Neuroimaging in the pre-ictal or premonitory phase of migraine: a narrative review

Prediction models for treatment response in migraine: a systematic review and meta-analysis

BACKGROUND

Migraine is a complex neurological disorder with significant clinical variability, posing challenges for effective management. Multiple treatments are available for migraine, but individual responses vary widely, making accurate prediction crucial for personalized care. This study aims to examine the use of statistical and machine learning models to predict treatment response in migraine patients.

METHODS

A systematic review and meta-analysis were conducted to assess the performance and quality of predictive models for migraine treatment response. Relevant studies were identified from databases such as PubMed, Cochrane Register of Controlled Trials, Embase, and Web of Science, up to 30th of November 2024. The risk of bias was evaluated using the PROBAST tool, and adherence to reporting standards was assessed with the TRIPOD + AI checklist.

RESULTS

After screening 1,927 documents, ten studies met the inclusion criteria, and six were included in a quantitative synthesis. Key data extracted included sample characteristics, intervention types, response outcomes, modeling methods, and predictive performance metrics. A pooled analysis of the area under the curve (AUC) yielded a value of 0.86 (95% CI: 0.67-0.95), indicating good predictive performance. However, the included studies generally had a high risk of bias, particularly in the analysis domain, as assessed by the PROBAST tool.

CONCLUSION

This review highlights the potential of statistical and machine learning models in predicting treatment response in migraine patients. However, the high risk of bias and significant heterogeneity emphasize the need for caution in interpretation. Future research should focus on developing models using high-quality, comprehensive, and multicenter datasets, rigorous external validation, and adherence to standardized guidelines like TRIPOD + AI. Incorporating multimodal magnetic resonance imaging (MRI) data, exploring migraine symptom-treatment interactions, and establishing uniform methodologies for outcome measures, sample size calculations, and missing data handling will enhance model reliability and clinical applicability, ultimately improving patient outcomes and reducing healthcare burdens.

TRIAL REGISTRATION

PROSPERO, CRD42024621366.

Brain connectivity in individuals with migraine resets during the headache phase: a whole-brain connectivity study

Episodic migraine is reflected by cyclic changes in behavior and cortical processing. We aimed to identify how functional connectivity changes over the entire migraine cycle. By using longitudinal neuroimaging and a whole-brain connectivity analysis approach, we tested 12 episodic migraine patients across 82 functional MRI recordings during spontaneous migraine headaches with follow-up measurements over the pain-free interval without any external stimulation. We found that the functional connectivity linearly increased over the interictal interval. In the prodromal phase, we observed the strongest connections between the anterior agranular insula and the posterior orbitofrontal cortex with sensory, motor and cingulate areas. The strength of the connections dropped during the headache. Peak connectivity during the prodromal phase and its collapse during the headache can be regarded as a mechanism of normalizing cortical processing. We speculate about a malfunction at the molecular level in agranular frontal and insular regions, which needs to be addressed in subsequent studies.

Alterations of White Matter Microstructure in Migraine Patients Vary in the Peri-ictal Phases

Alterations in white matter (WM) microstructure are commonly found in migraine patients. Here, we employ a longitudinal study of episodic migraine without aura using diffusion magnetic resonance imaging (dMRI) to investigate whether such WM microstructure alterations vary through the different phases of the pain cycle. Fourteen patients with episodic migraine without aura related with menstruation were scanned through four phases of their (spontaneous) migraine cycle (interictal, preictal, ictal, and postictal). Fifteen healthy controls were studied in the corresponding phases of the menstrual cycle. Multishell dMRI data were acquired and preprocessed to obtain maps of diffusion parameters reflecting WM microstructure. After a whole-brain analysis comparing patients with controls, a region-of-interest analysis was performed to determine whether the patients' microstructural changes varied across the migraine cycle in specific WM tracts. Compared with controls, patients showed reduced axial diffusivity (AD) in several WM tracts across the whole brain in the interictal phase and increased fractional anisotropy (FA) in commissural fibers in the ictal phase. Interestingly, AD returned to baseline levels during peri-ictal phases in specific projection and association fibers. In contrast, FA values decreased in the ictal phase away from normal values in a few commissural and projection tracts. Widespread WM fiber tracts suffer structural variations across the migraine cycle, suggesting microstructural changes potentially associated with limbic and salience functional networks and highlighting the importance of the cycle phase in imaging studies of migraine.

Relationship between food triggers and sensory hypersensitivity in patients with migraine

BACKGROUND

 The recognition of food as the trigger of attacks occurs in approximately 25% of individuals with migraine. However, differentiating migraine food triggers and prodrome symptoms is still a challenge.

