Right-to-left shunt does not increase white matter lesion load in migraine with aura patients

Cerebrovascular reactivity and deep white matter hyperintensities in migraine: A prospective CO2 targeting study

Several studies suggested the association of migraine with deep white matter hyperintensities (WMHs). We aimed to explore the cerebrovascular reactivity (CVR), deep WMH burden, and their association in patients with migraine using a state-of-the-art methodology. A total of 31 patients with migraine without aura and 31 age/sex-matched controls underwent 3T MRI with prospective end-tidal carbon dioxide (CO₂) targeting. We quantified deep WMH clusters using an automated segmentation tool and measured voxel-wise CVR by changes in blood oxygen level-dependent signal fitted to subjects' end-tidal CO₂. The association of migraine and CVR with the presence of WMH in each voxel and interaction of migraine and CVR on WMH were analysed. Patients had a higher number of deep WMHs than controls (p = 0.015). Migraine and reduced CVR were associated with increased probability of having WMHs in each voxel (adjusted OR 30.78 [95% CI 1.89-500.53], p = 0.016 and adjusted OR 0.30 [0.29-0.32], p < 0.001, respectively). Migraine had an effect modification on CVR on deep WMHs (p for interaction <0.001): i.e. the association between CVR and WMH was greater in patients than in controls. We suggest that the migraine-WMH association can be explained by the effect modification on the CVR.

Evaluating the relationship between right-to-left shunt and white matter hyperintensities in migraine patients: A systematic review and meta-analysis

Introduction

White matter hyperintensities (WMHs) have been observed with greater frequency in patients with migraine and are thought to be associated with impaired cognition and function. The relationship between WMHs and right-to-left shunt (RLS) in migraine patients is unknown. We performed a systematic review to determine if there is an association between RLS and WMHs in patients with migraine.

Methods

A systematic search of the literature was performed in PubMed and Embase using a suitable keyword search strategy from inception up to 16th June 2021. All studies that included patients with migraine and studied RLS and WMHs were included.

Results

A total of 8 non-randomized observational studies comprising 1125 patients with migraine were included; 576 had an RLS, compared to 549 patients with no RLS. The mean age of the study populations ranged from 28.4 to 43 years, while the average duration from migraine diagnosis ranged from 5.1 to 19 years. The proportion of female to male patients was consistently higher in all studies (60.0–94.4%). Amongst migraine patients with RLS, 338 patients (58.7%) had WMHs. In contrast, 256 (46.6%) of migraine patients without RLS had WMHs. RLS was significantly associated with the presence of WMHs in migraine patients (OR: 1.56, 95% CI: 1.05–2.34, p = 0.03).

Conclusion

In migraine patients, RLS was significantly associated with the presence of WMHs. Longitudinal studies are warranted to establish RLS as a risk factor for WMHs in patients with migraine, and to establish the significance of these changes.

Patent foramen ovale

Patent foramen ovale (PFO) is the most common anatomical cause of an interatrial shunt. It is usually asymptomatic but may cause paradoxical embolism, manifesting as stroke, myocardial infarction or visceral/peripheral ischaemia. PFO is a risk factor for stroke and may be associated with migraine with aura. New evidence suggests PFO closure reduces the risk of recurrent ischaemic stroke in a highly selected population of stroke survivors: those aged 60 years or younger with a cryptogenic stroke syndrome, a large right-to-left shunt, an atrial septal aneurysm and no evidence of atrial fibrillation. They benefit from percutaneous PFO closure in addition to antiplatelet therapy, rather than antiplatelet therapy alone. Current evidence does not support PFO closure in the treatment of migraine.

White Matter Hyperintensities in Patients with Sporadic Hemiplegic Migraine

BACKGROUND AND PURPOSE

To identify the differences in overall occurrence, location, and disease burden of white matter hyperintensities (WMH) in patients with sporadic hemiplegic migraine (SHM) and patients with migraine headaches.

METHODS

We included patients who met diagnostic criteria proposed by the third International Classification of Headache Disorders (ICHD-3) for SHM and migraine headache. WMHs were identified using T2 fluid-attenuated inversion recovery axial sequence and classified based upon the location. The disease burden was assessed using Scheltens visual rating scale.

