A retrospective study of the efficacy of zonisamide in controlling seizures in 57 cats

BACKGROUND

Evidence-based recommendations for antiepileptic drug selection in cats beyond phenobarbital are limited, and additional studies are needed for cats where seizures remain inadequately controlled by administration of phenobarbital alone or for cats that cannot safely receive phenobarbital.

OBJECTIVE

To compare seizure frequency in cats before and after oral administration of zonisamide and describe adverse clinical or clinicopathologic effects in this cohort.

ANIMALS

Fifty-seven cats with a history of seizures.

METHODS

Multicenter, retrospective study. Median number of seizures per month and number of seizure days per month were compared before and after administration of zonisamide in all cats, a subgroup of cats with idiopathic epilepsy (IE), and a subgroup of cats receiving zonisamide as sole therapy. Clinical and clinicopathologic adverse effect data were also reported.

RESULTS

A median decrease of 1 (P = .001, 95% confidence interval (CI) [-1.0, -0.5]) seizure per month, and 1 (P = .003, 95% CI [-1.5, -0.2]) seizure days per month was found across all cats after oral administration of zonisamide. The subgroup with IE showed median decreases of 1 (P = .03, 95% CI [-2.0, -0.5]) and 2 (P = .01, 95% CI [-2.5, -1.0]), respectively. The most common clinical adverse effects were sedation (17%), ataxia (11%), hyporexia (17%), and emesis (5%). One cat developed mild nonregenerative anemia, 2 cats developed mild metabolic acidosis, and 6 cats showed mild increases in ALT and ALP.

CONCLUSION

Zonisamide was well tolerated and efficacious in controlling seizure activity in most cats.

Outcome of psychogenic non-epileptic seizures following diagnosis in the epilepsy monitoring unit

Objective

To study the outcome of patients with psychogenic non-epileptic seizures (PNES) after their diagnosis in the epilepsy monitoring unit (EMU).

Methods

Patients diagnosed in our EMU with definite PNES between January 2009 and May 2023 were contacted by phone, and those who agreed to participate were asked a set of predetermined questions. Comparative analyses were carried out on several variables before and after diagnosis: number of participants with daily PNES, number of visits to the emergency department, number of participants who consulted their general practitioner or a neurologist outside of a scheduled follow-up, number of participants who took antiseizure medications (ASMs) or psychotropic drugs, and employment status.

Results

Out of the 103 patients with a definite diagnosis of PNES, 61 patients (79% female) accepted to participate in our study. The median age at PNES onset was 35 years, and the median delay to diagnosis was 3 years. Almost two-thirds (62%) were receiving ASMs and 40% psychotropic drugs. The mean stay at the EMU was 5 days. PNES diagnosis was explained to almost all patients (97%) by the end of their EMU stay and was well-accepted by most (89%). When contacted, 46% of participants no longer had PNES; 32% mentioned that their PNES had ceased immediately upon communication of the diagnosis. The median follow-up duration was 51 months. Fewer patients had daily seizures after the diagnosis (18 vs. 38%; p < 0.0455). Similarly, the median number of emergency department visits was significantly lower (0 vs. 2; p < 0.001). Only 17 patients consulted their general practitioner (vs. 40, p < 0.001) and 20 a neurologist (vs. 55, p < 0.001) after a PNES attack outside of a scheduled follow-up. The use of ASMs was also significantly reduced from 70 to 33% (p < 0.01), with only one still taking an ASM for its antiseizure properties. Significantly more participants were working at last follow-up than at PNES diagnosis (49 vs. 25%; p < 0.001).

Conclusion

Our study revealed a relatively favorable long-term outcome of definite PNES diagnosed in the EMU that translated in significant reductions in PNES frequency, health care utilization and ASM use, as well as a significant increase in employment rate.

Of Mice and Men: The Inter-individual Variability of the Brain's Response to Drugs

Biological variation is ubiquitous in nature. Despite highly standardized breeding and husbandry under controlled environmental conditions, phenotypic diversity exists in laboratory mice and rats just as it does in humans. The resulting inter-individual variability affects various characteristics of animal disease models, including the responsiveness to drugs. Thus, the common practice of averaging data within an experimental group can lead to misinterpretations in neuroscience and other research fields. In this commentary, the impact of inter-individual variation in drug responsiveness is illustrated by examples from the testing of antiseizure medications in rodent temporal lobe epilepsy models. Individual mice and rats rendered epileptic by treatment according to standardized protocols fall into groups that either do or do not respond to antiseizure medications, thus mimicking the clinical situation in patients with epilepsy. Population responses are not normally distributed, and divergent responding is concealed in averages subjected to parametric statistical tests. Genetic, epigenetic, and environmental factors are believed to contribute to inter-individual variation in drug response but the specific molecular and physiological causes are not well understood. Being aware of inter-individual variability in rodents allows an improved interpretation of both behavioral phenotypes and drug effects in a pharmacological experiment.

Does Initiation of Prophylactic Antiseizure Medication Improve Neurological Outcomes in Patients With Acute Intracerebral Hemorrhage?: A Critically Appraised Topic

OBJECTIVE

The objective of this study was to critically assess current evidence regarding the role of prophylactic antiseizure medication in patients presenting with acute intracerebral hemorrhage (ICH).

METHODS

The objective was addressed through the development of a structured critically appraised topic. This included a clinical scenario with a clinical question, literature search strategy, critical appraisal, results, evidence summary, commentary, and bottom-line conclusions. Participants included resident neurologists, a medical librarian, and content experts in the fields of epilepsy, stroke neurology, neurohospitalist medicine, and neurocritical care.

RESULTS

A randomized clinical trial was selected for critical appraisal. The trial assessed whether prophylactic levetiracetam (LEV) use reduced the risk of acute seizures in patients with ICH, as defined by clinical or electrographic seizure, captured by continuous electroencephalogram 72 hours after enrollment. A total of 42 patients were included in the final analysis (19 in the LEV group and 23 in the placebo group). There was a significantly higher occurrence of seizures in the placebo versus LEV group (LEV 16% vs placebo 43%, P = 0.043). There were no differences in functional outcomes between the groups at 3, 6, or 12 months (P > 0.1).

CONCLUSIONS

The role of prophylactic treatment with antiseizure medication in ICH remains unclear.

Long-term outcomes in refractory status epilepticus

INTRODUCTION

Refractory status epilepticus (RSE) is a diagnosis that can be made when tonic-clonic status epilepticus (SE) and focal SE cannot be stopped by at least two anti-seizure medications after 30 and 60 minutes, respectively, from the time of commencement. It could result in mortality, loss of functionality, neurological deficiency, and other serious short- and long-term effects.

AREAS COVERED

This narrative review covers original clinical studies of any design and case series investigating long-term outcomes of RSE recorded after at least a year from the SE onset.

EXPERT OPINION

The future of a patient with RSE rests mostly on the long-term effects of this severe pathological condition, which may be accompanied with systemic complications like hyperthermia, hyperkalemia, acidosis, and/or stress cardiomyopathy. Younger patients with less severe RSE of shorter duration, particularly of the convulsive kind, are reported to have better long-term outcomes. Previous studies on the factors influencing the long-term outcomes of RSE, however, did not link the outcomes to treatment options for the condition. Such circumstances currently prevent making any definitive recommendations on the treatment of RSE until future research with adequate statistical power is completed.

