Her versus his migraine: multiple sex differences in brain function and structure

A cross-sectional, multicenter survey of the prevalence and influencing factors for migraine in epilepsy

OBJECTIVES

Epilepsy and migraine are common chronic neurological disease. Epidemiologic studies and shared pathophysiology and treatment suggest that these two diseases overlap. However, migraine is often underestimated among patients with epilepsy. This study aimed to evaluate the prevalence of migraine and identify the related influencing factors among adult patients with epilepsy.

METHODS

Adult patients with epilepsy were recruited at the outpatient epilepsy clinic of 13 tertiary hospitals in China from February to September 2022. ID Migraine questionnaire was applied to evaluate for migraine. Both univariable and multivariable logistic regression models were used to explore the influencing factors of migraine.

RESULTS

A total of 1326 patients with epilepsy were enrolled in this study. The prevalence of migraine among patients with epilepsy was 19.2% (254/1326). In the multivariable analysis, being female (OR = 1.451, 95% CI: 1.068-1.975; p = 0.018), focal and focal to bilateral tonic-clonic seizures (OR = 1.583, 95% CI: 1.090-2.281; p = 0.015), and current seizure attack in the last 3 months (OR = 1.967, 95% CI: 1.282-3.063; p = 0.002) were the influencing factors for migraine. However, <10% of patients with epilepsy received analgesics for migraine.

SIGNIFICANCE

Approximately 20% of patients with epilepsy screened positive for migraine. Being female, focal and focal to bilateral tonic-clonic seizures, and current seizure attack in the last 3 months were the influencing factors for migraine. Neurologists should pay more attention to the screening and management of the migraine among patients with epilepsy in China.

PLAIN LANGUAGE SUMMARY

Epilepsy and migraine are common chronic neurological disease with shared pathophysiological mechanisms and therapeutic options. However, migraine is often underestimated among patients with epilepsy. This multicenter study aimed to evaluate the prevalence of migraine and current status of treatment. In this study, approximately 20% of patients with epilepsy screened positive for migraine. Female, focal and focal to bilateral tonic-clonic seizures, and current seizure attack in the last 3 months were identified as independent influencing factors for migraine. Despite the high prevalence, the treatment for migraine was not optimistic, neurologists should pay more attention to the screening and management of migraine.

A retrospective review of sex differences of white matter hyperintensities in brain MRI of patients with migraine

OBJECTIVES

The primary objective of this study was to evaluate the prevalence of white matter hyperintensities (WMHs) in patients who experience migraine and compare findings between adult male and female patients. Specific symptoms and comorbidities also were analyzed to determine whether they were associated with WMH prevalence or the sex of patients with migraine. We hypothesized that females would have a higher prevalence of WMHs, experience more frequent and more severe migraine headaches, and be more likely to have certain comorbidities associated with migraine than males.

BACKGROUND

An increased prevalence of WMHs in patients with migraine has been proposed, although this relation is not well-supported by data from population-based MRI studies. The difference in brain morphology between males and females is of research interest, and females in the general population appear to have a higher prevalence of WMHs. Sex differences and various comorbidities in patients with migraine relative to the number of WMHs on brain imaging have not been fully investigated.

METHODS

This was a cross-sectional study of 177 patients aged 18 years and older with a diagnosis of migraine who were seen in the Lehigh Valley Fleming Neuroscience Institute's Headache Center between January 1, 2000, and January 1, 2017. Patients' baseline characteristics were extracted from electronic medical records, including demographics, review of systems documentation, and brain imaging from MRI. Variables including headache severity, frequency of head pain, insomnia, and comorbidities (anxiety, depression, diabetes, hyperlipidemia, hypertension, and neck pain) also were analyzed for associations with the presence of WMHs.

RESULTS

Females were found to have a significantly higher number of WMHs than males (median 3 [IQR: 0-7] vs. 0 [IQR: 0-3], p = 0.023). Patients with WMHs were significantly more likely than those without WMHs to have hypertension (39.8% of patients with WMHs vs. 20.3% without WMHs, p = 0.011), constipation (20.9% vs. 8.3%, p = 0.034), and sleep disorder (55.7% vs. 37.3%, p = 0.022). Females with migraine were significantly more likely to experience constipation than males (20.0% vs. 2.9%, p = 0.015). None of the migraine characteristics studied (frequency, severity, presence of aura) were different between sexes, nor were they significantly associated with the presence of WMHs.

CONCLUSION

This study suggests that females with migraine may be more likely to have WMHs and experience constipation than males with migraine. Migraine frequency and severity were not different between sexes, nor were they significantly associated with the presence of WMHs. The findings of this study do not support a specific etiology of WMH development in individuals with migraine that differs from findings in the general population. Further studies are warranted.

Lactobacillus Plantarum intake mitigates neuropathic pain behavior via enhancing macrophage M2 polarization in a rat model of peripheral neuropathy

Pro-inflammatory macrophages (M1-polarized) play a crucial role in neuroinflammation and neuropathic pain following nerve injury. Redirecting macrophage polarization toward anti-inflammatory (M2-polarized) phenotypes offers a promising therapeutic strategy. Recognized for their anti-inflammatory and immunomodulatory properties, probiotics are becoming a focal point of research. This study investigated the effects of Lactobacillus plantarum on macrophage polarization, nerve protection, and neuropathic pain behavior following chronic constriction injury (CCI) of the median nerve. Rats received daily oral doses of L. plantarum for 28 days before and 14 days after CCI. Subsequently, behavioral and electrophysiological assessments were performed. The M1 marker CD86 levels, M2 marker CD206 levels, and concentrations of pro-inflammatory and anti-inflammatory cytokines in the injured median nerve were assessed. L. plantarum administration effectively reduced neuropathic pain behavior and the Firmicutes to Bacteroidetes ratio after CCI. Moreover, L. plantarum treatment increased serum short-chain fatty acids (SCFAs) levels, preserved myelination of the injured median nerve, and suppressed injury-induced discharges. In CCI rats treated with L. plantarum, there was a reduction in CD86 and pro-inflammatory cytokine levels, accompanied by an increase in CD206 and the release of anti-inflammatory cytokines. Furthermore, receptors for anti-inflammatory cytokines were localized on Schwann cells, and their expression was significantly upregulated in the injured nerves of CCI rats receiving L. plantarum. In conclusion, L. plantarum shifts macrophage phenotypes from M1 to M2 by promoting the production of SCFAs and enhancing the release of anti-inflammatory cytokines. Ultimately, this process preserves nerve fiber integrity and impedes the onset of neuropathic pain.

Association between migraine and the risk of vascular dementia: A nationwide longitudinal study in South Korea

OBJECTIVE

We aimed to examine the potential association between migraine and vascular dementia (VaD) using a nationwide population database.

BACKGROUND

Migraine and VaD showed similar structural and functional changes in pathophysiology process and shared common risk factors, However, whether migraine prevalence increases VaD incidence remains controversial.

METHODS

This retrospective population-based cohort study used the medical records from the Korean National Health Insurance System database. Migraine (G43) was defined by using the Tenth Revision of the International Classification of Diseases code. More than two migraine diagnoses at least 3 months apart were defined as "chronic migraine". Cox proportional hazards model estimated hazard ratios (HRs) of VaD for group comparisons.

RESULTS

We included 212,836 patients with migraine and 5,863,348 individuals without migraine. During 10 years of follow-up, 3,914 (1.8%) and 60,258 (1.0%) patients with and without migraine, respectively, were newly diagnosed with VaD. After adjustment, patients with migraine showed a 1.21-fold higher risk of VaD than those without migraine (HR = 1.21; 95% confidence interval (CI): 1.17-1.25). Patients with chronic migraine showed a higher cumulative incidence of VaD than those with episodic migraine. The adjusted HR for the VaD incidence with migraine was higher in: (1) patients aged <65 years; (2) women; (3) patients without hypertension, diabetes, or atrial fibrillation; and (4) non-smokers.

CONCLUSION

Migraine is associated with an increased risk of VaD, particularly in chronic migraine patients. Incidence of VaD in the setting of migraine may have distinct pathophysiology from that of VaD with traditional cardiovascular risks.

[Gender-specific results of the Dresden children and adolescents headache program DreKiP]

BACKGROUND

Girls and women are more frequently affected by headache than boys and men. The influence of gender on the effectiveness of headache therapies has so far been hardly investigated. We examined gender differences in the outpatient multimodal Dresden Child and Adolescent Headache Program DreKiP.

METHODS

We treated 140 patients with primary headache in a 15-hour structured group program. At baseline (T0) and six (T1) and twelve months (T2) after the end of the program, data on headache-related limitation of daily activities (PedMIDAS) as well as headache frequency, intensity, and pain-related disability (P-PDI) were collected. Retrospectively, these data were analyzed separately for girls and boys.

RESULTS

For 91 patients (9-19 years, median = 15; 71.4 % female) data were available for at least two measurement time points. Girls showed significantly higher headache frequency than boys at all time points (median headache days/last three months at T0: ♀ 43, ♂ 20; T1: ♀ 32, ♂ 12; T2: ♀ 28, ♂ 9) as well as numerically higher headache-related limitation of daily life. There were significant effects over time with a decrease in headache frequency (F (2.88) = 5.862; p = 0.004) and improvement in daily functioning (F (2.92) = 5.340; p = 0.006). There was no gender-specific treatment response.

