Migraine is associated with altered processing of sensory stimuli

Fear, Avoidance, and Disability in Headache Disorders

PURPOSE OF REVIEW

The purpose of this review is to summarize the role of avoidance behavior in headache-related disability and overview relevant clinical implications.

RECENT FINDINGS

Avoidance occupies a central role in contemporary psychological perspectives on headache disorders and other chronic pain conditions. Several cognitive constructs of relevance to headache are influenced and maintained by avoidance behavior. A growing body of literature attests to the notion that avoidance of headache triggers, of stimuli that exacerbate headache, and of broader life domains can negatively affect headache progression, disability/quality of life, and comorbid psychiatric symptoms. Interventions targeting avoidance behavior, such as therapeutic exposure to headache triggers, mindfulness, and acceptance and commitment therapy (ACT), hold promise for headache disorders but need to be tested in larger trials. Researchers and clinicians are encouraged to attend to functional impairment as a critically important treatment outcome. Comprehensive understanding of headache disorders necessitates attention not merely to diagnostic symptoms and their reduction, but to patterns of avoidance behavior that inadvertently exacerbate headache and contribute to functional impairment.

Burden of migraine in Finland: multimorbidity and phenotypic disease networks in occupational healthcare

BACKGROUND

Migraine is a complex neurological disorder with high co-existing morbidity burden. The aim of our study was to examine the overall morbidity and phenotypic diseasome for migraine among people of working age using real world data collected as a part of routine clinical practice.

METHODS

Electronic medical records (EMR) of patients with migraine (n = 17,623) and age- and gender matched controls (n = 17,623) were included in this retrospective analysis. EMRs were assessed for the prevalence of ICD-10 codes, those with at least two significant phi correlations, and a prevalence >2.5% in migraine patients were included to phenotypic disease networks (PDN) for further analysis. An automatic subnetwork detection algorithm was applied in order to cluster the diagnoses within the PDNs. The diagnosis-wise connectivity based on the PDNs was compared between migraine patients and controls to assess differences in morbidity patterns.

RESULTS

The mean number of diagnoses per patient was increased 1.7-fold in migraine compared to controls. Altogether 1337 different ICD-10 codes were detected in EMRs of migraine patients. Monodiagnosis was present in 1% and 13%, and the median number of diagnoses was 12 and 6 in migraine patients and controls. The number of significant phi-correlations was 2.3-fold increased, and cluster analysis showed more clusters in those with migraine vs. controls (9 vs. 6). For migraine, the PDN was larger and denser and exhibited one large cluster containing fatigue, respiratory, sympathetic nervous system, gastrointestinal, infection, mental and mood disorder diagnoses. Migraine patients were more likely affected by multiple conditions compared to controls, even if no notable differences in morbidity patterns were identified through connectivity measures. Frequencies of ICD-10 codes on a three character and block level were increased across the whole diagnostic spectrum in migraine.

CONCLUSIONS

Migraine was associated with an increased multimorbidity, evidenced by multiple different approaches in the study. A systematic increase in the morbidity across the whole spectrum of ICD-10 coded diagnoses, and when interpreting PDNs, were detected in migraine patients. However, no specific diagnoses explained the morbidity. The results reflect clinical praxis, but also undoubtedly, the pathophysiological phenotypes related to migraine, and emphasize the importance of better understanding migraine-related morbidity.

Genetic Screening of Plasticity Regulating Nogo-Type Signaling Genes in Migraine

Migraine is the sixth most prevalent disease in the world and a substantial number of experiments have been conducted to analyze potential differences between the migraine brain and the healthy brain. Results from these investigations point to the possibility that development and aggravation of migraine may include grey matter plasticity. Nogo-type signaling is a potent plasticity regulating system in the CNS and consists of ligands, receptors, co-receptors and modulators with a dynamic age- and activity-related expression in cortical and subcortical regions. Here we investigated a potential link between migraine and five key Nogo-type signaling genes: RTN4, OMGP, MAG, RTN4R and LINGO1, by screening 15 single nucleotide polymorphisms (SNPs) within these genes. In a large Swedish migraine cohort (749 migraine patients and 4032 controls), using a logistic regression with sex as covariate, we found that there was no such association. In addition, a haplotype analysis was performed which revealed three haplotype blocks. These blocks had no significant association with migraine. However, to robustly conclude that Nogo-type genotypes signaling do not influence the prevalence of migraine, further studies are encouraged.

The involvement of altered sensory modulation in neurological conditions and its relevance to neuro-rehabilitation: a narrative literature review

PURPOSE

Neurological conditions are frequently described and treated with emphasis on primarily body dysfunctions that appear in the diagnostic criteria. This perspective paper aims to provide knowledge about the involvement of secondary body dysfunctions - altered sensory modulation - in neurological conditions and their relevance to neuro-rehabilitation. This paper refers to children and adults, to provide a life span view. Health models and approaches are discussed to bring ideas for optimizing rehabilitation.

METHODS

Perspective based on narrative literature review.

RESULTS

Altered sensory modulation is prevalent in neurological conditions. It is related to clinical symptoms, comorbidities and severity level. Many studies focus on specific modalities and on laboratory/clinical measurements. However, information gathered from subjective measures reflects the alterations in various sensory modalities and their negative impacts on the individuals' daily activity performance, participation and quality of life (QOL).

CONCLUSIONS

Neuro-rehabilitation should consider altered sensory modulation in neurological conditions, apply health models with broad perspective, as the ICF, with multi-disciplinary team, objective and subjective measures to understand how pathogenic mechanisms in primary and secondary body dysfunctions impact the performance and participation in daily life. This approach may optimize the individuals' involvement in therapy, enhance daily function and QOL and elevate intervention success.Implications for rehabilitationSensory modulation should be evaluated in children and adults with neurologic conditions.The evaluation and intervention should refer to the involvement of altered sensory modulation in the conditions' clinical characteristics, severity and comorbidities.In case altered sensory modulation is found, the evaluation and intervention should incorporate a multi-disciplinary collaboration and health models such as the ICF model, to optimize neuro-rehabilitation efficiency.Objective measures should be applied to profile altered sensory modulation and its role in pathogenic mechanisms.Subjective measures should also be used to reflect the expressions of altered sensory modulation as experienced by the individual (and family members), in daily life scenarios.By bridging between the clinic and the individuals' real-life context, rehabilitation process and outcomes may be optimized, in terms of the individual's greater involvement in therapy, better function and quality of life.

Efficacy of Multi-Modal Migraine Prophylaxis Therapy on Hyperacusis Patients

OBJECTIVES

To evaluate the efficacy of a multi-modal migraine prophylaxis therapy for patients with hyperacusis.

METHODS

In a prospective cohort, patients with hyperacusis were treated with a multi-modal step-wise migraine prophylactic regimen (nortriptyline, verapamil, topiramate, or a combination thereof) as well as lifestyle and dietary modifications. Pre- and post-treatment average loudness discomfort level (LDL), hyperacusis discomfort level measured by a visual analogue scale (VAS), and scores on the modified Khalfa questionnaire for severity of hyperacusis were compared.

