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Study Shows Surgery Called Deep-Brain Stimulation Treats Symptoms of Parkinson's Disease
By Salynn Boyles
WebMD Health News
Reviewed By Brunilda
on Wednesday, August 30, 2006
Aug. 30, 2006 -- New research shows that the surgical procedure known as deep-brain stimulation is a more effective treatment for many patients with Parkinson's disease than drug therapy alone.
Patients under the age of 75 who had the surgery were better able to function physically and socially six months later than other patients of similar age -- and with similar symptoms -- who remained on the drug treatment.
The German study was one of the first to consider quality of life as a treatment end point. Patients treated with deep-brain stimulation plus Parkinson's medications had quality-of-life scores that were 25% higher six months later than patients treated with drugs alone, researcher Jens Volkmann, MD, PhD, tells WebMD.
The study is published in the Aug. 31 issue of The New England Journal of Medicine.
"That may not sound like a lot, but if you look at the other studies that included this end point, there are very, very few treatments for Parkinson's disease that have been shown to have any impact on quality of life," he says. "A 25% improvement is unparalleled."
Although it is still a relatively new procedure for the treatment of Parkinson's disease, deep-brain stimulation is now performed at more than 200 treatment centers in the U.S.
Often described as a pacemaker for the brain, the
procedure involves the surgical implantation of very thin electrodes which
deliver electrical impulses to the parts of the brain that control movement. A
pacemaker-like device (a small electrical device called a pulse generator) is
implanted under the skin of the chest; it can be controlled by the patient using
a remote control or magnet.
Who's a Good Surgery Candidate?
Deep-brain stimulation is most often used to relieve the tremors and alleviate other symptoms of Parkinson's disease -- such as slowness of movement -- when they can no longer be adequately controlled with medications alone.
But not everyone is a candidate for the surgery, and its success depends on careful selection of patients, National Parkinson's Foundation medical director Michael Okun, MD, tells WebMD.
"Many patients who could benefit from this treatment are not getting it," he says. "And conversely, some patients who are not good candidates are having the surgery."
The study by Volkmann and colleagues from the German Parkinson Study Group included 156 patients with advanced Parkinson's disease and severe movement problems. They were randomly assigned to receive the best available drug therapy or deep-brain stimulation with drug treatments given in modified doses.
Most drug therapy used to treat Parkinson's replenishes the brain's dopamine levels. Other treatments work by mimicking dopamine, a chemical involved in movement.
All the patients in the study were younger than 75, and their average age was 60. Patients with dementia , those who had very poor response to the dopamine drug L-dopa, or those who were unsuitable for surgery for other medical reasons, were excluded.
Careful Screening Critical
Okun points out that the study participants were younger than the typical patient who is considered for surgery in the U.S., and they were very carefully screened -- all factors, he says, which undoubtedly played a role in their good response.
He adds that evaluation by a team of various specialists is an essential step for patients being considered for deep-brain stimulation.
The team should include: a neurologist specializing in movement disorders who evaluates patient symptoms both on and off L-dopa treatment; a neuropsychologist who evaluates cognitive performance; a neurosurgeon; and possibly even a psychiatrist.
"Anyone who is considering this surgery needs to be evaluated at a specialized treatment center with this multidisciplinary team in place," he says. "And patients will need multiple adjustments once the device is in place."
SOURCES: Deuschl, G. The New England Journal of Medicine, Aug. 31, 2006; vol 355: pp 896-908. Jens Volkmann, MD, PhD, German Parkinson Study Group, neurostimulation section. Michael Okun, MD, University of Florida Movement Disorders Center, Gainesville, Fla.; medical director, National Parkinson's Foundation.
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