Same-Day Bilateral Decubitus CT Myelography for Detecting CSF-Venous Fistulas in Spontaneous Intracranial Hypotension

Lateral decubitus CT myelography is a sensitive technique for detecting CSF-venous fistulas in patients with spontaneous intracranial hypotension. It might be necessary to perform bilateral studies to locate a fistula. We report on the feasibility of obtaining diagnostic-quality bilateral decubitus CT myelography in a single session, avoiding the need to schedule separate examinations for the left and right sides on different days.

Visual snow syndrome: a comparison between an Italian and British population

BACKGROUND AND PURPOSE

Visual snow manifests as a pan-field, dynamic visual disturbance described as continuous television static-like tiny flickering dots. Current diagnostic criteria further require at least two additional symptoms for visual snow syndrome (VSS) from: palinopsia (afterimages and trailing); entoptic phenomena (floaters, blue field entoptic phenomenon, photopsia, self-light of the eye); photophobia and nyctalopia. Our objective was to compare the phenotype of VSS in an Italian and British population.

METHODS

Patients with VSS were characterized clinically using the current criteria. An online survey was prepared in collaboration with the patient group Eye-on-Vision. Patients were directed to the site if they contacted us by email asking to be involved in research. After data collection, we compared the phenotypic characteristics of a subgroup of British versus Italian patients taking part in the survey. As we expected more responses from the UK, we matched 100 UK patients for gender and age with our Italian cohort.

RESULTS

Patients were enrolled from the UK (n = 100) and Italy (n = 100). The populations had similar demography. After multiple correction testing there were no differences in VSS features between the two groups. The same was true for the prevalence of migraine and previous use of recreational drugs.

CONCLUSION

This is the first study comparing the phenotype of VSS between two distinct populations. Our findings suggest that the visual snow phenotype, as well as migraine comorbidity, is similar across the two groups.

Efficacy of galcanezumab in patients with episodic migraine and a history of preventive treatment failure: results from two global randomized clinical trials

BACKGROUND AND PURPOSE

The efficacy of galcanezumab, a monoclonal antibody for migraine prevention, has been demonstrated in two pivotal trials in patients with episodic migraine.

METHODS

EVOLVE-1 and EVOLVE-2 were identical phase 3, randomized, double-blind, placebo-controlled studies in patients with episodic migraine. Mean migraine headache days per month at baseline was 9. Patients were randomized 2:1:1 to monthly injections of placebo, galcanezumab 120 mg/240 mg during the 6-month double-blind treatment period. Key efficacy outcomes were assessed in subgroups amongst patients for whom, previously, for efficacy and/or safety/tolerability reasons (i) one or more (≥1) preventives failed, (ii) two or more (≥2) preventives failed and (iii) preventives were never used, or used but not failed (no prior failure).

RESULTS

In an integrated analysis of EVOLVE studies, galcanezumab 120 mg/240 mg versus placebo led to larger overall mean (SE) reductions in monthly migraine headache days across 6 months in patients with prior preventive failures (P < 0.001): ≥1 failure: 120 mg: -4.0 (0.4); 240 mg: -4.2 (0.5); placebo: -1.3 (0.4); ≥2 failures: 120 mg: -3.1 (0.7); 240 mg: -3.8 (0.8); placebo: -0.5 (0.6). Similar results were observed amongst patients with no prior failure, but the placebo response was larger: 120 mg: -4.7 (0.2); 240 mg: -4.5 (0.2); placebo: -3.0 (0.2) (P < 0.001 versus placebo). Significant improvements were observed with galcanezumab versus placebo for ≥50% and ≥75% reduction in monthly migraine headache days.

CONCLUSION

In patients with episodic migraine treated with galcanezumab, those with ≥1 or ≥2 prior preventive failures had significantly larger improvements, versus placebo, in efficacy outcomes. Similar results were observed in patients with no prior failure, with a larger placebo response.

Trigeminal autonomic cephalalgias presenting in a multidisciplinary tertiary orofacial pain clinic

Abstract

Orofacial pain may have a variety of causes and offers a significant clinical challenge for its diagnosis and management.

