Key Concepts of Migraine Postdrome: A Qualitative Study to Develop a Post-Migraine Questionnaire

Postdromal symptoms in migraine: a REFORM study

BACKGROUND

Migraine is a multiphasic neurovascular disorder, where headache can be succeeded by postdromal symptoms. However, there are limited research on postdromal symptoms. This study aimed to investigate the proportion of individuals with migraine from a tertiary care unit reporting postdromal symptoms in adherence with the ICHD-3 definition. We also aimed to examine how the means of enquiry might influence the estimated proportions. Additionally, we explored whether any clinical features might affect the likelihood of reporting postdromal symptoms. Finally, we assessed to what extend the postdromal symptoms might impact the disease burden.

METHODS

In a cross-sectional study, we enrolled adult participants diagnosed with migraine who were asked to report their postdromal symptoms (i.e., unprompted reporting). Subsequently, a 16-item list was used to further ascertain the occurrence of postdromal symptoms (i.e., prompted reporting). Clinical characteristics were obtained through a semi-structured interview. Moreover, electronic questionnaires were used to assess the disease burden, i.e., the Six-Item Headache Impact Test (HIT-6), Migraine Disability Assessment (MIDAS), and the World Health Organization Disability Assessment 2.0 (WHODAS 2.0).

RESULTS

Among 631 participants with migraine, a higher proportion experienced at least one postdromal symptom when prompted (n = 509 [80.7%]) compared with unprompted reporting (n = 421 [66.7%], P < 0.001). Furthermore, the total number of postdromal symptoms experienced was greater with prompted than unprompted reporting (medians 3 [IQR 1 - 6] versus 1 [IQR 0 - 2]; P < 0.001). Furthermore, the likelihood of reporting postdromal symptoms increased with the presence of premonitory symptoms and decreased with higher number of monthly migraine days. Weak correlations were identified between the number of postdromal symptoms reported and both HIT-6 (ρ = 0.14; P < 0.001) and WHODAS scores (ρ = 0.15; P < 0.001), whilst no correlation was observed with MIDAS score (ρ = 0.08; P = 0.054).

CONCLUSIONS

Postdromal symptoms are prevalent in individuals with migraine from a tertiary care unit. However, reported estimates warrant cautious interpretation as they depend on the means of enquiry, presence of premonitory symptoms, and frequency of monthly migraine days. Moreover, a weak correlation was identified between the number of postdromal symptoms and both HIT-6 and WHODAS scores, indicating only a marginal influence on the disease burden.

What proportion of people with migraine report postdromal symptoms? A systematic review and meta-analysis of observational studies

BACKGROUND

Postdromal symptoms, following headache resolution, are said to constitute a distinct phase of the migraine attack. We question the evidence for this, with regard both to the nature of such symptoms and to how often they are reported to occur.

METHODS

We searched the Pubmed and Embase databases for relevant articles from their inception until 25 May 2023. We included observational studies recording the proportions of participants with migraine reporting one or more postdromal symptoms or specific individual symptoms. Two reviewers independently screened studies for relevance (agreeing on those to be included), extracted data and assessed risk of bias. Data were analyzed using random-effects meta-analysis to establish the proportions of those with migraine reporting one or more postdromal symptoms, whether among the general population or patients in clinic-based samples.

RESULTS

Large majorities of participants in either case reported postdromal symptoms: 97% in the only population-based study, and a mean of 86% (95% CI: 71-94%) in four clinic-based studies. The most commonly reported specific symptoms were fatigue (52%; 95% CI: 44-60%), concentration difficulties (35%; 95% CI: 14-65%) and mood changes (29%; 95% CI: 9-64%), none of these being clearly described. These estimates could not be considered reliable: they were subject to substantial study heterogeneity, none of the studies applied International Classification of Headache Disorders definitions of postdromal symptoms, and all had high risk of bias.

CONCLUSION

Postdromal symptoms in migraine appear to be very commonly reported, but the data are unreliable with regard both to their nature and to how often they occur. Further studies are needed to conclude that they constitute a distinct phase of migraine.

Visual respiratory biofeedback to improve visuospatial cognition and cardiac interoception in migraineurs: a study protocol for a randomized controlled trial

Objectives

Migraine is a complex neurological disorder that typically presents with unilateral cephalgia associated with cognitive impairment and reduced interoception. These symptoms result in socio-economic repercussions due to reduced productivity, efficiency, and work performance. Therefore, along with headache management, improving cognition and interoception should also be significant therapeutic targets to effectively manage migraine. To achieve this, we propose to explore the role of a yoga-based visual respiratory biofeedback (VRB) as a possible therapeutic strategy.

