Diagnosis, pathophysiology and management of chronic migraine: a proposal of the Belgian Headache Society

Exploring the Therapeutic Potential of Quadripulse rTMS over the Visual Cortex: A Proof-of-Concept Study in Healthy Volunteers and Chronic Migraine Patients with Medication Overuse Headache

In chronic migraine with medication overuse (CM-MOH), sensitization of visual cortices is reflected by (i) increased amplitude of stimulus-evoked responses and (ii) habituation deficit during repetitive stimulation. Both abnormalities might be mitigated by inhibitory transcranial neurostimulation. Here, we tested an inhibitory quadripulse repetitive transcranial magnetic stimulation (rTMS-QPI) protocol to decrease durably visual cortex excitability in healthy subjects (HS) and explored its therapeutic potential in CM-MOH patients. Pattern-reversal visual evoked potentials (VEP) were used as biomarkers of effect and recorded before (T1), immediately after (T2), and 3 h after stimulation (T3). In HS, rTMS-QPI durably decreased the VEP 1st block amplitude (p < 0.05) and its habituation (p < 0.05). These changes were more pronounced for the P1N2 component that was modified already at T2 up to T3, while for N1P1 they were significant only at T3. An excitatory stimulation protocol (rTMS-QPE) tended to have an opposite effect, restricted to P1N2. In 12 CM-MOH patients, during a four-week treatment (2 sessions/week), rTMS-QPI significantly reduced monthly headache days (p < 0.01). In patients reversing from CM-MOH to episodic migraine (n = 6), VEP habituation significantly improved after treatment (p = 0.005). rTMS-QPI durably decreases visual cortex responsivity in healthy subjects. In a proof-of-concept study of CM-MOH patients, rTMS-QPI also has beneficial clinical and electrophysiological effects, but sham-controlled trials are needed.

The childhood migraine syndrome

Migraine is a complex genetic brain disorder with an intricate pathogenesis and polymorphous clinical presentations, particularly in children. In this Perspective, we describe the different phenotypes of migraine in children, including conditions that have been referred to in the International Classification of Headache Disorders as "syndromes that may be related to migraine''. Evidence is presented for the integration of abdominal migraine, cyclical vomiting syndrome, benign paroxysmal vertigo, benign paroxysmal torticollis and infantile colic into the unified diagnosis of 'childhood migraine syndrome' on the basis of clinical and epidemiological characteristics, and shared inheritance. In our opinion, such integration will guide clinicians from specialities other than neurology to consider migraine in the assessment of children with these disorders, as well as stimulate research into the genetics, pathophysiology and clinical features of all disorders within the syndrome. A diagnosis of childhood migraine syndrome would also enable patients to benefit from inclusion in clinical trials of old and new migraine treatments, thus potentially increasing the number of treatment options available.

Monoclonal antibodies blocking CGRP transmission: An update on their added value in migraine prevention

