Options for pharmacoresistant epilepsy in children: when medications don't work

Efficacy and Safety of Vagus Nerve Stimulation in Lennox-Gastaut Syndrome: A Scoping Review

Lennox-Gastaut syndrome (LGS) is a severe developmental and epileptic encephalopathy characterized by drug-resistant seizures, cognitive impairments, and abnormal electroencephalographic patterns. Vagus nerve stimulation (VNS) is a widely used neuromodulation therapy for LGS, but its effects on seizure outcomes, different seizure types, non-seizure outcomes, and adverse events in this population have not been comprehensively reviewed. To conduct a scoping review on the use of VNS in LGS, a literature search was performed in PubMed, OVID, Web of Science, and Embase from inception to 9 June 2024, using relevant keywords and without restrictions on study design. The search yielded forty eligible studies (twenty-four retrospective cohorts, fourteen prospective cohorts, and two registry analyses) comprising 1400 LGS patients treated with VNS. No randomized controlled trials were identified. Across studies, the median seizure reduction ranged from 20.6% to 65%, with 0% to 100% of patients achieving a ≥50% seizure reduction. No consistent preoperative biomarker of VNS responsiveness was identified in LGS. Although inconsistent among different studies, tonic, atonic, and tonic-clonic seizures responded best, while focal seizures responded worst. Improvements in seizure severity, alertness, and quality of life were reported in some studies, but cognitive and adaptive functioning generally remained unchanged. Adverse events were mostly mild and transient, including hoarseness, cough, and paresthesia. Device-related complications and infections were uncommon. In conclusion, further research is needed to better understand VNS's position in the evolving LGS treatment landscape and its cost effectiveness.

GRIN2A-related epilepsy and speech disorders: A comprehensive overview with a focus on the role of precision therapeutics

Language dysfunction is a common and serious comorbidity of epilepsy, especially in individuals with epilepsy aphasia spectrum syndromes. Childhood epilepsy with centrotemporal spikes is on the mild end of the spectrum, while epileptic encephalopathy with continuous spike-and-wave during sleep syndrome is on the severe end. Traditional antiseizure medicines and immunotherapy are currently used to treat severely affected patients, but the results are usually disappointing. The discovery that GRIN2A is the primary monogenic etiology of these diseases has opened the door to precision treatments. The GRIN2A gene encodes GluN2A protein, which constitutes a subunit of the NMDA receptor (NMDAR). The GRIN2A pathogenic variants cause gain or loss of function of NMDAR; the former can be treated with uncompetitive NMDAR antagonists, such as memantine, while the latter with NMDAR co-agonist serine. Hyper-precision therapies with various other effective agents are likely to be developed shortly to target the diverse functional effects of different variants. Precision treatments for GRIN2A-related disorders will benefit those who suffer from the condition and pave the way for new therapeutic approaches to a variety of other NMDAR-linked neurodegenerative and psychiatric diseases (schizophrenia, Parkinson's disease, Alzheimer's disease, and so on). Furthermore, more research into GRIN2A-related disorders will help us better understand the neuroinflammatory and neuroimmunological basis of epilepsy, as well as the pathological and physiological network activation mechanisms that cause sleep activation of central-temporal spikes and language impairment.

Recent developments in stereo electroencephalography monitoring for epilepsy surgery

Recently the utilization of the stereo electroencephalography (SEEG) method has exploded globally. It is now the preferred method of intracranial monitoring for epilepsy. Since its inception, the basic tenet of the SEEG method remains the same: strategic implantation of intracerebral electrodes based on a hypothesis grounded on anatomo-electroclinical correlation, interpretation of interictal and ictal abnormalities, and formation of a surgical plan based on these data. However, there are recent advancements in all these domains-electrodes implantations, data interpretation, and therapeutic strategy- that can make the SEEG a more accessible and effective approach. In this narrative review, these newer developments are discussed and summarized. Regarding implantation, efficient commercial robotic systems are now increasingly available, which are also more accurate in implanting electrodes. In terms of ictal and interictal abnormalities, newer studies focused on correlating these abnormalities with pathological substrates and surgical outcomes and analyzing high-frequency oscillations and cortical-subcortical connectivity. These abnormalities can now be further quantified using advanced tools (spectrum, spatiotemporal, connectivity analysis, and machine learning algorithms) for objective and efficient interpretation. Another aspect of recent development is renewed interest in SEEG-based electrical stimulation mapping (ESM). The SEEG-ESM has been used in defining epileptogenic networks, mapping eloquent cortex (primarily language), and analyzing cortico-cortical evoked potential. Regarding SEEG-guided direct therapeutic strategy, several clinical studies evaluated the use of radiofrequency thermocoagulation. As the emerging SEEG-based diagnosis and therapeutics are better evolved, treatments aimed at specific epileptogenic networks without compromising the eloquent cortex will become more easily accessible to improve the lives of individuals with drug-resistant epilepsy (DRE).

