Abstracts

Rationale: The VNS was approved by the FDA in 1997 for treatment of complex partial seizures (CPS) in persons 12 years and older. Unfortunately, effect on specific seizure types other than CPS, and efficacy in special needs children has not been systematically assessed. This study analyzes the response of drop seizures (rather than total number of seizures), and includes changes of medications as an outcome confounder. Methods: VNS was implanted in 21 children (13 male) age 4-19 years with medically refractory severe drop seizures between 1998 and 2006. Follow-up ranges from 6 months-8 years 9 months. Seizure frequency and medications pre-implant and at latest follow-up are reported.Results: 17 of 21 patients had a dramatic decrease in drop seizures: 10 had zero drops at latest follow-up; 7 had 90% decrease. 4 had no change in drop seizures. 10 had at least 75% reduction in other seizure types. Only 3 patients were on the same medications at latest follow-up as pre-implant. 2 had a corpus callosotomy after implant of VNS. Conclusions: A dramatic reduction in drop seizures was seen in 75% of children in this series. VNS is effective in reducing drop seizures in children with severe medically refractory seizures. The benefit seen in these children reflects the effects of VNS therapy, medications, and in some cases corpus callosotomy.