Vagus nerve stimulation therapy for intractable epilepsy: Current status

Abstract

Vagus nerve stimulation (VNS) is an efficient and well-tolerated adjunct therapy for drug-resistant epilepsy. The system is comprised of an implantable, programmable pulse generator and a helical bipolar electrode, which continuously delivers an intermittent current to the midcervical portion of the left vagus nerve. Although the mechanisms of action are still under discussion, VNS likely exerts its effect by attenuating excitatory activity while augmenting inhibitory activity in wide cortical areas. VNS has been approved for the treatment of intractable epilepsy all over the world. Because Japan essentially remains the single country where VNS is not approved for clinical use, there are major barriers to providing this treatment to patients with drug-resistant epilepsy in whom resective surgery is not indicated or who did not achieve satisfactory seizure control. The author advocates that proposals for the approval of VNS be considered by the associated academic societies.