Cathodal tDCS Guided by Thermography as Adjunctive Therapy in Chronic Migraine Patients: A Sham-Controlled Pilot Study

Neuromodulation Techniques for Headache Management

This narrative review aims to summarize evidence regarding the current utilization and future applications of neuromodulation in patients with headaches, with special attention paid to migraine and chronic cluster headache. A search was conducted in PubMed in August of 2023 to survey the current literature on neuromodulation for the treatment of headache. In total, the search yielded 1989 results, which were further filtered to include only systematic reviews published between 2022 to 2023 to capture the most up-to-date and comprehensive research on this topic. The citation lists of these articles were reviewed to find additional research on neuromodulation and supplement the results presented in this paper with primary literature. Research on the use of neuromodulation for the treatment of headache has predominantly focused on four neuromodulation techniques: peripheral nerve stimulation (PNS), transcranial magnetic stimulation (TMS), deep brain stimulation (DBS), and spinal cord stimulation (SCS). Outcome measures reported in this article include impact on migraine and headache frequency and/or pain intensity, adverse effects of the neuromodulation technique, and associated costs, when available. We found that neuromodulation has developed utility as an alternative treatment for both chronic cluster headaches and migraines, with a reduction in frequency and intensity of headache most elucidated from the articles mentioned in this review.

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.

Current Neurostimulation Therapies for Chronic Pain Conditions

PURPOSE OF REVIEW

Neurostimulation treatment options have become more commonly used for chronic pain conditions refractory to these options. In this review, we characterize current neurostimulation therapies for chronic pain conditions and provide an analysis of their effectiveness and clinical adoption. This manuscript will inform clinicians of treatment options for chronic pain.

RECENT FINDINGS

Non-invasive neurostimulation includes transcranial direct current stimulation and repetitive transcranial magnetic stimulation, while more invasive options include spinal cord stimulation (SCS), peripheral nerve stimulation (PNS), dorsal root ganglion stimulation, motor cortex stimulation, and deep brain stimulation. Developments in transcranial direct current stimulation, repetitive transcranial magnetic stimulation, spinal cord stimulation, and peripheral nerve stimulation render these modalities most promising for the alleviating chronic pain. Neurostimulation for chronic pain involves non-invasive and invasive modalities with varying efficacy. Well-designed randomized controlled trials are required to delineate the outcomes of neurostimulatory modalities more precisely.

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.

[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.

Excitation-Inhibition Imbalance in Migraine: From Neurotransmitters to Brain Oscillations

Migraine is among the most common and debilitating neurological disorders typically affecting people of working age. It is characterised by a unilateral, pulsating headache often associated with severe pain. Despite the intensive research, there is still little understanding of the pathophysiology of migraine. At the electrophysiological level, altered oscillatory parameters have been reported within the alpha and gamma bands. At the molecular level, altered glutamate and GABA concentrations have been reported. However, there has been little cross-talk between these lines of research. Thus, the relationship between oscillatory activity and neurotransmitter concentrations remains to be empirically traced. Importantly, how these indices link back to altered sensory processing has to be clearly established as yet. Accordingly, pharmacologic treatments have been mostly symptom-based, and yet sometimes proving ineffective in resolving pain or related issues. This review provides an integrative theoretical framework of excitation-inhibition imbalance for the understanding of current evidence and to address outstanding questions concerning the pathophysiology of migraine. We propose the use of computational modelling for the rigorous formulation of testable hypotheses on mechanisms of homeostatic imbalance and for the development of mechanism-based pharmacological treatments and neurostimulation interventions.

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.

Efficacy of tDCS in chronic migraine: A multiprotocol randomized controlled trial

OBJECTIVE

Given the prevalence and complicated pathophysiology of migraine, unknown or varied mechanisms of action of available monotherapies or add-on therapies, and their broad range of adverse effects, it is imperative to manage migraine symptoms using a non-invasive, multifunctional, and alternate monotherapy with no negative impacts.

