Tackling chronic migraine: current perspectives

Cerebrovascular reactivity after functional activation of the Brain using Photic Stimulation in Migraine and Tension Type Headache: a transcranial doppler Ultrasonography Study

BACKGROUND

Previous studies in headache patients measured the cerebrovascular reactivity (CVR) in response to photic stimulation but they have yielded contradictory results. The purpose of study was to measure CVR of both migraine and chronic tension headache (TTH) patients in response to photic stimulation.

METHODS

The study included 37 migraineurs and 24 chronic TTH patients compared with 50 age- and sex-matched healthy volunteers. Peak systolic, end diastolic, mean flow velocities and CVR (PSV, EDV, MFV, and CVR) were measured using TCD ultrasonography of the middle, anterior, posterior cerebral and vertebral arteries (MCA, ACA, PCA, and VA) before and after 100 s of 14 Hz photic stimulation.

RESULTS

A three-way repeated measures ANOVA interaction with main factors of Vessels (MCA, ACA, PCA, VA), Time (pre-post photic) and Groups (migraine, TTH, and control group) revealed significant 3-way interactions for measures of PSV (P = 0.012) and MFV (P = 0.043). In the migraine patients there was significantly higher PSV, EDV, and MFV in the MCA, ACA, and PCA after photic stimulation compared with baseline. The CVR of the MCA was also significantly higher in migraineurs than controls. In the TTH group, there was significantly higher PSV, EDV, and MFV (P = 0.003, 0.012, 0.002 respectively) in the VA after photic stimulation than at baseline. The CVR was significantly higher in the VA of TTH patients than controls.

CONCLUSION

Compared with controls after photic stimulation, the higher CVR of the MCA in migraineurs and of the VA in TTH patients could be used as diagnostic tool to differentiate between the two types of headaches.

Gender Differences in the Prevalence and Characteristics of Pain in Spain: Report from a Population-Based Study

OBJECTIVE

To assess the prevalence and characteristics of chronic neck pain, chronic low back pain, and migraine or frequent headaches among Spanish adults in 2014 according to gender, to identify predictors for each of these types of pains, and to compare the prevalence with those found in 2009.

DESIGN

Cross-sectional study.

SETTING

Spain.

METHODS

We used data collected from the 2014 European Health Interview Survey (N = 22,842). Sociodemographic features, self-rated health status, lifestyle habits, comorbid conditions, pain characteristics, and self-reported use of medications were analyzed.

RESULTS

The prevalence of all types of pain was significantly higher among women than men. For chronic neck pain, the figures were 25.68% vs 12.54%, for chronic low back pain, 27.03% vs 18.83%, and for migraine or frequent headaches, 15.93% vs 6.74%, in women and men, respectively. Predictors of these types of pain included female gender, advanced age, poor self-rated health, psychological distress, comorbidities, and obesity. The prevalence of neck pain and low back pain increased from 2009 to 2014 for both sexes, and the prevalence of migraine or frequent headaches remained stable over time.

CONCLUSIONS

The prevalence and intensity of all the forms of chronic pain were higher among women. Women experiencing pain used prescribed medications for pain, anxiety, and/or depression and sleeping pills more than men. The prevalence of chronic neck and low back has increased in the last five years in Spain, and the prevalence of migraine or frequent headaches has remained stable.

Levels and determinants of knowledge about chronic migraine diagnosis and management among primary health-care physicians in ministry of health, Jeddah 2019

Background:

Chronic migraine (CM) poses a significant burden for patients, and it has multiple diagnostic and managemental challenges, particularly among primary health-care physicians (PCPs).

Objectives:

The objective of this study is to assess the levels of knowledge regarding CM diagnosis and management among PCPs and to explore the factors associated with poor knowledge.

Methods:

A cross-sectional study was conducted among PCPs working at primary health-care centers in Jeddah, Saudi Arabia. A semi-structured questionnaire comprising 20 items related to CM diagnosis and treatment was used.