DISCUSSION

The DreKiP therapy shows effects in girls and boys with primary headache. Higher headache frequencies and everyday life restrictions in girls may have hormonal but also psychosocial causes and should be addressed in educational measures.

Contralateral acupuncture for migraine without aura: a randomized trial protocol with multimodal MRI

Introduction

Migraine is a common clinical disorder, ranks as the second most disabling disease worldwide, and often manifests with unilateral onset. Contralateral acupuncture (CAT), as a classical acupuncture method, has been proven to be effective in the treatment of migraine without aura (MWoA). However, its neural mechanisms have not been investigated using multimodal magnetic resonance imaging (MRI).

Methods and analysis

In this multimodal neuroimaging randomized trial, a total of 96 female MWoA participants and 30 female healthy controls (HCs) will be recruited. The 96 female MWoA participants will be randomized into three groups: Group A (CAT group), Group B [ipsilateral acupuncture (IAT) group], and Group C (sham CAT group) in a 1:1:1 allocation ratio. Each group will receive 30 min of treatment every other day, three times a week, for 8 weeks, followed by an 8-week follow-up period. The primary outcome is the intensity of the migraine attack. Data will be collected at baseline (week 0), at the end of the 8-week treatment period (weeks 1-8), and during the 8-week follow-up (weeks 9-16). Adverse events will be recorded. Multimodal MRI scans will be conducted at baseline and after 8-week treatment.

Discussion

This study hypothesized that CAT may treat MWoA by restoring pathological alterations in brain neural activity, particularly by restoring cross-integrated functional connectivity with periaqueductal gray (PAG) as the core pathological brain region. The findings will provide scientific evidence for CAT in the treatment of MWoA.

Ethics and dissemination

The Medical Ethics Committee of the Second Affiliated Hospital of Yunnan University of Chinese Medicine has given study approval (approval no. 2022-006). This trial has been registered with the Chinese Clinical Trials Registry (registration no. ChiCTR2300069456). Peer-reviewed papers will be used to publicize the trial's findings.

Clinical trial registration

https://clinicaltrials.gov/, identifier ChiCTR2300069456.

Sex differences in cerebral blood flow among adolescents with bipolar disorder

BACKGROUND

Abnormalities in cerebral blood flow (CBF) are common in bipolar disorder (BD). Despite known differences in CBF between healthy adolescent males and females, sex differences in CBF among adolescents with BD have never been studied.

OBJECTIVE

To examine sex differences in CBF among adolescents with BD versus healthy controls (HC).

METHODS

CBF images were acquired using arterial spin labeling (ASL) perfusion magnetic resonance imaging (MRI) in 123 adolescents (72 BD: 30M, 42F; 51 HC: 22M, 29F) matched for age (13-20 years). Whole brain voxel-wise analysis was performed in a general linear model with sex and diagnosis as fixed factors, sex-diagnosis interaction effect, and age as a covariate. We tested for main effects of sex, diagnosis, and their interaction. Results were thresholded at cluster forming p = 0.0125, with posthoc Bonferroni correction (p = 0.05/4 groups).

RESULTS

A main effect of diagnosis (BD > HC) was observed in the superior longitudinal fasciculus (SLF), underlying the left precentral gyrus (F =10.24 (3), p < 0.0001). A main effect of sex (F > M) on CBF was detected in the precuneus/posterior cingulate cortex (PCC), left frontal and occipital poles, left thalamus, left SLF, and right inferior longitudinal fasciculus (ILF). No regions demonstrated a significant sex-by-diagnosis interaction. Exploratory pairwise testing in regions with a main effect of sex revealed greater CBF in females with BD versus HC in the precuneus/PCC (F = 7.1 (3), p < 0.01).

CONCLUSION

Greater CBF in female adolescents with BD versus HC in the precuneus/PCC may reflect the role of this region in the neurobiological sex differences of adolescent-onset BD. Larger studies targeting underlying mechanisms, such as mitochondrial dysfunction or oxidative stress, are warranted.

Aberrant brain functional hubs and causal effective connectivity in menstrually-related and non-menstrually-related migraine without aura

Background

Menstrual migraine without aura (MRM) is common in female migraineurs and is closely related to cerebral functional abnormalities. However, whether the whole brain networks and directional functional connectivity of MRM patients are altered remains unclear. The purpose of this study was to detect the alterations of resting-state functional networks and directional functional connectivity between MRM and non-menstrual migraine without aura (NMM) patients using functional magnetic resonance imaging (fMRI) with degree centrality (DC) and Granger causality analysis (GCA) methods.

Methods

In this retrospective and cross-sectional study, 45 MRM and 40 NMM patients (matched in age, gender, and years of education) were recruited in the study between May 2018 and June 2022. All participants had undergone resting-state fMRI scanning at the Neurology and Pain Outpatient Department of Nanjing First Hospital. Their brain functions were analyzed in terms of DC and GCA, with the significant threshold at voxel level P<0.01 and cluster level P<0.05, Gaussian random field corrected. Correlation analysis was adopted to assess the relationships between the fMRI results and clinical features (P<0.05, Bonferroni corrected).

Results

Compared with those in the NMM group, MRM patients showed decreased DC in the right insula (T=-4.253). Using the right insula as the seed region, patients with MRM demonstrated enhanced effective connectivity from the right insula to the ipsilateral middle temporal gyrus (T=4.138) and contralateral superior temporal gyrus (T=3.523). Furthermore, the MRM group also showed decreased effective connectivity from several brain regions to the right insula, which included the right inferior occipital gyrus (T=-4.498), left middle frontal gyrus (T=-4.879), right precuneus (T=-4.644), and left inferior parietal gyrus (T=-4.113). The average Self-rating Anxiety Scale score of the MRM group was significantly higher than that of the NMM group [P=0.032, 95% confidence interval (CI): 0.363-7.761]. In the MRM group, disease duration was negatively correlated with the mean value of DC in right insula (r=-0.428, P=0.01).

Conclusions

The present research demonstrated that patients with MRM have disruption in insula resting-state functional networks. Disrupted networks contained regions associated with cognitive processes, emotional perception, and migraine attack in MRM patients. These results may improve our comprehension of the neuromechanism of menstrually-related migraine.

Volumetric alteration of brainstem in female migraineurs with and without aura

BACKGROUND AND AIM

Brainstem descending modulatory circuits have been postulated to be involved in migraine. Differences in brainstem volume between migraineurs and healthy controls have been demonstrated in previous research, nevertheless, the effect of migraine aura on brainstem volume is still uncertain. The aim of this study was to investigate the brainstem volume in migraineurs and examine the effect of migraine aura on brainstem volume.

METHODS

Our study included 90 female migraine patients without white matter lesions. (29 migraine patients with aura (MwA) and 61 migraine patients without aura (MwoA) and 32 age-matched female healthy controls (HC). Using the FreeSurfer image analysis suite, the volumes of the entire brainstem and its subfields (medulla, pons, and midbrain) were measured and compared between migraine subgroups (MwA vs. MwoA) and the healthy control group. The possible effects of migraine characteristics (i.e., disease duration and migraine attack frequency) on brainstem volume were also investigated.

RESULTS

Migraineurs had greater medulla volume (MwoA 3552 ± 459 mm3, MwA 3424 ± 448 mm3) than healthy controls (3236 ± 411 mm3). Statistically, MwA vs. HC p = 0.040, MwoA vs. HC p = 0.002, MwA vs. MwoA p = 0.555. A significant positive correlation was found between disease duration and the volume of medulla in the whole migraine group (r = 0.334, p = 0.001). Neither the whole brainstem nor its subfields were significantly different in volume between migraine subgroups.

CONCLUSION

Brainstem volume changes in migraine are mainly localized to the medulla and not specific to the presence of aura.

Comprehensive review on sexual dimorphism to improve scalp acupuncture in nervous system disease

BACKGROUND

With the development of modern medicine, the Traditional Chinese Medicine (TCM) combined with western medicine began to be produced and applied. Scalp acupuncture (SA) as a Chinese medicine based on neurological theory, has a great advantage compared with TCM in the treatment of nervous system diseases.

METHOD

In this paper, we analyze the physiological and pathological manifestations of sexual dimorphism (SD) to illustrate the necessity of SD treatment. In addition, we review the factors that can affect SD and analyze in physiological structure, function, and pathological neurons. Diseases (pathological basis, pathological manifestations, and incidence) and factors leading to gender differences, which to analyze the possibility of gender differences in SA.

RESULT

Furthermore, we creatively a new insight of SD-SA and provide the complete SD treatment cases on the basis of the existing SA in different kinds of diseases including stroke, migraine, attention deficit hyperactivity disorder (ADHD), and depression.

CONCLUSION

In summary, we believe that it is feasible to improve the clinical effectiveness of SA, which is able to promote the development of SA, and then provides an actionable evidence for the promotion of precision medicine in the future.

