Non-invasive Neuromodulation in Primary Headaches

The evolutionary meaning of migraine

INTRODUCTION

Migraine's astonishing prevalence and preserved genetic background contrast with the definition of a disease and the biological meaning of experiencing recurrent, severe headache attacks is still puzzling.

METHODS

To provide a comprehensive explanation of the migraine evolutionary meaning, we review (i) the putative role of the autonomic nervous system in migraine attacks, (ii) the inter-ictal autonomic, functional, and metabolic signature of migraine patients, (iii) the bio-behavioral perspective of pain, and (iv) the allostatic perception of migraine chronification.

RESULTS

Migraineurs have inter-ictal cortical hyperexcitability and metabolic dysfunction that predisposes to brain energetic imbalance. Multiple precipitating factors may lead to brain energy consumption over the migraine attack generation threshold. In response, the brain engenders adaptive, evolutionary conserved, autonomic-behavior responses through the antidromic activation of the trigeminovascular system. The sickness behavior and severe pain experienced during migraine attacks result in avoiding mental and physical activity, allowing brain energy restoration. Chronic exposure to stressors may result in an allostatic overload, leading to maladaptive chronic activation of these responses. In this bio-behavioral perspective, the chronification of migraine should be envisioned as a pathological process, whereas the migraine itself should not.

CONCLUSION

Migraine has an evolutionary (Darwinian) meaning.

Non-invasive neuromodulation in the acute treatment of migraine: a systematic review and meta-analysis of randomized controlled trials

OBJECTIVE

A systematic review and meta-analysis was performed to determine the efficacy of non-invasive neuromodulation modalities for the treatment of acute migraine.

BACKGROUND

Although pharmacological treatments are the gold standard for the management of acute migraine, some patients may require non-pharmacological treatment options. Non-invasive neuromodulation may provide an alternative, and techniques include transcranial magnetic stimulation (TMS), non-invasive vagal nerve stimulation (nVNS), non-painful remote electrical stimulation (NRES), and external trigeminal nerve stimulation (e-TNS).

METHODS

This systematic review and meta-analysis was performed following PRISMA guidelines. We searched PUBMED, EMBASE, ClinicalTrials.gov, Cochrane Center Register of Controlled Trials, and LILACS databases. We included randomized controlled clinical trials studying patients with migraine treated with any form of non-invasive neuromodulation. Primary outcome was pain freedom within 2 h post-treatment. Secondary outcomes were pain relief within 2-h post-treatment and sustained pain freedom and sustained pain relief 48 h post-treatment.

RESULTS

Pooled analysis demonstrated a significant effect of non-invasive neuromodulation on pain-free rates within 2 h (RR, 1.66; 95% CI, 1.35 to 2.05; P < 0.00001) and pain relief rates within 2 h (RR, 1.52; 95% CI, 1.13 to 2.05; P = 0.005) post-treatment. Non-invasive neuromodulation had no significant effect on sustained pain freedom at 48 h (RR, 1.56; 95% CI, 0.68 to 3.59; P = 0.29) or sustained pain relief at 48 h (RR, 1.47; 95% CI, 0.57 to 3.77; P = 0.43) after administration.

CONCLUSION

Neuromodulation has demonstrated some efficacy in acute migraine management and may be considered in the treatment paradigm of acute migraine in patients with contraindications to pharmacological therapies.

Cortical Mechanisms of Single-Pulse Transcranial Magnetic Stimulation in Migraine

Single-pulse transcranial magnetic stimulation (sTMS) of the occipital cortex is an effective migraine treatment. However, its mechanism of action and cortical effects of sTMS in migraine are yet to be elucidated. Using calcium imaging and GCaMP-expressing mice, sTMS did not depolarise neurons and had no effect on vascular tone. Pre-treatment with sTMS, however, significantly affected some characteristics of the cortical spreading depression (CSD) wave, the correlate of migraine aura. sTMS inhibited spontaneous neuronal firing in the visual cortex in a dose-dependent manner and attenuated L-glutamate-evoked firing, but not in the presence of GABAA/B antagonists. In the CSD model, sTMS increased the CSD electrical threshold, but not in the presence of GABAA/B antagonists. We first report here that sTMS at intensities similar to those used in the treatment of migraine, unlike traditional sTMS applied in other neurological fields, does not excite cortical neurons but it reduces spontaneous cortical neuronal activity and suppresses the migraine aura biological substrate, potentially by interacting with GABAergic circuits.