Results:

A total of 136 PCPs responded (aged 36.4 ± 8.1, 68.4% were females). The overall median (P75) knowledge score was 13.0 (15.0), and 45.6% of the participants had adequate knowledge (score > median). The majority of respondents (>50%) could not identify the lower limits of CM duration, the necessity of identifying at least eight migraine attacks in a month, the importance of managing medication overuse, and the indication of topiramate as the most efficacious agent in CM. Young physicians (23–35 years), bachelor graduates, general practitioners (GPs), and those having ≤5 years of experience scored lower than their peers. Physicians with 6–10 years of clinical experience were independently more knowledgeable than less-experienced PCPs (odds ratio = 5.09, P = 0.006).

Conclusion:

Knowledge regarding CM diagnosis and treatment was inadequate among PCPs, which could detrimentally influence the patterns of referral to secondary health-care facilities. Given these observations, it is recommended to amend the academic curricula for medical students/GPs and adopt continuing medical education programs for PHPs to support their levels of knowledge.

Comparison of two ultrasound-guided techniques for greater occipital nerve injections in chronic migraine: a double-blind, randomized, controlled trial

Background and objectives

Two ultrasound (US)-guided techniques for greater occipital nerve (GON) block have been described for the management of headache disorders: a “proximal or central” technique targeting the GON at the level of the second cervical vertebra and a “distal or peripheral” technique targeting the GON at the level of the superior nuchal line. In this multicenter, prospective, randomized control trial, we compared accuracy, effectiveness, and safety of these two techniques in patients with chronic migraines (CMs).

Methods

Forty patients with refractory CMs were randomized to receive either a proximal or distal US-guided GON block with bupivacaine and methylprednisolone acetate. The primary outcome was the difference in Numerical Rating Score (NRS) for headache intensity at 1 month. Secondary outcomes were effectiveness, performance, and safety-related. Effectiveness-related outcomes included NRS for headache intensity, number of headache days per week, patient satisfaction, quality of life, assessment of sleep quality, and sleep interruption. Performance-related outcomes included procedure time, accuracy of block, and patient discomfort. Safety-related outcomes included an assessment for adverse effects.

Results

NRS pain scores were significantly reduced at 24 hours and at 1 week postprocedure in both cohorts and at 1 and 3 months in the proximal group as compared with the baseline. There was no significant difference in NRS pain scores between the two cohorts at any of the follow-up time points. There was a significant reduction in number of headache days per week at 1 month in both groups, and a significant improvement in sleep interruption at 1 week in both groups. There were no significant adverse effects.

Conclusions

This study was designed to compare two different US-guided approaches for blocking the GON. Our results demonstrate that both distal and proximal techniques can provide a short-term improvement in headache intensity, reduction in number of headache days per week, and an improvement in sleep interruption. The proximal GON technique may confer more sustained analgesic benefit compared with the distal approach in patients with CM headaches.

Trial registration number

NCT02031822.

Conditions Associated with Essential Tremor in Veterans: A Potential Role for Chronic Stress

Background

Increased depression, hearing loss, dementia, alcoholism, and mortality in essential tremor patients remain unexplained. We investigated whether conditions associated with tremor are linked to chronic stress.

Methods

The FY2013 Veterans Affairs database was queried for 38 selected dual diagnosis combinations in 5,854,223 veterans aged 21–95 years.

Results

Post-traumatic stress disorder, anxiety, and depression were the most common psychiatric diagnoses in tremor patients, with the odds ratio exceeding 2 in all 15-year cohorts. Depending on age, patients with essential tremor were more likely than those without to have obsessive–compulsive disorder, bipolar illness, schizophrenia, use tobacco and abuse alcohol, have hypertension, obesity, hyperlipidemia, diabetes, vitamin D deficiency, coronary and cerebrovascular diseases, congestive heart failure, stroke, asthma, hypothyroidism, irritable bowel syndrome, renal insufficiency, alcoholic liver disease, hearing loss, glaucoma, macular degeneration, migraine, epilepsy, idiopathic polyneuropathy, history of head trauma, and ‘Alzheimer’s dementia. In contrast, lung and colorectal cancer, amyotrophic lateral sclerosis, psychostimulant abuse, and rheumatoid arthritis were not more common.