OBJECTIVE

 To understand the association of clinical characteristics of migraine with food triggers and to identify predictors of food triggers.

METHODS

 Patients with migraine diagnosed according to the criteria of the third edition of the International Classification of Headache Disorders (ICHD-3) were evaluated for the presence or absence of food triggers.

RESULTS

 In total, 502 patients with migraine were investigated, and they were divided into two groups: those with food triggers (58.4%) and those without food triggers (41.6%). The main food triggers were alcohol (44%), chocolate (42%), cheese (27.7%), excess carbohydrates (27.7%), coffee (21.8%), cold cuts (16%), and citrus fruits (11.9%). Aura and excessive use of analgesics were more frequent among patients with food triggers (p = 0.022). Photophobia and osmophobia were associated with the presence of a food trigger (p < 0.001). There was a greater impact of migraine in the presence of food triggers (p = 0.002). Through binary logistic regression, we identified clinical predictors of food triggers, such as photophobia and osmophobia.

CONCLUSION

 The presence of a food trigger was significantly associated with photophobia and osmophobia. Osmophobia might be another mechanism by which patients perceive foods as triggers for their migraine attacks.

Hallmarks of primary headache: part 1 - migraine

BACKGROUND AND AIM

Migraine is a common disabling conditions which, globally, affects 15.2% of the population. It is the second cause of health loss in terms of years lived with disability, the first among women. Despite being so common, it is poorly recognised and too often undertreated. Specialty centres and neurologists with specific expertise on headache disorders have the knowledge to provide specific care: however, those who do not regularly treat patients with migraine will benefit from a synopsis on the most relevant and updated information about this condition. This paper presents a comprehensive view on the hallmarks of migraine, from genetics and diagnostic markers, up to treatments and societal impact, and reports the elements that identify migraine specific features.

MAIN RESULTS

The most relevant hallmark of migraine is that it has common and individual features together. Besides the known clinical manifestations, migraine presentation is heterogeneous with regard to frequency of attacks, presence of aura, response to therapy, associated comorbidities or other symptoms, which likely reflect migraine heterogeneous genetic and molecular basis. The amount of therapies for acute and for prophylactic treatment is really wide, and one of the difficulties is with finding the best treatment for the single patient. In addition to this, patients carry out different daily life activities, and might show lifestyle habits which are not entirely adequate to manage migraine day by day. Education will be more and more important as a strategy of brain health promotion, because this will enable reducing the amount of subjects needing specialty care, thus leaving it to those who require it in reason of refractory condition or presence of comorbidities.

CONCLUSIONS

Recognizing the hallmarks of migraine and the features of single patients enables prescribing specific pharmacological and non-pharmacological treatments. Medical research on headaches today particularly suffers from the syndrome of single-disease approach, but it is important to have a cross-sectional and joint vision with other close specialties, in order to treat our patients with a comprehensive approach that a heterogeneous condition like migraine requires.

Preserved working memory performance along with subcortical modulation during peri-ictal phases in spontaneous migraine attacks

OBJECTIVE

To analyze cognitive performance and brain activation during a working memory task in patients with migraine during various phases of the migraine cycle and compare to healthy participants.

BACKGROUND

Cognitive difficulties reported during migraine attacks remain poorly understood, despite evidence that the lateral frontoparietal network undergoes reversible disturbances and decreased activation during attacks. Recent findings in resting state functional magnetic resonance imaging suggest that brain areas involved in this network interact with subcortical regions during spontaneous migraine attacks.

METHODS

In this prospective, within-subject study, 10 patients with diagnosed menstrual-related episodic migraine without aura underwent 3T functional magnetic resonance imaging assessments while performing a working memory task across four phases of the natural migraine cycle: peri-ictal (preictal, ictal, postictal) phases and interictally (between attacks). Migraine prophylaxis was an exclusion criterion. Fourteen healthy controls were assessed during the corresponding phases of their menstrual cycles.

RESULTS

The protocol was completed by 24 female participants aged 21 to 47 years: 10 with migraine (four sessions each) and 14 healthy controls (two sessions each) yielding a total of 68 analyzed datasets. Patients and controls showed similar performance on the working memory task and displayed increased brain activity in regions linked to this function, namely the middle frontal gyrus, inferior parietal lobe, and anterior cingulate cortex, during all phases of the migraine/menstrual cycle. Patients with migraine (N = 10) exhibited a significant decrease in hypothalamic activity (p = 0.007) as measured by the percent signal change (PSC) during the postictal phase compared to perimenstrual controls (N = 14), with -2 (16) and 31 (35) PSC, respectively. Comparing across the migraine cycle, the change in hypothalamic activity relative to controls in the postictal phase -0.33 (0.2) ΔPSC was significantly different from the ones in the interictal (0.006 [0.5] ΔPSC; p = 0.002) and preictal (-0.08 [0.4] ΔPSC; p = 0.034) phases.

