Headache and Epilepsy

Potential of focal cortical dysplasia in migraine pathogenesis

Focal cortical dysplasias are abnormalities of the cerebral cortex associated with an elevated risk of neurological disturbances. Cortical spreading depolarization/depression is a correlate of migraine aura/headache and a trigger of migraine pain mechanisms. However, cortical spreading depolarization/depression is associated with cortical structural changes, which can be classified as transient focal cortical dysplasias. Migraine is reported to be associated with changes in various brain structures, including malformations and lesions in the cortex. Such malformations may be related to focal cortical dysplasias, which may play a role in migraine pathogenesis. Results obtained so far suggest that focal cortical dysplasias may belong to the causes and consequences of migraine. Certain focal cortical dysplasias may lower the threshold of cortical excitability and facilitate the action of migraine triggers. Migraine prevalence in epileptic patients is higher than in the general population, and focal cortical dysplasias are an established element of epilepsy pathogenesis. In this narrative/hypothesis review, we present mainly information on cortical structural changes in migraine, but studies on structural alterations in deep white matter and other brain regions are also presented. We develop the hypothesis that focal cortical dysplasias may be causally associated with migraine and link pathogeneses of migraine and epilepsy.

Headache Is a Common Aura in Patients with Generalized Seizures

Background and Purpose

Although aura in epilepsy is usually considered as a phenomenon in patients with focal seizures, headache can occur as an aura or solitary epileptic symptom in patients with generalized seizures.

Methods

We performed a 14-year retrospective study of patients with generalized seizures and analyzed the proportion and characteristics of patients with auras including headache.

Results

Among the 102 patients diagnosed with generalized seizures, aura was reported in 45 patients and headache was the most common aura in 26 patients. The age of onset of seizures was significantly lower in patients with headache as an aura than in patients without headache (14.8±3.8 vs. 24.7±16.2; p=0.003).

Conclusions

Our study showed that headache was the most common aura in patients with generalized seizures and patients with a younger age of onset of seizures were more likely to experience headache as an aura in these patients.

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.

Primary headache disorders in epileptic adults

Background

Epilepsy and primary headache disorders are two relatively common neurological disorders and their relationship is still a matter of debate. We aimed to estimate the prevalence and clinical features of primary headache disorders in patients with epilepsy.

Methods

62 subjects aged ≥ 18 years were recruited from the hospital’s neurology outpatient clinic in the period from January to April 2018. The subjects were further divided into two equal groups, epileptics and non-epileptics. They underwent a semi-structured interview including the ILAE 2017 epilepsy classification and the ICHD III-beta criteria for headache. Patients' demographic data and clinical characteristics of epilepsy and headache and temporal relationships between them were assessed. Patients who experienced headaches were grouped based on the type of headaches and on whether their headaches occurred in the pre-ictal, post-ictal or inter-ictal period.

Results

Primary headache disorders were more common in epileptic group (61.3%) than the non-epileptic group (32.2%) (p = 0.021). The tension-type headache was the most common (45.2%) followed by migraine-type headache (12.9%) in the epileptic group. Post-ictal headache was the most common type (29%). Inter-ictal headaches were significantly related to "focal to bilateral tonic–clonic" seizures (p = 0.046). The prevalence of headache among patients on polytherapy (69.2%) was higher than that of patients on monotherapy (52.9%).

Conclusions

In this study, headache was more common in epileptic patients. TTH was the most represented type of headache in patients with epilepsy. Headache occurred in patients with epilepsy most frequently during the post-ictal period.

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.

Headache in patients with mesial temporal lobe epilepsy with hippocampal sclerosis

OBJECTIVE

It is remarkable that epilepsy and migraine are similar diseases with many parallel clinical features, as well as sharing common pathophysiological mechanisms. However, the pathogenetic role of hippocampal sclerosis (HS) in epilepsy and headache coexistence has not been clarified. In this study, we aimed to investigate the frequency of headache/migraine and the relationship between headache and HS lateralizations in patients with mesial temporal lobe epilepsy (MTLE), accompanied by HS.

