Treatment of idiopathic generalized epilepsy – a review of the evidence

Antiseizure medications for idiopathic generalized epilepsies: a systematic review and network meta-analysis

OBJECTIVES

To compare the efficacy and safety of antiseizure medications (ASMs), both as monotherapies and adjunctive therapies, for idiopathic generalized epilepsies (IGEs) and related entities.

METHODS

Two reviewers independently searched PubMed, Embase, and the Cochrane Library for relevant randomized controlled trials from December 2022 to February 2023. Studies on the efficacy and safety of ASM monotherapies or adjunctive therapies for IGEs and related entities-including juvenile myoclonic epilepsy, childhood absence epilepsy (CAE), juvenile absence epilepsy, or generalized tonic-clonic seizures alone (GTCA)-were included. Efficacy outcomes were the proportions of patients remaining seizure free for 1, 3, 6, and 12 months; safety outcomes were the proportions of any treatment-emergent adverse event (TEAE) and TEAEs leading to discontinuation. Network meta-analyses were performed in a random-effects model to obtain odds ratios and 95% confidence intervals. Rankings of ASMs were based on the surface under the cumulative ranking curve (SUCRA). This study is registered with PROSPERO (No. CRD42022372358).

RESULTS

Twenty-eight randomized controlled trials containing 4282 patients were included. As monotherapies, all ASMs were more effective than placebo, and valproate and ethosuximide were significantly better than lamotrigine. According to the SUCRA for efficacy, ethosuximide ranked first for CAE, whereas valproate ranked first for other types of IGEs. As adjunctive therapies, topiramate ranked best for GTCA as well as overall for IGEs, while levetiracetam ranked best for myoclonic seizures. For safety, perampanel ranked best (measured by any TEAE).

CONCLUSIONS

All of the studied ASMs were more effective than placebo. Valproate monotherapy ranked best overall for IGEs, whereas ethosuximide ranked best for CAE. Adjunctive topiramate and levetiracetam were most effective for GTCA and myoclonic seizures, respectively. Furthermore, perampanel had the best tolerability.

Thalamocortical circuits in generalized epilepsy: Pathophysiologic mechanisms and therapeutic targets

Generalized epilepsy affects 24 million people globally; at least 25% of cases remain medically refractory. The thalamus, with widespread connections throughout the brain, plays a critical role in generalized epilepsy. The intrinsic properties of thalamic neurons and the synaptic connections between populations of neurons in the nucleus reticularis thalami and thalamocortical relay nuclei help generate different firing patterns that influence brain states. In particular, transitions from tonic firing to highly synchronized burst firing mode in thalamic neurons can cause seizures that rapidly generalize and cause altered awareness and unconsciousness. Here, we review the most recent advances in our understanding of how thalamic activity is regulated and discuss the gaps in our understanding of the mechanisms of generalized epilepsy syndromes. Elucidating the role of the thalamus in generalized epilepsy syndromes may lead to new opportunities to better treat pharmaco-resistant generalized epilepsy by thalamic modulation and dietary therapy.

Eslicarbazepine Acetate as Adjunctive Therapy for Primary Generalized Tonic-Clonic Seizures in Adults: A Prospective Observational Study

BACKGROUND

Eslicarbazepine acetate (ESL), a novel sodium channel blocker, is approved for mono and adjunctive treatment of partial epileptic seizures with or without secondary generalization. Its efficacy in primary generalized seizures has not yet been evaluated.

OBJECTIVE

To evaluate the efficacy and safety of ESL in primary generalized tonic-clonic seizures (PGTCS) in an observational study.

METHODS

The data were collected from a prospective population-based register. Effectiveness was measured as relative reduction in standardized seizure frequency (SSF), responder rate (≥ 50% reduction in SSF), and seizure freedom rate at 6 and 12 months after initiation of ESL. Safety and tolerability were evaluated using patients' diaries.

RESULTS

Fifty-six adult patients with PGTCS were treated with ESL as adjunctive therapy. Of these, 30.4% (n = 17) had myoclonic seizures in addition to PGTCS. The retention rate after 12 months was 80.4% (n = 45). After initiating ESL therapy, reduction in SSF for PGTCS on ESL was 56.0% after 6 months and 56.9% after 12 months (p < 0.01), whereas myoclonic seizures did not show any significant improvement in frequency. The responder rate for PGTCS was 64.3% after 6 months and 66.1% after 12 months, and seizure freedom was achieved in 32.1% and 35.7%, respectively. Forty-three patients (73.2%) reported no side effects. Among the reported side effects of ESL therapy, headache (7.1%), dizziness (8.9%), tiredness (7.1%), nausea (5.4%), and hyponatremia (5.4%) were the most prevalent.