Exploring the Connection between Migraines and Pregnancy: The Impact of Physical Activity on Symptom Management

Migraine is a prevalent neurological disorder that significantly impacts the quality of life for affected individuals. The pathogenesis behind migraines is not yet fully understood, but hormonal changes, especially fluctuations in, estrogen and progesterone levels, have a significant role in the susceptibility of women to migraines. Pregnancy introduces a unique set of challenges for women who experience migraines, as they must navigate the complexities of managing their condition while safeguarding the health of both them and their unborn child. Pharmacological options for treating migraines during pregnancy are limited, and, therefore, there is a growing interest in exploring alternative approaches to migraine symptom relief and management. Physical activity during pregnancy provides a range of benefits, and it has gained attention as a potentially valuable tool for alleviating migraine symptoms in pregnant patients. This review explores the intricate relationship between migraines and pregnancy, emphasizing how physical activity and other alternative approaches may influence the frequency, severity, and overall experience of migraines during pregnancy. Through collaboration with healthcare providers and the adoption of personalized management strategies, women can strike a balance that supports both their own well-being and the healthy development of their unborn child. By examining existing research and emerging insights, we aim to provide a comprehensive understanding of the potential benefits and considerations of incorporating physical activity and other treatment options into migraine management strategies for pregnant women. Further research is needed to elucidate the specific mechanisms linking migraines, pregnancy, and physical activity, enabling the development of more targeted interventions and guidelines.

Molecular mechanisms of hormones implicated in migraine and the translational implication for transgender patients

Migraine is a primary headache disorder recognized by the World Health Organization as one of the most poorly understood and debilitating neurological conditions impacting global disability. Chronic pain disorders are more frequently diagnosed among cisgender women than men, suggesting that female sex hormones could be responsible for mediating chronic pain, including migraine and/or that androgens can be protective. This review discusses the major gonadal hormones, estrogens, progesterone, and testosterone in the context of molecular mechanisms by which they play a role in migraine pathophysiology. In addition, the literature to date describing roles of minor sex hormones including prolactin, luteinizing hormone, follicular stimulating hormone, and gonadotropin releasing hormone in migraine are presented. Because transgender and gender non-conforming (trans*) individuals are an underserved patient population in which gender-affirming sex hormone replacement therapy (HRT) is often medically necessary to align biological sex with gender identity, results from cisgender patient populations are discussed in the context of these major and minor sex hormones on migraine incidence and management in trans* patients.

Global, regional, and national epidemiology of migraine and tension-type headache in youths and young adults aged 15-39 years from 1990 to 2019: findings from the global burden of disease study 2019

BACKGROUND

In recent years, headache disorders have garnered significant attention as a pressing global health issue. This concern is especially pronounced in low- to middle-income countries and exhibits a notable increase in prevalence among adolescents and young adults. Such a surge in these disorders has invariably diminished the quality of life for affected individuals. Despite its global impact, comprehensive studies exploring the ramifications of headache disorders in the younger population remain scant. Our study endeavored to quantify the global prevalence of headache disorders in individuals between the ages of 15 and 39, over a three-decade span from 1990 to 2019.

METHODS

Our study, conducted from 1990 to 2019, evaluated the impact of headache disorders, specifically migraines and tension-type headaches (TTH), in 204 different countries and territories. This comprehensive assessment included a detailed analysis of incidence rates, prevalence, and disability-adjusted life-years (DALYs) across various demographics such as age, gender, year, geographical location, and Socio-demographic Index (SDI).

RESULTS

In 2019, there were an estimated 581,761,847.2 migraine cases globally (95% UI: 488,309,998.1 to 696,291,713.7), marking a 16% increase from 1990. Concurrently, TTH cases numbered at 964,808,567.1 (95% UI: 809,582,531.8 to 1,155,235,337.2), reflecting a 37% rise since 1990. South Asia reported the highest migraine prevalence with 154,490,169.8 cases (95% UI: 130,296,054.6 to 182,464,065.6). High SDI regions exhibited the most substantial migraine prevalence rates both in 1990 (22,429 per 100,000 population) and 2019 (22,606 per 100,000 population). Among the five SDI classifications, the middle SDI region recorded the highest tally of TTH cases in both 1990 (210,136,691.6 cases) and 2019 (287,577,250 cases). Over the past 30 years, East Asia experienced the most pronounced surge in the number of migraine cases. On the whole, there was a discernible positive correlation between the disease burden of migraine and TTH and the SDI.

CONCLUSION

Migraine and TTH represent formidable challenges in global health. The intensity of their impact exhibits marked disparities across nations and is distinctly elevated among women, individuals within the 30-39 age bracket, and populations characterized by a high SDI. The results of our research emphasize the imperative of assimilating migraine and TTH management into contemporary healthcare paradigms. Such strategic integration holds the potential to amplify public cognizance regarding pertinent risk factors and the spectrum of therapeutic interventions at hand.

Menstrually-related migraine shapes the structural similarity network integration of brain

Menstrually-related migraine (MM) is a primary migraine in women of reproductive age. The underlying neural mechanism of MM was still unclear. In this study, we aimed to reveal the case-control differences in network integration and segregation for the morphometric similarity network of MM. Thirty-six patients with MM and 29 healthy females were recruited and underwent MRI scanning. The morphometric features were extracted in each region to construct the single-subject interareal cortical connection using morphometric similarity. The network topology characteristics, in terms of integration and segregation, were analyzed. Our results revealed that, in the absence of morphology differences, disrupted cortical network integration was found in MM patients compared to controls. The patients with MM showed a decreased global efficiency and increased characteristic path length compared to healthy controls. Regional efficiency analysis revealed the decreased efficiency in the left precentral gyrus and bilateral superior temporal gyrus contributed to the decreased network integration. The increased nodal degree centrality in the right pars triangularis was positively associated with the attack frequency in MM. Our results suggested MM would reorganize the morphology in the pain-related brain regions and reduce the parallel information processing capacity of the brain.

Sex-related differences in migraine clinical features by frequency of occurrence: a cross-sectional study

OBJECTIVES

The sex-related differences of migraine hold clinical relevance to achieve a better diagnosis and treatment. The purpose of this cross-sectional study was to evaluate sex-related differences in migraine features, the impact, and health care resources for people who suffer from episodic migraine (EM) and chronic migraine (CM).

METHODS

184 patients (72 % women; 61.4 % with EM; mean (SD) age of 38.7 (10.4) years) were assessed through the Migraine Disability Assessment, the Short Form 36 Health Survey, the Beck Depression Inventory II and the State-Trait Anxiety Inventory. Additionally, medication intake and medical assistance were recorded. Multivariate analyses were performed, stratifying by frequency of occurrence (EM and CM) and sex (men and women).

RESULTS

The results showed that women presented a greater number of symptoms (p=0.03), pain intensity (p<0.01), pain duration (p=0.03), disability (p=0.01), amount of symptomatic medication (p=0.04) and medical visits (p=0.001), as well as a worse physical role (p=0.004) than men with EM. However, no significant differences between them were found for CM (p>0.05). Moreover, it was identified that there was a significant increase in medication intake among people with CM compared to EM (p<0.001). It is worth noting that there were no significant differences by diagnosis and sex in emotional status (p>0.05).

CONCLUSIONS

Migraine features, impact and health care resources were greater in women than men with EM; yet no significant differences between them were found for CM. The findings of the present study may contribute to a better diagnosis and treatment response in people with migraines.

The influence of sex steroid treatment on insular connectivity in gender dysphoria

BACKGROUND

Sex-specific differences in brain connectivity were found in various neuroimaging studies, though little is known about sex steroid effects on insular functioning. Based on well-characterized sex differences in emotion regulation, interoception and higher-level cognition, gender-dysphoric individuals receiving gender-affirming hormone therapy represent an interesting cohort to investigate how sex hormones might influence insular connectivity and related brain functions.

METHODS

To analyze the potential effect of sex steroids on insular connectivity at rest, 11 transgender women, 14 transgender men, 20 cisgender women, and 11 cisgender men were recruited. All participants underwent two magnetic resonance imaging sessions involving resting-state acquisitions separated by a median time period of 4.5 months and also completed the Bermond-Vorst alexithymia questionnaire at the initial and final examination. Between scans, transgender subjects received gender-affirming hormone therapy.

RESULTS

A seed based functional connectivity analysis revealed a significant 2-way interaction effect of group-by-time between right insula, cingulum, left middle frontal gyrus and left angular gyrus. Post-hoc tests demonstrated an increase in connectivity for transgender women when compared to cisgender men. Furthermore, spectral dynamic causal modelling showed reduced effective connectivity from the posterior cingulum and left angular gyrus to the left middle frontal gyrus as well as from the right insula to the left middle frontal gyrus. Alexithymia changes were found after gender-affirming hormone therapy for transgender women in both fantasizing and identifying.

CONCLUSION

These findings suggest a considerable influence of estrogen administration and androgen suppression on brain networks implicated in interoception, own-body perception and higher-level cognition.

Global, regional, and national time trends in incidence for migraine, from 1990 to 2019: an age-period-cohort analysis for the GBD 2019

BACKGROUND

The majority of epidemiological studies on migraine have been conducted in a specific country or region, and there is a lack of globally comparable data. We aim to report the latest information on global migraine incidence overview trends from 1990 to 2019.

