ILAE classification of the epilepsies: Position paper of the ILAE Commission for Classification and Terminology

Abstract

Summary The ILAE Classification of the Epilepsies has been updated to reflect our gain in understanding of the epilepsies and their underlying mechanisms following the major scientific advances which have taken place since the last ratified classification in 1989. As a critical tool for the practising clinician, epilepsy classification must be relevant and dynamic to changes in thinking, yet robust and translatable to all areas of the globe. Its primary purpose is for diagnosis of patients, but it is also critical for epilepsy research, development of antiepileptic therapies and communication around the world. The new classification originates from a draft document submitted for public comments in 2013 which was revised to incorporate extensive feedback from the international epilepsy community over several rounds of consultation. It presents three levels, starting with seizure type where it assumes that the patient is having epileptic seizures as defined by the new 2017 ILAE Seizure Classification. After diagnosis of the seizure type, the next step is diagnosis of epilepsy type, including focal epilepsy, generalized epilepsy, combined generalized and focal epilepsy, and also an unknown epilepsy group. The third level is that of epilepsy syndrome where a specific syndromic diagnosis can be made. The new classification incorporates etiology along each stage, emphasizing the need to consider etiology at each step of diagnosis as it often carries significant treatment implications. Etiology is broken into six subgroups, selected because of their potential therapeutic consequences. New terminology is introduced such as developmental and epileptic encephalopathy. The term benign is replaced by the terms self-limited and pharmacoresponsive, to be used where appropriate. It is hoped that this new framework will assist in improving epilepsy care and research in the 21st century.

Depdc5 knockdown causes mTOR‐dependent motor hyperactivity in zebrafish

“…Focal seizures, which originate within neuronal networks limited to one brain hemisphere,1 are the most frequent epilepsies. In 2013, the discovery of mutations in the negative regulator of mTOR complex 1 (mTORC1), DEPDC5 (DEP domain containing protein 5) in autosomal‐dominant familial focal epilepsy has open novel perspectives in the field 2, 3…”

Thalamic volume reduction in drug‐naive patients with new‐onset genetic generalized epilepsy

“…People with genetic generalized epilepsy (GGE) are expected to have normal neuroimaging findings when studied with a conventional clinical magnetic resonance imaging (MRI) scan 1, 2. However, subtle abnormalities of brain morphology have frequently been reported.…”

De Novo Mutations in YWHAG Cause Early-Onset Epilepsy

“…1 There are currently 51 established EE-associated genes, in which many causal mutations arise de novo. [2][3][4][5][6][7][8][9][10][11][12][13] However, with the advent of high-throughput sequencing, an increasing number of candidate genes are emerging with only a single reported de novo variant.…”

“…Seizure types and electroclinical syndromes were classified according to the International League Against Epilepsy (ILAE). 1 Individuals with self-limiting benign electroclinical syndromes, such as childhood absence epilepsy (onset > 4 years), were excluded on the basis of its more likely multifactorial inheritance. Individuals were identified to have an epileptic encephalopathy if the epileptic activity itself was determined to or was at risk of (e.g., new onset of infantile spasms) contributing to severe cognitive and behavioral impairments above and beyond what might be expected from the underlying pathology alone.…”

“…Individuals were identified to have an epileptic encephalopathy if the epileptic activity itself was determined to or was at risk of (e.g., new onset of infantile spasms) contributing to severe cognitive and behavioral impairments above and beyond what might be expected from the underlying pathology alone. 1 The average age of seizure onset for the 42 selected EE subjects was 20.6 5 18.9 months (1 week to 5 years). Focal seizures with impaired awareness were the most common seizure type (20 subjects [47.6%]), followed by generalized myoclonic seizures (16 subjects [40%]).…”