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

2. 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

3. 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

4. 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

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

6. Seizure Description
Semiology

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

8. 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

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

10. BY ONSET
Clinical seizure type

11. 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

12. 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.

13. Patient SA
SEMIOLOGY AND CLINICAL SEIZURE TYPE?

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

15. 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

16. Patient TS
SEMIOLOGY AND CLINICAL SEIZURE TYPE?

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

18. Epilepsy classification
LOCALIZATION
ETIOLOGY
SYNDROMES
Epilepsy classification

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

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

21. 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

22. 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

23. 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

24. 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.

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

26. 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”

27. 3 Hz spw

28. 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:
Prognosis: well controlled with little amt of medication. Seizures for life!!!

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

30. BECTS – CT spikes

31. BECTS – CT spikes

32. 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

33. 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

34. 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.

35. 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

36. 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

37. 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 +