Reflex seizure triggering: Learning about seizure producing systems

Exploring shared triggers and potential etiopathogenesis between migraine and idiopathic/genetic epilepsy: Insights from a multicenter tertiary-based study

INTRODUCTION

Migraine and epilepsy are two episodic disorders that share common pathophysiological mechanisms. The aim of our research was to assess the possible shared etiopathogenesis by analyzing the relations of headache, and seizure triggers, based on information obtained from a national cohort surveying the headache characteristics of 809 patients who had been diagnosed with idiopathic/genetic epilepsy.

MATERIAL AND METHODS

Our study utilized data from a multi-center, nationwide investigation of headaches in 809 patients with idiopathic/genetic epilepsy. Out of these, 508 patients reported complaints related to any type of headache (333 Migraines, 175 Headaches of other types). In the initial phase of the study encompassing the entire sample of 809 epilepsy patients, differences in seizure triggers were assessed between the migraine group (n = 333) and the non-migraine group (n = 476). Additionally, the subsequent part of the study pertains to a subgroup of the entire patient group, namely those affected by all types of headaches (n = 508), and differences in headache triggers were assessed among migraine patients (n = 333) and those with other types of headaches (n = 175). Similar differences were observed between epilepsy patients with and without a family history of epilepsy.

RESULTS

The most frequently reported seizure triggers in all I/GE group (n = 809) were stress (23%), sleep deprivation (22%) and fatigue (18%), respectively. The most frequently reported headache triggers in migraine patients were stress (31%), sleep deprivation (28%), and noise (26%). The occurrence of menstruation-triggered seizures in individuals with migraine and I/GE was found to be considerably higher than those without migraine. The most common triggers for seizure and headache among the individuals with a positive family history of epilepsy were determined to be light stimuli and sleep deprivation.

CONCLUSION

In conclusion, our study provides valuable insights into the overlapping triggers including sleep patterns, stress levels, and menstrual cycles, etc. and potential shared etiology of migraine and I/GE. Recognizing these connections may facilitate the development of more precise therapeutic strategies and underscore the significance of adopting a holistic, multidisciplinary approach to the management of these intricate neurological conditions. Further research is essential to explore in greater depth the shared mechanisms underpinning these associations and their implications for clinical practice.

Checkmate: Chess-induced reflex seizures in patient with juvenile myoclonic epilepsy

Content available: Video

Population Pharmacokinetics and Exposure-Safety of Lipophilic Conjugates Prodrug DP-VPA in Healthy Chinese Subjects for Dose Regime Exploring

Phospholipid-valproic acid (DP-VPA)is a prodrug for treating epilepsy. The present study explored the pharmacokinetics (PK) and exposure safety of DP-VPA to provide a basis for future studies exploring the safe dosage and therapeutic strategies for epilepsy. The study included a randomized placebo-controlled dose-escalation tolerance evaluation trial and a randomized triple crossover food-effect trial in healthy Chinese volunteers. A population pharmacokinetic (PopPK) model was established to analyze the PK of DP-VPA and active metabolite VPA. The exposure safety was assessed with the adverse drug reaction (ADR) in CNS. The PopPK of DP-VPA and metabolite VPA fitted a two-compartment model coupling one-compartment with Michaelis-Menten metabolite kinetics and first-order elimination. The absorption processes after single oral administration of DP-VPA tablet demonstrated nonlinear characteristics, including 0-order kinetic phase and time-dependent phase fitting Weibull distribution. The final model indicated that the DP-VPA PK was significantly affected by dosage and food. The exposure-safety relationship demonstrated a generalized linear regression; mild/moderate ADRs occurred in some subjects with 600 mg and all subjects with 1500 mg of DP-VPA, and no severe ADRs were reported up to 2400 mg. In conclusion, the study established a PopPK model describing the processing of DP-VPA and VPA in healthy Chinese subjects. DP-VPA showed good tolerance after a single dose of 600-2400 mg with nonlinear PK and was affected by dosage and food. Based on the association between neurological ADRs and higher exposure to DP-VPA by exposure-safety analysis, 900-1200 mg was recommended for subsequent study of safety and clinical effectiveness.

Myoclonus as a Manifestation of Reflex Seizures

SUMMARY

Myoclonus is a motor symptom commonly associated with reflex seizures in people with idiopathic generalized epilepsies. The most frequently observed triggers of myoclonus are related to visual stimuli, including flashing lights or patterns; nonetheless, myoclonus can also be activated by movement, speech or reading, calculations, and praxis. Reflex myoclonic seizures may be the hallmark of a reflex epilepsy, but it may lead to the diagnosis of generalized epilepsy syndromes. In the setting of idiopathic generalized epilepsies, reflex myoclonus can persist despite optimal medical therapies and may be a marker for active, even medically intractable, epilepsy. In this article, the clinical significance, diagnosis, and treatment of myoclonus, associated with visual stimulation, movement, and praxis, will be reviewed.

