Deep brain stimulation (DBS) involves implanting electrodes within certain areas of the brain. These electrodes produce electrical impulses that regulate abnormal impulses. Or the electrical impulses can affect certain cells and chemicals within the brain.

The amount of stimulation in deep brain stimulation is controlled by a pacemaker-like device placed under the skin in your upper chest. A wire that travels under your skin connects this device to the electrodes in your brain.

Deep brain stimulation is commonly used to treat a number of conditions, such as:

• Parkinson's disease
• Essential tremor
• Dystonia
• Epilepsy
• Obsessive-compulsive disorder

Deep brain stimulation is also being studied as a potential treatment for:

• Tourette syndrome
• Huntington's disease and chorea
• Chronic pain
• Cluster headache

Deep brain stimulation is an established treatment for people with movement disorders, such as essential tremor, Parkinson's disease and dystonia, and psychiatric conditions, such as obsessive-compulsive disorder. It's also approved for use by the Food and Drug Administration to reduce seizures in difficult-to-treat epilepsy.

This treatment is reserved for people whose symptoms aren't controlled with medications.

Although deep brain stimulation is generally considered to be low risk, any type of surgery has the risk of complications. Also, the brain stimulation itself can cause side effects.

Surgery risks

Deep brain stimulation involves creating small holes in the skull to implant the electrodes into the brain tissue as well as performing surgery to implant the device that contains the batteries under the skin in the chest. Complications of surgery may include:

• Misplacement of leads
• Bleeding in the brain
• Stroke
• Infection
• Breathing problems
• Nausea
• Heart problems
• Seizure

Possible side effects after surgery

Side effects associated with deep brain stimulation may include:

• Seizure
• Infection
• Headache
• Confusion
• Difficulty concentrating
• Stroke
• Hardware complications, such as an eroded lead wire
• Temporary pain and swelling at the implantation site

A few weeks after the surgery, the device will be turned on and the process of finding the best settings for you begins. Some settings may cause side effects, but these often improve with further adjustments of your device.

Because there have been infrequent reports that the DBS therapy affects the movements needed for swimming, the Food and Drug Administration recommends consulting with your doctor and taking water safety precautions before swimming.

Possible side effects of stimulation

• Numbness or tingling sensations
• Muscle tightness of the face or arm
• Speech problems
• Balance problems
• Lightheadedness
• Vision problems, such as double vision
• Unwanted mood changes, such as anger and depression

First, weigh the pros and cons

Deep brain stimulation is a serious and potentially risky procedure. Even if you might be eligible for deep brain stimulation, you and your doctors must carefully weigh the risks and potential benefits of the procedure.

Next, prepare for surgery

Before surgery, you'll likely need medical tests to make sure that deep brain stimulation is a safe and appropriate option for you. You may also need brain-imaging studies, such as an MRI, before the surgery. These studies help to map the areas of your brain that will have the electrodes implanted.

During the surgery

In general, here's how surgery for deep brain stimulation works:

• Brain surgery. For the brain surgery portion, your care team fits you with a special head frame to keep your head still during the procedure (stereotactic head frame). Then, team members use neuroimaging (brain MRI or CT) to map your brain and identify the area in your brain where they'll place the electrodes.

  In most cases, the electrodes will be placed while you're awake and alert. This is to be sure the effects of stimulation can be tested fully. If you're awake for surgery, you'll be given a local anesthetic to numb your scalp before the procedure, but you won't need an anesthetic in your brain itself because the brain has no pain receptors. In some cases, surgery can be done under general anesthesia so that you'll be unconscious.

  Your surgeon implants a thin wire lead with a number of contacts (electrodes) at the tips into a specific area of your brain. Or one lead is implanted into each side of the brain (for a total of two leads). A wire runs under your skin to a pulse generator (neurostimulator) implanted near your collarbone.

  During surgery, both the neurologist and the surgeon carefully monitor your brain to help ensure correct electrode placement.

• Chest wall surgery. During the second portion of the surgery, the surgeon implants the part of the device that contains the batteries (pulse generator) under the skin in your chest, near your collarbone.

  General anesthesia is used during this procedure. Wires from the brain electrodes are placed under your skin and guided down to the battery-operated pulse generator.

  The generator is programmed to send continuous electrical pulses to your brain. You control the generator, and you can turn it on or off using a special remote control.

After the procedure

A few weeks after surgery, the pulse generator in your chest is activated in your doctor's office. The doctor can easily program your pulse generator from outside your body using a special remote control. The amount of stimulation is customized to your condition, and may take as long as four to six months to find the optimal setting.

Stimulation may be constant, 24 hours a day, or your doctor may advise you to turn your pulse generator off at night and back on in the morning, depending on your condition. You can turn stimulation on and off with a special remote control that you'll take home with you. In some cases, your doctor may program the pulse generator to let you make minor adjustments at home.

The battery life of your generator varies with usage and settings. When the battery needs to be replaced, your surgeon will replace the generator during an outpatient procedure.

Deep brain stimulation won't cure your disease, but it may help lessen your symptoms. If deep brain stimulation works, your symptoms will improve significantly, but they usually don't go away completely. In some cases, medications may still be needed for certain conditions.

Deep brain stimulation isn't successful for everyone. There are a number of variables involved in the success of deep brain stimulation. It's important to talk with your doctor before surgery about what type of improvement you can expect for your condition.