Refractory Epilepsy: Clinical Overview

Targeting ischemia-induced KCC2 hypofunction rescues refractory neonatal seizures and mitigates epileptogenesis in a mouse model

[Figure: see text].

Fluoxetine as adjunctive therapy in pediatric patients with refractory epilepsy: A retrospective analysis

Approximately 30 % of children with epilepsy develop refractory epilepsy, which has a major impact on neurodevelopmental processes, cognitive functioning, and daily life. Furthermore, children with highly refractory epilepsy are at particular risk of sudden unexpected death. Fluoxetine, a selective serotonin reuptake inhibitor (SSRI), has shown antiseizure action and was associated with a decreased severity of peri-ictal hypoxemia in adult patients with focal epilepsy. However, therapeutic studies on SSRI use in children are scarce - particularly in epileptic patients. We retrospectively recruited 14 pediatric patients; inclusion criteria were i) refractory epilepsy ii) frequent generalized or focal seizures (more than 1/week) iii) treated with fluoxetine as adjunctive therapy for one month at least. We analyzed their clinical outcome (efficacy and tolerance). The median age at fluoxetine initiation was 9.5 years (2-19), and fluoxetine was combined with a median number of 4 (2-6) anti-seizure medications. The median dose of fluoxetine at the last follow-up was 0.4 mg/kg/day (0.2-0.8). Among the 14 patients, we observed 6 (43 %) good responders. Complete freedom from seizures with cyanosis was reached in 3 (21 %) patients, and only one patient with early-onset epilepsy related to an FHF1 mutation was completely seizure-free. None of the recruited patients experienced seizure worsening, and 8 patients showed no effect on seizure frequency. Fluoxetine as adjunctive therapy in refractory epilepsy could be a beneficial therapeutic option. Future prospective, randomized and controlled studies are needed to study the efficacy of fluoxetine better.

The role of efflux transporters and metabolizing enzymes in brain and peripheral organs to explain drug-resistant epilepsy

Drug‐resistant epilepsy has been explained by different mechanisms. The most accepted one involves overexpression of multidrug transporters proteins at the blood brain barrier and brain metabolizing enzymes. This hypothesis is one of the main pharmacokinetic reasons that lead to the lack of response of some antiseizure drug substrates of these transporters and enzymes due to their limited entrance into the brain and limited stay at the sites of actions. Although uncontrolled seizures can be the cause of the overexpression, some antiseizure medications themselves can cause such overexpression leading to treatment failure and thus refractoriness. However, it has to be taken into account that the inductive effect of some drugs such as carbamazepine or phenytoin not only impacts on the brain but also on the rest of the body with different intensity, influencing the amount of drug available for the central nervous system. Such induction is not only local drug concentration but also time dependent. In the case of valproic acid, the deficient disposition of ammonia due to a malfunction of the urea cycle, which would have its origin in an intrinsic deficiency of L‐carnitine levels in the patient or by its depletion caused by the action of this antiseizure drug, could lead to drug‐resistant epilepsy. Many efforts have been made to change this situation. In order to name some, the administration of once‐daily dosing of phenytoin or the coadministration of carnitine with valproic acid would be preferable to avoid iatrogenic refractoriness. Another could be the use of an adjuvant drug that down‐regulates the expression of transporters. In this case, the use of cannabidiol with antiseizure properties itself and able to diminish the overexpression of these transporters in the brain could be a novel therapy in order to allow penetration of other antiseizure medications into the brain.

Long-term brain network reorganization predicts responsive neurostimulation outcomes for focal epilepsy

Responsive neurostimulation (RNS) devices, able to detect imminent seizures and to rapidly deliver electrical stimulation to the brain, are effective in reducing seizures in some patients with focal epilepsy. However, therapeutic response to RNS is often slow, is highly variable, and defies prognostication based on clinical factors. A prevailing view holds that RNS efficacy is primarily mediated by acute seizure termination; yet, stimulations greatly outnumber seizures and occur mostly in the interictal state, suggesting chronic modulation of brain networks that generate seizures. Here, using years-long intracranial neural recordings collected during RNS therapy, we found that patients with the greatest therapeutic benefit undergo progressive, frequency-dependent reorganization of interictal functional connectivity. The extent of this reorganization scales directly with seizure reduction and emerges within the first year of RNS treatment, enabling potential early prediction of therapeutic response. Our findings reveal a mechanism for RNS that involves network plasticity and may inform development of next-generation devices for epilepsy.

miR-485's anti-drug resistant epilepsy effects by regulating SV2A/PSD-95 and targeting ABCC1 and neuronal signaling-transduction proteins in hippocampus of rats

AIM

Drug-resistant epilepsy (DRE), most subsequently developing refractory epilepsy, causes a significant burden to the society. microRNAs have been demonstrated as key regulators and therapeutic targets in epilepsy. Accordingly, the aim of the present study was to test whether miR-485 could be a potential target for DRE.

METHODS AND RESULTS

An in vivo DRE model was developed in Sprague-Dawley rats by lithium chloride-pilocarpine and screened by antiepileptic drugs. We found that miR-485-5p in hippocampus was significant downregulated at early stage and recovered to normal level at late stage of DRE. Overexpression of miR-485-5p in dentate gyrus (DG) of hippocampus in DRE rats could significantly decrease the frequency of seizures and the numbers of epileptiform spikes of hippocampal DG neuron, and could specifically decrease SV2A expression without affecting PSD-95 expression in DG. Furthermore, miR-485-5p overexpression could significantly downregulate the expression of efflux transporter related to multidrug resistance (ABCC1) in hippocampus at late stage of DRE. Finally, a specific expression pattern of neuronal signaling-transduction proteins (LRP4, MDM4, p53, and TMBIM1) for DRE was observed, and miR-485-5p overexpression could modulate these proteins' expression levels toward normal in hippocampus both at early and late stage of DRE.

CONCLUSION

Collectively, these results suggest that miR-485 was a potential target for anti-DRE, and this effects might be partially via miR-485-5p/homeostatic-synaptic plasticity-molecule axis and/or targeting efflux transporter (ABCC1) and other neuronal signaling-transduction proteins (LRP4, MDM4, p53, and TMBIM1).

Nonperiodic stimulation for the treatment of refractory epilepsy: Applications, mechanisms, and novel insights

Electrical stimulation of the central nervous system is a promising alternative for the treatment of pharmacoresistant epilepsy. Successful clinical and experimental stimulation is most usually carried out as continuous trains of current or voltage pulses fired at rates of 100 Hz or above, since lower frequencies yield controversial results. On the other hand, stimulation frequency should be as low as possible, in order to maximize implant safety and battery efficiency. Moreover, the development of stimulation approaches has been largely empirical in general, while they should be engineered with the neurobiology of epilepsy in mind if a more robust, efficient, efficacious, and safe application is intended. In an attempt to reconcile evidence of therapeutic effect with the understanding of the underpinnings of epilepsy, our group has developed a nonstandard form of low-frequency stimulation with randomized interpulse intervals termed nonperiodic stimulation (NPS). The rationale was that an irregular temporal pattern would impair neural hypersynchronization, which is a hallmark of epilepsy. In this review, we start by briefly revisiting the literature on the molecular, cellular, and network level mechanisms of epileptic phenomena in order to highlight this often-overlooked emergent property of cardinal importance in the pathophysiology of the disease. We then review our own studies on the efficacy of NPS against acute and chronic experimental seizures and also on the anatomical and physiological mechanism of the method, paying special attention to the hypothesis that the lack of temporal regularity induces desynchronization. We also put forward a novel insight regarding the temporal structure of NPS that may better encompass the set of findings published by the group: the fact that intervals between stimulation pulses have a distribution that follows a power law and thus may induce natural-like activity that would compete with epileptiform discharge for the recruitment of networks. We end our discussion by mentioning ongoing research and future projects of our lab.