Remote Electrical Neuromodulation for the Acute Treatment of Migraine in Patients with Chronic Migraine: An Open-Label Pilot Study

INTRODUCTION

Remote electrical neuromodulation (REN) is a novel acute treatment of migraine. Upper arm peripheral nerves are stimulated to induce conditioned pain modulation (CPM)-an endogenous analgesic mechanism in which conditioning stimulation inhibits pain in remote body regions. The REN device (Nerivio^®, Theranica Bio-Electronics LTD., Israel) is FDA-authorized for acute treatment of migraine in adults who do not have chronic migraine. The current study assessed the consistency of response over multiple migraine attacks in people with chronic migraine who are typically characterized with severe pain intensity, high disability, and less robust response to triptans.

METHODS

This was an open-label, single-arm, dual-center study conducted on adults with chronic migraine. Participants underwent a 4-week treatment phase in which they treated their migraine headaches with the device for 45 min within 1 h of attack onset. Pain levels were recorded at baseline, 2 h, and 24 h post-treatment. Efficacy outcomes (pain relief and pain-free responses at 2 h, sustained pain relief and sustained pain-free responses at 24 h) focused on intra-individual consistency of response across multiple attacks, which was defined as response in at least 50% of the treatments.

RESULTS

Forty-two participants were enrolled, and 38 participants were evaluable for analyses; 73.7% (28/38) achieved pain relief at 2 h, 26.3% (10/38) were pain-free at 2 h, 84.4% (27/32) had sustained pain relief response at 24 h and 45.0% (9/20) had sustained pain relief response at 24 h in at least 50% of their treated attacks. The effects of REN on associated symptoms and improvement in function were also consistent. The incidence of device-related adverse events was low (1.8%).

CONCLUSIONS

REN used for a series of migraine attacks was effective and well tolerated across attacks. REN may offer a safe and effective non-pharmacological alternative for acute treatment in patients with chronic migraine.

TRIAL REGISTRATION

ClinicalTrials.gov identifier, NCT04161807. Retrospectively registered on November 13, 2019.

Transcutaneous Supraorbital Stimulation as a Preventive Treatment for Chronic Migraine: A Prospective, Open-Label Study

BACKGROUND AND OBJECTIVE

Successful preventive treatment in chronic migraine (CM) remains an unmet need in some cases, and new therapeutic strategies are emerging. We aimed to test the effect of noninvasive, transcutaneous supraorbital nerve stimulation (tSNS) in a group of patients with CM.

PATIENTS AND METHODS

This was an open label, quasi-experimental design. Twenty-five CM patients were recruited from two hospital headache clinics. After a one-month baseline period, monthly visits were scheduled during three months. Headache occurrence, its intensity, and symptomatic medication intake were recorded through a diary kept by each patient. Both a per-protocol analysis and an intention-to-treat analysis were performed for the main outcome measures.

RESULTS

Twenty-one and 24 patients were included in the per-protocol and the intention-to-treat analyses, respectively. In the per-protocol analysis, a significant four-day decrease in the mean monthly days with moderate or severe headache was observed from baseline to the end of the study (t test, P = 0.0163), and there was a nonsignificant reduction of 2.95 in the mean monthly total headache days. In the intention-to-treat analysis, a nonsignificant 3.37 reduction in the mean monthly days with moderate or severe headache was observed for the same period, and there was a significant 2.75 reduction in the mean monthly days with any headache (t test, P = 0.016).