Clinico-Etiologic Profile of Children and Adolescents with Drug-Resistant Epilepsy in a low-Resource Setting: 10 Years' Experience

Purpose: Nearly 25% to 30% of children with epilepsy develop drug-resistant epilepsy. Etiology of epilepsy, including drug-resistant epilepsy, varies with geographical region. Identifying paucity of etiologic data on drug-resistant epilepsy from our region and similar low-resource settings, we aimed to describe the clinical and etiologic profile of children and adolescents with drug-resistant epilepsy, to better inform region-specific concerns. Methods: A chart-based retrospective review covering 10 years (January 2011-December 2020) was conducted. Participants between 1 months and 18 years of age who fulfilled International League Against Epilepsy (ILAE) definition of drug-resistant epilepsy were enrolled. Clinical details, perinatal history, electroencephalography (EEG), magnetic resonance imaging (MRI), and other evaluation-based data were analyzed. Results: Five hundred ninety-three children (52.3% males) were enrolled. The median age at presentation was 63 (interquartile range [IQR] 12-72) months and median age at onset was 12 (IQR 2-18) months. The most frequent seizure type was generalized (76.6%). Of these, epileptic spasms (48.1%) were most frequent. Focal seizures comprised 22.9%. The predominant contributor to etiology was perinatal adverse events, including perinatal asphyxia (37.9%), neonatal hypoglycemic brain injury (15.6%), and neonatal sepsis/meningitis. Electroclinical syndromes were observed in 361 (60.9%) children. Of these, the most frequent were West syndrome (48%) and Lennox-Gastaut syndrome (6.2%). Conclusion: Perinatal brain injury and brain infections were the most common causes of drug-resistant epilepsy identified. These findings indicate an opportunity for reducing the burden of pediatric drug-resistant epilepsy in our region by instituting preventive measures, including improved perinatal care, promotion of institutional deliveries, optimized obstetric and neonatal care, and immunization for vaccine-preventable infections such as bacterial meningitis and Japanese B encephalitis.

In Vivo and In Vitro Characterization of Close Analogs of Compound KA-11, a New Antiseizure Drug Candidate

Epilepsy is a neurological disorder involving a number of disease syndromes with a complex etiology. A properly matched antiseizure drug (ASD) gives remission in up to 70% of patients. Nevertheless, there is still a group of about 30% of patients suffering from drug-resistant epilepsy. Consequently, the development of new more effective and/or safer ASDs is still an unmet clinical need. Thus, our current studies were focused on the structural optimization/modifications of one of the leading compounds, KA-11, aiming at the improvement of its antiseizure activity. As a result, we designed and synthesized two close analogs with highly pronounced drug-like physicochemical properties according to in silico predictions, namely KA-228 and KA-232, which were subsequently tested in a panel of animal seizure models, i.e., MES, 6 Hz (32 mA), scPTZ and ivPTZ. Among these compounds, KA-232, which was designed as a water-soluble salt, was distinctly more effective than KA-228 and assured similar antiseizure protection as its chemical prototype KA-11. With the aim of a more detailed characterization of both new molecules, in vitro binding tests were performed to evaluate the potential mechanisms of action. Furthermore, KA-232 was also evaluated in several ADME-Tox studies, and the results obtained strongly supported its drug-like potential. The proposed chemical modification of KA-11 enabled the identification of new pharmacologically active chemotypes, particularly water-soluble KA-232, which, despite the lack of better efficacy than the leading compound, may be used as a chemical prototype for the development of new ASDs, as well as substances potentially active in other neurological or neurodegenerative conditions.

Caregivers' Perspectives on the Impact of Cannabidiol (CBD) Treatment for Dravet and Lennox-Gastaut Syndromes: A Multinational Qualitative Study

OBJECTIVE

To increase understanding of the impact of cannabidiol (CBD) on outcomes beyond seizure control among individuals with Dravet syndrome or Lennox-Gastaut syndrome.

METHODS

Qualitative interviews were conducted with caregivers of individuals with Dravet syndrome or Lennox-Gastaut syndrome treated with plant-derived, highly purified CBD medicine (Epidiolex in the USA; Epidyolex in Europe; 100 mg/mL oral solution). Symptoms and impacts of Dravet syndrome and Lennox-Gastaut syndrome on individuals were explored, as were the effects of CBD. Data were analyzed using thematic analysis.

RESULTS

Twenty-one caregivers of individuals with Dravet syndrome (n = 14) and Lennox-Gastaut syndrome (n = 7) aged 4-22 years participated. Health-related quality of life improvements associated with CBD included cognitive function, communication, behavior, mobility, and participation in daily activities. Seizure frequency reduction was commonly reported (n = 12), resulting in caregivers having greater freedom and family life being less disrupted. Adverse events were reported by 10 caregivers.

CONCLUSION

In addition to reduced seizure frequency, CBD may have a wide range of beneficial effects beyond seizure control that warrant further investigation.

A Standardized, 3-Tiered, Seizure Burden-Based Protocol for the Treatment of Neonatal Seizures

OBJECTIVE

To evaluate use of a standardized, 3-tiered, seizure burden-based protocol for treatment of all electroencephalography (EEG)-confirmed seizures in a level IV neonatal intensive care unit (NICU).

STUDY DESIGN

All infants admitted to the NICU with EEG-confirmed seizures over a 25-month period were enrolled in the study. We compared short-term outcomes before and after implementation of a standardized, 3-tiered protocol.

RESULTS

A total of 107 infants were enrolled in the study. Use of midazolam infusions was reduced by 53.7% (p = 0.02). Midazolam infusion duration increased from 4 to 7.5 days (p = 0.003); however, when excluding 3 outliers, there was no significant difference between groups (-p = 0.67). Duration of EEG monitoring decreased from 5 to 3 days (p = 0.005). Hospital length of stay was unchanged.

CONCLUSION

Implementation of a standardized, 3-tiered protocol for treatment of neonatal seizures improved short-term outcomes. Although not measured directly, reductions in EEG duration and midazolam use are promising indicators of overall seizure burden. More research is needed to evaluate impact on long-term neurodevelopmental outcomes.

Animal models and human tissue compared to better understand and treat the epilepsies

Animal models of human brain disorders permit researchers to explore disease mechanisms and to test potential therapies. However, therapeutic molecules derived from animal models often translate poorly to the clinic. Although human data may be more relevant, experiments on patients are constrained, and living tissue is unavailable for many disorders. Here, we compare work on animal models and on human tissue for three epileptic syndromes where human tissue is excised therapeutically: (1) acquired temporal lobe epilepsies, (2) inherited epilepsies associated with cortical malformations, and (3) peritumoral epilepsies. Animal models rest on assumed equivalencies between human brains and brains of mice, the most frequently used model animal. We ask how differences between mouse and human brains could influence models. General principles and compromises in model construction and validation are examined for a range of neurological diseases. Models may be judged on how well they predict novel therapeutic molecules or new mechanisms. The efficacy and safety of new molecules are evaluated in clinical trials. We judge new mechanisms by comparing data from work on animal models with data from work on patient tissue. In conclusion, we stress the need to cross-verify findings from animal models and from living human tissue to avoid the assumption that mechanisms are identical.

Fighting Epilepsy with Nanomedicines-Is This the Right Weapon?

