Citations

Objective To provide clinically relevant insights on the identification of the muscles and techniques involved in the safe and effective use of onabotulinumtoxinA for chronic migraine prophylaxis. Background Although guidance on the use of onabotulinumtoxinA for chronic migraine is available, based on the Phase III Research Evaluating Migraine Prophylaxis Therapy (PREEMPT) clinical program, clinical experience has shown that insufficient understanding of the anatomy and function of the head and neck muscles may lead to undesirable outcomes and suboptimal efficacy. Design/Methods Each muscle involved in the standardized PREEMPT injection paradigm is reviewed with a thorough description of each muscle's anatomy (ie, muscle description and location, innervation, vascular supply) and function. Key insights based on clinical experience are also provided to help improve outcomes. Results The identification of the muscles in the PREEMPT injection paradigm should be based on each patient's unique anatomy and injections should be administered using the advised techniques. A thorough examination of the patient prior to treatment is also critical to determine if any preexisting conditions may increase the risk for unwanted outcomes and appropriate expectations should be communicated. Conclusions Thorough knowledge of the functional anatomy of the muscles involved in the standardized PREEMPT injection paradigm is critical to achieve the efficacy and safety observed in clinical trials. In addition, it is important to assess a patient's baseline condition to anticipate the risk for unwanted outcomes that may result from treatment.

Background Stress is the most commonly reported migraine trigger. Dynorphin, an endogenous opioid peptide acting preferentially at kappa opioid receptors (KORs), is a key mediator of stress responses. The aim of this study was to use an injury-free rat model of functional cephalic pain with features of migraine and medication overuse headache (MOH) to test the possible preventive benefit of KOR blockade on stress-induced cephalic pain. Methods Following sumatriptan priming to model MOH, rats were hyper-responsive to environmental stress, demonstrating delayed cephalic and extracephalic allodynia and increased levels of CGRP in the jugular blood, consistent with commonly observed clinical outcomes during migraine. Nor-binaltorphimine (nor-BNI), a long-acting KOR antagonist or CYM51317, a novel short-acting KOR antagonist, were given systemically either during sumatriptan priming or immediately before environmental stress challenge. The effects of KOR blockade in the amygdala on stress-induced allodynia was determined by administration of nor-BNI into the right or left central nucleus of the amygdala (CeA). Results KOR blockade prevented both stress-induced allodynia and increased plasma CGRP. Stress increased dynorphin content and phosphorylated KOR in both the left and right CeA in sumatriptan-primed rats. However, KOR blockade only in the right CeA prevented stress-induced cephalic allodynia as well as extracephalic allodynia, measured in either the right or left hindpaws. U69,593, a KOR agonist, given into the right, but not the left, CeA, produced allodynia selectively in sumatriptan-primed rats. Both stress and U69,593-induced allodynia were prevented by right CeA U0126, a mitogen-activated protein kinase inhibitor, presumably acting downstream of KOR. Conclusions Our data reveal a novel lateralized KOR circuit that mediated stress-induced cutaneous allodynia and increased plasma CGRP in an injury-free model of functional cephalic pain with features of migraine and medication overuse headache. Selective, small molecule, orally available, and reversible KOR antagonists are currently in development and may represent a novel class of preventive therapeutics for migraine.

Objectives To survey experts in Headache Medicine on their opinions regarding appropriate non‐inferiority margins for outcomes commonly used in migraine research. Methods Members of the American Headache Society and the Canadian Headache Society were invited to participate in the Non‐Inferiority Margins in Migraine Research (NIMM) survey. Adult and child neurologists with expertise in Headache Medicine were eligible to participate. The survey had a multiple choice format and comprised questions on respondent characteristics, eligibility, as well as expert opinion on non‐inferiority margins for outcomes commonly used in trials of both prophylactic and acute interventions for migraine. Results Ninety‐nine eligible respondents completed the survey. Most respondents were adult neurologists (84.9%) and 74% reported practicing in the USA. The following were the most commonly selected non‐inferiority margins: (1) change in monthly migraine attacks comparing baseline to the treatment period: 1 attack (39.4% selecting), (2) change in monthly migraine days comparing baseline to the treatment period: 1 day (44.4%), (3) change in average migraine intensity on a 4‐point scale comparing baseline to the treatment period: 1.0 (31.3%), (4) percentage of participants who are pain‐free 2 hours after the intervention: 5% (41.4%), (5) percentage of participants who have a migraine recurrence within 48 hours of treatment: 5% (42.4%), and (6) percentage of participants with sustained pain freedom: 5% (42.4%). Conclusions The results of the NIMM survey describe the opinions of a group of experts on appropriate non‐inferiority margins for outcomes commonly used in migraine clinical trials. There was significant variability in responses and lack of consensus on the choice of non‐inferiority margins. The survey did not incorporate the patient perspective and was not validated prior to distribution. Further work in this area is required in order to explore how to incorporate clinical considerations into the selection of non‐inferiority margins for migraine research.

