Vagus Nerve Stimulator (VNS)
The vagus nerve stimulator (VNS) may be useful for people with intractable epilepsy who are not good candidates for resective epilepsy surgery.
The VNS is a device similar to a cardiac pacemaker. Wires extend from the stimulator (which is usually implanted in the chest) and wrap around the left vagus nerve in the neck. The stimulator intermittently delivers a mild electrical current which may interrupt seizures. Patients may experience a reduction in the severity and frequency of their seizures, however, vagal nerve stimulation never results in a cure, and almost never produces complete seizure control. Approximately half the patients who have the VNS experience at least a 50 percent reduction in seizure frequency that persists for one year or longer.
People who experience a warning before their seizures can place a magnetic device over the stimulator to activate it. Activation of the stimulator at that time may help stop or shorten the length of the seizure. The VNS can be adjusted externally by a physician.
Because VNS rarely stops seizures completely, it is important that all treatment options be considered before VNS implantation. Resective epilepsy surgery or treatment with the newer antiepileptic medications may be more appropriate and cost-effective than the VNS in many situations. To be sure the diagnosis warrants treatment with the VNS, consult a comprehensive epilepsy center for a complete evaluation first.