Revised terminology and concepts for organization of seizures and epilepsies: Report of the ILAE Commission on Classification and Terminology, 2005–2009

Abstract

Summary The International League Against Epilepsy (ILAE) Commission on Classification and Terminology has revised concepts, terminology, and approaches for classifying seizures and forms of epilepsy. Generalized and focal are redefined for seizures as occurring in and rapidly engaging bilaterally distributed networks (generalized) and within networks limited to one hemisphere and either discretely localized or more widely distributed (focal). Classification of generalized seizures is simplified. No natural classification for focal seizures exists; focal seizures should be described according to their manifestations (e.g., dyscognitive, focal motor). The concepts of generalized and focal do not apply to electroclinical syndromes. Genetic, structural–metabolic, and unknown represent modified concepts to replace idiopathic, symptomatic, and cryptogenic. Not all epilepsies are recognized as electroclinical syndromes. Organization of forms of epilepsy is first by specificity: electroclinical syndromes, nonsyndromic epilepsies with structural–metabolic causes, and epilepsies of unknown cause. Further organization within these divisions can be accomplished in a flexible manner depending on purpose. Natural classes (e.g., specific underlying cause, age at onset, associated seizure type), or pragmatic groupings (e.g., epileptic encephalopathies, self‐limited electroclinical syndromes) may serve as the basis for organizing knowledge about recognized forms of epilepsy and facilitate identification of new forms.

Keywords

Affiliated Institutions

• Great Ormond Street Hospital GB
• The University of Melbourne AU
• University of California, Los Angeles US
• Robert Bosch (Germany) DE
• Stichting Epilepsie Instellingen Nederland NL
• Northwestern Memorial Hospital US
• University College London GB
• Cincinnati Children's Hospital Medical Center US
• Western Infirmary GB
• Hôpital Necker-Enfants Malades FR
• Lurie Children's Hospital US
• Albert Einstein College of Medicine US
• Northern Illinois University US
• New York University US
• Phoenix Children's Hospital US
• Austin Health AU

Related Publications