METHODS

Consecutive patients with mesial temporal lobe epilepsy with hippocampal sclerosis (HS-MTLE) followed up in epilepsy outpatient clinic were included in this study, with their demographic and clinical characteristics, HS lateralization, and side (unilateral-right-left, bilateral), which were recorded. Using the questionnaires, the type of headache [migraine, tension headache (TTH)] was determined. Patients in whom migraine and TTH could not be completely separated were recruited for the unclassified group. The temporal relationship of headache and seizures (peri-ictal and/or interictal), pain lateralization, and side (unilateral-right-left, bilateral, unilateral + bilateral) were likewise determined.

RESULTS

There were 56 patients (30 females, 26 males; mean age 36.9 ± 12.1 years; mean epilepsy duration 19.3 ± 12.5 years) included in the study. Thirty-one patients (55.4%) stated they had a headache: of these, eighteen (32.1%) had migraine and 9 (16.1%) had TTH. Migraine accounted for 58.1% of headaches and TTHs was 29%. Headache was unilateral in 15 patients, and bilateral or bilateral + unilateral in 16 patients. Of patients with migraine, pain was unilateral in 10, and bilateral or bilateral + unilateral in 8. HS was right-sided in 24 patients, left-sided in 30 patients, and bilateral in 2 patients. In patients with right-sided HS, it was an ipsilateral headache; bilateral headache was found to be more common in patients with left-sided HS (p = 0.029). No relationship was found between the lateralization of the headache and the side of HS in patients with migraine.

CONCLUSION

The results of our study showed that approximately half the patients with HS-MTLE did have a headache, with one third noting migraine type headache; this highlighted that HS may play a pathogenetic role in the development of headache, especially migraine, in patients with epilepsy. Further comprehensive studies will enable us to understand whether accompanying headache, especially migraine attacks in patients with epilepsy, can be determinant for HS-MTLE, as well as if it has a lateralizing value for HS.

Mouse Models of Familial Hemiplegic Migraine for Studying Migraine Pathophysiology

Migraine, an extremely disabling neurological disorder, has a strong genetic component. Since monogenic mi-graines (resulting from mutations or changes in a single gene) may help researchers discover migraine pathophysiology, transgenic mice models harboring gene mutations identified in Familial Hemiplegic Migraine (FHM) patients have been gen-erated. Studies in these FHM mutant mice models have shed light on the mechanisms of migraine and may aid in the identifi-cation of novel targets for treatment. More specifically, the studies shed light on how gene mutations, hormones, and other factors impact the pathophysiology of migraine. The models may also be of relevance to researchers outside the field of mi-graine as some of their aspects are relevant to pain in general. Additionally, because of the comorbidities associated with mi-graine, they share similarities with the mutant mouse models of epilepsy, stroke, and perhaps depression. Here, we review the experimental data obtained from these mutant mice and focus on how they can be used to investigate the pathophysiology of migraine, including synaptic plasticity, neuroinflammation, metabolite alterations, and molecular and behavioral mecha-nisms of pain.

Phase clustering in transcranial magnetic stimulation-evoked EEG responses in genetic generalized epilepsy and migraine

BACKGROUND

Epilepsy and migraine are paroxysmal neurological conditions associated with disturbances of cortical excitability. No useful biomarkers to monitor disease activity in these conditions are available. Phase clustering was previously described in electroencephalographic (EEG) responses to photic stimulation and may be a potential epilepsy biomarker.

OBJECTIVE

The objective of this study was to investigate EEG phase clustering in response to transcranial magnetic stimulation (TMS), compare it with photic stimulation in controls, and explore its potential as a biomarker of genetic generalized epilepsy or migraine with aura.

METHODS

People with (possible) juvenile myoclonic epilepsy (JME), migraine with aura, and healthy controls underwent single-pulse TMS with concomitant EEG recording during the interictal period. We compared phase clustering after TMS with photic stimulation across the groups using permutation-based testing.

RESULTS

We included eight people with (possible) JME (five off medication, three on), 10 with migraine with aura, and 37 controls. The TMS and photic phase clustering spectra showed significant differences between those with epilepsy without medication and controls. Two phase clustering-based indices successfully captured these differences between groups. One participant was tested multiple times. In this case, the phase clustering-based indices were inversely correlated with the dose of antiepileptic medication. Phase clustering did not differ between people with migraine and controls.

