Epileptic encephalopathy -EEG


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EEG in epileptic encephalopathy

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Epileptic encephalopathy -EEG

  2. 2.  Severe brain disorders in which the epileptic electrical discharges may contribute to progressive psychomotor dysfunction.  Early age of presentation.  EEG paroxysmal activity.  Multi-form,intractable and often aggressive seizures.  Severe cognitive, behavioural and neurological deficits.  Poor prognosis with occ. early death.
  3. 3.  Neonates.  Early myoclonic encephalopathy.  Ohtahara syndrome.  Infancy.  West syndrome.  Dravet syndrome.  Childhood.  Myoclonic astatic epilepsy.  Epileptic encephalopathy with CSWS including Landau- Kleffner syndrome.  Lennox – Gastaut syndrome.  Rasmussen syndrome.
  4. 4. Evolution of epileptic encepaphalopathies
  5. 5. Early Myoclonic Encephalopathy  Onset < age 3 m, initially fragmentary myoclonus and then erratic focal seizures, massive myoclonias or tonic spasms.  EEG - suppression–burst activity, which evolves into hypsarrhythmia,accentuated during sleep,persists for prolonged periods.  Inborn errors of metabolism mc causes.  >50% die within weeks or months.
  6. 6. The inter-ictal EEG of early myoclonic encephalopathy is a repetitive suppression–burst pattern without physiological rhythms
  7. 7. Ohtahara Syndrome (early infantile epileptic encephalopathy with suppression–burst).  10 days to 3 months of age (occ. Intrauterine).  Tonic spasms - forward tonic flexion lasting 1–10 s that is singular or in long clusters 10–300 times every 24 h.  1/3rd - erratic focal motor clonic seizures.  Alternating hemiconvulsions or GTCS are exceptional.  Myoclonic seizures are rare.  ILAE Definition  Very early onset, within the first few months of life, frequent tonic spasms and a suppression–burst EEG pattern in both the waking and sleeping states.
  8. 8.  The EEG - Bursts last for 2–6 s with intermixed suppression period which lasts for 3–5 s.  Tonic spasms -ictal EEG.  Diffuse desynchronisation with disappearance of suppression–burst activity when tonic spasms cluster in intervals of 5–10 s.  A pattern in which the suppression–burst pattern becomes more frequent, more diffuse and of higher amplitude compared to the inter-ictal pattern.  Progression of Clinical and Electroencephalogram Features to West Syndrome and LGS.  Gradual disappearance of the BSP and the emergence of hypsarrhythmia within 3–6 mths from onset which progress later to the slow spike-wave EEG patterns of LGS.
  9. 9. Ohtahara syndrome: suppression – burst pattern
  10. 10. West syndrome (Epileptic spasms).  Triad of infantile spasms, arrest of psychomotor development, and hypsarrhythmia.  Onset peaks between the ages of 4 and 7 months.  Clusters of sudden, brief (0.2–2 s), bilateral tonic contractions of the axial and limb muscles.  1–30% may have lateralising features.  Precipitating factors- twilight state,sudden loud noises or tactile stimulation,feeding.  Gibbs and Gibbs –hypsarrhythmic interictal EEG.  Lissencephaly and Aicardi syndrome -frequent suppression–burst activity.  West syndrome of TS- spike foci with SBS in sleep are frequent.
  11. 11. EEG of a 6-month-old infant with developmental delay and infantile spasms, showing typical hypsarrhythmic pattern.
  12. 12. Ictal EEG  Variable lasting for 0.5 s to 2 min.  Brief attacks (1–5s) consisting of:  a high-voltage, generalised slow wave.  episodic, low-amplitude fast activity.  marked diffuse attenuation of EEG electrical activity (electrodecremental ictal EEG pattern).  Prognosis  Mortality - 5%.  60% - develop other seizure types  50%-permanent motor disabilities  2/3rd -severe cognitive and psychological impairment.  5–12% - normal mental and motor development.
  13. 13. Infantile spasm noted in second 7 with an electrodecremental response obtained in a 3-yr-old child with TS.
