Evidence for a shared genetic susceptibility to migraine and epilepsy

A cross-sectional, multicenter survey of the prevalence and influencing factors for migraine in epilepsy

OBJECTIVES

Epilepsy and migraine are common chronic neurological disease. Epidemiologic studies and shared pathophysiology and treatment suggest that these two diseases overlap. However, migraine is often underestimated among patients with epilepsy. This study aimed to evaluate the prevalence of migraine and identify the related influencing factors among adult patients with epilepsy.

METHODS

Adult patients with epilepsy were recruited at the outpatient epilepsy clinic of 13 tertiary hospitals in China from February to September 2022. ID Migraine questionnaire was applied to evaluate for migraine. Both univariable and multivariable logistic regression models were used to explore the influencing factors of migraine.

RESULTS

A total of 1326 patients with epilepsy were enrolled in this study. The prevalence of migraine among patients with epilepsy was 19.2% (254/1326). In the multivariable analysis, being female (OR = 1.451, 95% CI: 1.068-1.975; p = 0.018), focal and focal to bilateral tonic-clonic seizures (OR = 1.583, 95% CI: 1.090-2.281; p = 0.015), and current seizure attack in the last 3 months (OR = 1.967, 95% CI: 1.282-3.063; p = 0.002) were the influencing factors for migraine. However, <10% of patients with epilepsy received analgesics for migraine.

SIGNIFICANCE

Approximately 20% of patients with epilepsy screened positive for migraine. Being female, focal and focal to bilateral tonic-clonic seizures, and current seizure attack in the last 3 months were the influencing factors for migraine. Neurologists should pay more attention to the screening and management of the migraine among patients with epilepsy in China.

PLAIN LANGUAGE SUMMARY

Epilepsy and migraine are common chronic neurological disease with shared pathophysiological mechanisms and therapeutic options. However, migraine is often underestimated among patients with epilepsy. This multicenter study aimed to evaluate the prevalence of migraine and current status of treatment. In this study, approximately 20% of patients with epilepsy screened positive for migraine. Female, focal and focal to bilateral tonic-clonic seizures, and current seizure attack in the last 3 months were identified as independent influencing factors for migraine. Despite the high prevalence, the treatment for migraine was not optimistic, neurologists should pay more attention to the screening and management of migraine.

A comparison of comorbid headache between patients with temporal lobe epilepsy and juvenile myoclonic epilepsy

Headache is one of the most common symptoms of epilepsy comorbidities. However, the relationship between the epilepsy and headache still needs clarification. Previous studies mostly investigated the overall incidence and clinical features of the headache in patients with the epilepsy. Temporal lobe epilepsy (TLE) and juvenile myoclonic epilepsy (JME) are the common types of focal epilepsy and generalized epilepsy, respectively. Nevertheless, there was no study comparing the clinical features of headache between TLE and JME. This study aimed to analyze the headache features of these two types of epilepsy. Patients with either TLE or JME diagnosed with headache and referred to the West China Hospital of Sichuan University were consecutively recruited from June 2021 to June 2022. The duration of epilepsy was longer than 6 months in these patients. Data on headache and epilepsy were obtained through face-to-face questionnaires. The headache was classified according to the International Classification Headache Disorders-3rd edition (ICHD-III) criteria. χ2-test, t-test, rank-sum test, logistic regression modeling and Mann Whitney test were used to compare the clinical differences of the headache in TLE and JME. A total of 151 TLE patients and 30 JME patients were enrolled in this study. There was no significant difference in the family history of headache, epilepsy durations, headache types, proportion receiving analgesic therapy, the frequency of inter-ictal headache (inter-IH), and the quality of life in epilepsy -10 inventory (QOLIE-10) between the TLE and JME patients. Patients in the TLE group were significantly older (p = 0.004), and a lower percentage of them had a family history of epilepsy (p = 0.007) compared with the JME patients. The proportion of cases with refractory epilepsy was higher in the TLE group than that in the JME group (p < 0.001). The types of seizures in the TLE group varied from those in the JME group (p < 0.001). The composition of the antiseizure medications (ASM) applied in the TLE group differed from that in the JME group (p = 0.047), and the usage of oxcarbazepine was more frequently in the TLE group than in the JME group (p = 0.003). There was no difference in the headache types among patients with TLE or JME. Specifically, 67 (44.37%), 12 (7.95%), and 118 (7.95%) patients were found with inter-IH, pre-ictal headache (Pre-IH) and post-ictal headache (Post-IH) in the TLE group; while 8 (26.67%), 4 (13.33%) and 26 (86.67%) patients had inter-IH, Pre-IH and Post-IH in the JME group. Thirty-nine patients in the TLE group and 4 patients in the JME group were identified with more than one type of headaches, respectively. Tension-type headache (TTH) were found in 38 patients (25.17%) in the TLE group and 3 patients (10.00%) in the JME group, respectively; migraines were found in 10 patients (6.62%) in the TLE group and in 2 patients (6.67%) in the JME group. Patients in the TLE group had a higher headache-attributed lost time-90 days (HLT-90) score than those in the JME group (p = 0.019). The proportion of patients with inter-IH accompanied by nausea in the TLE group was higher than that in the JME group (p = 0.029), while the proportion of patients with frontal headache was lower than that in the JME group (p < 0.05). There was no significant difference in headache severity, quality, headache nature, unilateral/bilateral, and headache duration either in inter-IH or peri-ictal headache (Peri-IH) between the two groups. The logistic regression analysis suggested that except for HLT-90 (AUC = 0.622, p = 0.027), other factors were not found to be correlated with refractory epilepsy. The clinical features of headache differed between TLE and JME patients. TLE patients had a higher ratio of refractory epilepsy, more headache time loss compared with JME patients. HLT-90 was associated with the occurrence of refractory epilepsy in TLE patients. Taken together, we suggested that the comorbid headache may essentially be different between TLE and JME patients.

Neurological and psychiatric comorbidities of migraine: Concepts and future perspectives

BACKGROUND

This narrative review aims to discuss several common neurological and psychiatric disorders that show comorbidity with migraine. Not only can we gain pathophysiological insights by studying these disorders, comorbidities also have important implications for treating migraine patients in clinical practice.

METHODS

A literature search on PubMed and Embase was conducted with the keywords "comorbidity", "migraine disorders", "migraine with aura", "migraine without aura", "depression", "depressive disorders", "epilepsy", "stroke", "patent foramen ovale", "sleep wake disorders", "restless legs syndrome", "genetics", "therapeutics".

RESULTS

Several common neurological and psychiatric disorders show comorbidity with migraine. Major depression and migraine show bidirectional causality and have shared genetic factors. Dysregulation of both hypothalamic and thalamic pathways have been implicated as a possibly cause. The increased risk of ischaemic stroke in migraine likely involves spreading depolarizations. Epilepsy is not only bidirectionally related to migraine, but is also co-occurring in monogenic migraine syndromes. Neuronal hyperexcitability is an important overlapping mechanism between these conditions. Hypothalamic dysfunction is suggested as the underlying mechanism for comorbidity between sleep disorders and migraine and might explain altered circadian timing in migraine.

CONCLUSION

These comorbid conditions in migraine with distinct pathophysiological mechanisms have important implications for best treatment choices and may provide clues for future approaches.

Bioinformatics and network pharmacology analysis of drug targets and mechanisms related to the comorbidity of epilepsy and migraine

OBJECTIVE

The present study aimed to explore the mechanisms underlying the comorbidity of epilepsy and migraine, identify potential common targets for drug intervention, and provide insight into new avenues for disease prevention and treatment using an integrated bioinformatic and network pharmacology approach.

METHODS

Disease targets in epilepsy and migraine were screened using the DisGeNET database to identify intersecting gene targets. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEEG) enrichment analyses were then performed using the WebGestalt database. Furthermore, the STRING database was used to construct a protein-protein interaction (PPI) network, and Cytoscape software was used to analyze the protein molecular signals at the intersection of epilepsy and migraine. The Drugbank database was used to identify common targets for antiepileptic drugs in epilepsy and migraine to further analyze the disease-gene-target-drug interaction network. Finally, molecular docking simulations were performed to verify the hypothesis that migraine and epilepsy share common diseases and drug targets.

