Involvement of the cerebellum in migraine

Effects of acute sleep deprivation on the brain function of individuals with migraine: a resting-state functional magnetic resonance imaging study

BACKGROUND

Sleep deprivation can trigger acute headache attacks in individuals with migraine; however, the underlying mechanism remains poorly understood. The aim of this study was to investigate the effects of acute sleep deprivation (ASD) on brain function in individuals with migraine without aura (MWoA) via functional magnetic resonance imaging (fMRI).

METHODS

Twenty three MWoA individuals and 23 healthy controls (HCs) were fairly included in this study. All participants underwent two MRI scans: one at baseline (prior to sleep deprivation) and another following 24 h of ASD. Images were obtained with blood-oxygen-level-dependent and T1-weighted sequences on a Siemens 7.0 T MRI scanner. We conducted analyses of changes in the low-frequency fluctuations (ALFF) values and functional connectivity (FC) between brain networks and within network before and after ASD in both MWoA group and HC group. Additionally, we investigated the relationship between the changes in ALFF before and after ASD and the clinical features (VAS and monthly headache days).

RESULTS

In the HC group, ASD led to a significant increase in ALFF values in the left parahippocampal gyrus compared to baseline (p-FDR = 0.01). In the MWoA group, ALFF values were significantly greater in 64 brain regions after ASD than at baseline. The most significant change in ALFF before and after ASD in the MWoA group was detected in the right medial pulvinar of the thalamus (p-FDR = 0.017), which showed a significant negative correlation with monthly headache days. Moreover, seed-based connectivity (SBC) analysis using the right medial pulvinar of the thalamus as the seed point revealed significantly increased connectivity with the cerebellar vermis (p-FWE = 0.035) after ASD in individuals with MWoA, whereas connectivity with the right postcentral gyrus was significantly decreased (p-FWE = 0.048). Furthermore, we performed analyses of between-network connectivity (BNC) and within-network connectivity across 17 brain networks, utilizing the Yeo-17 atlas. Both MWoA individuals and HCs showed no significant changes in BNC after ASD compared to baseline. However, our analysis in within-network revealed that MWoA individuals exhibited a reduced within-network FC in dorsal attention network (DAN) after ASD compared to baseline (p-FDR = 0.031), whereas HCs showed no significant differences in within-network FC across all networks before and after ASD.

CONCLUSIONS

In comparison to HCs, MWoA individuals exhibited significant alterations in brain function after ASD, particularly within the thalamus, and MWoA individuals exhibited a reduced within-network FC in DAN after ASD compared to baseline. Brain regions and networks in MWoA individuals were more susceptible to the effects of ASD.

Language errors in pain medicine: An umbrella review

Errors in language are common in pain medicine, but the extent of such errors has not been systematically measured. This pre-registered umbrella review explored Embase, PubMed, Medline and CINAHL and seeks to quantify the prevalence of errors in language in review articles since the last IASP definition revision. To be eligible, studies must have met the following criteria: 1) Primary aim was stated as to provide neurophysiological explanations of nociception and/or pain in humans in context of a pathology/condition; 2) Any type of review article; 3) Written in English; 4) Published in a peer-reviewed journal. Studies were excluded if they met any of the following criteria: 5) Published prior to the last revision of the IASP definition; 6) Published after May 2023; 7) Published in a predatory journal. Out of 5470 articles screened, 48 review articles met the inclusion criteria. All articles contained at least one error in language, there were no differences in the proportions of errors in language in review articles between years of publication, and various predictors were mostly not associated with a higher or lower number of errors in language counts in articles. Our findings reveal the need for heightened awareness among researchers, clinicians, journals and editorial boards regarding the prevalence and impact of these errors. Given our findings and their limitations, further research should focus on examining the contextual influence of misnomer usage and replication of these results. PERSPECTIVE: This umbrella review explored the main biomedical databases to see how many review articles contained language errors. Our findings underscore the imperative for prompt action in regulating pain medicine terminology. PRE-REGISTRATION: This umbrella review was pre-registered on OSF registries (https://doi.org/10.17605/osf.io/kau8m). ONLINE MATERIAL: https://osf.io/kdweg/.

Involvement of the cerebellum in structural connectivity enhancement in episodic migraine

BACKGROUND

The pathophysiology of migraine remains poorly understood, yet a growing number of studies have shown structural connectivity disruptions across large-scale brain networks. Although both structural and functional changes have been found in the cerebellum of migraine patients, the cerebellum has barely been assessed in previous structural connectivity studies of migraine. Our objective is to investigate the structural connectivity of the entire brain, including the cerebellum, in individuals diagnosed with episodic migraine without aura during the interictal phase, compared with healthy controls.