METHODS

In this study, the available data were obtained from the Global Burden of Disease 2019. We present temporal trends in migraine for the world and its 204 countries and territories over the past 30 years. Meanwhile, an age-period-cohort model be used to estimate net drifts (overall annual percentage change), local drifts (annual percentage change in each age group), longitudinal age curves (expected longitudinal age-specific rate), and period (cohort) relative risks.

RESULTS

In 2019, the global incidence of migraine increased to 87.6 million (95% UI: 76.6, 98.7), with an increase of 40.1% compared to 1990. India, China, United States of America, and Indonesia had the highest number of incidences, accounting for 43.6% of incidences globally. Females experienced a higher incidence than males, the highest incidence rate was observed in the 10-14 age group. However, there was a gradual transition in the age distribution of incidence from teenagers to middle-aged populations. The net drift of incidence rate ranged from 3.45% (95% CI: 2.38, 4.54) in high-middle Socio-demographic Index (SDI) regions to -4.02% (95% CI: -4.79, -3.18) in low SDI regions, 9 of 204 countries showed increasing trends (net drifts and its 95% CI were > 0) in incidence rate. The age-period-cohort analysis results showed that the relative risk of incidence rate generally showed unfavorable trends over time and in successively birth cohorts among high-, high-middle-, and middle SDI regions, but low-middle- and low-SDI regions keep stable.

CONCLUSIONS

Migraine is still an important contributor to the global burden of neurological disorders worldwide. Temporal trends in migraine incidence are not commensurate with socioeconomic development and vary widely across countries. Both sexes and all age groups should get healthcare to address the growing migraine population, especially adolescents and females.

Sex differences in migraine attack characteristics: A longitudinal E-diary study

OBJECTIVE

In this prospective cohort study, characteristics of perimenstrual and non-perimenstrual migraine attacks in women were compared with migraine attacks in men.

BACKGROUND

Women report longer migraine attacks and more accompanying symptoms than men in cross-sectional questionnaire studies, but this has not been confirmed in longitudinal studies. Supposed differences could result from different characteristics specific to perimenstrual migraine attacks, or of attacks in women in general.

METHODS

This cohort study was performed among patients with migraine who were treated at the Leiden Headache Clinic. We assessed differences in migraine attack characteristics between men and women who were prospectively followed by a previously validated electronic headache diary. The primary outcome was "attack" duration. Differences between perimenstrual (Days -2 to +3 of the menstrual cycle) and non-perimenstrual attacks in women versus attacks in men were corrected for age, chronic migraine, and medication overuse headache.

RESULTS

A total of 1347 women and 284 men were included, reflecting the preponderance of women in migraine prevalence. Crude median (first and third quartile [Q1-Q3]) attack duration in men was 32.1 [17.7-53.6] h, compared to 36.7 [21.9-62.4] h for non-perimenstrual migraine attacks and 44.4 [17.9-79.0] h for perimenstrual migraine attacks in women. After correction for confounding, perimenstrual migraine attacks were 1.62 (95% confidence interval [CI] 1.47-1.79; p < 0.001) and non-perimenstrual 1.15 (95% CI 1.05-1.25; p = 0.003) times longer compared to migraine attacks in men. The mean relapse percentage in men was 9.2%, compared to 12.6% for non-perimenstrual migraine attacks, and 15.7% for perimenstrual migraine attacks. Relapse risk was greater for perimenstrual (odds ratio [OR] 2.39, 95% CI 1.93-2.95; p < 0.001), but not for non-perimenstrual (OR 1.18, 95% CI 0.97-1.45; p = 0.060) attacks. Migraine attacks in women were more often accompanied by photophobia, phonophobia, and nausea, but less often aura.

CONCLUSION

Compared to attacks in men, both perimenstrual and non-perimenstrual migraine attacks are of longer duration and are more often accompanied by associated symptoms. A sex-specific approach to migraine treatment and research is needed.

Functional magnetic resonance imaging of headache: Issues, best-practices, and new directions, a narrative review

OBJECTIVE

To ensure readers are informed consumers of functional magnetic resonance imaging (fMRI) research in headache, to outline ongoing challenges in this area of research, and to describe potential considerations when asked to collaborate on fMRI research in headache, as well as to suggest future directions for improvement in the field.

BACKGROUND

Functional MRI has played a key role in understanding headache pathophysiology, and mapping networks involved with headache-related brain activity have the potential to identify intervention targets. Some investigators have also begun to explore its use for diagnosis.

METHODS/RESULTS

The manuscript is a narrative review of the current best practices in fMRI in headache research, including guidelines on transparency and reproducibility. It also contains an outline of the fundamentals of MRI theory, task-related study design, resting-state functional connectivity, relevant statistics and power analysis, image preprocessing, and other considerations essential to the field.

CONCLUSION

Best practices to increase reproducibility include methods transparency, eliminating error, using a priori hypotheses and power calculations, using standardized instruments and diagnostic criteria, and developing large-scale, publicly available datasets.

Migraine and thyroid dysfunction: Co-occurrence, shared genes and biological mechanisms

BACKGROUND AND PURPOSE

Migraine and thyroid dysfunction, particularly hypothyroidism, are common medical conditions and are known to have high heritability. Thyroid function measures, thyroid stimulating hormone (TSH) and free thyroxine (fT4), are also known to be genetically influenced. Although observational epidemiological studies report an increased co-occurrence of migraine and thyroid dysfunction, a clear and combined interpretation of the findings is currently lacking. A narrative review is provided of the epidemiological and genetic association evidence linking migraine, hypothyroidism, hyperthyroidism and thyroid hormones TSH and fT4.

METHODS

An extensive literature search was conducted in the PubMed database for epidemiological, candidate gene and genome-wide association studies using the terms migraine, headache, thyroid hormones, TSH, fT4, thyroid function, hypothyroidism and hyperthyroidism.

RESULTS

Epidemiological studies suggest a bidirectional relationship between migraine and thyroid dysfunction. However, the nature of the relationship remains unclear, with some studies suggesting migraine increases the risk for thyroid dysfunction whilst other studies suggest the reverse. Early candidate gene studies have provided nominal evidence for MTHFR and APOE, whilst more recently genome-wide association studies have provided robust evidence for THADA and ITPK1 being associated with both migraine and thyroid dysfunction.

CONCLUSIONS

These genetic associations improve our understanding of the genetic relationship between migraine and thyroid dysfunction, provide an opportunity to develop biomarkers to identify migraine patients most likely to benefit from thyroid hormone therapy, and indicate that further cross-trait genetic studies have excellent potential to provide biological insight into their relationship and inform clinical interventions.

Migraine Type-Dependent Patterns of Brain Activation After Facial and Intranasal Trigeminal Stimulation

In migraine, the trigeminal nerve is intimately involved in the pathophysiology of the disease. We hypothesized that alterations in the sensory trigeminal activation in migraine would be reflected by EEG-derived event-related potentials (ERP). We aimed to investigate differences in the temporal and spatial processing of trigeminal stimuli between interictal migraine patients and healthy subjects. ERP to trigeminal stimuli were recorded at 128-channels to allow localization of their cortical sources with high temporal resolution. Seventeen patients with episodic migraine without aura, 17 subjects with episodic migraine with aura, and 17 healthy subjects participated in the study. The first branch of the trigeminal nerve was stimulated using intranasal chemical (CO₂), cutaneous electrical, and cutaneous mechanical (air puff) stimuli. Analyses were performed with regard to micro-state segmentation, ERP source localization, and correlation with the patients' clinical characteristics. Topographical assessments of EEG configurations were associated with the pathological condition. The source analysis revealed altered trigeminal-sensory response patterns in the precuneus, temporal pole, and cerebellum for both migraine groups during the interictal phase. The estimated current source density was positively correlated with migraine disease duration, indicating brain functional and structural changes as a consequence of the disease. Hyperactivity of the cerebellar posterior lobe was observed as a specific trigeminal response of migraine patients with aura. In conclusion, our results suggest the presence of brain changes accompanying the advancement of migraine as an expression of dysfunctional central pain processing. Hence, we identified EEG patterns in response to mechano-/chemosensory stimuli that can serve as biomarkers of migraine.

The Role of fMRI in Drug Development: An Update

Functional magnetic resonance imaging (fMRI) of the brain is a technology that holds great potential for increasing the efficiency of drug development for the central nervous system (CNS). In preclinical studies and both early- and late-phase human trials, fMRI has the potential to improve cross-species translation of drug effects, help to de-risk compounds early in development, and contribute to the portfolio of evidence for a compound's efficacy and mechanism of action. However, to date, the utilization of fMRI in the CNS drug development process has been limited. The purpose of this chapter is to explore this mismatch between potential and utilization. This chapter provides introductory material related to fMRI and drug development, describes what is required of fMRI measurements for them to be useful in a drug development setting, lists current capabilities of fMRI in this setting and challenges faced in its utilization, and ends with directions for future development of capabilities in this arena. This chapter is the 5-year update of material from a previously published workshop summary (Carmichael et al., Drug DiscovToday 23(2):333-348, 2018).