Astrocytic Ca2+ Signaling in Epilepsy

Epilepsy is one of the most common neurological disorders – estimated to affect at least 65 million worldwide. Most of the epilepsy research has so far focused on how to dampen neuronal discharges and to explain how changes in intrinsic neuronal activity or network function cause seizures. As a result, pharmacological therapy has largely been limited to symptomatic treatment targeted at neurons. Given the expanding spectrum of functions ascribed to the non-neuronal constituents of the brain, in both physiological brain function and in brain disorders, it is natural to closely consider the roles of astrocytes in epilepsy. It is now widely accepted that astrocytes are key controllers of the composition of the extracellular fluids, and may directly interact with neurons by releasing gliotransmitters. A central tenet is that astrocytic intracellular Ca²⁺ signals promote release of such signaling substances, either through synaptic or non-synaptic mechanisms. Accruing evidence suggests that astrocytic Ca²⁺ signals play important roles in both seizures and epilepsy, and this review aims to highlight the current knowledge of the roles of this central astrocytic signaling mechanism in ictogenesis and epileptogenesis.

The power of ECG in multimodal patient-specific seizure monitoring: Added value to an EEG-based detector using limited channels

Objective

Wearable seizure detection devices could provide more reliable seizure documentation outside the hospital compared to seizure self‐reporting by patients, which is the current standard. Previously, during the SeizeIT1 project, we studied seizure detection based on behind‐the‐ear electroencephalography (EEG). However, the obtained sensitivities were too low for practical use, because not all seizures are associated with typical ictal EEG patterns. Therefore, in this paper, we aim to develop a multimodal automated seizure detection algorithm integrating behind‐the‐ear EEG and electrocardiography (ECG) for detecting focal seizures. In this framework, we quantified the added value of ECG to behind‐the‐ear EEG.

Methods

This study analyzed three multicenter databases consisting of 135 patients having focal epilepsy and a total of 896 seizures. A patient‐specific multimodal automated seizure detection algorithm was developed using behind‐the‐ear/temporal EEG and single‐lead ECG. The EEG and ECG data were processed separately using machine learning methods. A late integration approach was applied for fusing those predictions.

Results

The multimodal algorithm outperformed the EEG‐based algorithm in two of three databases, with an increase of 11% and 8% in sensitivity for the same false alarm rate.

Significance

ECG can be of added value to an EEG‐based seizure detection algorithm using only behind‐the‐ear/temporal lobe electrodes for patients with focal epilepsy.

Novel Concepts for the Role of Chloride Cotransporters in Refractory Seizures

Epilepsy is associated with a multitude of acquired or genetic neurological disorders characterized by a predisposition to spontaneous recurrent seizures. An estimated 15 million patients worldwide have ongoing seizures despite optimal management and are classified as having refractory epilepsy. Early-life seizures like those caused by perinatal hypoxic ischemic encephalopathy (HIE) remain a clinical challenge because although transient, they are difficult to treat and associated with poor neurological outcomes. Pediatric epilepsy syndromes are consistently associated with intellectual disability and neurocognitive comorbidities. HIE and arterial ischemic stroke are the most common causes of seizures in term neonates and account for 7.5-20% of neonatal seizures. Standard first-line treatments such as phenobarbital (PB) and phenytoin fail to curb seizures in ~50% of neonates. In the long-term, HIE can result in hippocampal sclerosis and temporal lobe epilepsy (TLE), which is the most common adult epilepsy, ~30% of which is associated with refractory seizures. For patients with refractory TLE seizures, a viable option is the surgical resection of the epileptic foci. Novel insights gained from investigating the developmental role of Cl- cotransporter function have helped to elucidate some of the mechanisms underlying the emergence of refractory seizures in both HIE and TLE. KCC2 as the chief Cl- extruder in neurons is critical for enabling strong hyperpolarizing synaptic inhibition in the brain and has been implicated in the pathophysiology underlying both conditions. More recently, KCC2 function has become a novel therapeutic target to combat refractory seizures.

The TAAR1 inhibitor EPPTB suppresses neuronal excitability and seizure activity in mice

Epilepsy is a common neurological disease. G protein-coupled receptors (GPCRs) are extensively distributed and play an important role in human health by serving as therapeutic targets for various diseases. As one of the GPCRs, trace amine-associated receptor 1 (TAAR1) has recently aroused increasing interest as a potential therapeutic target for psychiatric disorders. However, the effect of TAAR1 on epileptic seizures remains unclear. We hypothesized that TAAR1 plays an important role in epilepsy and might represent a potential therapeutic target. In this study, we analyzed a mouse epilepsy model and patients with temporal lobe epilepsy (TLE) and observed substantially increased TAAR1 expression compared with the control group. In recordings of hippocampal slices, the TAAR1-specific inhibitor N-(3-ethoxyphenyl)-4-(pyrrolidin-1-yl)-3-(trifluoromethyl) benzamide (EPPTB) suppressed the excitability of hippocampal pyramidal neurons. EPPTB also reduced seizure-like events (SLEs) and seizure activity. Our results suggest that EPPTB attenuates seizure activity and that TAAR1 might be a potential drug target for individuals with epilepsy.

The association between MDR1 C3435T genetic polymorphism and the risk of multidrug-resistant epilepsy in Egyptian children

Background

Epilepsy is a chronic disease affecting about 2% of the population and is considered a serious neurological disease. Despite its good prognosis, 20–30% of epileptic patients were not cured of their seizures even with the many trials of antiepileptic drug (AED) therapy. The resistance mechanism is still unclear, maybe due to the effect of the genetic factors on the bioavailability of the drugs. Consequently, the association between therapy resistance and the presence of a gene called “multidrug resistance 1 (MDR1)” had been proposed. Thus, the present study aimed to understand the relationship between the genetic polymorphism of MDR1C3435T and the resistance to AEDs.

Result

A non-significant association was found between MDR1 C3435T single-nucleotide polymorphism (SNP) and drug-resistant epilepsy. However, there was statistical significance in the association between the drug type and the genotype distribution, in cases that were maintained on sodium valproate and MDR1C3435T genotype.

Conclusion

Possible involvement of the MDR1 gene C 3435T polymorphism with sodium valproate resistance clarifies the importance of genetic variability in response to the drug and may help to find novel genetic therapy for epilepsy, by targeting the biological mechanisms responsible for epilepsy in each specific individual. Future studies with bigger sample sizes and in other racial populations will be necessary.

Classification with a Deferral Option and Low-Trust Filtering for Automated Seizure Detection

Wearable technology will become available and allow prolonged electroencephalography (EEG) monitoring in the home environment of patients with epilepsy. Neurologists analyse the EEG visually and annotate all seizures, which patients often under-report. Visual analysis of a 24-h EEG recording typically takes one to two hours. Reliable automated seizure detection algorithms will be crucial to reduce this analysis. We investigated such algorithms on a dataset of behind-the-ear EEG measurements. Our first aim was to develop a methodology where part of the data is deferred to a human expert, who performs perfectly, with the goal of obtaining an (almost) perfect detection sensitivity (DS). Prediction confidences are determined by temperature scaling of the classification model outputs and trust scores. A DS of approximately 90% (99%) can be achieved when deferring around 10% (40%) of the data. Perfect DS can be achieved when deferring 50% of the data. Our second contribution demonstrates that a common modelling strategy, where predictions from several short EEG segments are combined to obtain a final prediction, can be improved by filtering out untrustworthy segments with low trust scores. The false detection rate shows a relative decrease between 21% and 43%, and the DS shows a small increase or decrease.