CONCLUSIONS

Our data suggest that ESL may provide additional benefits in the treatment of patients with PGTCS and motivate randomized controlled trials in this indication.

Social outcome and psychiatric comorbidity of generalized epilepsies - A case-control study

OBJECTIVE

To investigate social outcome and psychiatric comorbidity of patients with idiopathic/genetic generalized epilepsies (IGEs) and its subtypes (epilepsy with generalized tonic-clonic seizures alone [EGTCS], juvenile absence epilepsy [JAE], and juvenile myoclonic epilepsy [JME]).

METHODS

A cohort of 402 adult patients with IGE from the Danish island Funen was matched with 4020 randomly selected geography-, age-, and sex-matched controls via the Danish Civil Registration System. Based on register data, we compared social status measured by cohabitant status, educational attainment, income, affiliation to labor market, and psychiatric comorbidity.

RESULTS

As compared to controls, patients with IGE had similar cohabitant status but fewer children (no children: 59.0% vs 50.9%), and lower educational level (primary school only: 46.0% vs 37.3%), employment rate (outside of workforce: 56.7% vs 46.5%), and income (low income: 32.6% vs 24.9%) (P < 0.001 for all comparisons). Having IGE was associated with higher a proportion of psychiatric comorbidity (IGE, 22.6%; controls, 13.0%) (P < 0.001). Seizure-free patients did not differ from controls; patients with persistent seizures had lower incomes and employment rates. In the IGE subgroup analyses, JME was associated with worse social status in all parameters studied (eg, 65.9% of JME patients were outside the workforce vs 44.5% of matched controls; P < 0.001), whereas no adverse social status was identified in patients with EGTCS and JAE.

SIGNIFICANCE

Patients with IGE in general and JME in particular have poorer social status and more psychiatric comorbidity than matched population controls without epilepsy. Poor seizure control was associated with social status and may contribute to negative socioeconomic consequences associated with IGE.

Experience with Low-Dose Sodium Valproate in Idiopathic Generalized Epilepsy Patients: A Long-Term Follow-Up Study on Selective Cohort from North India

Background  Idiopathic generalized epilepsy (IGE) is found in 20 to 30% of all patients presenting with seizures. Most of the patients require lifelong drug treatment. Efficacy and tolerability are important issues while selecting the most appropriate drug for a person with IGE. Objective  The aim of this study was to look for usefulness of small dose valproate (<1,000 mg/day) in long-term treatment of IGE patients. Methods  Diagnosis of IGE made with standard criteria among all patients presenting with seizures. Patients put on full doses of valproate (>1,000 mg/day) in first year, then reduction started in next year in patients with full seizure remission, and finally maintained on lowest possible dose of valproate. Lowest dose was defined as the minimum dose without seizures (between 200 and 900 mg/day). Patients, who were refractory on monotherapy, were put on add-on drug and followed for remission and reduction in doses of valproate at minimum possible dose. Results  IGE was diagnosed in 21% of all patients presenting with seizures. Among 420 patients of IGE 368 (87.5%) were started on high-dose valproate monotherapy, 155 (42.1%) were responsive to single drug while 213 (57.9%) had been given add-on drug either lamotrigine or clonazepam or both. After minimum 3-year follow-up, 298 (81%) could be managed on low-dose valproate (<1,000 mg) without any relapse during 12 to 80 months follow-up. Conclusion  Significant number of patients with IGE can be managed on low-dose valproate with good seizure control and less side effects.

Trait impulsivity correlates with active myoclonic seizures in genetic generalized epilepsy

BACKGROUND

Juvenile myoclonic epilepsy (JME) is a common subtype of genetic generalized epilepsy (GGE) arising in adolescence and is often associated with executive function (EF) deficits. Some EF components like response inhibition have been extensively evaluated in JME, but few studies have focused upon trait impulsivity or compared between GGE subtypes. The aim of the present study was to compare the association of trait impulsivity in JME with other GGE subtypes.

METHODS

Patients with GGE aged between 14 and 40 years (n = 137) were divided into those with JME (n = 92) and those with other GGEs (n = 45: 8 childhood absence epilepsy (CAE), 22 juvenile absence epilepsy (JAE), and 15 epilepsy with generalized tonic-clonic seizures only (EGTCS)). The study participants were recruited through medical records of the general population of Buskerud County and the neighboring municipalities, covering 477,000 people or 9.1% of Norway's total population. All participants underwent a clinical interview including the Barratt Impulsiveness Scale (BIS), an established measure of trait impulsivity. We controlled for other potential predictors of BIS score using analysis of covariance (ANCOVA).