RESULTS

A total of 178 common targets for epilepsy and migraine were identified using the DisGeNET database, and the 24 genes most related to the diseases were screened using the Score_gda gene scoring system. GO enrichment analysis indicated that common targets were mainly enriched in biological processes and molecular functions, including membrane potential regulation, inorganic ion transmembrane transport, axonal signaling, and ion channel activity. KEGG pathway enrichment analysis indicated that the mechanism of action might be related to neuroactive ligand receptors, AGE-RAGE, cAMP, and VEGF signaling pathways. The PPI network construction and analysis results showed that the PPI grid had 23 central nodes and 24 connected edges, with an average node degree of 2.09 and an average clustering coefficient of 0.384. The 10 genes with potentially important roles in epilepsy and migraine were CACNA1A, KCNQ2, KCNA1, SCN1A, PRRT2, SCN8A, KCNQ3, SCN2A, GRIN2A, and GABRG2. Drugbank database results indicated that antiepileptic drugs, including lamotrigine, topiramate, valproic acid, carbamazepine, gabapentin, and perampanel, also had common targets with migraine. The three most important targets exhibited strong binding affinity with drugs in the molecular docking simulations.

CONCLUSION

Our systematic and comprehensive analyses of disease-gene-target-drug interaction networks identified several biological processes and molecular functions common to migraine and epilepsy, most of which were related to neuroactive ligand-receptor interactions. These data provide a new theoretical basis and reference for the clinical treatment of comorbid epilepsy and migraine and may aid in the development of novel pharmacological strategies.

Epilepsy and the gut: Perpetrator or victim?

The brain and the gut are linked together with a complex, bi-path link known as the gut-brain axis through the central and enteric nervous systems. So, the brain directly affects and controls the gut through various neurocrine and endocrine processes, and the gut impacts the brain via different mechanisms. Epilepsy is a central nervous system (CNS) disorder with abnormal brain activity, causing repeated seizures due to a transient excessive or synchronous alteration in the brain’s electrical activity. Due to the strong relationship between the enteric and the CNS, gastrointestinal dysfunction may increase the risk of epilepsy. Meanwhile, about 2.5% of patients with epilepsy were misdiagnosed as having gastrointestinal disorders, especially in children below the age of one year. Gut dysbiosis also has a significant role in epileptogenesis. Epilepsy, in turn, affects the gastrointestinal tract in different forms, such as abdominal aura, epilepsy with abdominal pain, and the adverse effects of medications on the gut and the gut microbiota. Epilepsy with abdominal pain, a type of temporal lobe epilepsy, is an uncommon cause of abdominal pain. Epilepsy also can present with postictal states with gastrointestinal manifestations such as postictal hypersalivation, hyperphagia, or compulsive water drinking. At the same time, antiseizure medications have many gastrointestinal side effects. On the other hand, some antiseizure medications may improve some gastrointestinal diseases. Many gut manipulations were used successfully to manage epilepsy. Prebiotics, probiotics, synbiotics, postbiotics, a ketogenic diet, fecal microbiota transplantation, and vagus nerve stimulation were used successfully to treat some patients with epilepsy. Other manipulations, such as omental transposition, still need more studies. This narrative review will discuss the different ways the gut and epilepsy affect each other.

Action Potentials Are Critical for the Propagation of Focally Elicited Spreading Depolarizations

Spreading depolarizations (SDs) of gray matter occur in the brain in different pathologic conditions, and cause varying degrees of tissue damage depending on the extent of metabolic burden on the tissue. As might be expected for such large depolarizations, neurons exhibit bursts of action potentials (APs) as the wave propagates. However, the specific role of APs in SD propagation is unclear. This is potentially consequential, since sodium channel modulation has not been considered as a therapeutic target for SD-associated disorders, because of ambiguous experimental evidence. Using whole-cell electrophysiology and single-photon imaging in acute cortical slices from male C57Bl6 mice, we tested the effects of AP blockade on SDs generated by two widely used induction paradigms. We found that AP blockade using tetrodotoxin (TTX) restricted propagation of focally induced SDs, and significantly reduced the amplitude of neuronal depolarization, as well as its Ca2+ load. TTX also abolished the suppression of spontaneous synaptic activity that is a hallmark of focally induced SD. In contrast, TTX did not affect the propagation of SD induced by global superfusion of high [K+]e containing artificial CSF (ACSF). Thus, we show that voltage-gated sodium channel (Nav)-mediated neuronal AP bursts are critical for the propagation and downstream effects of focally induced SD but are less important when the ionic balance of the extracellular space is already compromised. In doing so we corroborate the notion that two different SD induction paradigms, each relevant to different clinical situations, vary significantly in their characteristics and potentially their response to treatment.SIGNIFICANCE STATEMENT Our findings suggest that voltage-gated sodium channel (Nav) channels have a critical role in the propagation and downstream neural effects of focally induced spreading depolarization (SD). As SDs are likely induced focally in many disease conditions, these studies support sodium channel modulation, a previously underappreciated therapeutic option in SD-associated disorders, as a viable approach.

Headache in idiopathic/genetic epilepsies: Cluster analysis in a large cohort

OBJECTIVES

The link between headache and epilepsy is more prominent in patients with idiopathic/genetic epilepsy (I/GE). We aimed to investigate the prevalence of headache and to cluster patients with regard to their headache and epilepsy features.

METHODS

Patients aged 6-40 years, with a definite diagnosis of I/GE, were consecutively enrolled. The patients were interviewed using standardized epilepsy and headache questionnaires and their headache characteristics were investigated by experts in headache. Demographic and clinical variables were analyzed and patients were clustered according to their epilepsy and headache characteristics using an unsupervized K-means algorithm.

RESULTS

Among 809 patients, 508 (62.8%) reported having any type of headache; 87.4% had interictal headache and 41.2% had migraine. Cluster analysis revealed two distinct groups for both adults and children/adolescents. In adults, having a family history of headache, ≥5 headache attacks, duration of headache ≥24 months, headaches lasting ≥ 1 hour, and visual analog scale scores >5 were grouped in one cluster, and juvenile myoclonic epilepsy (JME), myoclonic, and generalized tonic-clonic seizures (GTCS) were clustered in this group (cluster 1). Self-limited epilepsy with centro-temporal spikes and epilepsy with GTCS alone were clustered in cluster 2 with the opposite characteristics. For children/adolescents, the same features as in adult cluster 1 were clustered in a separate group, except for the presence of JME syndrome and GTCS alone as a seizure type. Focal seizures were clustered in another group with the opposite characteristics. In the entire group, the model revealed an additional cluster, including patients with the syndrome of GTCS-alone (50.51%), with ≥ 5 attacks, headache lasting >4 hours, and throbbing headache; 65.66% of patients had a family history of headache in this third cluster (n=99).

SIGNIFICANCE

Patients with I/GE can be clustered into distinct groups according to headache features along with seizures. Our findings may help in management and planning for future studies.

NCOR2 is a novel candidate gene for migraine-epilepsy phenotype

HYPOTHESIS

To identify genetic factors predisposing to migraine-epilepsy phenotype utilizing a multi-generational family with known linkage to chr12q24.2-q24.3.

METHODS

We used single nucleotide polymorphism (SNP) genotyping and next-generation sequencing technologies to perform linkage, haplotype, and variant analyses in an extended Finnish migraine-epilepsy family (n = 120). In addition, we used a large genome-wide association study (GWAS) dataset of migraine and two biobank studies, UK Biobank and FinnGen, to test whether variants within the susceptibility region associate with migraine or epilepsy related phenotypes in a population setting.

