Subsegmentation of the hippocampus in subgroups of migraine with aura patients: advanced structural neuroimaging study.

BACKGROUND: This study investigated for a possible contributing role of hippocampus in the different clinical phenotypic manifestations of migraine aura. METHODS: Herein, patients were categorized as those with pure visual aura (MwAv), those who reported additional somatosensory and dysphasic symptoms (MwAvsd), and healthy controls (HCs). Neuroimaging data obtained using FreeSurfer-based segmentation of hippocampal subfields were compared between HCs and patients with migraine with aura, as well as between HCs and those with MwAv and MwAvsd. The average migraine aura complexity score (MACS) was calculated for each patient to investigate the correlation between hippocampal subfield volume and migraine aura complexity. RESULTS: Herein, 46 patients with migraine with aura (28 MwAvsd and 18 MwAv) and 31 HCs were included. There were no significant differences in the hippocampal subfields between HCs and patients with migraine with aura. The average MACS negatively correlated with the volumes of the left and right hippocampi, Cornu Ammonis (CA) 1, CA3, CA4, molecular layer, left granule cell layer of the dentate gyrus, hippocampal fissure, and hippocampus-amygdala transition area. The MwAvsd subgroup had significantly smaller whole hippocampal volumes in both hemispheres, as well as in both subicula, compared with the MwAv subgroup and HCs. In addition, the left molecular layer, right CA1, and hippocampal fissures were significantly smaller in the MwAvsd group than in the MwAv subgroup and HCs. CONCLUSIONS: Smaller left and right hippocampal volumes, particularly of the subiculum/CA1 area, may play an important role in the pathophysiology of somatosensory and dysphasic symptoms in migraine with aura.

Normal glymphatic system function in patients with migraine: A pilot study.

OBJECTIVE: No studies have evaluated the glymphatic system function in patients with migraine. In this pilot study, we evaluated and compared the alterations in the glymphatic system function in patients with migraine with healthy controls using a diffusion tensor imaging (DTI) analysis along the perivascular space (DTI-ALPS) method. We also investigated the differences in the glymphatic system function table between patients with migraine with and without aura using the ALPS method. METHODS: This field study used a cross-sectional study design. We prospectively enrolled patients with migraine and healthy controls. All brain magnetic resonance imaging (MRI), including DTI, in participants, patients with migraine, and healthy controls were obtained using the same MRI scanner. We calculated and compared the ALPS index between patients with migraine and healthy controls, and between patients with migraine with and without aura. In addition, we investigated the association between the glymphatic system function and the clinical characteristics of migraine. RESULTS: We enrolled 92 patients with migraine and 80 healthy controls. There were no significant differences in the ALPS index between patients with migraine and healthy controls (1.655 ± 0.335 [patients with migraine] vs. 1.713 ± 0.297 [controls], difference = 0.058, 95% confidence interval [CI] of difference = -0.037 to 0.154, p = 0.233), and between patients with migraine with and without aura (1.690 ± 0.380 [with aura] vs. 1.645 ± 0.323 [without aura], difference = -0.044, 95% CI of difference = -0.213 to 0.124, p = 0.601). There was no significant correlation between the ALPS index and clinical characteristics of migraine, including age (r = -0.07, p = 0.507), age at onset (r = 0.07, p = 0.552), disease duration (r = -0.12, p = 0.306), attack frequency (r = -0.05, p = 0.668), and headache intensity (r = 0.00, p = 0.976). CONCLUSIONS: There was no glymphatic system dysfunction in patients with migraine. Moreover, there were no differences in the glymphatic system function between patients with migraine with and without aura. We also demonstrated the feasibility of the ALPS method, which can be used for research on various neurological diseases. Further studies are needed to confirm our findings.

Serial magnetic resonance imaging findings during severe attacks of familial hemiplegic migraine type 2: a case report.

