What is Vagus Nerve Stimulation (VNS)
Vagus nerve stimulation is clinically used since 1997 in children and adults with epilepsy, particularly (but not only) complex partial epilepsy that remains incapacitating despite maximal antiepileptic medication.Epilepsy prevalence is estimated at 1% worldwide.
About 5% to 30% of people with epilepsy have medically refractory seizures. Since 1997 over 45.000 such units have been (re)implanted worldwide.
A battery powered pulse generator is implanted under the skin of the upper left chest. A wire is tunneled under the skin and connected to the left vagus nerve in the neck. Stimulation parameters are stored in the pulse generator via a PC or PDA. Patients or carers may then switch the stimulator on and off for a predetermined period of time by passing a controller over the generator. Alternatively, using the same controller, patients may set the stimulator to high stimulation for a predetermined period of time (at the onset of a seizure/aura for example). The implanted stimulator is rechargeable and requires recharging only once a week (for 2 hrs). This is done with a convenient charger, at home. As the lifetime ofthe device is extended up to 15 years, the last 5 years of its life will require somewhat more frequent recharging or longer recharge sessions