Double-blind, randomized, placebo-controlled study to evaluate erenumab-specific central effects: an fMRI study.

OBJECTIVE: Given the findings of central effects of erenumab in the literature, we aimed to conduct a rigorous placebo-controlled, double-blind, randomized study to elucidate whether the observed changes are directly attributable to the drug. METHODS: We recruited 44 patients with migraine, randomly assigning them to either the erenumab 70 mg or the placebo group. 40 patients underwent fMRI scanning using a trigeminal nociceptive paradigm both, pre- and four weeks post-treatment. Participants kept a headache diary throughout the whole study period of two months in total. A clinical response was defined as a ≥30% reduction in headache frequency at follow-up. Details of this study have been preregistered in the open science framework: https://osf.io/ygf3t . RESULTS: Seven participants of the verum group (n=33.33%) and 4 of the placebo group (21.05%) experienced improvements in migraine activity, characterized by a minimum of 30% reduction in monthly headache frequency compared to baseline. The imaging data show an interaction between the verum medication and the response. Whilst numbers were too small for individual analyses (Verum vs. Placebo and Responder vs. Non-Responder), the variance-weighted analysis (Verum vs Placebo, scan before vs after weighted for response) revealed specific decrease in thalamic, opercular and putamen activity. INTERPRETATION: The central effects of erenumab could be reproduced in a placebo randomized design, further confirming its central role in migraine modulation. The mechanism, whether direct or secondary to peripheral mode of action, needs further exploration. It is important to note that the response rate to erenumab 70mg in this study was not as substantial as anticipated in 2019, when this study was planned. This resulted in a too small sample size for a subgroup analysis based on the responder status was associated with both the verum drug and the relative reduction in headache days.

Update in the understanding of new daily persistent headache.

Background Accumulating evidence suggests various specific triggers may lead to new daily persistent headache (NDPH)-like presentations, suggesting that new daily persistent headache is a heterogenous syndrome, and challenging the concept that new daily persistent headache is a primary headache disorder.Method We searched the PubMed database up to August 2022 for keywords including persistent daily headache with both primary and secondary etiologies. We summarized the literature and provided a narrative review of the clinical presentation, diagnostic work-ups, possible pathophysiology, treatment response, and clinical outcomes.Results and conclusion New daily persistent headache is a controversial but clinically important topic. New daily persistent headache is likely not a single entity but a syndrome with different etiologies. The issue with past studies of new daily persistent headache is that patients with different etiologies/subtypes were pooled together. Different studies may investigate distinct subsets of patients, which renders the inter-study comparison, both positive and negative results, difficult. The identification (and removal) of a specific trigger might provide the opportunity for clinical improvement in certain patients, even when the disease has lasted for months or years. Nonetheless, if there is a specific trigger, it remains unknown or unidentified for a great proportion of the patients. We need to continue to study this unique headache population to better understand underlying pathogenesis and, most importantly, to establish effective treatment strategies that hopefully resolve the continuous cycle of pain.

Management of cluster headache: Treatments and their mechanisms.

BACKGROUND: The management of cluster headache is similar to that of other primary headache disorders and can be broadly divided into acute and preventive treatments. Acute treatments for cluster headache are primarily delivered via rapid, non-oral routes (such as inhalation, nasal, or subcutaneous) while preventives include a variety of unrelated treatments such as corticosteroids, verapamil, and galcanezumab. Neuromodulation is becoming an increasingly popular option, both non-invasively such as vagus nerve stimulation when medical treatment is contraindicated or side effects are intolerable, and invasively such as occipital nerve stimulation when medical treatment is ineffective. Clinically, this collection of treatment types provides a range of options for the informed clinician. Scientifically, this collection provides important insights into disease mechanisms. METHODS: Two authors performed independent narrative reviews of the literature on guideline recommendations, clinical trials, real-world data, and mechanistic studies. RESULTS: Cluster headache is treated with acute treatments, bridge treatments, and preventive treatments. Common first-line treatments include subcutaneous sumatriptan and high-flow oxygen as acute treatments, corticosteroids (oral or suboccipital injections) as bridge treatments, and verapamil as a preventive treatment. Some newer acute (non-invasive vagus nerve stimulation) and preventive (galcanezumab) treatments have excellent clinical trial data for episodic cluster headache, while other newer treatments (occipital nerve stimulation) have been specifically tested in treatment-refractory chronic cluster headache. Most treatments are suspected to act on the trigeminovascular system, the autonomic system, or the hypothalamus. CONCLUSIONS: The first-line treatments have not changed in recent years, but new treatments have provided additional options for patients.