Methods and analysis

At least 64 participants will be recruited for the trial after screening for eligibility criteria, using the migraine screening questionnaire and Montreal cognitive assessment test. They will be randomly allocated (1:1) to either the experimental group receiving a 20-min session of yoga-based VRB or the control group who will be asked to watch a documentary film for the same duration. Visuospatial cognition will be assessed by the Corsi block-tapping task, and cardiac interoceptive accuracy will be assessed by the heartbeat counting task at baseline and immediately after the intervention. Based on the distribution and variance of the data obtained, analysis will be conducted based on linear mixed models using SPSS version 28.0.1.0, with a two-sided p-value of < 0.05 considered to be statistically significant.

Discussion

To the best of our knowledge, this is the first study to design and assess the effects of yoga-based biofeedback therapy on cognition and cardiac interoception in migraineurs. Furthermore, we postulated that pranayama's therapeutic effects might be enhanced by using visual yogic respiratory biofeedback. Considering the socio-economic burden of migraine, if found effective, VRB investigated in the trial could be considered as a therapeutic strategy.

Clinical trial registration

ClinicalTrials.gov CTRI, CTRI/2023/03/050430.

The not so hidden impact of interictal burden in migraine: A narrative review

Migraine is a highly prevalent neurological disease of varying attack frequency. Headache attacks that are accompanied by a combination of impact on daily activities, photophobia and/or nausea are most commonly migraine. The headache phase of a migraine attack has attracted more research, assessment tools and treatment goals than any other feature, characteristic, or phase of migraine. However, the migraine attack may encompass up to 4 phases: the prodrome, aura, headache phase and postdrome. There is growing recognition that the burden of migraine, including symptoms associated with the headache phase of the attack, may persist between migraine attacks, sometimes referred to as the "interictal phase." These include allodynia, hypersensitivity, photophobia, phonophobia, osmophobia, visual/vestibular disturbances and motion sickness. Subtle interictal clinical manifestations and a patient's trepidation to make plans or commitments due to the unpredictability of migraine attacks may contribute to poorer quality of life. However, there are only a few tools available to assess the interictal burden. Herein, we examine the recent advances in the recognition, description, and assessment of the interictal burden of migraine. We also highlight the value in patients feeling comfortable discussing the symptoms and overall burden of migraine when discussing migraine treatment needs with their provider.

Migraine Pathophysiology in Children and Adolescents: A Review of the Literature

Although migraine in adult and pediatric patients are overall very similar to each other, differences in prevalence, presentation, and treatment efficacy may reflect slight differences in the pathophysiological processes underlying migraine in these patient groups, perhaps because of ongoing development of the nervous system during childhood and adolescence. Although major gains have been made in understanding the pathophysiology of migraine in adults in recent years, equivalent research on migraine in pediatric patients continues to lag behind. In this review, we will describe the current state of migraine research in pediatric patients with regard to presentation and frequency of prodromal and postdromal symptoms, ictal and interictal calcitonin gene-related peptide elevation, and evidence for cortical spreading depression, thus covering all phases of migraine, and discuss how the findings seen here may relate to possible underlying pathophysiological mechanisms of migraine. We aim to elucidate possible differences between migraine in children and adults, and the need for further research specific to pediatric patients with migraine in order to improve treatment in this patient group.

Migraine Is More Than Just Headache: Is the Link to Chronic Fatigue and Mood Disorders Simply Due to Shared Biological Systems?

Migraine is a symptomatically heterogeneous condition, of which headache is just one manifestation. Migraine is a disorder of altered sensory thresholding, with hypersensitivity among sufferers to sensory input. Advances in functional neuroimaging have highlighted that several brain areas are involved even prior to pain onset. Clinically, patients can experience symptoms hours to days prior to migraine pain, which can warn of impending headache. These symptoms can include mood and cognitive change, fatigue, and neck discomfort. Some epidemiological studies have suggested that migraine is associated in a bidirectional fashion with other disorders, such as mood disorders and chronic fatigue, as well as with other pain conditions such as fibromyalgia. This review will focus on the literature surrounding alterations in fatigue, mood, and cognition in particular, in association with migraine, and the suggested links to disorders such as chronic fatigue syndrome and depression. We hypothesize that migraine should be considered a neural disorder of brain function, in which alterations in aminergic networks integrating the limbic system with the sensory and homeostatic systems occur early and persist after headache resolution and perhaps interictally. The associations with some of these other disorders may allude to the inherent sensory sensitivity of the migraine brain and shared neurobiology and neurotransmitter systems rather than true co-morbidity.