The avenue of effective migraine therapies blocking calcitonin gene-related peptide (CGRP) transmission is the successful outcome of 35 years of translational research. Developed after short-acting, the small antagonists of the CGRP receptor (the "gepants"), the monoclonal antibodies blocking CGRP or its receptor (CGRP/rec mAbs) have changed the paradigm in migraine treatment. Contrary to the classical acute medications like triptans or nonsteroidal anti-inflammatory drugs (NSAIDs) with a transient effect, they act for long durations exclusively in the peripheral portion of the trigeminovascular system and can thus be assimilated to a durable attack treatment, unlike the classical preventives that chiefly act upstream on the central facets of migraine pathophysiology. Randomized controlled trials (RCT) of eptinezumab, erenumab, fremanezumab and galcanezumab have included collectively several thousands of patients, making them the most extensively studied class of preventive migraine treatments. Their results clearly indicate that CGRP/rec mAbs are significantly superior to placebo and have been comprehensively reviewed by Dodick [Cephalalgia 2019;39(3):445-458]. In this review we will briefly summarize the placebo-subtracted outcomes and number-needed-to-treat (NNT) of these pivotal RCTs and analyze new and post-hoc studies published afterwards focusing on effect size, effect onset and sustainability, response in subgroups of patients, safety and tolerability, and cost-effectiveness. We will also summarize our limited real-world experience with one of the CGRP/rec mAbs. Although methodological differences and lack of direct comparative trials preclude any reliable comparison, the overall impression is that there are only minor differences in efficacy and tolerability profiles between the four monoclonals: the average placebo-subtracted 50% responder rates for reduction in migraine headaches are 21.4% in episodic migraine (NNTs: 4-5), 17.4% in chronic migraine (NNTs: 4-8). Patients with an improvement exceeding 50% are rare, chronic migraineurs with continuous headache are unlikely to be responders and migraine auras are not improved. The effect starts within the first week after administration and is quasi maximal at one month. It is sustained for long time periods and may last for several months after treatment termination. CGRP/rec mAbs are effective even after prior preventive treatment failures and in patients with medication overuse, but the effect size might be smaller. They significantly reduce disability and health care resource utilization. The adverse effect profile of CGRP/rec mAbs is close to that of placebo with few minor exceptions and despite concerns related to the safeguarding role of CGRP in ischemia, no treatment-related vascular adverse events have been reported to date. Putting the CGRP/rec mAbs in perspective with available preventive migraine drug treatments, their major advantage seems not to be chiefly their superior efficacy but their unprecedented efficacy over adverse event ratio. Regarding cost-effectiveness, preliminary pharmaco-economic analyses of erenumab suggest that it is cost-effective for chronic migraine compared to no treatment or to onabotulinumtoxinA, but likely not for episodic migraine unless attack frequency is high, indirect costs are considered and its price is lowered.

Could rs4379368 be a genetic marker for North Indian migraine patients with aura?: Preliminary evidence by a replication study

BACKGROUND

Genome wide association studies (GWAS) have already found different migraine single nucleotide polymorphisms (SNPs). To further check if these variants differ by ethnicity, three single nucleotide polymorphisms (SNPs) (rs4379368, rs10504861and rs11172113) were genotyped here to find association with migraine susceptibility from North Indian population.

METHODS AND RESULTS

A case control study in 200 subjects was done by polymerase chain reaction and restriction-fragment-length polymorphism (PCR-RFLP) analysis. Univariate analysis was performed to check the association of different genotypic and allelic frequencies of these variants with migraine and its subtypes. We could not find any statistically relevant differences among frequencies at various levels of these selected SNPs between patients and healthy controls in this study (p > 0.05). However on subgroup analysis for rs4379368 SNP, the CT genotype was higher in migraine with aura (MA) (69.6%) than migraine without aura (MO) (51.9%) or control (42%) (p < 0.05). But this relation was not significant at allelic level. For other two SNPs, statistically significant differences were not observed in any of the two migraine subgroups.

CONCLUSIONS

This study was able to associate the role of rs4379368 SNP with migraine susceptibility and suggested that genotype CT in rs4379368 SNP could be a possible genetic marker for MA. More studies with larger sample size are needed to strengthen our results.

Efficacy and safety of external trigeminal neurostimulation in the prevention of chronic migraine: An open-label trial

Objective:

This trial explored the therapeutic utility and safety of external trigeminal neurostimulation (eTNS) as a preventive treatment in patients suffering from chronic migraine (CM).

Methods:

It was a monocenter, prospective, open-label, pilot trial conducted at the University of Colorado, Anschutz Medical Campus (Aurora, CO, USA). Participants were adult patients with a history of CM meeting International Classification of Headache Disorder-3 beta (2013) diagnostic criteria with or without medication overuse. After a 1-month baseline period, the patients still fulfilling the inclusion criteria applied at least one daily 20-min session of eTNS for 3 months. Primary outcomes were mean monthly changes in frequency of headache days and in overall acute headache medication intake.

Results:

Eighty patients were assessed for eligibility, 73 were included in the baseline period after which 58 entered the treatment period and were included in the intention-to-treat analysis. Compared to baseline, frequency of headache days decreased by −3.12 days (−16.21%, p < 0.001) and acute medication intake decreased from 26.33 to 18.22 (−30.81%, p < 0.001) during the third month of treatment. Twenty-six patients reported 47 minor adverse events, of which only 2 were related to the use of the device (skin irritation under the electrode and headache worsening with vertigo).

