Download - ILAE Organization of Epilepsies
ILAE Commission for Classification and Terminology
Purpose of the International Classification of Seizures and Epilepsies
To provide a common international terminology and classification
Largely for clinical (treatment) purposes
Purpose of classification: to organize items according to their fundamental relationships
2005-2009 Commission Report,Epilepsia 2010;51:676-685
Main changes, modifications Language and structure for organizing epilepsies
Generalized versus Focal Seizures “Etiology” Diagnostic specificity New recommended terms Organization
NO changes to electroclinical syndromes A diagnosis can be made as previously
eg Lennox-Gastaut syndrome, childhood absence epilepsy A diagnosis is not the same as a classification
Focal reconceptualized
For seizures: Focal epileptic seizures are
conceptualized as originating within networks limited to one hemisphere. These may be discretely localized or more widely distributed.…
Focal seizures Blume et al, Epilepsia 2001
Without impairment of consciousness or awareness Previous term: simple partial With observable motor or autonomic components
eg. focal clonic, autonomic, hemiconvulsive With subjective sensory or psychic phenomena
Aura - specific types
Where alteration of cognition is major feature Previous term: complex partial Dyscognitive
Focal seizures Blume et al, Epilepsia 2001
Evolving to bilateral, convulsive seizure Previous terms: partial seizure secondarily
generalized;secondarily generalized tonic-clonic seizure
With tonic, clonic or tonic and clonic components
Generalized - reconceptualized For seizures
Generalized epileptic seizures are conceptualized as originating at some point within, and rapidly engaging, bilaterally distributed networks. …can include cortical and subcortical structures, but not necessarily include the entire cortex.
Generalized SeizuresTonic-clonic (in any combination)Absence
- Typical - Atypical - Absence with special features
Myoclonic absence Eyelid myocloniaMyoclonic
- Myoclonic- Myoclonic atonic- Myoclonic tonic
ClonicTonic Atonic
Seizure types thought to occur within and result from
rapid engagement of bilaterally distributed systems
Recommended terminology for etiologyUse terms which mean what they
say: Genetic Structural-Metabolic Unknown
Previously used terms denoting old concepts:Idiopathic, cryptogenic, symptomatic
Genetic
Concept: the epilepsy is the direct result of a known or inferred genetic defect(s). Seizures are the core symptom of the disorder.
Evidence: Specific molecular genetic studies (well replicated) or evidence from appropriately designed family studies.
Genetic does not exclude the possibility of environmental factors contributing
Structural-Metabolic
Concept: There is a distinct other structural or metabolic condition or disease present. eg. Tuberous sclerosis
Evidence: Must have demonstrated a substantially increased risk of developing epilepsy in association with the condition.
Unknown
Concept: The nature of the underlying cause is as yet unknown.
New recommended terminology
Previously used terms no longer preferred Classification as focal or generalized epilepsies
not always appropriate use when appropriate
Catastrophic - emotionally laden term Benign - does not recognize that co-morbidities
occur, this term is still used in syndrome names Recommended terms Self-limited: high likelihood of spontaneous
remission Pharmacoresponsive
• New terminology and concepts update the classification to be consistent with current understanding of the epilepsies in clinical practice
• Currently there is no biologically based classification of the epilepsies
• Epilepsies can be organized in a flexible, multidimensional way depending on the purpose
eg. by age, etiology, seizure type, EEG abnormality
Future efforts in classification will depend on a biological mechanisms as these are understood
Future developments in the Classification of the
Epilepsies