Objective

To assess the headache disorders presenting in a tertiary multidisciplinary orofacial pain clinic, after dental causes have been excluded.

Methods

Clinic letters from the initial consultation and subsequent follow up reviews of the 142 patients, who were seen in the tertiary Multidisciplinary Orofacial Pain clinic between January 2015 until January 2018 were reviewed as a clinical audit.

Results

The most common diagnoses were possible trigeminal autonomic cephalalgia (n = 62, 44%), migraine (n = 38, 27%) and painful post-traumatic trigeminal neuropathy (n = 17, 12%). The most common trigeminal autonomic cephalalgia diagnosis was hemicrania continua (n = 13, 9%), which is higher than the reported prevalence in neurology and headache clinics.

Conclusion

This study demonstrates the importance of a multidisciplinary approach to diagnosing complex orofacial pain patients and the importance of awareness of primary headache disorders, in particular trigeminal autonomic cephalalgias, thereby reducing unnecessary diagnostic delays or procedures.

THUR 084 Cranial autonomic symptoms in cluster headache induced by nitroglycerin

Introduction

Cluster headache (CH) is characterised by attacks of unilateral excruciating headache, ipsilateral cranial autonomic symptoms (CAS) and/or agitation. Studying of CAS can further our understanding of CH pathophysiology, but is limited by the episodic nature of the disease. Nitroglycerin (NTG) is known to induce CH. The aim of this study is to characterise CAS induced by NTG.

Methods

CH patients received intravenous NTG 0.5 mcg/kg/min over 20 min. CAS and headache phenotype were recorded. The study was approved by the NHS Research Ethics Committee.

Results

Twenty-three patients participated: 83% male and 61% episodic cluster headache. The most common spontaneous CAS reported were lacrimation, nasal congestion and conjunctival injection. Agitation was reported in 96%. Nitroglycerin induced ipsilateral CAS in 91% of the patients, with 74% with ipsilateral pain. Most commonly induced CAS were nasal congestion, lacrimation and periorbital swelling. Agitation was reported in 61%. The majority of the CAS (80%) induced by NTG presented before the onset of severe pain.

Conclusion

We demonstrate that NTG effectively triggers ipsilateral cranial autonomic symptoms in CH patients and that they often present in a phase before the onset of pain reflecting the underlying pathways during a cluster headache attack.

Flunarizine in migraine-related headache prevention: results from 200 patients treated in the UK

BACKGROUND AND PURPOSE

For over 20 years, as a group we have been using flunarizine in primary headache disorders. Flunarizine is widely used in Europe, but not licensed in the UK. In September 2014, the National Institute for Clinical Excellence published supportive guidelines for flunarizine use in migraine, based on randomized controlled evidence that it is as effective as propranolol and topiramate in adults.

METHODS

We reviewed a cohort of adult patients (n = 200) treated with flunarizine from our practice. The clinical information of these patients, i.e. diagnosis, dose, efficacy, side effects and duration of treatment, was collected.

RESULTS

The most common indication for flunarizine use was chronic migraine, followed by migraine with aura, sporadic hemiplegic migraine, familial hemiplegic migraine and new daily persistent headache with migrainous features. Flunarizine was generally effective, with only 24% (n = 47) of patients reporting no clinical effect. The most common dose used was 10 mg per day. Duration of treatment information was available for 39% (n = 78) of patients. Of these patients, 64% (n = 50) continued treatment for more than 1 year. Doses up to 15 mg were generally well tolerated, with only 10.5% (n = 21) of patients stopping treatment due to adverse effects. The most common adverse events were tiredness, mood change and weight gain.

CONCLUSION

The data provide supportive evidence from tertiary headache practice in the UK for the use of flunarizine in migraine. The data encourages development of future guidance regarding flunarizine use in headache centres in countries where its use is not routine.