RESULTS

The family showed the highest evidence of linkage (LOD 3.42) between rs7966411 and epilepsy. The haplotype shared among 12 out of 13 epilepsy patients in the family covers almost the entire NCOR2 and co-localizes with one of the risk loci of the recent GWAS on migraine. The haplotype harbors nine low-frequency variants with potential regulatory functions. Three of them, in addition to two common variants, show nominal associations with neurological disorders in either UK Biobank or FinnGen.

CONCLUSION

We provide several independent lines of evidence supporting association between migraine-epilepsy phenotype and NCOR2. Our study suggests that NCOR2 may have a role in both migraine and epilepsy and thus would provide evidence for shared pathophysiology underlying these two diseases.

Chronic Central Vestibulopathies for the Otolaryngologist

Central vestibulopathies involve disorders of the central nervous system that lead to problems with balance, often manifested as dizziness, vertigo, and gait difficulty. Central vestibulopathies can be distinguished from peripheral vestibulopathies with the use of certain tests, including nystagmography and posturography. The neuroanatomy of individuals with central vestibulopathies can reveal structural abnormalities in the posterior cerebrum or cerebellum. Various medications can be used to manage central vestibulopathies, including vestibular migraine.

Headache in people with epilepsy

Epidemiological estimates indicate that individuals with epilepsy are more likely to experience headaches, including migraine, than individuals without epilepsy. Headaches can be temporally unrelated to seizures, or can occur before, during or after an episode; seizures and migraine attacks are mostly not temporally linked. The pathophysiological links between headaches (including migraine) and epilepsy are complex and have not yet been fully elucidated. Correct diagnoses and appropriate treatment of headaches in individuals with epilepsy is essential, as headaches can contribute substantially to disease burden. Here, we review the insights that have been made into the associations between headache and epilepsy over the past 5 years, including information on the pathophysiological mechanisms and genetic variants that link the two disorders. We also discuss the current best practice for the management of headaches co-occurring with epilepsy and highlight future challenges for this area of research.

TRESK channel contributes to depolarization-induced shunting inhibition and modulates epileptic seizures

Glutamatergic and GABAergic synaptic transmission controls excitation and inhibition of postsynaptic neurons, whereas activity of ion channels modulates neuronal intrinsic excitability. However, it is unclear how excessive neuronal excitation affects intrinsic inhibition to regain homeostatic stability under physiological or pathophysiological conditions. Here, we report that a seizure-like sustained depolarization can induce short-term inhibition of hippocampal CA3 neurons via a mechanism of membrane shunting. This depolarization-induced shunting inhibition (DShI) mediates a non-synaptic, but neuronal intrinsic, short-term plasticity that is able to suppress action potential generation and postsynaptic responses by activated ionotropic receptors. We demonstrate that the TRESK channel significantly contributes to DShI. Disruption of DShI by genetic knockout of TRESK exacerbates the sensitivity and severity of epileptic seizures of mice, whereas overexpression of TRESK attenuates seizures. In summary, these results uncover a type of homeostatic intrinsic plasticity and its underlying mechanism. TRESK might represent a therapeutic target for antiepileptic drugs.

Decreased Resting-State Functional Connectivity of Periaqueductal Gray in Temporal Lobe Epilepsy Comorbid With Migraine

Objective: Patients with temporal lobe epilepsy (TLE) are at high risk for having a comorbid condition of migraine, and these two common diseases are proposed to have some shared pathophysiological mechanisms. Our recent study indicated the dysfunction of periaqueductal gray (PAG), a key pain-modulating structure, contributes to the development of pain hypersensitivity and epileptogenesis in epilepsy. This study is to investigate the functional connectivity of PAG network in epilepsy comorbid with migraine.

Methods: Thirty-two patients with TLE, including 16 epilepsy patients without migraine (EwoM) and 16 epilepsy patients with comorbid migraine (EwM), and 14 matched healthy controls (HCs) were recruited and underwent resting functional magnetic resonance imaging (fMRI) scans to measure the resting-state functional connectivity (RsFC) of PAG network. The frequency and severity of migraine attacks were assessed using the Migraine Disability Assessment Questionnaire (MIDAS) and Visual Analog Scale/Score (VAS). In animal experiments, FluoroGold (FG), a retrograde tracing agent, was injected into PPN and its fluorescence detected in vlPAG to trace the neuronal projection from vlPAG to PPN. FG traced neuron number was used to evaluate the neural transmission activity of vlPAG-PPN pathway. The data were processed and analyzed using DPARSF and SPSS17.0 software. Based on the RsFC finding, the excitatory transmission of PAG and the associated brain structure was studied via retrograde tracing in combination with immunohistochemical labeling of excitatory neurons.

Results: Compared to HCs group, the RsFC between PAG and the left pedunculopontine nucleus (PPN), between PAG and the corpus callosum (CC), was decreased both in EwoM and EwM group, while the RsFC between PAG and the right PPN was increased only in EwoM group but not in EwM group. Compared to EwoM group, the RsFC between PAG and the right PPN was decreased in EwM group. Furthermore, the RsFC between PAG and PPN was negatively correlated with the frequency and severity of migraine attacks. In animal study, a seizure stimulation induced excitatory transmission from PAG to PPN was decreased in rats with chronic epilepsy as compared to that in normal control rats.

Conclusion: The comorbidity of epilepsy and migraine is associated with the decreased RsFC between PAG and PPN.

Val66Met polymorphism is associated with decreased likelihood for pediatric headache and migraine

Background: Migraine is a complex multifactorial disorder and its pathogenesis still remains unclear. Evidence suggests the involvement of the activated trigeminovascular pathway, in which BDNF seems to play an important role. Therefore, BDNF polymorphisms are promising candidate susceptibility factors.Aim: BDNF rs6265 functional polymorphism was analyzed in order to determine its possible association with pediatric headache and migraine risk.Methods: The research included 120 consecutive pediatric patients who were diagnosed with headache and 120 healthy controls. The diagnosis was in compliance with the International Classification of Headache Disorders. Blood samples were collected from all participants and genotyped for rs6265.Results: BDNF rs6265 was significantly associated with decreased headache risk, particularly in the dominant model [Odds Ratio, OR (95% confidence interval, C.I.): 0.47 (0.26-0.85), p = 0.011] and the log-additive model [OR (95% C.I.): 0.48 (0.28-0.82), p = 0.0053]. During the sensitivity analysis, the associations were also maintained among patients with migraine.Conclusions: This is the first study to reveal a significant association of this BDNF variant with headache risk. Additionally, Val66Met was also for the first time related to decreased childhood migraine risk.

Decreased content of ascorbic acid (vitamin C) in the brain of knockout mouse models of Na+,K+-ATPase-related neurologic disorders

Na⁺,K⁺-ATPase is a crucial protein responsible for maintaining the electrochemical gradients across the cell membrane. The Na⁺,K⁺-ATPase is comprised of catalytic α, β, and γ subunits. In adult brains, the α3 subunit, encoded by ATP1A3, is predominantly expressed in neurons, whereas the α2 subunit, encoded by ATP1A2, is expressed in glial cells. In foetal brains, the α2 is expressed in neurons as well. Mutations in α subunits cause a variety of neurologic disorders. Notably, the onset of symptoms in ATP1A2- and ATP1A3-related neurologic disorders is usually triggered by physiological or psychological stressors. To gain insight into the distinct roles of the α2 and α3 subunits in the developing foetal brain, whose developmental dysfunction may be a predisposing factor of neurologic disorders, we compared the phenotypes of mouse foetuses with double homozygous knockout of Atp1a2 and Atp1a3 (α2α3-dKO) to those with single knockout. The brain haemorrhage phenotype of α2α3-dKO was similar to that of homozygous knockout of the gene encoding ascorbic acid (ASC or vitamin C) transporter, SVCT2. The α2α3-dKO brain showed significantly decreased level of ASC compared with the wild-type (WT) and single knockout. We found that the ASC content in the basal ganglia and cerebellum was significantly lower in the adult Atp1a3 heterozygous knockout mouse (α3-HT) than in the WT. Interestingly, we observed a significant decrease in the ASC level in the basal ganglia and cerebellum of α3-HT in the peripartum period, during which mice are under physiological stress. These observations indicate that the α2 and α3 subunits independently contribute to the ASC level in the foetal brain and that the α3 subunit contributes to ASC transport in the adult basal ganglia and cerebellum. We propose that decreases in ASC levels may affect neural network development and are linked to the pathophysiology of ATP1A2- and ATP1A3-related neurologic disorders.

