Vagus nerve stimulation for depression

Definition

Vagus nerve stimulation is a procedure that sends electrical impulses into your brain in an effort to improve depression symptoms. Sometimes called vagal nerve stimulation, vagus nerve stimulation is one of a few newer brain-stimulation methods designed to treat chronic depression when other treatments haven't worked.

There's one vagus nerve on each side of your body. Each nerve runs from your brainstem through your neck and down to your chest and abdomen.

With vagus nerve stimulation, a device called a pulse generator is surgically implanted in your chest. A wire threaded under your skin connects the pulse generator to the left vagus nerve in your neck. The pulse generator sends out electrical signals along the vagus nerve to your brain. These signals affect mood centers of your brain, which may improve depression symptoms.

Why it's done

Antidepressant medications, psychological counseling (psychotherapy) or electroconvulsive therapy (ECT) can improve depression in most people. But everyone's different, and for some people these standard depression treatments don't work very well. In such cases, vagus nerve stimulation may be added to standard treatments to help relieve symptoms.

When vagus nerve stimulation may be a good option
The Food and Drug Administration (FDA) has approved vagus nerve stimulation for people who:

• Are adults (age 18 or older)
• Have chronic, hard-to-treat depression (treatment-resistant depression)
• Haven't improved after trying four or more medications or electroconvulsive therapy (ECT), or both
• Continue standard depression treatments along with vagus nerve stimulation

Vagus nerve stimulation doesn't always relieve depression
Vagus nerve stimulation has been used for treatment-resistant epilepsy for over a decade and is known to produce good results. The benefits for depression aren't so clear.

The possibility that vagus nerve stimulation might work to treat depression was identified when it was being studied in people with epilepsy. Researchers noticed that some people who were getting vagus nerve stimulation had an improved mood. This led to further studies, which have produced mixed results.

For most people, vagus nerve stimulation doesn't significantly ease depression symptoms. However, it does seem to make a significant difference for some people. However, results vary from person to person.

Some mental health experts don't recommend its use for depression at all, and most health insurance companies don't cover the procedure for depression treatment. This can be a concern, as the vagus nerve stimulation device and surgery to implant it is expensive.

Vagus nerve stimulation

Vagus nerve stimulation

In vagus nerve stimulation, an implanted pulse generator and lead wire stimulate parts of your brain to stabilize the abnormal electrical activity.

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Risks

For most people, vagus nerve stimulation is safe. But it does have some risks, both from the surgery to implant the device and from the brain stimulation.

Surgery risks
Surgical complications with vagus nerve stimulation are rare and are similar to the dangers of having other types of surgery. They include:

• Pain where the cut (incision) is made to implant the device
• Infection
• Damage to the vagus nerve
• Breathing problems
• Nausea
• Heart problems
• Incision scarring
• Vocal cord paralysis, which is usually temporary — in some people it has been caused by fiddling with the transmitter under the skin after implantation

Side effects after surgery
Some of the side effects and health problems associated with vagus nerve stimulation can include:

• Voice changes (this occurs in over half the people who have the procedure)
• Hoarseness
• Throat pain
• Cough
• Tingling
• Neck pain
• Chest pain or spasms
• Breathing problems, especially during exercise
• Difficulty swallowing
• Tingling or prickling of the skin

For most people, side effects are tolerable. They may improve over time, but some side effects may be bothersome for as long as you use vagus nerve stimulation. Adjusting the electrical impulses can help minimize these effects. If side effects are intolerable, the device can be shut off temporarily or permanently.

Other complications
In some cases, complications of vagus nerve stimulation can include:

• Pulse generator malfunction or movement, which may require additional surgery
• Worsening of depression
• Suicidal thoughts or behavior

How you prepare

Because vagus nerve stimulation is a relatively new depression treatment, carefully consider the pros and cons before using it. It's not known precisely how stimulation of the vagus nerve may improve depression. The long-term effects of vagus nerve stimulation are still being studied, and not all side effects may be known yet.

Make sure you know what all of your other treatment choices are and that you and your doctor both feel that vagus nerve stimulation is the best option for you. Ask your doctor exactly what you should expect during surgery and after the pulse generator is in place.

Before surgery, your doctor will do a physical examination. You may need blood tests or other tests to make sure you don't have any health concerns that might be a problem. Your doctor will have you start taking antibiotics before surgery to prevent infection. You may need to stop taking certain medications ahead of time, and your doctor may ask you not to eat the night before the procedure. When you set up your surgery appointment, make sure you're clear on exactly what steps you need to take.

What you can expect

During the surgery
Surgery to implant the vagus nerve stimulation device is done either on an outpatient basis, allowing you go to home that same day, or on an inpatient basis, requiring an overnight stay in the hospital. The surgery usually takes one to two hours. You may remain awake but have medication to numb the surgery area (local anesthesia) or you may be unconscious during the surgery (general anesthesia).

The surgery itself doesn't involve your brain. 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 about the size of a stopwatch and runs on battery power. A lead wire is connected to the pulse generator. The lead wire is guided under your skin from your chest up to your neck, where it's attached to the left vagus nerve through a second incision.

After the procedure
The pulse generator is turned on during a visit to your doctor's office a few weeks after surgery. Then it can be programmed to deliver electrical impulses to the vagus nerve at various durations, frequencies and currents. Vagus nerve stimulation usually starts at a low level and is gradually increased, depending on your symptoms and side effects.

Stimulation typically lasts for 30 seconds and occurs every five minutes. You may have some tingling sensations or slight pain in your neck during episodes of nerve stimulation.

You'll be given a hand-held magnetic device so that you can control the stimulation yourself. This enables you to temporarily turn off the vagus nerve stimulation, which may be necessary when you do activities such as public speaking, singing or exercising, or when you're eating if you have swallowing problems.

You must visit your doctor periodically to make sure that the pulse generator is working correctly and that it hasn't shifted out of position.

Results

If vagus nerve stimulation works as hoped, your depression symptoms will improve or go away completely. It may take several months of treatment with vagus nerve stimulation before you notice any improvements in your depression symptoms.

Keep in mind that vagus nerve stimulation generally isn't meant to replace traditional treatments. You may still need to take antidepressant medication or attend psychotherapy appointments, for instance.