Classification of seizures Maysaa Merhi Basha, MD Assistant Professor of Neurology Comprehensive Epilepsy Program WSU/DMC

The Task of Classification ILAE (International League Against Epilepsy) has held several special commissions on seizure classification First efforts: 1960s, 1970s Gastaut, Merlis Current System Framework: 1980s, 1990s Latest update: 2010 Other Influential Figures: Hans Lüders Jerome Engel

Objectives Identify different levels of classification: Semiology: Describe the seizure!!! Clinical Seizure Type by onset (ILAE 2010) Classification of Epilepsy (ILAE 2010): Localization Etiology Generalized Epilepsy and syndromes

Definitions Seizure: ‘‘a transient occurrence of signs and/or symptoms due to abnormal excessive or synchronous neuronal activity in the brain.’’ Fisher et al. 2005 Epilepsy: ONE epileptic seizure with an enduring predisposition for further epileptic seizures Associated cognitive, psychological, and social consequences

Reasons for seizure classification Clinical Management: Indication and utility of AED Epilepsy Surgery Teaching Tool Communication between clinicians Scientific communication Epidemiological studies

Seizure Description Semiology

Semiology Seizure classification based on clinical features 1. Sensory Symptoms (aura) Somatosensory Visual Auditory Gustatory Autonomic Abdominal Psychic Nonspecific

Semiology Seizure classification based on clinical features cont. 2. Motor Symptoms: Motor seizures Tonic Clonic Versive Myoclonic Epileptic Spasm Generalized Tonic-Clonic Automotor seizures (automatism) Hypermotor seizures Gelastic seizure Negative Motor Aphasic seizure Atonic/Astatic Hypomotor

Semiology Seizure classification based on clinical features cont. 3. Consciousness In isolation: Staring, behavioral arrest, unresponsiveness As a modifier of another seizure semiology

BY ONSET Clinical seizure type

Clinical Seizure Type This classification is based on semiology and other diagnostic tests and relevant for: Communication between clinicians Treatment Approach Clinical Seizure type by onset: (ILAE revision 2010) Focal Seizures Without impairment of consciousness/awareness (SPS) With impairment of consciousness/awareness (CPS) Evolving into b/l convulsion (2ndary generalization) Generalized Seizures

Example 1: Patient SA 19 y/o man with episodes of nausea and abdominal discomfort lasting 5 seconds followed by inability to communicate that last for 30 seconds He is unable to speak or text during these episodes.

Patient SA SEMIOLOGY AND CLINICAL SEIZURE TYPE?

Patient SA Focal seizures without impairment of consciousness manifested as Abdominal aura  aphasic seizure

Example 2: Patient TS 36 year old woman complains of right hand tingling that lasts for 15 seconds. She is amnesic of subsequent events She is witnessed to stare off into space with lip smacking and picking movements at her clothes for ~30 seconds Episodes occur 1-2x/week 1x/month she has generalized tonic then clonic movements of all extremities for ~ 1 minute

Patient TS SEMIOLOGY AND CLINICAL SEIZURE TYPE?

Patient TS Focal seizures with impairment of consciousness manifested as Right hand somatosensory aura  automotor seizure with loss of consciousness  secondary generalization

Epilepsy classification LOCALIZATION ETIOLOGY SYNDROMES Epilepsy classification

Epilepsy Classification Classification is based on Semiological seizure type interictal and ictal EEG functional and anatomic neuroimaging Other clinical features Evolution over time

Epilepsy Classification I Localization: Focal: Temporal and Medial Temporal Extratemporal: Frontal, Occipital, Parietal Multifocal Hemispheric Generalized

Epilepsy Classification II Etiology: ILAE 2010 Structural/Metabolic Genetic Unknown No longer use of symptomatic, cryptogenic, idiopathic…. Can be further modified: Structural – post-traumatic Structural – with hippocampal sclerosis Structural – Rasmussen encephalitis

