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 approximately 2 hours to surgically implant the VNS device in the chest.

What To Expect After Treatment

The vagus nerve stimulator can begin 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 has been approved for use in treating people over age 12 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. While it does not eliminate the need for medicine, 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.

It appears from initial research that the benefits of VNS increase over time. In medical studies, about 3 out of 10 people had better control of their seizures after 3 months. After 12 months of VNS, about 4 out of 10 people had fewer seizures. After 18 months, about 3 out of 10 people had one-half the seizures that they had before, and 2 out of 10 people had only one-fourth the seizures they had before. ¹

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.

Although the device has not yet been approved for use in children, initial studies show that it may be as effective in children as in adults. VNS also improved independence, mood, and learning in some children. ²

Risks

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.

Doctors are not exactly sure how or why the vagus nerve stimulator prevents seizures, and its long-term effects, if any, have not been studied.

Vagus nerve stimulation has not yet been approved for use in children under age 12, but early studies suggest that it may significantly benefit children with difficult-to-treat forms of epilepsy.

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Citations

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.