RESULTS

There were no differences between JME and other types of GGE for BIS scores, but the presence of myoclonic seizures within the last year, irrespective of GGE subtype, was independently associated with significantly increased behavioral impulsivity.

CONCLUSIONS

This study demonstrates that trait impulsivity in GGE is most strongly related to the recent occurrence of myoclonic seizures rather than GGE subtype.

Patterns and prognostic markers for treatment response in generalized epilepsies

Objective

To determine the pattern of treatment response in patients with idiopathic generalized epilepsy (IGE) and whether routinely assessed clinical and neurophysiological parameters allow predicting response to lamotrigine, levetiracetam, or valproic acid.

Methods

In 328 adult patients with IGE, demographic data, imaging, EEG data, current and prior antiepileptic treatment, treatment outcome, and side effects were analyzed from the patients' medical files and patient interviews.

Results

Seizure freedom with acceptable side effects at the first attempt was achieved in 61 (18.6%) patients. One hundred four (31.7%) patients tried ≥3 antiepileptic drugs before achieving seizure control at the last follow-up. Lamotrigine, levetiracetam, and valproic acid showed differential response rates (39.8% vs 47.5% vs 71.1%) that were most pronounced in patients with juvenile myoclonic epilepsy. The risk of having side effects was higher with valproic acid (23.7%) than with lamotrigine (10.4%) or levetiracetam (20.4%) treatment, contributing to the low retention rate of valproic acid (53.7%). Treatment resistance was associated with established risk factors. Multivariate analyses aiming at identifying clinical indicators for response to specific drugs did not reveal putative biomarkers when corrected for drug resistance.

Conclusion

Despite a high rate of seizure control, the chance of achieving seizure control and acceptable side effects at first attempt was low due to an inverse association of effectiveness and side effects of the 3 most commonly used drugs. Routinely assessed clinical parameters were not indicative for response to specific drugs.

Classification of evidence

This study provides Class II evidence that for patients with IGE, various clinical factors do not predict a response to specific antiepileptic drugs.

Curcumin and neurological diseases

Objectives: The beneficial effects of many substances have been discovered because of regular dietary consumption. This is also the case with curcumin, whose effects have been known for more than 4,000 years in Eastern countries such as China and India. A curcumin-rich diet has been known to counteract many human diseases, including cancer and diabetes, and has been shown to reduce inflammation. The effect of a curcumin treatment for neurological diseases, such as spinal muscular atrophy; Alzheimer's disease; Parkinson's disease; amyotrophic lateral sclerosis; multiple sclerosis; and others, has only recently been brought to the attention of researchers and the wider population.Methods: In this paper, we summarise the studies on this natural product, from its isolation two centuries ago to its characterisation a century later.Results: We describe its role in the treatment of neurological diseases, including its cellular and common molecular mechanisms, and we report on the clinical trials of curcumin with healthy people and patients.Discussion: Commenting on the different approaches adopted by the efforts made to increase its bioavailability.

Antiepileptic Drugs and Liver Disease

Acute, symptomatic seizures or epilepsy may complicate the course of hepatic disease. Choosing the most appropriate antiepileptic drug in this setting represents a difficult challenge, as most medications are metabolized by the liver. This article focuses on the acute and chronic treatment of seizures in patients with advanced liver disease and reviews the hepatotoxic potential of specific antiepileptic drugs. Newer antiepileptic drugs without, or with minimal, hepatic metabolism, such as levetiracetam, lacosamide, topiramate, gabapentin, and pregabalin should be used as first-line therapy. Medications undergoing extensive hepatic metabolism, such as valproic acid, phenytoin, and felbamate should be used as drugs of last resort. In special circumstances, as in patients affected by acute intermittent porphyria, exposure to most antiepileptic drugs could precipitate attacks. In this clinical scenario, bromides, levetiracetam, gabapentin, and vigabatrin constitute safe choices. For the treatment of status epilepticus, levetiracetam and lacosamide, available in intravenous preparations, are good second-line therapies after benzodiazepines fail to control seizures. Hepatotoxicity is also a rare and unexpected side effect of some antiepileptic drugs. Drugs such as valproic acid, phenytoin, and felbamate, have a well-recognized association with liver toxicity. Other antiepileptic drugs, including phenobarbital, benzodiazepines, ethosuximide, and the newer generations of antiepileptic drugs, have only rarely been linked to hepatotoxicity. Thus physicians should be mindful of the pharmacokinetic profile and the hepatotoxic potential of the different antiepileptic drugs available to treat patients affected by liver disease.

