Cortical Alterations in Medication-Overuse Headache

Bridging the gap between preclinical scientists, clinical researchers, and clinicians: From animal research to clinical practice

BACKGROUND

Collaborations amongst researchers and clinicians with complementary areas of expertise enhance knowledge for everyone and can lead to new discoveries. To facilitate these interactions, shared language and a general understanding of how colleagues in different subfields of headache and headache research approach their work are needed.

METHODS

This narrative review focuses on research methods applied in animal studies, human studies including clinical trials, and provides an overview of clinical practice.

RESULTS

For animal studies, we describe concepts needed to evaluate the quality and relevance of preclinical studies. For human research, fundamental concepts of neuroimaging, quantitative sensory testing, genetic and epidemiological research methods, and clinical research methodology that are commonly used in headache research are summarized. In addition, we provide an understanding of what guides headache clinicians, and summarize the practical approach to migraine management in adults and children.

CONCLUSIONS

It is hoped that this review facilitates further dialogue between clinicians and researchers that will help guide future research efforts and implementation of research findings into clinical practice.

Refractory migraine profile in CGRP-monoclonal antibodies scenario

Objective

Refractory migraine (Ref‐M) represents a conundrum that headache experts have to face with. We aim to investigate whether a peculiar profile may characterize patients with Ref‐M according to 2020 European Headache Federation criteria. Furthermore, to substantiate a dysfunctional dopaminergic pathway involvement in these patients, we explored the effectiveness of olanzapine.

Materials & Methods

Eighty‐four patients (fitting previous Ref‐M criteria of the 2014) were treated with erenumab for six months. Differences between clinical and demographic features of responder (Ref‐M according to 2014 criteria) and not‐responder (Ref‐M according to 2020 criteria) patients to CGRP‐mAbs were investigated and their predictive values assessed. In fifteen patients with Ref‐M not responders to CGRP‐mAbs, olanzapine was administered (5 mg/die) for 3 months and frequency and pain intensity of migraine attacks were estimated.

Results

Patients with Ref‐M not responsive to CGRP‐mAbs (29/84) when compared with Ref‐M responsive to CGRP‐mAbs showed higher baseline frequency of migraine attacks, medication overuse and pain catastrophizing scale (PCS) scores. Logistic regression analyses showed that frequency of attacks, medication overuse and PCS score represent independent negative predictors of CGRP‐mAbs response. A ≥50% reduction of headache days/month was observed after olanzapine treatment in 67% of patients with Ref‐M not responsive to CGRP‐mAbs.

Conclusions

We outline that higher frequency of migraine attacks, medication overuse and pain catastrophizing characterize patients with Ref‐M not responsive to CGRP‐mAbs. In this frame, olanzapine effectiveness on frequency and pain intensity of migraine attacks supports the hypothesis that migraine refractoriness may be subtended by a prominent involvement of the dopaminergic pathway.

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.

Structural brain network characteristics in patients with episodic and chronic migraine

Background

Migraine is a primary headache disorder that can be classified into an episodic (EM) and a chronic form (CM). Network analysis within the graph-theoretical framework based on connectivity patterns provides an approach to observe large-scale structural integrity. We test the hypothesis that migraineurs are characterized by a segregated network.

Methods

19 healthy controls (HC), 17 EM patients and 12 CM patients were included. Cortical thickness and subcortical volumes were computed, and topology was analyzed using a graph theory analytical framework and network-based statistics. We further used support vector machines regression (SVR) to identify whether these network measures were able to predict clinical parameters.

Results

Network based statistics revealed significantly lower interregional connectivity strength between anatomical compartments including the fronto-temporal, parietal and visual areas in EM and CM when compared to HC. Higher assortativity was seen in both patients’ group, with higher modularity for CM and higher transitivity for EM compared to HC. For subcortical networks, higher assortativity and transitivity were observed for both patients’ group with higher modularity for CM. SVR revealed that network measures could robustly predict clinical parameters for migraineurs.

Conclusion

We found global network disruption for EM and CM indicated by highly segregated network in migraine patients compared to HC. Higher modularity but lower clustering coefficient in CM is suggestive of more segregation in this group compared to EM. The presence of a segregated network could be a sign of maladaptive reorganization of headache related brain circuits, leading to migraine attacks or secondary alterations to pain.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10194-021-01216-8.

