Neurostimulation for Treatment of Migraine and Cluster Headache

Chronic Stress and Headaches: The Role of the HPA Axis and Autonomic Nervous System

Chronic stress significantly influences the pathogenesis of headache disorders, affecting millions worldwide. This review explores the intricate relationship between stress and headaches, focusing on the dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). Persistent stress could lead to neuroinflammation, increased pain sensitivity, and vascular changes that could contribute to headache development and progression. The bidirectional nature of this relationship creates a vicious cycle, with recurrent headaches becoming a source of additional stress. Dysregulation of the HPA axis and ANS imbalance could amplify susceptibility to headaches, intensifying their frequency and severity. While pharmacological interventions remain common, non-pharmacological approaches targeting stress reduction, such as cognitive-behavioral therapy, biofeedback, and relaxation techniques, offer promising avenues for comprehensive headache management. By addressing the underlying stress-related mechanisms, these approaches provide a sustainable strategy to reduce headache frequency and improve patients' quality of life.

Harnessing Brain Plasticity: The Therapeutic Power of Repetitive Transcranial Magnetic Stimulation (rTMS) and Theta Burst Stimulation (TBS) in Neurotransmitter Modulation, Receptor Dynamics, and Neuroimaging for Neurological Innovations

Transcranial magnetic stimulation (TMS) methods have become exciting techniques for altering brain activity and improving synaptic plasticity, earning recognition as valuable non-medicine treatments for a wide range of neurological disorders. Among these methods, repetitive TMS (rTMS) and theta-burst stimulation (TBS) show significant promise in improving outcomes for adults with complex neurological and neurodegenerative conditions, such as Alzheimer's disease, stroke, Parkinson's disease, etc. However, optimizing their effects remains a challenge due to variability in how patients respond and a limited understanding of how these techniques interact with crucial neurotransmitter systems. This narrative review explores the mechanisms of rTMS and TBS, which enhance neuroplasticity and functional improvement. We specifically focus on their effects on GABAergic and glutamatergic pathways and how they interact with key receptors like N-Methyl-D-Aspartate (NMDA) and AMPA receptors, which play essential roles in processes like long-term potentiation (LTP) and long-term depression (LTD). Additionally, we investigate how rTMS and TBS impact neuroplasticity and functional connectivity, particularly concerning brain-derived neurotrophic factor (BDNF) and tropomyosin-related kinase receptor type B (TrkB). Here, we highlight the significant potential of this research to expand our understanding of neuroplasticity and better treatment outcomes for patients. Through clarifying the neurobiology mechanisms behind rTMS and TBS with neuroimaging findings, we aim to develop more effective, personalized treatment plans that effectively address the challenges posed by neurological disorders and ultimately enhance the quality of neurorehabilitation services and provide future directions for patients' care.

Wireless control of nerve growth using bipolar electrodes: a new paradigm in electrostimulation

Electrical activity underpins all life, but is most familiar in the nervous system, where long range electrical signalling is essential for function. When this is lost (e.g., traumatic injury) or it becomes inefficient (e.g., demyelination), the use of external fields can compensate for at least some functional deficits. However, its potential to also promote biological repair at the cell level is underplayed despite abundant in vitro evidence for control of neuron growth. This perspective article considers specifically the emerging possibility of achieving cell growth through the interaction of external electric fields using conducting materials as unwired bipolar electrodes, and without intending stimulation of neuron electrical activity to be the primary consequence. The use of a wireless method to create electrical interactions represents a paradigm shift and may allow new applications in vivo where physical wiring is not possible. Within that scheme of thought an evaluation of specific materials and their dynamic responses as bipolar unwired electrodes is summarized and correlated with changes in dynamic nerve growth during stimulation, suggesting possible future schemes to achieve neural growth using bipolar unwired electrodes with specific characteristics. This strategy emphasizes how nerve growth can be encouraged at injury sites wirelessly to induce repair, as opposed to implanting devices that may substitute the neural signals.

Individualized brain mapping for navigated neuromodulation

ABSTRACT

The brain is a complex organ that requires precise mapping to understand its structure and function. Brain atlases provide a powerful tool for studying brain circuits, discovering biological markers for early diagnosis, and developing personalized treatments for neuropsychiatric disorders. Neuromodulation techniques, such as transcranial magnetic stimulation and deep brain stimulation, have revolutionized clinical therapies for neuropsychiatric disorders. However, the lack of fine-scale brain atlases limits the precision and effectiveness of these techniques. Advances in neuroimaging and machine learning techniques have led to the emergence of stereotactic-assisted neurosurgery and navigation systems. Still, the individual variability among patients and the diversity of brain diseases make it necessary to develop personalized solutions. The article provides an overview of recent advances in individualized brain mapping and navigated neuromodulation and discusses the methodological profiles, advantages, disadvantages, and future trends of these techniques. The article concludes by posing open questions about the future development of individualized brain mapping and navigated neuromodulation.

From CGRP to PACAP, VIP, and Beyond: Unraveling the Next Chapters in Migraine Treatment

Migraine is a neurovascular disorder that can be debilitating for individuals and society. Current research focuses on finding effective analgesics and management strategies for migraines by targeting specific receptors and neuropeptides. Nonetheless, newly approved calcitonin gene-related peptide (CGRP) monoclonal antibodies (mAbs) have a 50% responder rate ranging from 27 to 71.0%, whereas CGRP receptor inhibitors have a 50% responder rate ranging from 56 to 71%. To address the need for novel therapeutic targets, researchers are exploring the potential of another secretin family peptide, pituitary adenylate cyclase-activating polypeptide (PACAP), as a ground-breaking treatment avenue for migraine. Preclinical models have revealed how PACAP affects the trigeminal system, which is implicated in headache disorders. Clinical studies have demonstrated the significance of PACAP in migraine pathophysiology; however, a few clinical trials remain inconclusive: the pituitary adenylate cyclase-activating peptide 1 receptor mAb, AMG 301 showed no benefit for migraine prevention, while the PACAP ligand mAb, Lu AG09222 significantly reduced the number of monthly migraine days over placebo in a phase 2 clinical trial. Meanwhile, another secretin family peptide vasoactive intestinal peptide (VIP) is gaining interest as a potential new target. In light of recent advances in PACAP research, we emphasize the potential of PACAP as a promising target for migraine treatment, highlighting the significance of exploring PACAP as a member of the antimigraine armamentarium, especially for patients who do not respond to or contraindicated to anti-CGRP therapies. By updating our knowledge of PACAP and its unique contribution to migraine pathophysiology, we can pave the way for reinforcing PACAP and other secretin peptides, including VIP, as a novel treatment option for migraines.

Frequency-specific modulation of oscillatory activity in the rat auditory cortex by vagus nerve stimulation

BACKGROUND

We previously found that vagus nerve stimulation (VNS) strengthened stimulus-evoked activity in the superficial layer of the sensory cortex but not in the deep layer, suggesting that VNS altered the balance between the feedforward (FF) and feedback (FB) pathways. Band-specific oscillatory activities in the cortex could serve as an index of the FF-FB balance, but whether VNS affects cortical oscillations along sensory pathways through neuromodulators remains unclear.