BACKGROUND: Hemiplegic migraines represent a heterogeneous disorder with various presentations. Hemiplegic migraines are classified as sporadic or familial based on the presence of family history, but both subtypes have an underlying genetic etiology. Mutations in the ATP1A2 gene are responsible for Familial Hemiplegic type 2 (FHM2) or the sporadic hemiplegic migraine (SHM) counterpart if there is no family history of the disorder. Manifestations include migraine with aura and hemiparesis along with a variety of other symptoms likely dependent upon the specific mutation(s) present. CASE PRESENTATION: We report the case of an adult man who presented with headache, aphasia, and right-sided weakness. Workup for stroke and various infectious agents was unremarkable during the patient's extended hospital stay. We emphasize the changes in the Magnetic Resonance Imaging (MRI) over time and the delay from onset of symptoms to MRI changes in Isotropic Diffusion Map (commonly referred to as Diffusion Weighted Imaging (DWI)) as well as Apparent Diffusion Coefficient (ADC). CONCLUSIONS: We provide a brief review of imaging findings correlated with signs/symptoms and specific mutations in the ATP1A2 gene reported in the literature. Description of the various mutations and consequential presentations may assist neurologists in identifying cases of Hemiplegic Migraine, which may include transient changes in ADC and DWI imaging throughout the course of an attack.

Higher burden of rare frameshift indels in genes related to synaptic transmission separate familial hemiplegic migraine from common types of migraine.

BACKGROUND: Familial hemiplegic migraine (FHM) is a rare form of migraine with aura that often has an autosomal dominant mode of inheritance. Rare mutations in the CACNA1A, ATP1A2 and SCN1A genes can all cause FHM revealing genetic heterogeneity in the disorder. Furthermore, only a small subset of the affected individuals has a causal mutation. We set out to investigate what differentiates patients with FHM with no mutation in any known FHM gene from patients with common types of migraine in both familial and sporadic cases. METHODS: 2558 male and female participants from a migraine cohort from the Danish Headache Center were included. 112 had FHM; 743 had familial migraine; and 1703 had sporadic migraine. Using a linear regression model, we analysed for over-representation of rare functional variants in FHM versus familial migraine and sporadic migraine. Post hoc analyses included pathway analysis and testing for tissue specificity. RESULTS: We found that patients with FHM have significantly more rare frameshift indels compared with patients with familial migraine and sporadic migraine. Pathway analysis revealed that the 'ligand-gated ion channel activity' and 'G protein-coupled receptor downstream signalling' pathways were significantly associated with mutated genes. We moreover found that the mutated genes showed tissue specificity towards nervous tissue and muscle tissue. CONCLUSION: We show that patients with FHM compared with patients with common types of migraine suffer from a higher load of rare frameshift indels in genes associated with synaptic signalling in the central nervous system and possibly in muscle tissue contributing to vascular dysfunction.

Reversible Lesion of the Corpus Callosum in a Patient With Migraine With Aura: A Case Study.

OBJECTIVE: To describe a patient with migraine with aura (MWA) who was found to have a reversible lesion of the corpus callosum. BACKGROUND: Reversible lesions of the splenium of the corpus callosum are well-described clinical-radiographic phenomena, which have been associated with a wide array of disease states, including epilepsy, demyelinating disease, infection, and metabolic derangements. There have been few case reports in the literature to date of these lesions associated with migraine headache. DESIGN/METHODS: A case report. RESULTS: A 41 year-old female with a history of migraine with visual aura presented with headache associated with left-sided sensorimotor deficits. Routine laboratory tests were within normal limits. An electroencephlogram was also normal. Magnetic resonance imaging (MRI) of the brain with and without contrast revealed areas of restricted diffusion in the splenium and the genu of the corpus callosum. The patient's symptoms resolved after 2 days. A follow-up MRI 2 days after the onset of symptoms revealed resolution of the callosal lesions. The patient was diagnosed clinically with migraine with prolonged aura. CONCLUSION: MWA may be associated with reversible lesions of the corpus callosum.

In vivo imaging reveals that pregabalin inhibits cortical spreading depression and propagation to subcortical brain structures.

Migraine is characterized by severe headaches that can be preceded by an aura likely caused by cortical spreading depression (SD). The antiepileptic pregabalin (Lyrica) shows clinical promise for migraine therapy, although its efficacy and mechanism of action are unclear. As detected by diffusion-weighted MRI (DW-MRI) in wild-type (WT) mice, the acute systemic administration of pregabalin increased the threshold for SD initiation in vivo. In familial hemiplegic migraine type 1 mutant mice expressing human mutations (R192Q and S218L) in the CaV2.1 (P/Q-type) calcium channel subunit, pregabalin slowed the speed of SD propagation in vivo. Acute systemic administration of pregabalin in vivo also selectively prevented the migration of SD into subcortical striatal and hippocampal regions in the R192Q strain that exhibits a milder phenotype and gain of CaV2.1 channel function. At the cellular level, pregabalin inhibited glutamatergic synaptic transmission differentially in WT, R192Q, and S218L mice. The study describes a DW-MRI analysis method for tracking the progression of SD and provides support and a mechanism of action for pregabalin as a possible effective therapy in the treatment of migraine.