RESULTS

Twenty-two of the 25 patients (88%) reported subjective resolution of their symptoms following treatment. Post-treatment audiograms showed significant improvement in average LDL from 81.3 ± 3.2 dB to 86.4 ± 2.6 dB (P < .001), indicating increased sound tolerability. The VAS discomfort level also showed significant improvement from a pre-treatment average of 7.7 ± 1.1 to 3.7 ± 1.6 post-treatment (P < .001). There was also significant improvement in the average total score on modified Khalfa questionnaire (32.2 ± 3.6 vs 22.0 ± 5.7, P < .001).

CONCLUSIONS

The majority of patients with hyperacusis demonstrated symptomatic improvement from migraine prophylaxis therapy, as indicated by self-reported and audiometric measures. Our findings indicate that, for some patients, hyperacusis may share a pathophysiologic basis with migraine disorder and may be successfully managed with multimodal migraine prophylaxis therapy.

C-tactile touch perception in migraineurs – a case-control study

Background

Migraine is characterized by sensory hypersensitivity and habituation deficits. Slow brushing over the skin activates C-tactile nerve fibers, which mediate pleasant touch and analgesic effects in healthy subjects. As this function is altered in painful conditions, we aimed to examine whether the C-tactile processing is disrupted in migraines.

Methods

To psychophysically assess C-tactile function, we applied optimal and suboptimal C-tactile stroking stimuli on the dorsal forearm (body reference area) and the trigeminally innervated skin of 52 interictal migraineurs and 52 matched healthy controls. For habituation testing, 60 repeated C-tactile optimal stimuli were presented in both test areas. The participants rated each stimulus on a visual analogue scale by intensity, pleasantness, and painfulness.

Results

Regarding C-tactile function, migraineurs showed unphysiological rating patterns but no significantly different pleasantness ratings than controls. During repeated stimulation, controls showed stable pleasantness ratings while migraineurs’ ratings decreased, especially in those experiencing tactile allodynia during headaches. Migraineurs taking triptans responded like controls.

Conclusion

The C-tactile function of migraineurs is subclinically altered. Repeated C-tactile stimulation leads to altered habituation but differs from previous work by the direction of the changes. Although the pathophysiology remains unknown, causative mechanisms could include central and peripheral neuronal sensitization, tactile allodynia and hedonic stimulus attributions.

Functional connectivity of music-induced analgesia in fibromyalgia

Listening to self-chosen, pleasant and relaxing music reduces pain in fibromyalgia (FM), a chronic centralized pain condition. However, the neural correlates of this effect are fairly unknown. In our study, we wished to investigate the neural correlates of music-induced analgesia (MIA) in FM patients. To do this, we studied 20 FM patients and 20 matched healthy controls (HC) acquiring rs-fMRI with a 3T MRI scanner, and pain data before and after two 5-min auditory conditions: music and noise. We performed resting state functional connectivity (rs-FC) seed-based correlation analyses (SCA) using pain and analgesia-related ROIs to determine the effects before and after the music intervention in FM and HC, and its correlation with pain reports. We found significant differences in baseline rs-FC between FM and HC. Both groups showed changes in rs-FC after the music condition. FM patients reported MIA that was significantly correlated with rs-FC decrease between the angular gyrus, posterior cingulate cortex and precuneus, and rs-FC increase between amygdala and middle frontal gyrus. These areas are related to autobiographical and limbic processes, and auditory attention, suggesting MIA may arise as a consequence of top-down modulation, probably originated by distraction, relaxation, positive emotion, or a combination of these mechanisms.

Association of Tinnitus and Other Cochlear Disorders With a History of Migraines

Importance

A headache is a symptom of a migraine, but not all patients with migraine have headaches. It is still unclear whether a migraine might increase the risk of cochlear disorders, even though a migraine does not occur concurrently with cochlear disorders.

Objective

To investigate the risk of cochlear disorders for patients with a history of migraines.

Design, Setting, and Participants

This study used claims data from the Taiwan Longitudinal Health Insurance Database 2005 to identify 1056 patients with migraines diagnosed between January 1, 1996, and December 31, 2012. A total of 4224 controls were also identified from the same database based on propensity score matching. Statistical analysis was performed from January 23, 1996, to December 28, 2012.

Main Outcomes and Measures

The incidence rate of cochlear disorders (tinnitus, sensorineural hearing impairment, and/or sudden deafness) was compared between the cohorts by use of the Kaplan-Meier method. The Cox proportional hazards regression model was also used to examine the association of cochlear disorders with migraines.

Results

Of the 1056 patients with migraines, 672 were women and 384 were men, and the mean (SD) age was 36.7 (15.3) years. Compared with the nonmigraine cohort, the crude hazard ratio for cochlear disorders in the migraine cohort was 2.83 (95% CI, 2.01-3.99), and the adjusted hazard ratio was 2.71 (95% CI, 1.86-3.93). The incidence rates of cochlear disorders were 81.4 (95% CI, 81.1-81.8) per 1 million person-years for the migraine cohort and 29.4 (95% CI, 29.2-29.7) per 1 million person-years for the nonmigraine cohort. The cumulative incidence of cochlear disorders in the migraine cohort (12.2%) was significantly higher than that in the matched nonmigraine cohort (5.5%). Subgroup analysis showed that, compared with the nonmigraine cohort, the adjusted hazard ratios in the migraine cohort were 3.30 (95% CI, 2.17-5.00) for tinnitus, 1.03 (95% CI, 0.17-6.41) for sensorineural hearing impairment, and 1.22 (95% CI, 0.53-2.83) for sudden deafness.

Conclusions and Relevance

In this population-based study, the risk of cochlear disorders, especially for tinnitus, was found to be significantly higher among patients with a history of migraines. This finding may support the presence and/or concept of "cochlear migraine."

Primary headache and migraine in headache specialists – does personal history of doctors matter?

Objective

Migraine is a common disorder affecting more than 10% of the population. The prevalence of migraine among physicians and, in particular, among headache specialists is widely unknown as is the impact of suffering from migraine on the attitudes towards migraine and on treatment recommendations of physicians. We designed a survey among headache specialists and neurologists and compared the results to general pain specialists and general practitioners.

Methods

A standardized interview in randomly selected samples of these four groups of physicians was performed. The interview included data on the prevalence of migraine and other primary headache disorders in the physician groups, self-report on their own treatment, attitudes towards migraine, and treatment recommendations for migraine. The prevalence rates were also compared to an age- and sex-matched German general population sample.