Reflex seizures induced by micturition: a case report

Background

Reflex seizures (RS) induced by micturition are extremely rare, and the clinical and electroencephalogram features of RS are not widely known among clinicians. In particular, the origin of the epileptic area is still unclear.

Case presentation

An 8-year-old girl who had generalized tonic-clonic seizures was diagnosed with RS induced by micturition based on the clinical manifestation and EEG recordings. We also reviewed the clinical and EEG characteristics of RS induced by micturition in literature by searching the databases of PubMed and MEDLINE using keywords “micturition reflex seizure”, “reflex seizure induced by micturition”, and “micturition induced seizure” by January 2022. We speculate that the mechanism of micturition-induced RS may involve excessive neuronal excitation in regions that participate in micturition.

Conclusions

The RS in this patient was considered to be induced by micturition. Awareness should be raised to this rare form of RS among practitioners.

Sleep and Epilepsy Link by Plasticity

We aimed to explore the link between NREM sleep and epilepsy. Based on human and experimental data we propose that a sleep-related epileptic transformation of normal neurological networks underlies epileptogenesis. Major childhood epilepsies as medial temporal lobe epilepsy (MTLE), absence epilepsy (AE) and human perisylvian network (PN) epilepsies - made us good models to study. These conditions come from an epileptic transformation of the affected functional systems. This approach allows a system-based taxonomy instead of the outworn generalized-focal classification. MTLE links to the memory-system, where epileptic transformation results in a switch of normal sharp wave-ripples to epileptic spikes and pathological high frequency oscillations, compromising sleep-related memory consolidation. Absence epilepsy (AE) and juvenile myoclonic epilepsy (JME) belong to the corticothalamic system. The burst-firing mode of NREM sleep normally producing sleep-spindles turns to an epileptic working mode ejecting bilateral synchronous spike-waves. There seems to be a progressive transition from AE to JME. Shared absences and similar bilateral synchronous discharges show the belonging of the two conditions, while the continuous age windows - AE affecting schoolchildren, JME the adolescents - and the increased excitability in JME compared to AE supports the notion of progression. In perisylvian network epilepsies - idiopathic focal childhood epilepsies and electrical status epilepticus in sleep including Landau-Kleffner syndrome - centrotemporal spikes turn epileptic, with the potential to cause cognitive impairment. Postinjury epilepsies modeled by the isolated cortex model highlight the shared way of epileptogenesis suggesting the derailment of NREM sleep-related homeostatic plasticity as a common step. NREM sleep provides templates for plasticity derailing to epileptic variants under proper conditions. This sleep-origin explains epileptiform discharges' link and similarity with NREM sleep slow oscillations, spindles and ripples. Normal synaptic plasticity erroneously overgrowing homeostatic processes may derail toward an epileptic working-mode manifesting the involved system's features. The impact of NREM sleep is unclear in epileptogenesis occurring in adolescence and adulthood, when plasticity is lower. The epileptic process interferes with homeostatic synaptic plasticity and may cause cognitive impairment. Its type and degree depends on the affected network's function. We hypothesize a vicious circle between sleep end epilepsy. The epileptic derailment of normal plasticity interferes with sleep cognitive functions. Sleep and epilepsy interconnect by the pathology of plasticity.

Reflex epileptic features in patients with focal epilepsy of unknown cause

OBJECTIVES

There is a gap of knowledge regarding reflex seizures in patients with focal epilepsy of unknown cause (FEUC). We aimed to evaluate the prevalence, demographic and clinical characteristics of reflex seizures in patients with FEUC to provide an insight to the underlying ictogenic mechanisms and to draw attention to this important but under-investigated topic.

PATIENTS AND METHODS

After carefully questioning for reflex triggers, 186 patients diagnosed according to ILAE criteria and followed-up for a minimum of 5 years were included. The demographic and clinical properties as well as electrophysiological and neuroimaging data of these patients were reevaluated and compared to the patients without reflex seizures.

RESULTS

The reflex seizure rate was 6.5 % in patients with FEUC. Patients with reflex features had lower monotherapy rates (p = 0.005) and higher major depression rates (p = 0.001) than patients without reflex features. The distribution of the patients according to their reflex triggers were as follows: hot-water induced (n = 3, 25 %), photosensitive (n = 2, 16.7 %), eating- induced (n = 2, 16.7 %), musicogenic (n = 2, 16.7 %), startle induced (n = 2, 16.7 %) and both musicogenic and startle type (n = 1, 8.3 %) respectively. The drug resistance rate of patients with reflex seizures was 25 % (n = 3). One patient with drug resistant reflex seizures showed benefit from epilepsy surgery and became seizure-free during last 3 years of follow-up.

CONCLUSION

A careful and thoroughly history taking specifically questioning and focusing on seizure inducing factors in patients with FEUC is needed to confirm the presence of reflex seizures in patients with FEUC, who had higher rates of polytherapy and major depression. Elaborative evaluation of reflex features in FEUC might contribute to effective seizure control, ensure new therapeutic approaches, enlighten the obscurity and the resulting anxiety of having a diagnosis of FEUC in epilepsy patients.