Impact of right-to-left shunt and transcatheter closure on the clinical features of migraine.

Objectives: In this study, we aimed to explore the influence of right-to-left shunt (RLS) presence on the clinical features of migraine and to follow-up on the post-operative curative effect of transcatheter patent foramen ovale (PFO) closure on migraine features.Methods: A total of 103 migraine patients were divided into a mild volume RLS group, moderate volume RLS group, large volume RLS group and non-RLS group in accordance with contrast enhancement transcranial Doppler (c-TCD) findings. The Visual Analogue Scale (VAS) score, migraine frequency, migraine duration, migraine disability assessment (MIDAS) and headache impact test-6 (HIT-6) scores were compared amongst the different groups. A total of 39 patients with moderate or large RLS received transcatheter PFO closure and those patients were followed up by the same criteria.Results: The attack frequency, HIT-6 and MIDAS scores amongst the migraine patients with moderate or large RLS were significantly higher than those in patients from the mild RLS group and non-RLS group (p < .05). The transcatheter closure was successful in all patients (n = 39), and no post-operative complications were observed during the hospitalisation and follow-up period. The differences in VAS, HIT-6 and MIDAS scores as well as the headache duration were statistically significant amongst patients before and after PFO closure (p < .05).Conclusions: Moderate to large RLS significantly influenced the clinical features of migraine, and transcatheter PFO closure could significantly relieve headache symptoms in migraine patients with PFO.

Neuronal injuries evidenced by transient cortical magnetic resonance enhancement in hemiplegic migraine: A case report.

BACKGROUND: Magnetic resonance imaging abnormalities in hemiplegic migraine have been described previously but were limited to a cortical thickening and biphasic alternation of hypoperfusion and hyperperfusion. Our report reveals possible blood-brain barrier disruption during migraine. CASE: We present the first demonstrated case of regressive diffuse hemispheric cortical enhancement in sporadic hemiplegic migraine, with histological correlation revealing neuronal lesions similar to ischemic lesions. This is probably due to the severity of the attack as indicated by the left hemiplegia and transient altered consciousness in our 43-year-old male patient. CONCLUSION: Cortical contrast enhancement on 3D T1 images may suggest migraine severity and be predictive of neuronal loss.

Proposal for a Migraine Aura Complexity Score.

OBJECTIVES: Currently, there is no scoring system for assessing the complexity of migraine aura. Our goal was to develop a Migraine Aura Complexity Score that synthesizes the quantity and quality of aura symptoms and to test its applicability in neuroimaging studies. METHODS: Patients with migraine aura were interviewed in order to obtain characteristics of migraine aura. Explorative and confirmatory analyses were used to develop the Migraine Aura Complexity Score. Median values were derived from 10 consecutive migraine auras in each patient. The Migraine Aura Complexity Score was correlated with an average cortical thickness of different brain areas in studied patients. The Surface-based Morphometric Analysis approach was used to estimate cortical thickness. RESULTS: This study included 23 (16 females and seven males) migraineurs with aura. Confirmatory factor analysis suggested the second-order model with three-factor measurement for grading migraine aura. The first factor is linked to higher cortical dysfunction during migraine aura, while the second is associated with the degree of involvement of primary visual and somatosensory cortices; the third linked symptoms of somatosensory aura and hand and head involvement. Positive correlation of Migraine Aura Complexity Score and averaged cortical thickness were found in the left and right hemispheres overall (r = 0.568, p = 0.007; r = 0.617, p = 0.003) and in some of their regions. CONCLUSIONS: This study demonstrates that the Migraine Aura Complexity Score could be a valuable tool for assessing migraine aura. The score could be used in neuroradiological studies in order to achieve a stratification of patients with migraine aura.

Recent Insights in Migraine With Aura: A Narrative Review of Advanced Neuroimaging.