Brain Network Integration in Patients with Migraine: A Magnetoencephalography Study

Migraine is a common disorder with high social and medical impact. Patients with migraine have a much higher chance of experiencing headache attacks compared with the general population. Recent neuroimaging studies have confirmed that pathophysiology in the brain is not only limited to the moment of the attack but is also present in between attacks, the interictal phase. In this study, we hypothesized that the topology of functional brain networks is also different in the interictal state, compared with people who are not affected by migraine. We also expected that the level of network disturbances scales with the number of years people have suffered from migraine. Functional connectivity between 78 cortical brain regions was estimated for source-level magnetoencephalography data by calculating the phase lag index, in five frequency bands (delta-beta), and compared between healthy controls (n = 24) and patients who had been suffering from migraine for longer than 6 years (n = 12) or shorter than 6 years (n = 12). Moreover, the topology of the functional networks was characterized using the minimum spanning tree. The migraine groups did not differ from each other in functional connectivity. However, the network topology was different compared with healthy controls. The results were frequency specific, and higher average nodal betweenness centrality was specifically evident in higher frequency bands in patients with longer disease duration, while an opposite trend was present for lower frequencies. This study shows that patients with migraine have a different network topology in the resting state compared with healthy controls, whereby specific brain areas have altered topological roles in a frequency-specific manner. Some alterations appear specifically in patients with long-term migraine, which might show the long-term effects of the disease.

The epidemiology of headaches among patients with epilepsy: a systematic review and meta-analysis

Background

Headache is the symptom of pain in the face, head or neck that causes disability in most people with medical and neurological disorders. It frequently co-occurs with most chronic diseases such as epilepsy and significantly impacts the quality of life. However, epidemiologic data from different studies showed different rates of prevalence. Therefore, we conducted this review to summarize the available epidemiologic evidence on the topic and formulate recommendations for future research and clinical practice.

Methods

We followed the preferred reporting items for systematic review and meta-analysis (PRISMA) guidelines. We systematically searched the literature using popular databases such as PubMed, EMBASE, Psych-INFO, and SCOPUS. We further scanned the reference lists of the eligible studies to supplement our electronic search. The Comprehensive Meta-Analysis software version 3.0 (CMA 3.0) was used to conduct a meta-analysis. Subgroup and sensitivity analysis were performed and Cochran’s Q- and the I²- test were used to assess the source of heterogeneity. The funnel plot and Egger’s regression tests were used to assess potential publication bias.

Results

A total of 17 studies conducted both in developed and developing countries including 5564 study participants were combined in this meta-analysis. The pooled estimated prevalence of headache among patients with epilepsy was 48.4%. The pooled estimated prevalence of Inter-Ictal headache (IIH) (42.2%) and Postictal headache (PIH) (43.1%) were higher when compared to tension-type headache (TTH) (26.2%), migraine with aura (26.0%) and migraine without aura (10.4%). The pooled prevalence of headache was 50.6% and 49.5% for developed and developing countries respectively. The pooled prevalence of headache among patients with epilepsy was considerably higher among females (63.0%) when compared to males (33.3%). Moreover, the pooled estimated prevalence of headache among patients with epilepsy was ranging from 46.0% to 52.2% in a leave-one-out sensitivity analysis.

Conclusion

The pooled estimated prevalence of headache among patients with epilepsy was considerably high (48.4%). Screening and appropriate management of headaches among patients with epilepsy are warranted.

Studies on the Mechanism of Glutamate Metabolism in NTG-Induced Migraine Rats Treated with DCXF

Objective

To explore the mechanism of the antimigraine effect by active components extracted from the Dachuanxiong prescription (DCXF), nitroglycerin- (NTG-) induced migraine rats were used to detect the change of glutamate metabolism and the overall metabolic profile at different time points in the serum and Trigeminocervical complex(TCC) samples.

Method

The biological samples that were obtained at 30 minutes, 60 minutes, and 90 minutes after model establishment or drug administration were tested by GC-TOF-MS. Then, real-time PCR and western blot were applied to detect changes in the expression of some substances involved in glutamate metabolism.

Result

DCXF could improve the metabolic profile of serum and TCC in migraine rats and showed the time trend of treatment, mainly involved by amino acid metabolism (glutamate, aspartic acid, and alanine metabolism). In addition, DCXF could increase the expressions of GS at 60 min and 90 min and EAAT1 at 90 min. The results of GS protein were similar to that of mRNA.

Conclusion

The antimigraine effect of DCXF could be achieved by improving the metabolic profile and increasing the expressions of GS and EAAT1 to promote the glutamate cycle of TCC and serum samples in NTG-induced migraine rats to a certain extent.

The comorbidity of headaches in pediatric epilepsy patients: How common and what types?

OBJECTIVE

To estimate the prevalence and characteristics of headache in pediatric epileptic patients.

METHODS

This cross-sectional study was performed over 6 months period from January 2018 to June 2018 at King Abdullah Specialist Children Hospital, King Abdulaziz Medical City, Riyadh, Kingdom of Saudi Arabia using a structured questionnaire in pediatric patients with epilepsy.

RESULTS

There were 142 patients enrolled (males, 57.7%; average age, 10.7+/-3.1 years) with idiopathic epilepsy (n=115, 81%) or symptomatic epilepsy (n=27, 19%). Additionally, patients had focal epilepsy (n=102, 72%) or generalized epilepsy (n=40, 28%), and among them, 11 had absence epilepsy. Overall, 65 (45.7%) patients had headaches compared with 3/153 (2%) in the control group (p<0.0001). Among the 65 patients with headaches, 29 (44.6%) had migraine-type, 12 (18.4%) had tension-type, and 24 (36.9%) had unclassified headache. There was no significant difference in age, gender, type of epilepsy syndrome, and antiepileptic used except in patients with or without headache. For migraine patients, there was a lower headache prevalence in the subgroup treated with valproic acid compared with other treatments.

CONCLUSION

Headache, predominantly migraine, is a common problem in pediatric epileptic patients and choosing valproic acid when possible can be important in preventing migraine in these patients.

Potential Protective Mechanisms of Ketone Bodies in Migraine Prevention

An increasing amount of evidence suggests that migraines are a response to a cerebral energy deficiency or oxidative stress levels that exceed antioxidant capacity. The ketogenic diet (KD), a diet mimicking fasting that leads to the elevation of ketone bodies (KBs), is a therapeutic intervention targeting cerebral metabolism that has recently shown great promise in the prevention of migraines. KBs are an alternative fuel source for the brain, and are thus likely able to circumvent some of the abnormalities in glucose metabolism and transport found in migraines. Recent research has shown that KBs-D-β-hydroxybutyrate in particular-are more than metabolites. As signalling molecules, they have the potential to positively influence other pathways commonly believed to be part of migraine pathophysiology, namely: mitochondrial functioning, oxidative stress, cerebral excitability, inflammation and the gut microbiome. This review will describe the mechanisms by which the presence of KBs, D-BHB in particular, could influence those migraine pathophysiological mechanisms. To this end, common abnormalities in migraines are summarised with a particular focus on clinical data, including phenotypic, biochemical, genetic and therapeutic studies. Experimental animal data will be discussed to elaborate on the potential therapeutic mechanisms of elevated KBs in migraine pathophysiology, with a particular focus on the actions of D-BHB. In complex diseases such as migraines, a therapy that can target multiple possible pathogenic pathways seems advantageous. Further research is needed to establish whether the absence/restriction of dietary carbohydrates, the presence of KBs, or both, are of primary importance for the migraine protective effects of the KD.