Premonitory Symptoms of Migraine in Childhood and Adolescence

Purpose of Review

Premonitory symptoms in migraine; symptoms occurring before the onset of migraine pain or aura, are an increasingly recognised area of interest within headache research. It has been recently documented in the literature that these symptoms also occur in children and adolescents, with a comparable phenotype to adults. This review discusses the wide presentation of premonitory symptoms in migraine in children and adolescents, and the importance of understanding how these early symptoms are mediated in order to ensure that targeted abortive therapies are developed in the future. Recognition of these symptoms by parents, guardians, teachers and carers is of importance in ensuring early and effective attack treatment.

Recent Findings

A previous clinic-based questionnaire study in 103 children found a prevalence of premonitory symptoms in paediatric migraine of 67%, with a mean number of reported symptoms of two. A recent study found that in a clinic population of 100 children or adolescents with a migraine diagnosis who were preselected as having at least one premonitory symptom associated with their attacks, two or more premonitory symptoms were reported by 85% of patients. The most common symptoms were fatigue, mood change and neck stiffness.

Summary

Although the population prevalence of premonitory symptoms in migraine within the paediatric population, or their ability to predict accurately the onset of an impending headache cannot be deduced from the retrospective studies performed to date, premonitory symptoms occur in children as young as 18 months old. Understanding the biological basis of these, and their heterogeneous phenotype may help future targeted therapeutic research, helping the development of drugs that act before the onset of pain, limiting the morbidity associated with the migraine attack.

Abnormal Blink Reflex Studies in a Patient With Supraorbital Neuralgia

A 44-year-old female with gabapentin-responsive supraorbital neuralgia is presented. She had pre- and post-treatment nociceptive-specific blink reflexes carried out which tracked the good clinical outcome from treatment. The results of the electrophysiological testing imply some central component to the pathophysiology of supra-orbital neuralgia.

Characterising the premonitory stage of migraine in children: a clinic-based study of 100 patients in a specialist headache service

Background

The premonitory stage of migraine attacks, when symptomatology outside of pain can manifest hours to days before the onset of the headache, is well recognised. Such symptoms have been reported in adults in a number of studies, and have value in predicting an impending headache. These symptoms have not been extensively studied in children. We aimed to characterise which, if any, of these symptoms are reported in children seen within a Specialist Headache Service.

Methods

We reviewed clinic letters from the initial consultation of children and adolescents seen within the Specialist Headache Service at Great Ormond Street Hospital between 1999 and 2015 with migraine in whom we had prospectively assessed clinical phenotype data. We randomly selected 100 cases with at least one premonitory symptom recorded in the letter. For these patients, the age at headache onset, presence of family history of headache, headache diagnosis, presence of episodic syndromes which may be associated with headache, developmental milestones, gestation at birth, mode of delivery and presence of premonitory symptoms occurring before or during headache were recorded.

Results

Of the 100 patients selected, 65 % were female. The age range of the patients was 18 months to 15 years at the time of headache onset. The most common diagnosis was chronic migraine in 58 %, followed by episodic migraine (29 %), New Daily Persistent Headache with migrainous features (8 %) and hemiplegic migraine (5 %). A history of infantile colic was noted in 31 % and was the most common childhood episodic syndrome associated with migraine. The most common premonitory symptoms recorded were fatigue, mood change and neck stiffness. The commonest number of reported premonitory symptoms was two.

Conclusion

Premonitory symptoms associated with migraine are reported in children as young as 18 months, with an overall clinical phenotype comparable to adults. Better documentation of this stage will aid parents and clinicians to better understand the phenotype of attacks, better recognise migraine and thus initiate appropriate management. Larger studies with a broader base are warranted to understand the extent and implications of these symptoms for childhood and adolescent migraine.

Variability of the characteristics of a migraine attack within patients

Background

Migraine attacks may present different features in different patients and also within the same patient. The percentage of patients reporting stereotyped attacks and those reporting attacks with different phenotypes has not been the object of specific investigations.

Objective

The objective of this article is to evaluate the percentage of migraine patients reporting the same characteristics, in terms of phenotype and response to symptomatic medications on three consecutive migraine attacks.

