protocols for migraine prevention, discussing study results according to the stimulations parameters and patients' populations.

MAIN BODY

We combined the keywords 'migraine', 'headache', 'transcranial direct current stimulation', and 'tDCS' and searched Pubmed, Scopus, and Web of Science, from the beginning of indexing to June 22, 2021. We only included RCTs comparing the efficacy of active tDCS with sham tDCS to decrease migraine frequency, intensity, and/or acute drug utilization. The risk of bias of each RCT was assessed by using the RoB-2 tool (Cochrane Collaboration). Thirteen RCTs (from 2011 to 2021) were included in the review. The included patients ranged from 13 to 135. RCTs included patients with any migraine (n=3), chronic migraine (n=6), episodic migraine (n=3) or menstrual migraine (n=1). Six RCTs used cathodal and five anodal tDCS, while two RCTs compared the efficacy of both cathodal and anodal tDCS with that of sham. In most of the cathodal stimulation trials, the target areas were the occipital regions, with reference on central or supraorbital areas. In anodal RCTs, the anode was usually placed above the motor cortical areas and the cathode on supraorbital areas. All RCTs adopted repeated sessions (from 5 to 28) at variable intervals, while the follow-up length spanned from 1 day up to 12 months. Efficacy results were variable but overall positive. According to the RoB-2 tool, only four of the 13 RCTs had a low risk of bias, while the others presented some concerns.

CONCLUSIONS

Both anodal and cathodal tDCS are promising for migraine prevention. However, there is a need for larger and rigorous RCTs and standardized procedures. Additionally, the potential benefits and targeted neurostimulation protocols should be assessed for specific subgroups of patients.

Update of Neuromodulation in Chronic Migraine

Purpose of Review

Neuromodulation devices have become an attractive alternative to traditional pharmacotherapy for migraine, especially for patients intolerant to medication or who prefer non-pharmacological options. In the past decades, many studies demonstrated the efficacy of neuromodulation devices in patients with episodic migraine (EM). However, the benefit of these devices on chronic migraine (CM), which is typically more debilitating and refractory than EM, remains not well studied.

Recent Findings

We reviewed the literature within the last five years on using FDA-cleared and investigational devices for CM. There were eight randomized controlled trials and 15 open-label observational studies on ten neuromodulation devices.

Summary

Neuromodulation is promising for use in CM, although efficacy varies among devices or individuals. Noninvasive devices are usually considered safe with minimal adverse events. However, stimulation protocol and methodology differ between studies. More well-designed studies adhering to the guideline may facilitate FDA clearance and better insurance coverage.

Non-Invasive Neurostimulation Methods for Acute and Preventive Migraine Treatment-A Narrative Review

Neurostimulation methods have now been studied for more than 20 years in migraine treatment. They can be divided into invasive and non-invasive methods. In this narrative review, the non-invasive methods are presented. The most commonly studied and used methods are vagal nerve stimulation, electric peripheral nerve stimulation, transcranial magnetic stimulation, and transcranial direct current stimulation. Other stimulation techniques, including mechanical stimulation, play only a minor role. Nearly all methods have been studied for acute attack treatment and for the prophylactic treatment of migraine. The evidence of efficacy is poor for most procedures, since no stimulation device is based on consistently positive, blinded, controlled trials with a sufficient number of patients. In addition, most studies on these devices enrolled patients who did not respond sufficiently to oral drug treatment, and so the role of neurostimulation in an average population of migraine patients is unknown. In the future, it is very important to conduct large, properly blinded and controlled trials performed by independent researchers. Otherwise, neurostimulation methods will only play a very minor role in the treatment of migraine.

Noninvasive Neuromodulation in Headache: An Update

Background

Migraine is a common disabling primary headache condition. Although strives have been made in treatment, there remains an unmet need for safe, effective acute, and preventative treatments. The promising concept of neuromodulation of relevant neuronal targets in a noninvasive fashion for the treatment of primary headache disorders has led to the trial of numerous devices over the years.

Objective

We aimed to review the evidence on current neuromodulation treatments available for the management of primary headache disorders.

