The role of left prefrontal transcranial magnetic stimulation in episodic migraine prophylaxis

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.

Efficacy and safety of high-frequency repetitive transcranial magnetic stimulation (rTMS) for migraine: a meta-analysis of randomized controlled trials

OBJECTIVE

To assess the efficacy and safety of high-frequency repetitive transcranial magnetic stimulation in the prevention or treatment of migraine by conducting a pooled analysis of relevant randomized controlled trials.

METHODS

The PubMed, Embase, Cochrane, OVID, SCOPUS, Web of Science, and clinicaltrials.gov databases were systematically searched for randomized controlled trials (RCTs) comparing high-frequency rTMS and sham stimulation for the prevention or treatment of migraine. A meta-analysis of relevant outcome measures was performed using RevMan 5.3 software.

RESULTS

Eight RCTs with a total of 384 patients were included. A total of 23 patients dropped out, and thus, 361 patients were ultimately included for analysis. The high-frequency rTMS group had a lower frequency of attacks than the sham group (MD = - 5.10; 95% CI: - 8.10, - 2.09; P = 0.0009). The rTMS group has less intense headaches than the sham group (SMD = - 0.74; 95% CI - 1.04, - 0.44; P < 0.00001). High-frequency rTMS improved patient disability (SMD = - 0.45; 95% CI - 0.75, - 0.16; P = 0.003). High-frequency rTMS led to no advantage in reducing the number of abortive medications (MD = - 1.10; 95% CI - 3.28, 1.08; P = 0.32), but it increased the occurrence of adverse events (RR = 1.69; 95% CI 1.09, 2.64; P = 0.02).

CONCLUSIONS

High-frequency rTMS reduces the frequency of attacks and headache intensity in migraine patients and improves the patient's disability, but it also increases adverse events.

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 repetitive transcranial magnetic stimulation on chronic migraine: A meta-analysis

Introduction

Migraine is a neurovascular disorder that affects the quality of life of more than 1 billion people worldwide. Repetitive transcranial magnetic stimulation (rTMS) is a neuromodulation tool that uses pulsed magnetic fields to modulate the cerebral cortex. This meta-analysis ascertained the therapeutic or preventive effect of rTMS on chronic migraine.

Methods

We performed a database search of PubMed, Web of Science, Embase, and the Cochrane Library from January 2004 to December 2021. Eligible studies included randomized controlled studies of the analgesic effects of rTMS in patients with chronic migraine.

Results

Eight studies were included. Random effects analysis showed an effect size of -1.13 [95% confidence interval (CI): -1.69 to -0.58] on the frequency of migraine attacks, indicating that rTMS was more effective for decreasing migraine attacks than the sham rTMS.

Conclusions

The meta-analysis revealed that rTMS is an effective approach for reducing migraine attack when the dorsolateral prefrontal cortex was stimulated. However, rTMS may not be suggested as a method to reduce the pain level.

Systematic review registration

http://www.crd.york.ac.uk/PROSPERO/, identifier: CRD42021228344.

Systematic Review and Meta-Analysis of High-Frequency rTMS over the Dorsolateral Prefrontal Cortex .on Chronic Pain and Chronic-Pain-Accompanied Depression

The effect of high-frequency (HF) repetitive transcranial magnetic stimulation (rTMS) on the dorsolateral prefrontal cortex (DLPFC) can relieve chronic pain and accompanying depressive symptoms. However, in recent years, some high-quality studies have challenged this view. Therefore, it is necessary to update the data and analyze the effects of HF rTMS on the DLPFC on chronic pain and accompanying depression. We performed a systematic review and meta-analysis to evaluate the effect of HF rTMS on the DLPFC on chronic pain and accompanying depression. We searched PubMed, Medline, Web of Science, and Cochrane through September 2021. The search strings searched were : "pain" AND ("TMS" OR "transcranial magnetic stimulation") AND "prefrontal cortex". The inclusion criteria according to PICOS was as follows: P, patient with chronic pain; I, HF (≥5 Hz) rTMS on the DLPFC; C, included a sham treatment condition; O, pain indicators; S, pre-/poststudies, crossover, or parallel-group. We extracted the pain and accompanying depression evaluation indicators. The short-term analgesic effect of HF rTMS over the left DLPFC is not significant (WMD = 0.34, 95% CI: [-1.60, 2.28]) but has a significant mid-term and long-term analgesic effect on chronic pain (WMD = -0.50, 95% CI: [-0.99, -0.01]; WMD = -1.10, 95% CI: [-2.00, -0.19], respectively). HF rTMS over the DLPFC can effectively alleviate the depressive symptoms of patients with chronic pain (WMD = -0.83, 95% CI: [-3.01, 1.36]). Thus, HF rTMS on the left DLPFC can relieve chronic pain and accompanying depressive symptoms.

Repetitive Transcranial Magnetic Stimulation for Neuropathic Pain on the Non-Motor Cortex: An Evidence Mapping of Systematic Reviews

OBJECTIVE

This study was aimed to summarize and analyze the quality of the available evidence in systematic reviews (SRs) of repetitive transcranial magnetic stimulation (rTMS) on the non-motor cortex (non-M1) for neuropathic pain (NP) through an evidence mapping approach.

METHODS

We follow the Global Evidence Mapping (GEM) methodology. Searches were conducted in PubMed, EMBASE, Epistemonikos, and the Cochrane Library. The study type was restricted to SRs with or without meta-analysis. All literature published before January 23, 2021, were included. The methodological quality of the included SRs was assessed using A Measurement Tool to Assess Systematic Reviews (AMSTAR-2). Data were extracted according to a defined population-intervention-comparison-outcome (PICO) framework from primary studies that included SRs. The same PICO was categorized into PICOs according to interventions (stimulation target, frequency, number of sessions (short: 1-5 sessions, medium: 5-10 sessions, and long: >10 sessions)) and comparison (sham rTMS or other targets). The evidence mapping was presented in tables and a bubble plot.

RESULTS

A total of 23 SRs were included. According to the AMSTAR-2, 20 SRs scored "very low" in terms of methodological quality, 2 SRs scored "low," and 1 SR scored "high." A total of 17 PICOs were extracted. The dorsolateral prefrontal cortex (DLPFC) is the most studied of the non-motor cortex targets. PICOs of DLPFC, premotor cortex (PMC), frontal cortex, and secondary somatosensory cortex (S2) were mainly categorized with a "potentially better" conclusion. High-frequency (5-20 Hz) rTMS of non-M1 usually lead to "potentially better" conclusions.

CONCLUSIONS

DLPFC, PMC, frontal cortex, and S2 seem to be promising new targets for rTMS treatment of certain NP. Evidence mapping is a useful and reliable methodology to identify and present the existing evidence gap that more research efforts are necessary in order to highlight the optimal stimulation protocols for non-M1 targets and standardize parameters to fill the evidence gaps of rTMS. Further investigation is advised to improve the methodological quality and the reporting process of SRs.

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.

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.