RESULTS

Fifty patients met the diagnostic criteria for SHM and 100 patients for migraine headache. Patients in the study group were similar to the control group in terms of age (47.7 ± 12.2 years vs. 48.17 ± 9.7 years; P = .814) and gender (M: F; 14:36 vs. M: F 25:75; P = .693). WMH were found in 28 (56%) patients with SHM and 44 (44%) in patients with migraine headache. The proportion of patients with WMH was not different between the two groups (P = .166). On univariate analysis, the proportion of patients with WMH in parietal, occipital, and infratentorial regions was higher in patients with SHM. White matter burden determined by visual rating scale and proportion of patients with lesions ≥5 mm in diameter was also significantly higher in patients with SHM. On multivariate analysis, the WMH occurrence in the parietal lobe (P = .043) was found to be significantly higher in SHM.

CONCLUSIONS

The WMH occurrence in patients with SHM is significantly more in the parietal lobe when compared to those with migraine headaches. WMH burden was also higher in patients with SHM, and larger white matter lesions occurred more frequently in these patients with SHM (compared to ordinary migraineurs).

Association of white matter hyperintensities with migraine features and prognosis

Background

White matter hyperintensities (WMHs) are frequently detected in migraine patients. However, their significance and correlation to migraine disease burden remain unclear. This study aims to examine the correlation of WMHs with migraine features and explore the relationship between WMHs and migraine prognosis.

Methods

A total of 69 migraineurs underwent MRI scans to evaluate WMHs. Migraine features were compared between patients with and without WMHs. After an average follow-up period of 3 years, these patients were divided into two groups, according to the reduction of headache frequency: improved and non-improved groups. The percentage and degree of WMHs were compared between these two groups.

Results

A total of 24 patients (34.8%) had WMHs. Patients with WMHs were significantly older (39.0 ± 7.9 vs. 30.6 ± 10.4 years, P < 0.001) and had a longer disease duration (median: 180.0 vs. 84.0 months, P = 0.013). Furthermore, 33 patients completed the follow up period (15 patients improved and 18 patients did not improve). Patients in the non-improved group had a higher frequency of WMHs (55.6% vs. 13.3%, P = 0.027) and median WMHs score (1.0 vs. 0.0, P = 0.030).

Conclusions

WMHs can predict unfavorable migraine prognosis. Furthermore, WMHs may have a closer association with age than migraine features.

The relationship between right-to-left shunt and brain white matter lesions in Japanese patients with migraine: a single center study

BACKGROUND

There may be a link between right-to-left shunt (RLs) and brain white matter lesions (WMLs) in patients with migraine. In this study, we assessed the relationship between WMLs and RLs in Japanese migraine patients.

METHODS

A total of 107 consecutive patients with migraine with (MA) and without aura (MWOA) were included in this study. Contrast transcranial Doppler ultrasound was used to detect RLs. WMLs were graded using brain magnetic resonance imaging based on well-established criteria.

FINDINGS

The prevalence of RLs was significantly increased in the WMLs positive group (n = 24) compared with the WMLs negative group (n = 83) (75.0% vs. 47.0%, p = 0.015). In prevalence of WMLs between MA and MWOA patients, there were no statistical differences (p = 0.410). Logistic regression analysis adjusted by age and disease duration of migraine identified an RLs-positive status as the sole determinant for the presence of WMLs (OR = 6.15; 95% CI 1.82-20.8; p = 0.003) CONCLUSION: Our study suggests a possible link between RLs and WMLs in Japanese patients with migraine.

The Migraine-Stroke Connection

Migraine and stroke are common neurovascular disorders which share underlying physiological processes. Increased risks of ischemic stroke, hemorrhagic stroke, and subclinical ischemic lesions have been consistently found in migraineurs. Three possible associations are suggested. One is that underlying pathophysiology of migraine can lead to ischemic stroke. Second, common comorbidities between migraine and stroke can be present. Lastly, some syndromes can manifest with both migraine-like headache and cerebrovascular disease. Future studies should be targeted on bidirectional influence of migraine on different stroke mechanisms and optimal prevention of stroke in migraine patients.

Systemic right-to-left shunts, ischemic brain lesions, and persistent migraine activity

OBJECTIVE

To assess whether migraine in the general population is associated with increased risk of systemic right-to-left shunts (RLS) and whether RLS are associated with increased prevalence of brain infarcts and persistent recurrence of migraine attacks at older age.

METHODS

Brain MRI and transcranial Doppler with air contrast in 166 unselected migraineurs (mean age ± SD 56 ± 7.7 years; 70% women; n = 96 migraine with aura) and 69 controls (mean age ± SD 55 ± 7.6 years; 65% women) from the general population.