Results

The lifetime prevalence of migraine was higher in headache specialists (53.0%) than in general neurologists (43.0%), pain specialists (21.7%), general practitioners (19.3%), and in the general age- and sex-matched population (16.8%). Cluster headache prevalence was high in neurologists (1.9%) and in headache specialists (1.3%); episodic tension-type headache prevalence was significantly lower in general practitioners (19.5%). One reason, among others, was that being a migraine (or cluster headache) patient more often prompted the sufferers to become a specialist in neurology. Physicians with migraine rated the biopsychosocial concept of lower importance for migraine than did physicians without migraine. The self-treatment of migraine in physicians differs from the treatment recommendations to the patients. For example, only 36.4% of the headache specialists with migraine take triptans whereas 94.4% recommend triptans to their patients.

Conclusions

We conclude that being a headache specialist or a neurologist is associated with an increased migraine or cluster headache prevalence. This personal history of migraine leads to a more somatic view of migraine as a disorder and to different treatment recommendations as compared to self-treatment.

Photoactivation of olfactory sensory neurons does not affect action potential conduction in individual trigeminal sensory axons innervating the rodent nasal cavity

Olfactory and trigeminal chemosensory systems reside in parallel within the mammalian nose. Psychophysical studies in people indicate that these two systems interact at a perceptual level. Trigeminal sensations of pungency mask odour perception, while olfactory stimuli can influence trigeminal signal processing tasks such as odour localization. While imaging studies indicate overlap in limbic and cortical somatosensory areas activated by nasal trigeminal and olfactory stimuli, there is also potential cross-talk at the level of the olfactory epithelium, the olfactory bulb and trigeminal brainstem. Here we explored the influence of olfactory and trigeminal signaling in the nasal cavity. A forced choice water consumption paradigm was used to ascertain whether trigeminal and olfactory stimuli could influence behaviour in mice. Mice avoided water sources surrounded by both volatile TRPV1 (cyclohexanone) and TRPA1 (allyl isothiocyanate) irritants and the aversion to cyclohexanone was mitigated when combined with a pure odorant (rose fragrance, phenylethyl alcohol, PEA). To determine whether olfactory-trigeminal interactions within the nose could potentially account for this behavioural effect we recorded from single trigeminal sensory axons innervating the nasal respiratory and olfactory epithelium using an isolated in vitro preparation. To circumvent non-specific effects of chemical stimuli, optical stimulation was used to excite olfactory sensory neurons in mice expressing channel-rhodopsin (ChR2) under the olfactory marker protein (OMP) promoter. Photoactivation of olfactory sensory neurons produced no modulation of axonal action potential conduction in individual trigeminal axons. Similarly, no evidence was found for collateral branching of trigeminal axon that might serve as a conduit for cross-talk between the olfactory and respiratory epithelium and olfactory dura mater. Using direct assessment of action potential activity in trigeminal axons we observed neither paracrine nor axon reflex mediated cross-talk between olfactory and trigeminal sensory systems in the rodent nasal cavity. Our current results suggest that olfactory sensory neurons exert minimal influence on trigeminal signals within the nasal cavity.

Brainstem neuroimaging of nociception and pain circuitries

The brainstem is known to be an important brain area for nociception and pain processing, and both relaying and coordinating signaling between the cerebrum, cerebellum, and spinal cord. Although preclinical models of pain have characterized the many roles that brainstem nuclei play in nociceptive processing, the degree to which these circuitries extend to humans is not as well known. Unfortunately, the brainstem is also a very challenging region to evaluate in humans with neuroimaging. The challenges for human brainstem imaging arise from the location of this elongated brain structure, proximity to cardiorespiratory noise sources, and the size of its constituent nuclei. These challenges can require dedicated approaches to brainstem imaging, which should be adopted when study hypotheses are focused on brainstem processing of nociception or modulation of pain perception. In fact, our review will highlight many pain neuroimaging studies that have reported some brainstem involvement in nociceptive processing and chronic pain pathology. However, we note that with recent advances in neuroimaging leading to improved spatial and temporal resolution, more studies are needed that take advantage of data collection and analysis methods focused on the challenges of brainstem neuroimaging.

Sensory Modulation Disorder (SMD) and Pain: A New Perspective

Sensory modulation disorder (SMD) affects sensory processing across single or multiple sensory systems. The sensory over-responsivity (SOR) subtype of SMD is manifested clinically as a condition in which non-painful stimuli are perceived as abnormally irritating, unpleasant, or even painful. Moreover, SOR interferes with participation in daily routines and activities (Dunn, 2007; Bar-Shalita et al., 2008; Chien et al., 2016), co-occurs with daily pain hyper-sensitivity, and reduces quality of life due to bodily pain. Laboratory behavioral studies have confirmed abnormal pain perception, as demonstrated by hyperalgesia and an enhanced lingering painful sensation, in children and adults with SMD. Advanced quantitative sensory testing (QST) has revealed the mechanisms of altered pain processing in SOR whereby despite the existence of normal peripheral sensory processing, there is enhanced facilitation of pain-transmitting pathways along with preserved but delayed inhibitory pain modulation. These findings point to central nervous system (CNS) involvement as the underlying mechanism of pain hypersensitivity in SOR. Based on the mutual central processing of both non-painful and painful sensory stimuli, we suggest shared mechanisms such as cortical hyper-excitation, an excitatory-inhibitory neuronal imbalance, and sensory modulation alterations. This is supported by novel findings indicating that SOR is a risk factor and comorbidity of chronic non-neuropathic pain disorders. This is the first review to summarize current empirical knowledge investigating SMD and pain, a sensory modality not yet part of the official SMD realm. We propose a neurophysiological mechanism-based model for the interrelation between pain and SMD. Embracing the pain domain could significantly contribute to the understanding of this condition’s pathogenesis and how it manifests in daily life, as well as suggesting the basis for future potential mechanism-based therapies.

Sensory Processing Difficulties Correlate With Disease Severity and Quality of Life Among Children With Migraine

Introduction: Headaches are common among children and about 80% of children reporting them. Migraine and tension type headaches are the most common primary headaches in children and the prevalence of migraine is about 8%. Accompanying sensory symptoms are common before, during and after migraine attacks. They may be a part of a wider symptom constellation called sensory processing disorder or difficulties (SPD). This includes both hyper or hypo sensitivity to sensations. However, the literature regarding sensory processing symptoms of children and youth with headaches as well as its interaction with child's emotional aspects and quality of life is scarce. Materials and Methods: One hundred and thirty-four children between the ages of 8 and 12 participated in this study. Fifty-four children (22 boys and 32 girls) with episodic migraine were prospectively recruited from pediatric neurological clinics during the years 2014-2017. The control group included 80 healthy children. Both groups completed a health and demographic questionnaire, headache assessment including Ped-MIDAS, Short Sensory Profile, State-Trait Anxiety Inventory (STAI) for children, and the Pediatric Quality of Life Inventory. Results: Children with migraine showed significantly higher prevalence of sensory processing difficulties and lower quality of life compared to healthy controls. Among children with migraine, sensory processing difficulties significantly correlated with lower quality of life. Headache-related disability and sensory processing difficulties predicted quality of life. Conclusion: The possible relationship between migraine and sensory processing disorder or difficulties stresses the need to screen for sensory processing difficulties among children with migraine and when found-refer to their impacts on children's daily function and quality of life.