Conclusions:

This trial suggests that eTNS is safe and effective as prophylactic treatment for CM and indicates that a randomized sham-controlled trial is worthwhile.

Trial registration:

ClinicalTrials.gov (identifier: NCT02342743).

Protein Kinase C γ Contributes to Central Sensitization in a Rat Model of Chronic Migraine

Protein kinase C γ (PKCγ) is a critical regulator of central sensitization and is widely recognized to be involved in the pathogenesis of chronic migraine (CM). However, the function of PKCγ in CM remains unknown. This study investigated the role of PKCγ on pathogenesis of CM. We repeated infusions of inflammatory soup (IS) on the intact dura of conscious rats to model recurrent trigeminovascular or dural nociceptor activation assumed to occur in patients with CM. The von Frey test was then used to detect changes in pain threshold. QT-PCR, western blotting, and double immunofluorescence staining were performed to detect the expression and location of PKCγ in the trigeminal nucleus caudalis (TNC) and the expressions of calcitonin gene-related peptide (CGRP), c-Fos, and phosphorylation level of GluR1 subunit at serine 831. Chelerythrine chloride (CHE) and phorbol 12-myristate 13-acetate (PMA) were administrated to investigate the role of PKCγ in central sensitization. We found that repeated infusions of IS induced mechanical allodynia. PKCγ was significantly increased in TNC after CM. Furthermore, inhibition of PKCγ by CHE relieved allodynia and reduced the expression of CGRP and c-Fos. Activation of PKCγ by PMA aggravated allodynia and increased the expression of CGRP and c-Fos. In addition, inhibition of PKCγ reduced the phosphorylation level of GluR1; in contrast, activation of PKCγ increased the phosphorylation level of GluR1. These results suggest PKCγ-induced GluR1 phosphorylation might participate in central sensitization in a rat model of CM. We suggest that PKCγ is a potential therapeutic target for CM.

Analysis of the upper cervical spine stiffness during axial rotation: A comparative study among patients with tension-type headache or migraine and asymptomatic subjects

BACKGROUND

Many studies reported the implication of the cervical musculoskeletal system in patients with tension type headache and migraine. The objective of this study is to investigate the upper cervical spine stiffness features in axial rotation among headache patients in comparison with a healthy population.

METHODS

48 subjects including 30 migraine patients with/without aura and 18 patients with tension-type headache, aged between 18 and 60years (mean 36, SD 11years) have been evaluated. Stiffness measurements were carried out for passive axial rotation using a torque meter device. The flexion-rotation test was used to emphasize assessment of the upper cervical spine.

FINDINGS

Neither the stiffness nor the neutral zone varies between different populations studied. Passive range of motion in axial rotation is unilaterally reduced in symptomatic subjects (p=0.001). Considering the elastic zone, right and left motion magnitude was significantly lower for clinical groups compared to the control group.

INTERPRETATION

Stiffness seems not to be altered among tension type headache and migraine patients. However, patients seem prone to display a larger right-left asymmetry of axial rotation and a reduction in the motion range tolerance, emphasizing the likely link between the cervical discomfort and these pathologies. Any difference is observed in the elastic behavior of the upper cervical spine between the two primary headache populations. However, further investigations are needed to confirm these previous results taking various specific clinical characteristics into consideration.

Migraine Susceptibility Genes in Han Chinese of Fujian Province

Background and Purpose

Five single-nucleotide polymorphisms (SNPs) (rs4379368, rs10504861, rs10915437, rs12134493 and rs13208321) were recently identified in a Western population with migraine. These migraine-associated SNPs have not been evaluated in a Han Chinese population. This study investigated the associations of specific SNPs with migraine in a Han population.

Methods

This was a case-control study of Han Chinese residing in Fujian Province. Polymerase chain reaction—restriction-fragment-length polymorphism analysis and direct sequencing were used to characterize the relationships of SNPs in a control group of 200 subjects and in a migraine group of 201 patients.

