Ictal ontogeny in Dravet syndrome

To define seizure characteristics of Dravet syndrome (DS) with video-electroencephalographic (EEG) recording in different age groups.

We reviewed 23 patients with 63 seizures in different age groups: group 1 (0-5years old); group 2 (6-10years old); and group 3 (11 or above).

We included 7, 11 and 5 patients in groups 1, 2, and 3 respectively. Younger children had seizures while awake (p=0.005), provoked seizures (p=0.05), focal seizure semiology (p=0.02) and long seizure duration (p=0.0004). Older children had seizures from sleep (p=0.004), generalized seizure semiology (p=0.01) and short seizure duration (p=0.0007). A generalized ictal discharge was the most commonly observed EEG pattern (15/23, 65%), more frequently found in older children (p=0.01). Ten patients (43%) had unclassified seizures or seizures with discordant EEG results. Postictal EEG suppression was found in 9 (39%).

The phenotype of seizures and ictal EEG patterns in DS vary with age.

These findings will enhance the recognition of DS in the adolescent population. The incidence of postictal EEG suppression seen in DS is significant because it is a possible biomarker for sudden unexpected death in epilepsy.