INTRODUCTION: Migraine is a complex neurological disorder characterized by severe headaches associated with a plethora of sensory hypersensitivity and neurovegetative symptoms. In about one-third of the cases, a set of fully reversible focal neurological symptoms, the aura, accompanies the headache. In the last decades, advanced neuroimaging investigations allowed identification of structural, microstructural, and functional abnormalities characterizing the brain of patients with migraine with aura (MwA). However, mechanisms underlying the aura phenomena are still a matter of debate. AIMS: This article reviews the most significant findings from advanced neuroimaging studies in patients with MwA both to provide a unifying physiopathological model of the aura phenomena and to clarify the potential impact of advanced neuroimaging investigation in the clinical field. METHODS: A comprehensive review of PubMed citations was conducted by entering the key words "magnetic resonance imaging" combined with "migraine" AND "aura." Other key words included "grey matter" OR "white matter," "structural" OR "functional." The only restriction was to English-language publications. The abstracts of all articles published between 1997 and 2018 meeting these criteria were reviewed, and the full texts were examined for relevance to the topic. CONCLUSION: Although several advanced neuroimaging studies have been conducted to investigate the neural correlates of aura phenomena, they have failed in identifying underlying pathophysiological mechanisms in their entirety. Nevertheless, functional and structural neuroimaging findings concerning the extrastriate visual cortex are characterized by a high level of reproducibility, so much so that they could be applied, in a not so far future, as diagnostic, prognostic, or therapeutic biomarkers for MwA.

Migraine with visual aura associated with thicker visual cortex.

Until recent years it was believed that migraine with aura was a disorder causing intermittent neurological symptoms, with no impact on brain structure. However, recent MRI studies have reported increased cortical thickness of visual and somatosensory areas in patients with migraine with aura, suggesting that such structural alterations were either due to increased neuronal density in the areas involved, or a result of multiple episodes of cortical spreading depression as part of aura attacks. Subsequent studies have yielded conflicting results, possibly due to methodological reasons, e.g. small number of subjects. In this cross-sectional study, we recruited females aged 30-60 years from the nationwide Danish Twin Registry. Brain MRI of females with migraine with aura (patients), their co-twins, and unrelated migraine-free twins (controls) were performed at a single centre and assessed for cortical thickness in predefined cortical areas (V1, V2, V3A, MT, somatosensory cortex), blinded to headache diagnoses. The difference in cortical thickness between patients and controls adjusted for age, and other potential confounders was assessed. Comparisons of twin pairs discordant for migraine with aura were also performed. Comparisons were based on 166 patients, 30 co-twins, and 137 controls. Compared with controls, patients had a thicker cortex in areas V2 [adjusted mean difference 0.032 mm (95% confidence interval 0.003 to 0.061), V3A [adjusted mean difference 0.037 mm (95% confidence interval 0.008 to 0.067)], while differences in the remaining areas examined were not statistically significant [adjusted mean difference (95% confidence interval): V1 0.022 (-0.007 to 0.052); MT: 0.018 (-0.011 to 0.047); somatosensory cortex: 0.020 (-0.009 to 0.049)]. We found no association between the regions of interest and active migraine, or number of lifetime aura attacks. Migraine with aura discordant twin pairs (n = 30) only differed in mean thickness of V2 (0.039 mm, 95% CI 0.005 to 0.074). In conclusion, females with migraine with aura have a thicker cortex corresponding to visual areas and our results indicate this may be an inherent trait rather than a result of repeated aura attacks.

Ten years of follow-up in a large family with familial hemiplegic migraine type 1: Clinical course and implications for treatment.

Background Familial hemiplegic migraine (FHM) is a rare, genetic form of migraine with aura. The severity of the aura imposes an effective prophylaxis that is currently based on standard anti-migraine drugs. To this concern, only short-term reports are currently available. Methods Eight patients from a multigenerational FHM type 1 family harbouring a T666M mutation in the CACNA1A gene were referred to our ataxia outpatient clinic. Medical history, general and neurological examination as well as therapeutic approaches were recorded regularly on a routine basis for an average period of 13 years (range 9-15 years). Brain imaging studies and EEG data were also collected. Results Our long-term follow-up revealed that ictal manifestations, which usually improve after the adolescence, may reoccur later in the adulthood. Permanent neurological signs as assessed by means of clinical evaluation as well as follow-up MRIs, EEGs and neuropsychological testing remained stable. Interval therapy with non-selective calcium antagonists reduced the burden of migraine attacks and was well tolerated in the long term.