Characterization of trigeminal C-fiber reactivity through capsaicin-induced release of calcitonin gene-related peptide.

OBJECTIVE: We hypothesized that the response of trigeminal dermal blood flow (DBF) in the trigeminal system and consecutive expansion of flare response to capsaicin would differ from the somatosensory system (arm). We also investigated whether there are differences between patients with migraine and healthy controls (HC). BACKGROUND: Functional differences between the trigeminal and extracephalic somatosensory systems may partly explain the susceptibility for headaches in patients with migraine. Capsaicin-induced activation of nociceptive C-fibers in the skin is mainly mediated by calcitonin gene-related peptide (CGRP) and induces cutaneous vessel dilatation and flare response. METHODS: Female patients with migraine (n = 38) and age-matched HC (n = 35) underwent DBF measurement at baseline and after topical capsaicin administration using laser speckle imaging. DBF before and after capsaicin stimulation was analyzed over ophthalmic nerve/maxillary nerve/mandibular nerve (V1/V2/V3) dermatomes and the forearm as an extracephalic control. RESULTS: Capsaicin-induced DBF increased more in the trigeminal dermatomes than on the forearm. The V1 dermatome showed a smaller increase of DBF in patients with migraine compared to HC. CONCLUSION: Our results suggest that the trigeminovascular system reacts differently from extracephalic areas, which may explain the trigeminal susceptibility to CGRP-mediated pain attacks. By demonstrating a different reactivity of the V1 dermatome in patients with migraine, our finding suggests that the first trigeminal branch is functionally different from the second and third branches; however, only in patients with migraine.

Cycling multisensory changes in migraine: more than a headache.

PURPOSE OF REVIEW: Research on migraine usually focuses on the headache; however, accumulating evidence suggests that migraine not only changes the somatosensory system for nociception (pain), but also the other modalities of perception, such as visual, auditory or tactile sense. More importantly, the multisensory changes exist beyond the headache (ictal) phase of migraine and show cyclic changes, suggesting a central generator driving the multiple sensory changes across different migraine phases. This review summarizes the latest studies that explored the cyclic sensory changes of migraine. RECENT FINDINGS: Considerable evidence from recent neurophysiological and functional imaging studies suggests that alterations in brain activation start at least 48 h before the migraine headache and outlast the pain itself for 24 h. Several sensory modalities are involved with cyclic changes in sensitivity that peak during the ictal phase. SUMMARY: In many ways, migraine represents more than just vascular-mediated headaches. Migraine alters the propagation of sensory information long before the headache attack starts.

Aura in trigeminal autonomic cephalalgia is probably mediated by comorbid migraine with aura.

