Lennox Gastaut Syndrome

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  • Severe seizures in childhood
  • Presentation before eight years of age, most commonly between three and five years of age
  • Many cases evolve into Lennox Gastaut from other epilepsy syndromes, particularly West Syndrome (Infantile Spasm)


  • Mixture of seizure types
    • Tonic
    • Tonic-clonic
    • Atonic (drop attacks)
    • Myoclonic
    • atypical absences
  • Brief tonic seizures of seconds to 1 minute.
  • The seizures can cause falls.
  • Eyelid retraction, staring, mydriasis, and apnea are commonly associated
  • The seizures are frequent
  • Mental retardation before seizure onset in 20-60%


  • Spike slow wave complex superimposed on an abnormal, slow background.
  • The Spike slow wave complex and Sharp wave slow wave complex are generalized at a frequency of 1.5 to 2.5 Hz (slow), usually with the highest amplitude frontal.
  • Transient and shifting asymmetries are frequent
  • Non-REM sleep increases the discharges. In REM sleep the discharges decreases.
  • Hyperventilation or photic stimulation does not trigger the discharges.

Ictal EEG

  • Tonic seizure: typically fast rhythmic discarges of 10 – 20 Hz, increasing in amplitude.
  • Myoclonic seizures: bursts of arrhythmic, multiple spike-wave or irregular spike-wave activity
  • Atypical absence seizures: Slow (<2.5 Hz) and often asymmetric and irregular spike-and-wave activity


  • No drug is highly effective
  • Valproic acid, lamotrigine, topiramate, rufinamide, felbamate, and clobazam can be effective
  • Carbamazepine can worsen the drop attacks

Lennox gastaut in a 3 years and 10 months old boy (source) with multiple spike and slow waves and a slow basic rhythm

Lennox gastaut in a 3 years and 10 months old boy (source) EEGpedia.png