Discussion

Post-traumatic stress disorder, anxiety, and depression, strongly associated with essential tremor, are known risk factors for poor health habits, tobacco use and alcohol abuse; collectively these are risk factors for vascular disease, with further negative health consequences for multiple organ systems. As essential tremor is associated with all these conditions, we propose that chronic stress is not only responsible for the conditions associated with tremor but in some cases itself directly and indirectly induces essential tremor, so that tremor and poor health share a common cause.

Living with chronic migraine: a qualitative study on female patients' perspectives from a specialised headache clinic in Spain

OBJECTIVES

The aim of this study was to explore the views and experiences of a group of Spanish women suffering from chronic migraine (CM).

SETTING

Headache clinic at a university hospital in Madrid (Spain).

PARTICIPANTS

Purposeful sampling of patients that attended a specialised headache clinic for the first time between June 2016 and February 2017 was performed. The patients included were females aged 18-65 and with positive diagnoses of CM according to the International Classification of Headache disorders (third edition, beta version), with or without medication overuse. Accordingly, 20 patients participated in the study with a mean age of 38.65 years (SD 13.85).

DESIGN

Qualitative phenomenological study.

METHODS

Data were collected through in-depth interviews, researchers' field notes and patients' drawings. A thematic analysis was performed following appropriate guidelines for qualitative research.

RESULTS

Five main themes describing the significance of suffering emerged: (a) the shame of suffering from an invisible condition; (b) treatment: between need, scepticism and fear; (c) looking for physicians' support and sincerity and fighting misconceptions; (d) limiting the impact on daily life through self-control; and (e) family and work: between understanding and disbelief. The disease is experienced as an invisible process, and the journey to diagnosis can be a long and tortuous one. Drug prescription by the physician is greeted with distrust and scepticism. Patients expect sincerity, support and the involvement of their doctors in relation to their disease. Pain becomes the main focus of the patient's life, and it requires considerable self-control. The disease has a strong impact in the work and family environment, where the patient may feel misunderstood.

CONCLUSIONS

Qualitative research offers insight into the way patients with CM experience their disease and it may be helpful in establishing a more fruitful relationship with these patients.

Migraine and Suicidal Behaviors: A Systematic Literature Review

OBJECTIVE

The aim of this systematic review was to provide a picture of suicidality (suicide ideation and behavior, both fatal and nonfatal) among indviduals with migraine.

BACKGROUND

Migraine is a leading cause of disability around the world. Migraine may manifest with a number of symptoms, ranging from severe headaches to neurological sensory disturbances. Comorbid psychological conditions, such as depression, have also been linked to chronic migraine.

DATA SOURCES

Articles were retrieved from SCOPUS, PubMed, Proquest, and Web of Science.

SEARCH TERMS

Suicid* AND migrain* in English-language peer-reviewed journals between January 1, 1966 and December 31, 2014.

ELIGIBILITY CRITERIA

Original research papers providing empirical evidence about the potential link between migraine and suicidal behaviors.

RESULTS

Initial search identified 510 papers; the titles and abstracts of 360 unique results were examined for their relevance to the combination of migraine and suicidality. In total, 17 papers reporting original empirical analyses were included in this review.

CONCLUSIONS

Research has empirically documented a link between migraine and suicide ideation and behavior, particularly concerning the subtype of migraine with aura. Overall, nonfatal suicidal behavior among people with migraine has primarily been investigated, with only 2 studies analyzing suicide mortality. In addition, majority of studies originated from the United States or Canada (n=10). Future research should thoroughly define migraine and investigate link between migraine and suicide mortality.

The Insula: A "Hub of Activity" in Migraine

The insula, a "cortical hub" buried within the lateral sulcus, is involved in a number of processes including goal-directed cognition, conscious awareness, autonomic regulation, interoception, and somatosensation. While some of these processes are well known in the clinical presentation of migraine (i.e., autonomic and somatosensory alterations), other more complex behaviors in migraine, such as conscious awareness and error detection, are less well described. Since the insula processes and relays afferent inputs from brain areas involved in these functions to areas involved in higher cortical function such as frontal, temporal, and parietal regions, it may be implicated as a brain region that translates the signals of altered internal milieu in migraine, along with other chronic pain conditions, through the insula into complex behaviors. Here we review how the insula function and structure is altered in migraine. As a brain region of a number of brain functions, it may serve as a model to study new potential clinical perspectives for migraine treatment.