OBJECTIVE: The presence of aura is rare in cluster headache, and even rarer in other trigeminal autonomic cephalalgias. We hypothesized that the presence of aura in patients with trigeminal autonomic cephalalgias is frequently an epiphenomenon and mediated by comorbid migraine with aura. METHODS: The study retrospectively reviewed 480 patients with trigeminal autonomic cephalalgia in a tertiary medical center for 10 years. Phenotypes and temporal correlation of aura with headache were analyzed. Trigeminal autonomic cephalalgia patients with aura were further followed up in a structured telephone interview. RESULTS: Seventeen patients with aura (3.5%) were identified from 480 patients with trigeminal autonomic cephalalgia, including nine with cluster headache, one with paroxysmal hemicrania, three with hemicrania continua, and four with probable trigeminal autonomic cephalalgia. Compared to trigeminal autonomic cephalalgia patients without aura, trigeminal autonomic cephalalgia patients with aura were more likely to have a concomitant diagnosis of migraine with aura (odds ratio [OR] = 109.0, 95% CI 30.9-383.0, p < 0.001); whereas the risk of migraine without aura remains similar between both groups (OR = 1.10, 95% CI = 0.14-8.59, p = 0.931). Aura was more frequently accompanied with migraine-like attacks, but not trigeminal autonomic cephalalgia attacks. INTERPRETATION: In most patients with trigeminal autonomic cephalalgia, the presence of aura is mediated by the comorbidity of migraine with aura. Aura directly related to trigeminal autonomic cephalalgia attack may exist but remains rare. Our results suggest that aura may not be involved in the pathophysiology of trigeminal autonomic cephalalgia.

Galcanezumab modulates Capsaicin-induced C-fiber reactivity.

BACKGROUND: The vasodilatory calcitonin-gene related peptide (CGRP) is understood as pivotal mediator in migraine pathophysiology. Blocking CGRP with small molecules or monoclonal antibodies (CGRP-mAb) reduces migraine frequency. However, prescription of CGRP-mAbs is still regulated and possible predictive measures of therapeutic success would be useful. METHODS: Using standardized capsaicin-induced dermal blood flow model, 29 migraine patients underwent a laser speckle imaging measurement before and after administration of galcanezumab. At both sessions dermal blood flow before and after capsaicin stimulation as well as flare size were analyzed over all three trigeminal branches and the volar forearm for extracranial control. Long-term measures were repeated in 14 patients after continuous treatment ranging from 6 to 12 months. RESULTS: Resting dermal blood flow remained unchanged after administration of galcanezumab. Capsaicin-induced dermal blood flow decreased significantly after CGRP-mAb in all tested areas compared to baseline and this was consistent even after 12 months of treatment. However, following galcanezumab administration, the flare size decreased only in the three trigeminal dermatomes, not the arm and was therefore specific for the trigemino-vascular system. None of these two markers distinguished between responders and non-responders. CONCLUSION: CGRP-mAb changed blood flow response to capsaicin stimulation profoundly and this effect did not change over a 12-month application. Neither capsaicin-induced flare nor dermal blood flow can be used as a predictor for treatment efficacy. These data suggest that the mechanism of headache development in migraine is not entirely CGRP-mediated.

Update of New Daily Persistent Headache.

PURPOSE OF REVIEW: The diagnostic criteria of new daily persistent headache (NDPH) have been revised since 2013. The current review focused on the progress of NDPH research over the last few years. RECENT FINDINGS: Various new triggers and different NDPH mimics have been reported. The association with both cephalic and extracephalic pathologies suggests that NDPH is rather a syndrome with more than one disease mechanism. Recent clinical studies confirmed that migrainous headache remained the most prominent phenotype of NDPH, echoing the change of the diagnostic criteria in 2013. Diagnostic workup, including imaging studies, was unremarkable, except serving to exclude secondary etiologies. Studies on treatment options have yet shown promising targets, and randomized clinical trials are still lacking. Multiple mechanisms, both cranial and systemic, may be involved synergically in the generation of NDPH-like headaches. The search for effective treatment options should base on better understanding of disease mechanisms.

Debate: Are cluster headache and migraine distinct headache disorders?

Cluster headache and migraine are regarded as distinct primary headaches. While cluster headache and migraine differ in multiple aspects such as gender-related and headache specific features (e.g., attack duration and frequency), both show clinical similarities in trigger factors (e.g., alcohol) and treatment response (e.g., triptans). Here, we review the similarities and differences in anatomy and pathophysiology that underlie cluster headache and migraine, discuss whether cluster headache and migraine should indeed be considered as two distinct primary headaches, and propose recommendations for future studies. Video recording of the debate held at the 1st International Conference on Advances in Migraine Sciences (ICAMS 2022, Copenhagen, Denmark) is available at https://www.youtube.com/watch?v=uUimmnDVTTE .