Impaired Inter-Hemispheric Functional Connectivity during Resting State in Female Patients with Migraine

The application of voxel-mirrored homotopic connectivity (VMHC) analysis to study the central mechanism of migraine has been limited. Furthermore, little is known about inter-hemispheric functional connectivity (FC) alterations during resting state in female patients with migraine. This study aimed to investigate potential interictal VMHC impairments in migraine without aura (MwoA) patients and the relationship between connectivity alterations and clinical parameters. Resting-state functional magnetic resonance imaging data and clinical information were acquired from 43 female MwoA patients and 43 matched healthy controls. VMHC analysis was used to compare differences between these two groups, and brain regions showing significant differences were chosen as a mask to perform a seed-based FC group comparison. Subsequent correlation analysis was conducted to explore the relationship between abnormal inter-hemispheric FC and clinical data. Compared with healthy controls, female MwoA patients revealed significantly decreased VMHC in the bilateral cerebellum; cuneus; and lingual, middle occipital, precentral and postcentral gyri. Seed-based FC analysis indicated disrupted intrinsic connectivity in the cerebellum, and default mode, visual and sensorimotor network. These VMHC and FC abnormalities were negatively correlated with clinical indexes including duration of disease, migraine days and visual analogue scale. These inter-hemispheric FC impairments and correlations between abnormal VMHC and FC and clinical scores may improve our understanding of the central mechanism of female-specific migraine.

Involvement of the cerebellum in migraine

Migraine is a disabling neurological disease characterized by moderate or severe headaches and accompanied by sensory abnormalities, e.g., photophobia, allodynia, and vertigo. It affects approximately 15% of people worldwide. Despite advancements in current migraine therapeutics, mechanisms underlying migraine remain elusive. Within the central nervous system, studies have hinted that the cerebellum may play an important sensory integrative role in migraine. More specifically, the cerebellum has been proposed to modulate pain processing, and imaging studies have revealed cerebellar alterations in migraine patients. This review aims to summarize the clinical and preclinical studies that link the cerebellum to migraine. We will first discuss cerebellar roles in pain modulation, including cerebellar neuronal connections with pain-related brain regions. Next, we will review cerebellar symptoms and cerebellar imaging data in migraine patients. Lastly, we will highlight the possible roles of the neuropeptide calcitonin gene-related peptide (CGRP) in migraine symptoms, including preclinical cerebellar studies in animal models of migraine.

Genetic Overlap Analysis Identifies a Shared Etiology between Migraine and Headache with Type 2 Diabetes

Migraine and headache frequently co-occur with type 2 diabetes (T2D), suggesting a shared aetiology between the two conditions. We used genome-wide association study (GWAS) data to investigate the genetic overlap and causal relationship between migraine and headache with T2D. Using linkage disequilibrium score regression (LDSC), we found a significant genetic correlation between migraine and T2D (rg = 0.06, p = 1.37 × 10−5) and between headache and T2D (rg = 0.07, p = 3.0 × 10−4). Using pairwise GWAS (GWAS-PW) analysis, we identified 11 pleiotropic regions between migraine and T2D and 5 pleiotropic regions between headache and T2D. Cross-trait SNP meta-analysis identified 23 novel SNP loci (Pmeta < 5 × 10−8) associated with migraine and T2D, and three novel SNP loci associated with headache and T2D. Cross-trait gene-based overlap analysis identified 33 genes significantly associated (Pgene-based < 3.85 × 10−6) with migraine and T2D, and 11 genes associated with headache and T2D, with 7 genes (EHMT2, SLC44A4, PLEKHA1, CFDP1, TMEM170A, CHST6, and BCAR1) common between them. There was also a significant overlap of genes nominally associated (Pgene-based < 0.05) with both migraine and T2D (Pbinomial-test = 2.83 × 10−46) and headache and T2D (Pbinomial-test = 4.08 × 10−29). Mendelian randomisation (MR) analyses did not provide consistent evidence for a causal relationship between migraine and T2D. However, we found headache was causally associated (inverse-variance weighted, ORIVW = 0.90, Pivw = 7 × 10−3) with T2D. Our findings robustly confirm the comorbidity of migraine and headache with T2D, with shared genetically controlled biological mechanisms contributing to their co-occurrence, and evidence for a causal relationship between headache and T2D.

Brain structural and functional changes during menstrual migraine: Relationships with pain

Objectives

Menstrual migraine (MM) is a special type of migraine associated with the ovarian cycle, which imposes a marked burden on female patients. However, the pathogenesis of MM is not completely understood. We investigated gray matter volume (GMV) and functional connectivity (FC) alterations in patients with MM to explore whether there are changes in resting-state FC (rsFC) in brain regions with structural GMV abnormalities and investigated their relevance to pain and concomitant symptoms.

Methods

Seventy-five patients with MM and 54 female healthy controls underwent functional magnetic resonance imaging and examination. The patients completed a patient’s headache diary, which included the frequency of migraine attacks, a visual analog scale for pain, a self-rating anxiety scale, and a self-rating depression scale. We used voxel-based morphometry (VBM) to examine the GMV differences between the MM and healthy control groups. The identified brain areas were selected as seeds to assess functional changes in the MM group. Correlation analysis between the altered VBM/rsFC and clinical outcomes was performed.

Results

Compared with healthy controls, patients with MM showed decreased GMV in the right anterior cingulum cortex (ACC) and increased GMV in the right superior parietal cortex. Pearson’s correlation analysis illustrated that only GMV in the right ACC was associated with visual analogue scale pain scores in the MM group. RsFC with the ACC as the seed showed that patients with MM exhibited increased FC between the ACC and the left inferior temporal gyrus, bilateral angular gyrus, and right precuneus. Correlation analysis showed that the change in FC between the right ACC and the right precuneus was positively correlated with headache frequency, and the change in FC between the right ACC and the right angular gyrus was positively correlated with the depression score.

Conclusion

Our results suggested that the ACC may be an important biomarker in MM, and its structural and functional impairments are significantly associated with the severity of pain and pain-related impairment of emotion in patients with MM. These findings demonstrated that headache-associated structural and functional abnormalities in the ACC may can provide integrative evidence on the physiological mechanisms of MM.

Gene-environment interactions explain a substantial portion of variability of common neuropsychiatric disorders

In complex diseases, the phenotypic variability can be explained by genetic variation (G), environmental stimuli (E), and interaction of genetic and environmental factors (G-by-E effects), among which the contribution G-by-E remains largely unknown. In this study, we focus on ten major neuropsychiatric disorders using data for 138,383 United States families with 404,475 unique individuals. We show that, while gene-environment interactions account for only a small portion of the total phenotypic variance for a subset of disorders (depression, adjustment disorder, substance abuse), they explain a rather large portion of the phenotypic variation of the remaining disorders: over 20% for migraine and close to or over 30% for anxiety/phobic disorder, attention-deficit/hyperactivity disorder, recurrent headaches, sleep disorders, and post-traumatic stress disorder. In this study, we have incorporated—in the same analysis—clinical data, family pedigrees, the spatial distribution of individuals, their socioeconomic and demographic confounders, and a collection of environmental measurements.

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G-by-E interactions contribute to the etiology of neuropsychiatric disorders

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Environmental quality is associated with the risk of neuropsychiatric disorders

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Geographic locations explain a part of variability of neuropsychiatric disorders

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Identifying specific G-by-E interactions might be the future of personalized medicine

Stimulation of CGRP-expressing neurons in the medial cerebellar nucleus induces light and touch sensitivity in mice

Calcitonin gene-related peptide (CGRP) is considered a major player in migraine pathophysiology. However, the location and mechanisms of CGRP actions in migraine are not clearly elucidated. One important question yet to be answered is: Does central CGRP signaling play a role in migraine? One candidate site is the cerebellum, which serves as a sensory and motor integration center and is activated in migraine patients. The cerebellum has the most CGRP binding sites in the central nervous system and a deep cerebellar nucleus, the medial nucleus (MN), expresses CGRP (MN^CGRP). A previous study demonstrated that CGRP delivery into the cerebellum induced migraine-like behaviors. We hypothesized that stimulation of MN^CGRP neurons might induce migraine-like behaviors. To test the hypothesis, we used an optogenetic strategy using Calca^Cre/+ mice to drive Cre-dependent expression of channelrhodopsin-2 selectively in CGRP neurons in the cerebellar MN. A battery of behavioral tests was done to assess preclinical behaviors that are surrogates of migraine symptoms, including light aversion, cutaneous allodynia, and spontaneous pain when MN^CGRP neurons were optically stimulated. Motor functions were also assessed. Optical stimulation of MN^CGRP neurons decreased the time spent in the light, which was coupled to increased time spent resting in the dark, but not the light. These changes were only significant in female mice. Plantar tactile sensitivity was increased in the ipsilateral paws of both sexes, but contralateral paw data were less clear. There was no significant increase in anxiety-like behavior, spontaneous pain (squint), or changes in gait. These discoveries reveal that MN^CGRP neurons may contribute to migraine-like sensory hypersensitivity to light and touch.

