Vagus nerve stimulation is a procedure that stimulates a person's vagus nerve with electrical impulses. Vagus nerve stimulation (VNS) may be used to treat epilepsy when other types of treatments have failed to work. VNS is also used to treat depression and it is being studied for conditions such as migraines, Multiple Sclerosis and Alzheimer's disease. There is one vagus nerve on each side of a person's body; they run from the brainstem through a person's neck to their chest and abdomen.
A technique used to treat epilepsy. It involves implanting a pacemaker-like device that generates pulses of electricity to stimulate the vagus nerve. In 1997, the United States Food and Drug Administration (FDA) approved the use of VNS as an adjunctive therapy for partial-onset epilepsy. In 2005, the FDA approved the use of VNS for treatment-resistant depression. Although the use of VNS for refractory depression has been endorsed by the American Psychiatric Association, the FDA's approval of VNS for refractory depression remains controversial.
With VNS, a device is surgically implanted underneath the skin on a person's chest. A wire is threaded under the skin connecting the device to the left vagus nerve. When it is activated, the device sends electrical signals along the vagus nerve to the person's brainstem, which sends signals to certain areas of the brain.
The Reasons for VNS Use
A number of people with epilepsy do not respond well to anti-seizure medication. VNS might be an option to reduce the frequency of seizures in those who have not been helped by medication use. VNS may also be helpful for people who have not responded to standard treatment for depression such as psychological counseling or anti-depressant medication. A VNS might be a good choice for people if the person:
Many people with epilepsy don't respond to anti-seizure drugs. Vagus nerve stimulation may be an option to reduce the frequency of seizures in people who haven't been helped by medications.
Risks Associated with VNS
For the majority of people, VNS is safe. Yet it does have some risks associated with using it, not only from the surgery to implant the device, but from brain stimulation as well. Surgical complications with VNS are rare and similar to risks associated with other types of surgery. These risk include the following:
There are some different side-effects and health issues associated with VNS. The list involves some effects and issues that may be troubling for some. These side-effects may include:
For the majority of people, side-effects are something they find to be tolerable. The side-effects might decrease over time, but some side-effects may be troubling for as long as a person uses VNS. Adjusting the electrical impulses can help to minimize the effects. If side-effects are something the person is unable to tolerate, the device can be shut of either temporarily or permanently.
Preparing for a VNS Procedure
It is important for a person to consider very carefully the pro's and con's of VNS prior to making the decision to pursue the procedure. Make sure you know what all of your other treatment options are as well as ensuring that both you and your doctor feel that VNS is the best option. Ask your doctor precisely what you should expect during surgery and after the pulse generator is placed.
Prior to the surgery, your doctor will perform a physical examination. You might need blood or other tests to make sure you do not have any health concerns that may present an issue. Your doctor will have you begin taking antibiotics before the surgery in order to prevent infection. You might need to stop taking some medications ahead of time and your doctor may ask you not to eat anything the night before the surgery. When you set up your appointment for surgery, make sure you are clear on precisely what steps you need to take.
VNS and the Surgery
Surgery to implant the VNS device is performed either on an outpatient basis, something that permits you to return home the same day, or on an outpatient basis, which requires you to spend the night in the hospital. The surgery itself may take 1-2 hours. You might remain awake but have medication to numb the surgery area, or you might be unconscious during the surgery.
The surgery itself doesn't involve your brain. Two incisions are made, one on your chest and the other on the left side of the neck. The pulse generator is implanted in the upper left side of your chest. The device is meant to be a permanent implant, but it can be removed if necessary. The pulse generator is around the same size as a stopwatch and runs on battery power. A lead wire is connected to the pulse generator and is guided underneath your skin from your chest up to your neck. The lead wire is then attached to your vagus nerve.
Following the Implant Procedure
The pulse generator is turned on during a visit with your doctor a few weeks following the surgery. It can then be programmed to deliver electrical impulses to your vagus nerve at different frequencies, durations and currents. Vagus nerve stimulation (VNS) commonly begins at a low level and is increased gradually depending on your symptoms and any side-effects you experience.
VNS is programmed to turn on and off in specific cycles. You might have some tingling sensations, or slight pain in your neck when the nerve stimulation is on. The stimulator does not detect seizure activity or symptoms of depression. When it is turned on, the stimulator turns on and off at the intervals your doctor determines to be appropriate. The health care worker with epilepsy I met at the Veterans Administration swears by his VNS device and showed me how he uses a magnet to activate it.
People with an implanted VNS device are provided with a hand-held magnetic device so they may control the stimulation of their vagus nerve. The magnetic device enables you to temporarily turn off stimulation, which might be necessary when you pursue certain activities such as singing, public speaking, exercising, or when you are eating if you experience issues with swallowing. It also allows you to turn it on if you experience auras or other warning signs of a seizure.
You have to visit your doctor on occasion to make sure the pulse generator is working as it should be and that it has not shifted out of position. For safety reasons, magnetic resonance imaging (MRI) scans are usually limited if you have a VNS stimulator implanted. Generally, MRI's of your head may be performed if the right kind of MRI machine is used. MRI scans of a person's spine and body cannot be performed when a person has a VNS device.
The Results of VNS Device Implantation
VNS is not a cure for epilepsy. Most people with epilepsy will not stop experiencing seizures completely. Yet many people with epilepsy will have fewer seizures, as many as 30-50% fewer. The intensity of your seizures might decrease as well.
It may take as long as two years of VNS before you notice any significant reduction in the number of seizures you experience. VNS might also shorten your recovery time following a seizure. People who have had VNS to treat epilepsy usually have an improved quality of life.
The results of studies remain mixed on whether or not VNS is an effective treatment for depression. It may take a number of months of treatment before you notice any improvements in the symptoms of depression you experience. VNS also does not work for everyone and usually is not meant to replace traditional treatments. Health insurance companies may or may not pay for what is an expensive procedure. All of the studies done related to other health conditions and VNS such as Alzheimer's disease, Multiple Sclerosis and migraines have been too small to make any conclusions about how well VNS may work for them; additional research is needed.
Vagus Nerve Stimulation (VNS)
Vagus Nerve Stimulation (VNS)
Vagus nerve stimulation