METHODS

We used a single-blind, randomized, sham-controlled design with baseline, post-test, and 24-weeks follow-up measurements to assess the efficacy of transcranial Direct Current Stimulation (tDCS) in chronic migraine. A total of 150 participants were randomly assigned to the five groups (i.e., allocation ratio of 1:1:1:1:1). Each group received tDCS-intervention for 11 consecutive-weeks (25 sessions; each session = two consecutive montages; each montage = a 20 min duration, 2000 μA intensity).

RESULTS

The multivariate analysis of variance showed significant (p <.05) reductions in chronic migraine symptoms in the four intervention groups. Compared with the sham (η² < 0.18) and other protocols (two = η² > 0.42; three = η² > 0.40; four = η² > 0.51), protocol one [l. anode at the right ventrolateral prefrontal cortices, cathode at the left dorsomedial and superior frontal gyrus-first montage; anode at the right primary motor area, cathode at the medial crosstalk of hemispheres-second montage] showed a larger effect size (η² > 0.59) in the present trial.

CONCLUSIONS

With the applied protocols of the present trial, tDCS can be used as an effective intervention for the prophylactic and therapeutic treatment of chronic migraine. However, while the second protocol was the least effective, the first was the most effective at reducing migraine symptoms.

SIGNIFICANCE

To our knowledge, the present trial is the first study to cover the gaps of the earlier ones, including the parameters like the site of stimulation, electrode range distribution and field intensity, number of sessions, session design, and sample size.

Advances in Non-Invasive Neuromodulation

PURPOSE OF REVIEW

Pain medicine is rapidly expanding. The gap in treatment for patients with chronic pain in between traditional conservative therapy and major invasive surgery is closing. Neuromodulation is one therapeutic area that has continued to show promise for treatment of chronic pain. Our aim is to review updates in non-invasive neuromodulation (NIN) techniques as an adjunct for various chronic pain conditions.

RECENT FINDINGS

Overall, the literature suggests that NIN techniques such as tCDS, TMS, TENS, tVNS, and HIFUS/LIFUS have utility in treating various types of chronic pain and have a promising future. There is a better understanding of the mechanistic basis for pain relief from NIN, as well as refinement in technology improving NIN therapy success. Future studies will need to focus on continuing to refine protocols for optimal benefit from NIN as well as implementing larger RCTs to improve the quality of data being generated in the field.

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.

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.

A Systematic Review and Meta-Analysis on the Efficacy of Repeated Transcranial Direct Current Stimulation for Migraine

Purpose

Transcranial direct current stimulation (tDCS) may have therapeutic potential in the management of migraine. However, studies to date have yielded conflicting results. We reviewed studies using repeated tDCS for longer than 4 weeks in migraine treatment, and performed meta-analysis on the efficacy of tDCS in migraine.

Methods

In this meta-analysis, we included the common outcome measurements reported across randomized controlled trials (RCTs). Subgroup analysis was performed at different post-treatment endpoints, and with different stimulation intensities and polarities.

Results

Five RCTs were included in the quantitative meta-analysis with a total of 104 migraine patients. We found a significant reduction of migraine pain intensity (MD: −1.44; CI: [−2.13, −0.76]) in active vs sham tDCS treated patients. Within active treatment groups, pain intensity and duration were significantly improved from baseline after tDCS treatment (intensity MD: −1.86; CI: [−3.30, −0.43]; duration MD: −4.42; CI: [−8.11, −0.74]) and during a follow-up period (intensity MD: −1.52; CI: [−1.84, −1.20]; duration MD: −1.94; CI: [−3.10, −0.77]). There was a significant reduction of pain intensity by both anodal (MD: −1.74; CI: [−2.80, −0.68]) and cathodal (MD: −1.49; CI: [−1.89, −1.09]) stimulation conditions.

Conclusion

tDCS treatment repeated over days for a period of 4 weeks or more is effective in reducing migraine pain intensity and duration of migraine episode. The benefit of tDCS can persist for at least 4 weeks after the completion of last tDCS session. Both anodal and cathodal stimulation are effective for reducing migraine pain intensity.

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.

Transcranial Direct Current Stimulation and Migraine-The Beginning of a Long Journey

Migraine, a benign yet disturbing condition, is one of the frequent neurological disorders, affecting up to 15-20% of the worldwide population [...].