Outcome of Chronic Daily Headache or Chronic Migraine

Chronic daily headache (CDH) is a common neurological condition that affects 1-4% of the general population. Recent epidemiological studies have shown that CDH is mainly represented by chronic migraine (CM). Owing to the frequent headaches, associated symptoms, and comorbid conditions associated with CDH/CM, disability, quality of life (QoL), economic burden, and treatment outcome have become important personal and social issues. There have been several studies assessing the disability, QoL, and economic burden associated with CDH/CM. These studies, conducted in different settings, consistently reported significantly higher disability and economic burden and lower QoL among CDH/CM patients compared to patients with episodic headache (EH) or episodic migraine (EM). Treatment outcome of CDH/CM is often poor. In this review, we describe and summarize the results of relevant studies performed to date.

Effectiveness and safety of an extended-release tablet of sodium valproate for the prophylactic treatment of migraine: Postmarketing surveillance in Japan

BACKGROUND

Sodium valproate is a standard drug for first-line prophylactic treatment of migraine. However, little information is available of its use in Japanese patients.

AIM

To evaluate the effectiveness and safety of an extended-release tablet of sodium valproate in the prophylactic treatment for Japanese patients with migraine by postmarketing surveillance.

METHODS

This was a prospective, multicenter and non-interventional observation study in routine clinical practice. A total of 1222 patients with migraine of all age groups (aged <10 to ≤80 years) and both sexes (17.3% men and 82.7% women) from 169 sites were enrolled.

RESULTS

Migraine frequency during a 4-week period was reduced from 10.2 ± 6.0 days in 1040 patients to 5.0 ± 4.6 days in 944 patients (P < 0.001): 70.8% of patients experienced remission of migraine by ≥30%, 59.0% by ≥50% and 11.8% by ≥100%. Multivariate analysis and stratification sampling showed that this sodium valproate tablet was the most effective in patients with more migraine days, and complete remission was observed in 29% of patients whose migraine days were less than 3 days per 4 weeks at baseline. The extended-release tablet of sodium valproate reduced migraine intensity and duration of migraine attacks. The incidence of adverse drug reactions was 6.3% (67/1070 patients) and well tolerated. However, four pregnancies were discovered in this survey.

CONCLUSIONS

This first large observation study in Japan suggests that an extended-release tablet of sodium valproate is effective and safe for the prophylactic treatment of patients with migraine in routine clinical practice.

Short-term effects of greater occipital nerve blocks in chronic migraine: A double-blind, randomised, placebo-controlled clinical trial

Background Greater occipital nerve (GON) blocks are widely used for the treatment of headaches, but quality evidence regarding their efficacy is scarce. Objective The objective of this article is to assess the short-term clinical efficacy of GON anaesthetic blocks in chronic migraine (CM) and to analyse their effect on pressure pain thresholds (PPTs) in different territories. Participants and methods The study was designed as a double-blind, randomised, placebo-controlled clinical trial. Thirty-six women with CM were treated either with bilateral GON block with bupivacaine 0.5% ( n = 18) or a sham procedure with normal saline ( n = 18). Headache frequency was recorded a week after and before the procedure. PPT was measured in cephalic points (supraorbital, infraorbital and mental nerves) and extracephalic points (hand, leg) just before the injection (T0), one hour later (T1) and one week later (T2). Results Anaesthetic block was superior to placebo in reducing the number of days per week with moderate-or-severe headache (MANOVA; p = 0.027), or any headache ( p = 0.04). Overall, PPTs increased after anaesthetic block and decreased after placebo; after the intervention, PPT differences between baseline and T1/T2 among groups were statistically significant for the supraorbital (T0-T1, p = 0.022; T0-T2, p = 0.031) and infraorbital sites (T0-T1, p = 0.013; T0-T2, p = 0.005). Conclusions GON anaesthetic blocks appear to be effective in the short term in CM, as measured by a reduction in the number of days with moderate-to-severe headache or any headache during the week following injection. GON block is followed by an increase in PPTs in the trigeminal area, suggesting an effect on central sensitisation at the trigeminal nucleus caudalis. This trial is registered at ClinicalTrials.gov (NCT02188394).