HYPOTHESIS

VNS modulates the FF-FB balance through the cholinergic and noradrenergic systems, which modulate stimulus gain in the cortex.

METHODS

We investigated the effects of VNS using electrocorticography in the auditory cortex of 34 Wistar rats under general anesthesia while presenting click stimuli. In the time-frequency analyses, the putative modulation of the FF and FB pathways was estimated using high- and low-frequency power. We assessed, using analysis of variance, how VNS modulates auditory-evoked activities and how the modulation changes with cholinergic and noradrenergic antagonists.

RESULTS

VNS increased auditory cortical evoked potentials, consistent with results of our previous work. Furthermore, VNS increased auditory-evoked gamma and beta powers and decreased theta power. Local administration of cholinergic antagonists in the auditory cortex selectively disrupted the VNS-induced increase in gamma and beta power, while noradrenergic antagonists disrupted the decrease in theta power.

CONCLUSIONS

VNS might strengthen the FF pathway through the cholinergic system and attenuate the FB pathway through the noradrenergic system in the auditory cortex. Cortical gain modulation through the VNS-induced neuromodulatory system provides new mechanistic insights into the effect of VNS on auditory processing.

Non-Invasive Neuromodulation Methods to Alleviate Symptoms of Huntington's Disease: A Systematic Review of the Literature

Huntington's disease (HD) is a progressive and debilitating neurodegenerative disease. There is growing evidence for non-invasive neuromodulation tools as therapeutic strategies in neurodegenerative diseases. This systematic review aims to investigate the effectiveness of noninvasive neuromodulation in HD-associated motor, cognitive, and behavioral symptoms. A comprehensive literature search was conducted in Ovid MEDLINE, Cochrane Central Register of Clinical Trials, Embase, and PsycINFO from inception to 13 July 2021. Case reports, case series, and clinical trials were included while screening/diagnostic tests involving non-invasive neuromodulation, review papers, experimental studies on animal models, other systematic reviews, and meta-analyses were excluded. We have identified 19 studies in the literature investigating the use of ECT, TMS, and tDCS in the treatment of HD. Quality assessments were performed using Joanna Briggs Institute's (JBI's) critical appraisal tools. Eighteen studies showed improvement of HD symptoms, but the results were very heterogeneous considering different intervention techniques and protocols, and domains of symptoms. The most noticeable improvement involved depression and psychosis after ECT protocols. The impact on cognitive and motor symptoms is more controversial. Further investigations are required to determine the therapeutic role of distinct neuromodulation techniques for HD-related symptoms.

Effect of group-based vs individualized stimulation site selection on reliability of network-targeted TMS

BACKGROUND

Transcranial magnetic stimulation (TMS) is a widely used technique for the noninvasive assessment and manipulation of brain activity and behavior. Although extensively used for research and clinical purposes, recent studies have questioned the reliability of TMS findings because of the high inter-individual variability that has been observed.

OBJECTIVE

In this study, we compared the efficacy and reliability of different targeting scenarios on the TMS-evoked response.

METHODS

24 subjects underwent a single pulse stimulation protocol over two parietal nodes belonging to the Dorsal Attention (DAN) and Default Mode (DMN) Networks respectively. Across visits, the stimulated target for both networks was chosen either based on group-derived networks' maps or personalized network topography based on individual anatomy and functional profile. All stimulation visits were conducted twice, one month apart, during concomitant electroencephalography recording.

RESULTS

At the network level, we did not observe significant differences in the TMS-evoked response between targeting conditions. However, reliable patterns of activity were observed- for both networks tested- following the individualized targeting approach. When the same analyses were carried out at the electrode space level, evidence of reliable patterns was observed following the individualized stimulation of the DAN, but not of the DMN.

CONCLUSIONS

Our findings suggest that individualization of stimulation sites might ensure reliability of the evoked TMS-response across visits. Furthermore, individualized stimulation sites appear to be of foremost importance in highly variable, high order task-positive networks, such as the DAN.

Migraine and Neuromodulation: A Literature Review

Migraine is not only known to be one of the most common causes of a headache around the globe but is also the leading neurologic cause of disability worldwide. Migraine has significant social and economic effects. It not only hampers patients' quality of life but also hampers work, public conduct, and family life. Migraine is one of the leading causes of morbidity in the world, so effective management is critical. Currently, medical management is the mainstay remedial approach for migraine, but with time, non-pharmacological approaches, especially neuromodulation, are gaining popularity with a shred of solid backing evidence. Neuromodulation is the process in which specific devices are used to excite the central nervous system or peripheral nervous system with electric or magnetic, or any other form of energy to regulate the abnormal behavior of neural pathways that have occurred due to the disease process. Neuromodulation devices as approved by Food and Drug Administration include non-invasive Vagus nerve stimulators, single-pulse transcranial magnetic stimulators, and transcutaneous supraorbital neurostimulators. The purpose of this study is to summarize the information about the advances relating to neuromodulation concerning managing and preventing migraine. This Narrative review article is prepared after analyzing various research papers and publications on PubMed and Google Scholar. This article holds brief information on understanding neuromodulation, its mechanism, its implication in managing migraine, and its different modalities with their mechanism of action and contraindications. These neuromodulation techniques can certainly be used to deal with acute migraine attacks and inhibit their progression to chronic illness. Research is required on the application of neuromodulation in the early diagnosis of migraine, which is what we still lack as a whole medical fraternity.

Maximizing brain networks engagement via individualized connectome-wide target search

BACKGROUND

In recent years, the possibility to noninvasively interact with the human brain has led to unprecedented diagnostic and therapeutic opportunities. However, the vast majority of approved interventions and approaches still rely on anatomical landmarks and rarely on the individual structure of networks in the brain, drastically reducing the potential efficacy of neuromodulation.

OBJECTIVE

Here we implemented a target search algorithm leveraging on mathematical tools from Network Control Theory (NCT) and whole brain connectomics analysis. By means of computational simulations, we aimed to identify the optimal stimulation target(s)- at the individual brain level- capable of reaching maximal engagement of the stimulated networks' nodes.

RESULTS

At the model level, in silico predictions suggest that stimulation of NCT-derived cerebral sites might induce significantly higher network engagement, compared to traditionally employed neuromodulation sites, demonstrating NCT to be a useful tool in guiding brain stimulation. Indeed, NCT allows us to computationally model different stimulation scenarios tailored on the individual structural connectivity profiles and initial brain states.

CONCLUSIONS

The use of NCT to computationally predict TMS pulse propagation suggests that individualized targeting is crucial for more successful network engagement. Future studies will be needed to verify such prediction in real stimulation scenarios.