Lacosamide for uncontrolled primary generalized tonic-clonic seizures: An open-label pilot study with 59-week extension

OBJECTIVE

Assess the safety of adjunctive lacosamide for the treatment of uncontrolled primary generalized tonic-clonic seizures in patients (16-65 years) with primary generalized (genetic) epilepsy (PGE).

METHODS

An open-label pilot safety study (SP0961; NCT01118949), comprising 12 weeks' historical baseline, 4 weeks' prospective baseline, 3 weeks' titration (target: 400mg/day adjunctive lacosamide) and 6 weeks' maintenance. Patients who continued to the extension study (SP0962; NCT01118962) then received ≤59 weeks of flexible treatment (100-800mg/day lacosamide with flexible dosing of concomitant antiepileptic drugs). The primary outcomes for SP0961 were the mean change (±standard deviation) in absence seizure or myoclonic seizure days per 28days from prospective baseline to maintenance; for SP0962, the incidence of treatment-emergent adverse events (TEAEs) and withdrawals because of TEAEs.

RESULTS

Of the 49 patients who enrolled, 40 (82%) completed the pilot study and 9 discontinued (5 because of adverse events). Of the 39 patients who continued to the extension study, 10 discontinued (2 owing to TEAEs) and 29 (74%) completed the study. During the pilot study, patients reported a reduction in mean (±standard deviation) absence and myoclonic seizure days per 28days (-0.37±4.80, -2.19±5.80). Reductions were also observed during the extension study (-2.38±5.54, -2.78±6.43). Five patients in SP0961 and 2 patients in SP0962 experienced TEAEs of new or increased frequency of absence seizures or myoclonic seizures. The most common TEAEs during SP0961 were dizziness (39%) and nausea (27%), and during SP0962 were dizziness (26%) and upper respiratory tract infection (26%).

CONCLUSIONS

The safety profile of adjunctive lacosamide was similar to that previously published. Adjunctive lacosamide did not systematically worsen absence or myoclonic seizures, and appears to be well tolerated in patients with PGE.

Beyond neural cubism: promoting a multidimensional view of brain disorders by enhancing the integration of neurology and psychiatry in education

Cubism was an influential early-20th-century art movement characterized by angular, disjointed imagery. The two-dimensional appearance of Cubist figures and objects is created through juxtaposition of angles. The authors posit that the constrained perspectives found in Cubism may also be found in the clinical classification of brain disorders. Neurological disorders are often separated from psychiatric disorders as if they stemmed from different organ systems. Maintaining two isolated clinical disciplines fractionalizes the brain in the same way that Pablo Picasso fractionalized figures and objects in his Cubist art. This Neural Cubism perpetuates a clinical divide that does not reflect the scope and depth of neuroscience. All brain disorders are complex and multidimensional, with aberrant circuitry and resultant psychopharmacology manifesting as altered behavior, affect, mood, or cognition. Trainees should receive a multidimensional education based on modern neuroscience, not a partial education based on clinical precedent. The authors briefly outline the rationale for increasing the integration of neurology and psychiatry and discuss a nested model with which clinical neuroscientists (neurologists and psychiatrists) can approach and treat brain disorders.

Paradoxical exacerbation of myoclonic-astatic seizures by levetiracetam in myoclonic astatic epilepsy

Background

Levetiracetam is a broad spectrum antiepileptic drug (AED) with proven efficacy when used as adjunctive therapy against myoclonic seizures. We report two patients suffering from epilepsy with myoclonic-astatic epilepsy (MAE) who experienced a paradoxical worsening of seizures after initiation of treatment with LEV, a finding not previously described.

Case presentation

Patients included were enrolled in an ongoing large prospective study evaluating children and adults with new onset epilepsy in Lebanon conducted at the American University of Beirut Medical Center in association with the Lebanese Chapter of the International League against Epilepsy. Based on an extensive evaluation, these patients were stratified into idiopathic partial, idiopathic generalized, symptomatic partial or symptomatic generalized epilepsies. Whenever possible the electroclinical syndrome was identified according to the ILAE classification of epilepsy syndromes. Patients were subsequently followed up on regular intervals and were assessed for adverse events, and seizure recurrence.

MAE was diagnosed in five (1.6%) out of 307 consecutive children enrolled in this study. LEV was used as adjunctive therapy in four of those children with two experiencing a substantial and dose related worsening in the frequency of their myoclonic and atonic seizures.