CONCLUSION

During a working memory task, cognition-related brain activation was present across all phases of the migraine cycle similarly to healthy control participants. Patients with migraine, however, displayed lower neural activity at the subcortical level in the postictal phase. Nonetheless, the sample size is a limitation for the generalization of our results. More research is needed to fully understand how the brain copes with cognitive demands during spontaneous migraine attacks.

Phasic perfusion dynamics among migraine subtypes: a multimodel arterial spin labeling investigation

BACKGROUND

Migraine-related perfusion changes are documented but inconsistent across studies due to limited sample size and insufficient phenotyping. The phasic and spatial dynamics across migraine subtypes remains poorly characterized. This study aimed to determine spatiotemporal dynamics of gray matter (GM) perfusion in migraine.

METHODS

We prospectively recruited episodic (EM) and chronic migraine (CM) patients, diagnosed with the International Headache Society criteria and healthy controls (HCs) between 2021 and 2023 from the headache center in a tertiary medical center, and adjacent communities. Magnetic resonance (3-tesla) arterial spin labeling (ASL) was conducted for whole brain cerebral blood flow (CBF) in all participants. The voxel-wise and whole brain gray matter (GM) CBF were compared between subgroups. Spatial pattern analysis of CBF and its correlations with headache frequency were investigated regarding different migraine phases and subtypes. Sex- and age-adjusted voxel-wise and whole brain GM comparisons were performed between HCs and different EM and CM phases. Spatial pattern analysis was conducted by CBF clusters with phasic differences and spin permutation test. Correlations between headache frequency and CBF were investigated regarding different EM and CM phases.

RESULTS

Totally 344 subjects (172 EM, 120 CM, and 52 HCs) were enrolled. Higher CBF in different anatomical locations was identified in ictal EM and CM. The combined panels of the specific locations with altered CBF in ictal EM on receiver operating characteristic curve analysis demonstrated areas under curve of 0.780 (vs. HCs) and 0.811 (vs. preictal EM). The spatial distribution of ictal-interictal CBF alteration of EM and CM were not correlated with each other (p = 0.665; r = - 0.018). Positive correlations between headache frequency and CBF were noted in ictal EM and CM regarding whole GM and specific anatomical locations.

CONCLUSIONS

Patients with migraine exhibited unique spatiotemporal CBF dynamics across different phases and distinct between subtypes. The findings provide neurobiological insights into how selected anatomical structures engage in a migraine attack and adapt to plastic change of repeated attacks along with chronicity.

Insights from triggers and prodromal symptoms on how migraine attacks start: The threshold hypothesis

BACKGROUND

The prodrome or premonitory phase is the initial phase of a migraine attack, and it is considered as a symptomatic phase in which prodromal symptoms may occur. There is evidence that attacks start 24-48 hours before the headache phase. Individuals with migraine also report several potential triggers for their attacks, which may be mistaken for premonitory symptoms and hinder migraine research.

METHODS

This review aims to summarize published studies that describe contributions to understanding the fine difference between prodromal/premonitory symptoms and triggers, give insights for research, and propose a way forward to study these phenomena. We finally aim to formulate a theory to unify migraine triggers and prodromal symptoms. For this purpose, a comprehensive narrative review of the published literature on clinical, neurophysiological and imaging evidence on migraine prodromal symptoms and triggers was conducted using the PubMed database.

RESULTS

Brain activity and network connectivity changes occur during the prodromal phase. These changes give rise to prodromal/premonitory symptoms in some individuals, which may be falsely interpreted as triggers at the same time as representing the early manifestation of the beginning of the attack. By contrast, certain migraine triggers, such as stress, hormone changes or sleep deprivation, acting as a catalyst in reducing the migraine threshold, might facilitate these changes and increase the chances of a migraine attack. Migraine triggers and prodromal/premonitory symptoms can be confused and have an intertwined relationship with the hypothalamus as the central hub for integrating external and internal body signals.

CONCLUSIONS

Differentiating migraine triggers and prodromal symptoms is crucial for shedding light on migraine pathophysiology and improve migraine management.