Cortical expression of IL1-β, Bcl-2, Caspase-3 and 9, SEMA-3a, NT-3 and P-glycoprotein as biological markers of intrinsic severity in drug-resistant temporal lobe epilepsy

Mesial temporal lobe epilepsy (mTLE) is the most common epilepsy induced by previous cerebral injury, and one out of three mTLE patients develops drug resistance (DR).

AIM

To assess the expression of Bcl-2, Caspase-3, Caspase-9, IL1-β, SEMA-3a, NT-3 and P-glycoprotein in the temporal cortex and their relationship with the progression of mTLE-DR clinical features in patients with mTLE-DR.

METHOD

Tissue samples from 17 patients were evaluated for protein expression by Western blot and the relationships of the evaluated proteins with the clinical features of the mTLE were assessed through hierarchical cluster analysis.

RESULTS

The mTLE-DR group showed significantly higher P-glycoprotein, Bcl-2 and Caspase-9 levels ***p < 0.0001, ****p < 0.0001 and ***p < 0.0002, respectively, than the autopsy control group. Four patient clusters were identified: Clusters 1 and 3 showed relationships among the age of mTLE onset, duration of mTLE-DR, average number of epileptic seizures per week, number of previous antiepileptic drugs (AEDs) and increased expression of Caspase-3, Caspase-9, Neurotrophin-3 and Semaphorin-3a. Clusters 2 and 4 showed relationships among the mTLE onset age, current age, average number of epileptic seizures per week, number of previous AEDs and increased expression of IL1-β, Bcl-2, P-glycoprotein, Caspase-3 and NT-3.

CONCLUSION

The relationships among the clinical data the age of mTLE onset, DR duration, number of previous AEDs, and average number of seizures per week and the expression of proteins involved in neuronal death, neuroinflammation and aberrant connection formation, as which are biological markers in the cerebral temporal cortex, are important factors in the progression and severity of mTLE-DR and support the intrinsic severity hypothesis.

Assessing the feasibility of detecting epileptic seizures using non-cerebral sensor data

This paper investigates the feasibility of using non-cerebral, time-series data to detect epileptic seizures. Data were recorded from fifteen patients (7 male, 5 female, 3 not noted, mean age 36.17 yrs), five of whom had a total of seven seizures. Patients were monitored in an inpatient setting using standard video-electroencephalography (vEEG), while also wearing sensors monitoring electrocardiography, electrodermal activity, electromyography, accelerometry, and audio signals (vocalizations). A systematic and detailed study was conducted to identify the sensors and the features derived from the non-cerebral sensors that contribute most significantly to separability of data acquired during seizures from non-seizure data. Post-processing of the data using linear discriminant analysis (LDA) shows that seizure data are strongly separable from non-seizure data based on features derived from the signals recorded. The mean area under the receiver operator characteristic (ROC) curve for each individual patient that experienced a seizure during data collection, calculated using LDA, was 0.9682. The features that contribute most significantly to seizure detection differ for each patient. The results show that a multimodal approach to seizure detection using the specified sensor suite is promising in detecting seizures with both sensitivity and specificity. Moreover, the study provides a means to quantify the contribution of each sensor and feature to separability. Development of a non-electroencephalography (EEG) based seizure detection device would give doctors a more accurate seizure count outside of the clinical setting, improving treatment and the quality of life of epilepsy patients.

Cerebellar Degeneration in Epilepsy: A Systematic Review

INTRODUCTION

Cerebellar degeneration has been associated in patients with epilepsy, though the exact pathogenic mechanisms are not understood. The aim of this systematic review was to identify the prevalence of cerebellar degeneration in patients with epilepsy and identify any pathogenic mechanisms.

METHODOLOGY

A systematic computer-based literature search was conducted using the PubMed database. Data extracted included prevalence, clinical, neuroradiological, and neuropathological characteristics of patients with epilepsy and cerebellar degeneration.

RESULTS

We identified three consistent predictors of cerebellar degeneration in the context of epilepsy in our review: temporal lobe epilepsy, poor seizure control, and phenytoin as the treatment modality. Whole brain and hippocampal atrophy were also identified in patients with epilepsy.

CONCLUSIONS

Cerebellar degeneration is prevalent in patients with epilepsy. Further prospective studies are required to confirm if the predictors identified in this review are indeed linked to cerebellar degeneration and to establish the pathogenic mechanisms that result in cerebellar insult.

Real-world hospitalization risk in patients with epilepsy treated with perampanel

AIM

The aim of this study was to evaluate the risk of hospitalization and emergency department admission following initiation of perampanel treatment in patients with epilepsy.

METHODS

This study is a retrospective longitudinal cohort study (Optum® Clinformatics® Datamart). Patients 4 to 11 years of age with a diagnosis of partial onset seizures or ≥12 years of age with primary generalized tonic-clonic seizures who had ≥1 perampanel prescription between 1/1/2014 and 3/31/2018 were eligible for the study. Additionally, patients were required to have 12-months of continuous enrollment before (pre-) and after (post-) the date of the first perampanel prescription (index-date). One-year relative-risks of all-cause and epilepsy-related hospitalizations and emergency department (ED) visits were estimated following initiation of perampanel treatment. Outcomes were also evaluated among a subsets of patients who were adherent to perampanel treatment, defined as a Medication Possession Ratio (MPR) ≥80%.

RESULTS

A total of 320 patients were included in the study, mean age 38.2 ± 19 years, 56.6% female. In the overall population, the relative risks of hospitalizations or ED visits after perampanel initiation were not significantly different. Among the 145 patients who had an MPR ≥80%, initiation of perampanel treatment resulted in a significantly lower risk of epilepsy-related hospitalization (relative risk [RR] = 0.68, confidence interval [CI] [0.47, 0.98]), all-cause ED visits (RR = 0.80, CI [0.66, 0.98]), and epilepsy-related ED visits (RR = 0.74, CI [0.57, 0.95]) in the follow-up period.

CONCLUSIONS

Adherence to perampanel treatment was associated with significant reductions in one-year hospitalizations and ED visit risk in real world settings.

Amygdala Low-Frequency Stimulation Reduces Pathological Phase-Amplitude Coupling in the Pilocarpine Model of Epilepsy

Temporal-lobe epilepsy (TLE) is the most common type of drug-resistant epilepsy and warrants the development of new therapies, such as deep-brain stimulation (DBS). DBS was applied to different brain regions for patients with epilepsy; however, the mechanisms of action are not fully understood. Therefore, we tried to characterize the effect of amygdala DBS on hippocampal electrical activity in the lithium-pilocarpine model in male Wistar rats. After status epilepticus (SE) induction, seizure patterns were determined based on continuous video recordings. Recording electrodes were inserted in the left and right hippocampus and a stimulating electrode in the left basolateral amygdala of both Pilo and age-matched control rats 10 weeks after SE. Daily stimulation protocol consisted of 4 × 50 s stimulation trains (4-Hz, regular interpulse interval) for 10 days. The hippocampal electroencephalogram was analyzed offline: interictal epileptiform discharge (IED) frequency, spectral analysis, and phase-amplitude coupling (PAC) between delta band and higher frequencies were measured. We found that the seizure rate and duration decreased (by 23% and 26.5%) and the decrease in seizure rate correlated negatively with the IED frequency. PAC was elevated in epileptic animals and DBS reduced the pathologically increased PAC and increased the average theta power (25.9% ± 1.1 vs. 30.3% ± 1.1; p < 0.01). Increasing theta power and reducing the PAC could be two possible mechanisms by which DBS may exhibit its antiepileptic effect in TLE; moreover, they could be used to monitor effectiveness of stimulation.

MicroRNA-542-3p Regulates P-glycoprotein Expression in Rat Epilepsy via the Toll-like Receptor 4/Nuclear Factor-kappaB Signaling Pathway

BACKGROUND

The function of microRNA-542-3p (miR-542-3p) in rat epilepsy is still unclear.

