Long-term seizure reduction with vagus nerve stimulation in Dravet syndrome

To assess the long-term efficacy of vagus nerve stimulation (VNS) in Dravet syndrome and identify key factors influencing treatment response.

We conducted a two-center, retrospective cohort study of 15 patients (six females, nine males; median age at seizure onset 4 months [range 2-12 months]) with Dravet syndrome who underwent VNS implantation. Seizure frequency was evaluated over 12 months and up to 10 years after implantation. Linear mixed-effects regression was used to analyze the impact of antiseizure medications (ASMs) and VNS parameters on seizure outcomes.

A 50% or greater reduction in seizure frequency was observed in 93.3% (14 of 15) of patients at 12 months and 86.7% (13 of 15) of patients across the 10-year follow-up. This seizure reduction was independent of ASM use; the VNS duty cycle was a significant predictor of seizure reduction. Two individuals (13.3%) experienced minor adverse events.

VNS provides durable seizure reduction in Dravet syndrome, independent of ASM adjustments. These findings highlight the importance of early VNS initiation and parameter optimization in managing genetically defined epilepsy syndromes.