RESULTS

Participants with migraine with aura more frequently had Valsalva-induced RLS (60%), in particular large-sized, compared to controls (42%; odds ratio [OR] 2.1; 95% confidence interval [CI] 1.1-3.9; p = 0.02) and participants with migraine without aura (40%; OR 2.3; 95% CI 1.2-4.3; p = 0.01). They also more frequently had spontaneous RLS (35%) than participants with migraine without aura (17%; OR 2.6; 95% CI 1.3-5.6; p = 0.01) but not compared to controls (26%; OR 1.6; 95% CI 0.8-3.1; p = 0.2). Participants with migraine with aura and spontaneous RLS more frequently had persistent migraine activity (85%) than participants with migraine without spontaneous RLS (63%; OR 3.4; 95% CI 1.2-10.1; p = 0.03). Nine percent of participants with RLS had silent posterior circulation infarcts compared to 3% of participants without RLS (OR 2.8; 95% CI 0.9-9.3; p = 0.08), independent of migraine status. RLS were not associated with white matter lesions.

CONCLUSIONS

RLS are more prevalent in migraineurs with aura but do not explain the increased prevalence of silent posterior circulation infarcts or white matter lesions in migraineurs. Spontaneous RLS are associated with persistent migraine.

Patent Foramen Ovale and Migraine: Closing the Debate--A Review

BACKGROUND

A link between patent foramen ovale (PFO) and migraine as well as the utility of closure of PFO and its effect on migraine have been subjects of debate. The present review is an effort to gather the available evidence on this topic and formulate recommendations.

METHODS

A systematic search of electronic databases (Medline, Embase, Cochrane Library) was performed. A separate search in associated reference lists of identified studies was done. Observational studies and clinical trials published in English using the International Headache Society criteria for diagnosis of migraine were included in the analysis. The search was performed in 3 categories: prevalence of migraine in patients with PFO, prevalence of PFO in migraine patients, and effect of PFO closure and its effect on migraine. The quality of evidence and strength of recommendations during review of these studies was analyzed.

RESULTS

About 14 observational studies with 2602 subjects who had PFO were identified. Migraine prevalence ranged from 16% to 64%. Another 20 studies reported 2444 patients with migraine; the prevalence of PFO ranged from 15% to 90%. About 20 observational studies (1194 patients) that examined the effect of PFO closure on migraine were identified. Resolution of migraine was reported in 10% to 83% of patients, improvement in 14% to 83%, no change in 1% to 54%, and worsening in 4% to 8%. The overall quality of these observational studies was poor. Finally, 3 randomized clinical trials included a total of 238 patients who underwent PFO closure compared with 234 patients in the control groups. All 3 trials failed to meet their primary end points defined as migraine resolution and greater than 50% reduction in migraine days at 1 year. In 2 of the clinical trials, there was some benefit noted in a small subset of migraine patients with aura, but the numbers were too small to extrapolate the findings to the general migraine population.

CONCLUSIONS

There is no good quality evidence to support a link between migraine and PFO. Closure of PFO for migraine prevention does not significantly reduce the intensity and severity of migraine. We do not recommend the routine use of this procedure in current practice.

Migraine with aura and patent foramen ovale: myth or reality?

Several observational studies report that subjects with migraine with aura have a higher prevalence of right-to left shunt, commonly due to patent foramen ovale, and that patent foramen ovale is more prevalent in subjects with migraine with aura. Although migraine without aura has been less extensively studied, it does not seem to be associated with an increased prevalence of right-to left shunt. The mechanism that underlies the possible relationship between patent foramen ovale and migraine with aura remains speculative. The proposed mechanisms are migraine-triggering vasoactive chemicals bypassing the pulmonary filter and reaching the cerebral circulation and paradoxical microembolization. However, it is unclear, at this time, if there is a causal or comorbid association between the two conditions. In some families atrial shunts show a dominant inheritance that seems to be linked to inheritance of migraine with aura. Migraine with aura is an independent risk factor for ischemic stroke, and patent foramen ovale is present more frequently in patients with cryptogenic stroke than in controls. At this moment, there is no convincing evidence that excess stroke risk of migraine is simply mediated by patent foramen ovale through paradoxical embolism. Several non-controlled studies suggest that closure of the foramen ovale significantly reduces attack frequency in migraine patient, but the only prospective placebo-controlled trial does not support these results. Patent foramen ovale closure, at present, is not indicated as a treatment for migraine in clinical practice.

