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
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
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
- Hoarseness or slight voice changes.
- Shortness of
In children, vagus nerve stimulation may cause increased
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.
Schachter SC (2002). Vagus nerve stimulation therapy
summary: Five years after FDA approval. Neurology, 59(6,
Suppl 4): S15–S20.
Buchhalter JR, Jarrar RG (2003). Therapeutics in
pediatric epilepsy, part 2: Epilepsy surgery and vagus nerve stimulation.
Mayo Clinic Proceedings, 78(3): 371–378.
|Primary Medical Reviewer||Susan C. Kim, MD - Pediatrics|
|Specialist Medical Reviewer||Steven C. Schachter, MD - Neurology|
|Last Revised||August 26, 2011|