Epilepsy Classification Example 1: Patient SA Seizure Classification: Focal seizures w/o impairment of consciousness manifested as Abdominal aura  aphasic seizure Workup: EEG: interictal and ictal – left temporal lobe MRI: Atrophy and increased signal of hippocampus Classification: Localization: Left temporal lobe epilepsy Etiology: Hippocampal sclerosis

Epilepsy Classification Example 2: Patient TS Seizure Classification: Focal seizures with impairment of consciousness manifested as Right hand somatosensory aura  automotor seizure with loss of consciousness  secondary generalization Workup: EEG: Interical and Ictal: Left posterior quadrant (T5,O1) MRI: normal Classification: Localization: Left parietal lobe epilepsy Etiology: Unknown

Epilepsy Classification III Syndromic Diagnosis Epilepsy defined by electroclinical criteria Complex clinical features, si, sx that together define a distinctive recognizable clinical disorder Typical age of onset Specific EEG characteresitics Specific seizure types Other features Important as these syndromes often carry a specific treatment and prognosis.

Epilepsy Syndromes A. T. Berg et al., Epilepsia 2010 (ILAE classification report)

Absence Staring and transient loss of responsiveness Can be associated with subtle motor symptoms Eye fluttering, myoclonic jerks Short duration (seconds) Normal exam, normal MRI Age of onset: 4- 8 years EEG: 3 Hz Spike-and-wave precipitated by HV Prognosis: Good, typically “outgrown”

3 Hz spw

Juvenile Myoclonic Epilepsy Seizures: Myoclonic jerks of UE (early morning) GTC Staring episodes (1/3rd of patients) Participated by sleep deprivation, alcohol, stress Normal exam, normal mri EEG: 4-6 Hz spike-and-wave activity, reactive to photic stimulation Age of onset: 12- 18 Prognosis: well controlled with little amt of medication. Seizures for life!!!

Benign Epilepsy with Centrotemporal Spikes (BECTS) Brief hemifacial motor seizures Facial twitching, tongue numbness Nocturnal Occasional generalization Age of onset: 3- 13 years; Boys > girls Normal exam, normal imaging EEG: Centrotemporal spikes that occur in runs during sleep Prognosis: remission > 90% by mid-teens

BECTS – CT spikes

BECTS – CT spikes

Lennox Gastaut Syndrome Triad Multiple seizure types: atonic, tonic, atypical absence…etc..) Mental Retardation EEG: Slow-spike-and wave (1-2.5 Hz), Multifocal spikes also seen Prognosis: poor, intractable epilepsy, encephalopathy

Febrile Seizures Plus Persistence of febrile seizures beyond 6 years of age Associated non-febrile GTCS Family history of epilepsy Other syndromes, Dravet, Doose AD Mutation in sodium channel and GABA subunit gene SCN1A, SCN1B, SCN2A, GABARG2 Prognosis: seizure resolution by mid- adolescence; some with onset of different type of seizures many years later

Example 3: Patient MA 17 year old with witnessed generalized tonic clonic seizures by his parents, after he drove home in the middle of the night from Chicago He is amnesic of the episode He also complains of objects flying from his hand early in the morning for the past couple of months. EEG shows generalized 5 Hz spike and wave and polyspike activity.

Patient MA Semiology: Clinical Seizure Type: Generalized onset Myoclonic seizure Generalized Tonic-clonic seizure Clinical Seizure Type: Generalized onset Epilepsy Classification: Localization: Generalized Etiology: Unknown Syndrome: JME

Example 4: Patient KM 7 year old who has febrile seizures since age 1 and continues to have them. Dad also had febrile seizures as a child. EEG is normal

Patient KM Semiology: Clinical Seizure Type: Generalized onset Generalized Tonic-clonic seizure Clinical Seizure Type: Generalized onset Epilepsy Classification: Localization: Generalized Etiology: Genetic Syndrome: FB +