Clinical observation of the effect of prophylaxis on allodynia in patients with migraine

Objective

The clinical characteristics of migraine with and without allodynia were compared to evaluate the risk factors of cutaneous allodynia in migraine. The effects of prophylactic therapy on allodynia in patients with migraine were assessed based on the change in pain threshold after therapy.

Patients and methods

A total of 71 patients with migraine admitted to the Department of Neurology of Shandong Provincial Hospital were recruited in this study. The included patients were aged 18–70 years and did not present positive symptoms according to the nervous system examination. The variation in cutaneous allodynia was assessed for the role of classic prophylactic therapy in migraine-related allodynia, also termed as central sensitization (CS). Patients with migraine were randomized into two groups (topiramate and flunarizine groups), and the effect of drugs was evaluated by the change in cutaneous pain threshold between the two groups. Fifty-five patients were tested for pain threshold due to instrument failure. Pressure allodynia was measured with a force gage, and pricking was measured with Electronic von Frey Anesthesiometer. The pain threshold was measured every 3 months for 6 months. The variations in pain threshold after treatment were compared using t-test and χ² test.

Results

Allodynia was seen in 70.4% of the patients; of these, 76.3% were females. Female gender, duration of illness, and frequency of migraine attacks per month were significantly associated with allodynia. The rate of allodynia and frequency of headache declined significantly, the number of patients with allodynia was reduced, and the pain threshold improved dramatically after treatment. The composite adverse events were low after treatment with topiramate and flunarizine.

Conclusion

Allodynia was observed, especially in females who experienced frequent migraine attacks for a prolonged period. Gender, duration of illness, and number of migraine attacks per month were the major predictors of allodynia. Topiramate and flunarizine administered orally for a short duration can effectively improve the pain threshold and CS of patients with migraine, and efficiently relieve allodynia.

Relationship between right-to-left shunt and migraine in patients with epilepsy: a single-centre, cross-sectional study in China

OBJECTIVES

To investigate the relationship between right-to-left shunt and migraine to account for the unexplained high prevalence of migraine in patients with epilepsy.

DESIGN

This is a cross-sectional study. The diagnosis and interview process of patients with migraine was based on the International Classification of Headache Disorders-3 beta in patients with epilepsy. Participants underwent transthoracic echocardiography (TTE) with contrast medium to identify right-to-left shunt. The highest number of microbubbles were recorded in the left atrium before the complete microbubble outflow of the right atrium. A moderate-to-large shunt was defined as the presence of 10 or more microbubbles.

SETTING

A single-centre, cross-sectional study in China, 2015-2017.

PARTICIPANTS

Patients with epilepsy.

PRIMARY AND SECONDARY OUTCOME MEASURES

The primary outcome measures were the prevalence of migraine, the prevalence of right-to-left shunt in patients with migraine and those without migraine, and the prevalence of migraine in different degrees of shunting.

RESULTS

Three hundred thirty-nine participants with epilepsy who completed TTE were included in the analysis. The overall prevalence of migraine was 23.0%. One-third of the migraineurs had mild right-to-left shunt and one-fifth of the migraineurs had moderate-to-large right-to-left shunt. Patients with mild shunt did not have a higher prevalence of migraine than those without shunt (26.3% vs 18.1%, p=0.102); however, a higher prevalence of migraine was found in patients with moderate-to-large shunt (39.0% vs 18.1%, OR=2.90, 95% CI=1.41 to 5.98, p=0.003). Patients with migraine and patients without migraine had similar prevalence of mild shunt; however, patients with migraine had more moderate-to-large shunt (20.5% vs 9.6%, p=0.002). Right-to-left shunt and female were factors predicting migraine prevalence.

CONCLUSIONS

One-fifth of migraineurs were correlated with moderate-to-large right-to-left shunt which could be an underlying cause of migraine in epilepsy.

Epilepsy and migraine-Are they comorbidity?

Epilepsy and migraine often co-occur. From the clinical symptoms, they often have some signs of symptoms before onset; from the pathogenesis of epilepsy and migraine, both of them have a high degree of neuronal excitement and ion channel abnormalities; in terms of treatment, many antiepileptic drugs are work in migraine. All of this indicates that they interact with each other. But it is undeniable that there are interactions and relationships between them, and there are also some differences such as the different clinical episodes, the different ways of neuronal haperexcitability and the different drug treatment programs. And are they comorbidity? If we can better understand the correlation between seizures and migraines, then this will help develop better guidelines for clinical diagnosis and treatment.

Epilepsy

Epilepsy affects all age groups and is one of the most common and most disabling neurological disorders. The accurate diagnosis of seizures is essential as some patients will be misdiagnosed with epilepsy, whereas others will receive an incorrect diagnosis. Indeed, errors in diagnosis are common, and many patients fail to receive the correct treatment, which often has severe consequences. Although many patients have seizure control using a single medication, others require multiple medications, resective surgery, neuromodulation devices or dietary therapies. In addition, one-third of patients will continue to have uncontrolled seizures. Epilepsy can substantially impair quality of life owing to seizures, comorbid mood and psychiatric disorders, cognitive deficits and adverse effects of medications. In addition, seizures can be fatal owing to direct effects on autonomic and arousal functions or owing to indirect effects such as drowning and other accidents. Deciphering the pathophysiology of epilepsy has advanced the understanding of the cellular and molecular events initiated by pathogenetic insults that transform normal circuits into epileptic circuits (epileptogenesis) and the mechanisms that generate seizures (ictogenesis). The discovery of >500 genes associated with epilepsy has led to new animal models, more precise diagnoses and, in some cases, targeted therapies.

Shared mechanisms of epilepsy, migraine and affective disorders

Since the nineteenth century several clinical features have been observed in common between migraine and epilepsy (such as episodic attacks, triggering factors, presence of aura, frequent familiarity), but only in recent years researchers have really engaged in finding a common pathogenic mechanism. From studies of disease incidence, we understand how either migraine among patients with epilepsy or epilepsy among migraine patients are more frequent than in the general population. This association may result from a direct causality, by the same environmental risk factors and/or by a common genetic susceptibility. Ischemic events are the most frequent direct causes, especially among women and elderly people: migraine can lead to silent or clinically considerable strokes, and these ones could explain the increased risk of developing epilepsy in people with a history of migraine. Head injuries can lead headache, often with migraine characteristics, and seizures. But there are also many idiopathic cases. The comorbidity migraine-epilepsy might be explained in these cases by a neuronal hyperexcitability, which increases the risk of both diseases: a higher concentration of extracellular glutamate, the main excitatory neurotransmitter, leads in fact as a result a Cortical Spreading Depression (the pathophysiological mechanism at the base of aura) and convulsions; antiepileptic drugs such as topiramate are, therefore, used also in migraine prophylaxis. A genetic link between these two diseases is particularly evident in familial hemiplegic migraine: mutations of ATP1A2, SCN1A and CACNA1A genes, identified in this disease, have also been involved in different types of epilepsy and febrile seizures. The channelopathies, especially engaging sodium and potassium ions, can be the common pathogenic mechanism of migraine and epilepsy. Both migraine and epilepsy also have, compared to the general population, a higher prevalence and incidence of affective disorders such as anxiety, depression and suicidal ideation. Anxiety and depression can be part of symptoms that accompany migraine or seizures. Female patients with a long history of illness and frequent attacks are the most at risk. The impact of these diseases on the quality of life is the most obvious cause of these disorders, furthermore some antiepileptic drugs can have depressive effects on mood; the anxious-depressive disorders often result from the interaction between iatrogenic and psychosocial factor with common neurobiological pathogenesis. A chronic lowering of 5-HT (serotonin) levels has been demonstrated both in migraineurs and in depressed patients; amitriptyline and venlafaxine are the most indicated drugs in the treatment of migraine with comorbid depression currently. Likewise imbalance in dopamine levels has been also demonstrated: a D2 receptor genotype has been directly related to comorbidity migraine-depression. In women, hormonal fluctuations are also crucial, especially in the post-partum and late luteal phase, when the estrogenic reduction, associated with up-regulation of SNPs and down-regulation of serotonergic and GABAergic systems, increases the risk of migraine and depression. Furthermore, central sensitization phenomena have been highlighted in both diseases, and result in a progressive increase in the frequency of attacks up to chronicity and the consequent development of drug resistance and overuse. Further studies will be necessary to deepen the close relationship between these three diseases.