CONCLUSIONS

tSNS could hold preventive properties in the treatment of CM, but the effect may be either mild or controversial. Double blind, sham-controlled studies are essential to confirm these findings and to outline their clinical relevance in the CM therapeutic scenario.

Visualizing the trigeminovagal complex in the human medulla by combining ex-vivo ultra-high resolution structural MRI and polarized light imaging microscopy

A trigeminovagal complex, as described in some animals, could help to explain the effect of vagus nerve stimulation as a treatment for headache disorders. However, the existence of a trigeminovagal complex in humans remains unclear. This study, therefore investigated the existence of the trigeminovagal complex in humans. One post-mortem human brainstem was scanned at 11.7T to obtain structural (T1-weighted) and diffusion magnetic resonance images ((d)MR images). Post-processing of dMRI data provided track density imaging (TDI) maps to investigate white matter at a smaller resolution than the imaging resolution. To evaluate the reconstructed tracts, the MR-scanned brainstem and three additional brainstems were sectioned for polarized light imaging (PLI) microscopy. T1-weighted images showed hyperintense vagus medullar striae, coursing towards the dorsomedial aspect of the medulla. dMRI-, TDI- and PLI-images showed these striae to intersect the trigeminal spinal tract (sp5) in the lateral medulla. In addition, PLI images showed that a minority of vagus fibers separated from the vagus trajectory and joined the trigeminal spinal nucleus (Sp5) and the sp5. The course of the vagus tract in the rostral medulla was demonstrated in this study. This study shows that the trigeminal- and vagus systems interconnect anatomically at the level of the rostral medulla where the vagus fibers intersect with the Sp5 and sp5. Physiological and clinical utility of this newly identified interconnection is a topic for further research.

Preventive Therapy of Migraine

PURPOSE OF REVIEW

This article reviews the preventive therapy of migraine, including indications, strategies for use, and available treatments.

RECENT FINDINGS

Lifestyle modifications and migraine trigger avoidance are recommended as preventive measures for all individuals with migraine. The decision to recommend additional migraine preventive therapy should consider the frequency of migraine attacks and headaches, extent of migraine-associated disability, frequency of using acute migraine treatments and the responsiveness to such treatments, and patient preferences. Additional therapies include prescription medications, nutraceuticals, neurostimulation, and behavioral therapy. Considering evidence for efficacy and the risk of potential side effects and adverse events, treatments with the most favorable profiles include (in alphabetical order): amitriptyline, beta-blockers (several), biofeedback, candesartan, coenzyme Q10, cognitive-behavioral therapy, magnesium citrate, onabotulinumtoxinA (for chronic migraine only), relaxation therapy, riboflavin, and topiramate. In addition, erenumab, a calcitonin gene-related peptide (CGRP) receptor monoclonal antibody, received approval from the US Food and Drug Administration (FDA) for the prevention of migraine in May 2018.

SUMMARY

Successful migraine preventive therapy reduces the frequency and burden of attacks while causing limited side effects. Individual treatment recommendations are determined based upon evidence for efficacy, side effect and adverse event profiles, medication interactions, patient comorbidity, costs, and patient preferences. Patients must be counseled on reasonable expectations for their preventive therapy and the importance of adhering to the recommended treatment plan for a period of time that is sufficient to determine outcomes.