METHODS

To that end, 14 migraine patients and 15 healthy controls were recruited (all female), and diffusion-weighted and T1-weighted MRI data were acquired. The structural connectome was estimated for each participant based on two different whole-brain parcellations, including cortical and subcortical regions as well as the cerebellum. The structural connectivity patterns, as well as global and local graph theory metrics, were compared between patients and controls, for each of the two parcellations, using network-based statistics and a generalized linear model (GLM), respectively. We also compared the number of connectome streamlines within specific white matter tracts using a GLM.

RESULTS

We found increased structural connectivity in migraine patients relative to healthy controls with a distinct involvement of cerebellar regions, using both parcellations. Specifically, the node degree of the posterior lobe of the cerebellum was greater in patients than in controls and patients presented a higher number of streamlines within the anterior limb of the internal capsule. Moreover, the connectomes of patients exhibited greater global efficiency and shorter characteristic path length, which correlated with the age onset of migraine.

CONCLUSIONS

A distinctive pattern of heightened structural connectivity and enhanced global efficiency in migraine patients compared to controls was identified, which distinctively involves the cerebellum. These findings provide evidence for increased integration within structural brain networks in migraine and underscore the significance of the cerebellum in migraine pathophysiology.

Differences in Static and Dynamic Resting-State Functional Connectivity between Migraineurs with and without Photophobia, without Phonophobia or Osmophobia

BACKGROUND

We have previously shown that static and dynamic resting-state functional connectivity differ between migraineurs with and without photophobia, phonophobia, or osmophobia. Furthermore, some patients with photophobia also experience phonophobia or osmophobia. To investigate the functional connectivity specific to migraineurs with photophobia, we examined the differences in static and dynamic resting-state functional connectivity between patients with and without photophobia, with no phonophobia or osmophobia.

METHODS

Fifteen migraineurs with photophobia but without phonophobia or osmophobia, as well as 15 sex- and age-matched migraineurs without photophobia, phonophobia, or osmophobia, underwent 3-T functional magnetic resonance imaging during the interictal phase. Static and dynamic resting-state functional connectivity were compared using region-of-interest analyses of 91 cortical, 15 subcortical, and 26 cerebellar areas.

RESULTS

Static resting-state functional connectivity analysis revealed ten significant connectivity pairs in patients with photophobia, while dynamic resting-state functional connectivity analysis revealed six significant connectivity pairs in patients with photophobia. Migraineurs with photophobia had significantly lower connectivity between the cerebellar hemisphere and the temporal region than those without photophobia in both static and dynamic studies.

CONCLUSIONS

Our results show that lower resting-state functional connectivity between the cerebellar hemisphere and the temporal region is specific to migraineurs with photophobia.

Brain structural and functional abnormalities in patients with tension-type headache: A systematic review of magnetic resonance imaging studies

Tension-type headache (TTH) stands as the most prevalent form of headache, yet an adequate understanding of its underlying mechanisms remains elusive. This article endeavors to comprehensively review structural and functional magnetic resonance imaging (MRI) studies investigating TTH patients, to gain valuable insights into the pathophysiology of TTH, and to explore new avenues for enhanced treatment strategies. We conducted a systematic search to identify relevant articles examining brain MRI disparities between TTH individuals and headache-free controls (HFC). Fourteen studies, encompassing 312 diagnosed TTH patients, were selected for inclusion. Among these, eight studies utilized conventional MRI, one employed diffusion tensor imaging, and five implemented various functional MRI modalities. Consistent findings across these studies revealed a notable increase in white matter hyperintensity (WMH) in TTH patients. Furthermore, the potential involvement of the specific brain areas recognized to be involved in different dimensions of pain perception including cortical regions (anterior and posterior cingulate cortex, prefrontal cortex, anterior and posterior insular cortex), subcortical regions (thalamus, caudate, putamen, and parahippocampus), cerebellum in TTH pathogenesis was identified. However, no significant association was established between TTH and intracranial abnormalities or total intracranial volume. In conclusion, these findings support the hypotheses regarding the role of central mechanisms in TTH pathophysiology and offer probable brain regions implicated in these mechanisms. Due to the scarce data on the precise role of these regions in the TTH, further preclinical and clinical investigations should be done to advance our knowledge and enhance targeted therapeutic options of TTH.

The effect of erenumab on brain network function in episodic migraine patients: a randomized, placebo-controlled clinical trial (RESET BRAIN)

BACKGROUND

We aimed to explore whether erenumab, a monoclonal antibody targeting the calcitonin gene-related peptide receptor, could exert a central effect on brain network function in migraine, and investigate the persistence of such an effect following treatment discontinuation.

