Vagus nerve stimulation for refractory epilepsy in children: More to VNS than seizure frequency reduction
Vagus nerve stimulation (VNS) is used increasingly as adjunctive therapy for refractory epilepsy. Studies of VNS in children report mainly seizure frequency reduction as a measure of efficacy and clinical details are often scanty. We report our experience with VNS in children with refractory epilepsy and emphasize the positive effects of VNS in terms of seizure severity. We reviewed 26 consecutive children who had VNS with a minimum follow-up period of 18 months. We examined their clinical characteristics, seizure types, seizure frequency, epilepsy syndrome diagnosis, and response to VNS in terms of seizure frequency and seizure severity. Fifty-four percent of patients responded to VNS with >or=50% seizure frequency reduction. Patients with Lennox-Gastaut syndrome (LGS) and tonic seizures had a higher responder rate; 78% (seven of nine patients) (p < 0.01). Status epilepticus (SE) episodes were reduced or ceased in the four patients with recurrent SE. Seizure severity, duration, and recovery time decreased in all responders. Increased alertness was reported in all responders and three nonresponders. Decreased seizure severity, recovery time, abolition of daytime drop attacks, and reduced hospitalization due to SE improved patients' lives over and above the benefit from seizure frequency reduction.