Methods

Thirty patients with migraine without aura prospectively recorded the features of three consecutive attacks in a headache diary. Characteristics recorded were: pain intensity, presence of nausea, vomiting, photophobia, phonophophia, osmophobia, allodynia, cranial autonomic symptoms (at least one), and premonitory symptoms. Patients were allowed to take frovatriptan as symptomatic medication, whose efficacy was evaluated as the two hours pain-free status.

Results

None of the patients presented identical characteristics on the three studied attacks. This was still the case if we reduced the number of variables evaluated from 11 to seven of the eight core features indicated by the ICHD. Considering just six variables: unilaterality and quality of pain, presence/absence of nausea, vomiting, photophobia and phonophobia, only two patients (6%) had identical features on three consecutive attacks. With respect to the response to frovatriptan, 39% of patients had the same response, either positive (i.e. pain free after two hours) or negative (i.e. not pain free after two hours) on three consecutive attacks.

Conclusion

Migraine attacks show a high variability not just among patients, but also within the same patient. Our data indicate that stereotypy of attacks is uncommon, and reinforces the underlying logic of the current operational classification system.

Paroxysmal Hemicrania in a Family

Paroxysmal hemicrania (PH) is a trigeminal autonomic cephalgia, characterised by unilateral attacks responsive to indomethacin. There are no published reports of a family history in PH. We report a mother and daughter both with PH. The daughter and her sister also had migraine.

Dopamine and Migraine: Biology and Clinical Implications

In the last 30 years dopamine has been considered as playing a role in the pathogenesis of migraine. The literature indicates that migraineurs are hypersensitive to dopamine agonists with respect to some of the premonitory symptoms of migraine such as nausea and yawning. There are various nonspecific dopamine D2 receptor antagonists that show good clinical efficacy in migraine, and also a number of polymorphisms of dopaminergic genes related to migraine. Animal studies have also shown that dopamine receptors are present in the trigeminovascular system, the area believed to be involved in headache pain, and neuronal firing here is reduced by dopamine agonists. There appears to be little effect of dopamine on peripheral trigeminal afferents. We assess some of the limitations of the clinical studies with regard to the therapeutics, and those found in the studies that discovered differences in genetic polymorphisms in migraine, and consider the implications of this on a dopaminergic hypothesis of migraine.

Topiramate Inhibits Trigeminovascular Neurons in the Cat

To facilitate understanding the action of antimigraine preventives the effect of topiramate on trigeminocervical activation in the cat was examined. Animals ( n = 7) were anaesthetized and physiologically monitored. The superior sagittal sinus (SSS) was stimulated to produce a model of trigeminovascular nociceptive activation. Cumulative dose-response curves were constructed for the effect of topiramate at doses of 3, 5, 10, 30 and 50 mg/kg on SSS-evoked firing of trigeminocervical neurons. Topiramate reduced SSS evoked firing in a dose-dependent fashion. The maximum effect was seen over 30 min for the cohort taken together. At 3 mg/kg firing was reduced by 36 ± 13% (mean ± SEM) after 15 min. At 5 and 50 mg/kg firing was reduced by 59 ± 6% and 65 ± 14%, respectively, after 30 min. Inhibition of the trigeminocervical complex directly, or neurons that modulate sensory input, are plausible mechanisms for the action of preventives in migraine.

Intravital Microscopy on a Closed Cranial Window in Mice: A Model to Study Trigeminovascular Mechanisms Involved in Migraine

The purpose of the study was to develop a mouse model to study trigeminovascular mechanisms using intravital microscopy on a closed cranial window. In addition, we studied exogenous and endogenous calcitonin gene-related peptide (CGRP)-mediated vasodilation in dural arteries. Arteries in C57BL/6Jico mice were constricted with endothelin-1, which reduced the baseline diameter by 65-75%. Subsequently, vasodilation was induced by α-CGRP, capsaicin or transcranial electrical stimulation of perivascular trigeminal nerves in the absence or presence of different concentrations of BIBN4096BS or sumatriptan. Both α-CGRP and capsaicin induced vasodilation in preconstricted arteries. Transcranial electrical stimulation also induced current-dependent relaxation of dural arteries with 100 μA producing maximal dilation in the control group. BIBN4096BS blocked the responses evoked by ä-CGRP and capsaicin, as well as electrical stimulation, whereas sumatriptan attenuated only vasodilation induced by electrical stimulation. This model is likely to prove useful in dissecting elements of the trigeminovascular system and for exploring pathophysiological aspects of migraine, especially in future studies using transgenic mice with mutations relevant to those observed in patients with migraine.

