Deep brain stimulation for depression

Definition

Deep brain stimulation involves implanting electrodes within the part of your brain that affects mood. During deep brain stimulation, electrical impulses transmitted through the electrodes deep within the brain affect brain cells and chemicals to relieve depression. The amount of stimulation delivered by the electrodes is controlled by a pacemaker-like device placed under the skin in your upper chest. A wire that travels under your skin connects the device, called a pulse generator, to the electrodes in your brain.

Although it's approved for other conditions, deep brain stimulation for depression hasn't been approved by the Food and Drug Administration (FDA). It's still being studied as an experimental treatment. Most candidates for deep brain stimulation are participants in clinical trials.

Why it's done

Deep brain stimulation is an established treatment for essential tremor and Parkinson's disease. Some people with Parkinson's who underwent deep brain stimulation reported an improved mood. Because of those results, deep brain stimulation is being studied as a possible depression treatment to be used when standard treatments don't work. Standard treatments include antidepressants, psychological counseling (psychotherapy) and electroconvulsive therapy (ECT).

Sending electrical impulses to areas of the brain linked with mood affects brain cells and brain chemistry. While this can help ease depression symptoms, researchers are still investigating exactly how deep brain stimulation improves mood.

Deep brain stimulation also shows some promise for some other mental illnesses. It has been approved by the Food and Drug Administration (FDA) as a treatment for severe and debilitating obsessive compulsive disorder (OCD). It's also being investigated to see whether it may help with Tourette syndrome, chronic pain and other disorders.

Although initial results are promising, more research is needed to determine whether deep brain stimulation can be considered a safe and effective treatment for depression. Researchers are still trying to identify the best locations for the electrode implants to help reduce symptoms while causing the least side effects.

Risks

Although deep brain stimulation is generally safe, any type of surgery carries risks and complications can occur. Also, the brain stimulation itself may cause side effects.

Surgery risks
Deep brain stimulation involves boring small holes in the skull to implant the electrodes, and chest surgery to implant the pulse generator. Complications of surgery may include:

• Bleeding in the brain (hemorrhage)
• Stroke
• Infection
• Speech problems
• Breathing problems
• Nausea
• Heart problems
• Incision scarring

With deep brain stimulation, surgery is not a one-time procedure. Pulse generator batteries have a limited life span and when they run out, symptoms of depression may quickly return. Replacing the dead battery requires surgery to access the pulse generator. Batteries last from six to 18 months. It's also possible for a wire connecting the pulse generator to an electrode to break or for other malfunctions to occur.

Possible side effects after surgery
Side effects associated with deep brain stimulation may include:

• Seizure
• Infection
• Unwanted mood changes, such as mania and depression
• Insomnia
• Allergic reaction to the implant
• Slight paralysis
• Jolting or shocking sensation
• Temporary pain and swelling at the implantation site

How you prepare

Because deep brain stimulation is experimental, it's available only through participation in clinical trials. Because of the risks involved, its use is limited to people who have severe, debilitating depression that hasn't improved with standard treatments. The procedure requires an experienced surgical team.

First, weigh the pros and cons
Deep brain stimulation is a serious and potentially risky procedure. Even if you might be eligible for a clinical trial to test deep brain stimulation, you and your doctors must carefully weigh the risks and potential benefits of the procedure. If your depression prevents you from going about your daily activities or is life-threatening, you may be more willing to face the risks involved with deep brain stimulation. But you still must be screened by a team of medical professionals to make sure deep brain stimulation is a reasonable option for you.

Next, preparing for surgery
Before surgery, you need to have medical tests and a thorough psychiatric examination to make sure that deep brain stimulation is safe for you and is a good option in your case. You may be asked to complete psychological questionnaires or answer a number of questions. You also need brain-imaging studies, such as an MRI, before the surgery, to map the areas of your brain where the electrodes will be implanted.

What you can expect

During the surgery
Because the procedure is experimental for depression, it may not be performed the same way everywhere. In general, here's how surgery for deep brain stimulation works.

• Brain surgery. For the brain surgery portion, you're given local anesthetic to numb the surgery area. You won't need anesthetic in your brain itself, because the brain has no pain receptors. You'll remain awake and alert during the procedure so that the surgeon can talk to you to make sure the proper areas of your brain are being stimulated.

  Your head is placed in a brace to keep it still during surgery. Two small holes are drilled in your skull. Guided by imaging techniques, the surgeon implants electrodes on both sides of your brain. You may undergo testing during the surgery to see how your mood is affected by the stimulation.

• Chest surgery. During the second portion of the surgery, the surgeon implants the pulse generator in your chest, near your collarbone. You're put to sleep with general anesthesia for this surgery. Wires from the brain electrodes are placed under your skin and guided down to the battery-operated pulse generator.

After the procedure
After surgery, you'll need to take antibiotics to lower the risk of infection. A week or so after surgery, the pulse generator in your chest is activated in your doctor's office. The amount of stimulation is customized to your situation, based on your mood and side effects.

Stimulation is generally constant, 24 hours a day. The pulse generator can be easily programmed from outside your body with a hand-held magnetic device you're given to use. With this, you can temporarily turn off stimulation by holding the magnet over the area of your chest where the pulse generator is implanted. When you move the magnet away, stimulation restarts.

You must remain in close contact with your surgeon or other specialist involved, to make sure that the pulse generator is working correctly. You may also need to continue standard depression treatments, such as taking antidepressants.

Deep brain stimulation

Deep brain stimulation

Deep brain stimulation involves implanting an electrode deep within your brain. The amount of stimulation delivered by the electrode is controlled by a pacemaker-like device placed under the ...

Results

If deep brain stimulation works, your depression symptoms will improve or go away completely. It may take several months of treatment with deep brain stimulation before you notice improvements in your depression symptoms. Not everyone with chronic depression, especially those who have had depression for years, gets better with deep brain stimulation.