Abstracts

Rationale: We sought to determine the long-term efficacy and safety of vagus nerve stimulation (VNS) treatment in children with the Lennox-Gastaut syndrome (LGS). Methods: We prospectively followed nine VNS-treated LGS children for 1 year. We compared the 4 weeks historical baseline seizure rates, with the median seizure rates for the entire 12 months of VNS. We also compared the number of antiepileptic drugs (AEDs) at baseline versus 12 months of follow-up. We also studied the efficacy of magnet use in terminating seizures. Statistics used were the Wilcoxon matched pairs test and Pearson bivariate correlation test. Results: Mean age of the population was ten years (range 4-16). All patients had multiple seizure types and slow spike and wave discharges on EEGs. Median seizure rate reduction on VNS was -41% (p= 0.02). Three out of nine children had greater than 90% reduction, one had greater than 75% reduction. Three had greater than 50% reduction and two did not respond. Mean AEDs used at the time of implant was 4.0 (range 3-7). Mean number of AEDs after 12 months of VNS therapy was 2.5 (range 1-5). Four out of nine patients reduced the number of AEDs by two or more after twelve months of VNS. Three patients reported decreased seizure duration with on-demand magnet activation of VNS. No serious adverse events occurred and no patient discontinued treatment. Conclusion: The antiepileptic efficacy of VNS in children with LGS was maintained during the first year of treatment. The efficacy of magnet activation in terminating seizures needs to be evaluated further.