METHODS

The levels of miR-542-3p and toll-like receptor 4 (TLR4) were determined through quantitative real-time PCR. The protein levels were examined via the western blot analysis. The relationship between miR-542-3p and TLR4 was confirmed through luciferase assay. Pathological changes were analyzed via Hematoxylin-eosin (HE) and Nissl staining.

RESULTS

The rats and hippocampal cells were treated with kainic acid (KA) in vivo and in vitro. miR-542-3p was low in KA-treated rats, hippocampal cells and cerebrospinal fluid of patients with epilepsy. Further functional analysis showed that miR-542-3p overexpression inhibited KAinduced average seizure frequency, damage of hippocampal neuron and cell apoptosis, leading to the alleviation of the brain injury in epilepsy rats. miR-542-3p was determined to downregulate TLR4 expression. The relationship between miR-542-3p and TLR4 was confirmed. TLR4 knockdown reduced KA-induced nuclear factor-kappa B p65 (NF-κB p65), multidrug resistance 1 (MDR1), P-glycoprotein (P-gp) and apoptosis-associated protein levels. Further, for NF-κB p65, MDR1, P-gp and apoptosis-associated protein levels detection, miR-542-3p mimic showed a suppressive effect on these KA-induced protein levels, whereas TLR4 overexpression ameliorated the miR-542-3p-induced these protein levels in KA-treated epilepsy rats.

CONCLUSION

We identified that miR-542-3p attenuated seizure-induced brain injury and the expression of P-gp in epilepsy rats through inhibiting TLR4/NF-κB signaling pathway, which might contribute to improved epilepsy therapy.

A Novel Approach to Refractory Epilepsy by Targeting Pgp Peripherally and Centrally: Therapeutic Targets and Future Perspectives

Refractory epilepsy is a type of epilepsy involving seizures uncontrolled by first or second- line anticonvulsant drugs at a regular therapeutic dose. Despite considerable growth in epileptic pharmacotherapy, one-third of the patients are resistant to current therapies. In this, the mechanisms responsible for resistant epilepsy are either increased expulsion of antiepileptic drugs (AEDs) by multidrug resistance (MDR) transporters from the epileptogenic tissue or reduced sensitivity of drug in epileptogenic brain tissue. The difficulty to treat refractory epilepsy is because of drug resistance due to cellular drug efflux, use of drug monotherapy, and subtherapeutic dose administration. Increased expression of Pgp is also responsible for resistance epilepsy or refractory epilepsy. Increased glutamate expression via inhibition of cyclooxygenase-II (COX-II) enzyme also upregulate P-glycoprotein (Pgp) expression and augment instance of recurrent seizures. Peripheral and central inhibition of Pgp is a powerful tool to control this drug resistant epilepsy. Drug resistance primarily involves multidrug resistance (MDR1) gene responsible for encoding P-glycoprotein (Pg- P1 or MDR1). Currently, there is no drug under clinical practice which inhibits MDR1. The present review cites some drugs like Calcium Channel Blockers (CCBs), COX-II inhibitors, and glutamate receptors antagonists that inhibit P-gp. The exploitation of these targets may emerge as a beneficial approach for patients with drug-resistant epilepsy. The present review further highlights the mechanistic role of Pgp in drug-resistant epilepsy, glutamate role in drug efflux, and management approach.

P38 Regulates Kainic Acid-Induced Seizure and Neuronal Firing via Kv4.2 Phosphorylation

The subthreshold, transient A-type K⁺ current is a vital regulator of the excitability of neurons throughout the brain. In mammalian hippocampal pyramidal neurons, this current is carried primarily by ion channels comprising Kv4.2 α-subunits. These channels occupy the somatodendritic domains of these principle excitatory neurons and thus regulate membrane voltage relevant to the input-output efficacy of these cells. Owing to their robust control of membrane excitability and ubiquitous expression in the hippocampus, their dysfunction can alter network stability in a manner that manifests in recurrent seizures. Indeed, growing evidence implicates these channels in intractable epilepsies of the temporal lobe, which underscores the importance of determining the molecular mechanisms underlying their regulation and contribution to pathologies. Here, we describe the role of p38 kinase phosphorylation of a C-terminal motif in Kv4.2 in modulating hippocampal neuronal excitability and behavioral seizure strength. Using a combination of biochemical, single-cell electrophysiology, and in vivo seizure techniques, we show that kainic acid-induced seizure induces p38-mediated phosphorylation of Thr607 in Kv4.2 in a time-dependent manner. The pharmacological and genetic disruption of this process reduces neuronal excitability and dampens seizure intensity, illuminating a cellular cascade that may be targeted for therapeutic intervention to mitigate seizure intensity and progression.

Feasibility of focal brain cooling for partial epilepsy with secondary generalization: A computational study. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2020;2020:2532-2535. [PMID: 33018522 DOI: 10.1109/embc44109.2020.9175157] [Citation(s) in RCA: 0] [Impact Index Per Article: 0]

Experiments with animal models of epilepsy have consistently shown that focal cooling of epilepsy-induced brain region reversibly suppresses or terminates epileptic discharge activity. Recently, we formulated a physiologically plausible temperature dependence in a neural mass model that can reproduce the effect of focal cooling on epileptic discharge activity. This can be used to implement a temperature control in an implantable cooling device for thermal neuromodulation of the epileptogenic zone in patients with partial epilepsy when seizure activity is detected. However, there have been no experiments that looked into the effect of focal cooling in animal models of epilepsy with secondary generalization in which the seizure activity spreads from the pathologic region to other regions of the brain. Using the temperature-dependent neural mass model and a physiological coupling model, we show that focal cooling stops the propagation of low-frequency discharge activity; on the other hand, it increases the amount of coupling required to propagate high-frequency discharge activity. Moreover, discharge activities that are propagated with cooling are lower in both magnitude and frequency compared to those propagated without cooling. These results suggest the feasibility of focal cooling as an effective alternative therapeutic treatment for medically intractable partial epilepsy even with secondary generalization.Clinical Relevance- The computational study establishes focal cooling of the brain region with partial epilepsy not only suppresses epileptic discharges but can also prevent its generalization to other brain regions.

Resting-state functional MRI connectivity impact on epilepsy surgery plan and surgical candidacy: prospective clinical work

OBJECTIVE

The authors' goal was to prospectively quantify the impact of resting-state functional MRI (rs-fMRI) on pediatric epilepsy surgery planning.

METHODS

Fifty-one consecutive patients (3 months to 20 years old) with intractable epilepsy underwent rs-fMRI for presurgical evaluation. The team reviewed the following available diagnostic data: video-electroencephalography (n = 51), structural MRI (n = 51), FDG-PET (n = 42), magnetoencephalography (n = 5), and neuropsychological testing (n = 51) results to formulate an initial surgery plan blinded to the rs-fMRI findings. Subsequent to this discussion, the connectivity results were revealed and final recommendations were established. Changes between pre- and post-rs-fMRI treatment plans were determined, and changes in surgery recommendation were compared using McNemar's test.

RESULTS

Resting-state fMRI was successfully performed in 50 (98%) of 51 cases and changed the seizure onset zone localization in 44 (88%) of 50 patients. The connectivity results prompted 6 additional studies, eliminated the ordering of 11 further diagnostic studies, and changed the intracranial monitoring plan in 10 cases. The connectivity results significantly altered surgery planning with the addition of 13 surgeries, but it did not eliminate planned surgeries (p = 0.003). Among the 38 epilepsy surgeries performed, the final surgical approach changed due to rs-fMRI findings in 22 cases (58%), including 8 (28%) of 29 in which extraoperative direct electrical stimulation mapping was averted.