Fenfluramine: A Review of Pharmacology, Clinical Efficacy, and Safety in Epilepsy

Despite the availability of more than 30 antiseizure medications (ASMs), the proportion of patients who remain refractory to ASMs remains static. Refractory seizures are almost universal in patients with epileptic encephalopathies. Since many of these patients are not candidates for curative surgery, there is always a need for newer ASMs with better efficacy and safety profile. Recently, the anti-obesity medication fenfluramine (FFA) has been successfully repurposed, and various regulatory agencies approved it for seizures associated with Dravet and Lennox–Gastaut syndromes. However, there is a limited in-depth critical review of FFA to facilitate its optimal use in a clinical context. This narrative review discusses and summarizes the antiseizure mechanism of action of FFA, clinical pharmacology, and clinical studies related to epilepsy, focusing on efficacy and adverse effects.

Pharmacotherapeutic management of seizures in patients with Angleman syndrome

Approximately 80-90% of patients with Angelman syndrome (AS) develop childhood-onset intractable seizures with major negative impact on the quality of life.Thus adequate management of seizures is the most critical priority to improve health-related quality of life in children with AS.

AREAS COVERED

The primary focus of the review is on pharmacotherapeutic management of seizures. The first part of the review briefly discusses epileptogenesis and polymorphic seizure phenotypes associated with AS to understand pharmacotherapeutic decision-making better. Next, the review explores individual antiseizure medicines (ASMs) and their potential therapeutic utility. Lastly, some future and emerging treatment options are discussed that can transform the management of seizures in patients with AS.

EXPERT OPINION

Evidence for treating seizures in AS mainly derives from low-quality studies. Levetiracetam and clobazam are the most commonly used ASMs. Although the potential utility of several other ASMs(valproate, topiramate, lamotrigine, ethosuximide, clonazepam) has been well documented for some time, the treatment landscape may rapidly evolve due to the availability of newer and better tolerated ASMs(cannabidiol oil, brivaracetam, perampanel). In addition, a better understanding of the underlying pathogenesis and the development of molecular therapeutics offer hope for precision therapies for seizures.

Conceptualization and implementation of an interdisciplinary clinic for children with drug-resistant epilepsy during the COVID-19 pandemic

OBJECTIVE

To describe the rapid conceptualization and implementation of an interdisciplinary epilepsy clinic for children with drug-resistant epilepsy (DRE) at Arkansas Children's Hospital (ACH) during the COVID 19 pandemic.

METHODS

Focusing on care design and care coordination for children with DRE, multiple stakeholder groups decided to implement a clinic after the systematic rating of constructs present in a theoretical meta-analytic framework. Based on the projected success, the new interdisciplinary clinic (composed of an epileptologist, a neurosurgeon, and a neuropsychologist and coordinated by a full-time nurse) was established. Clinic operations were further refined through discussions with patients, families, and care providers. We collected data retrospectively (August 2020 to June 2021) to determine referral patterns, clinic scheduling metrics, patient characteristics, clinical recommendations, and epilepsy quality metrics.

RESULTS

Of the 32 Consolidated Framework for Implementation Research constructs assessed, 24 were positively rated to predict a high probability of successful implementation of the clinic. For approximately 100 patient visits, appearance and usage rates were >75%, yielding a clinic utilization rate of approximately 60%. Among 76 unique patients (average age of 12 years, 60% focal epilepsy), 39 patients (51.3%) were deemed eligible for epilepsy surgery evaluation. The majority of the patients (53.9%) were advised for additional diagnostic testing, and 31.6% of patients were scheduled for vagus nerve stimulation. More patients (33%) had changes in their existing anti-seizure medication (ASM) regimen rather than an addition of a new ASM (7.9%). Standardized epilepsy quality measures showed >80% to 90% adherence in 3 (reproductive counseling, depression and anxiety screening, documentation of seizure frequency) out of 4 metrics.

