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ILAE classification of seizures and epilepsy

Christian M Korff, MD
Elaine Wirrell, MD
Section Editors
Timothy A Pedley, MD
Douglas R Nordli, Jr, MD
Deputy Editor
April F Eichler, MD, MPH


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existing International League Against Epilepsy (ILAE) classification systems for seizures and epilepsies have become outdated and inadequate [1,2].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 [3]. 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 and management of the first seizure in adults" and "Seizures and epilepsy in older adults: Etiology, clinical presentation, and diagnosis".)


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) [3].

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.


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Literature review current through: Feb 2017. | This topic last updated: Tue Oct 20 00:00:00 GMT 2015.
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