Deep Brain Stimulation for Intractable Chronic Cluster Headache: Proposals for Patient Selection

Cluster headache is the most severe of the primary headaches. Positron emission tomography and functional MRI studies have shown that the ipsilateral posterior hypothalamus is activated during cluster headache attacks and is structurally asymmetric in these patients. These changes are highly specific for the condition and suggest that the cluster headache generator may be located in that brain area; they further suggest that electrical stimulation of that region might produce clinical improvement in chronic cluster headache sufferers refractory to medical therapy. In five patients with severe intractable chronic cluster headache, hypothalamic electrical stimulation produced complete and long-term pain relief with no relevant side-effects. We therefore consider it essential to propose criteria for selecting chronic cluster headache patients for hypothalamic deep brain stimulation before this procedure is undertaken at other academic medical centres.

Evaluation and Proposal for Optimization of Neurophysiological Tests In Migraine: Part 2—Neuroimaging and The Nitroglycerin Test

Neuroimaging methods have been widely used in headache and migraine research. They have provided invaluable information on brain perfusion, metabolism and structure during and outside of migraine attacks, contributing to an improved understanding of the pathophysiology of the disorder. Human models of migraine attacks are indispensable tools in pathophysiological and therapeutic research. This review of neuroimaging methods and the attack-provoking nitroglycerin test is part an initiative by a task force within the EUROHEAD project (EU Strep LSHM-CT-2004-5044837-Workpackage 9) with the objective of critically evaluating neurophysiological tests used in migraine. The first part, presented in a companion paper, is devoted to electrophysiological methods, this second part to neuroimaging methods such as functional magnetic resonance imaging, positron emission tomography and voxel-based morphometry, as well as the nitroglycerin test. For each of these methods, we summarize the results, analyse the methodological limitations and propose recommendations for improved methodology and standardization of research protocols.

Familial SUNCT

Short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT) is a rare type of primary headache. In this report we describe the occurrence of SUNCT in a family. Unfortunately, one of the siblings was already dead. However, clear and detailed information from close relatives and her general practitioner confirmed the diagnosis of SUNCT. It is likely that genetic factors contribute to all types of trigeminal autonomic cephalalgias.

Diffusion- and Perfusion-Weighted MR Imaging in Persistent Migrainous visual Disturbances

Pathological changes on diffusion-weighted MR scans had been described in hemiplegic migraine and perfusion changes had been demonstrated in typical migraine aura with radio-isotope studies and, more recently, MR perfusion imaging. However, there is relatively little knowledge of the pathophysiology of long-lasting migraine aura and its possibly variant phenotype, visual snow. Our aim was to investigate with advanced MR techniques whether patients with long-lasting visual disturbance showed regional alterations in cerebral water diffusion and perfusion. We have studied four patients using MR perfusion and MR diffusion imaging. Two patients had typical visual aura and two had a primary persistent visual disturbance (visual snow phenomenon). All patients had normal conventional structural MR imaging. MR diffusion-weighted images were acquired with a b-value of up to 1000 s/mm2. From the diffusion weighted images we generated maps of apparent diffusion coefficient (ADC), which were inspected visually and used for ADC measurements of predefined regions of interest, which included the visual, frontal, insular and temporal cortices. MR perfusion imaging was performed using a bolus tracking technique with dynamic susceptibility-weighted images. Colour coded maps of relative cerebral blood volume, mean transit time and bolus arrival time were generated, as well as time-signal intensity curves over the anterior, middle and posterior cerebral artery territories. The maps of the ADC and above perfusion parameters appeared symmetrical in all patients with no evidence of decreased water diffusion or cerebral perfusion in the occipital regions, or elsewhere. There was no statistically significant difference between the ADC measurements of the primary visual cortices and other cortical regions. Our findings suggest that regional changes in cerebral water diffusion and perfusion do not play an important part in the pathophysiology of persistent migraine aura or primary persistent visual disturbance.

