Vagus Nerve Stimulation Therapy in Refractory Epilepsy: 18-Month Follow-up Multicenter Study

,

Abstract

PURPOSE: Vagus nerve stimulation (VNS) with the NeuroCybernetic Prosthesis (NCP) is a recently approved treatment for patients with medically intractable epilepsy in Korea, who are unsuitable candidates for conventional epilepsy surgery. This is the first report about the efficacy and safety of VNS in Korea.
METHODS
Fourteen patients (male 9 and female 5) recruited from 5 epilepsy centers were treated with VNS for 18 months : 13 suffered from partial epilepsy and 1 from Lennox-Gastaut syndrome. Mean age was 24 years (range : 7-45 years) and mean age at seizure onset 10.9 years (range : 0.5-41 years). All had medically intractable epilepsy and 4 patients had the previous history of epilepsy surgery. They were prospectively assessed at 3, 12, and 18 months after VNS with regard to seizure frequencies and side effects.
RESULTS
The number of patients achieved greater than 50% reduction of seizure frequency were 4, 6, and 6 (43%) at 3-, 12-, and 18-month follow-up respectively. Two patients who had showed initial improvement (at 3 month follow-up) returned to the baseline overtime. Four patients without initial improvement had more than 50% reduction of seizure frequency at 12-month follow-up. Side effects were usually mild and related to the period of stimulation : hoarseness, dysphonia, coughing, and local paresthesia. In 3 patients, the stimulators were turned off, due to the patient's refusal, severe dental pain, and dyspnea in each patient.
CONCLUSIONS
Our data suggest that vagus nerve stimulation is an effective and safe adjunctive treatment for patients with medically refractory epilepsy. One should pay attention to rare but potentially serious adverse effects including dyspnea.