Effectiveness of High-Frequency Repetitive Transcranial Magnetic Stimulation in Migraine: A Systematic Review and Meta-analysis

OBJECTIVE

The aim of the study was to evaluate the effectiveness of repetitive transcranial magnetic stimulation in migraine measured by decrease in pain severity or attack frequency.

METHODS

A search at the Cochrane Controlled Trials Register (CENTRAL), MEDLINE (via PubMed), Embase, CINAHL, Web of Science, and Scopus. The risk of systematic bias was rated by using the Cochrane domain-based quality assessment tool. A random-effects model was used.

RESULTS

Of 434 identified records, 8 randomized control studies were included in the meta-synthesis. All have used a high-frequency repetitive transcranial magnetic stimulation targeting the left dorsolateral prefrontal cortex. The risk of systematic bias was low. The difference between repetitive transcranial magnetic stimulation and control groups in frequency of migraine days per month was 8.1 (95% confidence interval = 4.8 - 11.4) days in favor of repetitive transcranial magnetic stimulation. Respectively, for intensity of migraine pain (scaled from 0 to 100), this difference was 13.6 (95% confidence interval = 5.3 - 21.8) points in favor of repetitive transcranial magnetic stimulation. The heterogeneity was substantial with I2 = 86%.

CONCLUSIONS

In chronic migraine, repetitive transcranial magnetic stimulation seems to have positive effects on both migraine pain severity and attack frequency compared with sham stimulation. Although the effect on pain intensity was probably clinically insignificant, repetitive transcranial magnetic stimulation reduced pain frequency by 8 days per month on average.

fMRI Findings in Cortical Brain Networks Interactions in Migraine Following Repetitive Transcranial Magnetic Stimulation

Background

Repetitive transcranial magnetic stimulation (rTMS) is one of the high-potential non-pharmacological methods for migraine treatment. The purpose of this study is to define the neuroimaging markers associated with rTMS therapy in patients with migraine based on data from functional MRI (fMRI).

Materials and Methods

A total of 19 patients with episodic migraine without aura underwent a 5-day course of rTMS of the fronto-temporo-parietal junction bilaterally, at 10 Hz frequency and 60% of motor threshold response of 900 pulses. Resting-state functional MRI (1.5 T) and a battery of tests were carried out for each patient to clarify their diagnosis, qualitative and quantitative characteristics of pain, and associated affective symptoms. Changes in functional connectivity (FC) in the brain's neural networks before and after the treatment were identified through independent components analysis.

Results

Over the course of therapy, we observed an increase in FC of the default mode network within it, with pain system components and with structures of the visual network. We also noted a decrease in FC of the salience network with sensorimotor and visual networks, as well as an increase in FC of the visual network. Besides, we identified 5 patients who did not have a positive response to one rTMS course after the first week of treatment according to the clinical scales results, presumably because of an increasing trend of depressive symptoms and neuroimaging criteria for depressive disorder.

Conclusions

Our results show that a 5-day course of rTMS significantly alters the connectivity of brain networks associated with pain and antinociceptive brain systems in about 70% of cases, which may shed light on the neural mechanisms underlying migraine treatment with rTMS.

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).

New Era of Electroceuticals: Clinically Driven Smart Implantable Electronic Devices Moving towards Precision Therapy

In the name of electroceuticals, bioelectronic devices have transformed and become essential for dealing with all physiological responses. This significant advancement is attributable to its interdisciplinary nature from engineering and sciences and also the progress in micro and nanotechnologies. Undoubtedly, in the future, bioelectronics would lead in such a way that diagnosing and treating patients' diseases is more efficient. In this context, we have reviewed the current advancement of implantable medical electronics (electroceuticals) with their immense potential advantages. Specifically, the article discusses pacemakers, neural stimulation, artificial retinae, and vagus nerve stimulation, their micro/nanoscale features, and material aspects as value addition. Over the past years, most researchers have only focused on the electroceuticals metamorphically transforming from a concept to a device stage to positively impact the therapeutic outcomes. Herein, the article discusses the smart implants' development challenges and opportunities, electromagnetic field effects, and their potential consequences, which will be useful for developing a reliable and qualified smart electroceutical implant for targeted clinical use. Finally, this review article highlights the importance of wirelessly supplying the necessary power and wirelessly triggering functional electronic circuits with ultra-low power consumption and multi-functional advantages such as monitoring and treating the disease in real-time.

Determination of Current Flow Induced by Transcutaneous Electrical Nerve Stimulation for the Treatment of Migraine: Potential for Optimization

Introduction: Transcutaneous electrical nerve stimulation (TENS) for migraine involves the application of pulsatile stimulation through electrodes placed on the forehead to target the underlying trigeminal nerves. It is a simple, safe modality and has secured clinical approval in several markets including the European Union and the United States. Despite nearing almost 7 years of use (postclinical approval), the exact mechanism of action is not fully known. Guided by the need to stimulate the trigeminal nerves bilaterally, electrode dimensions are simply required to extend enough to cover the underlying nerves. The goal of this study is to examine induced current flow [magnitude and spatial distribution of electric field (EF)] and another driver of stimulation [activating function (AF)] due to TENS therapy for migraine for the first time. We further consider the effect of changing the electrode dimension and shape and propose a design modification to deliver optimal flow. Methods: We developed the first ultra-high-resolution finite element (FE) model of TENS for migraine incorporating the target supratrochlear (ST) and the supraorbital (SO) nerves. We first simulated the clinically approved V-shaped geometry. We then considered three additional designs: extended V-shaped, idealized pill-shaped, and finally an extended V-shaped but with greater contact spacing (extended V-shaped +CS). Results: Our findings revealed that the clinically approved electrode design delivered substantially higher mean current flow to the ST nerve in comparison with the SO nerves (Medial: 53% and Lateral: 194%). Consideration of an extended design (~10 mm longer and ~ 4 mm shorter) and a pill-like design had negligible impact on the induced current flow pattern. The extended V-shaped +CS montage delivered relatively comparable current flow to each of the three target nerves. The EF induced in the ST nerve was 49 and 141% higher in the Medial and Lateral SO nerve, respectively. When considering maximum induced values, the delivery of comparable stimulation was further apparent. Given the existing electrode design's established efficacy, our results imply that preferential targeting of the ST nerve is related to the mechanism of action. Additionally, if comparable targeting of all three nerves continues to hold promise, the extended V-shaped +CS montage presents an optimized configuration to explore in clinical studies.

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.