  14. 14. Dravet Syndrome (Severe Myoclonic Epilepsy in Infancy)  Onset is always <1yr of life, with a peak age of 5 m.  Tetrad of seizures  Early onset infantile febrile clonic convulsions  Myoclonic jerks  Atypical absences  Complex focal seizures.  Precipitating Factors  Febrile illnesses , warm environment (hot baths), Photic and pattern stimulation, movements and eye-closure.
  15. 15.  Inter-Ictal EEG  Initial -20% show normal BG with photoparoxysmal discharges of spikes/ polyspikes-slow waves.  Within 1 year, EEG - abnormal slow BG with frequent asymmetrical paroxysms of polyspikes or spikes-slow waves.  Ictal EEG  Varies according to seizure type.
  16. 16. Lennox–Gastaut Syndrome  Starts between 1 and 7 yrs with a peak at 3–5 years.  10–30% of cases develop from West syndrome or other epileptic encephalopathies.  Triad of  Polymorphic intractable seizure that are mainly tonic (80%), atonic (50%)and atypical absence seizures (70%), Myoclonic Jerks(11–28%).  Cognitive and behavioural abnormalities.  EEG with paroxysms of fast activity and slow (less than 2.5 Hz) generalised spike-wave discharges (GSWD).
  17. 17. Tonic seizure started clinically with a scream (vertical arrow) and episodic nystagmus (oblique arrows shows EM artefacts). The ictal EEG consisted of an abrupt onset of flattening, which lasted for 25 s, followed by high-amplitude generalised sharp and slow waves at approximately 1 Hz. The EEG returned to its pre- ictal state after approximately 1 min from the onset of the seizure.
  18. 18. EEG fast paroxysms are associated with inconspicuous manifestations of tonic seizures (slight tonic eyelid opening).
  19. 19. Ictal discharge contains features of tonic (episodic fast activity) and absence (slow spikes and waves) seizure.
  20. 20. Fast paroxysms contain rhythms > 10 Hz. MISD mainly occur in the transition from West to LGS. Very rapid (20 ± 5 Hz) and initially of low amplitude, progressively increasing to 50–100 mV.
  21. 21. EEG of a 16-yr-old child with MR and tonic seizures, showing slow spike wave activity superimposed on a slow BG.
  22. 22. EEG of an 11-yr-old pt with LGS showing GPFA.
  23. 23. Tonic seizure in a patient with LGS.
  24. 24. Landau–Kleffner Syndrome Acquired Epileptic Aphasia)  Partly reversible, epileptic encephalopathy of childhood manifesting with acquired verbal auditory agnosia and fluctuating course of the linguistic disturbances that occur together with other cognitive and neuropsychological behavioural abnormalities.  Age at onset : 2–8 yrs with a peak at 5–7 yrs.  Epileptic seizures and behavioural and psychomotor disturbances occur in 2/3rd of patients.
  25. 25. Inter-ictally, clusters of sharp-slow wave focal discharges maximum around the left Rolandic regions (left). They became continuous during natural sleep (right). Ictal discharge starts from the left central regions and rapidly spreads to the neighbouring regions. The first clinical signs consisted of right facial spasms (arrow; also note muscle artefacts on the right) progressing to hemi- convulsions.
  26. 26.  Prognosis  Seizures and EEG abnormalities usually remit by 15yrs of age.  50% of patients -relatively normal life with 10–20% achieving complete normalisation.  50% left with permanent sequelae that may be very severe.
  27. 27. ESES in a 9-year-old boy with Landau-Kleffner syndrome.
  28. 28. Epilepsy with Continuous Spike and Waves during Slow-Wave Sleep (Epileptic Encephalopathy with Electrical Status Epilepticus during Slow-Wave Sleep)  Partly reversible, age-related childhood epileptic encephalopathy characterised by the triad of:  EEG CSWS  Seizures(except tonic seizures).  Neuropsychological and motor impairment.  Onset of seizures - 2 m to12 yrs, with a peak at 4–5 yrs.
  29. 29. 3 stages of evolution.  I stage is before the discovery of CSWS  The EEG shows multi-focal spikes and bisynchronous generalised sharp or spike-wave discharges.  II stage is when CSWS is found  Increase in seizures and the appearance or deterioration of neuropsychological symptoms that prompt a sleep EEG.  Continuous bilateral and diffuse slow spikes-waves of 1.5–2 Hz during NREM sleep is the defining EEG pattern of ECSWS.  III stage is after clinical and EEG remission starts.
  30. 30. Encephalopathy with CSWS