White matter lesions in children and adolescents with migraine

BACKGROUND

The etiology and clinical importance of white matter lesions in migraine remain poorly understood. To understand these issues more fully, we reviewed the brain magnetic resonance imaging scans of pediatric patients and assessed the relationships between white matter lesions, migraine type, patent foramen ovale, and right-to-left shunting.

METHODS

The magnetic resonance imaging scans of a cohort of children (n = 89) and adolescents, ages 6 to 18 years, who participated in a study of migraine and patent foramen ovale were reviewed. All children in the cohort had undergone saline contrast transthoracic echocardiography and transcranial Doppler studies.

RESULTS

White matter lesions were detected in 15 of the 89 patients (17%). White matter lesions were small (<5 mm) in the majority (10/15; 66%). We observed no relationship between the presence of white matter lesions and (1) migraine type (six patients with white matter lesions among 35 with migraine with aura [17%] vs. nine with white matter lesions among 54 without aura [17%]; P = 1.0); (2) patent foramen ovale (five with white matter lesions among 35 with patent foramen ovale [14%] vs. 10 with white matter lesions among 54 without patent foramen ovale [19%]; P = 0.77); or (3) shunt size (two large shunts in 15 with white matter lesions [13%] vs. nine large shunts among 72 without white matter lesions [13%]; P = 1.0).

CONCLUSIONS

These results indicate that small white matter lesions are not infrequent in children and adolescents with migraine. However, no relationships between white matter lesions and migraine type, patent foramen ovale, or degree of right-to-left shunting were observed.

Recent progress in migraine pathophysiology: role of cortical spreading depression and magnetic resonance imaging

Migraine is characterised by debilitating pain, which affects the quality of life in affected patients in both the western and the eastern worlds. The purpose of this article is to give a detailed outline of the pathophysiology of migraine pain, which is one of the most confounding pathologies among pain disorders in clinical conditions. We critically evaluate the scientific basis of various theories concerning migraine pathophysiology, and draw insights from brain imaging approaches that have unraveled the prevalence of cortical spreading depression (CSD) in migraine. The findings supporting the role of CSD as a physiological substrate in clinical pain are discussed. We also give an exhaustive overview of brain imaging approaches that have been employed to solve the genesis of migraine pain, and its possible links to the brainstem, the neocortex, genetic endophenotypes, and pathogenetic factors (such as dopaminergic hypersensitivity). Furthermore, a roadmap is proposed to provide a better understanding of pain pathophysiology in migraine, to enable the development of strategies using leads from brain imaging studies for the identification of early biomarkers, efficient prognosis, and treatment planning, which eventually may help in alleviating some of the devastating impact of pain morbidity in patients afflicted with migraine.

Right-to-left shunts as a cause of juxtacortical spots in patients with migraine

BACKGROUNDS

Juxtacortical spots on fluid-attenuated inversion recovery (FLAIR) images can be frequently detected in patients with migraine. However, the origins of the cerebral lesions (including juxtacortical spots on FLAIR images) found in the previous studies are not known. We sought to investigate the association between juxtacortical spots on FLAIR images and right-to-left shunt (RLS) in migraine patients.

METHODS

Juxtacortical spots on FLAIR images were arbitrarily defined as small areas of hyperintensities in the juxtacortex and cortico-subcortical junction. The presence of RLS was examined by a transcranial Dopper (TCD) with the agitated saline test. The degree of RLS was categorized into four grades according to the number of microemboli: no shunt, <10 microbubbles (MB), >10 MB single spots pattern, and >10 MB shower/curtain pattern. We compared the results for migraine patients (n = 49) with those for healthy controls (n = 49).

RESULTS

Juxtacortical spots on FLAIR images occurred in 38/98 subjects; of them, 27/49 (55.1%) had migraines and 11/49 (22.2%) were healthy controls (P = 0.002). The independent factors associated with juxtacortical spots on FLAIR images were female, migraine patients, and RLS by multivariate analysis. In migraine patients, RLS was independently associated with juxtacortical spots on FLAIR images.

CONCLUSION

Our results suggest that juxtacortical spots on FLAIR images were frequently found in migraine patients and might be associated with the presence of RLS in those patients. Further studies are needed to assess whether juxtacortical spots have clinical implications in patients with migraine.

White matter lesions progression in migraine with aura: a clinical and MRI longitudinal study

OBJECTIVE

To prospectively evaluate longitudinal changes in white matter lesions (WMLs) in migraineurs with aura, by magnetic resonance imaging (MRI), and to correlate WMLs modifications with patients' clinical characteristics.