Migraine in Multiple Sclerosis Patients Affects Functional Connectivity of the Brain Circuitry Involved in Pain Processing

Migraine is particularly common in patients with multiple sclerosis (MS) and has been linked to the dysfunction of the brain circuitry modulating the peripheral nociceptive stimuli. Using MRI, we explored whether changes in the resting state-functional connectivity (RS-FC) may characterize the occurrence of migraine in patients with MS. The RS-FC characteristics in concerned brain regions were explored in 20 MS patients with migraine (MS+M) during the interictal phase, and compared with 19 MS patients without migraine (MS-M), which served as a control group. Functional differences were correlated to the frequency and severity of previous migraine attacks, and with the resulting impact on daily activities. In MS+M, the loss of periaqueductal gray matter (PAG) positive connectivity with the default mode network and the left posterior cranial pons was associated with an increase of migraine attacks frequency. In contrast, the loss of PAG negative connectivity with sensorimotor and visual network was linked to migraine symptom severity and related daily activities impact. Finally, a PAG negative connection was established with the prefrontal executive control network. Migraine in MS+M patients and its impact on daily activities, underlies RS-FC rearrangements between brain regions involved in pain perception and modulation.

Systematic review of the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion for the treatment of refractory chronic cluster headache

INTRODUCTION

This study aimed to assess the safety and effectiveness of peripheral neurostimulation of the sphenopalatine ganglion (SPG) in the treatment of refractory chronic cluster headache.

DEVELOPMENT

Various medical databases were used to perform a systematic review of the scientific literature. The search for articles continued until 31 October 2016, and included clinical trials, systematic reviews and/or meta-analyses, health technology assessment reports, and clinical practice guidelines that included measurements of efficiency/effectiveness or adverse effects associated with the treatment. The review excluded cohort studies, case-control studies, case series, literature reviews, letters to the editor, opinion pieces, editorials, and studies that had been duplicated or outdated by later publications from the same institution. Regarding effectiveness, we found that SPG stimulation had positive results for pain relief, attack frequency, medication use, and patients' quality of life. In the results regarding safety, we found a significant number of adverse events in the first 30 days following the intervention. Removal of the device was necessary in some patients. Little follow-up data, and no long-term data, is available.

CONCLUSIONS

These results are promising, despite the limited evidence available. We consider it essential for research to continue into the safety and efficacy of SPG stimulation for patients with refractory chronic cluster headache. In cases where this intervention may be indicated, treatment should be closely monitored.

Variability in cTBS Aftereffects Attributed to the Interaction of Stimulus Intensity With BDNF Val66Met Polymorphism

Objective: To evaluate whether a common polymorphism (Val66Met) in the gene for brain-derived neurotrophic factor (BDNF)-a gene thought to influence plasticity-contributes to inter-individual variability in responses to continuous theta-burst stimulation (cTBS), and explore whether variability in stimulation-induced plasticity among Val66Met carriers relates to differences in stimulation intensity (SI) used to probe plasticity. Methods: Motor evoked potentials (MEPs) were collected from 33 healthy individuals (11 Val66Met) prior to cTBS (baseline) and in 10 min intervals immediately following cTBS for a total of 30 min post-cTBS (0 min post-cTBS, 10 min post-cTBS, 20 min post cTBS, and 30 min post-cTBS) of the left primary motor cortex. Analyses assessed changes in cortical excitability as a function of BDNF (Val66Val vs. Val66Met) and SI. Results: For both BDNF groups, MEP-suppression from baseline to post-cTBS time points decreased as a function of increasing SI. However, the effect of SI on MEPs was more pronounced for Val66Met vs. Val66Val carriers, whereby individuals probed with higher vs. lower SIs resulted in paradoxical cTBS aftereffects (MEP-facilitation), which persisted at least 30 min post-cTBS administration. Conclusions: cTBS aftereffects among BDNF Met allele carriers are more variable depending on the SI used to probe cortical excitability when compared to homozygous Val allele carriers, which could, to some extent, account for the inconsistency of previously reported cTBS effects. Significance: These data provide insight into the sources of cTBS response variability, which can inform how best to stratify and optimize its use in investigational and clinical contexts.

Is Noninvasive Vagus Nerve Stimulation a Safe and Effective Alternative to Medication for Acute Migraine Control?

BACKGROUND

Noninvasive neuromodulation devices have been used for a variety of headache disorders, including cluster and migraine, since recently being cleared by the Federal Drug Administration. Although these devices have been touted as low-risk options for improved headache control, the data behind actual efficacy endpoints remain unclear.

OBJECTIVE

To critically assess current evidence regarding the efficacy of the noninvasive vagus nerve stimulator (nVNS) device for acute migraine management.

METHODS

The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario with a clinical question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom line conclusions.Participants included consultant and resident neurologists, a medical librarian, clinical epidemiologists, and a content expert in the field of headache.

RESULTS

A randomized, double-blind, sham-controlled clinical trial was selected for critical appraisal. In this trial, the primary endpoint (pain freedom at 120 min after use of nVNS for first acute migraine attack) was not met when compared with sham device (30.4% for nVNS vs. 19.7% for sham; P=0.067). However, there were statistically significant differences found for various secondary endpoints favoring nVNS, such as pain freedom rates at 30 and 60 minutes, pain relief at 120 minutes, and mean percentage pain score reduction rates at 60 and 120 minutes.

CONCLUSIONS

When comparing nVNS with sham, no statistically significant differences were found with regards to the primary endpoint of pain freedom at 120 minutes, although differences were found with various secondary endpoints and post hoc analysis. nVNS is likely a safe alternative to medications.

Pain localization in cluster headache patients: Onset, peak, and radiation

OBJECTIVE AND AIM

To describe differences in pain locations for onset, peak, and radiation aspects of cluster headache (CH) attacks.

METHODS AND MATERIALS

Data were collected for 23 months using a cross-sectional online survey composed of 117 questions on pain location, demographics, and clinical features. 5260 datapoints on 44 pain locations from 631 respondents were analyzed.

RESULTS

During the onset and peak of attacks, pain is concentrated periorbitally. Pain locations outside the periorbital region were reported more frequently for radiation than for onset and peak of attacks. Dorsal (occipital, neck, shoulder) pain was reported more frequently in connection with onset and radiation than during peak: onset (13%) versus peak (6%), p < 0.001, and radiation (22%) versus peak (6%), p < 0.001. There was no significant difference in dorsal pain frequencies for onset (13%) vs. radiation (22%), p = 0.552. Furthermore, the frequency with which individual pain locations were reported differed significantly for onset, peak, and radiation in CH.

CONCLUSIONS

Analysis of the pain location data shows specific frequencies and distributions of pain location for three aspects of CH attacks. The frequency with which individual pain points were reported differed significantly for onset, peak, and radiation. In general, dorsal pain points were reported more frequently for onset and radiation than for peak pain. Pain locations beyond the eye (extraorbital points) were more frequently reported in connection with radiating pain. Our findings could serve as a basis for future research, correlating CH pain patterns with the outcome of treatment approaches.

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.

Newly discovered neuron-to-glioma communication: new noninvasive therapeutic opportunities on the horizon?

The newly discovered functional integration of glioma cells into brain networks in mouse models provides groundbreaking insight into glioma aggressiveness and resistance to treatments, also suggesting novel potential therapeutic avenues and targets. In the context of such neuron-to-glioma communication, noninvasive brain modulation techniques traditionally applied to modulate neuronal function in neurological and psychiatric diseases (eg, increase/decrease cortical excitability and plasticity) could now be tested in patients with brain tumors to suppress glioma’s activity and its pathological crosstalk with healthy brain tissue.