Protracted hypomobility in the absence of trigeminal sensitization after cortical spreading depolarization: Relevance to migraine postdrome

Migraine sufferers often exhibit photophobia and physical hypoactivity in the postdrome and interictal periods, for which no effective therapy currently exists. Cortical spreading depolarization (CSD) is a neural phenomenon underlying migraine aura. We previously reported that CSD induced trigeminal sensitization, photophobia, and hypomobility at 24 h in mice. Here, we examined the effects of CSD induction on light sensitivity and physical activity in mice at 48 h and 72 h. Trigeminal sensitization was absent at both time points. CSD-subjected mice exhibited significantly less ambulatory time in both light (P = 0.0074, the Bonferroni test) and dark (P = 0.0354, the Bonferroni test) zones than sham-operated mice at 72 h. CSD-subjected mice also exhibited a significantly shorter ambulatory distance in the light zone at 72 h than sham-operated mice (P = 0.0151, the Bonferroni test). Neurotropin® is used for the management of chronic pain disorders, mainly in Asian countries. The CSD-induced reductions in ambulatory time and distance in the light zone at 72 h were reversed by Neurotropin® at 0.27 NU/kg. Our experimental model seems to recapitulate migraine-associated clinical features observed in the postdrome and interictal periods. Moreover, Neurotropin® may be effective in ameliorating postdromal/interictal hypoactivity, especially in a light environment.

The migraine postdrome: Spontaneous and triggered phenotypes

Background

Non-painful symptoms in migraine following headache resolution can last up to days. Studying the postdrome is important to appreciate the morbidity associated with migraine.

Methods

Fifty-three subjects (n = 53) with migraine were studied in an experimental setting, collecting historical phenotypic information on the postdrome in their spontaneous attacks, and also associated with nitroglycerin-triggered attacks, while being observed prospectively. In a separate headache clinic-based cohort of migraineurs (n = 42), who were age and sex-matched to the experimental group, the same phenotypic data were extracted from their clinic records. Spontaneous and nitroglycerin-triggered attack phenotypes, and experimental and clinical cohort phenotypes were compared using agreement analysis.

Results

In the experimental group, 100% had a postdrome with their triggered attack, while 98% reported a postdrome in their spontaneous attacks. In the clinical group, 79% had reported a postdrome. In the experimental group, there was good agreement between spontaneous and nitroglycerin-triggered tiredness, hunger, mood change, sensory sensitivities and vertigo and with similarity in premonitory and postdrome phenotypes experienced in the same individual.

Conclusions

The migraine postdrome is common and symptomatically similar to the premonitory phase. The nitroglycerin model and migraine abortive agents can be used to study the postdrome experimentally. Systematic questioning of symptoms, as well as collateral histories from direct observers of migraine attacks, are likely to enhance symptomatic capture of the migraine postdrome, and aid understanding of attack mediation, abortion and neurobiology.

Pediatric vs. Adult Prodrome and Postdrome: A Window on Migraine Pathophysiology?

