Deep brain stimulation involves implanting electrodes within certain areas of your 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 used to treat a number of neurological conditions, such as:

  • Essential tremor
  • Parkinson's disease
  • Dystonia

Deep brain stimulation is also being studied as an experimental treatment for epilepsy, cluster headaches, Tourette syndrome, chronic pain and major depression. Many candidates for deep brain stimulation are participants in clinical trials.

Deep brain stimulation is an established treatment for movement disorders, such as essential tremor, Parkinson's disease, and dystonia, and more recently, obsessive-compulsive disorder. This treatment is usually reserved for people who aren't able to get control of their symptoms with medications.

Although deep brain stimulation is generally safe, any type of surgery has the risk of complications. 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 surgery to implant the device that contains the batteries under the skin in the chest. Complications of surgery may include:

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

With deep brain stimulation, surgery isn't a one-time procedure. The batteries that are implanted in the chest have a limited life span, and when they run out, your symptoms may quickly return. Replacing the batteries requires another surgery. It's also possible for a wire connecting the batteries 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
  • Headache
  • Insomnia
  • Memory problems
  • 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. This process may take several months. Some settings may cause side effects, but these often improve with further adjustments of your device.

Possible side effects of stimulation

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

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, preparing for surgery

Before surgery, you need to have medical tests to make sure that deep brain stimulation is safe for you and is a good option in your case. 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.

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, they use magnetic resonance imaging (MRI) to map your brain and identify the area in your brain where they'll place the electrodes. You'll be given a local anesthetic to numb your scalp before surgery. You won't need an anesthetic in your brain itself because the brain has no pain receptors.

    Your surgeon implants a thin wire lead with four contacts (electrodes) at the tips into a specific area of your brain. A wire runs under your skin to a generator (neurostimulator) implanted near your collarbone.

    You'll remain awake and alert during the procedure so that your neurologist can talk to you to make sure the right areas of your brain are being stimulated. Your responses help your health care team place the lead in the correct place while minimizing side effects. During surgery, both the neurologist and 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. This usually occurs a few days after the brain surgery. 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

After surgery, you'll need to take antibiotics to lower the risk of infection. A few weeks after surgery, the pulse generator in your chest is activated in your doctor's office. The doctor can be easily program your pulse generator from outside your body using a special remote control. The amount of stimulation is customized to your condition.

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. The battery may last between three and five years. When the battery needs to be replaced, your surgeon will replace the generator during an outpatient procedure.

You must remain in close contact with your surgeon and neurologist to make sure that the pulse generator is working correctly.

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.

Jan. 10, 2013