Peripheral Neuromodulation for the Management of Headache

CONTEXT

Neuromodulation is an expanding field of study for headache treatment to reduce pain by targeting structures within the nervous system that are commonly involved in headache pathophysiology, such as the vagus nerve (VNS), occipital nerves, or sphenopalatine ganglion (SPG) for stimulation. Pharmaceutical medical therapies for abortive and prophylactic treatment, such as triptans, NSAIDs, beta-blockers, TCAs, and antiepileptics, are effective for some individuals, but the role that technology plays in investigating other therapeutic modalities is essential. Peripheral neuromodulation has gained popularity and FDA approval for use in treating certain headaches and migraine headache conditions, particularly in those who are refractory to treatment. Early trials found FDA approved neurostimulatory implant devices, including Cephaly and SpringTMS, improved patient-oriented outcomes with reductions in headaches per month (frequency) and severity.

EVIDENCE ACQUISITION

This was a narrative review. The sources for this review are as follows: Searching on PubMed, Google Scholar, Medline, and ScienceDirect from 1990 - 2019 using keywords: Peripheral Neuromodulation, Headache, vagus nerve, occipital nerves, sphenopalatine ganglion.

RESULTS

The first noninvasive neurostimulator device approved for migraine treatment was the Cefaly device, an external trigeminal nerve stimulation device (e-TNS) that transcutaneously excites the supratrochlear and supraorbital branches of the ophthalmic nerve. The second noninvasive neurostimulation device receiving FDA approval was the single-pulse transcranial magnetic stimulator, SpringTMS, positioned at the occiput to treat migraine with aura. GammaCore is a handheld transcutaneous vagal nerve stimulator applied directly to the neck at home by the patient for treatment of cluster headache (CH) and migraine. Several other devices are in development for the treatment of headaches and target headache evolution at different levels and inputs. The Scion device is a caloric vestibular stimulator (CVS) which interfaces with the user through a set of small cones resting in the ear canal on either side and held in place by modified over-ear headphones. The pulsante SPG Microstimulator is a patient-controlled device implanted in the patient's upper jaw via an hour-long oral procedure to target the sphenopalatine ganglion. The occipital nerve stimulator (ONS) is an invasive neuromodulation device for headache treatment that consists of an implanted pulse generator on the chest wall connected to a subcutaneous lead with 4 - 8 electrodes that is tunneled the occiput.

CONCLUSIONS

The aim of this review is to provide a comprehensive overview of the efficacy, preliminary outcomes, and limitations of neurostimulatory implants available for use in the US and those pending further development.

Outcomes of Occipital Nerve Stimulation for Craniofacial Pain Syndromes

OBJECTIVES

Occipital nerve regional stimulation (ONS) is reported to improve pain in several studies. We examined long-term pain and functional outcomes of ONS in an open-label prospective study.

METHODS

Patients with medically refractory and disabling craniofacial pain were prospectively selected for ONS. Primary outcome was a change in mean daily pain intensity on the numeric pain rating scale (NPRS) at 6 months. Secondary outcomes included changes in NPRS, Headache Impact Test-6 (HIT-6), Migraine Disability Assessment (MIDAS), Pain Disability Index (PDI), Center for Epidemiologic Studies Depression Scale - Revised (CESD-R), and Short Form-36 version 2 (SF36) at last follow-up.

RESULTS

Thirteen patients (mean age 49.7 ± 8.4) diagnosed with occipital neuralgia (6), hemicrania continua (2), persistent idiopathic facial pain (2), post-traumatic facial pain (1), cluster headache (1), and chronic migraine (1) were enrolled. Mean NPRS improved by 2.1 ± 2.1 at 6 months and 2.1 ± 1.9 at last follow-up (23.5 ± 18.1 months). HIT-6 decreased by 8.7 ± 8.8, MIDAS decreased by 61.3 ± 71.6, and PDI decreased by 17.9 ± 18. SF36 physical functioning, bodily pain, and social functioning improved by 16.4 ± 19.6, 18.0 ± 31.6, and 26.1 ± 37.3, respectively. Moderate to severe headache days (defined as ≥50% of baseline mean NPRS) were reduced by 8.9 ± 10.2 days per month with ONS.

CONCLUSION

ONS reduced the long-term NPRS and moderate-severe monthly headache days by 30% and improved functional outcomes and quality of life. A prospective registry for ONS would be helpful in accumulating a larger cohort with longer follow-up in order to improve the use of ONS.

Occipital Nerve Stimulation in Chronic Migraine: The Relationship Between Perceived Sensory Quality, Perceived Sensory Location, and Clinical Efficacy-A Prospective, Observational, Non-Interventional Study

Introduction

Occipital nerve stimulation (ONS) is used to treat therapy-resistant chronic migraine. Clinical use has resulted in a wide intraindividual and interindividual variation of clinical efficacy. The aim of this study was to analyze a potential relationship between sociodemographic variables, headache parameters, perceived sensory quality, perceived sensory location, as well as clinical efficacy.

Methods

Thirty-two subjects (21.9% male, mean age 45.77 years) suffering from chronic migraine refractory to other treatment and therefore treated with ONS were included in this study. We used a computer-based imaging method for mapping the ONS-induced perceived sensory location, the perceived spatial sensory field size, as well as the perceived sensory quality in a long-term course over 21 months in weekly time intervals. Additionally, the effect of ONS on the migraine headache was documented weekly by the participants using a verbal rating scale. Over the observation period, a total of 808 individual weekly data sets were recorded and a potential relationship between ONS-induced perceptions and headache parameters could be analyzed.

Results

We found that 48.9% of stimulation intervals were reported as effective by patients. Women displayed a significantly higher responder rate than men. The reported effectiveness did not differ depending on age, the average number of migraine days per month, the MIDAS score, or the duration of the migraine disorder prior to ONS treatment. Implantation with trial period led to significantly lower responder rates than without the trial period. The most frequently perceived sensory quality of “tingling” was found significantly more frequently in non-responders than in responders. Responders displayed significantly lower pleasantness scores for their reported perceptions than non-responders. Sensations that were spatially perceived above the line connecting the external acoustic meati with the external occipital protuberance (MOP line) led to patients reporting a positive clinical effect significantly more frequently than sensations spatially perceived below the MOP line. Spatially small fields of sensory perception were correlated with a higher responder rate than those covering broader areas.

Conclusions

The ONS-induced sensory location, the size of the spatial sensory field, as well as the sensory quality are significantly correlated with the reported clinical effectiveness. The results suggest that besides surgical technique, the individual and continuous programming of the stimulation parameters is clinically relevant in increasing the therapeutic effectiveness.