Cerebral cortical dimensions in headache sufferers aged 50 to 66 years: a population-based imaging study in the Nord-Trøndelag Health Study (HUNT-MRI)

Based on previous clinic-based magnetic resonance imaging studies showing regional differences in the cerebral cortex between those with and without headache, we hypothesized that headache sufferers have a decrease in volume, thickness, or surface area in the anterior cingulate cortex, prefrontal cortex, and insula. In addition, exploratory analyses on volume, thickness, and surface area across the cerebral cortical mantle were performed. A total of 1006 participants (aged 50-66 years) from the general population were selected to an imaging study of the head at 1.5 T (HUNT-MRI). Two hundred eighty-three individuals suffered from headache, 80 with migraine, and 87 with tension-type headache, whereas 309 individuals did not suffer from headache and were used as controls. T1-weighted 3D scans of the brain were analysed with voxel-based morphometry and FreeSurfer. The association between cortical volume, thickness, and surface area and questionnaire-based headache diagnoses was evaluated, taking into consideration evolution of headache and frequency of attacks. There were no significant differences in cortical volume, thickness, or surface area between headache sufferers and nonsufferers in the anterior cingulate cortex, prefrontal cortex, or insula. Similarly, the exploratory analyses across the cortical mantle demonstrated no significant differences in volume, thickness, or surface area between any of the headache groups and the nonsufferers. Maps of effect sizes showed small differences in the cortical measures between headache sufferers and nonsufferers. Hence, there are probably no or only very small differences in volume, thickness, or surface area of the cerebral cortex between those with and without headache in the general population.

Brain Structural and Functional Imaging Findings in Medication-Overuse Headache

This chapter overviews research neuroimaging findings of patients with medication-overuse headache (MOH). Results indicate; (i) correlations between neuropathology and medication-overuse; (ii) changes in brain morphology and cortical function; and (iii) brain recovery subsequent to withdrawal of medication that was overused. Results of this narrative review indicate exacerbated brain structural and functional changes in regions of the pain-matrix and in regions of the mesocortical-limbic circuit in patients with MOH compared to patients with migraine or compared to healthy controls. Modification of brain morphology as well as an association between brain recovery and medication withdrawal suggest that the MOH disease process involves state (brain modification) and trait-like (brain adaptation and recovery) neuromechanisms.

Pathophysiology, prevention, and treatment of medication overuse headache

Regular or frequent use of analgesics and acute antimigraine drugs can increase the frequency of headache, and induce the transition from episodic to chronic headache or medication overuse headache. The 1-year prevalence of this condition in the general population is between 1% and 2%. Medication overuse headache is more common in women and in people with comorbid depression, anxiety, and other chronic pain conditions. Treatment of medication overuse headache has three components. First, patients need education and counselling to reduce the intake of medication for acute headache attacks. Second, some patients benefit from drug withdrawal (discontinuation of the overused medication). Finally, preventive drug therapy and non-medical prevention might be necessary in patients at onset of treatment or in patients who do not respond to the first two steps. The optimal therapeutic approach requires validation in controlled trials.

Increased cerebral responses to salient transitions between alternating stimuli in chronic migraine with medication overuse headache and during migraine attacks

Introduction

In a previous study exploring central pain modulation with heterotopic stimuli in healthy volunteers, we found that transitions between sustained noxious and innocuous thermal stimulations on the foot activated the “salience matrix”. Knowing that central sensory processing is abnormal in migraine, we searched in the present study for possible abnormalities of these salient transitional responses in different forms of migraine and at different time points of the migraine cycle.

Methods

Participants of both sexes, mostly females, took part in a conditioned pain modulation experiment: Migraineurs between (n = 14) and during attacks (n = 5), chronic migraine patients with medication overuse headache (n = 7) and healthy volunteers (n = 24). To evoke the salience response, continuous noxious cold or innocuous warm stimulations were alternatively applied on the right foot. Cerebral blood oxygenation level dependent responses were recorded with fMRI.

Results

Switching between the two stimulations caused a significant transition response in the “salience matrix” in all subject groups (effect of the condition). Moreover, some group effects appeared on subsequent post-hoc analyses. Augmented transitional blood oxygenation level dependent responses in the motor cortex and superior temporal sulcus were found in two patient groups compared to healthy controls: chronic migraine with medication overuse headache patients and migraineurs recorded during an attack. In chronic migraine with medication overuse headache patients, salience-related responses were moreover greater in the premotor cortex, supplementary motor area, lingual gyrus and dorso-medial prefrontal cortex and other “salience matrix” areas, such as the anterior cingulate and primary somatosensory cortices.

Conclusion

This study shows salience-related hyperactivation of affective and motor control areas in chronic migraine with medication overuse headache patients and, to a lesser extent, in episodic migraine patients during an attack. The greater extension of exaggerated blood oxygenation level dependent responses to unspecific salient stimuli in chronic migraine with medication overuse headache than during a migraine attack could be relevant for headache chronification.

Morphometric changes over the whole brain in caffeine-containing combination-analgesic-overuse headache

Objective

To investigate brain morphometric changes in medication-overuse headache with excessive intake of caffeine-containing combination analgesics.

Materials and methods

We recruited 32 medication-overuse headache patients overusing caffeine-containing combination analgesics and 26 normal controls with matched sex and age. Magnetic resonance T1-weighted images were processed by automatic volume algorithm of brain regions over the whole brain according to the neuromorphometrics template. We explored the volume differences between groups and correlation with clinical variables.