Few studies have been conducted on the prodromal and postdromal phases of the migraine attack in children and adolescents. Using a questionnaire, we found that 67% of 103 children and adolescents with migraine reported at least one prodromal symptom, with a mean number per subject of 1.8 (median 2.2). The most frequently reported prodromal symptoms were face changes, fatigue and irritability. In pediatric patients selected as having prodrome, fatigue, mood change and neck stiffness were the most frequently reported prodromal symptoms. Using a different design, Laurell et al. found that 71% of 137 pediatric patients reported at least one prodromal symptom with a mean number per subject of 1.9 ± 2.0. Studying postdrome was fraught with unexpected difficulties as our preliminary research showed. Patients reported 2 groups of symptoms occurring during the resolution phase of the headache: symptoms whose onset was before headache cessation and were persisting after it, and symptoms whose onset was after headache cessation. We referred to the former as persistent symptoms and to the latter as true postdromes. Ninety-one per cent of patients reported persistent symptoms, with a mean of 6.0 and a median of 2, asthenia, pallor, cognitive difficulties, anorexia, somnolence, and nausea being the more frequently reported. True postdromes were reported by 82% of patients, with a mean of 2.6 and a median of 2, thirst, somnolence, visual disturbances, food craving, paraesthesias, and ocular pain being the most frequent reported. Interestingly, several prodromal and postdromal symptoms are also encountered during the aura classic and/or accompany the headache phase. Functional imaging in migraine has showed that the activations in areas such as hypothalamus or brainstem may begin before headache onset and/or persist after headache relief. Thus, one may wonder whether prodromal and postdromal symptoms may indicate the involvement of the limbic system, dopaminergic pathways, the hypothalamus and the brainstem. Differences between children, adolescents and adults might contribute to the understanding of migraine neurobiology.

The Migraine Postdrome

PURPOSE OF REVIEW

The migraine postdrome is the least studied and least understood phase of migraine. This article covers the salient features of the migraine postdrome and provides insight into the history, clinical symptoms, and future implications of this phase of migraine.

RECENT FINDINGS

Prospective electronic diary studies have shown that patients are left disabled with various nonheadache symptoms in the migraine postdrome, and 81% of patients report at least one nonheadache symptom in the postdrome. Hence, it is important to understand this phase better and ensure that more effective treatments become available in the future to lessen the morbidity associated with this phase. Functional imaging shows widespread reduction in brain-blood flow in the postdrome, which explains the multitudes of symptoms experienced by patients.

SUMMARY

The disability related to migraine is not exclusive to the headache phase but extends into the postdrome phase and is associated with several nonheadache symptoms that prolong the symptoms experienced by patients with migraine. Further research into the postdrome is crucial to improve our overall understanding of migraine mechanisms. This knowledge may also help to treat the concurrent nonheadache symptoms better in the future. Novel neuroimaging techniques provide a valuable noninvasive tool to push the frontiers in the understanding of migraine pathophysiology. These methods may help shed further light onto the possible links between key brain structures and networks that could be implicated in the pathophysiology of the various migraine phases.

The migraine postdrome

PURPOSE OF REVIEW

Migraine is a common, disabling neurological disorder that affects up to 12% of the world population. Its pathophysiology is incompletely described. Of the various phases of migraine, the migraine postdrome is the least studied and hence the least understood.

RECENT FINDINGS

Electronic diary studies show patients are left disabled with non-headache symptoms in the migraine postdrome. Hence, the importance of understanding the phase better and ensuring that more effective treatments become available in the future to cut down the morbidity associated with this phase.

SUMMARY

The disability related to migraine is not limited to the headache phase and pans out to include the postdrome phase. The migraine postdrome needs to be studied more as this may improve our overall understanding of migraine mechanisms and also treat the concurrent symptoms better.

Clinical description of attack-related cognitive symptoms in migraine: A systematic review

Introduction

Cognitive symptoms have been described during migraine attacks since the Roman era; while being neglected throughout the centuries, they are relevant contributors to migraine-related disability.

Objective

To determine whether cognitive symptoms are included in clinical series describing migraine attack phenomenology, and which symptoms occur in each attack phase.

Method

Systematic review of existing data on clinical descriptions of migraine attacks, focusing on cognitive symptomatology. Data were organized and analyzed qualitatively, due to methodological differences between studies.

Results

Twenty-four articles were reviewed, with a total sample of 7007 patients, including 82.9% females with an average age of 39.2 years. Twenty one (75%) studies analyzed one phase of the attack (eight prodromes, five auras, one between aura and pain, three headaches and three postdromes), the remaining studied more than one phase. Cognitive complaints were the most frequent symptom of the prodromic (30%) and headache (38%) phases, while fatigue (70%) dominated the resolution phase. Not enough data is available to estimate the frequency of cognitive symptoms during the aura.

Discussion

Cognitive symptoms are described in all phases of the migraine attack phenomenology in published clinical series of migraine. Their characteristics appear to be different in each attack phase, although methodological limitations prevent generalization of this finding.