Neuromodulation in headache and craniofacial neuralgia: guidelines from the Spanish Society of Neurology and the Spanish Society of Neurosurgery

INTRODUCTION

Numerous invasive and non-invasive neuromodulation devices have been developed and applied to patients with headache and neuralgia in recent years. However, no updated review addresses their safety and efficacy, and no healthcare institution has issued specific recommendations on their use for these 2 conditions.

METHODS

Neurologists from the Spanish Society of Neurology's (SEN) Headache Study Group and neurosurgeons specialising in functional neurosurgery, selected by the Spanish Society of Neurosurgery (SENEC), performed a comprehensive review of articles on the MEDLINE database addressing the use of the technique in patients with headache and neuralgia.

RESULTS

We present an updated review and establish the first set of consensus recommendations of the SEN and SENC on the use of neuromodulation to treat headache and neuralgia, analysing the current levels of evidence on its effectiveness for each specific condition.

CONCLUSIONS

Current evidence supports the indication of neuromodulation techniques for patients with refractory headache and neuralgia (especially migraine, cluster headache, and trigeminal neuralgia) selected by neurologists and headache specialists, after pharmacological treatment options are exhausted. Furthermore, we recommend that invasive neuromodulation be debated by multidisciplinary committees, and that the procedure be performed by teams of neurosurgeons specialising in functional neurosurgery, with acceptable rates of morbidity and mortality.

A Head-to-Head Comparison of Percutaneous Mastoid Electrical Stimulator and Supraorbital Transcutaneous Stimulator in the Prevention of Migraine: A Prospective, Randomized Controlled Study

INTRODUCTION

This prospective, randomized, multicenter head-to-head outcome study was performed to compare the efficacy and safety of Percutaneous Mastoid Electrical Stimulator (PMES) and Supraorbital Transcutaneous Stimulator (STS) in migraine prevention.

METHODS

This was a prospective, randomized, head-to-head outcome study that involved three medical centers. After a one-month run-in, episodic patients with at least two migraine attacks/month were randomized to receive PMES daily for 45 min or STS daily for 20 min for three months. The primary outcomes were change in monthly migraine days and the 50% response rate.

RESULTS

A total of 90 patients were included in this study. We observed statistically significant reduction of migraine days in the third month treatment both in the PMES group and STS group. The difference between the two groups was not significant (60.5% vs. 53.8%, p = 0.88). Of note, 77.8% patients in the PMES group and 62.2% patients in the STS group had a ≥50% reduction of migraine days in the third month (p = 0.070). The change in monthly migraine days, monthly migraine attacks, severity of migraine days, accompanying symptoms during migraine and monthly acute anti-migraine drug intake were not significantly different between the two groups. The change of Headache Impact Test-6 (HIT-6) from run-in to the third-month treatment in the STS group was more remarkable than that in the PMES group (36.5% vs. 25.6%, p = 0.041). The occurrence of discomfort paresthesia was higher in the STS group (13.3% vs. 0%, p = 0.026).

CONCLUSION

PMES and STS treatment were both effective in migraine prevention. The safety and efficacy of PMES and STS were comparable.

Is accelerated, high-dose theta burst stimulation a panacea for treatment-resistant depression?

A recent study by Williams et al. (Williams NR, Sudheimer KD, Bentzley BS, Pannu J, Stimpson KH, Duvio D, Cherian K, Hawkins J, Scherrer KH, Vyssoki B, DeSouza D, Raj KS, Keller J, Schatzberg AF. Brain 141: e18, 2018) used accelerated, high-dose intermittent theta burst stimulation (iTBS) to treat highly treatment-resistant depression patients. Remarkably, most patients remitted, but the durability of therapeutic response was weak and all patients relapsed within 2 wk posttreatment. This mini-review examines the “fast on, fast off” effects of accelerated, high-dose iTBS for depression and suggests a new treatment that would combine the strengths of multiple extant iTBS protocols.

A systematic review of high-frequency transcranial magnetic stimulation on motor cortex areas as a migraine preventive treatment

Background:

The results of high-frequency repetitive transcranial magnetic stimulation (rTMS) over the dorsolateral prefrontal cortex for migraine have been inconsistent. However, high-frequency rTMS over the motor cortex is a treatment that may be effective in relieving symptoms of migraine with a low risk of side effects.

Methods:

A systematic review of high-frequency rTMS over the brain motor cortex areas in human participants was conducted to assess efficacy in treating migraine. Articles that were not looking at migraine patients, stimulation over the left motor cortex, or were not in English were excluded. Nine articles representing eight experiments using high-frequency rTMS over the motor cortex areas for migraine in human participants were extracted from the databases of PubMed, PsycINFO, MedLine, CINAHL, and BioMed Central.

Results:

Two-hundred and seven of 213 patients completed treatment throughout all the studies examined. High-frequency rTMS over the motor cortex areas for migraine improved migraine frequency in seven of eight studies. Two of the eight studies were randomized controlled trials at low risk for biases and found high-frequency rTMS over the motor cortex areas effective in improving migraine frequency and severity. Other details of treatment prescription and symptoms were also examined.

Conclusion:

High-frequency rTMS over the motor cortex areas for migraine demonstrated efficacy as a migraine treatment, had minimal side effects, and should be further investigated.

Transcranial Magnetic Stimulation for the Treatment of Pediatric Neurological Disorders

PURPOSE OF REVIEW

Repetitive transcranial magnetic stimulation (rTMS) is a form of noninvasive brain stimulation that is used for the treatment of migraine and major depression in adults and is now being evaluated for use in other disorders. The purpose of this review is to summarize the physiology underlying TMS, the safety and tolerability in pediatric patients, and the evidence for TMS efficacy in the treatment of pediatric neurologic disorders.

RECENT FINDINGS

Studies investigating rTMS for adolescent depression, hemiparesis due to pediatric stroke, autism, and tics/Tourette syndrome have demonstrated some therapeutic benefit. rTMS has been insufficiently studied for migraine in children despite benefits demonstrated for adult migraine. Evidence for rTMS in childhood epilepsy and ADHD remains mixed. Repetitive transcranial magnetic stimulation is emerging as a safe, tolerable, and potentially effective therapeutic strategy in a number of pediatric neurological disorders, though high-quality, randomized controlled trials are needed. Ongoing studies should focus on optimization of treatment protocols, development of biomarkers to identify children who will benefit from the technique, and identification of the most appropriate indicators of response.

