DEVELOPMENTAL AND/OR EPILEPTIC ENCEPHALOPATHY WITH SPIKE-WAVE ACTIVATION IN SLEEP (DEE-SWAS, EE-SWAS)

• Lennox-Gastaut syndrome - slow spike-waves are frequent both in awake and asleep states, the sleep EEG shows generalized paroxysmal fast (≥10Hz) activity and tonic seizures may be captured, focal motor seizures are uncommon.
• Structural brain abnormality - spike-wave activation in sleep can occur without associated cognitive or behavioural regression.
• Self-limited focal epilepsy syndromes of childhood - spike-wave activation in sleep can occur without associated cognitive or behavioural regression.
• Etiologies with regression (e.g. autism spectrum disorder) - spike-wave activation in sleep can occur, but regression is not temporally associated with the emergence of the spike-wave activation in sleep.

CAUTION This syndrome is rare, accounting for only ~0.5% of all epilepsy presentations, it should not be over-diagnosed, there should be clear and persisting regression temporally related to the emergence of spike-wave activation in non-REM sleep.