CONCLUSIONS

This study demonstrates the impact of rs-fMRI connectivity results on the decision-making for pediatric epilepsy surgery by providing new information about the location of eloquent cortex and the seizure onset zone. Additionally, connectivity results may increase the proportion of patients considered eligible for surgery while optimizing the need for further testing.

Detection of anomalous high-frequency events in human intracranial EEG

Objective

High‐frequency oscillations (HFOs) are a promising biomarker for the epileptogenic zone. However, no physiological definition of an HFO has been established, so detection relies on the empirical definition of an HFO derived from visual observation. This can bias estimates of HFO features such as amplitude and duration, thereby hindering their utility as biomarkers. Therefore, we set out to develop an algorithm that detects high‐frequency events in the intracranial EEG that are morphologically distinct from background without requiring assumptions about event amplitude or shape.

Method

We propose the anomaly detection algorithm (ADA), which uses unsupervised machine learning to identify segments of data that are distinct from the background. We apply ADA and a standard HFO detector using a root mean square amplitude threshold to intracranial EEG from 11 patients undergoing evaluation for epilepsy surgery. The rate, amplitude, and duration of the detected events and the percent overlap between the two detectors are compared.

Result

In the seizure onset zone (SOZ), ADA detected a subset of conventional HFOs. In non‐SOZ channels, ADA detected at least twice as many events as the standard approach, including some conventional HFOs; however, ADA also identified many low and intermediate amplitude events missed by the standard amplitude‐based method. The rate of ADA events was similar across all channels; however, the amplitude of ADA events was significantly higher in SOZ channels (P < .0045), and the amplitude measurement was more stable over time than the HFO rate, as indicated by a lower coefficient of variation (P < .0125).

Significance

ADA does not require human supervision, parameter optimization, or prior assumptions about event shape, amplitude, or duration. Our results suggest that the algorithm's estimate of event amplitude may differentiate SOZ and non‐SOZ channels. Further studies will examine the utility of HFO amplitude as a biomarker for epilepsy surgical outcome.

Low-frequency Stimulation Decreases Hyperexcitability Through Adenosine A1 Receptors in the Hippocampus of Kindled Rats

INTRODUCTION

In this study, the role of A1 adenosine receptors in improving the effect of Low-Frequency Electrical Stimulation (LFS) on seizure-induced hyperexcitability of hippocampal CA1 pyramidal neurons was investigated.

METHODS

A semi-rapid hippocampal kindling model was used to induce seizures in male Wistar rats. Examination of the electrophysiological properties of CA1 pyramidal neurons of the hippocampus using whole-cell patch-clamp recording 48 h after the last kindling stimulation revealed that the application of LFS as two packages of stimulations at a time interval of 6 h for two consecutive days could significantly restore the excitability CA1 pyramidal neurons evidenced by a decreased in the of the number of evoked action potentials and enhancement of amplitude, maximum rise slope and decay slope of the first evoked action potential, rheobase, utilization time, adaptation index, first-spike latency, and post-AHP amplitude. Selective locked of A1 receptors by the administration of 8-Cyclopentyl-1,3-dimethylxanthine (1 μM, 1 μl, i.c.v.) before applying each LFS package, significantly reduced LFS effectiveness in recovering these parameters.

RESULTS

On the other hand, selective activation of A1 receptors by an injection of N6-cyclohexyladenosine (10 μM, 1 μl, i.c.v.), instead of LFS application, could imitate LFS function in improving these parameters.

CONCLUSION

It is suggested that LFS exerts its efficacy on reducing the neuronal excitability, partially by activating the adenosine system and activating its A1 receptors.

A Spatio-Temporal Model of Seizure Propagation in Focal Epilepsy

We propose a novel Coupled Hidden Markov Model (CHMM) to detect and localize epileptic seizures in clinical multichannel scalp electroencephalography (EEG) recordings. Our model captures the spatio-temporal spread of a seizure by assigning a sequence of latent states (i.e. baseline or seizure) to each EEG channel. The state evolution is coupled between neighboring and contralateral channels to mimic clinically observed spreading patterns. Since the latent state space is exponential, a structured variational algorithm is developed for approximate inference. The model is evaluated on simulated and clinical EEG from two different hospitals. One dataset contains seizure recordings of adult focal epilepsy patients at the Johns Hopkins Hospital; the other contains publicly available non-specified seizure recordings from pediatric patients at Boston Children's Hospital. Our CHMM model outperforms standard machine learning techniques in the focal dataset and achieves comparable performance to the best baseline method in the pediatric dataset. We also demonstrate the ability to track seizures, which is valuable information to localize focal onset zones.

Electrical stimulation of cranial nerves in cognition and disease

The cranial nerves are the pathways through which environmental information (sensation) is directly communicated to the brain, leading to perception, and giving rise to higher cognition. Because cranial nerves determine and modulate brain function, invasive and non-invasive cranial nerve electrical stimulation methods have applications in the clinical, behavioral, and cognitive domains. Among other neuromodulation approaches such as peripheral, transcranial and deep brain stimulation, cranial nerve stimulation is unique in allowing axon pathway-specific engagement of brain circuits, including thalamo-cortical networks. In this review we amalgamate relevant knowledge of 1) cranial nerve anatomy and biophysics; 2) evidence of the modulatory effects of cranial nerves on cognition; 3) clinical and behavioral outcomes of cranial nerve stimulation; and 4) biomarkers of nerve target engagement including physiology, electroencephalography, neuroimaging, and behavioral metrics. Existing non-invasive stimulation methods cannot feasibly activate the axons of only individual cranial nerves. Even with invasive stimulation methods, selective targeting of one nerve fiber type requires nuance since each nerve is composed of functionally distinct axon-types that differentially branch and can anastomose onto other nerves. None-the-less, precisely controlling stimulation parameters can aid in affecting distinct sets of axons, thus supporting specific actions on cognition and behavior. To this end, a rubric for reproducible dose-response stimulation parameters is defined here. Given that afferent cranial nerve axons project directly to the brain, targeting structures (e.g. thalamus, cortex) that are critical nodes in higher order brain networks, potent effects on cognition are plausible. We propose an intervention design framework based on driving cranial nerve pathways in targeted brain circuits, which are in turn linked to specific higher cognitive processes. State-of-the-art current flow models that are used to explain and design cranial-nerve-activating stimulation technology require multi-scale detail that includes: gross anatomy; skull foramina and superficial tissue layers; and precise nerve morphology. Detailed simulations also predict that some non-invasive electrical or magnetic stimulation approaches that do not intend to modulate cranial nerves per se, such as transcranial direct current stimulation (tDCS) and transcranial magnetic stimulation (TMS), may also modulate activity of specific cranial nerves. Much prior cranial nerve stimulation work was conceptually limited to the production of sensory perception, with individual titration of intensity based on the level of perception and tolerability. However, disregarding sensory emulation allows consideration of temporal stimulation patterns (axon recruitment) that modulate the tone of cortical networks independent of sensory cortices, without necessarily titrating perception. For example, leveraging the role of the thalamus as a gatekeeper for information to the cerebral cortex, preventing or enhancing the passage of specific information depending on the behavioral state. We show that properly parameterized computational models at multiple scales are needed to rationally optimize neuromodulation that target sets of cranial nerves, determining which and how specific brain circuitries are modulated, which can in turn influence cognition in a designed manner.