Treatment of Persistent Post-Traumatic Headache and Post-Concussion Symptoms Using Repetitive Transcranial Magnetic Stimulation: A Pilot, Double-Blind, Randomized Controlled Trial

Persistent post-traumatic headache (PTH) after mild traumatic brain injury is one of the most prominent and highly reported persistent post-concussion symptoms (PPCS). Non-pharmacological treatments, including non-invasive neurostimulation technologies, have been proposed for use. Our objective was to evaluate headache characteristics at 1 month after repetitive transcranial magnetic stimulation (rTMS) treatment in participants with PTH and PPCS. A double-blind, randomized, sham-controlled, pilot clinical trial was performed on 20 participants (18-65 years) with persistent PTH (International Classification of Headache Disorders, 3rd edition) and PPCS (International Classification of Diseases, Tenth Revision). Ten sessions of rTMS therapy (10 Hz, 600 pulses, 70% resting motor threshold amplitude) were delivered to the left dorsolateral pre-frontal cortex. The primary outcome was a change in headache frequency or severity at 1 month post-rTMS. Two-week-long daily headache diaries and clinical questionnaires assessing function, PPCS, cognition, quality of life, and mood were completed at baseline, post-treatment, and at 1, 3, and 6 months post-rTMS. A two-way (treatment × time) mixed analyisis of variance indicated a significant overall time effect for average headache severity (F_(3,54) = 3.214; p = 0.03) and a reduction in headache frequency at 1 month post-treatment (#/2 weeks, REAL -5.2 [standard deviation {SD} = 5.8]; SHAM, -3.3 [SD = 7.7]). Secondary outcomes revealed an overall time interaction for headache impact, depression, post-concussion symptoms, and quality of life. There was a significant reduction in depression rating in the REAL group between baseline and 1 month post-treatment, with no change in the SHAM group (Personal Health Questionnaire-9; REAL, -4.3 [SD = 3.7[ p = 0.020]; SHAM, -0.7 [SD = 4.7; p = 1.0]; Bonferroni corrected). In the REAL group, 60% returned to work whereas only 10% returned in the SHAM group (p = 0.027). This pilot study demonstrates an overall time effect on headache severity, functional impact, depression, PPCS, and quality of life after rTMS treatment in participants with persistent PTH; however, findings were below clinical significance thresholds. There was a 100% response rate, no dropouts, and minimal adverse effects, warranting a larger phase II study. Clinicaltrials.gov: NCT03691272.

[Transcranial magnetic stimulation in the diagnostic and treatment of pain syndromes in children and adults]

The authors review the literature and own data concerning therapeutic use of transcranial magnetic stimulation (TMS) in children and adult patients with pain syndromes of different origins. TMS may act as a tool to excite or inhibit neuroplasticity in the central nervous system, which depends of the therapeutic regime used. TMS induces neurogenesis and synaptogenesis, rhythmic TMS may cause long-lasting after-effects, including pain inhibitory effect. A decrease in the threshold and an increase in the amplitude of motor evoked potentials in TMS are the most frequent changes in pain syndromes in the diagnostic modality. The efficacy of different regimes in the treatment of pain syndromes remains understudied. Despite vast knowledge on clinical use of TMS in pain syndromes in adults, in pediatrics its use is limited to migraine treatment. TMS is a valuable diagnostic and therapeutic tool that should be more often implemented in neurorehabilitation and treatment of neurological diseases in adults and children with pain syndromes.

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.

Anatomical Variations of the Supraorbital and Supratrochlear Nerves: Their Intraorbital Course and Relation to the Supraorbital Margin

Background

This study aimed to describe the topographical anatomy of the supraorbital and supratrochlear nerves. Anatomical variations of both the intraorbital course of the 2 nerves and their relation to the supraorbital margin were analyzed.

Material/Methods

The research material involved 50 isolated adult cadaveric hemi-heads and 25 macerated adult skulls. All studied specimens were of Caucasian origin.

Results

Taking into account the location of the frontal nerve division, 2 main variants of the intraorbital course of the supraorbital and supratrochlear nerves were distinguished. The first variant (variant I, 42%) involved cases in which the supraorbital and supratrochlear nerves branched off from the frontal nerve in the distal half of the length of the orbit. In the second variant (variant II, 58%), the frontal nerve branched into the supraorbital and supratrochlear nerves in the proximal half of the orbit. Variant II was characterized by the presence of a thick supraorbital nerve and a long, tiny supratrochlear nerve. For variant I, 27.8% of the supraorbital nerves were divided into the medial and lateral branch within the orbit, whereas, for variant II, 75% of nerves were divided into the medial and lateral branch within the orbit (before crossing the supraorbital margin). Single passage was observed on the supraorbital margin in 80% of wet specimens and in 78% of orbits examined on the macerated skulls.

Conclusions

Both the intraorbital and extraorbital course of the branches of the supraorbital and supratrochlear nerves were highly diverse. These variations should be taken into account during medical procedures performed within the orbital and frontal regions.

[New horizons for acute and prophylactic treatments of migraine]

The current treatment of migraine attacks is triptans and NSAIDs, but the calcitonin gene-related peptide (CGRP) has emerged as a key neuropeptide target for migraine therapy. Despite an off target class effect on liver enzymes, two CGRP receptor antagonists, ubrogepant and rimegepant, remain in development, together with a 5-HT_1F receptor agonist (lasmiditan), for which cardiovascular contraindications that limit the utility of triptans do not exist. Importantly, to avoid an excessive use of acute medication with the risk of medication overuse, prophylactic therapeutics are the best choice. To date, monoclonal antibodies which block CGRP actions are on the market all over the world but not yet in France. The research is very active in different directions and targets notably hypothalamic neuropeptides because the hypothalamus hosts many key neuropeptide systems that seem to play a role in migraine physiopathology. These neuropeptides include orexins, oxytocin, neuropeptide Y (NPY) and pituitary adenylate cyclase-activating polypeptide (PACAP). In addition, other promising drugs for the treatment of migraine are nitric oxide synthase inhibitors and acid-sensing ion channel (ASIC) blockers.

Non-invasive neuromodulation for migraine and cluster headache: a systematic review of clinical trials

Non-invasive neuromodulation therapies for migraine and cluster headache are a practical and safe alternative to pharmacologics. Comparisons of these therapies are difficult because of the heterogeneity in study designs. In this systematic review of clinical trials, the scientific rigour and clinical relevance of the available data were assessed to inform clinical decisions about non-invasive neuromodulation. PubMed, Cochrane Library and ClinicalTrials.gov databases and the WHO's International Clinical Trials Registry Platform were searched for relevant clinical studies of non-invasive neuromodulation devices for migraine and cluster headache (1 January 1990 to 31 January 2018), and 71 were identified. This analysis compared study designs using recommendations of the International Headache Society for pharmacological clinical trials, the only available guidelines for migraine and cluster headache. Non-invasive vagus nerve stimulation (nVNS), single-transcranial magnetic stimulation and external trigeminal nerve stimulation (all with regulatory clearance) were well studied compared with the other devices, for which studies frequently lacked proper blinding, sham controls and sufficient population sizes. nVNS studies demonstrated the most consistent adherence to available guidelines. Studies of all neuromodulation devices should strive to achieve the same high level of scientific rigour to allow for proper comparison across devices. Device-specific guidelines for migraine and cluster headache will be soon available, but adherence to current guidelines for pharmacological trials will remain a key consideration for investigators and clinicians.