Perivascular neurotransmitters: Regulation of cerebral blood flow and role in primary headaches

In order to understand the nature of the relationship between cerebral blood flow (CBF) and primary headaches, we have conducted a literature review with particular emphasis on the role of perivascular neurotransmitters. Primary headaches are in general considered complex polygenic disorders (genetic and environmental influence) with pathophysiological neurovascular alterations. Identified candidate headache genes are associated with neuro- and gliogenesis, vascular development and diseases, and regulation of vascular tone. These findings support a role for the vasculature in primary headache disorders. Moreover, neuronal hyperexcitability and other abnormalities have been observed in primary headaches and related to changes in hemodynamic factors. In particular, this relates to migraine aura and spreading depression. During headache attacks, ganglia such as trigeminal and sphenopalatine (located outside the blood-brain barrier) are variably activated and sensitized which gives rise to vasoactive neurotransmitter release. Sympathetic, parasympathetic and sensory nerves to the cerebral vasculature are activated. During migraine attacks, altered CBF has been observed in brain regions such as the somatosensory cortex, brainstem and thalamus. In regulation of CBF, the individual roles of neurotransmitters are partly known, but much needs to be unraveled with respect to headache disorders.

Association between migraine frequency and neural response to emotional faces: An fMRI study

Previous studies have demonstrated that migraine is associated with enhanced perception and altered cerebral processing of sensory stimuli. More recently, it has been suggested that this sensory hypersensitivity might reflect a more general enhanced response to aversive emotional stimuli. Using functional magnetic resonance imaging and emotional face stimuli (fearful, happy and sad faces), we compared whole-brain activation between 41 migraine patients without aura in interictal period and 49 healthy controls. Migraine patients showed increased neural activation to fearful faces compared to neutral faces in the right middle frontal gyrus and frontal pole relative to healthy controls. We also found that higher attack frequency in migraine patients was related to increased activation mainly in the right primary somatosensory cortex (corresponding to the face area) to fearful expressions and in the right dorsal striatal regions to happy faces. In both analyses, activation differences remained significant after controlling for anxiety and depressive symptoms. These findings indicate that enhanced response to emotional stimuli might explain the migraine trigger effect of psychosocial stressors that gradually leads to increased somatosensory response to emotional clues and thus contributes to the progression or chronification of migraine.

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First fMRI study to explore neural response to emotional faces in migraine patients

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Migraine patients showed increased activation to fear in the right frontal regions

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Migraine frequency was related to enhanced activation to fearful and happy faces

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Activation in the right S1 and dorsal striatum was linked to migraine frequency

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Sensitivity to emotional stimuli might have a role in triggering migraine

Treating Chronic Migraine With Neuromodulation: The Role of Neurophysiological Abnormalities and Maladaptive Plasticity

Chronic migraine (CM) is the most disabling form of migraine, because pharmacological treatments have low efficacy and cumbersome side effects. New evidence has shown that migraine is primarily a disorder of brain plasticity and migraine chronification depends on a maladaptive process favoring the development of a brain state of hyperexcitability. Due to the ability to induce plastic changes in the brain, researchers started to look at Non-Invasive Brain Stimulation (NIBS) as a possible therapeutic option in migraine field. On one side, NIBS techniques induce changes of neural plasticity that outlast the period of the stimulation (a fundamental prerequisite of a prophylactic migraine treatment, concurrently they allow targeting neurophysiological abnormalities that contribute to the transition from episodic to CM. The action may thus influence not only the cortex but also brainstem and diencephalic structures. Plus, NIBS is not burdened by serious medication side effects and drug–drug interactions. Although the majority of the studies reported somewhat beneficial effects in migraine patients, no standard intervention has been defined. This may be due to methodological differences regarding the used techniques (e.g., transcranial magnetic stimulation, transcranial direct current stimulation), the brain regions chosen as targets, and the stimulation types (e.g., the use of inhibitory and excitatory stimulations on the basis of opposite rationales), and an intrinsic variability of stimulation effect. Hence, it is difficult to draw a conclusion on the real effect of neuromodulation in migraine. In this article, we first will review the definition and mechanisms of brain plasticity, some neurophysiological hallmarks of migraine, and migraine chronification-related (dys)plasticity. Secondly, we will review available results from therapeutic and physiological studies using neuromodulation in CM. Lastly we will discuss the results obtained in these preventive trials in the light of a possible effect on brain plasticity.

Abnormal functional connectivity under somatosensory stimulation in migraine: a multi-frequency magnetoencephalography study

BACKGROUND

Although altered neural networks have been demonstrated in recent MEG (magnetoencephalography) research in migraine patients during resting state, it is unknown whether this alteration can be detected in task-related networks. The present study aimed to investigate the abnormalities of the frequency-specific somatosensory-related network in migraine patients by using MEG.

METHODS

Twenty-two migraineurs in the interictal phase and twenty-two sex- and age-matched healthy volunteers were studied using a whole-head magnetoencephalography (MEG) system. Electrical stimuli were delivered alternately to the median nerve on the right wrists of all subjects. MEG data were analyzed in a frequency range of 1-1000 Hz in multiple bands.

RESULTS

The brain network patterns revealed that the patients with migraine exhibited remarkably increased functional connectivity in the high-frequency (250-1000 Hz) band between the sensory cortex and the frontal lobe. The results of quantitative analysis of graph theory showed that the patients had (1) an increased degree of connectivity in the theta (4-8 Hz), beta (13-30 Hz) and gamma (30-80 Hz) bands; (2) an increased connectivity strength in the beta (13-30 Hz) and gamma (30-80 Hz) bands; (3) an increased path length in the beta (13-30 Hz), gamma (30-80 Hz) and ripple (80-250 Hz) bands; and (4) an increased clustering coefficient in the theta (4-8 Hz), beta (13-30 Hz) and gamma (30-80 Hz) bands.

CONCLUSIONS

The results indicate that migraine is associated with aberrant connections from the somatosensory cortex to the frontal lobe. The frequency-specific increases in connectivity in terms of strength, path length and clustering coefficients support the notion that migraineurs have elevated cortical networks. This alteration in functional connectivity may be involved in somatosensory processing in migraine patients and may contribute to understanding migraine pathophysiology and to providing convincing evidence for a spatially targeted migraine therapy.