Epilepsy is a chronic and complex condition and is one of the most common neurological diseases, affecting about 50 million people worldwide. Pharmacological therapy has been, and is likely to remain, the main treatment approach for this disease. Although a large number of new antiseizure drugs (ASDs) has been introduced into the market in the last few years, many patients suffer from uncontrolled seizures, demanding the development of more effective therapies. Nanomedicines have emerged as a promising approach to deliver drugs to the brain, potentiating their therapeutic index. Moreover, nanomedicine has applied the knowledge of nanoscience, not only in disease treatment but also in prevention and diagnosis. In the current review, the general features and therapeutic management of epilepsy will be addressed, as well as the main barriers to overcome to obtain better antiseizure therapies. Furthermore, the role of nanomedicines as a valuable tool to selectively deliver drugs will be discussed, considering the ability of nanocarriers to deal with the less favourable physical-chemical properties of some ASDs, enhance their brain penetration, reduce the adverse effects, and circumvent the concerning drug resistance.

Dispensary Cannabidiol (CBD): Nothing to Worry About!

Introduction: Despite US FDA approval of cannabidiol (CBD) liquid (Epidiolex®), patients with epilepsy still supplement prescription treatments with dispensary CBD. This study aimed to evaluate therapeutic effectiveness of dispensary CBD. Methods: We retrospectively collected dosage information, CBD serum levels, efficacy, and adverse effects from patient charts (children, adolescents, adults) (n = 18). Results: All 18 patients showed no clinical benefit from dispensary CBD as detectable serum levels never reached a therapeutic range of 150 ng/mL (6 patients had barely detectable levels that were below laboratory reporting thresholds). Minute levels of tetrahydrocannabinol (THC) were found in 3 patients, and moderate levels were found in 1 patient. Conclusion: Dispensary CBD failed to reach effective therapeutic levels in all of these patients. The presence of THC demonstrates the current lack of regulation of dispensary CBD. Anecdotal reports of clinical effectiveness should be considered an effect of concomitant prescription antiseizure medications and not dispensary CBD.

Putting the Brakes on Accelerated Cognitive Decline in Alzheimer's Disease with Epileptic Activity

Epileptic activity is known to exacerbate Alzheimer's disease (AD) pathology and worsen disease course. However, few studies have assessed whether treating epileptic activity with antiseizure drugs (ASDs) can improve patient outcomes. The current study by Hautecloque-Raysz et al. shows that patients with prodromal AD and epilepsy (epAD) fare well with ASD treatment, achieving seizure control in a large majority of cases using low dosage ASDs in monotherapy. Compared to slowly progressing AD patients without epilepsy, treated epAD patients experienced a similarly slow cognitive decline. These results suggest that ASDs that suppress seizures can improve outcomes in AD patients with epileptic activity.

Neurocysticercosis in non-endemic regions: The experience of Qatar

Objective

To describe the occurrence and features of Neurocystircercosis (NCC) in Qatar.

Background

Qatar has a mixed population of natives and expats. NCC is not endemic to the region, but clinical practice suggests its occurrence in large numbers.

Design/ methods

A database was created to summarize information retrospectively collected on patients with NCC seen through the national health system (HMC) between 2013 and 2018. We identified demographic and disease related variables (clinical manifestations, investigative findings, treatment and outcome) for all patients.

Results

Out of 420 identified NCC patients, 393 (93.6%) were men, and 98.3% were immigrants from NCC endemic countries such as Nepal (63.8%) and India (29.5%). Eighty percent of patients presented with seizures, with the majority (69%) experiencing generalized tonic-clonic seizures. Five percent presented with status epilepticus. Headaches, the second most common complaint, were reported in 18% of subjects. On imaging, 50% had a single lesion while 63% included pathology at the calcified stage. The lesions were parenchymal in 99.5% of cases, predominantly in the frontal lobe (59%). Thirteen percent were diagnosed incidentally on imaging, mainly in the form of isolated calcified non enhancing lesions. Albendazole was received by 55% of patients, and phenytoin was the most prescribed anti-seizure drug (57%). When long term follow up was available, 70% of the patients presenting with seizures were completely seizure free.

Conclusion

NCC is prevalent in Qatar, mainly within the large Southeast Asian immigrant population. NCC is currently a significant contributor to the epilepsy burden in Qatar, often with a good outcome regarding seizure control. NCC with intraparenchymal single lesion shares a large proportion of our cohort.

A Case of a Seven-Year-old boy with Epilepsy with Myoclonic Absence: Importance of Seizure Semiology, Genetic Etiology, and Electroencephalogram Correlation for Timely Intervention

Epilepsy with myoclonic absence (EMA) is a rare disorder with a mean age of onset of 7 years. It is characterized clinically by rhythmic, myoclonic jerking of the head, extremities or both, with impairment of consciousness and an ictal electroencephalogram (EEG) pattern of 3 Hz bilateral, synchronous and symmetrical spike and wave discharges. Prognosis is guarded and most patients are pharmaco-resistant. We present a case of EMA, found to have a FOXP1 gene pathogenic variation and a variance of unknown significance in the MBD5 gene, who was admitted to the intensive care unit in super-refractory status epilepticus. Given the overlap in symptoms of syndromes including myoclonic-astatic epilepsy, childhood absence epilepsy and juvenile myoclonic epilepsy, a detailed seizure semiology with EEG correlation, cannot be over emphasized. In this case, the genetic etiology may lend an interesting insight to the severity and prognosis.

Cardiac morbidity and mortality associated with the use of lamotrigine

OBJECTIVE

The US Food and Drug Administration recently issued a warning against the use of the antiseizure medication lamotrigine in people at risk of cardiac rhythm and conduction abnormalities. This study assessed the risk of cardiac morbidity and mortality in new users of lamotrigine.

METHODS

In a Danish population-based cohort study, we followed cohort members aged ≥15 years for the first 2 years after they initiated lamotrigine therapy. The main outcomes were cardiac conduction disorders in people without pre-existing cardiac morbidity and all-cause mortality in people with pre-existing cardiac morbidity. Cox proportional hazards models provided hazard ratios (HRs) and corresponding 95% confidence intervals (CIs) for comparison of the risk in current versus past users of lamotrigine.

RESULTS

There were 91 949 (36 618 males [39.8%]) new users of lamotrigine (median age = 45.7 years, interquartile range = 32.0-60.2 years). Among users without pre-existing cardiac disease (n = 86 769), 194 (.23%) developed a cardiac conduction disorder. Comparison of the risk in current and past lamotrigine treatment periods yielded an adjusted HR of new onset cardiac conduction disorder of 1.03 (95% CI = .76-1.40). Among users with pre-existing cardiac disease (n = 5180), 1150 (22.2%) died. Comparison of the risk in current and past lamotrigine treatment periods yielded an adjusted HR for all cause-mortality of 1.05 (95% CI = .93-1.19).

SIGNIFICANCE

In this large population-based study, lamotrigine use was associated neither with a risk of cardiac conduction disorders in people without pre-existing cardiac morbidity nor with all-cause mortality in people with pre-existing cardiac morbidity.

