Classification of epilepsies and seizures: historical perspective and future directions

The Relationship between Muscarinic and Cannabinoid Receptors in Neuronal Excitability and Epilepsy: A Review

Background

Of the seventy million people who suffer from epilepsy, 40 percent of them become resistant to more than one antiepileptic medication and have a higher chance of death. While the classical definition of epilepsy was due to the imbalance between excitatory glutamatergic and inhibitory γ-aminobutyric acid (GABA)-ergic signalling, substantial evidence implicates muscarinic receptors in the regulation of neural excitability.

Summary

Cannabinoids have shown to reduce seizure activity and neuronal excitability in several epileptic models through the activation of muscarinic receptors with drugs which modulate their activity. Cannabinoids also have been effective in reducing antiepileptic activity in pharmaco-resistant individuals; however, the mechanism of its effects in temporal lobe epilepsy is not clear.

Key Messages

This review seeks to elucidate the relationship between muscarinic and cannabinoid receptors in epilepsy and neural excitability.

Length Polymorphism and Methylation Status of UPS29 Minisatellite of the ACAP3 Gene as Molecular Biomarker of Epilepsy. Sex Differences in Seizure Types and Symptoms

Epilepsy is a neurological disease with different clinical forms and inter-individuals heterogeneity, which may be associated with genetic and/or epigenetic polymorphisms of tandem-repeated noncoding DNA. These polymorphisms may serve as predictive biomarkers of various forms of epilepsy. ACAP3 is the protein regulating morphogenesis of neurons and neuronal migration and is an integral component of important signaling pathways. This study aimed to carry out an association analysis of the length polymorphism and DNA methylation of the UPS29 minisatellite of the ACAP3 gene in patients with epilepsy. We revealed an association of short UPS29 alleles with increased risk of development of symptomatic and cryptogenic epilepsy in women, and also with cerebrovascular pathologies, structural changes in the brain, neurological status, and the clinical pattern of seizures in both women and men. The increase of frequency of hypomethylated UPS29 alleles in men with symptomatic epilepsy, and in women with both symptomatic and cryptogenic epilepsy was observed. For patients with hypomethylated UPS29 alleles, we also observed structural changes in the brain, neurological status, and the clinical pattern of seizures. These associations had sex-specific nature similar to a genetic association. In contrast with length polymorphism epigenetic changes affected predominantly the long UPS29 allele. We suppose that genetic and epigenetic alterations UPS29 can modify ACAP3 expression and thereby affect the development and clinical course of epilepsy.

Getting serious about the early-life epilepsies

Early-life epilepsies represent a group of many individually rare and often complex developmental brain disorders associated with lifelong devastating consequences and high risk for early mortality. The quantity and quality of evidence needed to guide the evaluation and treatment to optimize outcomes of affected children is minimal; most children are treated within an evidence-free practice zone based solely on anecdote and lore. The remarkable advances in diagnostics and therapeutics are implemented haphazardly with no systematic effort to understand their effects and value. This stands in stark contrast to the evidence-rich practice of the Children's Oncology Group, where standard of care treatments are identified through rigorous, multicenter research studies, and the vast majority of patients are treated on protocols developed from that research. As a consequence, overall mortality for childhood cancers has declined from ∼90% in the 1950s to ∼20% today. The situations of these 2 rare disease specialties are contrasted, and some suggestions for moving early-life epilepsy onto a fast track for success are offered. Chief amongst these is that early-life epilepsy should be treated with the same urgency as pediatric cancer. The best diagnostics and evidence-based treatments should be used in a systematic fashion right from the start, not after the child and family have been subjected to the ravages of the disorder for months or years. This will require unity and cooperation among physicians, researchers, and institutions across state and national borders.

Epilepsy in mucopolysaccharidosis disorders

The mucopolysaccharidosis (MPS) disorders are caused by deficiencies of specific lysosomal enzymes involved in the catabolism of glycosaminoglycans (GAGs). The resulting GAG accumulation in cells and tissues throughout the body leads to progressive multi-organ dysfunction. MPS patients present with several somatic manifestations, including short stature, musculoskeletal abnormalities, and cardiorespiratory dysfunction, and several primary and secondary neurological signs and symptoms. Epileptic seizures are neurological signs of MPS thought to develop due to accumulation of GAGs in the brain, triggering alterations in neuronal connectivity and signaling, and release of inflammatory mediators. The amount of literature on the prevalence, pathophysiology, clinical features, and management of epileptic seizures in patients with MPS is limited. This review discusses current knowledge on this topic, as well as two case examples, presented and discussed during a closed meeting on MPS and the brain among an international group of experts with extensive experience in managing and treating MPS.