Modulation of brainstem activity and connectivity by respiratory-gated auricular vagal afferent nerve stimulation in migraine patients

Migraine pathophysiology includes altered brainstem excitability, and recent neuromodulatory approaches aimed at controlling migraine episodes have targeted key brainstem relay and modulatory nuclei. In this study, we evaluated the impact of respiratory-gated auricular vagal afferent nerve stimulation (RAVANS), a novel neuromodulatory intervention based on an existing transcutaneous vagus nerve stimulation approach, in the modulation of brainstem activity and connectivity in migraine patients. We applied 3T-functional magnetic resonance imaging with improved in-plane spatial resolution (2.62 × 2.62 mm) in episodic migraine (interictal) and age- and sex-matched healthy controls to evaluate brain response to RAVANS (gated to either inhalation or exhalation) and sham stimulation. We further investigated RAVANS modulation of tactile trigeminal sensory afference response in the brainstem using air-puff stimulation directed to the forehead during functional magnetic resonance imaging. Compared with sham and inhalatory-gated RAVANS (iRAVANS), exhalatory-gated RAVANS (eRAVANS) activated an ipsilateral pontomedullary region consistent with nucleus tractus solitarii (NTS). During eRAVANS, NTS connectivity was increased to anterior insula and anterior midcingulate cortex, compared with both sham and iRAVANS, in migraine patients. Increased connectivity was inversely correlated with relative time to the next migraine attack, suggesting clinical relevance to this change in connectivity. Poststimulation effects were also noted immediately after eRAVANS, as we found increased activation in putative pontine serotonergic (ie, nucleus raphe centralis) and noradrenergic (ie, locus coeruleus) nuclei in response to trigeminal sensory afference. Regulation of activity and connectivity of brainstem and cortical regions involved in serotonergic and noradrenergic regulation and pain modulation may constitute an underlying mechanism supporting beneficial clinical outcomes for eRAVANS applied for episodic migraine.

Visual stimulation leads to activation of the nociceptive trigeminal nucleus in chronic migraine

Objective

The visual system has often been described to be sensitized in migraineurs, with light being perceived as aversive or even painful. One possible explanation for this altered perception is crosslinks between the visual and the trigeminonociceptive system. Visual stimulation in chronic migraineurs on the level of the brainstem might lead to enhanced activity within the spinal trigeminal nucleus (sTN) as the main site of trigeminal pain processing within this area.

Methods

Eighteen episodic migraineurs (EM), 17 chronic migraineurs (CM), and 19 healthy controls (HC) underwent one session of high-resolution brainstem imaging during which a rotating checkerboard was presented repeatedly as a visual stimulus. Data were analyzed using SPM12 and MATLAB with the classic first-level–second-level approach of SPM. Analyses of variance were used for group comparisons.

Results

CM showed enhanced activation within the sTN as compared to HC. In addition, we observed enhanced activity within the right superior colliculus in CM as compared to HC. When comparing all migraineurs with headaches during scanning with all migraineurs without headaches during scanning and HC, we also found the sTN to be more strongly activated during headaches.

Conclusion

Our data provide evidence for the existence of visual–nociceptive integration on brainstem level in chronic migraineurs.

Has aerobic exercise effect on pain perception in persons with migraine and coexisting tension-type headache and neck pain? A randomized, controlled, clinical trial

BACKGROUND

A large subset of persons with migraine suffers from coexisting tension-type headache and neck pain which may adversely affect the prognosis of migraine. Aerobic exercise has been shown to decrease migraine burden in these persons. Therefore, the aim of this study was to investigate whether the effect of aerobic exercise in persons with migraine and coexisting tension-type headache and neck pain can be explained by changes in pain perception.

METHOD

Seventy consecutively recruited persons with migraine and coexisting tension-type headache and neck pain were randomized into exercise group or control group. Aerobic exercise consisted of bike/cross-trainer/brisk walking for 45 min, three times/week for 3 months. Controls continued their usual daily activities. Pericranial tenderness, pain thresholds, supra-thresholds and temporal summation were assessed at baseline, after treatment and at follow-up (6 months from baseline).

RESULTS

Fifty-two persons with migraine and coexisting tension-type headache and neck pain completed the study. Aerobic exercise did not induce consistent changes in nociceptive pathways measured by pericranial tenderness, pressure pain thresholds and sensitivity to electrical stimulation.

CONCLUSION

The effect of aerobic exercise cannot be explained by measurable effects on the pain modulation system. Thus, the positive effect on migraine burden may rather be explained by positive alteration of avoidance behaviour. Aerobic exercise can be recommended as a safe and inexpensive migraine treatment strategy.

SIGNIFICANCE

This study adds further knowledge about the positive effect of aerobic exercise for persons with migraine and coexisting tension-type headache and neck pain. This effect cannot be measured by changes in pain modulation, but may rather be explained by positive alteration of avoidance behaviour.

Assessment of Responsiveness to Everyday Non-Noxious Stimuli in Pain-Free Migraineurs With Versus Without Aura

Migraineurs with aura (MWA) express higher interictal response to non-noxious and noxious experimental sensory stimuli compared with migraineurs without aura (MWoA), but whether these differences also prevail in response to everyday non-noxious stimuli is not yet explored. This is a cross-sectional study testing 53 female migraineurs (30 MWA; 23 MWoA) who underwent a wide battery of noxious psychophysical testing at a pain-free phase, and completed a Sensory Responsiveness Questionnaire and pain-related psychological questionnaires. The MWA group showed higher questionnaire-based sensory over-responsiveness (P = .030), higher magnitude of pain temporal summation (P = .031) as well as higher monthly attack frequency (P = .027) compared with the MWoA group. Overall, 45% of migraineurs described abnormal sensory (hyper- or hypo-) responsiveness; its incidence was higher among MWA (19 of 30, 63%) versus MWoA (6 of 23, 27%, P = .012), with an odds ratio of 3.58 for MWA. Sensory responsiveness scores were positively correlated with attack frequency (r = .361, P = .008) and temporal summation magnitude (r = .390, P = .004), both regardless of migraine type. MWA express higher everyday sensory responsiveness than MWoA, in line with higher response to experimental noxious stimuli. Abnormal scores of sensory responsiveness characterize people with sensory modulation dysfunction, suggesting possible underlying mechanisms overlap, and possibly high incidence of both clinical entities.

PERSPECTIVE

This article presents findings distinguishing MWA, showing enhanced pain amplification, monthly attack frequency, and over-responsiveness to everyday sensations, compared with MWoA. Further, migraine is characterized by a high incidence of abnormal responsiveness to everyday sensation, specifically sensory over-responsiveness, that was also found related to pain.

Differential Development of Facial and Hind Paw Allodynia in a Nitroglycerin-Induced Mouse Model of Chronic Migraine: Role of Capsaicin Sensitive Primary Afferents

Despite the relatively high prevalence of migraine or headache, the pathophysiological mechanisms triggering headache-associated peripheral hypersensitivities, are unknown. Since nitric oxide (NO) is well known as a causative factor in the pathogenesis of migraine or migraine-associated hypersensitivities, a mouse model has been established using systemic administration of the NO donor, nitroglycerin (NTG). Here we tried to investigate the time course development of facial or hindpaw hypersensitivity after repetitive NTG injection. NTG (10 mg/kg) was administrated to mice every other day for nine days. Two hours post-injection, NTG produced acute mechanical and heat hypersensitivity in the hind paws. By contrast, cold allodynia, but not mechanical hypersensitivity, occurred in the facial region. Moreover, this hindpaws mechanical hypersensitivity and the facial cold allodynia was progressive and long-lasting. We subsequently examined whether the depletion of capsaicin-sensitive primary afferents (CSPAs) with resiniferatoxin (RTX, 0.02 mg/kg) altered these peripheral hypersensitivities in NTG-treated mice. RTX pretreatment did not affect the NTG-induced mechanical allodynia in the hind paws nor the cold allodynia in the facial region, but it did inhibit the development of hind paw heat hyperalgesia. Similarly, NTG injection produced significant hindpaw mechanical allodynia or facial cold allodynia, but not heat hyperalgesia in transient receptor potential type V1 (TRPV1) knockout mice. These findings demonstrate that different peripheral hypersensitivities develop in the face versus hindpaw regions in a mouse model of repetitive NTG-induced migraine, and that these hindpaw mechanical hypersensitivity and facial cold allodynia are not mediated by the activation of CSPAs.