Conclusion

LEV should be used with caution in children with MAE and an exacerbation of seizure frequency temporally related to the introduction of LEV should alert the clinician to the possibility of a paradoxical seizure exacerbation.

Antiepileptic drug therapy and monitoring

Over the past 2 decades, the number of antiepileptic drugs (AEDs) available to veterinarians has grown exponentially. Coupled with this increase is the ability to rapidly and accurately diagnose underlying brain disease with readily accessible magnetic resonance imaging. As a result, the veterinary community is attuned to the need for early treatment intervention. As more treatment choices become available, the unrelenting questions still arise are when should treatment begin, which initial drug therapy is best for our patients, when should treatment changes be considered, and finally, what are the advantages that newer drugs provide for our patients. The purpose of this chapter is to review decision-making strategies for AED therapy, provide an overview of the applicability of current AED available, and present information on the therapeutic advances in epilepsy.

Stem cell transplantation in neurological diseases: improving effectiveness in animal models

Neurological diseases afflict a growing proportion of the human population. There are two reasons for this: first, the average age of the population (especially in the industrialized world) is increasing, and second, the diagnostic tools to detect these pathologies are now more sophisticated and can be used on a higher percentage of the population. In many cases, neurological disease has a pharmacological treatment which, as in the case of Alzheimer's disease, Parkinson's disease, Epilepsy, and Multiple Sclerosis can reduce the symptoms and slow down the course of the disease but cannot reverse its effects or heal the patient. In the last two decades the transplantation approach, by means of stem cells of different origin, has been suggested for the treatment of neurological diseases. The choice of slightly different animal models and the differences in methods of stem cell preparation make it difficult to compare the results of transplantation experiments. Moreover, the translation of these results into clinical trials with human subjects is difficult and has so far met with little success. This review seeks to discuss the reasons for these difficulties by considering the differences between human and animal cells (including isolation, handling and transplantation) and between the human disease model and the animal disease model.

Transplantation of GABAergic Interneurons into the Neonatal Primary Visual Cortex Reduces Absence Seizures in Stargazer Mice

Epilepsies are debilitating neurological disorders characterized by repeated episodes of pathological seizure activity. Absence epilepsy (AE) is a poorly understood type of seizure with an estimated 30% of affected patients failing to respond to antiepileptic drugs. Thus, novel therapies are needed for the treatment of AE. A promising cell-based therapeutic strategy is centered on transplantation of embryonic neural stem cells from the medial ganglionic eminence (MGE), which give rise to gamma-aminobutyric acidergic (GABAergic) interneurons during embyronic development. Here, we used the Stargazer (Stg) mouse model of AE to map affected loci using c-Fos immunohistochemistry, which revealed intense seizure-induce activity in visual and somatosensory cortices. We report that transplantation of MGE cells into the primary visual cortex (V1) of Stg mice significantly reduces AE episodes and lowers mortality. Electrophysiological analysis in acute cortical slices of visual cortex demonstrated that Stg V1 neurons exhibit more pronounced increases in activity in response to a potassium-mediated excitability challenge than wildtypes (WT). The defective network activity in V1 was significantly altered following WT MGE transplantation, associating it with behavioral rescue of seizures in Stgs. Taken together, these findings present MGE grafting in the V1 as a possible clinical approach in the treatment of AE.

Perspective on the use of perampanel and intravenous carbamazepine for generalized seizures

INTRODUCTION

Several antiepileptic drugs are available for the treatment of epileptic patients. However, the treatment of some seizure types and novel drug formulations deserve further advances in epilepsy research.

AREAS COVERED

The authors analyze the published evidence on the efficacy of perampanel against secondarily generalized seizures (SGS) and report the currently available development of intravenous (IV) formulations of carbamazepine (CBZ), commenting on their potential in the clinical setting.

EXPERT OPINION

Perampanel is the first noncompetitive AMPA receptor antagonist to be approved as adjunctive treatment in patients with partial-onset (focal) seizures (POS) with or without secondary generalization. Apart from its efficacy and safety on POS, a consistent body of evidence supports its efficacy in SGS at a minimum dose of 8 mg/day; however, such dose appears close to the best-tolerated dose. CBZ is a poorly water-soluble compound; many efforts to develop a parenteral formulation have not been successful so far. Novel IV CBZ formulations seem to exhibit favorable pharmacokinetics along with good tolerability in animal models and in patients taking oral CBZ. Further studies are needed to assess whether larger doses will be as well tolerated, allowing IV CBZ to be used as bridge therapy when the oral route is not feasible or in patients naïve to CBZ.