Migraine incidence in 5 years: a population-based prospective longitudinal study in Turkey

BACKGROUND

The incidence of migraine has been investigated only in a few studies worldwide and it is not known in our country. We, therefore, aimed to estimate the migraine incidence in a previously accomplished population-based prevalence study sample of 5323 individuals in the year 2008.

METHODS

The former Turkish headache prevalence study has been completed as a nationwide, randomized, home-based study of face-to-face examination by physicians trained for headache diagnosis by using ICHD criteria. Five years after this study an optimized survey including 50 questions was performed to estimate the migraine incidence in migraine-free individuals in the previous study, with a 56.4 % responder rate. Two validation studies for this survey were performed prior and after the study each in 100 subjects by comparing the gold standard of expert diagnosis of headache, showing high rate of reliability (Crohnbach alpha: 0.911 and 0.706, respectively).

RESULTS

Migraine incidence was estimated as 2.38 % (2.98 % in women and 1.93 % in men) per year in 2563 migraine-free individuals; if the population at risk is defined as the group without any headaches, the migraine incidence decreased to 1.99 %. The chronic migraine (CM) incidence [without medication overuse (MOH)] was 0.066 % and that of MOH was 0.259 %. We found a significant burden of the disease on the occupational functionality as well as on social and family life, even in the early years of the migraine. The family history of headaches especially in the fathers could be useful to predict new cases of migraine, besides the well-known risk factor, diagnosis of depression, whereas income and education did not seem to relate to migraine onset.

CONCLUSIONS

Our study with a large population-based nation-wide sample, using ICHD-II criteria, with structured headache interviews as well as blinded re-validation of the questionnaire diagnoses showed a 2.38 % incidence rate of migraine in Turkey, higher than most of the other previous reports; a finding which could be related to genetic factors and also to the methodological differences in the study designs. Moreover the incidence of CM was found to be 0.066 %.

Contribution of Piezo2 to endothelium-dependent pain

Background

We evaluated the role of a mechanically-gated ion channel, Piezo2, in mechanical stimulation-induced enhancement of hyperalgesia produced by the pronociceptive vasoactive mediator endothelin-1, an innocuous mechanical stimulus-induced enhancement of hyperalgesia that is vascular endothelial cell dependent. We also evaluated its role in a preclinical model of a vascular endothelial cell dependent painful peripheral neuropathy.

Results

The local administration of oligodeoxynucleotides antisense to Piezo2 mRNA, at the site of nociceptive testing in the rat’s hind paw, but not intrathecally at the central terminal of the nociceptor, prevented innocuous stimulus-induced enhancement of hyperalgesia produced by endothelin-1 (100 ng). The mechanical hyperalgesia induced by oxaliplatin (2 mg/kg. i.v.), which was inhibited by impairing endothelial cell function, was similarly attenuated by local injection of the Piezo2 antisense. Polymerase chain reaction analysis demonstrated for the first time the presence of Piezo2 mRNA in endothelial cells.

Conclusions

These results support the hypothesis that Piezo2 is a mechano-transducer in the endothelial cell where it contributes to stimulus-dependent hyperalgesia, and a model of chemotherapy-induced painful peripheral neuropathy.