Headache in mitochondrial disorders

Headache is a prominent feature in mitochondrial disorders (MIDs) but no comprehensive overview is currently available. This review aims at summarising and discussing findings concerning type, frequency, pathogenesis, and treatment of headache in MIDs. The most frequent headache types in MIDs are migraine and migraine-like headache (MLH). MLH is classified as secondary headache. More rarely, tension-type headache, trigemino-autonomic headache, or different secondary headaches can be found. Migraine or MLH may manifest with or without aura. MLH is frequently associated with an ongoing or previous stroke-like episode (SLE) or a seizure but may also occur independently of other neurological features. MLH may be associated with prolonged aura or visual phenomena after headache. Except for MLH, treatment of headache in MIDs is not at variance from other causes of headache. Beyond the broadly accepted subtype-related headache treatment, diet, cofactors, vitamins, and antioxidants may provide a supplementary benefit. Midazolam, l-arginine, or l-citrulline may be beneficial for MLH. The pathogenesis of headache in MIDs largely remains unsolved. However, since migraine and MLH respond both to triptanes, a shared pathomechanism is likely. In conclusion, migraine and MLH are the prominent headache types in MIDs. MLH may or may not be associated with current or previous SLEs. MLH is pathophysiologically different from migraine and requires treatment at variance from that of migraine with aura.

Transcranial Magnetic Stimulation for Migraine Prevention in Adolescents: A Pilot Open-Label Study

OBJECTIVE

To assess the feasibility, tolerability, and patient acceptability of single-pulse transcranial magnetic stimulation (sTMS) for migraine prevention in adolescents in an open-label pilot study.

BACKGROUND

Migraine is common in adolescents and can be disabling. Well tolerated preventative therapies that are safe and effective are needed.

METHODS

This was an open-label prospective pilot feasibility study of sTMS for migraine prevention in adolescents aged 12-17 years. Participants used sTMS twice daily in a preventative fashion, as well as additional pulses as needed acutely. A 4-week baseline run-in period (weeks 1-4) was followed by a 12-week treatment period. Feasibility was the primary outcome. Secondary outcomes included tolerability and acceptability, as well as the change in headache days, number of moderate/severe headache days, days of acute medication use, and PedMIDAS (headache disability) scores between the run-in period (weeks 1-4) and the third month of treatment (weeks 13-16).

RESULTS

Twenty-one participants enrolled. Nineteen completed the baseline run-in, and 12 completed the study. Using sTMS proved feasible and acceptable with overall high compliance once treatment administration was streamlined. Initially, for preventive treatment, participants were asked to give 2 pulses, wait 15 minutes, then give 2 additional pulses twice daily. This 15-minute delay proved challenging for adolescents, particularly on school days, and therefore was dropped. Study completion rate went from 4/13 (31%) to 7/8 (88%) once this change was made, P = .024. On average, participants used the device preventively between 22 and 24 days over a 28-day block. There were no serious adverse events. Two participants reported mild discomfort with device use.

CONCLUSION

sTMS appears to be a feasible, well-tolerated, and acceptable nonpharmacologic preventive treatment for migraine in adolescents. In designing future trials of sTMS for migraine prevention in adolescents, streamlined treatment administration will be essential to minimize drop-out. Efficacy needs to be assessed in a larger trial.

A Short Review of the Non-invasive Transcutaneous Pericranial Electrical Stimulation Techniques and their Application in Headache

PURPOSE OF REVIEW

In this short review, the most common non-invasive neuromodulatory techniques will be described, along with their advantages and disadvantages and their application in headache. Available preventive treatments can be unhelpful or may have unpleasant side effects; moreover, the rate of response to preventive drugs does not exceed 50%, lower in chronic migraine; alternative options would be welcome. Though the concept of neuromodulation was originally developed with invasive methods, newer non-invasive techniques are appearing.

RECENT FINDINGS

The novel neuromodulatory techniques have been developed with encouraging results: compared with traditional pharmacotherapy, advantages of non-invasive neuromodulation include reduced incidence of adverse effects, improved adherence, and safety and ease of use. The results are encouraging for acute or preventive treatment of different kinds of headache. A variety of neuromodulatory approaches is expanding fastly and has opened new possibilities for treatment of patients suffering from many forms of headache, especially those who have failed traditional pharmacotherapy. The non-invasive treatments can be seen as supplementing traditional management in refractory patients. Current study results are encouraging but preliminary and larger and more rigorous trials are needed to clarify benefit and mode of action.