Sensory Over-Responsiveness among Healthy Subjects is Associated with a Pronociceptive State

OBJECTIVE

Chronic pain patients show hypersensitivity to sensory nonpainful stimuli. Sensory over-responsiveness (SOR) to innocuous daily stimuli, experienced as painful, is prevalent in 10% of the healthy population. This altered sensory processing may be an expression of overfacilitation, or a less efficient pain-inhibitory process in the pain pathways. We therefore aimed to investigate specifically the pain-inhibitory system of subjects with SOR who are otherwise healthy, not studied as of yet.

METHODS

Thirty healthy subjects, divided into an SOR group (n = 14) and a non-SOR group (n = 16) based on responses to the Sensory Responsiveness Questionnaire, were psychophysically tested in order to evaluate (1) hyperalgesic responses; (2) adaptation/sensitization to 14 phasic heat stimuli; (3) habituation; (4) 6-minute after-sensations; and (5) conditioned pain modulation (CPM) (ie, phasic heat stimuli applied with and without hand immersion in a hot water bath).

RESULTS

The SOR group differed from the non-SOR group in (1) a steeper escalation in NPS ratings to temperature increase (P = 0.003), indicating hyperalgesia; (2) increased sensitization (P < 0.001); (3) habituation responses (P < 0.001); (4) enhanced pain ratings during the after-sensation (P = 0.006); and (5) no group difference was found in CPM.

CONCLUSIONS

SOR is associated with a pronociceptive state, expressed by amplification of experimental pain, yet with sufficient inhibitory processes. Our results support previous findings of enhanced facilitation of pain-transmitting pathways but also reveal preserved inhibitory mechanisms, although they were slower to react.

Habituation of laser-evoked potentials by migraine phase: a blinded longitudinal study

Background

Migraineurs seem to have cyclic variations in cortical excitability in several neurophysiological modalities. Laser-evoked potentials (LEP) are of particular interest in migraine because LEP specifically targets pain pathways, and studies have reported different LEP-changes both between and during headaches. Our primary aim was to explore potential cyclic variations in LEP amplitude and habituation in more detail with a blinded longitudinal study design.

Methods

We compared N1 and N2P2 amplitudes and habituation between two blocks of laser stimulations to the dorsal hand, obtained from 49 migraineurs with four sessions each. We used migraine diaries to categorize sessions as interictal (> one day from previous and to next attack), preictal (< one day before the attack), ictal or postictal (< one day after the attack). Also, we compared 29 interictal recordings from the first session to 30 controls.

Results

N1 and N2P2 amplitudes and habituation did not differ between preictal, interictal and postictal phase sessions, except for a post hoc contrast that showed deficient ictal habituation of N1. Habituation is present and similar in migraineurs in the interictal phase and controls.

Conclusions

Hand-evoked LEP amplitudes and habituation were mainly invariable between migraine phases, but this matter needs further study. Because hand-evoked LEP-habituation was similar in migraineurs and controls, the present findings contradict several previous LEP studies. Pain-evoked cerebral responses are normal and show normal habituation in migraine.

Electronic supplementary material

The online version of this article (10.1186/s10194-017-0810-6) contains supplementary material, which is available to authorized users.

Altered thalamic connectivity during spontaneous attacks of migraine without aura: A resting-state fMRI study

Background

Functional connectivity of brain networks may be altered in migraine without aura patients. Functional magnetic resonance imaging (fMRI) studies have demonstrated changed activity in the thalamus, pons and cerebellum in migraineurs. Here, we investigated the thalamic, pontine and cerebellar network connectivity during spontaneous migraine attacks.

Methods

Seventeen patients with episodic migraine without aura underwent resting-state fMRI scan during and outside of a spontaneous migraine attack. Primary endpoint was a difference in functional connectivity between the attack and the headache-free days. Functional connectivity was assessed in four different networks using seed-based analysis. The chosen seeds were in the thalamus (MNI coordinates x,y,z: right, 22,–24,0 and left, –22,–28,6), pons (right, 8,–24,–32 and left, –8,–24,–32), cerebellum crus I (right, 46,–58,–30 and left, –46,–58,–30) and cerebellum lobule VI (right, 34,–42,–36 and left, –32,–42,–36).

Results

We found increased functional connectivity between the right thalamus and several contralateral brain regions (superior parietal lobule, insular cortex, primary motor cortex, supplementary motor area and orbitofrontal cortex). There was decreased functional connectivity between the right thalamus and three ipsilateral brain areas (primary somatosensory cortex and premotor cortex). We found no change in functional connectivity in the pontine or the cerebellar networks.

Conclusions

The study indicates that network connectivity between thalamus and pain modulating as well as pain encoding cortical areas are affected during spontaneous migraine attacks.

Challenges and opportunities for brainstem neuroimaging with ultrahigh field MRI

The human brainstem plays a central role in connecting the cerebrum, the cerebellum and the spinal cord to one another, hosting relay nuclei for afferent and efferent signaling, and providing source nuclei for several neuromodulatory systems that impact central nervous system function. While the investigation of the brainstem with functional or structural magnetic resonance imaging has been hampered for years due to this brain structure's physiological and anatomical characteristics, the field has seen significant advances in recent years thanks to the broader adoption of ultrahigh-field (UHF) MRI scanning. In the present review, we focus on the advantages offered by UHF in the context of brainstem imaging, as well as the challenges posed by the investigation of this complex brain structure in terms of data acquisition and analysis. We also illustrate how UHF MRI can shed new light on the neuroanatomy and neurophysiology underlying different brainstem-based circuitries, such as the central autonomic network and neurotransmitter/neuromodulator systems, discuss existing and foreseeable clinical applications to better understand diseases such as chronic pain and Parkinson's disease, and explore promising future directions for further improvements in brainstem imaging using UHF MRI techniques.

