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Vagus Nerve Stimulator for Epilepsy

Similar to a pacemaker, a vagus nerve stimulator (VNS) is a small device implanted under the skin near your collarbone. A wire (lead) under the skin connects the device to the vagus nerve in your neck. The doctor programs the device to produce weak electrical signals that travel along the vagus nerve to your brain at regular intervals. These signals help prevent the electrical bursts in the brain that cause seizures.

After it is implanted in your body, the battery-powered device can be programmed from outside your body by your doctor. You can also use a handheld magnet to turn the device on if you feel a seizure about to start. And turn it off if it is causing unpleasant side effects.

It takes about 2 hours to surgically implant the VNS device in the chest.

What To Expect After Treatment

The vagus nerve stimulator can start working right after the surgery (as soon as the doctor programs it). You may notice a slight bulge in the area under your collarbone where the device is. And the surgery will leave small scars on the side of your neck where the wire lead was placed and on your chest where the device was implanted.

Why It Is Done

Vagus nerve stimulation can be used in some people who have partial seizures, who have not responded well to antiepileptic medicines, and who are not candidates for epilepsy surgery.

VNS is used in combination with medicine or surgery. VNS does not eliminate the need for medicine, but it can help reduce the risk of complications from severe or repeated seizures.

How Well It Works

The vagus nerve stimulator reduces the frequency of partial seizures that don't respond well to medicine and may make them less severe. It is used along with antiepileptic medicines or epilepsy surgery to control partial seizures.

The benefits of VNS seem to increase over time. In one study:1

  • After 3 months, the number of seizures decreased by about one-third.
  • After 12 months, the number of seizures decreased by about half. And in 2 out of 10 people, the number of seizures decreased by about three-fourths.

For people who can sense when they are about to have a seizure, turning on the VNS using their hand-held magnet can sometimes prevent the seizure. It may also shorten a seizure already in progress.

Studies show that VNS may also be effective in children. VNS improved independence, mood, and learning in some children.2


The vagus nerve stimulator is considered safe. Mild side effects occur in some people when the device stimulates the nerve. The most common side effects include:

  • Coughing.
  • Throat pain.
  • Hoarseness or slight voice changes.
  • Shortness of breath.

In children, vagus nerve stimulation may cause increased hyperactivity.

What To Think About

Vagus nerve stimulation is not a cure for epilepsy, and it does not work for everyone. It does not replace the need for antiepileptic drugs. It is most likely to be available at an epilepsy center.

Complete the special treatment information form (PDF)(What is a PDF document?) to help you understand this treatment.


  1. Schachter SC (2002). Vagus nerve stimulation therapy summary: Five years after FDA approval. Neurology, 59(6, Suppl 4): S15–S20.

  2. Buchhalter JR, Jarrar RG (2003). Therapeutics in pediatric epilepsy, part 2: Epilepsy surgery and vagus nerve stimulation. Mayo Clinic Proceedings, 78(3): 371–378.

ByHealthwise Staff
Primary Medical ReviewerSusan C. Kim, MD - Pediatrics
Specialist Medical ReviewerSteven C. Schachter, MD - Neurology
Last RevisedAugust 26, 2011

WebMD Medical Reference from Healthwise

Last Updated: August 26, 2011
This information is not intended to replace the advice of a doctor. Healthwise disclaims any liability for the decisions you make based on this information.

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