METHODS

Forty-one consecutive migraineurs with aura were followed for a mean time of 33.2 months. Patients underwent MRI at baseline and follow-up and were evaluated for cerebrovascular risk factors. Presence of WMLs on MRI was assessed by two neuroradiologists.

RESULTS

WMLs were present in 26 subjects (63.4%) at baseline MRI. At follow-up a total of 8 patients had new WMLs (19.5%). There was a significant correlation between aura duration and number of new WMLs, and between the number of migraine attacks with aura and new WMLs.

CONCLUSIONS

Our study demonstrates that in migraine with aura WMLs number can progress over time and suggests an association between aura features and WMLs progression. Studies with a higher number of patients are required to confirm these findings.

Role of patent foramen ovale in migraine etiology and treatment: a review

An increased prevalence between patent formen ovale (PFOs) and migraine exists but there is conflicting data regarding causal relationship between these two conditions. It is controversial whether cardiac screening and intervention like PFO closure provides any benefit in this population and so this area still remains under intense investigation. The management of migraine lies at the intersection between the practice of primary care physicians, neurologists, and cardiologists. There is no consensus as to what is the best practice for the evaluation of these patients with difficult to control migraine given the millions of dollars spent on physician visits and pharmacotherapy. This review seeks to summarize the current literature on this association and studies that have investigated PFO closure in this population.

Intersection between metabolic dysfunction, high fat diet consumption, and brain aging

Deleterious neurochemical, structural, and behavioral alterations are a seemingly unavoidable aspect of brain aging. However, the basis for these alterations, as well as the basis for the tremendous variability in regards to the degree to which these aspects are altered in aging individuals, remains to be elucidated. An increasing number of individuals regularly consume a diet high in fat, with high-fat diet consumption known to be sufficient to promote metabolic dysfunction, although the links between high-fat diet consumption and aging are only now beginning to be elucidated. In this review we discuss the potential role for age-related metabolic disturbances serving as an important basis for deleterious perturbations in the aging brain. These data not only have important implications for understanding the basis of brain aging, but also may be important to the development of therapeutic interventions which promote successful brain aging.

Stroke in patients with migraine

BACKGROUND AND PURPOSE

Migraine with aura (MA) is considered as a risk factor for ischaemic stroke. The present observational retrospective study compares migraine patients admitted for a documented stroke with those presenting focal neurological symptoms and headache without a demonstrable lesion and in which the final diagnosis was a migraine attack with aura.

MATERIAL AND METHODS

The study included 14 migraine patients with a stroke and 37 without a stroke. The clinical characteristics, the vascular risk factors and the results of the technical examinations were compared.

RESULTS

Stroke occurred in migraine patients with aura as well as without aura. Classical vascular risk factors were rather rare. Patent foramen ovale (PFO) with or without atrial septum aneurysm appeared to be the main risk factor for stroke in patients with a history of migraine. Infarcts were mainly located in the supratentorial territory of the posterior cerebral circulation. Also some lobar haematomas were observed, but their aetiology remained uncertain. The strokes were generally mildly severe with good outcome. Hyperintense signals in the cerebral white matter and cerebellum, on T2-weighted magnetic resonance imaging, were more frequent in the migraine patients with stroke.

CONCLUSIONS

The presence of PFO, rather than of MA, appeared to be the main risk factor for stroke patients with migraine. No direct relation between migraine and stroke could be demonstrated.

Cerebral distribution of white matter lesions in migraine with aura patients

OBJECTIVE

The objective of the study was to compare the cerebral distribution of white matter lesions (WMLs) between migraine patients with different aura symptoms.

METHODS

Migraine with aura (MA) patients were consecutively enrolled as part of the Shunt-Associated Migraine (SAM) study. According to clinical symptoms, aura was classified as motor, aphasic, sensory, visual or vertebrobasilar. Standard and FLAIR (fluid attenuated inversion recovery) T(2)-weighted MRI sequences were inspected for WMLs by three independent raters blinded to clinical data. WMLs were assessed in the periventricular areas (PV-WMLs) with the Fazekas scale and in the deep white matter (D-WMLs) with the Schelten's scale. Interobserver agreement was good to excellent (k = 0.64 to 0.96, p < .0001).