CONCLUSION

We present methods to quantify phase clustering using TMS-EEG and show its potential value as a measure of brain network activity in genetic generalized epilepsy. Our results suggest that the higher propensity to phase clustering is not shared between genetic generalized epilepsy and migraine.

Novel Therapeutic Targets Against Spreading Depression

Migraine is among the most prevalent and disabling neurological diseases in the world. Cortical spreading depression (SD) is an intense wave of neuronal and glial depolarization underlying migraine aura, and a headache trigger, which has been used as an experimental platform for drug screening in migraine. Here, we provide an overview of novel therapeutic targets that show promise to suppress SD, such as acid-sensing ion channels, casein kinase Iδ, P2X7-pannexin 1 complex, and neuromodulation, and outline the experimental models and essential quality measures for rigorous and reproducible efficacy testing.

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.

Epilepsy and headaches: Further evidence of a link

OBJECTIVE

Epilepsy and primary headaches are two of the most common neurologic conditions that share some common clinical characteristics, and can affect individuals of all age groups around the world. In recent years, the underlying pathophysiologic mechanisms potentially common to both headaches and epileptic seizures have been the subject of scrutiny. The objective of this study was to determine the frequencies and types of headaches in patients with epilepsy, and evaluate any temporal relationship with epileptic seizures.

METHOD

Demographic data, epilepsy durations, seizure frequencies, seizure types and antiepileptic medications used were captured of 349 patients who were followed up at our epilepsy outpatient clinic. Patients who experienced headaches were grouped based on the type of headaches and on whether their headaches occurred in the preictal, postictal or interictal period.

RESULT

Three hundred forty-nine patients (190 females, 159 males) were enrolled in the study. The patients' average age was 30.9±13.1 years, and average epilepsy duration was 13.5±10.9 years. The types of epileptic seizures were partial in 19.8% of patients, generalized in 57.9%, and secondary generalized in 20.3% of patients. Some 43.6% of the patients did not experience headaches, and 26.9% had migraine and 17.2% tension-type headaches. Headaches could not be classified in 12.3% of patients. The headaches occurred preictally in 9.6%, postictally in 41.6% and interictally in 8.6% of patients. The ratio of headaches was lower in male patients compared with females, and females experienced migraine-type headaches more frequently compared with males (p=0.006). Migraine-type headaches were less frequent a mong patients who experienced less than one seizure per year, but more frequent (p=0.017) among those who experienced more than one seizure per month, but less than one seizure per week. Migraine-type headaches were significantly more frequent (p=0.015) among patients receiving polytherapy compared with patients receiving monotherapy.

CONCLUSION

The results of this study suggest that headaches, particularly migraine-type headaches, were frequently experienced by patients with epilepsy, postictal headaches were more common, and the frequency of migraine attacks could be linked with seizure frequency and the type of treatment.

Animal models of monogenic migraine

Migraine is a highly prevalent and disabling neurological disorder with a strong genetic component. Rare monogenic forms of migraine, or syndromes in which migraine frequently occurs, help scientists to unravel pathogenetic mechanisms of migraine and its comorbidities. Transgenic mouse models for rare monogenic mutations causing familial hemiplegic migraine (FHM), cerebral autosomal dominant arteriopathy with subcortical infarcts and leukoencephalopathy (CADASIL), and familial advanced sleep-phase syndrome (FASPS), have been created. Here, we review the current state of research using these mutant mice. We also discuss how currently available experimental approaches, including epigenetic studies, biomolecular analysis and optogenetic technologies, can be used for characterization of migraine genes to further unravel the functional and molecular pathways involved in migraine.

Headache as an Aura of Epilepsy: Video-EEG Monitoring Study

BACKGROUND

Headache can be associated with epilepsy as a pre-ictal, ictal, or post-ictal phenomenon; however, studies of patients with headache as an epileptic aura are scarce. We performed the present study to investigate the incidence and characteristics of headache as an epileptic aura, via confirmation of electroencephalography (EEG) changes by video-EEG monitoring.

METHODS

Data of aura and clinical seizure episodes of 831 consecutive patients who undertook video-EEG monitoring were analyzed retrospectively. For patients who had headache as an aura, information on the detailed features of headache was acquired, including location, nature, duration, and the presence of accompanying symptoms. Video-recorded clinical seizures, EEG findings, and neuroimaging data were used to determine the ictal onset areas in the patients.