Methods

Randomized controlled trial as well as open-label and real-world studies on central and peripheral cephalic and noncephalic neuromodulation modalities in primary headaches were critically reviewed.

Results

The current evidence suggests a role of single-pulse transcranial magnetic stimulation, supraorbital nerve stimulation, and remote noncephalic electrical stimulation as migraine abortive treatments, with stronger evidence in episodic rather than in chronic migraine. Single-pulse transcranial magnetic stimulation and supraorbital nerve stimulation also hold promising evidence in episodic migraine prevention and initial positive evidence in chronic migraine prevention. More evidence should clarify the therapeutic role of the external vagus nerve stimulation and transcranial direct current stimulation in migraine. However, external vagus nerve stimulation may be effective in the acute treatment of episodic but not chronic cluster headache, in the prevention of hemicrania continua and paroxysmal hemicrania but not of short-lasting neuralgiform headache attacks. The difficulty in setting up sham-controlled studies has thus far prevented the publication of robust trials. This limitation along with the cost of these therapies has meant that their use is limited in most countries.

Conclusion

Neuromodulation is a promising nonpharmacological treatment approach for primary headaches. More studies with appropriate blinding strategies and reduction of device cost may allow more widespread approval of these treatments and in turn increase clinician's experience in neuromodulation.

Is Allodynia a Determinant Factor in the Effectiveness of Transcranial Direct Current Stimulation in the Prophylaxis of Migraine?

OBJECTIVES

Allodynia, the clinical marker of central sensitization, affects even simple daily living activities and increases the tendency for migraine to be more resistant to treatment and have a chronic course. Migraine that impairs quality of life can often be treated with variable pharmaceutical agents, but with various side effects. Transcranial direct current stimulation (tDCS) is a potential alternative treatment for migraine prophylaxis.

MATERIALS AND METHODS

Seventy-seven patients diagnosed with migraine (48 with allodynia and 29 without allodynia) were included in the study. Randomly, 41 of the 77 patients received sham stimulation and 36 patients underwent three sessions of anodal left primary motor cortex stimulation for 2 mA, 20 min. Migraine attack characteristics (frequency, severity, and duration) and analgesic drug use were followed with headache diaries for one month after the stimulation.

RESULTS

After tDCS, migraine attack frequency (p = 0.021), the number of headache days (p = 0.005), duration of attacks (p = 0.008), and symptomatic analgesic drug use (p = 0.007) decreased in patients receiving active tDCS, compared to the sham group. The therapeutic gain of tDCS was calculated as 44% (95% confidence interval [CI]: 22-60%) for headache days and 76% (95% CI: 55-86) for headache duration. Response to tDCS treatment was higher in patients without allodynia (60% vs. 24%; p = 0.028) and allodynia came out as an independent predictor of response to tDCS with logistic regression analysis. Side effects were rare and similar to the sham group.

CONCLUSIONS

tDCS is a safe, efficacious, and fast method for migraine prophylaxis. However, the administration of tDCS before allodynia occurs, that is, before central sensitization develops, will provide increased responsiveness to the treatment.

SIGNIFICANCE

tDCS is more effective before the development of allodynia, but it also improves the quality of life even after the development of allodynia.

Analgesic Effect of Noninvasive Brain Stimulation for Neuropathic Pain Patients: A Systematic Review

Introduction

The objective of this review is to systematically summarize the consensus on best practices for different NP conditions of the two most commonly utilized noninvasive brain stimulation (NIBS) technologies, repetitive transcranial magnetic stimulation (rTMS), and transcranial direct current stimulation (tDCS).

Methods

PubMed was searched according to the predetermined keywords and criteria. Only English language studies and studies published up to January 31, 2020 were taken into consideration. Meta-analyses, reviews, and systematic reviews were excluded first, and those related to animal studies or involving healthy volunteers were also excluded. Finally, 29 studies covering 826 NP patients were reviewed.