Results

The frequencies of the five SNPs did not differ between patients with migraine and healthy non migraine controls. However, subgroup analysis indicated certain SNPs were more strongly associated with migraine with aura or migraine without aura than with controls. The CT genotype of rs4379368 was more common in migraine patients with aura (75%) than in migraine patients without aura (47.9%) and controls (48.5%) (p<0.05), and the TT genotype of rs10504861 was more common in migraine patients with aura than in controls (8.3% vs. 0.5%) (p<0.05). Meanwhile, the CC genotype of rs12134493 was less common in migraine patients without aura than in controls (80.6% vs. 88%) (p<0.05).

Conclusions

Our findings suggest that the rs4379368 and rs10504861 SNPs are markers for susceptibility to migraine with aura and that rs12134493 is a marker for the risk of migraine without aura in this Han population. Future studies should further explore if these associations vary by ethnicity.

Association of genetic loci for migraine susceptibility in the she people of China

Background

The purpose of this study was to investigate the association of the genotype and allele frequencies of the polymorphisms rs4379368, rs10504861, rs10915437, rs12134493 and rs13208321 in She people of China with migraine headache susceptibility. The five alleles were previously identified as being associated with migraine in a Western population, but it was not known if this association would hold in a She population. rs4379368 is in the succinic HMG coenzyme A transferase (C7orf10) gene; rs10504861 is near the matrix metallopeptidase 16 (MMP16) gene; rs10915437 is near the adherens junctions associated protein 1 (AJAP1) gene; rs12134493 is upstream of the tetraspanin 2 (TSPAN2) gene; and rs13208321 is within the four and a half LIM domains protein 5 (FHL5) gene.

Methods

This was a case-controlled study conducted in She people of Fujian province in China. Polymerase chain reaction-restriction fragment length polymorphism and direct sequencing were performed. Univariate and multivariate analyses were used to assess the association of the different genotypes of each SNP with migraine.

Results

The rs4379368 T allele was not in Hardy-Weinberg equilibrium and was more common than the C allele in subjects with migraine (58.7 %; P = 0.049), possibly suggesting a selection bias for T allele in this population. In support of this, the CT and TT genotypes were more frequent in the migraine compared with the control groups (54.0 % and 31.7 % vs. 48.0 % and 28.7 %, respectively; P = 0.019). These genotypes were also more common in females with migraines than females without migraines (53.8 % and 30.9 % vs. 46.7 % and 27.6 %; P = 0.026). Univariate and multivariate analyses found the CC genotype of rs4379368 and AA or AG genotype of rs13208321 were associated with a reduced risk of migraine (P values ≤0.039).

Conclusions

Our findings suggest that rs4379368 and rs13208321 are potential genetic markers for migraine in this She population. The findings of this study and others indicate important differences between ethnic populations in regard to genetic markers of migraine susceptibility.

Electronic supplementary material

The online version of this article (doi:10.1186/s10194-015-0553-1) contains supplementary material, which is available to authorized users.

Medication overuse and chronic migraine: a critical review according to clinical pharmacology

INTRODUCTION

Chronic migraine is often complicated by medication-overuse headache (MOH), a headache due to excessive intake of acute medications. Chronic migraine and MOH are serious and disabling disorders. Since chronic migraine derives from the progression of originally episodic migraine, the fundamental therapeutic strategy is prevention. This narrative review describes how to try to prevent the development of MOH and how to manage it once it has appeared.

AREAS COVERED

A PubMed database search (from 1988 to January 2015) and a review of published studies on chronic migraine and MOH were conducted.

EXPERT OPINION

In spite of progress in migraine treatment, the prevalence of chronic headaches and MOH has not changed in the course of time. Today, a large number of migraine patients have turned to numerous expert physicians and experienced all sorts of prophylactic treatments without decisive benefits. Their condition seems to have crystallized even more as chronic and intractable. This means that to prevent chronification and MOH, we need more effective drugs and better strategies to use them. In particular, we must detect disease biomarkers and predictive factors for drug response that allow for personalized treatment when migraine is still episodic and make analgesic overuse pointless.