TRPC channels as emerging targets for seizure disorders

Epilepsy is characterized by seizures of diverse types that affect about 1-2% of the population worldwide. Current antiseizure medications are unsatisfactory, as they merely provide symptomatic relief, are ineffective in about one-third of patients, and cause unbearable adverse effects. Transient receptor potential canonical (TRPC) channels are a group of nonselective cation channels involved in many physiological functions. In this review, we provide an overview of recent preclinical studies using both genetic and pharmacological strategies that reveal these receptor-operated calcium-permeable channels may also play fundamental roles in many aspects of epileptic seizures. We also propose that TRPC channels represent appealing targets for epilepsy treatment, with a goal of helping to advance the discovery and development of new antiseizure and/or antiepileptogenic therapies.

Classification of antiseizure drugs in cultured neuronal networks using multielectrode arrays and unsupervised learning

OBJECTIVE

Antiseizure drugs (ASDs) modulate synaptic and ion channel function to prevent abnormal hypersynchronous or excitatory activity arising in neuronal networks, but the relationship between ASDs with respect to their impact on network activity is poorly defined. In this study, we first investigated whether different ASD classes exert differential impact upon network activity, and we then sought to classify ASDs according to their impact on network activity.

METHODS

We used multielectrode arrays (MEAs) to record the network activity of cultured cortical neurons after applying ASDs from two classes: sodium channel blockers (SCBs) and γ-aminobutyric acid type A receptor-positive allosteric modulators (GABA PAMs). A two-dimensional representation of changes in network features was then derived, and the ability of this low-dimensional representation to classify ASDs with different molecular targets was assessed.

RESULTS

A two-dimensional representation of network features revealed a separation between the SCB and GABA PAM drug classes, and could classify several test compounds known to act through these molecular targets. Interestingly, several ASDs with novel targets, such as cannabidiol and retigabine, had closer similarity to the SCB class with respect to their impact upon network activity.

SIGNIFICANCE

These results demonstrate that the molecular target of two common classes of ASDs is reflected through characteristic changes in network activity of cultured neurons. Furthermore, a low-dimensional representation of network features can be used to infer an ASDs molecular target. This approach may allow for drug screening to be performed based on features extracted from MEA recordings.

PROVE-Phase IV Study of Perampanel in Real-World Clinical Care of Patients with Epilepsy: Interim Analysis in Pediatric Patients

PROVE is a retrospective, phase IV study assessing retention, dosing, efficacy, and safety of perampanel when administered to patients during routine clinical care. We report an interim analysis of preadolescent (1 to <12 years) and adolescent (12 to <18 years) patients. Data were obtained from medical records of patients with epilepsy initiating perampanel after January 1, 2014; cut-off date for this analysis was October 10, 2018. Overall, 151 preadolescent and 183 adolescent patients were included. Retention rates following 24 months on perampanel were 42.5% (preadolescent subgroup; n = 31/73) and 55.7% (adolescent subgroup; n = 54/97). Treatment-emergent adverse events occurred in 53 (35.1%) preadolescent (most common: aggression, irritability, and somnolence) and 78 (42.6%) adolescent patients (most common: somnolence, aggression, and dizziness). These data indicate that daily oral doses of perampanel are generally well tolerated during routine clinical care, with favorable retention rates for ≤2 years, in patients aged 1 to <18 years.

Cognitive reawakening and improved quality of life achieved after discontinuing 16 years of anti-seizure treatment with topiramate

A 42-year-old female patient with epilepsy and a co-morbid migraine suffered from the severe cognitive side effects of topiramate (TPM) for more than 16 years with detrimental consequences for her daily functioning, career, and social interaction. Even a prodromal stage of dementia was suggested, giving rise to fears of developing a neurodegenerative disease. Recently, cognitive monitoring of attention and executive function before and after withdrawal of TPM revealed a significant recovery from the severe negative cognitive side effects of the long-standing and inefficacious antiseizure medication (ASM). Whereas the side effects were reversible after cessation, their consequences for the patient`s biography were permanent. A considerable increase in quality of life, however, was observed without TPM and family members were impressed by the improvements. This case illustrates the potentially severe consequences of negative cognitive side effects which affect daily functioning, career and social life, thus underscoring the importance of being knowledgeable of the potential cognitive risks when prescribing an ASM. Because cognitive side effects may not depend solely on ASM choice and drug load, but also on individual idiosyncratic intolerances, and patients might stay on their treatment for many years, cognitive monitoring is highly recommended.

Utility and Safety of Perampanel in Pediatric FIRES and Other Drug-Resistant Epilepsies

Perampanel is a novel antiepileptic drug, which antagonises AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid) glutamate receptor. We describe perampanel as an adjunctive treatment for FIRES (febrile infection-related epilepsy syndrome) and other drug-resistant epilepsies. A single-centre, observational, retrospective study involving 20 pediatric patients was conducted. Perampanel was started for three patients with FIRES, achieving seizure cessation in two patients within a day and on days 19 and 32 of illness. Doses used ranged from 4 to 12 mg/day, without any adverse effects reported or discontinuation of therapy. Responder-rate for other drug-resistant epilepsies is 25%. Median time to achieve ≥50% seizure reduction was 80 days (range: 26-326 days). Adverse effect reported in 47% of the patients includes central nervous system-related, and thrombocytopenia. Eight patients discontinued perampanel, because of ineffectiveness or adverse effects. The median time on perampanel before discontinuation was 179 days (range: 94-345 days). Perampanel may be of benefit in pediatrics FIRES and is of utility in other drug-resistant epilepsies.

Single-Target Versus Multi-Target Drugs Versus Combinations of Drugs With Multiple Targets: Preclinical and Clinical Evidence for the Treatment or Prevention of Epilepsy

Rationally designed multi-target drugs (also termed multimodal drugs, network therapeutics, or designed multiple ligands) have emerged as an attractive drug discovery paradigm in the last 10-20 years, as potential therapeutic solutions for diseases of complex etiology and diseases with significant drug-resistance problems. Such agents that modulate multiple targets simultaneously are developed with the aim of enhancing efficacy or improving safety relative to drugs that address only a single target or to combinations of single-target drugs. Although this strategy has been proposed for epilepsy therapy >25 years ago, to my knowledge, only one antiseizure medication (ASM), padsevonil, has been intentionally developed as a single molecular entity that could target two different mechanisms. This novel drug exhibited promising effects in numerous preclinical models of difficult-to-treat seizures. However, in a recent randomized placebo-controlled phase IIb add-on trial in treatment-resistant focal epilepsy patients, padsevonil did not separate from placebo in its primary endpoints. At about the same time, a novel ASM, cenobamate, exhibited efficacy in several randomized controlled trials in such patients that far surpassed the efficacy of any other of the newer ASMs. Yet, cenobamate was discovered purely by phenotype-based screening and its presumed dual mechanism of action was only described recently. In this review, I will survey the efficacy of single-target vs. multi-target drugs vs. combinations of drugs with multiple targets in the treatment and prevention of epilepsy. Most clinically approved ASMs already act at multiple targets, but it will be important to identify and validate new target combinations that are more effective in drug-resistant epilepsy and eventually may prevent the development or progression of epilepsy.

The ups and downs of alkyl-carbamates in epilepsy therapy: How does cenobamate differ?