A systematic approach for identifying shared mechanisms in epilepsy and its comorbidities

Cross-sectional epidemiological studies have shown that the incidence of several nervous system diseases is more frequent in epilepsy patients than in the general population. Some comorbidities [e.g. Alzheimer's disease (AD) and Parkinson's disease] are also risk factors for the development of seizures; suggesting they may share pathophysiological mechanisms with epilepsy. A literature-based approach was used to identify gene overlap between epilepsy and its comorbidities as a proxy for a shared genetic basis for disease, or genetic pleiotropy, as a first effort to identify shared mechanisms. While the results identified neurological disorders as the group of diseases with the highest gene overlap, this analysis was insufficient for identifying putative common mechanisms shared across epilepsy and its comorbidities. This motivated the use of a dedicated literature mining and knowledge assembly approach in which a cause-and-effect model of epilepsy was captured with Biological Expression Language. After enriching the knowledge assembly with information surrounding epilepsy, its risk factors, its comorbidities, and anti-epileptic drugs, a novel comparative mechanism enrichment approach was used to propose several downstream effectors (including the GABA receptor, GABAergic pathways, etc.) that could explain the therapeutic effects carbamazepine in both the contexts of epilepsy and AD. We have made the Epilepsy Knowledge Assembly available at https://www.scai.fraunhofer.de/content/dam/scai/de/downloads/bioinformatik/epilepsy.bel and queryable through NeuroMMSig at http://neurommsig.scai.fraunhofer.de. The source code used for analysis and tutorials for reproduction are available on GitHub at https://github.com/cthoyt/epicom.

Pediatric Headache and Seizures

Headache and seizures are two of the most common complaints seen in the field of pediatric neurology with headache being number one. Both these conditions may coexist. Where the difficulty begins is when the symptoms are not clear cut in making a diagnosis, and conditions are possible as either an atypical seizure or migraine variant. What further complicates matters is the fact that there are many underlying neurologic conditions that carry with them a higher likelihood of developing both headaches and seizures, making each a distinct possibility when obtaining a history from a parent about unusual spells. Although differentiating between seizure and headache may not be easy, with a focused yet thorough history and appropriate use of investigative tools, it can be done. Coming to the correct diagnosis is only the start; once seizures and or headaches have been appropriately diagnosed then the real challenge begins and that is finding a way to successfully treat the headaches and seizures. Within pediatric neurology, the acute options tend to be more diagnosis specific whereas the prophylactic ones may overlap and treat both headaches and seizures. In the following review, we will discuss the epidemiology of pediatric headaches and seizures, the overlap between these 2 conditions in diagnosis, as well as how to tell them apart, and the treatment options and prognosis of both common neurologic disorders in children.

Epilepsy may cause increased pain sensitivity: Evidence from absence epileptic WAG/Rij rats

OBJECTIVE

The comorbidity of epilepsy and pain disorders as well as effectiveness of certain therapeutic approaches in both conditions attracted attention to epilepsy-pain interactions. This lead to the discovery of significantly shared pathophysiological mechanisms although many aspects remain largely unknown. To test the hypothesis that epilepsy may be associated with altered pain sensitivity, we analyzed interictal pain sensitivity using epilepsy prone WAG/Rij rats, a genetic model exhibiting age-related-onset absence epilepsy.

METHODS

Two series of experiments were conducted. In experiment I, pain sensitivity of symptomatic WAG/Rij rats were compared with age-matched control Wistar rats. In experiment II, pain sensitivity of WAG/Rij rats were monitored longitudinally when they were presymptomatic (at 2months) and symptomatic (after maturation, at 8months), and compared with age-matched control Wistar rats. Pain sensitivity was assessed by applying heat stimuli to hind paws and measuring the paw-withdrawal latency using thermal plantar analgesia meter in awake and freely moving animals. All pain measurements were made during the interictal period, confirmed by simultaneous electroencephalography through intracranially implanted electrodes.

RESULTS

In experiment I, the interictal pain withdrawal latency of symptomatic WAG/Rij rats was significantly shorter than control Wistar rats (P<0.01). In experiment II, WAG/Rij rats had significantly shorter latency of withdrawal response than control Wistar rats, both at presymptomatic (P<0.05) and symptomatic stage (P<0.0001). Matured (8months old) control Wistar rats demonstrated significantly increased withdrawal latency compared to the 2months animals (P<0.01), but the WAG/Rij rats did not (P>0.5).

CONCLUSION

Epileptic WAG/Rij rats present significantly increased pain sensitivity when compared to control Wistar rats, suggesting comorbidity of epilepsy and pain.

Headache and Epilepsy

Headache, especially migraine, has long been associated with epilepsy, based on the common clinical features of these disorders. Both migraine and epilepsy have a genetic predisposition and share common pathophysiological mechanisms including an imbalance between excitatory and inhibitory factors that result in spells of altered brain function and autonomic symptoms. There are well-documented reports on the headache as a sole manifestation of epileptic seizure and headache is commonly associated with as preictal, ictal, and postictal symptoms in epilepsy patients. In addition, migraine and epilepsy are frequently described as highly comorbid conditions and several antiepileptic drugs are used for the patients with migraine as well as epilepsy. In the present review, we briefly discuss the connection between headache and epilepsy in various aspects, including classification, clinical features, epidemiology, genetics, pathophysiology, and treatment.

Pediatric Epilepsy Surgery: The Prognostic Value of Central Nervous System Comorbidities in Patients and their Families

Central nervous system comorbidities have been identified in patients with epilepsy. Several of these comorbidities have been correlated with poor surgery outcomes in patient cohorts. The authors sought to determine if prevalence of comorbidities in pediatric epilepsy surgery patients and their families correlate with long-term seizure outcome in a cross-sectional analysis. Three-generation pedigrees were elicited to compare family history of epilepsy, ADHD, anxiety, autism, bipolar disorder, cognitive disability, depression, migraine, and motor disability to surgery outcomes in 52 patients. Proportions of affected patients and relatives were compared to general population comorbidity rates and the patients' most recent seizure outcome classification. Patients and families had significantly higher rates of comorbidities than the general population. Poorer long-term seizure outcomes following resective surgery were associated with autism or cognitive disability in patients. Together these data support evidence for a common pathophysiological mechanism between epilepsy and central nervous system comorbidities.

Genetics of Migraine: Insights into the Molecular Basis of Migraine Disorders

Migraine is a complex, debilitating neurovascular disorder, typically characterized by recurring, incapacitating attacks of severe headache often accompanied by nausea and neurological disturbances. It has a strong genetic basis demonstrated by rare migraine disorders caused by mutations in single genes (monogenic), as well as familial clustering of common migraine which is associated with polymorphisms in many genes (polygenic). Hemiplegic migraine is a dominantly inherited, severe form of migraine with associated motor weakness. Family studies have found that mutations in three different ion channels genes, CACNA1A, ATP1A2, and SCN1A can be causal. Functional studies of these mutations has shown that they can result in defective regulation of glutamatergic neurotransmission and the excitatory/inhibitory balance in the brain, which lowers the threshold for cortical spreading depression, a wave of cortical depolarization thought to be involved in headache initiation mechanisms. Other putative genes for monogenic migraine include KCKN18, PRRT2, and CSNK1D, which can also be involved with other disorders. There are a number of primarily vascular disorders caused by mutations in single genes, which are often accompanied by migraine symptoms. Mutations in NOTCH3 causes cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), a hereditary cerebrovascular disease that leads to ischemic strokes and dementia, but in which migraine is often present, sometimes long before the onset of other symptoms. Mutations in the TREX1 and COL4A1 also cause vascular disorders, but often feature migraine. With respect to common polygenic migraine, genome-wide association studies have now identified single nucleotide polymorphisms at 38 loci significantly associated with migraine risk. Functions assigned to the genes in proximity to these loci suggest that both neuronal and vascular pathways also contribute to the pathophysiology of common migraine. Further studies are required to fully understand these findings and translate them into treatment options for migraine patients.