CGRP Administration Into the Cerebellum Evokes Light Aversion, Tactile Hypersensitivity, and Nociceptive Squint in Mice

The neuropeptide calcitonin gene-related peptide (CGRP) is a major player in migraine pathophysiology. Previous preclinical studies demonstrated that intracerebroventricular administration of CGRP caused migraine-like behaviors in mice, but the sites of action in the brain remain unidentified. The cerebellum has the most CGRP binding sites in the central nervous system and is increasingly recognized as both a sensory and motor integration center. The objective of this study was to test whether the cerebellum, particularly the medial cerebellar nuclei (MN), might be a site of CGRP action. In this study, CGRP was directly injected into the right MN of C57BL/6J mice via a cannula. A battery of tests was done to assess preclinical behaviors that are surrogates of migraine-like symptoms. CGRP caused light aversion measured as decreased time in the light zone even with dim light. The mice also spent more time resting in the dark zone, but not the light, along with decreased rearing and transitions between zones. These behaviors were similar for both sexes. Moreover, significant responses to CGRP were seen in the open field assay, von Frey test, and automated squint assay, indicating anxiety, tactile hypersensitivity, and spontaneous pain, respectively. Interestingly, CGRP injection caused significant anxiety and spontaneous pain responses only in female mice, and a more robust tactile hypersensitivity in female mice. No detectable effect of CGRP on gait was observed in either sex. These results suggest that CGRP injection in the MN causes light aversion accompanied by increased anxiety, tactile hypersensitivity, and spontaneous pain. A caveat is that we cannot exclude contributions from other cerebellar regions in addition to the MN due to diffusion of the injected peptide. These results reveal the cerebellum as a new site of CGRP actions that may contribute to migraine-like hypersensitivity.

Sex Differences of Periaqueductal Grey Matter Functional Connectivity in Migraine

The existence of “sex phenotype” in migraine is a long-standing scientific question. Fluctuations of female sex hormones contribute to migraine attacks, and women also have enhanced brain activity during emotional processing and their functional brain networks seem to be more vulnerable to migraine-induced disruption compared to men. Periaqueductal grey matter (PAG) is a core region of pain processing and modulation networks with possible sex-related implications in migraine. In our study, sex differences of PAG functional resting-state connectivity were investigated in the interictal state in 32 episodic migraines without aura patients (16 women and 16 men). A significant main effect of sex was detected in PAG connectivity with postcentral, precentral, and inferior parietal gyri, and further differences were found between right PAG and visual areas (superior occipital gyrus, calcarine, and cuneus), supplementary motor area, and mid-cingulum connectivity. In all cases, PAG functional connectivity was stronger in female migraineurs compared to males. However, higher average pain intensity of migraine attacks correlated with stronger connectivity of PAG and middle temporal, superior occipital, and parietal gyri in male migraineurs compared to females. Migraine-related disability is also associated with PAG connectivity but without sex differences. Our results indicate that sex differences in PAG connectivity with brain regions involved in sensory and emotional aspects of pain might contribute to the “sex-phenotype” in migraine. The stronger functional connectivity between PAG and pain processing areas may be a sign of increased excitability of pain pathways even in resting-state in females compared to male migraineurs, which could contribute to female vulnerability for migraine. However, pain intensity experienced by male migraineurs correlated with increased connectivity between PAG and regions involved in the subjective experience of pain and pain-related unpleasantness. The demonstrated sex differences of PAG functional connectivity may support the notion that the female and male brain is differently affected by migraine.

Migraine: A Review on Its History, Global Epidemiology, Risk Factors, and Comorbidities

Migraine affects more than one billion individuals each year across the world, and is one of the most common neurologic disorders, with a high prevalence and morbidity, especially among young adults and females. Migraine is associated with a wide range of comorbidities, which range from stress and sleep disturbances to suicide. The complex and largely unclear mechanisms of migraine development have resulted in the proposal of various social and biological risk factors, such as hormonal imbalances, genetic and epigenetic influences, as well as cardiovascular, neurological, and autoimmune diseases. This review presents a comprehensive review of the most up-to-date literature on the epidemiology, and risk factors, as well as highlighting the gaps in our knowledge.

Global, regional, and national burden of migraine in 204 countries and territories, 1990 to 2019

ABSTRACT

Data from the Global Burden of Disease Study 2019 were used to report the burden of migraine in 204 countries and territories during the period 1990 to 2019, through a systematic analysis of point prevalence, annual incidence, and years lived with disability (YLD). In 2019, the global age-standardised point prevalence and annual incidence rate of migraine were 14,107.3 (95% Uncertainty Interval [UI] 12,270.3-16,239) and 1142.5 (95% UI 995.9-1289.4) per 100,000, an increase of 1.7% (95% UI 0.7%-2.8%) and 2.1% (95% UI 1.1%-2.8%) since 1990, respectively. Moreover, the global age-standardised YLD rate in 2019 was 525.5 (95% UI 78.8-1194), an increase of 1.5% (95% UI -4.4% to 3.3%) since 1990. The global point prevalence of migraine in 2019 was higher in females and increased by age up to the 40 to 44 age group, then decreased with increased age. Belgium (22,400.6 [95% UI: 19,305.2-26,215.8]), Italy (20,337.7 [95% UI: 17,724.7-23,405.8]), and Germany (19,436.4 [95% UI: 16,806.2-22,810.3]) had the 3 highest age-standardised point prevalence rates for migraine in 2019. In conclusion, there were large intercountry differences in the burden of migraine, and this burden increased significantly across the measurement period. These findings suggest that migraine care needs to be included within the health system to increase population awareness regarding the probable risk factors and treatment strategies especially among young adults and middle-aged women, as well as to increase the data on migraines.

The effects of neonatal maternal deprivation and chronic unpredictable stresses on migraine-like behaviors in adult rats

BACKGROUND

Stress is known to cause migraine. This study investigates the effects of neonatal maternal deprivation (MD) and chronic unpredictable stress (CUS) on migraine in rats.

METHODS

Seventy rats were randomly divided into ten groups (five groups of each sex, and seven rats/group). The groups included: untreated intact, nitroglycerin (NTG) only, NTG + MD, NTG + CUS (10 weeks after birth), and NTG + MD + CUS. For the induction of MD, pups were separated from their mothers from postnatal day 2 to day 14. The CUS was conducted by daily exposure to different stressors for 2 weeks. For the induction of migraine after stress, NTG (5 mg/kg/IP) was administered every second day for 9 days. Afterward, NTG-related symptoms, including climbing behavior, facial rubbing, body grooming, freezing behavior, and head-scratching, were recorded for 90 min. Statistical differences between the groups were analyzed by one-way and two-way ANOVA followed by the Newman-Keuls test.

RESULTS

Migraine symptoms, including increased head-scratching, facial rubbing, and decreased climbing behavior, were more significant in females than in males. Head scratching and facial rubbing increased in stressed females, but not in males as compared to NTG-treated rats. Body grooming was significantly decreased in MD males compared to the NTG group. The effects of NTG in MD + CUS on the rats did not differ from those in the MD or CUS groups.

CONCLUSIONS

MD and CUS had a sex-related aggravating effect on the development of migraine, while the combination of MD and CUS had no additive migraine-aggravating effect.

Migraine prevalence, clinical characteristics, and health care-seeking practice in a sample of medical students in Egypt

Introduction

Migraine is a common disabling primary headache disorder with significant personal and socio-economic impacts. Medical students usually have multiple triggers for migraine, particularly stress and irregular sleep.

Objective

To assess the prevalence, characteristics, and degree of disability of migraine in a sample of Egyptian medical students and to study their health care-seeking practice when having migraine

Patients and methods

A descriptive cross-sectional, questionnaire-based study included 631 undergraduate medical students enrolled in the Faculty of Medicine. Participants’ sociodemographic data, migraine prevalence, characteristic, migraine disability, and health care-seeking practice were evaluated. By using the MIDAS test in the questionnaire, we assessed the impact of migraine headache on the daily activities of the students. The severity of headache was assessed using the visual analog scale (VAS) scores.

Results

Prevalence of migraine in medical students was found to be 17.9% causing moderate disability. Migraine was significantly more prevalent and caused more disability among female students compared to males (p value 0.001 and 0.001). Only 35.4% of the migraineurs had already seen doctors for their migraine, and self-prescription of medications for migraine was practiced by 58.4%. Statistically significant positive correlation was found between migraine frequency, migraine severity, and low academic performance (p value 0.001 and 0.003 respectively).

Conclusion

Migraine is highly prevalent among medical students with predominant female prevalence and has a negative impact on their academic performance and other activities.

Identifying super-feminine, super-masculine and sex-defining connections in the human braingraph

For more than a decade now, we can discover and study thousands of cerebral connections with the application of diffusion magnetic resonance imaging (dMRI) techniques and the accompanying algorithmic workflow. While numerous connectomical results were published enlightening the relation between the braingraph and certain biological, medical, and psychological properties, it is still a great challenge to identify a small number of brain connections closely related to those conditions. In the present contribution, by applying the 1200 Subjects Release of the Human Connectome Project (HCP) and Support Vector Machines, we identify just 102 connections out of the total number of 1950 connections in the 83-vertex graphs of 1064 subjects, which-by a simple linear test-precisely, without any error determine the sex of the subject. Next, we re-scaled the weights of the edges-corresponding to the discovered fibers-to be between 0 and 1, and, very surprisingly, we were able to identify two graph edges out of these 102, such that, if their weights are both 1, then the connectome always belongs to a female subject, independently of the other edges. Similarly, we have identified 3 edges from these 102, whose weights, if two of them are 1 and one is 0, imply that the graph belongs to a male subject-again, independently of the other edges. We call the former 2 edges superfeminine and the first two of the 3 edges supermasculine edges of the human connectome. Even more interestingly, the edge, connecting the right Pars Triangularis and the right Superior Parietal areas, is one of the 2 superfeminine edges, and it is also the third edge, accompanying the two supermasculine connections if its weight is 0; therefore, it is also a "switching" edge. Identifying such edge-sets of distinction is the unprecedented result of this work.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s11571-021-09687-w.