Since 1955, several alkyl-carbamates have been developed for the treatment of anxiety and epilepsy, including meprobamate, flupirtine, felbamate, retigabine, carisbamate, and cenobamate. They have each enjoyed varying levels of success as antiseizure drugs; however, they have all been plagued by the emergence of serious and sometimes life-threatening adverse events. In this review, we compare and contrast their predominant molecular mechanisms of action, their antiseizure profile, and where possible, their clinical efficacy. The preclinical, clinical, and mechanistic profile of the prototypical γ-aminobutyric acidergic (GABAergic) modulator phenobarbital is included for comparison. Like phenobarbital, all of the clinically approved alkyl-carbamates share an ability to enhance inhibitory neurotransmission through modulation of the GABA_A receptor, although the specific mechanism of interaction differs among the different drugs discussed. In addition, several alkyl-carbamates have been shown to interact with voltage-gated ion channels. Flupirtine and retigabine share an ability to activate K⁺ currents mediated by KCNQ (Kv7) K⁺ channels, and felbamate, carisbamate, and cenobamate have been shown to block Na⁺ channels. In contrast to other alkyl-carbamates, cenobamate seems to be unique in its ability to preferentially attenuate the persistent rather than transient Na⁺ current. Results from recent randomized controlled clinical trials with cenobamate suggest that this newest antiseizure alkyl-carbamate possesses a degree of efficacy not witnessed since felbamate was approved in 1993. Given that ceno-bamate's mechanistic profile is unique among the alkyl-carbamates, it is not clear whether this impressive efficacy reflects an as yet undescribed mechanism of action or whether it possesses a unique synergy between its actions at the GABA_A receptor and on persistent Na⁺ currents. The high efficacy of cenobamate is, however, tempered by the risk of serious rash and low tolerability at higher doses, meaning that further safety studies and clinical experience are needed to determine the true clinical value of cenobamate.

Clinical Management of Drug Resistant Epilepsy: A Review on Current Strategies

Drug resistant epilepsy (DRE) is defined as the persistence of seizures despite at least two syndrome-adapted antiseizure drugs (ASD) used at efficacious daily dose. Despite the increasing number of available ASD, about a third of patients with epilepsy still suffer from drug resistance. Several factors are associated with the risk of evolution to DRE in patients with newly diagnosed epilepsy, including epilepsy onset in the infancy, intellectual disability, symptomatic epilepsy and abnormal neurological exam. Pharmacological management often consists in ASD polytherapy. However, because quality of life is driven by several factors in patients with DRE, including the tolerability of the treatment, ASD management should try to optimize efficacy while anticipating the risks of drug-related adverse events. All patients with DRE should be evaluated at least once in a tertiary epilepsy center, especially to discuss eligibility for non-pharmacological therapies. This is of paramount importance in patients with drug resistant focal epilepsy in whom epilepsy surgery can result in long-term seizure freedom. Vagus nerve stimulation, deep brain stimulation or cortical stimulation can also improve seizure control. Lastly, considering the effect of DRE on psychologic status and social integration, comprehensive care adaptations are always needed in order to improve patients' quality of life.

Phenobarbital and midazolam suppress neonatal seizures in a noninvasive rat model of birth asphyxia, whereas bumetanide is ineffective

OBJECTIVE

Neonatal seizures are the most frequent type of neurological emergency in newborn infants, often being a consequence of prolonged perinatal asphyxia. Phenobarbital is currently the most widely used antiseizure drug for treatment of neonatal seizures, but fails to stop them in ~50% of cases. In a neonatal hypoxia-only model based on 11-day-old (P11) rats, the NKCC1 inhibitor bumetanide was reported to potentiate the antiseizure activity of phenobarbital, whereas it was ineffective in a human trial in neonates. The aim of this study was to evaluate the effect of clinically relevant doses of bumetanide as add-on to phenobarbital on neonatal seizures in a noninvasive model of birth asphyxia in P11 rats, designed for better translation to the human term neonate.

METHODS

Intermittent asphyxia was induced for 30 minutes by exposing the rat pups to three 7 + 3-minute cycles of 9% and 5% O₂ at constant 20% CO₂ . Drug treatments were administered intraperitoneally either before or immediately after asphyxia.

RESULTS

All untreated rat pups had seizures within 10 minutes after termination of asphyxia. Phenobarbital significantly blocked seizures when applied before asphyxia at 30 mg/kg but not 15 mg/kg. Administration of phenobarbital after asphyxia was ineffective, whereas midazolam (0.3 or 1 mg/kg) exerted significant antiseizure effects when administered before or after asphyxia. In general, focal seizures were more resistant to treatment than generalized convulsive seizures. Bumetanide (0.3 mg/kg) alone or in combination with phenobarbital (15 or 30 mg/kg) exerted no significant effect on seizure occurrence.

SIGNIFICANCE

The data demonstrate that bumetanide does not increase the efficacy of phenobarbital in a model of birth asphyxia, which is consistent with the negative data of the recent human trial. The translational data obtained with the novel rat model of birth asphyxia indicate that it is a useful tool to evaluate novel treatments for neonatal seizures.

Management of Infantile Spasms During the COVID-19 Pandemic

Circumstances of the COVID-19 pandemic have mandated a change to standard management of infantile spasms. On April 6, 2020, the Child Neurology Society issued an online statement of immediate recommendations to streamline diagnosis and treatment of infantile spasms with utilization of telemedicine, outpatient studies, and selection of first-line oral therapies as initial treatment. The rationale for the recommendations and specific guidance including follow-up assessment are provided in this manuscript. These recommendations are indicated as enduring if intended to outlast the pandemic, and limited if intended only for the pandemic health care crisis but may be applicable to future disruptions of health care delivery.

Antiseizure drugs and risk of developing smoking-related chronic obstructive pulmonary disease or lung cancer: A population-based case-control study

AIMS

To determine whether enzyme-inducing antiseizure drugs (ASDs) affect the risk of developing chronic obstructive pulmonary disease (COPD) or lung cancer in smokers.

METHODS

Cases of COPD and lung cancer and matched controls without these conditions were identified from a population of smokers with ≥1 prescription for any type of ASD in the Clinical Practice Research Datalink UK database of patients managed in primary care (1995-2016). A matched case-control study was performed utilising multivariate logistic regression analyses of exposure to enzyme-inducing ASDs compared to non-enzyme-inducing ASDs. The duration of ASD exposure and level of tobacco exposure were also assessed.

RESULTS

We identified 5952 incident COPD and 1373 incident lung cancer cases, and 59 328 and 13 681 matched controls, respectively. Compared with never use, ever use of enzyme-inducing ASDs was associated with slightly decreased risk estimates of COPD (adjusted odds ratio: 0.85, 95% confidence interval: 0.81-0.89) and lung cancer (adjusted odds ratio: 0.82, 95% confidence interval: 0.73-0.92). These risk estimates were attenuated in heavy smokers.

CONCLUSION

We found slightly decreased risk estimates of COPD and lung cancer among smokers taking enzyme-inducing ASDs and hypothesise that this may be related to induction of detoxification of tobacco-specific lung toxins.