The Clinical Implications of Todd Paralysis in Children With Benign Rolandic Epilepsy

The aim of this study was to describe the clinical and electroencephalographic (EEG) findings of postictal Todd paralysis in benign rolandic epilepsy of childhood and find out the possible correlation with migraine. Based on International Headache Society pediatric migraine criteria, patients were investigated for migraine, and 12 of the 108 patients with benign rolandic epilepsy (6 girls and 6 boys, 11.1%) were found to have postictal Todd paralysis. Ten of these 12 patients (83.3%) had pediatric migraine based on the diagnostic criteria. We showed comorbidity of migraine and benign rolandic epilepsy with postictal Todd paralysis in children. Increased incidence of migraine in the present study suggest that children who have benign rolandic epilepsy and postictal Todd paralysis are more likely to have migraines.

The Comorbidity of Migraine and Epilepsy in Children and Adolescents

Migraine and epilepsy share a number of clinical attributes, including pathophysiology and clinical expression. Both are paroxysmal in nature and thus constitute episodic disorders, yet either may be chronic and/or recurrent. Epileptic seizures and migraine headaches may be mistaken one for the other and may even overlap. In particular, occipital lobe seizures may be misdiagnosed as migraine auras. In this article, we review the relationship between migraine and epilepsy, including the known genetic contributions to both conditions, prodromal, ictal, and postictal headache and shared pathophysiology and treatment options. We describe clinical conditions in which both migraine and epilepsy are prominent features. Lastly, we discuss electronecephaographic abnormalities that have been known to occur in individuals with migraine.

Patients with psychogenic nonepileptic seizures report more severe migraine than patients with epilepsy

PURPOSE

Clinical observations suggest that psychogenic non-epileptic seizure (PNES) patients often have severe migraine, more severe than epilepsy patients. Investigations into migraine characteristics in patients with PNES are lacking. In this study we tested the hypothesis that, compared to epilepsy patients, PNES patients have more severe migraine, with more frequent and longer duration attacks that cause greater disability.

METHOD

In this observational study, 633 patients with video-EEG proven epilepsy or PNES were identified from the Mayo Clinic Epilepsy Monitoring Unit database. Contacted patients were screened for migraine via a validated questionnaire, and when present, data regarding migraine characteristics were collected. Two-sample t-tests, chi square analyses, and Mann-Whitney U tests were used to compare migraine characteristics in PNES patients to those of epilepsy patients.

RESULTS

Data from 43 PNES patients with migraine and 29 epilepsy patients with migraine were available. Compared to epilepsy patients, PNES patients reported having more frequent headaches (mean 15.1 ± 9.8 vs. 8.1 ± 6.6 headache days/month, p<.001), more frequent migraine attacks (mean 6.5 ± 6.3 vs. 3.8. ± 4.1 migraines/month, p=.028), longer duration migraines (mean 39.5 ± 28.3 vs. 27.3 ± 20.1h, p=.035), and more frequently had non-visual migraine auras (78.6% vs. 46.7% of patients with migraine auras, p=.033). Migraine-related disability scores were not different between PNES and epilepsy patients (median 39, interquartile range 89 vs. 25, interquartile range 60.6, p=.15).

CONCLUSION

Compared to epilepsy patients with migraine, PNES patients with migraine report having a more severe form of migraine with more frequent and longer duration attacks that are more commonly associated with non-visual migraine auras.

[Migraine and epilepsy]

Migraine and epilepsy are both common episodic disorders that share many clinical features and underlying pathophysiological mechanisms. The comorbidity of these two conditions is well known. However, the temporal association between migraine and epilepsy is a controversial issue, since these two conditions may occur in numerous ways. Four types of association between headache and epileptic seizure are recognized: pre-ictal headache, headache as the expression of an epileptic manifestation, post-ictal headache, and inter-ictal headache. The classification of epilepsy by the International League Against Epilepsy did not refer to the epileptic headache. On the other hand, the International Classification of Headache Disorders, 3rd edition (ICHD-3) defines three entities: migraine aura-triggered seizure which sometimes referred to as migralepsy, hemicrania epileptica, and post-ictal headache. However, ICHD-3 mentions that there is a complex and bidirectional association between migraine and epilepsy. Most of the previous reports of migralepsy corresponded to occipital seizures that mimic migraine with aura. The term migralepsy has recently been criticized. Migraine and epilepsy share several pathophysiological mechanisms which involve neurotransmitters and iron channel dysfunctions. There is the hypothesis of a shared genetic susceptibility to migraine and epilepsy. Strong support of a shared genetic basis comes from familial hemiplegic migraine.

The stroke-migraine depolarization continuum

The term spreading depolarization (SD) refers to waves of abrupt, sustained mass depolarization in gray matter of the CNS. SD, which spreads from neuron to neuron in affected tissue, is characterized by a rapid near-breakdown of the neuronal transmembrane ion gradients. SD can be induced by hypoxic conditions--such as from ischemia--and facilitates neuronal death in energy-compromised tissue. SD has also been implicated in migraine aura, where SD is assumed to ascend in well-nourished tissue and is typically benign. In addition to these two ends of the "SD continuum," an SD wave can propagate from an energy-depleted tissue into surrounding, well-nourished tissue, as is often the case in stroke and brain trauma. This review presents the neurobiology of SD--its triggers and propagation mechanisms--as well as clinical manifestations of SD, including overlaps and differences between migraine aura and stroke, and recent developments in neuromonitoring aimed at better diagnosis and more targeted treatments.

Headache in epilepsy: prevalence and clinical features

BACKGROUND

Headache and epilepsy are two relatively common neurological disorders and their relationship is still a matter of debate. Our aim was to estimate the prevalence and clinical features of inter-ictal (inter-IH) and peri-ictal headache (peri-IH) in patients with epilepsy.

METHODS

All patients aged ≥ 17 years referring to our tertiary Epilepsy Centre were consecutively recruited from March to May 2011 and from March to July 2012. They underwent a semi-structured interview including the International Classification Headache Disorders (ICHD-II) criteria to diagnose the lifetime occurrence of headache.χ(2)-test, t-test and Mann-Whitney test were used to compare clinical variables in patients with and without inter-IH and peri-IH.

RESULTS

Out of 388 enrolled patients 48.5 % had inter-IH: migraine in 26.3 %, tension-type headache (TTH) in 19.1 %, other primary headaches in 3.1 %. Peri-IH was observed in 23.7 %: pre-ictally in 6.7 %, ictally in 0.8 % and post-ictally in 19.1 %. Comparing patients with inter-ictal migraine (102), inter-ictal TTH (74) and without inter-IH (200), we found that pre-ictal headache (pre-IH) was significantly represented only in migraineurs (OR 3.54, 95 % CI 1.88-6.66, P < 0.001). Post-ictal headache (post-IH) was significantly associated with both migraineurs (OR 2.60, 95 % CI 1.85-3.64, P < 0.001) and TTH patients (OR 2.05, 95 % CI 1.41-2.98, P < 0.001). Moreover, post-IH was significantly associated with antiepileptic polytherapy (P < 0.001), high seizure frequency (P = 0.002) and tonic-clonic seizures (P = 0.043).

CONCLUSIONS

Migraine was the most represented type of headache in patients with epilepsy. Migraineurs are more prone to develop pre-IH, while patients with any inter-IH (migraine or TTH) are predisposed to manifest a post-IH after seizures.

