There are two types of stimulator devices for epilepsy. In both types, the devices send electrical signals to the brain to prevent the electrical bursts that cause seizures.
The vagus nerve stimulator (VNS) is implanted under the skin, near your collarbone. A wire (lead) under the skin connects the device to electrodes attached to the vagal nerve that goes to your brain. The doctor programs the device to produce weak electrical signals that travel to your brain at regular intervals to prevent seizures.
The responsive neurostimulator (RNS) is implanted in the skull, and lead wires connect the device to the area of the brain that is causing the seizures. The doctor programs the device to notice abnormal electrical activity in the brain and send electrical signals to that area of the brain.
What To Expect
The nerve stimulator can start working right after the surgery. You may notice a slight bulge in the area where the device is. And the surgery will leave small scars where the wire leads were placed and where the device was implanted.
Why It Is Done
Nerve stimulation can be used in some people who have generalized or partial seizures, who have not responded well to antiepileptic medicines, and who are not candidates for epilepsy surgery.
Nerve stimulation is used in combination with other treatment. Nerve stimulation 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
Vagus nerve stimulation reduces the frequency of seizures that don't respond well to medicine and may make them less severe. About 2 out of 4 people say they notice that they have fewer seizures after surgery. But about 1 out of 4 people say they do not notice any benefit after surgery.footnote 1
The benefits of VNS seem to increase over time.
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.footnote 1
The responsive neurostimulator (RNS) is an option for some people whose seizures do not respond to other treatments. RNS reduces the frequency of seizures by about half, and the benefits seem to increase over time.footnote 2
Nerve stimulation is considered safe.
Side effects of the vagus nerve stimulator occur in some people when the device stimulates the nerve. They include:
- Throat pain.
- Hoarseness or slight voice changes.
- Shortness of breath.
Other possible risks of both types of nerve stimulators include:
- Numbness or tingling.
- Pain where the stimulator device is placed under the skin.
What To Think About
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.
- Englot DJ, et al. (2011). Vagus nerve stimulation for epilepsy: A meta-analysis of efficacy and predictors of response. Journal of Neurosurgery, 115(6): 1248–1255.
- Thomas GP, Jobst BC (2015). Critical review of the responsive neurostimulator system for epilepsy. Medical Devices: Evidence and Research, 2015(8): 405–411. DOI: 10.2147/MDER.S62853. Accessed May 19, 2016.
Current as of: November 19, 2019