Results

The results from the 24 enrolled studies and 736 NP patients indicate that rTMS successfully relieved the pain symptoms of 715 (97.1%) NP patients. Also, five studies involving 95 NP patients (81.4%) also showed that tDCS successfully relieved NP. In the included studied, the M1 region plays a key role in the analgesic treatment of NIBS. The motor evoked potentials (MEPs), the 10–20 electroencephalography system (EEG 10/20 system), and neuro-navigation methods are used in clinical practice to locate therapeutic targets. Based on the results of the review, the stimulation parameters of rTMS that best induce an analgesic effect are a stimulation frequency of 10–20 Hz, a stimulation intensity of 80–120% of RMT, 1000–2000 pulses, and 5–10 sessions, and the most effective parameters of tDCS are a current intensity of 2 mA, a session duration of 20–30 min, and 5–10 sessions.

Conclusions

Our systematically reviewed the evidence for positive and negative responses to rTMS and tDCS for NP patient care and underscores the analgesic efficacy of NIBS in patients with NP. The treatment of NP should allow the design of optimal treatments for individual patients.

Non-Pharmacological Approaches to Headaches: Non-Invasive Neuromodulation, Nutraceuticals, and Behavioral Approaches

Significant side effects or drug interactions can make pharmacological management of headache disorders very difficult. Non-conventional and non-pharmacological treatments are becoming increasingly used to overcome these issues. In particular, non-invasive neuromodulation, nutraceuticals, and behavioral approaches are well tolerated and indicated for specific patient categories such as adolescents and pregnant women. This paper aims to present the main approaches reported in the literature in the management of headache disorders. We therefore reviewed the available literature published between 2010 and 2020 and performed a narrative presentation for each of the three categories (non-invasive neuromodulation, nutraceuticals, and behavioral therapies). Regarding non-invasive neuromodulation, we selected transcranial magnetic stimulation, supraorbital nerve stimulation, transcranial direct current stimulation, non-invasive vagal nerve stimulation, and caloric vestibular stimulation. For nutraceuticals, we selected Feverfew, Butterbur, Riboflavin, Magnesium, and Coenzyme Q10. Finally, for behavioral approaches, we selected biofeedback, cognitive behavioral therapy, relaxation techniques, mindfulness-based therapy, and acceptance and commitment therapy. These approaches are increasingly seen as a valid treatment option in headache management, especially for patients with medication overuse or contraindications to drug treatment. However, further investigations are needed to consider the effectiveness of these approaches also with respect to the long-term effects.

Mapping Assessments Instruments for Headache Disorders against the ICF Biopsychosocial Model of Health and Disability

Headache disorders have a strong impact on sufferers’ lives. However, the “content” of assessment instruments addressing concepts, such as disability and quality of life (QoL), has not comprehensively been addressed. We searched SCOPUS for research papers in which outcome measures were used in adult populations of patients with migraine, tension-type headache (TTH), and cluster headache (CH). The content of single instruments was then mapped against the International Classification of Functioning, Disability, and Health. A total of 150 papers and 26 instruments were included: 15 addressed disability or impact, two addressed work-related difficulties, and nine addressed QoL. Few instruments were commonly used across the conditions and covered domains of functioning were impact on daily life activities, homework, school, and work-related tasks, leisure time, informal and family relations, pain, emotional difficulties, energy level, and impulse control. Most of the research is based on instruments that were developed for migraine, which is critical for CH, and the impact of headache disorders on work-related activities is poorly acknowledged. Further research is needed to expand the scope of headaches impact on daily life activities, and on environmental factors relevant to headache disorders to raise knowledge on the less represented areas, e.g., TTH impact.

Neuromodulation techniques for acute and preventive migraine treatment: a systematic review and meta-analysis of randomized controlled trials

BACKGROUND

Several neuromodulation methods exists for migraine treatment. The aim of the present study was to perform a systematic review and meta-analysis of randomized controlled trials (RCTs) focusing on migraine treatment using neurostimulation methods.

