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1. EPILEPTIC ENCEPHALOPATHIES-
EEG
Dr. RAVI GOYAL
SR NEUROLOGY
GMC, KOTA

2. 1 month old girl with tonic seizure and right frontal cortical
dysplasia
OHTAHARA syndrome- asymmetrical(R>L) high amplitude burst(3-4 sec)-
suppresion(2-3sec) pattern

3. EARLY INFANTILE EPILEPTIC ENCEPHALOPATHY
(EIEE)/ OHTAHARA SYNDROME
• Neonatal onset 10 days to 3 months of age.
• Most common cause- Static structural brain damage .
• Mc seizure -Tonic spasm either Generalized or Lateralized.
• EEG – Burst Suppression pattern with high voltage Paroxysmal spike/
poly-spike discharges for Up to 3-6 seconds f/b prolonged periods of
nearly flat tracing for up to 2-5 seconds.
• Unchanged during wakefulness and sleep.
• May progress to west (in75%) or Lennox-Gastaut syndrome despite
treatment.

4. A neonate p/w focal myoclonic jerks
Early myoclonic encephalopathy-suppression (5-6sec)-burst (2-3sec)
pattern

5. EARLY MYOCLONIC ENCEPHALOPATHY
• Neonatal period up to 3 months.
• Focal myoclonus of the face or extremities with random
migration from one part to another.(erratic or fragmentary)
• Mc causes- inborn error of metabolism(nonketotic
hyperglycinemia)
• EEG – Suppression Burst Pattern
• The bursts last for 1–5 seconds with longer periods of
suppression (3–10 seconds) .
• More prominent during the sleep and shorter burst duration
• Poor prognosis (>50% die before 1 yr of age )

6. OHTAHARA SYNDROME
• Burst phase is longer than
suppression phase.
• Burst- burst interval is
almost regular.
• EEG changes in sleep as well
as awake states.
• Burst suppression pattern
disappear within 2-3
months & replaced by
hypsarrhythmia.
EARLY MYOCLONIC
ENCEPHALOPATHY
• suppression phase is longer
than Burst phase.
• Burst- burst interval is
variable.
• EEG changes enhanced in
sleep states.
• Remains for longer time

7. A 4 month old baby p/w infantile spasm
West syndrome. Hypsarrythmic background with high amplitude poorly organized chaotic
appearing brain waves. A synchronous slow wave correlates with his clinical spasm (arrow)
and is followed by electrodecrement

8. West syndrome
• Onset - age of 3 and 12 months.
• Triad of infantile spasms, arrest of psychomotor development and
hypsarrhythmia
• Interictal EEG- hypsarrhythmic pattern- disorganised, chaotic,
asynchronous, very high amplitude slowing and frequent multifocal
spikes and sharp wave discharges.
• This pattern gradually becomes more organized, fragmented and
disappears by the age of 2 years & replaced by slow GSWD pattern of
LGS in 60% of patients.
• Better seen in NREM sleep, in awake state more synchronous and
relative normalization in REM sleep.

9. 17 month old child with h/o febrile seizure p/w myoclonic jerks
Dravet syndrome- at awakening, brief burst of sharp waves induced by opening
and closing of eye during crying. During sleep recurrences of diffuse sharp wave
discharges

10. Dravet syndrome(severe myoclonic
epilepsy in infancy)
• Onset - always < 1yr of life
• Presented with -
• Early onset infantile febrile clonic seizures, Myoclonic jerks
• Atypical absences and Complex partial seizures.
• Cognitive and neurological deterioration
• Inter-ictal EEG-
• Early stage (<1yr)- background normal with theta activity
• 25% cases generalised spike or poly spike by photic stimulation.
• Intermediate (2-5 yr)- slowing in background in 50% cases with
generalised fast spike or poly spike discharges.

11. • Late stage (>5-6yr)-multifocal spikes or sharp wave discharges
with back ground slowing.
• Photic stimulation and sleep activation precipitate spike and
wave discharges.
• Precipitated by fever, hot bath and warm environment.
• SCN1A mutations are found in 80% of patients with Dravet
syndrome.

12. 3yr old child p/w multiple drop attacks
LGS- EEG shows the characteristic slow 1.5–2 Hz spike and wave or sharp and wave
(arrows) pattern in LGS.

