Ictal ontogeny in Dravet syndrome.

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

METHODS: 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).

RESULTS: 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%).

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

SIGNIFICANCE: 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.