Redefining migraine phases - a suggestion based on clinical, physiological, and functional imaging evidence.

Migraine is defined by attacks of headache with a specific length and associated symptoms such as photophobia, phonophobia and nausea. It is long recognized that migraine is more than just the attacks and that migraine should be understood as a cycling brain disorder with at least 4 phases: interictal, preictal, ictal and postictal. However, unlike the pain phase, the other phases are less well defined, which renders studies focusing on these phases susceptible to bias. We herewith review the available clinical, electrophysiological, and neuroimaging data and propose that the preictal phase should be defined as up to 48 hours before the headache attack and the postictal phase as up to 24 hours following the ictal phase. This would allow future studies to specifically investigate these migraine phases and to make study results more comparable.

Cluster headache in Asian populations: Similarities, disparities, and a narrative review of the mechanisms of the chronic subtype.

OBJECTIVE: Headache disorders like migraine show geographic and ethnic differences between Asian and European/North American countries. In cluster headache, these differences are rarely mentioned and discussed. This article aimed to review the characteristics of cluster headache in Asian countries and compare the clinical features to those in European and North American populations. METHODS: We conducted a narrative literature review on the demographics, clinical presentations, and treatments of cluster headache in Asian countries. RESULTS: Patients with cluster headache in Asian populations showed a stronger male predominance compared to European and North American populations. Chronic cluster headache was rare in Asian countries. The clinical presentation of restlessness was not as common in Asian as it was in European and North American countries, and Asian patients with aura were extremely rare. Patients in Asian countries may have a lower circadian rhythmicity of cluster headache and a lower headache load, as demonstrated by lower attack frequencies per day, bout frequencies, and bout durations. CONCLUSIONS: Regional differences in the presentation of cluster headache exist. Greater awareness for cluster headache should be raised in Asian regions, and further studies are warranted to elucidate the mechanisms behind observed differences.

Current understanding of premonitory networks in migraine: A window to attack generation.

AIM: To describe neuronal networks underlying commonly reported migraine premonitory symptoms and to discuss how these might precipitate migraine pain. BACKGROUND: Migraine headache is frequently preceded by a distinct and well characterized premonitory phase including symptoms like yawning, sleep disturbances, alterations in appetite and food intake and hypersensitivity to certain external stimuli. Recent neuroimaging studies strongly suggest the hypothalamus as the key mediator of the premonitory phase and also suggested alterations in hypothalamic networks as a mechanism of migraine attack generation. When looking at the vast evidence from basic research within the last decades, hypothalamic and thalamic networks are most likely to integrate peripheral influences with central mechanisms, facilitating the precipitation of migraine headaches. These networks include sleep, feeding and stress modulating centers within the hypothalamus, thalamic pathways and brainstem centers closely involved in trigeminal pain processing such as the spinal trigeminal nucleus and the rostral ventromedial medulla, all of which are closely interconnected. CONCLUSION: Taken together, these networks represent the pathophysiological basis for migraine premonitory symptoms as well as a possible integration site of peripheral so-called "triggers" with central attack facilitating processes.

Risk factors and psychological impact of syncope in migraine patients.