Drug-Drug Interactions Between Cannabidiol and Lithium

Epidiolex^® (Cannabidiol- CBD) is approved for epilepsy associated with Dravet syndrome (DS) and Lennox-Gastaut syndrome (LGS) in patients over 2 years of age. Common side effects include somnolence and diarrhea. Recent studies have demonstrated interactions between cannabidiol and several other antiseizure medications. However, little is known regarding interactions between cannabidiol and other classes of medications. We discuss an autistic patient with LGS and significant psychiatric comorbidities who was being treated with multiple antiseizure and psychiatric medications, including lithium, when CBD was added to his medical regimen. Several weeks after initiating CBD therapy, he developed hypersomnolence, ataxia and decreased oral intake and was found to have lithium toxicity. Lithium was discontinued and his symptoms resolved. He remains on CBD and 2 other antiseizure medications, seizure-free with improved behavior. We review mechanisms of action and pharmacokinetics of CBD and discuss possible explanations for lithium toxicity in this patient.

A perspective on the physicochemical and biopharmaceutic properties of marketed antiseizure drugs-From phenobarbital to cenobamate and beyond

The success rate from first time in man to regulatory approval of central nervous system (CNS) drugs is lower than the overall success rate across all therapeutic indications (eg, cardiovascular, infectious diseases). To understand the reasons for drug-candidate failure and to capture trends in antiseizure drug (ASD) design, we have analyzed the physicochemical and biopharmaceutical properties of marketed ASDs in comparison with new ASDs in development. Our comparative analysis included molecular weight (MW), logP, polar surface area (PSA), the "Lipinski rule of five," and the CNS Multiparameter Optimization (MPO) score. LogP is the logarithm of a drug-partition coefficient (P) between n-octanol and water. PSA is the molecule's surface sum of its polar atoms. ASDs' biopharmaceutical properties were classified according to their water solubility, permeability, and route of elimination as outlined by the Biopharmaceutics Classification System (BCS) and Biopharmaceutics Drug Disposition Classification System (BDDCS). For old ASDs (1912-1990), logP, PSA, and CNS MPO values ranged between 0.4 and 2.8, 37 and 87 Å² , and 4.4 and 6.0, respectively. For second-generation ASDs (1990-2008), PSA values ranged between 39 and 116 Å² . However, logP values showed a difference between the lipophilic (logP = 0.3-3.21) and hydrophilic (logP = -0.6 to -2.16) ASDs. For third-generation ASDs (2008-2020), logP and PSA ranged between 0.3 and 3.5 and between 57 and 76 Å² , respectively. The mean CNS MPO scores of all marketed ASDs were similar, ranging between 4.9 and 5.4, and were similar to those of the ASDs in development (3.5-5.8). Most ASDs belong to BCS and BDDCS classes 1 and 2. MW, logP, CNS MPO score, and PSA assess lipophilicity and correlate with antiseizure activity. To succeed, a new small-molecule ASD must have MW < 375 and PSA < 140Ų , belong to BCS and/or BDDCS class 1 or 2, and obey the Lipinski rule of five: logP < 5, MW < 500, and <5 and <10 of hydrogen-bond donors and acceptors, respectively. The similarity in the MW, logP, and PSA values of marketed and new drugs in development indicates a conservative trend in ASD design.

Epilepsy and EEG Phenotype of SLC13A5 Citrate Transporter Disorder

Mutations in the SLC13A5 gene, a sodium citrate cotransporter, cause a rare autosomal recessive epilepsy (EIEE25) that begins during the neonatal period and is associated with motor and cognitive impairment. Patient's seizure burden, semiology, and electroencephalography (EEG) findings have not been well characterized. Data on 23 patients, 3 months to 29 years of age are reported. Seizures began during the neonatal period in 22 patients. Although seizures are quite severe in many patients later in life, seizure freedom was attainable in a minority of patients. Multiple patients' chronic seizure management included a few common medications, phenobarbital and valproic acid in particular. Patients EEGs had a relatively well-preserved background for age, even in the face of frequent seizures, little slowing and multiple normal EEGs and do not support an epileptic encephalopathy. Other causes for the motor and cognitive delay beyond epilepsy warrant further study.

Evaluation of subchronic administration of antiseizure drugs in spontaneously seizing rats

Objective

Approximately 30% of patients with epilepsy do not experience full seizure control on their antiseizure drug (ASD) regimen. Historically, screening for novel ASDs has relied on evaluating efficacy following a single administration of a test compound in either acute electrical or chemical seizure induction. However, the use of animal models of spontaneous seizures and repeated administration of test compounds may better differentiate novel compounds. Therefore, this approach has been instituted as part of the National Institute of Neurological Disorders and Stroke Epilepsy Therapy Screening Program screening paradigm for pharmacoresistant epilepsy.

Methods

Rats were treated with intraperitoneal kainic acid to induce status epilepticus and subsequent spontaneous recurrent seizures. After 12 weeks, rats were enrolled in drug screening studies. Using a 2‐week crossover design, selected ASDs were evaluated for their ability to protect against spontaneous seizures, using a video‐electroencephalographic monitoring system and automated seizure detection. Sixteen clinically available compounds were administered at maximally tolerated doses in this model. Dose intervals (1‐3 treatments/d) were selected based on known half‐lives for each compound.

Results

Carbamazepine (90 mg/kg/d), phenobarbital (30 mg/kg/d), and ezogabine (15 mg/kg/d) significantly reduced seizure burden at the doses evaluated. In addition, a dose‐response study of topiramate (20‐600 mg/kg/d) demonstrated that this compound reduced seizure burden at both therapeutic and supratherapeutic doses. However, none of the 16 ASDs conferred complete seizure freedom during the testing period at the doses tested.

Significance

Despite reductions in seizure burden, the lack of full seizure freedom for any ASD tested suggests that this screening paradigm may be useful for testing novel compounds with potential utility in pharmacoresistant epilepsy.

Analysis of antiseizure drug-related adverse reactions from the electronic health record using the common data model

OBJECTIVE

Antiseizure drugs (ASDs) are known to cause a wide range of adverse drug reactions (ADRs). Recently, electronic health care data using the common data model (CDM) have been introduced and commonly adopted in pharmacovigilance research. We aimed to analyze ASD-related ADRs using CDM and to assess the feasibility of CDM analysis in monitoring ADR in a single tertiary hospital.

METHODS

We selected five ASDs: oxcarbazepine (OXC), lamotrigine (LTG), levetiracetam (LEV), valproic acid (VPA), and topiramate (TPM). Patients diagnosed with epilepsy and exposed to monotherapy with one of the ASDs before age 18 years were included. We measured four ADR outcomes: (1) hematologic abnormality, (2) hyponatremia, (3) elevation of liver enzymes, and (4) subclinical hypothyroidism. We performed a subgroup analysis to exclude the effects of concomitant medications.

RESULTS

From the database, 1344 patients were included for the study. Of the 1344 patients, 436 were receiving OXC, 293 were receiving LTG, 275 were receiving LEV, 180 were receiving VPA, and 160 were receiving TPM. Thrombocytopenia developed in 14.1% of patients taking VPA. Hyponatremia occurred in 10.5% of patients taking OXC. Variable ranges of liver enzyme elevation were detected in 19.3% of patients taking VPA. Subclinical hypothyroidism occurred in approximately 21.5% to 28% of patients with ASD monotherapy, which did not significantly differ according to the type of ASD. In a subgroup analysis, we observed similar ADR tendencies, but with less thrombocytopenia in the TPM group.

SIGNIFICANCE

The incidence and trends of ADRs that were evaluated by CDM were similar to the previous literature. CDM can be a useful tool for analyzing ASD-related ADRs in a multicenter study. The strengths and limitations of CDM should be carefully addressed.

