Lennox-Gastaut syndrome in 10-year-old girl (EEG)

This 10-year-old girl with severe structural Lennox-Gastaut syndrome from age 6 months had a marked neuronal migration deficit in the right hemisphere, and her seizures were multiform and intractable to any medication. (A) A grossly abnormal interictal EEG with continuous, high-amplitude, sharp-slow-waves or spike-slow-waves. These were multifocal right or left, mainly frontal but also midline or posterior. (B) A tonic seizure started clinically with a scream (black arrow) and episodic nystagmus (red arrows show the eye movement artefacts of the nystagmus). The ictal EEG consisted of an abrupt onset of flattening, which lasted for 25 seconds, followed by high-amplitude, generalized, sharp and slow waves at approximately 1 Hz. The EEG returned to its preictal state after about 1 minute from the onset of the seizure. Despite unilateral structural abnormalities, the interictal, ictal, and postictal EEG abnormalities were not consistently lateralized. (Courtesy of C P Panayiotopoulos: Panayiotopoulos CP. A Clinical Guide to Epileptic Syndromes and Their Treatment. Revised 2nd ed. London: Springer, 2010.)