BACKGROUND: Migraine is associated with syncope. We investigated risk factors for syncope and burden of syncope in migraine patients. METHODS: Participants were recruited from a headache clinic. All participants provided information on lifestyle, co-morbidity, syncope, headache and suicide, and completed the MIDAS and HADS questionnaires. Genetic data were available for a subset of participants. Risk of syncope in relation to participant's characteristics and migraine susceptibility loci, and risks of psychological disorders associated with syncope, were calculated using logistic regression. RESULTS: Underweight, regular tea intake, diabetes mellitus, and migraine with aura were associated with increased syncope risks, with adjusted ORs of 1.76 (95% CI 1.03-3.03), 1.84 (95% CI 1.22-2.79), 4.70 (95% CI 1.58-13.95), and 1.78 (95% CI 1.03-3.10), respectively. Preliminary results showed that rs11172113 in LRP1 was associated with syncope risks. Comorbid syncope in migraine patients was associated with increased risks of depression (OR 1.95, 95% CI 1.18-3.22) and suicide attempt (OR 2.85, 95% CI 1.48-5.48). CONCLUSION: Our study showed the potential roles of vascular risk factors in the association between migraine and syncope. Modifiable risk factors for syncope in patients with migraine include body mass index and tea intake. The debilitating psychological impact of co-morbid syncope in migraine patients warrants clinical attention of treating physicians.

Migraine and incidence of ischemic stroke: A nationwide population-based study.

Background The association between migraine and the incidence of ischemic stroke varies in different subgroups of patients. We aimed to clarify this association using a population-based database. Method A nationwide cohort study was conducted using data from the Taiwan National Health Insurance Research Database. Two cohorts were extracted: a neurologist-diagnosed migraine cohort, and a non-headache, propensity score-matched comparison cohort. All participants were enrolled in this study between 2005 and 2009, and were followed through the end of 2010, death, or the occurrence of ischemic stroke. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were calculated with a Cox proportional hazards model to compare the between-group risks. Results Both cohorts ( n = 119,017 each) were followed for a mean period of 3.6 ± 1.3 years. A total of 744 migraine patients (429,741 person-years) and 617 matched comparison individuals (436,141 person-years) developed ischemic stroke during the research period. Compared to the comparison cohort, patients with migraine were at an increased risk of ischemic stroke (aHR: 1.24, 95% CI: 1.12-1.38, p < 0.001). Subgroup analysis by age and sex revealed the highest risk in women aged ≤ 45 years (aHR: 3.44, 95% CI: 2.20-5.39, p < 0.001), especially among those with migraine with aura (aHR: 4.58, 95% CI: 2.45 - 8.56, p < 0.001). A trend for increased stroke risk was observed in men aged ≤ 45 years (aHR: 1.54, 95% CI: 0.96-2.48, p = 0.075). Conclusion Migraine is associated with an increased risk of ischemic stroke, especially in younger (age ≤ 45 years) women with migraine with aura. The trend toward ischemic stroke in younger men merits further exploration.

Association between migraine and risk of venous thromboembolism: A nationwide cohort study.

BACKGROUND: -The link between arterial thromboembolism and migraine is well-documented; however, few studies investigated the link between venous thromboembolism (VTE) and migraine. We aimed to evaluate the association between migraine and VTE and to examine whether demographics or comorbid risk factors modulate VTE development. METHODS: -We conducted a cohort study accessing a nationwide claims-based database with an adult cohort of 102,159 neurologist-diagnosed migraine patients, and 102,159 nonheadache comparison subjects, matched on sex and propensity score for the diagnosis of migraine. Both cohorts were followed until the end of 2010, death, or VTE development. Adjusted hazard ratios (aHRs) and 95% confidence intervals (CIs) were calculated based on Cox proportional hazards regression analyses and compared between the two groups. RESULTS: -During a mean follow-up period of 4.2 years, VTE developed in 226 patients (460,047 person-years) in the migraine cohort and in 203 subjects (462,401 person-years) in the comparison cohort. Overall, likelihood of VTE for the migraine cohort did not differ from that in the comparison cohort (aHR 1.12; 95% CI, 0.92-1.35; P = .251). However, subgroup analysis by migraine subtypes (P = .004 for interaction) revealed an elevated risk of VTE in patients with migraine with aura (aHR 2.42; 95% CI, 1.40-4.19; P = .002), but not in those with migraine without aura. The association was not altered in subsequent subgroup analyses and sensitivity analyses. Conclusions Risk of VTE development is elevated specifically in patients diagnosed with migraine with aura. This association suggests a linked disease mechanism and warrants further exploration.