RESULTS

Six out of 831 (0.7%) patients experienced headache as aura (age range, 25-52 years), all of whom had partial seizures. The incidence of pre-ictal headache was 6.3% (25/831), and post-ictal headache was 30.9% (257/831). In patients with headache as aura, five patients described headache as the most frequent aura, and headache was the second most frequent aura in one patient. The characteristics of headache were hemicrania epileptica in two patients, tension-type headache in another two patients, and migraine-like headache in the remaining two patients. No patient met the diagnostic criteria of ictal epileptic headache or migraine aura-triggered seizure.

CONCLUSION

Our study showed that headache as an aura is uncommon in adult patients with epilepsy, and that headache can present as diverse features, including hemicrania epileptica, tension-type headache, and migraine-like headache. Further studies are necessary to characterize the features of headache as an epileptic aura in adult patients with epilepsy.

Ictal epileptic headache revealing non convulsive status epilepticus in a case of eyelid myoclonia with absences

Epileptic seizures and headache attacks are two common neurologic phenomena characterized by paroxysmal alteration of brain functions followed by complete restauration of the baseline condition. Headache and epilepsy are related in numerous ways, and they often co-occur. Although the link between these two diseases is not completely clear, several clinical, physiopathological and therapeutic features overlap. Headache is reported in association with epileptic seizures as a pre-ictal, ictal or post-ictal phenomenon. We present the case of a 40 year-old woman affected by eyelid myoclonia with absences (EMA) with a history of prolonged headache attacks. A video-EEG recording performed during one of these episodes showed subcontinuous epileptic activity consisting of generalized spike-and-wave discharges (GSWDs), clinically associated with tensive headache. Our work represents one of the few well EEG-documented cases of ictal epileptic headache in idiopathic generalized epilepsy (IGE).

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 mimics

The symptoms of migraine are non-specific and can be present in many other primary and secondary headache disorders, which are reviewed. Even experienced headache specialists may be challenged at times when diagnosing what appears to be first or worst, new type, migraine status, and chronic migraine.

Headache and sleep: shared pathophysiological mechanisms

OBJECTIVE

The objective of the current article is to review the shared pathophysiological mechanisms which may underlie the clinical association between headaches and sleep disorders.

BACKGROUND

The association between sleep and headache is well documented in terms of clinical phenotypes. Disrupted sleep-wake patterns appear to predispose individuals to headache attacks and increase the risk of chronification, while sleep is one of the longest established abortive strategies. In agreement, narcoleptic patients show an increased prevalence of migraine compared to the general population and specific familial sleep disorders have been identified to be comorbid with migraine with aura.

CONCLUSION

The pathophysiology and pharmacology of headache and sleep disorders involves an array of neural networks which likely underlie their shared clinical association. While it is difficult to differentiate between cause and effect, or simply a spurious relationship the striking brainstem, hypothalamic and thalamic convergence would suggest a bidirectional influence.

Clinical factors associated with postictal headache in Chinese patients with partial epilepsy

PURPOSE

To investigate the incidence of postictal headache (PIH) and the factors potentially related to the occurrence of PIH in a Chinese epileptic center.

METHODS

Consecutive adult patients with epilepsy, referred to the outpatient clinic of the Epilepsy Center of the PLA General Hospital between February 01, 2012, and May 10, 2013, were recruited to this study. 854 patients with partial epilepsy completed a questionnaire regarding headache, 466 patients with temporal lobe epilepsy (TLE), 82 patients with occipital lobe epilepsy (OLE) and 306 patients with frontal lobe epilepsy (FLE). A semi-structured interview was performed in those who confirmed headache.

RESULTS

PIH occurred in 328 (38.41%) of the subjects. By type of epilepsy, PIH was found in 164 (35.19%) of the patients with TLE, 46 (56.01%) of the patients with OLE, and 118 (38.56%) of the patients with FLE. The incidence of PIH in OLE was significantly higher than in TLE and FLE (P<0.05). It occurs more frequently after generalized tonic-clonic seizures than other seizure types. Logistic regression analysis revealed that age at onset, type of seizure and classification of epilepsy were each significantly related to the occurrence of PIH.

CONCLUSION

The results of our study revealed possible relationships between PIH and the region of epileptic focus and area of spread of epileptic discharges.