Early Life Epilepsies are a Comorbidity of Developmental Brain Disorders

Early-life epilepsies are a series of disorders frequently accompanied by a broad range of morbidities that include cognitive, behavioral, neuromuscular, and sleep disturbances; enteric and other forms of autonomic dysfunction; sensory processing difficulties; and other issues. Usually these morbidities cluster together in a single patient. Rather than these being separate conditions, all, including the seizures, are manifestations or coexpressions of developmental brain disorders. Instead of viewing epilepsy as the disease and the other features as comorbidities, approaching early-life epilepsies as part of the spectrum of developmental brain disorders could have implications for multidisciplinary care models, anticipatory guidance, and counseling of parents, as well as the design of randomized trials and targeting important outcomes. Ultimately, such an approach could improve understanding and help optimize outcomes in these difficult to treat disorders of early childhood.

Type and etiology of pediatric epilepsy in Jordan. A multi-center study

OBJECTIVE

To study types and etiologies of epilepsy in Jordanian pediatric epileptic patients maintained on antiepileptic drugs using customized classification scheme of International League Against Epilepsy (ILAE) (2010) report.

METHODS

This is a cross-sectional, multi-centre study on pediatric epileptic patients on antiepileptic drugs, who were managed in the pediatric neurology clinics at 6 teaching public hospitals in Jordan.

RESULTS

Out of the 663 patients included in the study, (90.2%) had one seizure type, (53%) of this type were focal seizures followed by generalized seizures (41.5%) and spasms (5.5%). Distinctive constellations were found in 11/663 (1.7%) patients. Benign epilepsies with centrotemporal spikes were the most common electro clinical syndromes 60/221 (27.1%). Epilepsies attributed to structural-metabolic causes were documented in 278/663 (41.9%) patients, unknown causes 268/663(40.4%) and genetic causes in 117/663(17.7%). Most common causes of structural-metabolic group were due to perinatal insults (32%) and most common causes of the genetic group were the presumed genetic electro clinical syndromes (93.1%).

CONCLUSION

Our study is on pediatric epilepsy, using customized classification scheme from the ILAE 2010 report which showed interesting results about type and etiology of epileptic seizures from developing country with potential impact on the international level.

Comparison of ILAE 2010 and semiological seizure classification in children with epilepsy

OBJECTIVE

The aim of this study was to compare both ILAE 2010 and semiological seizure classification (SSC) in terms of their applicability and utility and to predict epileptogenic zone in children with epilepsy.

METHODS

Both ILAE 2010 classification and SSC which is a part of five dimensional classification were applied for a total 138 children by dividing into younger (≤6y/o) and older (>6y/o) age groups over the last two years as retrospectively. After the assessment of the seizures types, epilepsy syndromes, and etiologies; the data were also compared to evaluate if having correlation between epileptogenic zone and seizure subtypes in both ILAE 2010 and SSC.

RESULTS

ILAE 2010 indicated that 66.7% of the patients had focal seizures, 15.9% had generalized seizures, and 14.4% had seizures of unknown origin. The SSC revealed that the most frequent seizure type was simple seizures (56.5%), second frequent one was complex motor seizures (46.4%) and dialeptic seizures (39.9%). To predict epileptogenic zone, SSC was found to be more specific than ILAE in terms of the more subgroups of SSC were related to the more subgroups of epileptogenic zone (p<0.05). Furthermore, there was a clear correlation between focal foci and specific seizure types in older ages, while many foci caused to same seizure types and tend to no clear focal foci with generalized onset in younger ages. On the other hand, the relationship between epileptogenic zone and etiology was more remarkable in the five dimensional classification.

SIGNIFICANCE

Preference of seizure classification system is unique for each patient and depends on requirements. Therefore, one dimension cannot be sufficient for evaluation the nature of the seizures in some patients. Furthermore, age related evolution of the seizure types should not be ignored due to ongoing maturation state of the brain. ILAE 2010 and SSC have weak and strong points compared to each other. Semiological seizure classification is more informative in terms of identifying the epileptogenic zone which may be important in specific occasions like pre-surgical work up, while ILAE is simple and easier method which can be applied for seizure description and their characteristics in daily practice.

Status epilepticus: Using antioxidant agents as alternative therapies

The epileptic state, or status epilepticus (SE), is the most serious situation manifested by individuals with epilepsy, and SE events can lead to neuronal damage. An understanding of the molecular, biochemical and physiopathological mechanisms involved in this type of neurological disease will enable the identification of specific central targets, through which novel agents may act and be useful as SE therapies. Currently, studies have focused on the association between oxidative stress and SE, the most severe epileptic condition. A number of these studies have suggested the use of antioxidant compounds as alternative therapies or adjuvant treatments for the epileptic state.

