Department: Ask the Expert
Spencer, David M.D.
David Spencer, M.D., is assistant professor of neurology at Oregon Health & Science University in Portland, Ore.
Q I have heard about the Vagus Nerve Stimulator. How do I know if this would be right for treating my epilepsy?
DR. DAVID SPENCER ADVISES:
A The Vagus Nerve Stimulator (VNS) works like a pacemaker for the brain.
No one knows exactly how the device works. But it is thought that the regular electrical impulses from the device short-circuit seizures before they spread across the brain.
A small device is implanted under the skin of the upper chest, and a wire — also placed under the skin — connects the unit to an electrode attached to the vagus nerve in the neck.
The procedure to implant the VNS is often an outpatient surgery, not requiring an overnight hospital stay.
Once the VNS is implanted, your doctor can turn it on and adjust it by touching a small plastic “wand” at the skin over the device. The wand is connected to a laptop or handheld computer that programs the VNS to send electrical impulses to the vagus nerve for short periods of time at regular intervals (for example, stimulation for 30 seconds every five minutes).
You can also activate the VNS yourself with a simple magnet once a seizure starts or if you sense that one is about to start. Studies have shown that this may abort or at least shorten a seizure.
Currently, the VNS is approved for use in patients whose seizures are not completely controlled by antiepileptic drugs. You shouldn't expect the VNS to be a panacea. There are only very rare instances in which the device has made someone seizure-free. At best, it will help reduce the number of seizures and the need for high doses of antiseizure drugs, but that it will not replace medications completely.