METHODS

We searched Medline and Embase up to July 1, 2020 for RCTs reporting acute or preventive treatment of migraine with either non-invasive or invasive neurostimulation methods. Two researchers independently assessed the eligibility of the retrieved studies and extracted data. Outcomes for the quantitative synthesis were 2 h pain free for acute treatment and headache days per month for preventive treatment. We performed subgroup analyses by treatment (stimulation method and site of application). Estimates were pooled using random-effects meta-analysis.

RESULTS

Thirty-eight articles were included in the qualitative analysis (7 acute, 31 preventive) and 34 in the quantitative evaluation (6 acute, 28 preventive). Remote electrical neuromodulation (REN) was effective for acute treatment. Data were insufficient to draw conclusions for any other techniques (single studies). Invasive occipital nerve stimulation (ONS) was effective for migraine prevention, with a large effect size but considerable heterogeneity, whereas supra-orbital transcutaneous electrical nerve stimulation (TENS), percutaneous electrical nerve stimulation (PENS), and high-frequency repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) were effective, with small to medium effect sizes. Vagus-nerve stimulation, left prefrontal cortex rTMS, and cathodal transcranial direct current stimulation (tDCS) over the M1 had no significant effect and heterogeneity was high.

CONCLUSION

Several neuromodulation methods are of potential interest for migraine management, but the quality of the evidence is very poor. Future large and well-conducted studies are needed and could improve on the present results.

Anodal transcranial direct current stimulation in chronic migraine and medication overuse headache: A pilot double-blind randomized sham-controlled trial

OBJECTIVES

Little evidence is available on the role of transcranial direct current stimulation (tDCS) in patients affected by chronic migraine (CM) and medication overuse headache (MOH). We aim to investigate the effects of tDCS in patients with CM and MOH as well as its role on brain activity.

METHODS

Twenty patients with CM and MOH were hospitalized for a 7-day detoxification treatment. Upon admission, patients were randomly assigned to anodal tDCS or sham stimulation delivered over the primary motor cortex contralateral to the prevalent migraine pain side every day for 5 days. Clinical data were recorded at baseline (T0), after 1 month (T2) and 6 months (T3). EEG recording was performed at T0, at the end of the tDCS/Sham treatment, and at T2.

RESULTS

At T2 and T3, we found a significant reduction in monthly migraine days (p = 0.001), which were more pronounced in the tDCS group when compared to the sham group (p = 0.016). At T2, we found a significant increase of alpha rhythm in occipital leads, which was significantly higher in tDCS group when compared to sham group.

CONCLUSIONS

tDCS showed adjuvant effects to detoxification in the management of patients with CM and MOH. The EEG recording showed a significant potentiation of alpha rhythm, which may represent a correlate of the underlying changes in cortico-thalamic connections.

SIGNIFICANCE

This study suggests a possible role for tDCS in the treatment of CM and MOH. The observed clinical improvement is coupled with a potentiation of EEG alpha rhythm.

Methods and strategies of tDCS for the treatment of pain: current status and future directions

INTRODUCTION

Transcranial direct current stimulation (tDCS) is a noninvasive neuromodulation technique that has been widely studied for the treatment of chronic pain. It is considered a promising and safe alternative pain therapy. Different targets have been tested, each having their own particular mechanisms for modulating pain perception.

AREAS COVERED

We discuss the current state of the art of tDCS to manage pain and future strategies to optimize tDCS' effects. Current strategies include primary motor cortex tDCS, prefrontal tDCS and tDCS combined with behavioral interventions while future strategies, on the other hand, include high-intensity tDCS, transcutaneous spinal direct current stimulation, cerebellar tDCS, home-based tDCS, and tDCS with extended number of sessions.

EXPERT COMMENTARY

It has been shown that the stimulation of the prefrontal and primary motor cortex is efficient for pain reduction while a few other new strategies, such as high-intensity tDCS and network-based tDCS, are believed to induce strong neuroplastic effects, although the underlying neural mechanisms still need to be fully uncovered. Hence, conventional tDCS approaches demonstrated promising effects to manage pain and new strategies are under development to enhance tDCS effects and make this approach more easily available by using, for instance, home-based devices.