Visual cortex and cerebellum hyperactivation during negative emotion picture stimuli in migraine patients

Migraines are a common and undertreated disease and often have psychiatric comorbidities; however, the abnormal mechanism of emotional processing in migraine patients has not been well clarified. This study sought to investigate the different brain functional activation to neutral, positive and negative emotional stimuli between migraine and healthy subjects. Twenty-six adults with migraines and 26 healthy adults, group-matched for sex and age, participated in this experiment. Although there were no significant differences between two groups during the viewing of positive affective pictures vs. neutral affective pictures, there were different activation patterns during the viewing of negative to neutral affective pictures in the two groups; the control group showed both increased and decreased activation patterns, while the migraine subjects showed only increased activation. Negative affective pictures elicited stronger activation than neutral affective pictures in migraineurs, which included the bilateral cerebellum anterior lobe/culmen, the bilateral lingual gyri, the bilateral precuneus and the left cuneus. Our data indicated that migraine patients were hypersensitive to negative stimuli, which might provide clues to aid in the understanding of the pathophysiology and psychiatric comorbidities of migraines.

The sensorimotor network dysfunction in migraineurs without aura: a resting-state fMRI study

Migraine is a common recurrent neurological disorder combining nausea, vomiting, and hypersensitivities to visual, auditory, olfactory and somatosensory stimuli. However, the dysfunction of the sensorimotor network in migraineurs has not been well clarified. In the present study, we evaluated the dysfunction of the sensorimotor network in 30 migraineurs without aura and in 31 controls by combining regional homogeneity (ReHo), amplitudes of low-frequency fluctuation (ALFF) and degree centrality (DC) analysis methods based on resting-state fMRI. A seed-based functional connectivity (FC) analysis was used to investigate whether the dysfunctional areas within the sensorimotor network exhibited abnormal FC with other brain areas. Compared to the controls, the migraineurs without aura exhibited significantly smaller ReHo, ALFF and DC values in the primary somatosensory cortex (S1) and right premotor cortex (PMC). The migraineurs showed weaker FC between the S1 and brain areas within the pain intensity and spatial discrimination pathways and trigemino-thalamo-cortical nociceptive pathway. We proposed that the dysfunction of the S1 and PMC and the decreased FC between the S1 and brain areas in migraineurs without aura may disrupt the discrimination of sensory features of pain and affect nociception pathways, and would be involved in the dysfunctional mechanism in migraine.

Visual-spatial training efficacy in children affected by migraine without aura: a multicenter study

Routinely in the clinical practice, children affected by migraine without aura (MwA) tend to exhibit severe and persistent difficulties within cognitive processes such as attention, memory, and visual-motor integration (VMI) skills. The aim of this study was to assess the visual-spatial and visual-motor abilities among a sample of children with MwA and the effects of a specific computerized training. The study population was composed of 84 patients affected by MwA (39 girls and 45 boys; mean age: 8.91±2.46 years), and they were randomly divided into two groups (group A and group B) comparable for age (P=0.581), gender (P=0.826), socioeconomic status (SES), migraine frequency (P=0.415), and intensity (P=0.323). At baseline (T0), the two groups were comparable for movement assessment battery for children (M-ABC) and VMI performances. After 6 months of treatment (T1), group A showed lower scores in the dexterity item of M-ABC test (P<0.001) and higher scores in M-ABC global performance centile (P<0.001) and total (P<0.001), visual (P=0.017), and motor (P<0.001) tasks of VMI test than group B. Moreover, at T1, group A showed higher scores in total (P<0.001) and motor (P<0.001) tasks of VMI test and in M-ABC global performance centile (P<0.001) and lower scores in the dexterity item of M-ABC test (P<0.001) than at T0. Group B showed, at T1, performances comparable to T0 for all evaluations. As reported by recent studies about alteration MwA among children in motor abilities, our study confirmed these difficulties and the efficacy of a specific software training, suggesting a new rehabilitative proposal in childhood.

Increased default mode network connectivity and increased regional homogeneity in migraineurs without aura

BACKGROUND

The precuneus/posterior cingulate cortex, which has been associated with pain sensitivity, plays a pivotal role in the default mode network. However, information regarding migraine-related alterations in resting-state brain functional connectivity in the default mode network and in local regional spontaneous neuronal activity is not adequate.

METHODS

This study used functional magnetic resonance imaging to acquire resting-state scans in 22 migraineurs without aura and in 22 healthy matched controls. Independent component analysis, a data-driven method, was used to calculate the resting-state functional connectivity of the default mode network in the patient and healthy control groups. Regional homogeneity (ReHo) was used to analyse the local features of spontaneous resting-state brain activity in the migraineurs without aura.

RESULTS

Compared with the healthy controls, migraineurs without aura showed increased functional connectivity in the left precuneus/posterior cingulate cortex within the default mode network and significant increase in ReHo values in the bilateral precuneus/posterior cingulate cortex, left pons and trigeminal nerve entry zone. In addition, functional connectivity was decreased between the areas with abnormal ReHo (using the peaks in the precuneus/posterior cingulate cortex) and other brain areas.

CONCLUSIONS

The abnormalities in the precuneus/posterior cingulate cortex suggest that migraineurs without aura may exhibit information transfer and multimodal integration dysfunction and that pain sensitivity and pian processing may also be affected.

Contribution of intravestibular sensory conflict to motion sickness and dizziness in migraine disorders

Migraine is associated with enhanced motion sickness susceptibility and can cause episodic vertigo [vestibular migraine (VM)], but the mechanisms relating migraine to these vestibular symptoms remain uncertain. We tested the hypothesis that the central integration of rotational cues (from the semicircular canals) and gravitational cues (from the otolith organs) is abnormal in migraine patients. A postrotational tilt paradigm generated a conflict between canal cues (which indicate the head is rotating) and otolith cues (which indicate the head is tilted and stationary), and eye movements were measured to quantify two behaviors that are thought to minimize this conflict: suppression and reorientation of the central angular velocity signal, evidenced by attenuation ("dumping") of the vestibuloocular reflex and shifting of the rotational axis of the vestibuloocular reflex toward the earth vertical. We found that normal and migraine subjects, but not VM patients, displayed an inverse correlation between the extent of dumping and the size of the axis shift such that the net "conflict resolution" mediated through these two mechanisms approached an optimal value and that the residual sensory conflict in VM patients (but not migraine or normal subjects) correlated with motion sickness susceptibility. Our findings suggest that the brain normally controls the dynamic and spatial characteristics of central vestibular signals to minimize intravestibular sensory conflict and that this process is disrupted in VM, which may be responsible for the enhance motion intolerance and episodic vertigo that characterize this disorder.

May headache triggered by odors be regarded as a differentiating factor between migraine and other primary headaches?

Objectives

The objective of this article is to characterize olfactory stimulation as a trigger of headaches attacks and differentiation between migraine and other primary headaches.

Participants and methods

The study was prospective and experimental, with comparison of groups. A total of 158 volunteers (73 men and 85 women) were diagnosed with primary headaches, according to the criteria of the International Classification of Headache Disorders, Third Edition (beta version) (ICHD-3β). The study was conducted by two examiners; one of them was assigned to diagnose the presence and type of primary headache, while the other was responsible for exposing the volunteers to odor and recording the effects of this exposure.