Objective The interplay between neuronal innervation and other cell types underlies the physiological functions of the dura mater and contributes to pathophysiological conditions such as migraine. We characterized the extensive, but understudied, non-arterial diffuse dural innervation (DDI) of the rat and Rhesus monkey. Methods We used a comprehensive integrated multi-molecular immunofluorescence labeling strategy to extensively profile the rat DDI and to a lesser extent that of the Rhesus monkey. Results The DDI was distributed across a dense, pervasive capillary network and included free nerve endings of peptidergic CGRP-expressing C fibers that were closely intertwined with noradrenergic (NA) sympathetic fibers and thin-caliber nonpeptidergic “C/Aδ” fibers. These newly identified C/Aδ fibers were unmyelinated, like C fibers, but expressed NF200, usually indicative of Aδ fibers, and uniquely co-labeled for the CGRP co-receptor, RAMP1. Slightly-larger caliber NF200-positive fibers co-labeled for myelin basic protein (MBP) and terminated as unbranched corpuscular endings. The DDI peptidergic fibers co-labeled for the lectin IB4 and expressed presumably excitatory α1-adrenergic receptors, as well as inhibitory 5HT1D receptors and the delta opioid receptor (δOR), but rarely the mu opioid receptor (µOR). Labeling for P2X3, TRPV1, TRPA1, and parasympathetic markers was not observed in the DDI. Interpretation These results suggest potential functional interactions, wherein peptidergic DDI fibers may be activated by stress-related sympathetic activity, resulting in CGRP release that could be detected in the circulation. CGRP may also activate nonpeptidergic C/Aδ fibers that are likely mechanosensitive or polymodal, leading to activation of post-synaptic pain transmission circuits. The distribution of α1-adrenergic receptors, RAMP1, and the unique expression of the δOR on CGRP-expressing DDI fibers suggest strategies for functional modulation and application to therapy.

Background Migraine prevention guidelines recommend oral prophylactic medications for patients with frequent headache. This study examined oral migraine preventive medication (OMPM) treatment patterns by evaluating medication persistence, switching, and re-initiation in patients with chronic migraine (CM). Methods A retrospective US claims analysis (Truven Health MarketScan® Databases) evaluated patients ≥18 years old diagnosed with CM who had initiated an OMPM between 1 January, 2008 and 30 September, 2012. Treatment persistence was measured at six and 12 months’ follow-up. Time-to-discontinuation was assessed for each OMPM and compared using Cox regression models. Among those who discontinued, the proportion that switched OMPMs within 60 days or re-initiated treatment between 61 to 365 days, and their associated persistence rates, were also assessed. Results A total of 8707 patients met the inclusion/exclusion criteria. Persistence to the initial OMPM was 25% at six months and 14% at 12 months. Based on Kaplan-Meier curves, a sharp decline of patients discontinuing was observed by 30 days, and approximately half discontinued by 60 days. Similar trends in time-to-discontinuation were seen following the second or third OMPM. Amitriptyline, gabapentin, and nortriptyline had significantly higher likelihood of non-persistence compared with topiramate. Among patients who discontinued, 23% switched to another prophylactic and 41% re-initiated therapy within one year. Among patients who switched, persistence was between 10 to 13% and among re-initiated patients, persistence was between 4 to 8% at 12 months. Conclusions Persistence to OMPMs is poor at six months and declines further by 12 months. Switching between OMPMs is common, but results indicate that persistence worsens as patients cycle through various OMPMs.