Brain atrophy following hemiplegic migraine attacks.

Background Patients with hemiplegic migraine (HM) may sometimes develop progressive neurological deterioration of which the pathophysiology is unknown. Patient We report a 16-year clinical and neuroradiological follow-up of a patient carrying a de novo p.Ser218Leu CACNA1A HM mutation who had nine severe HM attacks associated with seizures and decreased consciousness between the ages of 3 and 12 years. Results Repeated ictal and postictal neuroimaging revealed cytotoxic oedema during severe HM attacks in the symptomatic hemisphere, which later showed atrophic changes. In addition, progressive cerebellar atrophy was observed. Brain atrophy halted after cessation of severe attacks, possibly due to prophylactic treatment with flunarizine and sodium valproate. Conclusion Severe HM attacks may result in brain atrophy and prophylactic treatment of these attacks might be needed in an early stage of disease to prevent permanent brain damage.

Increased intrinsic brain connectivity between pons and somatosensory cortex during attacks of migraine with aura.

The neurological disturbances of migraine aura are caused by transient cortical dysfunction due to waves of spreading depolarization that disrupt neuronal signaling. The effects of these cortical events on intrinsic brain connectivity during attacks of migraine aura have not previously been investigated. Studies of spontaneous migraine attacks are notoriously challenging due to their unpredictable nature and patient discomfort. We investigated 16 migraine patients with visual aura during attacks and in the attack-free state using resting state fMRI. We applied a hypothesis-driven seed-based approach focusing on cortical visual areas and areas involved in migraine pain, and a data-driven independent component analysis approach to detect changes in intrinsic brain signaling during attacks. In addition, we performed the analyses after mirroring the MRI data according to the side of perceived aura symptoms. We found a marked increase in connectivity during attacks between the left pons and the left primary somatosensory cortex including the head and face somatotopic areas (peak voxel: P = 0.0096, (x, y, z) = (-54, -32, 32), corresponding well with the majority of patients reporting right-sided pain. For aura-side normalized data, we found increased connectivity during attacks between visual area V5 and the lower middle frontal gyrus in the symptomatic hemisphere (peak voxel: P = 0.0194, (x, y, z) = (40, 40, 12). The present study provides evidence of altered intrinsic brain connectivity during attacks of migraine with aura, which may reflect consequences of cortical spreading depression, suggesting a link between aura and headache mechanisms. Hum Brain Mapp 38:2635-2642, 2017. © 2017 Wiley Periodicals, Inc.

Genetic studies of Polish migraine patients: screening for causative mutations in four migraine-associated genes.

BACKGROUND AND AIM: Migraine is the most common neurological disorder, affecting approximately 12 % of the adult population worldwide, caused by both environmental and genetic factors. Three causative genes have been identified in familial hemiplegic migraine (FHM) families: CACNA1A, ATP1A2, and SCNA1A. Recently, several mutations in KCNK18 have also been found as causative factors in migraine development. The aim of our study was to identify the genetic background of migraine in the Polish population. MATERIAL AND METHODS: Sixty patients with migraine without aura (MO) or with different types of migraine with aura (MA), including sporadic hemiplegic, familial hemiplegic, and probable familial hemiplegic, were screened for mutations in the four genes previously linked with different types of migraine (ATP1A2, CACNA1A, SCN1A, and KCNK18). RESULTS: Two missense mutations were found. One novel mutation in SCN1A, encoding α subunit of sodium channel, causing amino acid change M1500V localized to a region encoding inactivation loop between transmembrane domains III and IV of the channel, was detected in a female FHM patient. The M1500V mutation was absent in a group of 62 controls, as well as in the ExAC database. The second, already known missense mutation S231P in KCNK18 was found in a female MA patient. Additionally, a novel intronic polymorphism possibly affecting alternative splicing of SCN1A, at chr2:16685249, g.77659T>C, and c.4581+32A>G, located between exons 24 and 25, in a region encoding the inactivation loop of the sodium channel was found in a female MO patient. No mutations in ATP1A2 or CACNA1A were found in the study group. CONCLUSIONS: The presence of SCN1A mutations and absence of mutations in ATP1A2 or CACNA1A suggest that the Polish patients represent FHM type 3. On the other hand, the presence of KCNK18 mutation indicated another FHM subtype. It could be speculated that contrary to other European populations, the genetic basis of migraine in the Polish population involves mutations in genes not included in the study. Next-generation sequencing methods should be implemented to identify other migraine-associated variants.