Intervening in the Premonitory Phase to Prevent Migraine: Prospects for Pharmacotherapy

Migraine is a common brain condition characterised by disabling attacks of headache with sensory sensitivities. Despite increasing understanding of migraine neurobiology and the impacts of this on therapeutic developments, there remains a need for treatment options for patients underserved by currently available therapies. The first specific drugs developed to treat migraine acutely, the serotonin-5-hydroxytryptamine [5-HT1B/1D] receptor agonists (triptans), seem to require headache onset in order to have an effect, while early treatment during mild pain before headache escalation improves short-term and long-term outcomes. Some patients find treating in the early window once headache has started but not escalated difficult, and migraine can arise from sleep or in the early hours of the morning, making prompt treatment after pain onset challenging. Triptans may be deemed unsuitable for use in patients with vascular disease and in those of older age and may not be effective in a proportion of patients. Headache is also increasingly recognised as being just one of the many facets of the migraine attack, and for some patients it is not the most disabling symptom. In many patients, painless symptoms can start prior to headache onset and can reliably warn of impending headache. There is, therefore, a need to identify therapeutic targets and agents that may be used as early as possible in the course of the attack, to prevent headache onset before it starts, and to reduce both headache and non-headache related attack burden. Early small studies using domperidone, naratriptan and dihydroergotamine have suggested that this approach could be useful; these studies were methodologically less rigorous than modern day treatment studies, of small sample size, and have not since been replicated. The emergence of novel targeted migraine treatments more recently, specifically calcitonin gene-related peptide (CGRP) receptor antagonists (gepants), has reignited interest in this strategy, with encouraging results. This review summarises historical and emerging data in this area, supporting use of the premonitory phase as an opportunity to intervene as early as possible in migraine to prevent attack-related morbidity.

Pathophysiology of Migraine

OBJECTIVE

This article provides an overview of the current understanding of migraine pathophysiology through insights gained from the extended symptom spectrum of migraine, neuroanatomy, migraine neurochemistry, and therapeutics.

LATEST DEVELOPMENTS

Recent advances in human migraine research, including human experimental migraine models and functional neuroimaging, have provided novel insights into migraine attack initiation, neurochemistry, neuroanatomy, and therapeutic substrates. It has become clear that migraine is a neural disorder, in which a wide range of brain areas and neurochemical systems are implicated, producing a heterogeneous clinical phenotype. Many of these neural pathways are monoaminergic and peptidergic, such as those involving calcitonin gene-related peptide and pituitary adenylate cyclase-activating polypeptide. We are currently witnessing an exciting era in which specific drugs targeting these pathways have shown promise in treating migraine, including some studies suggesting efficacy before headache has even started.

ESSENTIAL POINTS

Migraine is a brain disorder involving both headache and altered sensory, limbic, and homeostatic processing. A complex interplay between neurotransmitter systems, physiologic systems, and pain processing likely occurs. Targeting various therapeutic substrates within these networks provides an exciting avenue for future migraine therapeutics.

Neurite Damage in Patients with Migraine

We examined neurite orientation dispersion and density imaging in patients with migraine. We found that patients with medication overuse headache exhibited lower orientation dispersion than those without. Moreover, orientation dispersion in the body of the corpus callosum was statistically negatively correlated with migraine attack frequencies. These findings indicate that neurite dispersion is damaged in patients with chronic migraine. Our study results indicate the orientation preference of neurite damage in migraine.

Visual Snow Syndrome in Patient with Migraine: Case Report and Literature Review

Visual snow syndrome (VSS) is a rarely diagnosed neurological phenomenon. It is a visual disorder characterised by the presence of numerous white, black, or translucent dots in the visual field, resembling the 'snow' of an analogue TV set experiencing reception interference. According to The International Classification of Headache Disorders, 3rd edition, visual snow is defined as a pattern of continuous small dots across the visual field lasting >3 months and accompanied by at least two of the following four additional symptoms: palinopsia, increased entoptic phenomena, photophobia, and nyctalopia. These complaints are not consistent with a typical migraine with visual aura and cannot be better explained by another disorder. The authors present the case of a 39-year-old woman who was diagnosed with VSS. The symptoms appeared after a migraine attack and had not alleviated. The patient reported a sensation of constant 'TV screen snow'. A neurological examination found no signs of focal damage to the nervous system. The results of the ophthalmological examination, MRI of the brain with contrast, MRI of the eye sockets, and EEG were normal. VSS is a phenomenon that is still not fully understood, different from migraine aura and associated with a number of additional symptoms. VSS is very difficult to treat. In this case, a lot of drugs were used without improvement. Further research must be conducted to determine the best treatment options for these patients.