Efficient eye movements provide a physical foundation for proficient reading skills. We investigated the effect of in-school saccadic training on reading performance. In this cross-over design, study participants (n = 327, 165 males; mean age [SD]: 7 y 6 mo [1y 1 mo]) were randomized into treatment and control groups, who then underwent eighteen 20-minute training sessions over 5 weeks using King-Devick Reading Acceleration Program Software. Pre- and posttreatment reading assessments included fluency, comprehension, and rapid number naming performance. The treatment group had significantly greater improvement than the control group in fluency (6.2% vs 3.6%, P = .0277) and comprehension (7.5% vs 1.5%, P = .0002). The high-needs student group significantly improved in fluency ( P < .001) and comprehension ( P < .001). We hypothesize these improvements to be attributed to the repetitive practice of reading-related eye movements, shifting visuospatial attention, and visual processing. Consideration should be given to teaching the physical act of reading within the early education curriculum.

AbstractMigraine is one of the world's most common neurological disorders. Current acute migraine treatments have suboptimal efficacy, and new therapeutic options are needed. Approaches targeting calcitonin gene related peptide (CGRP) signaling are clinically effective, but small molecule antagonists have not been advanced because of toxicity. In this study, we explored the axonal growth/specification collapsin response mediator protein 2 (CRMP2) as a novel “druggable” target for inhibiting CGRP release and for potential relevance for treatment of migraine pain. Collapsin response mediator protein 2 has been demonstrated to regulate N-type voltage-gated Ca2+channel activity and Ca2+-dependent CGRP release in sensory neurons. The coexpression of CRMP2 with N-type voltage-gated Ca2+channel and CGRP in trigeminal ganglia (TGs) sensory neurons suggested the possibility of a novel approach to regulate CGRP release in the trigeminal system. Screening protocols surprisingly revealed that (S)-lacosamide ((S)-LCM), an inactive analog of the clinically approved small molecule antiepileptic drug (R)-lacosamide (Vimpat), inhibited CRMP2 phosphorylation by cyclin-dependent kinase 5 in rat TG slices and decreased depolarization-evoked Ca2+influx in TG cells in culture. (S)-LCM significantly blocked capsaicin-evoked CGRP release from dural nerve terminals in the rat in ex vivo cranial cup preparation. Additionally, cephalic and extracephalic cutaneous allodynia induced in rats by activation of dural nociceptors with a cocktail of inflammatory mediators, was inhibited by oral administration of (S)-LCM. The confirmation of CRMP2 as an upstream mediator of CGRP release, together with the brain penetrance of this molecule suggests (S)-LCM as a potential therapy for acute migraine.

AbstractMigraine has complex relationships with disorders of the heart, the cardiovasculature and the cerebrovasculature. The purpose of this review was to summarize data regarding the relationship of migraine with structural cardiac disease, cardiovascular disease and stroke. There are low‐quality and/or conflicting data regarding a possible association between migraine with patent foramen ovale and other sources of right‐to‐left shunt. If these associations exist, migraine with aura, in contrast to migraine without aura, would likely account for the comorbidity. Although low‐quality evidence suggested that patent foramen ovale closure results in improved migraine patterns, higher‐quality evidence from prospective clinical trials of patent foramen ovale closure failed to achieve their primary end‐points. There are conflicting data regarding an increased risk of cardiovascular disease in people with migraine. Overall, data suggest that migraine with aura is probably associated with an increased risk for cardiovascular disease. Consistently, studies have shown migraine with aura to be associated with an increased risk for ischemic stroke. The explanation for the comorbidity between migraine with aura and cardiovascular and cerebrovascular diseases has yet to be adequately defined. Potential causal relationships and shared underlying risk factors are discussed. Migraine with aura is associated with an increased risk for ischemic stroke. Migraine with aura might be associated with an increased risk for cardiovascular disease and an increased likelihood for structural cardiac disease, such as patent foramen ovale. Further investigations will define the existence and nature of the relationship between migraine with aura and these disorders.