Endogenous Neurostimulation and Physiotherapy in Cluster Headache: A Clinical Case

OBJECTIVE

The aim of this paper is to describe the progressive changes of chronic cluster headaches (CHs) in a patient who is being treated by a multimodal approach, using pharmacology, neurostimulation and physiotherapy.

SUBJECT

A male patient, 42 years of age was diagnosed with left-sided refractory chronic CH by a neurologist in November 2009. In June 2014, the patient underwent a surgical intervention in which a bilateral occipital nerve neurostimulator was implanted as a treatment for headache.

METHODS

Case report.

RESULTS

Primary findings included a decreased frequency of CH which lasted up to 2 months and sometimes even without pain. Besides this, there were decreased levels of anxiety, helplessness (PCS subscale) and a decreased impact of headache (HIT-6 scale). Bilateral pressure pain thresholds (PPTs) were improved along with an increase in strength and motor control of the neck muscles. These improvements were present at the conclusion of the treatment and maintained up to 4 months after the treatment.

CONCLUSIONS

A multimodal approach, including pharmacology, neurostimulation and physiotherapy may be beneficial for patients with chronic CHs. Further studies such as case series and clinical trials are needed to confirm these results.

Noninvasive neuromodulation in migraine and cluster headache

PURPOSE OF REVIEW

The purpose of this narrative review is to provide an overview of the currently available noninvasive neuromodulation devices for the treatment of migraine and cluster headache.

RECENT FINDINGS

Over the last decade, several noninvasive devices have undergone development and clinical trials to evaluate efficacy and safety. Based on this body of work, single-pulse transcranial magnetic stimulation, transcutaneous supraorbital neurostimulation, and noninvasive vagal nerve stimulation devices have been cleared by the United States Food and Drug Administration and are available for clinical use for the treatment of primary headache disorders.

SUMMARY

Overall, these novel noninvasive devices appear to be safe, well tolerated, and have demonstrated promising results in clinical trials in both migraine and cluster headache. This narrative review will provide a summary and update of the proposed mechanisms of action, evidence, safety, and future directions of various currently available modalities of noninvasive neuromodulation for the treatment of migraine and cluster headache.

A new era in headache treatment

Primary headache disorders, such as migraine and cluster headache, are common and often debilitating. When preventive therapy is needed, several oral medications are used. Patients tend to have poor adherence and persistence on their preventive therapy. The introduction of treatments blocking calcitonin gene-related peptide (CGRP) is anticipated to begin a new era in migraine preventive treatment. In addition, non-triptan serotonin receptor agonists, newer delivery systems for older therapies, and innovative devices represent other exciting advances in acute and preventive migraine and cluster treatment and shall also be discussed in this review.

Migraine and cluster headache - the common link

Although clinically distinguishable, migraine and cluster headache share prominent features such as unilateral pain, common pharmacological triggers such glyceryl trinitrate, histamine, calcitonin gene-related peptide (CGRP) and response to triptans and neuromodulation. Recent data also suggest efficacy of anti CGRP monoclonal antibodies in both migraine and cluster headache. While exact mechanisms behind both disorders remain to be fully understood, the trigeminovascular system represents one possible common pathophysiological pathway and network of both disorders. Here, we review past and current literature shedding light on similarities and differences in phenotype, heritability, pathophysiology, imaging findings and treatment options of migraine and cluster headache. A continued focus on their shared pathophysiological pathways may be important in paving future treatment avenues that could benefit both migraine and cluster headache patients.

Factors Associated with Direct Health Care Costs Among Patients with Migraine

BACKGROUND

Migraine imposes substantial economic burden on patients and the health care system. Approximately 18% of women and 6% of men suffer from migraine in the United States. This is a heterogeneous group, and little data are available to evaluate factors associated with migraine costs.

OBJECTIVE

To evaluate characteristics associated with high costs among commercially insured patients with migraine.

METHODS

This retrospective analysis identified patients with migraine in the Truven Health MarketScan Research Databases between January 2008 and June 2013. Patients were required to have 12 months continuous enrollment before and after migraine diagnoses and/or migraine-specific medications (index date). Patients with costs greater than the top 25th percentile of all-cause costs during the 12-month post-index period were classified into the upper quartile (UQ) cohort. Multiple logistic regression was used to evaluate demographic and clinical factors associated with being in the UQ cohort, and generalized linear models were used to estimate the incremental costs by select factors after controlling for other covariates.

RESULTS

In the total population, 857,073 patients (mean [SD] age: 43.2 [12.5] years), were included, with 83.2% females. Average post-index annual all-cause costs were $13,045 (SD = $25,328) with the top 25th percentile of costs at $14,120. Overall, 44.4% and 54.8% of patients had ≥ 1 pre-index claim for opioids and triptans, respectively. Patients with ≥ 2 migraine-related emergency room visits were twice as likely to be in the UQ cohort (OR = 2.13, 95% CI = 2.02-2.25; P < 0.05) and incurred $3,125 incremental all-cause costs compared with those with < 2 visits. Patients who visited a neurologist were 33.0% more likely to be in the UQ cohort and had significantly higher adjusted all-cause costs ($11,794 vs. $9,868, P < 0.05). Opioid users had a 1.5-3 times increased likelihood of being in the UQ cohort (P < 0.05); adjusted all-cause annual costs ranged from $8,888 (95% CI = $8,862-$8,914) for nonusers to $15,210 (95% CI = $15,113-$15,307) for high users (7+ claims). Patients having 7+ triptan claims were 1.2 times as likely to be in the UQ cohort compared with nonusers, with estimated costs of $11,517 (95% CI = $11,438-$11,596) for high users and $10,753 (95% CI = $10,717-$10,790) for nonusers.

CONCLUSIONS

Results suggest that certain modifiable factors, such as increased acute medication use (opioids and triptans) and more migraine-related emergency room visits are associated with higher all-cause health care costs for patients with migraine. These findings could be used to identify patients who require early intervention, enhanced symptoms monitoring, and appropriate disease management. Future studies could examine the effect of disease severity on health resource utilization and costs using survey or medical record data.

DISCLOSURES

This study was funded by Amgen and conducted by Truven Health Analytics. Bonafede, Cappell, and Kim are employees of Truven Health Analytics, which received compensation from Amgen for the overall conduct of the study and preparation of the manuscript. Cai was an employee of Truven Health Analytics at the time of this study. Sapra, Shah, and Desai are employees of Amgen. Katherine Widnell was an employee of Amgen when the manuscript draft was developed. Winner reports receiving research support from Allergan, Amgen, A-Z, Teva, Pfizer, Novartis, and Lilly. Study concept and design were contributed by Bonafede, Sapra, Shah, and Desai, along with Widnell and Winner. Kim and Cai took the lead in data collection, assisted by Bonafede and Cappell. Data interpretation was performed by Widnell and Winter, along with the other authors. All authors contributed to the writing and revision of the manuscript.