Safety and Tolerability of Adjunctive Eslicarbazepine Acetate in Pediatric Patients (Aged 4-17 Years) With Focal Seizures

OBJECTIVE

To evaluate the safety and tolerability of adjunctive eslicarbazepine acetate (ESL) in pediatric patients (aged 4-17 years) with refractory focal seizures.

METHODS

Pooled safety data from patients aged 4-17 years in Study 208 (NCT01527513) and Study 305 (NCT00988156) were analyzed. Both were randomized, double-blind, placebo-controlled studies of ESL as adjunctive treatment in pediatric patients with refractory focal seizures receiving 1 or 2 antiepileptic drugs. Incidences of treatment-emergent adverse events (TEAEs), serious adverse events (SAEs), TEAEs leading to discontinuation, and TEAEs of special interest were evaluated.

RESULTS

The safety population comprised 362 patients (placebo, n = 160; ESL, n = 202). The overall incidence of TEAEs was similar between the ESL (67.8%) and placebo groups (65.6%), with no clear dose-response relationship. The most frequently reported TEAEs with ESL were headache, somnolence, vomiting, and diplopia. Overall incidences of SAEs and TEAEs leading to discontinuation were higher with ESL versus placebo (9.9% vs 5.0% and 5.9% vs 2.5%, respectively). The majority of SAEs with ESL occurred in Study 305. Two deaths were reported, 1 with ESL (0.5%) due to cluster seizures (resulting in herniation of the cerebellar tonsils) and 1 with placebo (0.6%) due to asphyxia. TEAEs related to allergic reaction, hyponatremia, hypothyroidism, cytopenia, seizure exacerbation, cognitive dysfunction, psychiatric disorders, or suicide occurred infrequently (<9%).

CONCLUSION

Adjunctive ESL was generally well tolerated in children aged 4-17 years with focal seizures. The safety profile of ESL in children was comparable to that observed in adults.

Interleukin-6 Blockade With Tocilizumab in Anakinra-Refractory Febrile Infection-Related Epilepsy Syndrome (FIRES)

Febrile infection-related epilepsy syndrome (FIRES) is characterized by new onset refractory status epilepticus in a previously healthy child that is associated with poor cognitive outcomes and chronic epilepsy. Innate immune system dysfunction is hypothesized to be a key etiologic contributor, with a potential role for immunotherapy blocking pro-inflammatory cytokines, such as interleukin-1β and interleukin-6. We present a case of FIRES refractory to anakinra, an interleukin-1 receptor antagonist, subsequently treated with the ketogenic diet and tocilizumab, an interleukin-6 receptor antagonist, temporally associated with seizure cessation and a favorable 1-year outcome.

Novel study design to assess the efficacy and tolerability of antiseizure medications for focal-onset seizures in infants and young children: A consensus document from the regulatory task force and the pediatric commission of the International League against Epilepsy (ILAE), in collaboration with the Pediatric Epilepsy Research Consortium (PERC)

High-quality placebo-controlled drug trials for focal-onset seizures in infants and children younger than 4 years have become increasingly difficult to perform because of eligibility constraints and onerous study designs. Traditional designs used in these populations require a high baseline seizure frequency, two hospitalizations for video-electroencephalography (video-EEG) monitoring, and willingness to accept potential exposure to placebo when the drugs to be tested are usually already available for off-label prescription. To address these constraints, the International League Against Epilepsy (ILAE) regulatory taskforce and the ILAE pediatric commission, in collaboration with the Pediatric Epilepsy Research Consortium (PERC), propose a novel trial design which involves seizure counting by caregivers based on previous video-EEG/video validation of specific seizure semiologies. We present a novel randomized placebo-controlled trial design intended to be used for studying new antiseizure medications (ASMs) for focal-onset seizures (FOS) in children aged one month to four years. This design uses "time to Nth seizure" as the primary outcome and incorporates a new element of variable baseline duration. This approach permits enrollment of infants with lower seizure burden, who might not have video-EEG-recorded seizures within 2-3 days of monitoring. Repeated hospitalizations for video-EEG recordings are avoided, and duration of baseline and exposure to placebo or ineffective treatment(s) are minimized. By broadening eligibility criteria, reducing risks from prolonged placebo exposure, and relying on validated recording of seizure counting by caregivers, clinical trials will be likely to be completed more efficiently than in the recent past.

Two Patients With KCNT1-Related Epilepsy Responding to Phenobarbital and Potassium Bromide

KCNT1 encodes a sodium-activated potassium channel highly expressed in the brain, regulating hyperpolarization following repetitive firing. Mutations in KCNT1 were originally implicated in autosomal-dominant nocturnal frontal lobe epilepsy and epilepsy of infancy with migrating focal seizures. It is now known that there is variability in phenotypic expression and incomplete penetrance. We describe 2 patients with KCNT1-related epilepsy, one with epilepsy of infancy with migrating focal seizures and one with multifocal epilepsy. As most patients with KCNT1 variants have treatment-resistant epilepsy, drugs that specifically target the KCNT1 channel have been of great interest. Quinidine, a broad-spectrum potassium channel blocker, has shown promise; however, clinical trial results have been variable. Our patient with epilepsy of infancy with migrating focal seizures did not respond to a trial of quinidine at 6 weeks of age-one of the earliest reported quinidine trials in the literature for KCNT1-related epilepsy. This indicates that timing of treatment and response may not be related. Both patients responded to high-dose phenobarbital. The patient with epilepsy of infancy with migrating focal seizures also had a significant reduction in seizures with potassium bromide (KBr). Our data suggest that alternative therapies to quinidine should be considered as a therapeutic option for patients with KCNT1-related epilepsy. Although improved seizure control led to parent-reported improvements in neurodevelopment, it is unknown if phenobarbital and KBr impact the overall developmental trajectory of patients with KCNT1-related epilepsy. Further multicenter longitudinal studies are required.

Evaluation of antiseizure drug efficacy and tolerability in the rat lamotrigine-resistant amygdala kindling model

OBJECTIVE

The lamotrigine-resistant amygdala kindling model uses repeated administration of a low dose of lamotrigine during the kindling process to produce resistance to lamotrigine, which also extends to some other antiseizure drugs (ASDs). This model of pharmacoresistant epilepsy has been incorporated into the testing scheme utilized by the Epilepsy Therapy Screening Program (ETSP). Although some ASDs have been evaluated in this model, a comprehensive evaluation of ASD prototypes has not been reported.

METHODS

Following depth electrode implantation and recovery, rats were exposed to lamotrigine (5 mg/kg, i.p.) prior to each stimulation during the kindling development process (~3 weeks). A test dose of lamotrigine was used to confirm that fully kindled rats were lamotrigine-resistant. Efficacy (unambiguous protection against electrically elicited convulsive seizures) was defined as a Racine score < 3 in the absence of overt compound-induced side effects. Various ASDs, comprising several mechanistic classes, were administered to fully kindled, lamotrigine-resistant rats. Where possible, multiple doses of each drug were administered in order to obtain median effective dose (ED50) values.