Altered expression of parvalbumin immunoreactivity in rat main olfactory bulb following pilocarpine-induced status epilepticus

Epilepsy is a chronic neurological disease characterized by spontaneous recurrent seizures and caused by various factors and mechanisms. Malfunction of the olfactory bulb is frequently observed in patients with epilepsy. However, the morphological changes in the olfactory bulb during epilepsy-induced neuropathology have not been elucidated. Therefore, in the present study, we investigated the expression of parvalbumin (PV), one of the calcium-binding proteins, and morphological changes in the rat main olfactory bulb (MOB) following pilocarpine-induced status epilepticus (SE). Pilocarpine-induced SE resulted in neuronal degeneration in the external plexiform layer (EPL) and glomerular layer (GL) of the MOB. PV immunoreactivity was observed in the neuronal somas and processes in the EPL and GL of the control group. However, six hours after pilocarpine administration, PV expression was remarkably decreased in the neuronal processes compared to the somas and the average number of PV-positive interneurons was significantly decreased. Three months after pilocarpine treatment, the number of PV-positive interneurons was also significantly decreased compared to the 6 hour group in both layers. In addition, the number of NeuN-positive neurons was also significantly decreased in the EPL and GL following pilocarpine treatment. In double immunofluorescence staining for PV and MAP2, the immunoreactivity for MAP2 around the PV-positive neurons was significantly decreased three months after pilocarpine treatment. Therefore, the present findings suggest that decreases in PV-positive GABAergic interneurons and dendritic density in the MOB induced impaired calcium buffering and reciprocal synaptic transmission. Thus, these alterations may be considered key factors aggravating olfactory function in patients with epilepsy.

Clonazepam add-on therapy for drug-resistant epilepsy

BACKGROUND

This is an updated version of the original Cochrane Review published in 2018, Issue 5. Epilepsy affects over 70 million people worldwide, and nearly a quarter of patients with seizures have drug-resistant epilepsy. People with drug-resistant epilepsy have increased risks of premature death, injuries, psychosocial dysfunction, and a reduced quality of life.

OBJECTIVES

To assess the efficacy and tolerability of clonazepam when used as an add-on therapy for adults and children with drug-resistant focal onset or generalised onset epileptic seizures, when compared with placebo or another antiepileptic agent.

SEARCH METHODS

For the latest update we searched the following databases on 4 June 2019: Cochrane Register of Studies (CRS Web), MEDLINE (Ovid) 1946 to 3 June, 2019. The Cochrane Register of Studies (CRS Web) includes the Cochrane Epilepsy Group Specialized Register, the Cochrane Central Register of Controlled Trials (CENTRAL), and randomised or quasi-randomised, controlled trials from Embase, ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform (ICTRP).

SELECTION CRITERIA

Double-blind randomised controlled studies of add-on clonazepam in people with resistant focal or generalised onset seizures, with a minimum treatment period of eight weeks. The studies could be of parallel or cross-over design.

DATA COLLECTION AND ANALYSIS

Two review authors independently selected studies for inclusion, extracted relevant data, and assessed trial quality. We contacted study authors for additional information.

MAIN RESULTS

We found no double-blind randomised controlled trials which met the inclusion criteria.

AUTHORS' CONCLUSIONS

There is no evidence from double-blind randomised controlled trials for or against the use of clonazepam as an add-on therapy for adults and children with drug-resistant focal or generalised onset epileptic seizures. Since the last version of this review no new studies have been found.

Differential Inhibition of Human Nav1.2 Resurgent and Persistent Sodium Currents by Cannabidiol and GS967

Many epilepsy patients are refractory to conventional antiepileptic drugs. Resurgent and persistent currents can be enhanced by epilepsy mutations in the Nav1.2 channel, but conventional antiepileptic drugs inhibit normal transient currents through these channels, along with aberrant resurgent and persistent currents that are enhanced by Nav1.2 epilepsy mutations. Pharmacotherapies that specifically target aberrant resurgent and/or persistent currents would likely have fewer unwanted side effects and be effective in many patients with refractory epilepsy. This study investigated the effects of cannbidiol (CBD) and GS967 (each at 1 μM) on transient, resurgent, and persistent currents in human embryonic kidney (HEK) cells stably expressing wild-type hNav1.2 channels. We found that CBD preferentially inhibits resurgent currents over transient currents in this paradigm; and that GS967 preferentially inhibits persistent currents over transient currents. Therefore, CBD and GS967 may represent a new class of more targeted and effective antiepileptic drugs.

Epilepsy surgery for refractory seizures: a systematic review and meta-analysis in different complications

Background

Nearly one-third of epilepsy patients are refractory/resistant to medical treatment. Developments made in surgical techniques have significantly increased the effectiveness and safety of these techniques, as such techniques have been demonstrated to improve seizure control/freedom outcomes.

Objectives

The aim of this systematic review and meta-analysis was to evaluate the complications of epilepsy surgery.

Patient and methods

The searches were conducted by three independent researchers to find the relevant studies published from January 1, 2009, until the end of January 6, 2019. For English published statistical studies, all studies conducted on epileptic patients who have undergone epilepsy surgery were included.

Statistical analysis

A meta-analysis was conducted in the STATA14 statistical software.

Results

A total of 6735 patients with epilepsy who had undergone the epilepsy surgery were studied. The overall prevalence of complications was 5%. The prevalence of major and minor complications was 5.4% and 3.2% respectively. The prevalence of complications related to the temporal epilepsy surgery and the extra-temporal epilepsy surgery based on 3 studies was 7.9% and 8.2 % respectively. The frequency of neurological and surgical complications after epilepsy surgery was 4.4% and 4.1% respectively.

Conclusion

The overall rate of complications caused by epilepsy surgery was reasonably low (5%), implying that epilepsy surgery especially temporal lobe resection can be safe preferably when performed by an experienced surgeon.

Visual seizure annotation and automated seizure detection using behind-the-ear electroencephalographic channels

Objective

Seizure diaries kept by patients are unreliable. Automated electroencephalography (EEG)‐based seizure detection systems are a useful support tool to objectively detect and register seizures during long‐term video‐EEG recording. However, this standard full scalp‐EEG recording setup is of limited use outside the hospital, and a discreet, wearable device is needed for capturing seizures in the home setting. We are developing a wearable device that records EEG with behind‐the‐ear electrodes. In this study, we determined whether the recognition of ictal patterns using only behind‐the‐ear EEG channels is possible. Second, an automated seizure detection algorithm was developed using only those behind‐the‐ear EEG channels.

Methods

Fifty‐four patients with a total of 182 seizures, mostly temporal lobe epilepsy (TLE), and 5284 hours of data, were recorded with a standard video‐EEG at University Hospital Leuven. In addition, extra behind‐the‐ear EEG channels were recorded. First, a neurologist was asked to annotate behind‐the‐ear EEG segments containing selected seizure and nonseizure fragments. Second, a data‐driven algorithm was developed using only behind‐the‐ear EEG. This algorithm was trained using data from other patients (patient‐independent model) or from the same patient (patient‐specific model).

Results

The visual recognition study resulted in 65.7% sensitivity and 94.4% specificity. By using those seizure annotations, the automated algorithm obtained 64.1% sensitivity and 2.8 false‐positive detections (FPs)/24 hours with the patient‐independent model. The patient‐specific model achieved 69.1% sensitivity and 0.49 FPs/24 hours.

Significance

Visual recognition of ictal EEG patterns using only behind‐the‐ear EEG is possible in a significant number of patients with TLE. A patient‐specific seizure detection algorithm using only behind‐the‐ear EEG was able to detect more seizures automatically than what patients typically report, with 0.49 FPs/24 hours. We conclude that a large number of refractory TLE patients can benefit from using this device.