Inefficient constitutive inhibition of P2X3 receptors by brain natriuretic peptide system contributes to sensitization of trigeminal sensory neurons in a genetic mouse model of familial hemiplegic migraine.

BACKGROUND: On trigeminal ganglion neurons, pain-sensing P2X3 receptors are constitutively inhibited by brain natriuretic peptide via its natriuretic peptide receptor-A. This inhibition is associated with increased P2X3 serine phosphorylation and receptor redistribution to non-lipid raft membrane compartments. The natriuretic peptide receptor-A antagonist anantin reverses these effects. We studied whether P2X3 inhibition is dysfunctional in a genetic familial hemiplegic migraine type-1 model produced by introduction of the human pathogenic R192Q missense mutation into the mouse CACNA1A gene (knock-in phenotype). This model faithfully replicates several properties of familial hemiplegic migraine type-1, with gain-of-function of CaV2.1 Ca(2+) channels, raised levels of the algogenic peptide calcitonin gene-related peptide, and enhanced activity of P2X3 receptors in trigeminal ganglia. RESULTS: In knock-in neurons, anantin did not affect P2X3 receptor activity, membrane distribution, or serine phosphorylation level, implying ineffective inhibition by the constitutive brain natriuretic peptide/natriuretic peptide receptor-A pathway. However, expression and functional properties of this pathway remained intact together with its ability to downregulate TRPV1 channels. Reversing the familial hemiplegic migraine type-1 phenotype with the CaV2.1-specific antagonist, ω-agatoxin IVA restored P2X3 activity to wild-type level and enabled the potentiating effects of anantin again. After blocking calcitonin gene-related peptide receptors, P2X3 receptors exhibited wild-type properties and were again potentiated by anantin. CONCLUSIONS: P2X3 receptors on mouse trigeminal ganglion neurons are subjected to contrasting modulation by inhibitory brain natriuretic peptide and facilitatory calcitonin gene-related peptide that both operate via complex intracellular signaling. In the familial hemiplegic migraine type-1 migraine model, the action of calcitonin gene-related peptide appears to prevail over brain natriuretic peptide, thus suggesting that peripheral inhibition of P2X3 receptors becomes insufficient and contributes to trigeminal pain sensitization.

Abnormal synaptic Ca(2+) homeostasis and morphology in cortical neurons of familial hemiplegic migraine type 1 mutant mice.

OBJECTIVE: Migraine is among the most common and debilitating neurological conditions. Familial hemiplegic migraine type 1 (FHM1), a monogenic migraine subtype, is caused by gain-of-function of voltage-gated CaV 2.1 calcium channels. FHM1 mice carry human pathogenic mutations in the α1A subunit of CaV 2.1 channels and are highly susceptible to cortical spreading depression (CSD), the electrophysiologic event underlying migraine aura. To date, however, the mechanism underlying increased CSD/migraine susceptibility remains unclear. METHODS: We employed in vivo multiphoton microscopy of the genetically encoded Ca(2+)-indicator yellow cameleon to investigate synaptic morphology and [Ca(2+)]i in FHM1 mice. To study CSD-induced cerebral oligemia, we used in vivo laser speckle flowmetry and multimodal imaging. With electrophysiologic recordings, we investigated the effect of the CaV 2.1 gating modifier tert-butyl dihydroquinone on CSD in vivo. RESULTS: FHM1 mutations elevate neuronal [Ca(2+)]i and alter synaptic morphology as a mechanism for enhanced CSD susceptibility that we were able to normalize with a CaV 2.1 gating modifier in hyperexcitable FHM1 mice. At the synaptic level, axonal boutons were larger, and dendritic spines were predominantly of the mushroom type, which both provide a structural correlate for enhanced neuronal excitability. Resting neuronal [Ca(2+)]i was elevated in FHM1, with loss of compartmentalization between synapses and neuronal shafts. The percentage of calcium-overloaded neurons was increased. Neuronal [Ca(2+)]i surge during CSD was faster and larger, and post-CSD oligemia and hemoglobin desaturation were more severe in FHM1 brains. INTERPRETATION: Our findings provide a mechanism for enhanced CSD susceptibility in hemiplegic migraine. Abnormal synaptic Ca(2+) homeostasis and morphology may contribute to chronic neurodegenerative changes as well as enhanced vulnerability to ischemia in migraineurs.