Postdrome symptoms in pediatric migraine: A questionnaire retrospective study by phone in 100 patients

Background No study dedicated to postdrome symptoms of migraine attacks is available in children and adolescents. Objective To study the resolution phase of the migraine attack in children and adolescents. Methods 100 children and adolescents with ICHD-3 beta migraine without and/or with typical aura were included. Each patient, and one of her/his parents, were interviewed by phone about the postdrome phrase of their last six months' migraine attacks. They were specifically instructed to distinguish symptoms that had begun before and went on after migraine headache cessation (referred to as persistent symptoms), and symptoms whose onset was strictly after headache cessation (referred to as true postdromes). Results 91% of patients reported persistent symptoms, with a mean of 2.9 and a median of 2; asthenia, cognitive difficulties, pallor, cognitive slowing, anorexia, somnolence, and nausea were the most frequently reported. They lasted less than 12 h in 71% of patients. True postdromes were reported by 82% of patients, with a mean of 2.6 and a median of 2; thirst, somnolence, visual disturbances, food craving, paraesthesias, and ocular pain being the most frequently reported. They lasted less than 12 h in 94% of patients. Conclusions This study showed that children and adolescents with migraine had both frequent persistent symptoms and true postdromes. Both were notably different from those reported in adults.

The migraine postdrome: An electronic diary study

Objective:

To report migraine postdrome symptoms in patients who report nonheadache symptoms as part of their attacks.

Methods:

A prospective daily electronic diary study was conducted over 3 months in 120 patients with migraine. Nonheadache symptoms before, during, and after headache were collected on a daily basis. Visual analogue scales were used to capture the overall level of functioning and the severity of the headache. The postdrome was defined as the time from resolution of troublesome headache to return to normal.

Results:

Of 120 evaluable patients, 97 (81%) reported at least one nonheadache symptom in the postdrome. Postdrome symptoms, in order of frequency, included feeling tired/weary and having difficulty concentrating and stiff neck. Many patients also reported a mild residual head discomfort. In most attacks (93%), there was return to normal within 24 hours after spontaneous pain resolved. There was no relationship between medication taken for the headache and the duration of the postdrome. The severity of the migraine was not associated with the duration of the postdrome. Overall state of health scores remained low during the postdrome.

Conclusion:

Nonheadache symptoms in the postdrome were common and may contribute to the distress and disability in the patients studied. Postdrome symptoms merit larger observational studies and careful recording in clinical trials of acute and preventive migraine treatments.

The impact of cognitive symptoms on migraine attack-related disability

Background

The socio-economic impact of migraine is mostly related to work loss either by absenteeism or decreased work performance. Migraine-associated cognitive dysfunction during an attack may contribute to these difficulties.

Objective

The objective of this article is to analyze the presence and relevance of cognitive symptoms during migraine attacks and to relate their intensity and symptom-related disability with other migraine-defining symptoms.

Methods

Consecutive migraine patients of a headache clinic completed diaries scoring each migraine symptom (including cognitive symptoms) intensity and symptom-related disability.

Results

Of 100 consecutive patients included in this study, 34 (all females, age average 31.8 ± 8.8 years) returned information on 229 attacks, on average 6.7 per participant. Every symptom’s intensity was always rated slightly higher than the disability it caused. Pain was the symptom scored with the highest intensity and disability, followed by cognitive symptoms (difficulty in thinking and worsening with mental effort) and photo- and phonophobia. Scoring was independent of any of the clinical variables. Attack intensity and disability scores correlated with intensity and disability from pain and from worsening with mental effort.

Conclusions

Attack-related cognitive symptoms are intense and disabling. Some attack-related cognitive symptoms correlate to intensity and disability subjectively attributed to the migraine attack. Cognitive performance should be addressed as a valuable secondary endpoint in trials of acute migraine treatment.

Migraine and psychiatric disorders co-morbidity explained by sinus hypoxic nitric oxide theory - a new hypothesis on the Sino rhinogenic theory

