The place of vagus nerve stimulation in the treatment of epilepsy

Cervical vagus nerve stimulation (VNS) with an implanted neuro-cybernetic p rosthesis reduces the number of refractory seizures, especially in patients with par tial epilepsy and with lennox-Gastaut syndrome by 50% in up to ap proximately 40% of cases. Within three months following implantation, the n umber of seizures drops by about 25% and in some patients complete seizure control may be seen. In individual cases, antiepileptic effects may emerge as late as six months. Patients can individualize stimulation with a magnet . Good tolerability is an advantage of VNS and the implantation is generally well tolerated. During stimulation hoarseness may occur and is more often a t higher stimulus strength. Dyspnea has been noted in patients during exert ion and in those with obstructive pulmonary disease. Preexisting dysphagia may increase the risk of aspiration during stimulation. Interactions with o ther drugs including anticonvulsants have not been noted. Predicting the response in the individual patient is as difficult as in dru g treatment. After 3-5 years the battery needs to tie replaced depending on the stimulus strength used. Prior to implantation care should be taken to determine that the seizures cannot be treated by adequate standard drug the rapy and, in addition, a surgically amenable epilepsy syndrome should have been ruled out. Prior vagotomy is df course an exclusion criterion. In summ ary, VNS is recommended in children, adolescents and adults with severe sei zures that cannot be treated successfully with either anticonvulsants or re sective epilepsy surgery. VNS may be successful in failures of epilepsy sur gery.