Treatment of Chronic Migraine with OnabotulinumtoxinA: Mode of Action, Efficacy and Safety

Background: Chronic migraine is a common, highly disabling, underdiagnosed and undertreated entity of migraine. It affects 0.9%–2.2% of the general adult population. The present paper overviews the preclinical and clinical data regarding the therapeutic effect of onabotulinumtoxinA in chronic migraineurs. Methods: A literature search was conducted in the database of PubMed up to 20 May 2015 for articles related to the pathomechanism of chronic migraine, the mode of action, and the efficacy, safety and tolerability of onabotulinumtoxinA for the preventive treatment of chronic migraine. Results: The pathomechanism of chronic migraine has not been fully elucidated. The mode of action of onabotulinumtoxinA in the treatment of chronic migraine is suggested to be related to the inhibition of the release of calcitonin gene-related peptide and substance P in the trigeminovascular system. Randomized clinical trials demonstrated that long-term onabotulinumtoxinA fixed-site and fixed-dose (155–195 U) intramuscular injection therapy was effective and well tolerated for the prophylactic treatment of chronic migraine. Conclusions: Chronic migraine is a highly devastating entity of migraine. Its exact pathomechanism is unrevealed. Two-third of chronic migraineurs do not receive proper preventive medication. Recent clinical studies revealed that onabotulinumtoxinA was an efficacious and safe treatment for chronic migraine.

Non-invasive vagus nerve stimulation for acute treatment of high-frequency and chronic migraine: an open-label study

BACKGROUND

The treatment of migraine headache is challenging given the lack of a standardized approach to care, unsatisfactory response rates, and medication overuse. Neuromodulation therapy has gained interest as an alternative to pharmacologic therapy for primary headache disorders. This study investigated the effects of non-invasive vagus nerve stimulation (nVNS) in patients with high-frequency episodic migraine (HFEM) and chronic migraine (CM).

FINDINGS

In this open-label, single-arm, multicenter study, patients with HFEM or CM self-treated up to 3 consecutive mild or moderate migraine attacks that occurred during a 2-week period by delivering two 120-s doses of nVNS at 3-min intervals to the right cervical branch of the vagus nerve. Of the 50 migraineurs enrolled (CM/HFEM: 36/14), 48 treated 131 attacks. The proportion of patients reporting pain relief, defined as a ≥50% reduction in visual analog scale (VAS) score, was 56.3% at 1 h and 64.6% at 2 h. Of these patients, 35.4% and 39.6% achieved pain-free status (VAS = 0) at 1 and 2 h, respectively. When all attacks (N = 131) were considered, the pain-relief rate was 38.2% at 1 h and 51.1% at 2 h, whereas the pain-free rate was 17.6% at 1 h and 22.9% at 2 h. Treatment with nVNS was safe and well tolerated.

CONCLUSION

Non-invasive vagus nerve stimulation may be effective as acute treatment for HFEM or CM and may help to reduce medication overuse and medication-associated adverse events.

Pharmacological agents for the prevention of vestibular migraine

BACKGROUND

Vestibular migraine is a common cause of episodic vertigo. Many preventive treatments have been proposed for this condition, including calcium antagonists, beta-blockers, antidepressants, anticonvulsants, selective 5-HT1 agonists, serotonin antagonists and non-steroidal anti-inflammatory drugs (NSAIDs).

OBJECTIVES

To assess the effects of pharmacological agents for the prevention of vestibular migraine.

SEARCH METHODS

The Cochrane Ear, Nose and Throat Disorders Group (CENTDG) Trials Search Co-ordinator searched the CENTDG Trials Register; Central Register of Controlled Trials (CENTRAL 2015, Issue 5); PubMed; EMBASE; CINAHL; Web of Science; Clinicaltrials.gov; ICTRP and additional sources for published and unpublished trials. The date of the search was 5 June 2015.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in adults (over 18 years) with a diagnosis of vestibular migraine orprobable vestibular migraine according to the Bárány Society/International Headache Society (IHS) criteria, treated in any setting, comparing pharmacological treatments used in the prevention of vestibular migraine, including beta-blockers, calcium antagonists, anticonvulsants, antidepressants, serotonin antagonists and non-steroidal anti-inflammatory drugs (NSAIDs) against placebo or no treatment.

DATA COLLECTION AND ANALYSIS

We used the standard methodological procedures expected by The Cochrane Collaboration.

MAIN RESULTS

Our literature search identified 558 reports, however only 11 were sufficiently relevant for further assessment. We excluded two studies because they did not use the IHS diagnostic criteria for vestibular migraine. We excluded a further eight studies for various reasons related to their design (e.g. lack of placebo or no treatment comparator), aim (e.g. treatment of vestibular migraine rather than prevention) or conduct (e.g. early termination). We identified one ongoing study comparing metoprolol to placebo. The results of this study are awaited; recruitment of the last patient is expected by the end of 2016.

