Abstracts

RATIONALE: Previous studies of long-term vagus nerve stimulation (VNS) for epilepsy allowed concurrent antiepileptic drug (AED) changes. We studied VNS used for 1 year as the sole new adjunct to unchanged AEDs . We specifically wondered whether VNS might have unique additive effects with any particular AED. From our work we hope neurologists gain insight into VNS use as sole new adjunctive antiepileptic therapy.
METHODS: A pilot exploration of the VNS registry was carried out to identify treated patients with 1 year of completed data and no changes in AEDs. We assessed seizure rates at baseline, and at 3 and 12 months follow-up. We compared patients on various baseline AEDs.
RESULTS: 668 patients were culled from the VNS registry. Median seizure rate reductions were 46% at 3 months and 57% at 12 months (p=0.126). Baseline AEDs were carbamazepine (n=273 patients), lamotrigine (238), valproate (201), topirimate (190) and phenytoin (151)(some patients were on multiple AEDs). Seizure rates did not differ according to baseline AEDs.
CONCLUSIONS: This is the first long-term study of a large patient population with VNS as the sole new adjunctive antiepileptic therapy without concomitant AED changes allowed. The seizure rate changes can be attributed to VNS. We did not see significant improvement between 3 and 12 months of therapy. No particular AED appears to have unique additive antiepileptic effects with VNS.
[Supported by: Cyberonics.]; (Disclosure: Grant - Dr. Labar has clinical research grants from Cyberonics., Consulting - Dr. Labar consults for Cyberonics., Honoraria - Dr. Labar is on the speakers bureau for Cyberoncs.)