Results

Of the 158 volunteers with headache, there were 72 (45.6%) cases of migraine and 86 (54.4%) with other primary headaches. In both groups, there were differences in headache characteristics (χ2 = 4.132; p = 0.046). Headache attacks (25/72; 34.7%) and nausea (5/72; 6.9%) were triggered by odor only in patients with migraine, corresponding to 19.0% (30/158) of the sample, but in none with other primary headaches (χ2 = 43.78; p < 0.001). Headache occurred more often associated with nausea ( p = 0.146) and bilateral location ( p = 0.002) in migraineurs who had headache triggered by odor. Headache was triggered after 118 ± 24.6 min and nausea after 72.8 ± 84.7 min of exposure to odor.

Conclusions

The odor triggered headache attacks or nausea only in migraineurs. Therefore, headache triggered by odors may be considered a factor of differentiation between migraine and other primary headaches and this trigger seems very specific of migraine.

Brain plasticity and migraine transformation: fMRI evidences

INTRODUCTION

Chronification transforms episodic migraine into the pathologic chronic form. Biological characteristics of the migrainous brain progressively change, in predisposed subjects, under the repetition of external and internal stimuli. Modifications involve neurons, synapses, neurotransmitters, receptors, connectivity and pain control. f-MRI is a promising way to explore the still unclear biology of this progression. Areas covered: Data included were obtained from the most relevant and updated works available on PubMed about this topic. We summarized the pathophysiology of migraine chronification and of brain plasticity, and we described the different fMRI techniques and their main evidences about migraine transformation. Expert commentary: Functional-MRI has revealed many aspects regarding the peculiarity of the migrainous brain and its tendency toward chronicity but a series of questions are still open: What are the hallmarks of the predisposition to chronification? Which elements are the cause and which the consequence of this process?

Test-retest reliability of visual-evoked potential habituation

Objective

Habituation of visual-evoked potentials (VEPs) is typically described as deficient interictally in migraine patients, supposedly indicating altered cortical excitability. Use of this parameter for monitoring changes over time, e.g. under treatment, requires demonstration of test-retest reliability.

Methods

VEPs were recorded interictally in 41 episodic migraine patients and 40 controls. N75–P100 amplitudes were measured over six consecutive blocks of 75 VEPs each. Amplitude regression slopes and block ratios were used to quantify VEP habituation. Test-retest reliability was assessed over 15 minutes and two to three weeks.

Results

Controls showed significantly more negative VEP habituation slopes than migraine patients (−0.21 ± 0.40 vs. 0.04 ± 0.46 µV/block, p < 0.05). Results were similar for block ratios, though, in the migraine group, VEP habituation significantly increased from test to two- to three-week retest ( p < 0.05). In addition, VEP habituation test-retest correlations were mostly poor both in migraine patients and controls (intraclass correlation coefficients, 15 minutes: −0.13 to 0.30, two to three weeks: 0.07 to 0.59).

Conclusions

Deficient VEP habituation in migraine was confirmed. However, the test-retest reliability of VEP habituation was rather weak. Therefore, we suggest that VEP habituation should be used for evaluation of cortical excitability under treatment only at the group level and only when a control group with sham treatment is included.

Responsiveness of the autonomic nervous system during paced breathing and mental stress in migraine patients

Background

Migraine is a stress-related disorder, suggesting that there may be sympathetic hyperactivity in migraine patients. However, there are contradictory results concerning general sympathetic activation in migraine patients. To shed more light on the involvement of the autonomic nervous system (ANS) in migraine pathophysiology, we investigated cardiac and cardiovascular reactions during vagal (paced breathing) and sympathetic activation (mental stress test).

Methods

Heart rate variability parameters and skin conductance responses were recorded interictally in 22 episodic migraine patients without aura and 25 matched controls during two different test conditions. The paced breathing test consisted of a five-minute baseline, followed by two minutes of paced breathing (6 breathing cycles per minute) and a five-minute recovery phase. The mental stress test consisted of a five-minute baseline, followed by one minute of stress anticipation, three and a half minutes of mental stress and a five-minute recovery phase. Furthermore we measured blood pressure and heart rate once daily over 2 weeks. Subjects rated their individual current stress level and their stress level during paced breathing and during the mental stress test.

Results

There were no significant differences between migraine patients and controls in any of the heart rate variability parameters in either time domain or frequency domain analysis. However, all parameters showed a non-significant tendency for larger sympathetic activation in migraine patients. Also, no significant differences could be observed in skin conductance responses and average blood pressure. Only heart rates during the 2-week period and stress ratings showed significantly higher values in migraine patients compared to controls.

Conclusions

Generally there were no significant differences between migraine patients and controls concerning the measured autonomic parameters. There was a slight but not significant tendency in the migraine patients to react with less vagal and more sympathetic activation in all these tests, indicating a slightly changed set point of the autonomic system. Heart rate variability and blood pressure in migraine patients should be investigated for longer periods and during more demanding sympathetic activation.

Transcutaneous supraorbital neurostimulation in "de novo" patients with migraine without aura: the first Italian experience

BACKGROUND

Transcutaneous supraorbital neurostimulation (tSNS) has been recently found superior to sham stimulation for episodic migraine prevention in a randomized trial. We evaluated both the safety and efficacy of a brief period of tSNS in a group of patients with migraine without aura (MwoA).

METHODS

We enrolled 24 consecutive patients with MwoA experiencing a low frequency of attacks, which had never taken migraine preventive drugs in the course of their life. Patients performed a high frequency tSNS and were considered "compliant" if they used the tSNS for ≥ 2/3 of the total time expected. For this reason, four patients were excluded from the final statistical analysis. Primary outcome measures were the reduction migraine attacks and migraine days per month (p < 0.05). Furthermore, we evaluated the percentage of patients having at least 50% reduction of monthly migraine attacks and migraine days. Secondary outcome measures were the reduction of headache severity during migraine attacks and HIT-6 (Headache Impact Test) rating as well as in monthly intake of rescue medication (p < 0.05). Finally, compliance and satisfaction to treatment and potential adverse effects related to tSNS have been evaluated.

RESULTS

Between run-in and second month of tSNS treatment, both primary and secondary endpoints were met. Indeed, we observed a statistically significant decrease in the frequency of migraine attacks (p < 0.001) and migraine days (p < 0.001) per month. We also demonstrated at least 50% reduction of monthly migraine attacks and migraine days in respectively 81 and 75% of patients. Furthermore, a statistically significant reduction in average of pain intensity during migraine attacks (p = 0.002) and HIT-6 rating (p < 0.001) and intake of rescue medication (p < 0.001) has been shown. All patients showed good compliance levels and no relevant adverse events.

CONCLUSION

In patients experiencing a low frequency of attacks, significant improvements in multiple migraine severity parameters were observed following a brief period of high frequency tSNS. Therefore, tSNS may be considered a valid option for the preventive treatment of migraine attacks in patients who cannot or are not willing to take daily medications, or in whom low migraine frequency and/or intensity would not require pharmacological preventive therapies.

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.