Vagus nerve stimulation: effectiveness and tolerability in 64 paediatric patients with refractory epilepsies

Aim. We discuss the effectiveness, tolerability, and safety of vagus nerve stimulation (VNS) as adjunctive therapy in 64 paediatric patients with refractory epilepsies. Materials and methods. Sixty-four patients (34 male and 30 female) implanted with VNS for refractory epilepsy were analysed. Electroclinical features were compatible with Lennox-Gastaut syndrome in 46 patients, focal epilepsies in 10 patients, Dravet syndrome in three patients, epilepsy with myoclonic-astatic seizures in three patients, and West syndrome in two. The NeuroCybernetic Prosthesis (NCP) system (Cyberonics, Webster, TX, USA) was employed and the following stimulation parameters were used: output current of 1 to 2.5mA, signal frequency of 30Hz, signal pulse width of 500 mu s, and signal "on" and "off" times of 30 seconds and 5 minutes, respectively. Results. Of 46 patients with LGS, 30 cases showed a significant improvement in seizure control, with a reduction in seizure frequency of at least 50%. Ten patients with focal epilepsy, three patients with myoclonic-astatic seizures, two patients with Dravet, and two patients with West showed a significant improvement in seizure control, with a reduction in seizure frequency of at least 50%. A good clinical response was evident early and efficacy progressively improved with the duration of treatment up to 36 months. In a significant number of patients, reduced seizure severity and shorter recovery time and hospital stay were also observed. VNS was well tolerated in all patients. Conclusion. VNS is an effective and well-tolerated treatment for paediatric patients with refractory epilepsies, improving quality of life and neuropsychological performance.