Double-Blind Clinical Trials of Oral Triptans Vs Other Classes of Acute Migraine Medication — A Review

Although the migraine clinical trials literature is enormous, we identified only nine published double-blind studies which compare an oral triptan with a non-triptan acute treatment. Of the nine comparative trials that met inclusion criteria for this review, six compared sumatriptan with other drugs, zolmitriptan was studied in two trials and eletriptan in one trial. In seven of the nine studies reviewed herein, differences between active treatments on the primary endpoints were not dramatic. Experience in clinical practice suggests that, for many patients, oral triptans are superior to non-specific acute treatments, creating a discrepancy between clinical trials results and clinical practice experience. Four possible explanations for the disparities between clinical trials and clinical practice are likely: (i) statistically significant differences may not have emerged because the studies lack adequate statistical power; (ii) patients treated with triptans in clinical practice may be relatively more responsive to triptans and relatively less responsive to other agents than those who participate in clinical trials (patient selection); (iii) headache response at 2 h, as measured in clinical trials, may not fully capture the benefits of triptans relative to other therapies, as assessed in clinical practice; (iv) waiting until pain is moderate or severe, as required in clinical trials, may disadvantage triptans relative to comparators.

SUNCT Syndrome Responsive to Intravenous Lidocaine

Short-lasting unilateral neuralgiform headache with conjunctival injection and tearing (SUNCT) is a primary headache syndrome that has been reported to be resistant to treatment with intravenous lidocaine. We report four cases of SUNCT in whom intravenous lidocaine (1.3-3.3 mg kg−1 h−1) completely suppressed the headaches for the duration of the infusion. The headache returned after cessation of treatment. Two patients went on to have their symptoms controlled on topiramate (50-300 mg daily). One patient had typical migrainous aura in association with some of the attacks of pain but never migrainous headaches. These cases suggest that treatment with lidocaine can be considered when acute intervention is required to suppress a severe exacerbation of SUNCT, and further broaden the therapeutic and clinical background of this syndrome.

European Headache Federation consensus on technical investigation for primary headache disorders

The diagnosis of primary headache disorders is clinical and based on the diagnostic criteria of the International Headache Society (ICHD-3-beta). However several brain conditions may mimic primary headache disorders and laboratory investigation may be needed. This necessity occurs when the treating physician doubts for the primary origin of headache. Features that represent a warning for a possible underlying disorder causing the headache are new onset headache, change in previously stable headache pattern, headache that abruptly reaches the peak level, headache that changes with posture, headache awakening the patient, or precipitated by physical activity or Valsalva manoeuvre, first onset of headache ≥50 years of age, neurological symptoms or signs, trauma, fever, seizures, history of malignancy, history of HIV or active infections, and prior history of stroke or intracranial bleeding. All national headache societies and the European Headache Alliance invited to review and comment the consensus before the final draft. The consensus recommends brain MRI for the case of migraine with aura that persists on one side or in brainstem aura. Persistent aura without infarction and migrainous infarction require brain MRI, MRA and MRV. Brain MRI with detailed study of the pituitary area and cavernous sinus, is recommended for all TACs. For primary cough headache, exercise headache, headache associated with sexual activity, thunderclap headache and hypnic headache apart from brain MRI additional tests may be required. Because there is little and no good evidence the committee constructed a consensus based on the opinion of experts, and should be treated as imperfect.

INDOMETHACIN TEST USAGE AT UNITED KINGDOM TERTIARY CENTRES OVER 20 YEARS-AN AUDIT

Background

Indomethacin-responsive trigeminal autonomic cephalalagias (TACS), paroxysmal hemicrania (PH) and hemicrania continua (HC), are unique, important syndromes to understand.

Aim

Evaluation of the role of the placebo-controlled indomethacin test (P-Indotest) in the diagnosis of primary headache disorders.

