ILAE Classification of Epilepsy - update

  • View

  • Download

Embed Size (px)


ILAE Classification of Epilepsy - update. Chris Rittey Sheffield. ILAE classification schemes. 1960 first suggested ILAE classification 1981 seizure classification published 1989 syndrome classification published 2001, 2006 attempts at update. 2010. - PowerPoint PPT Presentation


  • ILAE Classification of Epilepsy - updateChris RitteySheffield

  • ILAE classification schemes1960 first suggested ILAE classification1981 seizure classification published1989 syndrome classification published2001, 2006 attempts at update

  • 2010Revised terminology and concepts for organization of the epilepsies: Report of the Commission on Classification and Terminology

    Developed as a methodologically and conceptually sound and meaningful revision to the classifications of 1981 and 1989Based on input from genetics, neuroimaging, therapeutics, paediatric and adult epileptology, statistics, research design

  • What is a classification of epilepsy?A list of entities which are recognised to be distinct forms of epilepsyNo new entities added since 2006 reportThe concepts and structure underpinning that list 1989 classification recognised as an organisation built on concepts rather than true classificationAccordingly the current organisation is being abandonedMechanism and process to determine which entities are included on that list and the features which characterise them this needs to be agreed under new system

  • Changes

  • Seizure classification generalised seizuresConsidered to originate at some point within, and rapidly engage, bilaterally distributed networksNetworks can include cortical and sub-cortical structures but do not necessarily include the entire cortexIndividual seizures may have an apparently localised onset but location and lateralisation are not consistent from one seizure to anotherGeneralised seizures can be asymmetrical

  • Seizure classification- focal seizuresConsidered to originate within networks limited to one hemisphereMay be discretely localised or more widely distributedMay arise in sub-cortical structuresIctal onset is consistent from one seizure to another for each seizure typePreferential propagation patterns occur may involve the contralateral hemisphereThere may be more than one epileptogenic network and more than one seizure type in an individual but each has a consistent site of onset

  • Specific changes to 1981 schemaNeonatal seizures no longer regarded as a separate entity Sub-classification of absences has been simplifiedMyoclonic absence and absence with eyelid myoclonia now recognisedEpileptic spasms included in their own categoryGeneralised, focal, or of unclear onset

  • Specific changes to 1981 schemaDistinction between different types (e.g. simple and complex partial) is eliminated however importance of impairment of consciousness, localisation, ictal progression recognised as potentially important for individual patientsFocal seizures can be described using these conceptsMyoclonic atonic (myoclonic astatic) seizures now recognisedCategory of unclassified epileptic seizures no longer accepted

  • Classification strataClassification of seizuresSyndromes and epilepsiesAetiological designationOther dimensionsIV-A. Age at onsetIV-B. Natural evolutionIV-C. Other features

  • I. Classification of seizuresGENERALISED SEIZURESTonic clonic (in any combination)Absence - typical - atypical - absence with special features - myoclonic absence - eyelid myocloniaMyoclonic - myoclonic - myoclonic atonic - myoclonic tonicClonicTonicAtonicFOCAL SEIZURES


  • Descriptors of focal seizuresWithout impairment of consciousness/responsivenessWith observable motor or autonomic components (corresponds to simple partial seizure)Involving subjective sensory or psychic phenomena only (corresponds to aura)With impairment of consciousness/responsiveness (corresponds to complex partial seizure)Evolving to a bilateral convulsive seizure (involving tonic, clonic or tonic and clonic components) replaces secondary generalised seizure

  • II. Syndromes and epilepsiesNeed to recognise the different levels of specificity between syndromesIn previous classification:Some syndromes very specific and well differentiated e.g. CAEOther syndromes very poorly differentiated e.g. cryptogenic parietal lobe epilepsyNew system attempts to explicitly acknowledge these differences

  • Syndromes will no longer be characterised as being focal or generalised

  • Classification groupsElectroclinical syndromesEpilepsy constellationsEpilepsies secondary to specific structural or metabolic lesions or conditionsEpilepsies of unknown cause

  • Electro-clinical syndromesIComplex of clinical features, signs and symptoms that define a distinctive, recognisable clinical disorderUse of term syndrome will be restricted to a group of clinical entities that are reliably identified by a cluster of electroclinical and developmental relationshipsLargely (not exclusively) geneticTend to have strong relationship to developmental aspects of the brain

  • Electro-clinical syndromesIIIdentifiable on the basis of:Typical age of onsetSpecific EEG characteristicsSpecific seizure types and other clinical featuresDiagnosis has implications for treatment, management and prognosis

