ILAE classification of seizures and epilepsy
- Christian M Korff, MD
Christian M Korff, MD
- Head, Pediatric Neurology
- Geneva University Hospitals
- Elaine Wirrell, MD
Elaine Wirrell, MD
- Professor of Neurology and Director of Pediatric Epilepsy
- Mayo Clinic
- Section Editors
- Timothy A Pedley, MD
Timothy A Pedley, MD
- Editor-in-Chief — Neurology
- Section Editor — Epilepsy
- Henry and Lucy Moses Professor of Neurology
- Columbia University College of Physicians and Surgeons
- Douglas R Nordli, Jr, MD
Douglas R Nordli, Jr, MD
- Section Editor — Pediatric Neurology
- Chief of Neurology
- Children’s Hospital Los Angeles
- Vice Chair of Neurology
- USC Keck School of Medicine
Over the past several decades, significant advances in neuroimaging, genomic technologies, and molecular biology have improved the understanding of the pathogenesis of seizures and epilepsy. In addition, many epilepsy syndromes have been delineated. As a result, existing International League Against Epilepsy (ILAE) classification systems for seizures and epilepsies have become outdated and inadequate [1,2].
The ILAE Commission on Classification and Terminology released a revision of the former system in 2010 . The report is not a new classification system, but rather uses a new set of concepts to organize current knowledge. The scheme is considered a mechanism for the continuing process of achieving a more scientifically exact classification.
The most important concepts developed in the latest ILAE proposal are described here. The evaluation and diagnosis of seizures and epilepsy in children and adults are discussed separately. (See "Clinical and laboratory diagnosis of seizures in infants and children" and "Seizures and epilepsy in children: Classification, etiology, and clinical features" and "Epilepsy syndromes in children" and "Evaluation of the first seizure in adults" and "Seizures and epilepsy in older adults: Etiology, clinical presentation, and diagnosis".)
MODE OF SEIZURE ONSET
In previous classifications, seizures were dichotomized into partial or generalized [1,2]. This classification was inadequate for certain seizure types, such as spasms, which may appear generalized, despite being caused by a focal lesion. In the 2010 proposal, mode of onset is subdivided into generalized, focal, and unknown, the latter of which includes spasms (table 1) .
Generalized — Generalized seizures are conceptualized as those that originate at some point within, and rapidly engage bilaterally distributed networks, which can be subcortical or cortical structures. Generalized seizures do not need to necessarily include the entire cortex, however, and they may be asymmetric. Importantly, a generalized presentation can still arise from a focal lesion, and does not exclude the possibility of a surgical remedy.
- Proposal for revised clinical and electroencephalographic classification of epileptic seizures. From the Commission on Classification and Terminology of the International League Against Epilepsy. Epilepsia 1981; 22:489.
- Proposal for revised classification of epilepsies and epileptic syndromes. Commission on Classification and Terminology of the International League Against Epilepsy. Epilepsia 1989; 30:389.
- Berg AT, Berkovic SF, Brodie MJ, et al. Revised terminology and concepts for organization of seizures and epilepsies: report of the ILAE Commission on Classification and Terminology, 2005-2009. Epilepsia 2010; 51:676.
- Blume WT, Lüders HO, Mizrahi E, et al. Glossary of descriptive terminology for ictal semiology: report of the ILAE task force on classification and terminology. Epilepsia 2001; 42:1212.