13. LENNOX- GASTAUT SYNDROME
• Onset -1–7 years , peak 3–5 years
• Multiple seizure types, mainly tonic (most common), atonic,
absence.
• Mental retardation or regression.
• Inter-ictal EEG –
• Generalised slow (2.5Hz) spike and wave discharges (GSWD) and
paroxysm of fast activity (10 Hz or more) in NREM sleep are
characteristic.
• Hyperventilation may facilitate GSWD and atypical absences.

14. • Ictal EEG –
• Tonic – paroxysmal fast activity, which is bilateral and often
predominates in the anterior regions of brain and vertex.
• Atonic – Gen. poly spikes or GSWD
• Atypical absence - <2.5Hz GSWD
• Myoclonic – Gen. polyspikes with or without slow waves.
• Post ictaly- there is diffuse slowing or slow GSWD.
• Refractory to conventional AED’S.

15. 3yr old child p/w myoclonic jerk f/b atonic seizures
Doose syndrome- Generalised spike-wave discharges on normal background(>3Hz)

16. EPILEPSY WITH MYOCLONIC – ASTATIC
SEIZURE(EM-AS)
(DOOSE SYNDROME)
• Normal development prior to onset of seizure.
• Onset of Myoclonic, Myoclonic Atonic or Atonic seizures
between the age group of 1 and 6 yrs.
• No tonic seizures
• Normal EEG background with generalized spike / Poly spike
discharges at 3- 7Hz with Photosensitivity.
• Variable prognosis (50% recovers)

18. 5 year old child p/w behavioral problem, developmental regression
and partial motor seizures
CSWS- spike and wave disharges mainly in fronto-temporal or centro
temporal areas (anterior predominance)

19. CONTINUOUS SPIKE AND WAVE DURING
SLEEP(CSWS)
• Age of onset 2-12 years, peak 4-5 years.
Triad consists of-
1. Intractable seizures- unilateral,tonic-clonic or clonic
2. Inter ictal Epileptiform Activity that becomes prominent during
sleep (NREM), leading to EEG pattern of Electrical Status Epilepticus
in sleep (ESES) or CSWS (mainly in fronto-temporal or centro-
temporal areas)
3. Neurocognitive Regression .

20. Early stage (before CSWS)-
• Seizure with normal development
• EEG- focal spikes and bisynchronous generalised slow-spike or sharp
wave discharges
Active stage-
• Typical CSWS pattern appears on EEG 1-2 years after the first
seizures
• Children with Frontal CSWS – Aggressiveness/ Disinhibition/
Inattention
• Children with Temporal CSWS- Expressive Aphasia with Non fluent
speech
Remission stage-
• After 3- 8 years of age seizures remit in all cases
• EEG gradually remit to normal state

21. 4 yr old child p/w progressive aphasia with partial motor seizure
LKS- spike and wave discharges at centro parietal or posterior temporal
areas which enhanced in sleep

22. LANDAU KLEFFNER SYNDROME
• Inter-ictal EEG-
• Background activity remains normal in most cases.
• High amplitude ,Epileptiform discharges are seen in Temporal -
Parietal areas/ Centro Parietal areas ( spikes, sharp waves /spike
and sharp wave)
• EEG abnormality is enhanced by sleep deprivation and in sleep.
• Ictal EEG –
• Focal Ictal pattern from Temporo-Parietal / Posterior Temporal
areas.

23. LANDAU KLEFFNER SYNDROME
• Onset between 2 and 8 yrs of life.(peak 5-7yrs)
• Sub acute onset of acquired verbal auditory agnosia with
normal previous cognition and development.
• Seizures ( Mostly Nocturnal and partial motor ) occur in 2/3rd
of patients.
• Behavioral and Cognitive disturbances are commonly
observed.
• Favorable prognosis

25. 7 year old child p/w right sided progressive hemiparesis with
simple partial seizure
Rasmussens encephalitis- Background activity shows slow theta waves
and epileptiform discharges in the left hemisphere

26. RASSMUSSENS ENCEPHALITIS
• Age of onset - 6-8 years (range: 2-13 years).
• Progressive unilateral hemispheric atrophy
• Focal intractable seizure (simple partial motor and epilepsia
partialis continua)
• Progressive neurological deficit
• EEG: background theta-delta activity with multiple independent
spike/sharp wave discharges in affected hemisphere.
• Enhanced by sleep deprivation as well in sleep.

27. DIAGNOSTIC ALGORITHM

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