Method

Patients notes, clinic letters and headache diaries of patients under our care (PJG) over a 20 year period across various UK Neurology tertiary care centres were examined to obtain data against an audit collection tool. A pre-determined set of data were extracted, and the test procedure reviewed for compliance against a standard with minimum data set requirement by an unblinded observer. The original test score was noted, and prospectively re-scored by a blinded observer.

Results

Patients (n=7; 4 female) were aged from 24 to 51 years. The majority (85%) had side locked headache. P-Indotest was positive in 78% of the cases with patients having either HC or PH. Of all patients tested, 42% had unilateral photophobia and phonophobia and all these cases had a positive response. No serious adverse events were noted. Sleepiness was often reported on the active treatment as was transient worsening of headache in unilateral chronic migraine. Further data is being compiled.

Conclusion

The P-IndoTest is a reliable and safe test and should in the diagnosis of patients with possible indomethacin sensitive TACs. While far from ideal, a positive indomethacin test does identify a particular biology and should be retained as a diagnostic marker of PH and HC until its basis is understood.

Nociception-specific blink reflex: pharmacology in healthy volunteers

BACKGROUND

The physiology and pharmacology of activation or perception of activation of pain-coding trigeminovascular afferents in humans is fundamental to understanding the biology of headache and developing new treatments.

METHODS

The blink reflex was elicited using a concentric electrode and recorded in four separate sessions, at baseline and two minutes after administration of ramped doses of diazepam (final dose 0.07 mg/kg), fentanyl (final dose 1.11 μg/kg), ketamine (final dose 0.084 mg/kg) and 0.9 % saline solution. The AUC (area under the curve, μV*ms) and the latency (ms) of the ipsi- and contralateral R2 component of the blink reflex were calculated by PC-based offline analysis. Immediately after each block of blink reflex recordings certain psychometric parameters were assessed.

RESULTS

There was an effect due to DRUG on the ipsilateral (F 3,60 = 7.3, P < 0.001) AUC as well as on the contralateral (F 3,60 = 6.02, P < 0.001) AUC across the study. A significant decrement in comparison to placebo was observed only for diazepam, affecting the ipsilateral AUC. The scores of alertness, calmness, contentedness, reaction time and precision were not affected by the DRUG across the sessions.

CONCLUSION

Previous studies suggest central, rather than peripheral changes in nociceptive trigeminal transmission in migraine. This study demonstrates a robust effect of benzodiazepine receptor modulation of the nociception specific blink reflex (nBR) without any μ-opiate or glutamate NMDA receptor component. The nociception specific blink reflex offers a reproducible, quantifiable method of assessment of trigeminal nociceptive system in humans that can be used to dissect pharmacology relevant to primary headache disorders.

Periaqueductal gray calcitonin gene-related peptide modulates trigeminovascular neurons

Background

Calcitonin gene-related peptide (CGRP) receptor antagonism is an approach to migraine therapy. The locus of action of antimigraine treatment is not resolved. The objective was to investigate CGRP receptors in the ventrolateral periaqueductal gray (vlPAG) involved in the modulation of trigeminovascular nociception by descending influences on neurotransmission.

Methods

The presence of calcitonin receptor-like receptor (CLR) and receptor activity modifying protein 1 (RAMP1), which form functional CGRP receptors, was investigated. CGRP and its receptor antagonists, olcegepant and CGRP ( 8 – 37 ), were microinjected into the vlPAG while changes of neural responses in the trigeminocervical complex (TCC) were monitored.

Results

Immunoreactivity indicated the presence of functional CGRP receptor components in the vlPAG and adjacent mesencephalic trigeminal nucleus. Inhibition of TCC responses to stimulation of dural afferents and ophthalmic cutaneous receptive fields after microinjection of bicuculline into vlPAG indicated a connection between the vlPAG and TCC neurons. CGRP facilitated these TCC responses, whereas olcegepant and CGRP ( 8 – 37 ) decreased them.