METHODS

This was a randomized, double-blind, placebo-controlled, multicenter trial with a crossover design performed in adult episodic migraine patients with previous treatment failure. Patients were randomized (1:1) to 12 weeks of erenumab 140 mg or placebo, followed by a 12-week crossover. Resting state (RS) functional connectivity (FC) changes of brain networks involved in migraine were investigated using a seed-based correlation approach.

RESULTS

Sixty-one patients were randomized to treatment. In each treatment sequence, 27 patients completed the visit at week 12. Forty-four enrolled patients, 22 in each treatment sequence, completed the study procedures with no major protocol violations. We observed a carry-over effect of erenumab during the placebo treatment and therefore data analysis was performed as a parallel comparison of erenumab vs placebo of the first 12 weeks of treatment. From baseline to week 12, compared to placebo, patients receiving erenumab showed RS FC changes within the cerebellar, thalamic and periaqueductal gray matter networks, significantly associated with clinical improvement. Compared to non-responders, patients achieving a 50% reduction in migraine days had distinct patterns of thalamic and visual network RS FC. Brain RS FC changes reversed when erenumab was stopped. A lower baseline RS FC of the pontine network identified patients responding to erenumab.

CONCLUSION

Erenumab modulates RS FC of networks involved in migraine pathophysiology. In line with clinical response, erenumab-induced brain RS FC changes tend to reverse when treatment is stopped.

Volumetric Differences in Cerebellum and Brainstem in Patients with Migraine: A UK Biobank Study

Background: The cerebellum and the brainstem are two brain structures involved in pain processing and modulation that have also been associated with migraine pathophysiology. The aim of this study was to investigate possible associations between the morphology of the cerebellum and brainstem and migraine, focusing on gray matter differences in these brain areas. Methods: The analyses were based on data from 712 individuals with migraine and 45,681 healthy controls from the UK Biobank study. Generalized linear models were used to estimate the mean gray matter volumetric differences in the brainstem and the cerebellum. The models were adjusted for important biological covariates such as BMI, age, sex, total brain volume, diastolic blood pressure, alcohol intake frequency, current tobacco smoking, assessment center, material deprivation, ethnic background, and a wide variety of health conditions. Secondary analyses investigated volumetric correlation between cerebellar sub-regions. Results: We found larger gray matter volumes in the cerebellar sub-regions V (mean difference: 72 mm3, 95% CI [13, 132]), crus I (mean difference: 259 mm3, 95% CI [9, 510]), VIIIa (mean difference: 120 mm3, 95% CI [0.9, 238]), and X (mean difference: 14 mm3, 95% CI [1, 27]). Conclusions: Individuals with migraine show larger gray matter volumes in several cerebellar sub-regions than controls. These findings support the hypothesis that the cerebellum plays a role in the pathophysiology of migraine.

Balance alterations are associated with neck pain and neck muscle endurance in migraine

BACKGROUND

Migraine patients may present with both cervical and balance dysfunctions. The neck plays an important role in balance by providing substantial proprioceptive input, which is integrated in the central nervous system and influences the balance control systems. Whether balance and neck dysfunctions are associated in patients with migraine is still to be explored.

OBJECTIVES

This study aimed to assess the association between the sensory organization test of balance with neck pain features, cervical strength, endurance, and range of motion in patients with migraine.

METHODS

Sixty-five patients with migraine underwent the sensory organization test assessed with the Equitest-Neurocom® device. Maximum voluntary isometric contraction, cervical flexion and extension range of motion, and cervical flexor and extensor endurance were assessed. In addition, the features of migraine and neck pain were collected. Patients were dichotomized according to cut-off scores of balance performance and the association between outcomes were explored.

RESULTS

Patients with reduced balance performance presented a higher frequency of migraine (p = 0.035), a higher frequency of aura (p = 0.002), greater neck pain intensity (p = 0.013), and decreased endurance of cervical flexors (p = 0.010) and extensors (p < 0.0001). The total balance score was correlated with age (r = -0.33; p = 0.007), migraine frequency (r = -0.29; p = 0.021), neck pain intensity (r = -0.26; p = 0.038), and endurance of the cervical flexors (r = 0.39; p = 0.001) and extensors (r = 0.36; p = 0.001). Migraine frequency, neck pain intensity, and endurance of the cervical flexors can predict 21% of the sensory organization test variability.

CONCLUSION

Neck pain features and endurance of the cervical muscles are related to reduced balance performance in patients with migraine. These results shed light to a better understanding of balance alterations in migraine patients.