An unexpected EEG course in Dravet syndrome.

A puzzling EEG pattern combining frontal slow bi-tri spikes followed or not by slow waves when awake and activated by sleep with 5-10s discharges of 8-9Hz spikes in a minority of adolescents with Dravet syndrome (DS) was recorded in the context of stable seizure and cognitive status, and unchanged antiepileptic medication. Tonic seizures were frequently reported in patients with this EEG pattern (3/5). This EEG pattern could suggest that of Lennox-Gastaut syndrome (LGS) but it exhibits clear differences and therefore should not be considered as a change into LGS but as a previously overlooked unusual pattern in the adolescent course of DS.