SIGNIFICANCE

This is the first study to show that an interdisciplinary clinic can be a valuable attribute of care models in high-need children with DRE by enabling comprehensive one-stop service for diagnostic evaluation, surgical consideration, and brief assessment of psychiatric comorbidities without compromising consensus-based best practices.

Parental experience and decision-making for epilepsy surgery: A systematic review of qualitative and quantitative studies

OBJECTIVE

In selected children with drug-resistant epilepsy (DRE), epilepsy surgery is the most effective treatment option, but unfortunately remains highly underutilized. One of the critical obstacles to pursuing surgical therapy is parents/caregivers' decision against surgery or to delay the surgery until no other treatment option exists. Understanding caregiver decision-making around epilepsy surgery can improve patient/caregiver experience and satisfaction while facilitating appropriate decision-making that optimizes clinical outcomes. The current review systematically explores the existing evidence on caregiver experience and the decision-making process toward epilepsy surgery.

METHODS

The study was conducted as per the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines for systematic literature review. Databases (PubMed Ovid, PubMed Medline, Web of Science, CINHAL, PsycInfo) were systematically searched in February 2021 using a defined search strategy and inclusion/exclusion criteria. Total 1304 articles were screened for titles and abstracts, and 54 full-text articles were retrieved for further assessment. We included 14 articles with critical quality assessment using two different tools for qualitative and questionnaire-based studies. A qualitative content analysis was performed to characterize caregiver experience, perception, and decision-making toward favorable or unfavorable opinions of epilepsy surgery.

RESULTS

Four concepts generated from the analysis may act as enablers or barriers to decision-making around epilepsy surgery: 1. Access to knowledge and information, 2. Communication and coordination issues, 3. Caregiver's emotional state, and 4. Socioeconomic effects. Subsequently, we provided a narrative synthesis of practice recommendations and a conceptual framework to adopt multi-pronged interventions to overcome identified diverse barriers to effective caregiver decision-making.

CONCLUSION

Multiple influences impact how caregivers decide about epilepsy surgery for their children, with no single factor identified as the primary driver for or against surgery. However, limited research has explored these influences. Future studies should focus on quantitatively examining factors to identify significant variables most likely to influence caregiver decision-making, ultimately overcoming barriers that limit utilization of epilepsy surgery as a treatment tool.

Cannabidiol for treatment of refractory childhood epilepsies: Experience from a single tertiary epilepsy center in Slovenia

PURPOSE

Refractory epilepsies in children present a major burden for patients and their families. Cannabidiol (CBD) has been suggested as a potential treatment for refractory epilepsies. The aim of this study was to evaluate the effectiveness of add-on therapy with CBD for the treatment of refractory childhood epilepsies.

METHOD

Patients with childhood-onset refractory epilepsy, treated at the tertiary epilepsy center of the University Children's Hospital Ljubljana, Slovenia, were included in the study. Add-on therapy with CBD was initiated once the child's epilepsy was categorized as pharmacoresistant to other antiepileptic drugs/therapies. The dosage of CBD was gradually increased to at least 8mg/kg/day. The effect of CBD treatment was evaluated by the reduction in seizure burden and presence of side effects (positive and negative). Serial electroencephalography was performed in some children.

RESULTS

Sixty-six patients were included in the analysis. Thirty-two (48.5%) patients had a more than 50% improvement regarding seizure burden, 14 of whom (21.2%) became seizure-free. None of the patients reported worsening of seizure frequency, but CBD had no effect in 15 (22.7%) patients. Some patients reported less vigorous seizures, shorter duration of seizures, shorter time to recovery, and other positive side effects of CBD treatment. Adverse effects were reported in 5/66 children.

CONCLUSIONS

In our cohort of patients, CBD was found to have potential benefits as add-on therapy for refractory childhood epilepsies, mainly by reducing seizure burden.