RESULTS

Five sodium channel blockers tested (eslicarbazepine, lacosamide, lamotrigine, phenytoin, and rufinamide) were either not efficacious or effective only at doses that were not well-tolerated in this model. In contrast, compounds targeting either GABA receptors (clobazam, clonazepam, phenobarbital) or GABA-uptake proteins (tiagabine) produced dose-dependent efficacy against convulsive seizures. Compounds acting to modulate Ca2+ channels show differential activity: Ethosuximide was not effective, whereas gabapentin was moderately efficacious. Ezogabine and valproate were also highly effective, whereas topiramate and levetiracetam were not effective at the doses tested.

SIGNIFICANCE

These results strengthen the conclusion that the lamotrigine-resistant amygdala kindling model demonstrates pharmacoresistance to certain ASDs, including, but not limited to, sodium channel blockers, and supports the utility of the model for helping to identify compounds with potential efficacy against pharmacoresistant seizures.

"Chance Takers Are Accident Makers": Are Patients With Epilepsy Really Taking a Chance When They Drive?

This review compiles scientific data about the real dangers faced by people with epilepsy (PWE) who drive. Those include risks of motor vehicle accidents (MVA) in PWE as compared with controls (individuals without epilepsy) and as compared with persons with other medical conditions that impact fitness to drive. Data regarding Accident rates as related to seizure free intervals (SFI), single vs. multiple seizure events, and/or antiseizure drug (ASD) taper and reintroduction are discussed. Variation in state, national, and international laws and guidance for non-commercial and commercial drivers is highlighted, along with some related reasons for driving restrictions. The review concludes by emphasizing the importance of physicians educating patients about local driving laws and about risks of ASD non-adherence. The need for a broader, multi-stakeholder re-examination of driving regulations for PWE is noted.

Moving beyond sodium valproate: choosing the right anti-epileptic drug in children

Introduction: Sodium valproate is a widely used anti-epileptic drug with a broad spectrum of activity and mechanism of action. It has consequently been the first-line drug for most seizure types in children for the past fifty years. A wide range of side effects come along with these exceptional properties, including teratogenicity and neuro-cognitive impairments in offspring. Therefore, epilepsy treatment in children and adolescents should be reassessed in light of newer antiepileptic drugs as well as a more targeted-approach with older drugs. Areas covered: The authors review the main concerns of valproate use in terms of adverse effects on different systems and drug interactions. The current alternatives to valproate in absence, myoclonic, tonic-clonic and focal onset seizures in children/adolescents are also reviewed. Expert opinion: There are several issues that research should address in antiepileptic therapy and in clinical studies with children, given the peculiarity of this population. Future perspectives in epilepsy therapy should now lead towards an individualized treatment.

Pediatric Epilepsy Mechanisms: Expanding the Paradigm of Excitation/Inhibition Imbalance

Mechanisms underlying seizures and epilepsy have traditionally been considered to involve abnormalities of ion channels or synaptic function. Those considerations gave rise to the excitation/inhibition (E/I) imbalance theory, whereby increased excitation, decreased inhibition, or both favor a hyperexcitable state and an increased propensity for seizure generation and epileptogenesis. Several recent findings warrant reconsideration and expansion of the E/I hypothesis: novel genetic mutations have been identified that do not overtly affect E/I balance; neurotransmitters may exert paradoxical effects, especially during development; anti-seizure medications do not necessarily work by decreasing excitation or increasing inhibition; and metabolic factors participate in the regulation of neuronal and network excitability. These novel conceptual and experimental advances mandate expansion of the E/I paradigm, with the expectation that new and exciting therapies will emerge from this broadened understanding of how seizures and epilepsy arise and progress.

Cost-Effectiveness of Evaluation of Children With Epilepsy in the Emergency Department: Need for Investment in Patient Education

We aimed to study cost-effectiveness of seizure evaluation of children with epilepsy in the emergency department (ED). We reviewed epilepsy patients seen at our ED for 1 year. Age, laboratory and neuroimaging results, treatment, disposition, and usefulness of the visit (need for hospitalization, clinical improvement) were analyzed. We identified 330 patients, aged 23 days-21 years, 190 (57.5%) had blood tests, 45 (13.6%) urinalysis, 2 (0.6%) cerebrospinal fluid testing, and 44 neuroimaging studies (13.3%). Tests' positive yield were 41%, 11%, 0%, and 4.5%, respectively. One-third of patients (n = 122) were treated with antiepileptic drugs. Other treatments were administered to 44 (13.3%). One hundred eighteen patients (35.7%) were admitted to our hospital, 208 (63%) discharged to home. Two hundred eight visits were useful (63%). One-third of visits did not provide useful patient care. Their visits were expensive and not very cost-effective. Investment in patient education could decrease unnecessary ED visits.

What goes up must come down: homeostatic synaptic plasticity strategies in neurological disease

Brain activity levels are tightly regulated to minimize imbalances in activity state. Deviations from the normal range of activity are deleterious and often associated with neurological disorders. To maintain optimal levels of activity, regulatory mechanisms termed homeostatic synaptic plasticity establish desired 'set points' for neural activity, monitor the network for deviations from the set point and initiate compensatory responses to return activity to the appropriate level that permits physiological function [1,2]. We speculate that impaired homeostatic control may contribute to the etiology of various neurological disorders including epilepsy and Alzheimer's disease, two disorders that exhibit hyperexcitability as a key feature during pathogenesis. Here, we will focus on recent progress in developing homeostatic regulation of neural activity as a therapeutic tool.

Clinical Experience With Perampanel for Refractory Pediatric Epilepsy in One Canadian Center

Perampanel (PER) is a new antiseizure medication that inhibits the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) class of glutamate receptors. It is important for physicians to be aware of the efficacy and tolerability of new drugs in the postmarketing phase. We performed a retrospective review of our experience with perampanel at BC Children's Hospital. Twenty-four pediatric patients prescribed perampanel from 2014 to 2016 were identified. Fifteen (63%) discontinued perampanel, and 10 (42%) had greater than 50% reduction in seizures. Twelve (50%) had behavioral and 8 (33%) had nonbehavioral adverse events. One-third experienced serious adverse events. One patient experienced oculogyric crisis, which is not previously reported with perampanel. Adverse events were not dose related and were reversible. Possible risk factors for behavioral adverse events include a history of behavioral problems with other antiseizure medications and preexisting behavioral comorbidities. It is important to counsel patients about the potential for serious adverse events, particularly behavioral, when prescribing perampanel.

Case Report

Glutaminyl-tRNA synthetase (QARS) deficiency has been described to be a cause of a neurodegenerative disorder associated with severe developmental delay, microcephaly, delayed myelination, and intractable epilepsy. The epilepsy is thought to be more severe than other tRNA synthetase disorders. Only a few cases have been reported in the literature and there is little information about response to different treatment options. The ketogenic diet is a high-fat, low-carbohydrate diet that is used in treatment resistant epilepsy of various etiologies. There are reports that the diet can also improve neuro-cognitive parameters. The authors report a case of a patient with glutaminyl-tRNA synthetase deficiency and treatment resistant seizures where there was a marked and early favorable response in terms of seizures, alertness and behavior to the ketogenic diet.

Phenytoin-induced cerebellar atrophy in an epileptic boy

Epilepsy is an important health problem due to its high prevalence and potential for causing long-term morbidity. It is commonly treated in children with phenytoin sodium. It has wide pharmacokinetic variability and a narrow therapeutic range that leads to toxicity. Here, we report a case of phenytoin-induced cerebellar atrophy in a 16-year-old epileptic boy who presented to the hospital with a viral infection.