Apoptotic Markers Are Increased in Epilepsy Patients: A Relation with Manganese Superoxide Dismutase Ala16Val Polymorphism and Seizure Type through IL-1β and IL-6 Pathways

The MnSOD Ala16Val single nucleotide polymorphism (SNP) has been associated with different diseases. However, there are scarcely studies relating this SNP in epilepsy, a neurologic disease that involves some interacting pathways, such as apoptotic and inflammatory factors. In this sense, we decided to investigate the relationship of MnSOD Ala16Val SNP with apoptotic markers in epilepsy and its relation with inflammatory pathway and seizure type. Ninety subjects were evaluated (47 epilepsies; 43 controls) by questionnaires and laboratorial exams. We observed a higher percentage of VV genotype in the epilepsy group when compared to the control group. IL-1β, IL-6, caspase-1, and caspase-3 levels were increased in the epilepsy group (VV genotype). Furthermore, an important correlation between IL-1β vs. caspase-1 and IL-6 vs. caspase-3 was observed in the epilepsy group (VV genotype). The epilepsy group which presented generalized seizures also demonstrated a positive correlation between IL-1β vs. CASP1 and IL-6 vs. CASP3. Thus, it is a plausible propose that epilepsy patients with VV genotype and generalized seizures present a worse inflammatory and apoptotic status. Our findings suggest that the knowledge of MnSOD Ala16Val polymorphism existence is important to evaluate molecular mechanisms associated to seizure and improve the treatment of these patients.

Observational multicentre study into the use of antiepileptic drugs in Spanish neurology consultations

INTRODUCTION

The study aims to quantify the types of antiepileptic drugs (AED) prescribed in neurology consultations.

MATERIAL AND METHOD

This descriptive, observational study included a sample of 559 patients older than 14 years, diagnosed with epilepsy, and receiving pharmacological treatment. Data were collected at outpatient consultations by 47 Spanish neurologists in May 2016. Epilepsy was defined based on the International League Against Epilepsy classification. According to the year of marketing, AEDs were categorised as classic (before 1990) or new (after 1990). We performed a descriptive analysis of qualitative and quantitative variables.

RESULTS

Female patients accounted for 54.6% of the sample. Mean age was 42.7 years; mean age of onset was 22.4. Regarding epilepsy type, 75.7% of patients experienced partial seizures, 51.5% were symptomatic,32.4% had refractory epilepsy, 35.6% had been seizure-free for the previous year, and 59.2% had associated comorbidities.A total of 1103 AED prescriptions were made; 64.6% of prescriptions were for new AEDs; 85.4% of patients received new AEDs. Patients received a mean of 2 AEDs (range, 1-5). A total of 59.6% of patients received polytherapy.The most frequently prescribed AEDs were levetiracetam (42.6%), valproic acid (25.4%), lamotrigine (19.5%), carbamazepine (17.9%), and lacosamide (17.5%). No AED was employed exclusively as monotherapy. The most frequently prescribed AEDs for generalised and partial seizures were valproic acid (48.2%) and levetiracetam (43.2%), respectively. Valproic acid was less frequently prescribed to female patients. Patients with refractory epilepsy or with associated comorbidities were more frequently prescribed a combination of new and classic AEDs (48.7% and 45.6%, respectively) than only one type of AED.

CONCLUSIONS

The majority of patients received new AEDs. The combination of classic and new AEDs was more frequently prescribed to patients with refractory epilepsy or with associated comorbidities.

Improved irritability, mood, and quality of life following introduction of perampanel as late adjunctive treatment for epilepsy

OBJECTIVE

The objective of this study was to evaluate the efficacy and tolerability of perampanel (PER) in late adjunctive treatment of focal epilepsy. We assessed outcomes 1) according to patients' clinical profiles and the broad mechanism of action (MoA) of concomitant antiepileptic drugs (AEDs) and 2) the effects of PER on adverse events, irritability, mood, and quality of life (QOL).

METHODS

Consecutive patients commenced on PER at two epilepsy centers in Melbourne, Australia were identified. A nested cohort underwent detailed prospective assessment, while the remainder were retrospectively analyzed. Six- and 12-month efficacy endpoints were at least a 50% reduction in seizure frequency (responders) and complete seizure freedom. The prospective cohort underwent standardized validated questionnaires at 0, 1, 3, 6, and 12 months using the modified semi-structured seizure interview (SSI), Liverpool Adverse Events Profile (LAEP), Quality of Life in Epilepsy-Patient-Weighted (QOLIE-10-P), Neurological Disorders Depression Inventory Epilepsy (NDDI-E), and an Irritability Questionnaire.

RESULTS

One hundred sixty patients were followed for a median of 6 months: the mean number of prior AEDs was 6, 99% had drug-resistant epilepsy, and 72% had never experienced a prior seizure-free period of at least 6 months (=continuously refractory epilepsy). Perampanel was associated with responder and seizure freedom rates of 30.6% and 9.4% at 6 months and 19.4% and 4.4% (5.6% adjusted for the titration period) at 12 months. Having "continuously refractory epilepsy" was associated with a reduced likelihood of seizure freedom at 6 months (5% vs. 30%; p = 0.001) and 12 months (3% vs. 13%; p = 0.058). Quality of Life in Epilepsy-Patient-Weighted, irritability, and NDDI-E showed mean improvement at 6 months from baseline.

SIGNIFICANCE

Even when used as late add-on adjunctive therapy in patients with highly refractory focal epilepsy, PER can result in 12-month seizure freedom of 5.6%. The likelihood of seizure freedom was associated with prior "continuous medication refractoriness". Six months after introduction of PER patients reported improved mood, QOL, and decreased irritability.

Personalizing Heart Rate-Based Seizure Detection Using Supervised SVM Transfer Learning

Objective: Automated seizure detection is a key aspect of wearable seizure warning systems. As a result, the quality of life of refractory epilepsy patients could be improved. Most state-of-the-art algorithms for heart rate-based seizure detection use a so-called patient-independent approach, which do not take into account patient-specific data during algorithm training. Although such systems are easy to use in practice, they lead to many false detections as the ictal heart rate changes are patient-dependent. In practice, only a limited amount of accurately annotated patient data is typically available, which makes it difficult to create fully patient-specific algorithms.

Methods: In this context, this study proposes for the first time a new transfer learning approach that allows to personalize heart rate-based seizure detection by using only a couple of days of data per patient. The algorithm was evaluated on 2,172 h of single-lead ECG data from 24 temporal lobe epilepsy patients including 227 focal impaired awareness seizures.

Results: The proposed personalized approach resulted in an overall sensitivity of 71% with 1.9 false detections per hour. This is an average decrease in false detection rate of 37% compared to the reference patient-independent algorithm using only a limited amount of personal seizure data. The proposed transfer learning approach adapts faster and more robustly to patient-specific characteristics than other alternatives for personalization in the literature.

Conclusion: The proposed method allows an easy implementable solution to personalize heart rate-based seizure detection, which can improve the quality of life of refractory epilepsy patients when used as part of a multimodal seizure detection system.

Safety and Efficacy of Brivaracetam in Pediatric Refractory Epilepsy: A Single-Center Clinical Experience

Brivaracetam is a new antiepileptic drug with limited data in children. The objective of this study was to assess the efficacy/tolerability of brivaracetam. This is a retrospective chart review of children/adolescents with refractory epilepsy treated with brivaracetam from 2016 to 2018. The primary outcome was seizure reduction (decrease in seizure frequency >50%). Twenty-three patients were identified. Mean age at initiation was 12.5 years. Fourteen were females. Epilepsy was focal in 11, generalized in 6, and mixed in 3. Average dose was 3.9 mg/kg/d. The mean duration of treatment was 8.2 months. Eight had greater than 50% decrease in seizure frequency, of which 7 had focal epilepsy, and 1 had Lennox-Gastaut/mixed epilepsy. Two had drowsiness and 3 behavioral complaints. One experienced tingling and dizziness. Our retrospective review suggests that brivaracetam is an effective therapy for refractory focal epilepsy in children older than 4 years of age.