Moving into the wide clinical spectrum of consciousness disorders: Pearls, perils and pitfalls

The last few years have been characterized by a growing interest of the medical and scientific world for the field of consciousness and its related disorders. Medically speaking, consciousness can be defined as the state of awareness of self and environment and the alertness to external stimulation, besides responsiveness to inner need. Transient loss of consciousness can be due to alterations in cerebral blood flow leading to fainting or syncope, migraine, metabolic dysfunctions, unexpected intracranial pressure increases, epileptic seizures, and sleep disorders. Chronic disorders of consciousness are a tragic success of high-technology treatment, in an attempt to maintain or reestablish brain function, which is to be considered as the main goal of therapeutics. Management of vegetative or a minimally conscious state individuals involves charily getting the right diagnosis with an evidence-based prognosis, also taking into account the medical, ethical, and legal key factors of the ideal treatment. This paper is aimed at exploring the wide spectrum of consciousness disorders and their clinical differential diagnosis, with particular regards to those with a negative impact on patient and their caregiver quality of life, including epilepsy, sleep disorders, and vegetative/minimally conscious state.

Genetic epilepsies. Remarks on the proposed “Organization of the Epilepsies”

Introduction.Genetic findings in several epilepsy syndromes provide insights into the pathophysiology of specific subtypes of epilepsy and into mechanisms of epileptogenesis, because the genes encoding ion channels, and proteins associated to the vesical synaptic cycle, or involved in energy metabolism, influence neuronal excitability.

Aim.The following aspects of genetic epilepsies will be discussed: new proposed “organization of the epilepsies”, genetic and other etiologies, electroclinical syndromes and their genetics and genetic testing in the epilepsies.

Methods.The updated review is based on OMIM™ (Online Mendelian Inheritance in Man).

Review and remarks.Because of the vast genetic and phenotypic heterogeneity, bridging genotype and phenotype remains a major challenge in epilepsy genetics. The so-called “idiopathic” epilepsies are genetically determined. The new ILAE proposal on the “organization” of the epilepsies takes into account the genetic advances. However, despite proposed changes in the nomenclature, the concept of the electroclinical syndrome, i.e. seizure types, age-dependent onset, electroencephalographic criteria, and concomitant symptoms, such as movement disorders or developmental delay, remain important criteria to group the epilepsies. Although also the differentiation “generalized” versus “focal” is nowadays discussed critically, for practical reasons these categories remain valid. Similarly the categories “benign” syndromes of early childhood, epileptic encephalopathies, and fever-associated syndromes, have their utility.

Conclusions.The large number of genetic defects in the epilepsies complicates their analysis. However, it is anticipated that novel genetic methods, that are able to analyze all known genes at a reasonable price, will help identify novel diagnostic and therapeutic avenues, including prognostic and genetic counseling. Today it is already possible to include into genetic testing genes responsible for the side effects of AEDs. In addition, for some epilepsy phenotypes it has became possible to predict the most efficacious antiepileptic drugs for patients based on their genetic makeup. Thus, the development of individualized medicine is expected to greatly improve the management of epilepsy patients.

Priorities in pediatric epilepsy research: improving children's futures today

The Priorities in Pediatric Epilepsy Research workshop was held in the spirit of patient-centered and patient-driven mandates for developing best practices in care, particularly for epilepsy beginning under age 3 years. The workshop brought together parents, representatives of voluntary advocacy organizations, physicians, allied health professionals, researchers, and administrators to identify priority areas for pediatric epilepsy care and research including implementation and testing of interventions designed to improve care processes and outcomes. Priorities highlighted were 1) patient outcomes, especially seizure control but also behavioral, academic, and social functioning; 2) early and accurate diagnosis and optimal treatment; 3) role and involvement of parents (communication and shared decision-making); and 4) integration of school and community organizations with epilepsy care delivery. Key factors influencing pediatric epilepsy care included the child's impairments and seizure presentation, parents, providers, the health care system, and community systems. Care was represented as a sequential process from initial onset of seizures to referral for comprehensive evaluation when needed. We considered an alternative model in which comprehensive care would be utilized from onset, proactively, rather than reactively after pharmacoresistance became obvious. Barriers, including limited levels of evidence about many aspects of diagnosis and management, access to care--particularly epilepsy specialty and behavioral health care--and implementation, were identified. Progress hinges on coordinated research efforts that systematically address gaps in knowledge and overcoming barriers to access and implementation. The stakes are considerable, and the potential benefits for reduced burden of refractory epilepsy and lifelong disabilities may be enormous.

Role of oxidative stress in refractory epilepsy: evidence in patients and experimental models

Oxidative stress, a state of imbalance in the production of reactive oxygen species and nitrogen, is induced by a wide variety of factors. This biochemical state is associated with systemic diseases, and diseases affecting the central nervous system. Epilepsy is a chronic neurological disorder with refractoriness to drug therapy at about 30%. Currently, experimental evidence supports the involvement of oxidative stress in seizures, in the process of their generation, and in the mechanisms associated with refractoriness to drug therapy. Hence, the aim of this review is to present information in order to facilitate the handling of this evidence and determine the therapeutic impact of the biochemical status for this pathology.