AUTHORS' CONCLUSIONS

We found no evidence from RCTs to answer the question set out in the review objectives. This review has identified the need for well-designed randomised controlled trials to answer questions about the efficacy of current and new treatments.

Neurological soft signs in primary headache patients

Neurological soft signs (NSS) are semeiotic anomalies not assessed by the standard neurological examination, primarily developed in psychiatric settings and recently proposed as potential markers of minor brain circuit alterations, especially the cerebellar-thalamic-prefrontal network. Primary headache patients present with normal neurological examination and frequent psychiatric comorbidity. Aim of this exploratory study consisted in assessing NSS in 20 episodic frequent migraine (MH) and in 10 tension-type headache (ETTH) outpatients compared to 30 matched healthy controls. NSS were assessed by the Heidelberg scale; clinical characteristics and brain MRI were additionally obtained in all patients. NSS were increased by ∼70 and ∼90% in ETTH and MH, respectively, with respect to controls (p<0.001) and the difference remained significant even after controlling for age and education. Headache type and characteristics did not influence NSS presentation, while headache patients with white matter hyperintensities (WMH) at brain MRI had higher NSS scores compared both to normal controls and patients without WMH. NSS identify a subset of primary headache patients sharing the same comorbidities or minimal brain anomalies, suggesting that tailored prophylactic options might apply.

Occipital nerve stimulation for chronic migraine--a systematic review and meta-analysis

BACKGROUND

Chronic migraine is a debilitating headache disorder that has significant impact on quality of life. Stimulation of peripheral nerves is increasingly being used to treat chronic refractory pain including headache disorders. This systematic review examines the effectiveness and adverse effects of occipital nerve stimulation (ONS) for chronic migraine.

METHODS

Databases, including the Cochrane Library, MEDLINE, EMBASE, CINAHL and clinical trial registers were searched to September 2014. Randomized controlled trials (RCTs), other controlled and uncontrolled observational studies and case series (n≥ 10) were eligible. RCTs were assessed using the Cochrane risk of bias tool. Meta-analysis was carried out using a random-effects model. Findings are presented in summary tables and forest plots.

RESULTS

Five RCTs (total n=402) and seven case series (total n=115) met the inclusion criteria. Pooled results from three multicenter RCTs show that ONS was associated with a mean reduction of 2.59 days (95% CI 0.91 to 4.27, I2=0%) of prolonged, moderate to severe headache per month at 3 months compared with a sham control. Results for other outcomes generally favour ONS over sham controls but quantitative analysis was hampered by incomplete publication and reporting of trial data. Lead migration and infections are common and often require revision surgery. Open-label follow-up of RCTs and case series suggest long-term effectiveness can be maintained in some patients but evidence is limited.

CONCLUSIONS

While the effectiveness of ONS compared to sham control has been shown in multiple RCTs, the average effect size is modest and may be exaggerated by bias as achieving effective blinding remains a methodological challenge. Further measures to reduce the risk of adverse events and revision surgery are needed.

SYSTEMATIC REVIEW REGISTRATION

this systematic review is an update and expanded work of part of a broader review registered with PROSPERO. Registration No. CRD42012002633.

Pharmacogenetic insights into migraine treatment in children

Pediatric migraine is a disabling condition that can affect the everyday activities and emotional states of children. Due to the multifactorial character of the pathology and the variety of the disease's phenotypes, establishment of an effective treatment is often challenging. Pharmacological treatment is often administered off-label and includes very different drugs, from analgesics to antidepressants. Since interindividual variability in therapy response commonly causes inefficacy and an exacerbation of symptoms, pharmacogenetics may help to decrease the prescription rate of useless or unsafe drugs. If there are many drugs used in migraine, then there are even more candidate or established pharmacogenetic markers that are implicated in clinical profiles. This article presents the current situation regarding the pharmacogenetics of drugs used in pediatric migraine.