Migraine and epilepsy: review of the literature

Migraine and epilepsy are disorders that are common, paroxysmal, and chronic. In many ways they are clearly different diseases, yet there are some pathophysiological overlaps, and overlaps in clinical symptomatology, particularly with regard to visual and other sensory disturbances, pain, and alterations of consciousness. Epidemiological studies have revealed that the two diseases are comorbid in a number of individuals. Both are now recognized as originating from electrical disturbances in the brain, although their wider manifestations involve the recruitment of multiple pathogenic mechanisms. An initial excess of neuronal activity in migraine leads to cortical spreading depression and aura, with the subsequent recruitment of the trigeminal nucleus leading to central sensitization and pain. In epilepsy, neuronal overactivity leads to the recruitment of larger populations of neurons firing in a rhythmic manner that constitutes an epileptic seizure. Migraine aura and headaches may act as a trigger for epileptic seizures. Epilepsy is not infrequently accompanied by preictal, ictal, and postictal headaches that often have migrainous features. Genetic links are also apparent between the two disorders, and are particularly evident in the familial hemiplegic migraine syndromes where different mutations can produce either migraine, epilepsy, or both. Also, various medications are found to be effective for both migraine and epilepsy, again pointing to a commonality and overlap between the two disorders.

Auras in generalized epilepsy

OBJECTIVE

We studied the frequency of auras in generalized epilepsy (GE) using a detailed semistructured diagnostic interview.

METHODS

In this cross-sectional study, participants with GE were drawn from the Epilepsy Phenome/Genome Project (EPGP). Responses to the standardized diagnostic interview regarding tonic-clonic (grand mal) seizures were then examined. This questionnaire initially required participants to provide their own description of any subjective phenomena before their "grand mal seizures." Participants who provided answers to these questions were considered to have an aura. All participants were then systematically queried regarding a list of specific symptoms occurring before grand mal seizures, using structured (closed-ended) questions.

RESULTS

Seven hundred ninety-eight participants with GE were identified, of whom 530 reported grand mal seizures. Of these, 112 (21.3%) reported auras in response to the open-ended question. Analysis of responses to the closed-ended questions suggested that 341 participants (64.3%) experienced at least one form of aura.

CONCLUSIONS

Auras typically associated with focal epilepsy were reported by a substantial proportion of EPGP subjects with GE. This finding may support existing theories of cortical and subcortical generators of GE with variable spread patterns. Differences between responses to the open-ended question and closed-ended questions may also reflect clinically relevant variation in patient responses to history-taking and surveys. Open-ended questions may underestimate the prevalence of specific types of auras and may be in part responsible for the underrecognition of auras in GE. In addition, structured questions may influence participants, possibly leading to a greater representation of symptoms.

Evidence for linkage of migraine in Rolandic epilepsy to known 1q23 FHM2 and novel 17q22 genetic loci

Migraine headaches are a common comorbidity in Rolandic epilepsy (RE) and familial aggregation of migraine in RE families suggests a genetic basis not mediated by seizures. We performed a genome-wide linkage analysis of the migraine phenotype in 38 families with RE to localize potential genetic contribution, with a follow-up in an additional 21 families at linked loci. We used two-point and multipoint LOD (logarithm of the odds) score methods for linkage, maximized over genetic models. We found evidence of linkage to migraine at chromosome 17q12-22 [multipoint HLOD (heterogeneity LOD) 4.40, recessive, 99% penetrance], replicated in the second dataset (HLOD 2.61), and suggestive evidence at 1q23.1-23.2, centering over the FHM2 locus (two-point LOD 3.00 and MP HLOD 2.52). Sanger sequencing in 14 migraine-affected individuals found no coding mutations in the FHM2 gene ATP1A2. There was no evidence of pleiotropy for migraine and either reading or speech disorder, or the electroencephalographic endophenotype of RE when the affected definition was redefined as those with migraine or the comorbid phenotype, and pedigrees were reanalyzed for linkage. In summary, we report a novel migraine susceptibility locus at 17q12-22, and a second locus that may contribute to migraine in the general population at 1q23.1-23.2. Comorbid migraine in RE appears genetically influenced, but we did not obtain evidence that the identified susceptibility loci are consistent with pleiotropic effects on other comorbidities in RE. Loci identified here should be fine-mapped in individuals from RE families with migraine, and prioritized for analysis in other types of epilepsy-associated migraine.

Racial and ethnic differences in epilepsy classification among probands in the Epilepsy Phenome/Genome Project (EPGP)

Little is known about the ethnic and racial differences in the prevalence of generalized and focal epilepsy among patients with non-acquired epilepsies. In this study, we examined epilepsy classification and race/ethnicity in 813 probands from sibling or parent-child pairs with epilepsy enrolled in the Epilepsy Genome/Phenome Project (EPGP). Subjects were classified as generalized epilepsy (GE), non-acquired focal epilepsy (NAFE), mixed epilepsy syndrome (both generalized and focal), and unclassifiable, based on consensus review of semiology and available clinical, electrophysiology, and neuroimaging data. In this cohort, 628 (77.2%) subjects identified exclusively as Caucasian/white and 65 (8.0%) subjects reported African ancestry, including subjects of mixed-race. Of the Caucasian/white subjects, 357 (56.8%) had GE, 207 (33.0%) had NAFE, 32 (5.1%) had a mixed syndrome, and 32 (5.1%) were unclassifiable. Among subjects of African ancestry, 28 (43.1%) had GE, 27 (41.5%) had NAFE, 2 (3.1%) had a mixed syndrome, and 8 (12.3%) were unclassifiable. There was a higher proportion of subjects with GE compared to other syndromes among Caucasians/whites compared to subjects with African ancestry (OR 1.74, 95% CI: 1.04-2.92, two-tailed Fisher's exact test, p=0.036). There was no difference in the rate of GE among subjects reporting Hispanic ethnicity (7.6% of total) when adjusted for race (Caucasian/white vs non-Caucasian/white; OR 0.65, 95% CI: 0.40-1.06, p>0.05). The proportion of participants with unclassifiable epilepsy was significantly greater in those of African-American descent. In a group of patients with epilepsy of unknown etiology and an affected first degree relative, GE is more common among Caucasian/white subjects than among those with African ancestry. These findings suggest there may be geographical differences in the distribution of epilepsy susceptibility genes and an effect of genetic background on epilepsy phenotype. However, the results should be interpreted with caution because of the low numbers of African-Americans in this cohort and more limited diagnostic data available for epilepsy classification in these subjects compared to Caucasians/whites.

Phospholipase C activity increases in cerebrospinal fluid from migraineurs in proportion to the number of comorbid conditions: a case-control study

Background

Migraineurs are more often afflicted by comorbid conditions than those without primary headache disorders, though the linking pathophysiological mechanism(s) is not known. We previously reported that phosphatidylcholine-specific phospholipase C (PC-PLC) activity in cerebrospinal fluid (CSF) increased during migraine compared to the same individual’s well state. Here, we examined whether PC-PLC activity from a larger group of well-state migraineurs is related to the number of their migraine comorbidities.

Methods

In a case–control study, migraineurs were diagnosed using International Headache Society criteria, and controls had no primary headache disorder or family history of migraine. Medication use, migraine frequency, and physician-diagnosed comorbidities were recorded for all participants. Lumbar CSF was collected between the hours of 1 and 5 pm, examined immediately for cells and total protein, and stored at −80°C. PC-PLC activity in thawed CSF was measured using a fluorometric enzyme assay. Multivariable logistic regression was used to evaluate age, gender, medication use, migraine frequency, personality scores, and comorbidities as potential predictors of PC-PLC activity in CSF.

Results

A total of 18 migraineurs-without-aura and 17 controls participated. In a multivariable analysis, only the number of comorbidities was related to PC-PLC activity in CSF, and only in migraineurs [parameter estimate (standard error) = 1.77, p = 0.009].

Conclusion

PC-PLC activity in CSF increases with increasing number of comorbidities in migraine-without-aura. These data support involvement of a common lipid signaling pathway in migraine and in the comorbid conditions.