Effectiveness and Safety of CGRP-mAbs in Menstrual-Related Migraine: A Real-World Experience

INTRODUCTION

Migraine shows a significantly higher prevalence in women, especially during reproductive age when menstrual-related hormonal fluctuations represent the most common migraine trigger. Indeed, over 50% of patients report a higher occurrence of migraine attacks during the perimenstrual window. Menstrual migraine attacks are consistently referred to as more disabling, less responsive to symptomatic treatments, longer in duration, and more prone to relapse than non-menstrual migraine attacks. Evidence strongly suggests that estrogen fluctuations are involved in migraine attacks worsening during the perimenstrual window through several mechanisms directly or indirectly involving the CGRP pathway. We aimed to evaluate whether mAbs blocking CGRP-ligand or receptor (CGRP-mAbs) could represent an effective and safe preventive treatment for menstrual migraine attacks in patients with menstrual-related migraine (MRM) with previous treatment failures.

METHODS

Forty patients with MRM with at least three previous treatment failures received monthly CGRP-mAbs. At the baseline and after six CGRP-mAbs administrations, patients underwent to extensive interviews to assess frequency, duration, intensity, and responsiveness to painkiller intake of migraine attacks occurring during the perimenstrual window.

RESULTS

After six administrations of CGRP-mAbs we observed a reduction of median menstrual migraine frequency (from 5 to 2 days per month), pain intensity (from 8/10 to 6/10), and attacks duration (from 24 to 8 h) (p < 0.001). Nevertheless, a significant increase in the percentage of responding to migraine painkillers was observed from 42.5% at baseline to 95% at T1 (p < 0.001).

CONCLUSIONS

CGRP-mAbs could represent a safe and effective preventive therapeutic strategy able to reduce the disabling burden of menstrual migraine attack frequency, duration, intensity, and significantly improve the response to painkillers. These findings could be related to and further indirectly prove the greater influence of CGRP-mediated mechanisms in the pathophysiology of menstrual migraine attacks.

Hormonal therapies in migraine management: current perspectives on patient selection and risk management

INTRODUCTION

The link between sex hormones and migraines has long been investigated but the mechanisms underlying this altered interaction are not yet fully understood. Herein, we retrace the knowledge on this association in relationship with risk of stroke.

AREAS COVERED

Estrogens fluctuations could trigger migraine attacks and exogenous estrogens intake could be a risk factor for venous thromboembolism (VTE) and stroke. At the same time, ischemic heart diseases and stroke share a common substrate with migraine and other mood disorders, depression, and anxiety.

EXPERT OPINION

The use of hormonal therapies in the context of contraception or replacement therapy must be closely evaluated in a careful risk assessment. We highlight the complex interaction of hormone/neuroinflammation pathways underlying the pathophysiology of migraine glimpsing in mood disorders a possible common denominator of link between hormonal and neuronal systems.

Alterations in Effective Connectivity of the Hippocampus in Migraine without Aura

Purpose

Neuroimaging studies on migraine have revealed structural and functional alterations in the hippocampus, a region involved in pain processing and stress response. This study was designed to investigate whether effective connectivity of this region is disrupted in migraine and relates to chronicity of this disease.

Patients and Methods

In 39 episodic migraine (EM) patients, 17 chronic migraine (CM) patients, and 35 healthy controls, we investigated differences in the directional influences between the hippocampus and the rest of the brain by combining resting-state functional magnetic resonance imaging and Granger causality analysis (GCA), with bilateral hippocampus as seed regions. The associations between directional influences and the clinical variables were also examined.

Results

Comparing each patient group to the control group, we found increased and decreased negative influence on the hippocampus exerted by the bilateral visual areas and right dorsolateral prefrontal cortex (dlPFC), respectively. The hippocampus showed increased positive influence on the right posterior insula and medial prefrontal cortex (mPFC), as well as increased negative influence on the left cerebellum in CM patients relative to EM patients and healthy controls. Furthermore, across all patients, the migraine frequency exhibited a positive and negative association with causal influence from the hippocampus to mPFC and left cerebellum, respectively.

Conclusion

Migraine patients have abnormal effective connectivity between the hippocampus and multiple brain regions involved in the sensory and cognitive processing of pain. Disrupted directional influences to the hippocampus exerted by dlPFC and bilateral visual areas were common features of EM and CM patients. Directional influences from the hippocampus to mPFC and left cerebellum may be useful imaging biomarkers for assessing migraine frequency.

Regulatory Effects of Acupuncture on Emotional Disorders in Patients With Menstrual Migraine Without Aura: A Resting-State fMRI Study

Background: Menstrual migraine without aura (MMoA) refers to a specific type of migraine that is associated with the female ovarian cycle. It is particularly serious and has brought huge life pressure and mental burden to female patients. Acupuncture has been commonly used to prevent migraines and relieve concomitant emotional disorders; however, the physiological mechanism underlying this intervention remains unclear. This study aimed to use resting-state functional magnetic resonance imaging (rsfMRI) to investigate whether acupuncture can modulate brain function and if the potential influence on brain activity correlates with improving emotional symptoms in MMoA patients. Methods: Overall, 44 patients were randomly divided into a true acupuncture (TA) group and the sham acupuncture (SA) group. Patients underwent rsfMRI before and after 3-month treatment, the amplitude of low-frequency fuctuations (ALFF) and regional homogeneity (ReHo) in rsfMRI were calculated. Zung self-rating anxiety scale (SAS), Zung self-rating depression scale (SDS), frequency of migraine attacks, visual analog scale, and intensity of the migraine were used for evaluate the clinical effect. The clinical changes of variables were also used to further assess the correlation with brain activity in MMoA patients. Results: After acupuncture treatment, the emotional symptoms of both groups of patients improved, and the clinical symptoms of migraine were alleviated. The major finding of our study was that patients with MMoA showed lower ALFF value in the left anterior cingulate and the value was positively correlated with the decreases in the SAS and SDS scores. In the SA group, common brain regions responded both in ALFF and regional homogeneity values mainly in the insula, and no significant correlations were observed between brain regions and clinical variables. Conclusions: These results indicated that both two acupuncture treatments were helpful in treating migraine and could improve emotion symptoms. TA had a relatively better effect in reducing the frequency of migraine attack than SA. The two therapies have different modulation effects as TA regulates emotional disorders by modulating the frontal-limbic regions, and SA may modulate pain perception through the placebo effect on insula and by indirectly regulating emotional disorders. These findings provided evidence that acupuncture is a complementary and alternative therapy to relieve clinical symptoms in female patients with migraines and could help enhance clinical diagnosis and treatment. Clinical Trial Registration: [http://www.chictr.org.cn/index.aspx], identifier [ChiCTR-IOR-15006648. Registered 23 June 2015].

New and sex-specific migraine susceptibility loci identified from a multiethnic genome-wide meta-analysis

Migraine is a common disabling primary headache disorder that is ranked as the most common neurological cause of disability worldwide. Women present with migraine much more frequently than men, but the reasons for this difference are unknown. Migraine heritability is estimated to up to 57%, yet much of the genetic risk remains unaccounted for, especially in non-European ancestry populations. To elucidate the etiology of this common disorder, we conduct a multiethnic genome-wide association meta-analysis of migraine, combining results from the GERA and UK Biobank cohorts, followed by a European-ancestry meta-analysis using public summary statistics. We report 79 loci associated with migraine, of which 45 were novel. Sex-stratified analyses identify three additional novel loci (CPS1, PBRM1, and SLC25A21) specific to women. This large multiethnic migraine study provides important information that may substantially improve our understanding of the etiology of migraine susceptibility.

Early alterations of cortical thickness and gyrification in migraine without aura: a retrospective MRI study in pediatric patients

Background

Migraine is the most common neurological disease, with high social-economical burden. Although there is growing evidence of brain structural and functional abnormalities in patients with migraine, few studies have been conducted on children and no studies investigating cortical gyrification have been conducted on pediatric patients affected by migraine without aura.

Methods

Seventy-two pediatric patients affected by migraine without aura and eighty-two controls aged between 6 and 18 were retrospectively recruited with the following inclusion criteria: MRI exam showing no morphological or signal abnormalities, no systemic comorbidities, no abnormal neurological examination. Cortical thickness (CT) and local gyrification index (LGI) were obtained through a dedicated algorithm, consisting of a combination of voxel-based and surface-based morphometric techniques. The statistical analysis was performed separately on CT and LGI between: patients and controls; subgroups of controls and subgroups of patients.

