Mechanism 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
Considered to originate at some point within, and rapidly engage, bilaterally distributed networks
Considered to originate at some point within, and rapidly engage, bilaterally distributed networks
Networks can include cortical and sub-cortical structures but do not necessarily include the entire cortex
Individual seizures may have an apparently localised onset but location and lateralisation are not consistent from one seizure to another
Generalised seizures can be asymmetrical
Considered to originate within networks limited to one hemisphere
Considered to originate within networks limited to one hemisphere
May be discretely localised or more widely distributed
May arise in sub-cortical structures
Ictal onset is consistent from one seizure to another for each seizure type
Preferential propagation patterns occur – may involve the contralateral hemisphere
There may be more than one epileptogenic network and more than one seizure type in an individual but each has a consistent site of onset
Neonatal seizures no longer regarded as a separate entity
Neonatal seizures no longer regarded as a separate entity
Sub-classification of absences has been simplified
Myoclonic absence and absence with eyelid myoclonia now recognised
Epileptic spasms included in their own category
Generalised, focal, or of unclear onset
Distinction 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 patients
Distinction 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 patients
Focal seizures can be described using these concepts
Myoclonic atonic (myoclonic astatic) seizures now recognised
Category of unclassified epileptic seizures no longer accepted
Need to recognise the different levels of specificity between syndromes
In previous classification:
Some syndromes very specific and well differentiated e.g. CAE
Other syndromes very poorly differentiated e.g. cryptogenic parietal lobe epilepsy
New system attempts to explicitly acknowledge these differences
Syndromes will no longer be characterised as being focal or generalised
Electroclinical syndromes
Electroclinical syndromes
Epilepsy constellations
Epilepsies secondary to specific structural or metabolic lesions or conditions
Epilepsies of unknown cause
Complex of clinical features, signs and symptoms that define a distinctive, recognisable clinical disorder
Complex of clinical features, signs and symptoms that define a distinctive, recognisable clinical disorder
Use of term “syndrome” will be restricted to a group of clinical entities that are reliably identified by a cluster of electroclinical and developmental relationships
Now recommended that emphasis is placed on the aetiology e.g. epilepsy with focal features secondary to focal cortical dysplasia in the temporal lobe
Now included in the classification within the group “Structural/metabolic epilepsies”
Includes all epilepsies previously known as cryptogenic
Includes all epilepsies previously known as cryptogenic
Account for 1/3 or more of all people with epilepsy
Probably need to move away from attempting to classify by interictal spike focus – replace with detailed description of relevant features:
Age at onset
EEG features
Cognitive/developmental assessment
Diurnal patterns of seizure occurrence
Will allow improved classification with time
Electro-clinical syndromes arranged by age at onset
Electro-clinical syndromes arranged by age at onset
Neonatal period Benign familial neonatal seizures (BFNS) Early myoclonic encephalopathy (EME) Ohtahara syndrome
Infancy 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
Childhood 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)
Childhood 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)
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
Less Specific Age Relationship Familial focal epilepsy with variable foci (childhood to adult) Reflex epilepsies
Less 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).
Epilepsies attributed to and organized by structural-metabolic causes
Epilepsies 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.
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)
Withdrawal of concepts of idiopathic, cryptogenic and symptomatic
Withdrawal of concepts of idiopathic, cryptogenic and symptomatic
Three main aetiological groups:
Genetic - the epilepsy is the direct result of a known or presumed genetic defect in which seizures are the core symptom
Structural/metabolic – the epilepsy results from the structural or metabolic condition, not simply as a result of the genetic cause of the condition
Unknown cause
IV-A. Age at onset
IV-A. Age at onset
Neonatal (< 44 weeks gestational age)
Infant (< 2 years)
Child (2-12 years)
Adolescent (12-18 years)
Adult (> 18 years)
IV-B. Natural evolution
IV-B. Natural evolution
Epileptic encephalopathy – can be used to characterise syndromes as well as individuals. Need to recognise that source of encephalopathy is usually unknown.
‘Benign’ – key features
Seizures are self-limited i.e. spontaneous remission, regardless of treatment, occurs at an expected age and is the anticipated outcome
Seizures themselves are not disabling over the course of the active epilepsy – does not preclude subtle/moderate cognitive and behavioural consequences
No single specific organisation proposed for this classification
Individual epilepsy entities (regardless of specificity) should be organised as most relevant for the individual
May follow the same process used in 1989 classification, or a completely different set of criteria depending on their fitness for purpose e.g. according to specific underlying cause or lesion
New proposed classification is recognised to be an evolutionary process
New proposed classification is recognised to be an evolutionary process
Several specific changes e.g. related to seizure classification, ‘electro-clinical syndromes’
No ‘designated’ system for organising the classification – clinicians will need to determine most appropriate structure for individual patients
Current classification reflects current state of knowledge