Knowledge of and attitudes toward epilepsy surgery among neurologists in Saudi Arabia

Objectives:

To investigate the levels of knowledge and attitudes toward epilepsy surgery among neurologists in Saudi Arabia and evaluate the factors that affect the physicians’ knowledge and attitudes.

Methods:

A quantitative observational cross-sectional study conducted at King Saud University Medical City, Riyadh. The data were collected using a newly developed, self-administered online questionnaire. The questionnaire contained 3 sections: demographic information, knowledge, and attitudes which then sent to neurologist in Saudi Arabia from December 2016 to March 2017.

Results:

A total of 106 neurologists met our inclusion criteria. Eighty percent of the participants had at least one epilepsy center in their city, and 78% indicated that they had access to adequate expertise and resources to enable the appropriate selection of epilepsy surgical candidates. Only 57.5% of the neurologists had a sufficient level of knowledge regarding epilepsy surgery. Neurologists with higher level of knowledge referred more patients to EMU and discussed epilepsy surgery more often with their patients. Overall, more than half of the neurologists (52.8%) had a positive attitude toward epilepsy surgery. There was a significantly positive correlation between the scores of knowledge and attitude (p<0.001).

Conclusion:

Neurologists in Saudi Arabia appear to have moderate knowledge of and positive attitudes toward epilepsy surgery. The place of the last neurology certificate, type of practicing hospital, and access to expertise and resources, affected their knowledge. Adequate knowledge was positively correlated with attitude.

Neuroprotective effects and improvement of learning and memory elicited by erythravine and 11α-hydroxy-erythravine against the pilocarpine model of epilepsy

Deficits in cognitive functions are often observed in epileptic patients, particularly in temporal lobe epilepsy (TLE). Evidence suggests that this cognitive decline can be associated with the occurrence of focal brain lesions, especially on hippocampus and cortex regions. We previously demonstrated that the erythrinian alkaloids, (+)-erythravine and (+)-11α-hydroxy-erythravine, inhibit seizures evoked in rats by different chemoconvulsants.

AIMS

The current study evaluated if these alkaloids would be acting in a neuroprotective way, reducing hippocampal sclerosis, and consequently, improving learning/memory performance.

MAIN METHODS

Here we confirmed the anticonvulsant effect of both alkaloids by means of the pilocarpine seizure-induced model and also showed that they enhanced spatial learning of rats submitted to the Morris Water Maze test reverting the cognition deficit. Additionally, immunohistochemistry assays showed that neuronal death and glial activation were prevented by the alkaloids in the hippocampus CA1, CA3 and dentate gyrus regions at both hemispheres indistinctly 15 days after status epilepticus induction.

KEY FINDINGS

Our results show, for the first-time, the improvement on memory/learning elicited by these erythrinian alkaloids. Furthermore, data presented herein explain, at least partially, the cellular mechanism of action of these alkaloids. Together, (+)-erythravine and (+)-11α-hydroxy-erythravine seem to be a promising protective strategy against TLE, comprising three main aspects: neuroprotection, control of epileptic seizures and cognitive improvement.

SIGNIFICANCE

Moreover, our findings on neuroprotection corroborate the view that seizure frequency and severity, hippocampal lesions and memory deficits are interconnected events.

Identification of Risk Factors for Refractory Status Epilepticus

Objective: The objective of this study is to identify risk factors for the development of refractory status epilepticus (RSE). Methods: This was an IRB-approved, retrospective case control study that included patients admitted with status epilepticus between August 1, 2014, and July 31, 2017. Cases were defined as those with RSE, and controls were those who did not develop RSE. A bivariate analysis was conducted comparing those with RSE and those without RSE. A stepwise logistic regression model was constructed predicting for progression to RSE. Risk factors for progression to RSE were extrapolated from this model. Results: A total of 184 patients met inclusion criteria for the study (99 controls and 49 cases). After adjusting for covariates in the logistic regression, patients with convulsive seizures had a lower odds of developing RSE (odds ratio [OR] = 0.375; 95% CI = 0.148 to 0.951; P = 0.0388). Treatment with benzodiazepines plus levetiracetam had a higher odds of developing RSE (OR = 3.804; 95% CI = 1.523 to 9.499; P = 0.0042). Conclusion and Relevance: This study found that patients with convulsive seizures had a lower odds of developing RSE. In addition, patients treated with benzodiazepines and levetiracetam had a higher odds of developing RSE. This information can be used to potentially identify patients at higher risk of developing RSE, so that treatment can be modified to reduce morbidity and mortality. These results may warrant further investigation into the effectiveness of levetiracetam as a first-line agent for the treatment of SE.

Lesion Network Localization of Seizure Freedom following MR-guided Laser Interstitial Thermal Ablation

Treatment-resistant epilepsy is a common and debilitating neurological condition, for which neurosurgical cure is possible. Despite undergoing nearly identical ablation procedures however, individuals with treatment-resistant epilepsy frequently exhibit heterogeneous outcomes. We hypothesized that treatment response may be related to the brain regions to which MR-guided laser ablation volumes are functionally connected. To test this, we mapped the resting-state functional connectivity of surgical ablations that either resulted in seizure freedom (N = 11) or did not result in seizure freedom (N = 16) in over 1,000 normative connectomes. There was no difference seizure outcome with respect to the anatomical location of the ablations, and very little overlap between ablation areas was identified using the Dice Index. Ablations that did not result in seizure-freedom were preferentially connected to a number of cortical and subcortical regions, as well as multiple canonical resting-state networks. In contrast, ablations that led to seizure-freedom were more functionally connected to prefrontal cortices. Here, we demonstrate that underlying normative neural circuitry may in part explain heterogenous outcomes following ablation procedures in different brain regions. These findings may ultimately inform target selection for ablative epilepsy surgery based on normative intrinsic connectivity of the targeted volume.

ABCB1 Polymorphisms and Drug-Resistant Epilepsy in a Tunisian Population

Background

Epilepsy is one of the most common neurological disorders with about 30% treatment failure rate. An interindividual variations in efficacy of antiepileptic drugs (AEDs) make the treatment of epilepsy challenging, which can be attributed to genetic factors such as ATP-Binding Cassette sub-family B, member1 (ABCB1) gene polymorphisms.

Objective

The main objective of the present study is to evaluate the association of ABCB1 C1236T, G2677T, and C3435T polymorphisms with treatment response among Tunisian epileptic patients.

Materials and Methods

One hundred epileptic patients, originated from north of Tunisia, were recruited and categorized into 50 drug-resistant and 50 drug-responsive patients treated with antiepileptic drugs (AEDs) as per the International League Against Epilepsy. DNA of patients was extracted and ABCB1 gene polymorphisms studied using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) method.

Results

The C1236T, G2677T, and C3435T polymorphisms were involved into AED resistance. Significant genotypic (C1236T TT (p ≤ 0.001); G2677T TT (p = 0.001); C3435T TT (p ≤ 0.001)) and allelic associations (C1236T T (3.650, p ≤ 0.001); G2677TT (1.801, p = 0.044); C3435T T (4.730, p ≤ 0.001)) with drug resistance epilepsy (DRE) were observed. A significant level of linkage disequilibrium (LD) was also noted between ABCB1 polymorphisms. Patients with the haplotypes CT and TT (C1236T-G2677T); GT, TC, and TT (G2677T-C3435T); CT and TT (C1236T-C3435T); CTT, TTC, TGT, and TTT (C1236T-G2677T-C3435T) were also significantly associated to AED resistance.

Conclusions

The response to antiepileptics seems to be modulated by TT genotypes, T alleles, and the predicted haplotypes for the tested SNPs in our population. Genetic analysis is a valuable tool for predicting treatment response and thus will contribute to personalized medicine for Tunisian epileptic patients.