Conclusions

CGRP and its receptor antagonists act on neurons in the region of vlPAG to influence nociceptive transmission in the TCC. This suggests CGRP receptor antagonists may act at loci outside of the TCC and reinforces the concept of migraine as a disorder of the brain.

Trigeminal autonomic cephalalgias

The trigeminal autonomic cephalalgias (TACs) are a group of primary headache disorders characterised by lateralized symptoms: prominent headache and ipsilateral cranial autonomic features, such as conjunctival injection, lacrimation and rhinorrhea. The TACs are: cluster headache (CH), paroxysmal hemicrania (PH), short-lasting unilateral neuralgiform headache attacks with conjunctival injection and tearing (SUNCT)/short-lasting neuralgiform headache attacks with cranial autonomic features (SUNA) and hemicrania continua (HC). Their diagnostic criteria are outlined in the International Classification of Headache Disorders, third edition-beta (ICHD-IIIb). These conditions are distinguished by their attack duration and frequency, as well as response to treatment. HC is continuous and by definition responsive to indomethacin. The main differential when considering this headache is chronic migraine. Other TACs are remarkable for their short duration and must be distinguished from other short-lasting painful conditions, such as trigeminal neuralgia and primary stabbing headache. Cluster headache is characterised by exquisitely painful attacks that occur in discrete episodes lasting 15-180 min a few times a day. In comparison, PH occurs more frequently and is of shorter duration, and like HC is responsive to indomethacin. SUNCT/SUNA is the shortest duration and highest frequency TAC; attacks can occur over a hundred times every day.

Photic hypersensitivity in the premonitory phase of migraine--a positron emission tomography study

BACKGROUND AND PURPOSE

Sensitivity to light (photophobia) is a common ill-understood symptom of migraine, whose neurobiology is important in understanding the disorder.

METHODS

Patients reporting premonitory symptoms before migraine headache were infused with nitroglycerin (GTN) at a first visit. Patients who responded with premonitory symptoms followed by a delayed headache resembling their migraine had positron emission tomography (PET) scans at least 1 week later, during which GTN infusion was repeated. H2 (15) O PET scans were performed during baseline (pain free), premonitory phase (pain free) and migraine headache. Patients were divided into two groups, with and without photophobia in the premonitory phase. The differences between the premonitory and baseline scans were analysed within groups and between groups using statistical parametric mapping.

RESULTS

Thirteen patients participated in the PET study, 10 of whom had at least one PET scan during the premonitory phase in the absence of pain. Data from these 10 patients were included in the final analysis. Five patients had photophobia and five patients did not have photophobia in the premonitory phase. Comparing the premonitory scans to baseline scans, there was activation of extrastriate visual cortex (BA18) in patients with photophobia. This activation was significantly greater than in the patients without photophobia.

CONCLUSION

Our findings indicate that photic hypersensitivity is linked to activation of the visual cortex during the premonitory phase of migraine in the absence of headache.

Effect of noninvasive vagus nerve stimulation on acute migraine: An open-label pilot study

Background

We sought to assess a novel, noninvasive, portable vagal nerve stimulator (nVNS) for acute treatment of migraine.

Methods

Participants with migraine with or without aura were eligible for an open-label, single-arm, multiple-attack study. Up to four migraine attacks were treated with two 90-second doses, at 15-minute intervals delivered to the right cervical branch of the vagus nerve within a six-week time period. Subjects were asked to self-treat at moderate or severe pain, or after 20 minutes of mild pain.

Results

Of 30 enrolled patients (25 females, five males, median age 39), two treated no attacks, and one treated aura only, leaving a Full Analysis Set of 27 treating 80 attacks with pain. An adverse event was reported in 13 patients, notably: neck twitching ( n = 1), raspy voice ( n = 1) and redness at the device site ( n = 1). No unanticipated, serious or severe adverse events were reported. The pain-free rate at two hours was four of 19 (21%) for the first treated attack with a moderate or severe headache at baseline. For all moderate or severe attacks at baseline, the pain-free rate was 12/54 (22%).

Conclusions

nVNS may be an effective and well-tolerated acute treatment for migraine in certain patients.