RESULTS

One hundred and eighty-five patients (77% women) were included. Aura symptoms were classified as visual in 172 (99%) patients, sensory in 76 (42%), aphasic in 54 (30%), motor in 39 (21%) and vertebrobasilar in 17 (9%) patients. One hundred and four patients (57%) exhibited more than one type of aura. D-WMLs were mainly detected in the frontal lobes (86%). There was no association between type of aura and the presence of WMLs in any cerebral location.

CONCLUSION

Aura symptoms do not influence the cerebral distribution of WMLs associated with migraine disease.

Usefulness of transcatheter patent foramen ovale closure in migraineurs with moderate to large right-to-left shunt and instrumental evidence of cerebrovascular damage

Transcatheter patent foramen ovale (PFO) closure might be effective in improving migraines. To assess the efficacy of PFO closure in migraineurs with a moderate to large right-to-left shunt and instrumental evidence of embolic cerebral damage, 76 highly symptomatic migraineurs were prospectively investigated. The presenting clinical syndrome was stroke in 16 patients, repeated transient ischemic attack in 32 patients, and lone migraine associated with cerebral ischemic lesions on magnetic resonance imaging in 28 patients. Migraine severity was assessed before PFO closure and monthly for 6 months after discontinuation of antiplatelet therapy. At the end of 12 months of follow-up, the averaged postprocedural total score was compared with the baseline score. Transcatheter PFO closure was successful in all patients, and the 12-month PFO closure rate was 97%. The baseline total migraine score was similar in patients with stroke, transient ischemic attack, and lone migraine (6.8 +/- 1.6, 6.7 +/- 1.4, and 6.9 +/- 1.7 respectively, p = NS). After a mean follow-up of 13.7 +/- 2.4 months, no recurrent cerebrovascular episodes had occurred. At the end of the follow-up period, a significant reduction in the total migraine score was observed in all groups, regardless of the initial clinical presentation. Migraine was completely abolished in 35 patients (46%), improved in 27 (36%), and unchanged in 14 (18%). The proportion of patients with migraine suppression and improvement was similar in the 3 groups. In conclusion, in highly symptomatic migraineurs with previous ischemic cerebral events and instrumental evidence of cerebral embolism, transcatheter PFO closure can result in improvement of migraine severity in a high percentage of patients.

Diagnostic testing for migraine and other primary headaches

Most primary headaches can be diagnosed using the history and examination. Judicious use of neuroimaging and other testing, however, is indicated to distinguish primary headaches from the many secondary causes that may share similar features. This article evaluates the reasons for diagnostic testing and the use of neuroimaging, electroencephalography, lumbar puncture, and blood testing. The use of diagnostic testing in adults and children who have headaches and a normal neurologic examination, migraine, trigeminal autonomic cephalalgias, hemicrania continua, and new daily persistent headache are reviewed.

Advances in the basic and clinical science of migraine

Migraine continues to be an elephant in the room of medicine: massively common and a heavy burden on patients and their healthcare providers, yet the recipient of relatively little attention for research, education, and clinical resources. Its visibility is gradually increasing, however, as advances in genetics, imaging, epidemiology, and pharmacology produce a more definitive understanding of the condition, and identify more specific and effective treatments. Rapid evolution of concepts regarding its prevalence, pathophysiology, and clinical management is leading to growing recognition of migraine as a fundamentally important disorder of the nervous system.

Morphing voxels: the hype around structural imaging of headache patients

Neuroimaging analysis using structural data has begun to provide insights into the pathophysiology of headache syndromes. Several independent studies have suggested a decrease in grey matter in pain-transmitting areas in migraine patients. Most of these data are discussed as damage or loss of brain grey matter, reinforcing the idea of migraine as a progressive disease. However, given what we know about the nature of morphometric changes detectable by the methods we have to date, this interpretation is highly speculative and not supported by the data. It is likely that these changes are the consequence and not the cause of the respective headache syndromes, as they are probably not irreversible and only mirror the proportion or duration of pain suffered. Moreover, structural changes are not headache specific and have to be seen in the light of a wealth of pain studies using these methods. The studies in cluster headache patients prompted the use of stereotactic stimulation of the hypothalamic target point identified by functional and structural neuroimaging. Due to the nature of the methods used and due to a high anatomical variance it is more than questionable to use this point as a definite answer to the source of the headache in clusters and even more so when it is uncritically used in individuals. We need a way to study each patient individually using the functional imaging method with the highest spatial and temporal resolution available to enable us to target the seed point for deep brain stimulation on this individual basis. One of the major future challenges is to understand the behavioural consequences and cellular mechanisms underlying neuroanatomic changes in pain and headache.