Parkinson's disease (PD) is classified as a chronic and progressive movement disorder. Dopamine is a chemical produced by certain cells in the body (substantia nigra). Because of a deficiency of dopamine in the brain that occurs when the substantia nigra go "haywire" and die, people who have Parkinson's develop abnormal movements and coordination throughout their bodies. Medications can be used to control some of the tremors and stiffness that are common symptoms, but sometimes drugs are not adequate. Deep brain stimulation, or DBS, is a type of surgery that is an effective treatment for some Parkinson's patients.
History
Surgical treatment has existed for Parkinson's disease for more than a half century, according to the Parkinson's Disease Foundation. Pallidotomy and thalamotomy, two procedures that kill cells in the brain that in effect create some of the symptoms of Parkinson's disease, have been practiced since the 1950s. In the early 1990s, deep brain stimulation became another option. A French physician named Alim-Louis Benabid delivered electric stimulation to a patient's brain instead of destroying cells, and realized that in the process, the patient's tremors were terminated. The DBS procedure was approved by the FDA in 1997 and 2002 for treatment on one side and both sides of the brain, respectively.
Candidacy
Parkinson's disease affects each person differently, with a wide range of symptoms. Some patients experience what are called primary motor symptoms, including tremors, rigidity of the muscles and a slowed movement, called bradykinesia. Others may experience secondary symptoms such as slurred speech, difficulty with fine motor skills, and a loss of facial expressions. Parkinson's also can affect cognitive function. Deep brain stimulation is most effective for those who experience tremors and who do not show cognitive symptoms like dementia. Ideal candidates for DBS will have tried drug therapy and seen that their bodies respond to a drug called levodopa, but maybe not seen results with other medications. The decision to treat Parkinson's disease should be made jointly by the patient and his neurologist.
Procedure
During deep brain stimulation surgery, the surgeon will use MRI technology to find the "targeted region" of the brain that is producing the symptoms of Parkinson's. As many as four electrodes will be placed in the target region through an opening that is created in the patient's skull. The electrodes are powered by a generator unit, called an IPG, which is inserted subcutaneously into the patient's chest, near the collarbone. The IPG contains a long-lasting battery that sends electrical impulses to the brain, which in turn, helps control motor function. The battery is usually not activated until seven days after surgery.
Recovery
DBS is performed while the patient is conscious and under local anesthetic, so that the surgeon can monitor symptoms and see that the electrodes are placed in the right area. Some people with Parkinson's may experience a headache post-surgery, mainly from wearing the head frame that allows the doctors to perform the procedure. Recovery times vary, but most people stay in the hospital for two to three days after receiving DBS. Parkinson's symptoms may be calmer at this time, but the patient may feel very tired for a few days. Patients should schedule a follow-up appointment to remove their stitches and to have the IPG battery activated--a minor surgical procedure that may cause minor pain.
Outcome
The outcome and long-term effectiveness of DBS depends on the individual's overall health--both mental and physical. IPG batteries can last for three to five years and need to be replaced at that time, but the results of the deep brain stimulation may outlast these predictions. The Parkinson's foundation reports that studies show that DBS has a positive effect on tremors and other symptoms for five years or longer in many cases. Jaslok Hospital and Research Center in Mumbai, India, reports that of the 20 DBS operations performed at the hospital in a two-year period, the patients were able to reduce their medication levels significantly because of a decrease in symptoms of up to 70 percent.
Tags: Parkinson disease, brain stimulation, brain that, deep brain, brain stimulation