Migraine is an extremely common incapacitating neurovascular disorder and has co morbidity with many psychiatric illnesses which are caused by neurotransmitter imbalance, neurodegenerative changes and genetic predisposition. The sinus hypoxic nitric oxide theory presents, diffused paranasal sinus nitric oxide in the nasal mucosa has been hypothesized as the primary molecule that initiates migraine. Existence of such pathophysiology in human beings is termed as sinus hypoxic nitric oxide phenomena. According to this new hypothesis the sinorhinogenic trigeminal nerve impulse distribution of the central nervous system, is suggested to cause central neurotransmitter track dysfunction and cortical spreading depression with neurodegeneration that may relate to co morbidity. Moreover, avoidance of the excess sinorhinogenic central neuronal influence to the brain in early child hood and early intervention in the case of genetic susceptible history with psychiatric illnesses would help to prevent the progression or aggravation of psychiatric illnesses according to this hypothesis. This article explains a new pathophysiological initiation between central effects of sinorhinogenic nitric oxide phenomena and psychiatric disorders. It also provides an etiologically important neuro vascular impulse generating pathway to cause or aggravate psychiatric disorders. Therefore patients who are clinically suspected of having migraine headache and psychiatric disorders should receive a comprehensive sinorhinological examination and evaluation based on the sinus hypoxic nitric oxide phenomena.

Migraine: a brain state

PURPOSE OF REVIEW

Migraine has traditionally been categorized as a pain disorder, focusing on headache as its central feature. This narrow view does not account for the complex array of premonitory and postrdromal symptoms that occur in the hours before and after headache. This review outlines evidence that supports a broader view of migraine as a pathological brain state.

RECENT FINDINGS

Studies of the clinical features of a migraine attack, in combination with imaging and electrophysiological studies, provide evidence that migraine involves widespread changes in brain function and connectivity. These changes parallel those seen in other brain states such as sleep. Neurochemical mediators, including adenosine, and nonsynaptic signalling mechanisms involving astrocytes may play a role in the migraine state.

SUMMARY

Consideration of a migraine attack as a brain state provides an expanded framework for understanding all of its symptoms, and the underlying alterations in the activity of multiple brain networks. Mechanisms driving the transition to the migraine state may represent novel targets for acute and preventive therapies.

Dihydroergotamine: a review of formulation approaches for the acute treatment of migraine

Dihydroergotamine (DHE) was first used to treat migraine in 1945 and is currently included among migraine-specific treatments for moderate-severe migraine. DHE may be administered through several routes of delivery, with efficacy and tolerability varying among formulations. We review DHE formulation approaches for the acute treatment of migraine, reviewing pharmacokinetics/dynamics and comparing clinical response among various formulations. Pharmacokinetic properties vary among DHE formulations, with peak concentration occurring in 6 min with intravenous, 34 min with intramuscular, 56 min with intranasal, 12 min with oral inhalation and 75 min with oral administration. DHE is a potent agonist at serotonin 5-HT1B and 5-HT1D receptors. Adverse effects due to binding to select adrenergic and dopaminergic receptors are significantly less with orally inhaled than intravenous DHE when comparing therapeutically effective doses. Among parenteral formulations (including subcutaneous, intramuscular, intravenous and nasal spray), efficacy is superior with injectable dosing. Nasal spray DHE is generally more effective than placebo, but less effective than sumatriptan. Orally inhaled DHE is likewise more effective than placebo, but there are no head-to-head comparisons with triptans available for review. Adverse effects, particularly nausea, may limit use of parenteral DHE. Nausea is generally less frequent with non-injectable dosing.

The evolution of a migraine attack - a review of recent evidence

A migraine attack is an extraordinarily complex brain event that takes place over hours to days. This review focuses on recent human studies that shed light on the evolution of a migraine attack. It begins with a constellation of premonitory symptoms that are associated with activation of the hypothalamus and may involve the neurotransmitter dopamine. Even in the premonitory phase, patients experience sensitivity to sensory stimuli, indicating that central sensitization is a primary phenomenon. The migraine attack progresses to a phase that in some patients includes aura, which involves changes in cortical function, blood flow, and neurovascular coupling. The aura phase overlaps with the headache phase, which is associated with further changes in blood flow and function of the brainstem, thalamus, hypothalamus, and cortex. Serotonin receptors, nitric oxide, calcitonin gene-related peptide, pituitary adenylate cyclase-activating polypeptide, and prostanoids are demonstrated specific chemical mediators of migraine based on therapeutic and triggered migraine studies. A number of migraine symptoms persist beyond resolution of headache into a postdromal phase, accompanied by persistent blood flow changes in several brain regions. Although these phases of migraine have substantial temporal, neurochemical, and anatomical overlap, each represents an important window onto the pathophysiology of migraine as well as a target for therapeutic intervention. A comprehensive approach to migraine requires an understanding of the entire range of mechanisms and resultant symptoms that occur throughout the evolution of an attack.