Do interictal microembolic signals play a role in higher cortical dysfunction during migraine aura?

INTRODUCTION: The aim of this study was to evaluate the prevalence and clinical impact of interictal microembolic signals (MES) in patients suffering from migraine with higher cortical dysfunction (HCD), such as language and memory impairment, during an aura. PATIENTS AND METHODS: This study was carried out on 34 migraineurs with language and memory impairment during aura (HCD group), 31 migraineurs with only visual or visual and somatosensory symptoms during aura (Control group I), and 34 healthy controls (Control group II). We used a Doppler instrument to detect microemboli. Demographic data, disease features and the detection of MES between these groups, as well as the predictors of HCD during the aura, were analyzed. RESULTS: The duration of aura was longer and the frequency of aura was higher among patients with language and memory impairment during aura compared to Control group I. MES was detected in 29.4% patients from the HCD group, which was significantly higher compared to 3.2% in Control group I and 5.9% in Control group II. Regarding the absence or presence of MES, demographic and aura features were not different in the HCD subgroups. A longer duration of aura, the presence of somatosensory symptoms during the aura and the presence of interictal MES were independent predictors of HCD during the aura. CONCLUSION: The present findings indicate that HCD and MES are related in patients with migraine with aura. Further research is needed to better understand the exact pathophysiological mechanism.

Choroidal thickness measurements in migraine patients during attack-free period.

To identify any structural differences in macular choroidal thickness in migraine patients and compare them with that of control subjects by using spectral domain optic coherence tomography (SD-OCT). In this prospective study, choroidal thicknesses of 32 migraine patients during migraine attack-free period and 32 age- and sex-matched healthy subjects were measured using SD-OCT. All patients underwent a complete ophthalmic examination before the measurements. The migraine patients were classified into the migraine with aura group or the migraine without aura group. Migraine severity was assessed by visual analog scale (VAS), migraine disability questionnaire (Migraine Disability Assessment Score (MIDAS), and Wong-Baker faces pain rating scale. Thirty eyes of 32 subjects (31 female and 1 male) in the migraine group and 32 eyes of 32 subjects (31 female and 1 male) in control group were evaluated. In the study group, 16 patients suffered migraine without aura (MWA) and 16 patients were diagnosed as migraine with aura (MA). The mean subfoveal choroidal thickness (SFCT) was 353.3 ± 66.5 µm in the control group versus 304.3 ± 72.9 µm and 276.1 ± 61.4 µm in MWA and MA groups, respectively. The difference in SFCT between the migraine patients and the controls was significant (p < 0.001). Additionally, a moderate correlation was found between SFCT and the VAS score and W baker score (r = 0.48, p = 0.008 and r = 0.43, p = 0.02, respectively). The choroidal thickness was found to decrease significantly not only in migraine patients with aura but also in those without aura during the attack-free period.

Nonfunctional NaV1.1 familial hemiplegic migraine mutant transformed into gain of function by partial rescue of folding defects.

Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura. Mutations causing FHM type 3 have been identified in SCN1A, the gene encoding the Nav1.1 Na(+) channel, which is also a major target of epileptogenic mutations and is particularly important for the excitability of GABAergic neurons. However, functional studies of NaV1.1 FHM mutations have generated controversial results. In particular, it has been shown that the NaV1.1-L1649Q mutant is nonfunctional when expressed in a human cell line because of impaired plasma membrane expression, similarly to NaV1.1 mutants that cause severe epilepsy, but we have observed gain-of-function effects for other NaV1.1 FHM mutants. Here we show that NaV1.1-L1649Q is nonfunctional because of folding defects that are rescuable by incubation at lower temperatures or coexpression of interacting proteins, and that a partial rescue is sufficient for inducing an overall gain of function because of the modifications in gating properties. Strikingly, when expressed in neurons, the mutant was partially rescued and was a constitutive gain of function. A computational model showed that 35% rescue can be sufficient for inducing gain of function. Interestingly, previously described folding-defective epileptogenic NaV1.1 mutants show loss of function also when rescued. Our results are consistent with gain of function as the functional effect of NaV1.1 FHM mutations and hyperexcitability of GABAergic neurons as the pathomechanism of FHM type 3.