  • Epilepsy constellationsEpilepsy entities which are not syndromes per se but represent clinically distinctive collections of featuresOften have implications for treatment, esp. surgicalInclude:Temporal lobe epilepsy (with hippocampal sclerosis)Gelastic seizures with hypothalamic hamartomaRasmussen syndromeAge at presentation is not a defining feature

  • Epilepsies secondary to specific lesions or conditionsLower level of specificity than previous groupsPreviously defined on basis of localisation e.g. symptomatic temporal lobe epilepsyNow recommended that emphasis is placed on the aetiology e.g. epilepsy with focal features secondary to focal cortical dysplasia in the temporal lobeNow included in the classification within the group Structural/metabolic epilepsies

  • Epilepsies of unknown causeIncludes all epilepsies previously known as cryptogenicAccount for 1/3 or more of all people with epilepsyProbably need to move away from attempting to classify by interictal spike focus replace with detailed description of relevant features:Age at onsetEEG featuresCognitive/developmental assessmentDiurnal patterns of seizure occurrenceWill allow improved classification with time

  • Electro-clinical syndromes and other epilepsies Electro-clinical syndromes arranged by age at onset Neonatal period Benign familial neonatal seizures (BFNS) Early myoclonic encephalopathy (EME) Ohtahara syndromeInfancy Migrating partial seizures of infancy West syndrome Myoclonic epilepsy in infancy (MEI) Benign infantile seizures Benign familial infantile seizures Dravet syndrome Myoclonic encephalopathy in nonprogressive disorders

  • Electro-clinical syndromes and other epilepsiesChildhood Febrile seizures plus (FS+) (can start in infancy) Early onset benign childhood occipital epilepsy (Panayiotopoulos type) Epilepsy with myoclonic atonic (previously astatic) seizures Benign epilepsy with centrotemporal spikes (BECTS) Autosomal-dominant nocturnal frontal lobe epilepsy (ADNFLE) Late onset childhood occipital epilepsy (Gastaut type) Epilepsy with myoclonic absences Lennox-Gastaut syndrome Epileptic encephalopathy with continuous spike-and-wave during sleep (CSWS) including: Landau-Kleffner syndrome (LKS) Childhood absence epilepsy (CAE)

  • Electro-clinical syndromes and other epilepsies

    Adolescence - Adult Juvenile absence epilepsy (JAE) Juvenile myoclonic epilepsy (JME) Epilepsy with generalized tonic-clonic seizures alone Progressive myoclonus epilepsies (PME) Autosomal dominant partial epilepsy with auditory features (ADPEAF) Other familial temporal lobe epilepsies

  • Electro-clinical syndromes and other epilepsiesLess Specific Age Relationship Familial focal epilepsy with variable foci (childhood to adult) Reflex epilepsies Distinctive Constellations Mesial temporal lobe epilepsy with hippocampal sclerosis (MTLE with HS) Rasmussen syndrome Gelastic seizures with hypothalamic hamartoma

    Epilepsies that do not fit into any of these diagnostic categories can be distinguished first on the basis of the presence or absence of a known structural or metabolic condition (presumed cause) and then on the basis of the primary mode of seizure onset (generalized versus focal).

  • Electro-clinical syndromes and other epilepsiesEpilepsies attributed to and organized by structural-metabolic causes Malformations of Cortical development (hemimeganencephaly, hetertopias etc) Neurocutaneous syndromes (Tuberous sclerosis complex, Sturge-Weber, etc) Tumor Infection Trauma Angioma Peri-natal insults Stroke Etc.

  • Electro-clinical syndromes and other epilepsies

    Epilepsies of unknown cause

    Conditions with epileptic seizures that are traditionally not diagnosed as a form of epilepsy per se. Benign neonatal seizures (BNS) Febrile seizures (FS)

  • III. Aetiological designationWithdrawal of concepts of idiopathic, cryptogenic and symptomaticThree main aetiological groups:

    Genetic - the epilepsy is the direct result of a known or presumed genetic defect in which seizures are the core symptomStructural/metabolic the epilepsy results from the structural or metabolic condition, not simply as a result of the genetic cause of the conditionUnknown cause

  • IV. Other dimensionsIV-A. Age at onsetNeonatal (< 44 weeks gestational age)Infant (< 2 years)Child (2-12 years)Adolescent (12-18 years)Adult (> 18 years)

  • IV. Other dimensionsIV-B. Natural evolutionEpileptic encephalopathy can be used to characterise syndromes as well as individuals. Need to recognise that source of encephalopathy is usually unknown.Be