Results

Patients showed a decreased LGI in the left superior parietal lobule and in the supramarginal gyrus, compared to controls. Female patients presented a decreased LGI in the right superior, middle and transverse temporal gyri, right postcentral gyrus and supramarginal gyrus compared to male patients. Compared to migraine patients younger than 12 years, the ≥ 12-year-old subjects showed a decreased CT in the superior and middle frontal gyri, pre- and post-central cortex, paracentral lobule, superior and transverse temporal gyri, supramarginal gyrus and posterior insula. Migraine patients experiencing nausea and/or vomiting during headache attacks presented an increased CT in the pars opercularis of the left inferior frontal gyrus.

Conclusions

Differences in CT and LGI in patients affected by migraine without aura may suggest the presence of congenital and acquired abnormalities in migraine and that migraine might represent a vast spectrum of different entities. In particular, ≥ 12-year-old pediatric patients showed a decreased CT in areas related to the executive function and nociceptive networks compared to younger patients, while female patients compared to males showed a decreased CT of the auditory cortex compared to males. Therefore, early and tailored therapies are paramount to obtain migraine control, prevent cerebral reduction of cortical thickness and preserve executive function and nociception networks to ensure a high quality of life.

Gender-related differences in migraine

Migraine is considered mostly a woman’s complaint, even if it affects also men. Epidemiological data show a higher incidence of the disease in women, starting from puberty throughout life. The sex-related differences of migraine hold clinical relevance too. The frequency, duration, and disability of attacks tend to be higher in women. Because of this, probably, they also consult specialists more frequently and take more prescription drugs than men. Different mechanisms have been evaluated to explain these differences. Hormonal milieu and its modulation of neuronal and vascular reactivity is probably one of the most important aspects. Estrogens and progesterone regulate a host of biological functions through two mechanisms: nongenomic and genomic. They influence several neuromediators and neurotransmitters, and they may cause functional and structural differences in several brain regions, involved in migraine pathogenesis. In addition to their central action, sex hormones exert rapid modulation of vascular tone. The resulting specific sex phenotype should be considered during clinical management and experimental studies.

Gender differences in health-related quality of life measured by the Sarcoidosis Health Questionnaire

Sarcoidosis is granulomatous disease, which complex etiology is yet to be fully discovered. In the majority of cases its course is self-limiting. However it can have different clinical manifestations and can be debilitating condition with great impact on health-related quality of life (HRQL). The aim of our study was to assess if there are any differences in HRQL dependent to gender. We examined a group of 33 males and 42 females (with no differences in mean age, disease activity, TLCO, FEV₁, FVC, FEV₁/FVC) with a use of Sarcoidosis Health Questionnaire. We revealed lower total and daily functioning score in female group. Further analyses stratified by sex and activity of the disease presented many significant differences between the groups, revealing important issues for the discussion about gender specific differences in the HRQL of patients with sarcoidosis. In spite of clinical presentation may be similar, expectations and main concerns of sarcoidosis patient can vary between females and males. Therefore, it appears that in terms of education and symptomatic treatment accents should be put differently depending on the gender of the patient. Our results may also point to a need for more gender-oriented patient-physician communication which could enable better understanding, potentially improve adherence to therapy and decrease the risk of possible complications.

Sexism-Related Stigma Affects Pain Perception

People with stigmatized characteristics tend to be devalued by others in a given society. The negative experiences related to stigma cause individuals to struggle as they would if they were in physical pain and bring various negative outcomes in the way that physical pain does. However, it is unclear whether stigma related to one's identity would affect their perception of physical pain. To address this issue, using sexism-related paradigms, we found that females had reduced pain threshold/tolerance in the Cold Pressor Test (Experiment 1) and an increased rating for nociceptive laser stimuli with fixed intensity (Experiment 2). Additionally, we observed that there was a larger laser-evoked N1, an early laser-evoked P2, and a larger magnitude of low-frequency component in laser-evoked potentials (LEPs) in the stigma condition than in the control condition (Experiment 3). Our study provides behavioral and electrophysiological evidence that sexism-related stigma affects the pain perception of females.

Enhanced amygdala-frontal operculum functional connectivity during rest in women with chronic neck pain: Associations with impaired conditioned pain modulation

BACKGROUND

Chronic neck pain is a leading cause of disability worldwide, affecting the lives of millions of people. Research investigating functional brain alterations in relation to somatosensory function is necessary to better understand mechanisms underlying pain development and maintenance in individuals with chronic neck pain, yet remains scarce. This case-control study aimed to examine resting-state functional connectivity alterations and associations with pain outcomes, self-reported central sensitization-related symptoms and quantitative sensory testing (QST) measures in patients with chronic non-traumatic (idiopathic/CINP) neck pain and chronic traumatic (whiplash associated/CWAD) neck pain compared to pain-free controls.

METHODS

Resting-state functional magnetic resonance images were acquired in 107 female participants (38 CINP, 37 CWAD, 32 healthy controls). After data pre-processing, seed-to-seed analyses were conducted focusing on resting-state functional connectivity involving pre-defined regions of interest that have previously been observed to be structurally or functionally altered and/or associated with pain-related measures in this patient population.

RESULTS

Findings demonstrate enhanced left amygdala functional coupling during rest with the left frontal operculum in women with CINP and CWAD compared to controls. This increased resting-state functional connectivity was associated with more self-reported symptoms related to central sensitization and decreased efficacy of conditioned pain modulation. Furthermore, enhanced connectivity between the left amygdala and left frontal orbital cortex, and between the left pallidum and the left frontal operculum was observed only in patients with CWAD compared to healthy controls. In patients, additional associations between local hyperalgesia and enhanced connectivity between the left superior parietal cortex and the left and right precentral gyrus were found.

CONCLUSIONS

In line with our hypotheses, patients with CWAD showed the most pronounced alterations in resting-state functional connectivity, encompassing subcortical limbic (amygdala) and basal ganglia (pallidum), and ventral frontal regions (frontal operculum, orbitofrontal cortex) when compared to CINP and controls. Findings are generally in line with the idea of a continuum, in absence of significant group differences across CINP and CWAD. Enhanced amygdala-frontal operculum functional connectivity was the most robust and only connectivity pair in the cluster that was associated with QST (i.e., dynamic QST; endogenous pain inhibition), and that was observed in both patient groups. In addition, independent of group differences, enhanced resting-state functional connectivity between superior parietal cortex (involved in attention) and primary motor cortex was associated with static QST (i.e., greater local hyperalgesia). Taken together, our findings show a key role for enhanced amygdala-ventral frontal circuitry in chronic neck pain, and its association with diminished endogenous pain inhibition further emphasizes the link between cognitive-affective and sensory modulations of pain in women with chronic non-traumatic and traumatic neck pain.

Current Understanding of the Involvement of the Insular Cortex in Neuropathic Pain: A Narrative Review

Neuropathic pain is difficult to cure and is often accompanied by emotional and psychological changes. Exploring the mechanisms underlying neuropathic pain will help to identify a better treatment for this condition. The insular cortex is an important information integration center. Numerous imaging studies have documented increased activity of the insular cortex in the presence of neuropathic pain; however, the specific role of this region remains controversial. Early studies suggested that the insular lobe is mainly involved in the processing of the emotional motivation dimension of pain. However, increasing evidence suggests that the role of the insular cortex is more complex and may even be related to the neural plasticity, cognitive evaluation, and psychosocial aspects of neuropathic pain. These effects contribute not only to the development of neuropathic pain, but also to its comorbidity with neuropsychiatric diseases. In this review, we summarize the changes that occur in the insular cortex in the presence of neuropathic pain and analgesia, as well as the molecular mechanisms that may underlie these conditions. We also discuss potential sex-based differences in these processes. Further exploration of the involvement of the insular lobe will contribute to the development of new pharmacotherapy and psychotherapy treatments for neuropathic pain.

Altered functional connectivity of the insula in a rat model of recurrent headache

Migraine is a pain disorder accompanied by various symptoms. The insula, a “cortical hub,” is involved in many functions. Few studies have focused on the insula in migraine. We explored the resting-state functional connectivity between the insula and other brain areas in rats subjected to repeated meningeal nociception which was commonly used as animal model of migraine. Inflammatory soup was infused through supradural catheters in conscious rats. The rats were subdivided based on the frequency of the inflammatory soup infusions. Magnetic resonance imaging data were acquired on rats 21 days after inflammatory soup infusion and functional connectivity seeded on the insula was analyzed. In the low-frequency inflammatory soup group, magnetic resonance imaging was performed again 1 h after the glyceryl trinitrate injection following baseline scanning. The cerebellum showed increased functional connectivity with the insula in the inflammatory soup groups. The insula showed increased functional connectivity with the medulla and thalamus in the ictal period in the low-frequency inflammatory soup rats. In the high-frequency inflammatory soup group, several areas showed increased functional connectivity with the insula, including the pons, midbrain, thalamus, temporal association cortex, and retrosplenial, visual, and sensory cortices. Our findings support the hypothesis that the headache phase of migraine depends on the activation and sensitization of the trigeminovascular system, and that the chronification of migraine may be related to higher brain centers and limbic cortices. The insula may be a new target for treatment of migraine.