Efficacy of vagus nerve stimulation for epilepsy by patient age, epilepsy duration, and seizure type.

Medically refractory epilepsy is a morbid condition, and many patients are poor candidates for surgical resection because of multifocal seizure origin or eloquence near epileptic foci. Vagus nerve stimulation (VNS) was approved in 1997 by the US Food and Drug Administration as an adjunctive treatment of intractable epilepsy for individuals aged 12 years and more with partial epilepsy. Controversy persists regarding the efficacy of VNS for epilepsy and about which patient populations respond best to therapy. In this article, the authors retrospectively studied a patient outcome registry and report the largest, to their knowledge, analysis of VNS outcomes in epilepsy.