Results

Medication-overuse headache patients demonstrated decreased volume in cerebellum, optic chiasm, and increased volume in right lateral orbital gyrus, left calcarine, bilateral middle occipital gyrus, right superior parietal lobe, and right temporal transverse gyrus compared with normal controls. The increased volume was primarily contributed by patients of lower headache frequency (10–20 days/month) and with no psychological comorbidities. In regression analyses, the volume of bilateral middle occipital gyrus had negative association with migraine duration, and the volume of right lateral orbital gyrus and right superior parietal lobe was negatively correlated with number of medications per month.

Conclusions

Volume changes of brain regions involved in affective and cognitive processing, visual and auditory perception, and pain sensory/discrimination suggested a particular role of those regions in the pathogenesis of medication-overuse headache overusing caffeine-containing combination analgesics. Morphometric changes in multiple visual processing areas and volume gain in lower headache frequency and less anxiety and depression may be specific features related to overusing caffeine-containing combination analgesics.

Medication-overuse headache: a widely recognized entity amidst ongoing debate

Medication overuse in primary headache disorders is a worldwide phenomenon and has a role in the chronification of headache disorders. The burden of disease on individuals and societies is significant due to high costs and comorbidities. In the Third Edition of the International Classification of Headache Disorders, medication-overuse headache is recognized as a separate secondary entity next to mostly primary headache disorders, although many clinicians see the disease as a sole complication of primary headache disorders. In this review, we explore the historical background of medication-overuse headache, its epidemiology, phenomenology, pathophysiology and treatment options. The review explores relevant unanswered questions and summarizes the current debates in medication-overuse headache.

Lower hippocampal subfields volume in relation to anxiety in medication-overuse headache

Background Hippocampus (HIP) was an important limbic structure, and concurrent emotion disorders may occur in medication-overuse headache patients. The aim of this study is to investigate altered HIP and HIP subfields volume in relation with the anxiety in medication-overuse headache patients using a state-of-the-art hippocampal segment method. Results The current study presented that a significant lower HIP and HIP subfields volume were identified in medication-overuse headache compared with that in normal controls except right HIP tail, bilateral parasubiculums, and HIP fissure. The left HIP and right subiculum presented negative correlation with headache variables, and the right subiculum, Cornu Ammonis 4, granule cell layer of dentate gyrus, bilateral Cornu Ammonis 1, molecular layer, and whole HIP presented negative correlation with Hamilton Anxiety Scale score, which were further confirmed by the linear regression analysis with the exclusion of psychological variables and headache variables, respectively. Conclusions The lower HIP and HIP subfields volume were identified in medication-overuse headache patients, and negatively related with anxiety condition. The potential mechanism for the comorbidity medication-overuse headache and anxiety might be interpreted as the reciprocal causation relationship and co-occurrence relationship.

Less Cortical Thickness in Patients With Persistent Post-Traumatic Headache Compared With Healthy Controls: An MRI Study

OBJECTIVE

To investigate differences in cortical thickness in patients with persistent post-traumatic headache (PPTH) relative to healthy controls and to interrogate whether cortical morphology relates to headache burden (headache frequency, years with post-traumatic headache, PTH) in patients with PPTH.

BACKGROUND

PTHs are one of the most common symptoms following concussion. In some patients, PTHs continue for longer than three months and are classified as PPTH. This study has two main goals: (1) To delineate the neuropathology of PPTH, by interrogating differences in cortical thickness in patients with PPTH relative to healthy controls. (2) To interrogate potential associations between brain morphology and headache burden in patients with PPTH by examining whether cortical thickness relates to frequency of headaches or years lived with PTH.

METHODS

Adults with PPTH diagnosed according to ICHD 3 beta diagnostic criteria and healthy controls underwent brain MRI on a 3 Tesla scanner. Vertex-by-vertex whole brain estimates of cortical thickness were automatically calculated using FreeSurfer v5.3. Differences in cortical thickness in patients with PPTH relative to healthy controls were determined using a general linear model design. Associations were explored between regional clusters where patients with PPTH showed cortical thickness differences compared with healthy controls with headache frequency and years lived with PPTH.

RESULTS

This study included 33 patients with PPTH and 33 healthy control subjects (healthy controls: median age = 33.0, IQR = 15.5; patients with PPTH: median age = 36.0, IQR = 20.5; P = .56). Patients with PPTH had less cortical thickness relative to healthy controls in the left and right superior frontal, caudal middle frontal, and precentral cortex as well as less cortical thickness in the right supramarginal, right superior and inferior parietal, and right precuneus region (P < .05, Monte Carlo corrected for multiple comparisons). There were no regions where patients with PPTH had more cortical thickness relative to healthy controls. A correlation analysis of regions that showed less cortical thickness in patients with PPTH demonstrated a negative correlation between left and right superior frontal thickness with headache frequency (P < .05). There was no association between regional cortical thickness and years lived with PPTH.

CONCLUSION

Compared with healthy controls, patients with PPTH had less cortical thickness in bilateral frontal regions and right hemisphere parietal regions. For patients with PPTH, more frequent headaches were related to less thickness in the left and right superior frontal regions, potentially indicating that brain morphology changes in the superior frontal regions in patients with PPTH are modified by headache frequency.