Abstracts

RATIONALE: While the anticonvulsant effect of intermittent vagal nerve stimulation generally increases over time, a subset of children respond relatively rapidly. At the end of this activity participants should be able to discuss factors which predict early success in the use of vagal nerve stimulation in children.
METHODS: Ninety two children (45 male; 47 female; average age at surgery 10.2[plusminus]4.6 years; range 2-20 years) were followed for at least 24 months following vagus nerve stimulator (VNS) implantation. Ten children had Lennox-Gastaut syndrome, 33 had cryptogenic seizures, 48 had symptomatic seizures, and 1 had primary generalized seizures. VNS stimulation parameters were adjusted according a standardized protocol. Seizure counts, as reported by the family, were recorded before surgery and at each follow-up visit. Patients were considered early responders if they had a sustained decrease in their seizure frequency of at least 75% by the 3 month visit.
RESULTS: The overall decrease in seizure frequency was 68[plusminus]30% at 12 months and 76[plusminus]29% at 18 months. Forty six patients (50%) were classified as early responders. These patients were more likely to have a normal MRI (52% vs. 33%), were more likely to have a cryptogenic form of epilepsy (41% vs 30%), and were less likely to have a symptomatic form of epilepsy (46% vs 57%). There was no difference between the groups with respect to gender, age of onset of epilepsy, duration of epilepsy, or number of anticonvulsants used prior to VNS implantation.
CONCLUSIONS: VNS is an efficacious anticonvulsant strategy for children, including young children, with a variety of types of epilepsy. Its efficacy is at least equal to that of currently available medications. Children with cryptogenic epilepsy with a normal MRI are more likely to respond rapidly to VNS therapy.
(Disclosure: Honoraria - Cyberonics, Inc.)