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Deep Brain Stimulation Treatment For Advanced Parkinson's Disease Patients 
Provides Benefits, Risks
ScienceDaily (Jan. 9, 2009) - Patients with advanced Parkinson disease (PD) 
who received deep brain stimulation treatment had more improvement in 
movement skills and quality of life after six months than patients who 
received other medical therapy, but also had a higher risk of a serious 
adverse events, according to a new study.
Deep brain stimulation is a surgical treatment involving the implantation of 
electrodes that send electrical stimulation to specific parts of the brain 
to reduce involuntary movements and tremors. It is the surgical intervention 
of choice when PD motor (movement) complications are inadequately managed 
with medications, according to background information in the article. 
"However, recent reports highlighting unexpected behavioral effects of 
stimulation suggest that deep brain stimulation, while improving motor 
function, may have other less desirable consequences," the authors write. 
They add that there are few randomized trials comparing treatments, and most 
studies exclude older patients.
Frances M. Weaver, Ph.D., of Hines VA Hospital, Hines, Ill., and colleagues 
conducted a randomized trial to compare the benefits and risks of deep brain 
stimulation with those of best medical therapy for patients, of a wide age 
range, with PD. A total of 255 patients with PD were enrolled; 25 percent 
were age 70 years or older. The participants were randomized to receive 
bilateral deep brain stimulation with leads of the stimulation device 
implanted in the following locations of the brain: subthalamic nucleus (n = 
60) or globus pallidus (n = 61); or received best medical therapy (n = 134), 
which included management by movement disorder neurologists, who monitored 
medication use and nonpharmacological therapy (e.g., physical, occupational, 
and speech therapy).
The researchers found that at 6 months, deep brain stimulation patients 
gained an average of 4.6 hours per day of on time (the time of good symptom 
control or unimpeded motor function) without troubling dyskinesia 
(involuntary movements), while the average change for the best medical 
therapy group was 0 hours. Motor function improved significantly with deep 
brain stimulation compared with best medical therapy, with 71 percent of 
deep brain stimulation patients vs. 32 percent of best medical therapy 
patients experiencing clinically meaningful motor function improvements at 6 
months, while 3 percent of deep brain stimulation patients and 21 percent of 
best medical therapy patients had clinically worsening scores.
Compared with patients in the best medical therapy group, patients in the 
deep brain stimulation group experienced significant improvements in the 
summary measure of quality of life and on 7 of 8 PD quality-of-life scores. 
Neurocognitive testing revealed small decrements in some areas of 
information processing for patients receiving deep brain stimulation vs. 
best medical therapy.
The overall risk of experiencing a serious adverse event was 3.8 times 
higher in deep brain stimulation patients than in best medical therapy 
patients. Forty-nine deep brain stimulation patients (40 percent) 
experienced 82 serious adverse events. Fifteen best medical therapy patients 
(11 percent) experienced 19 serious adverse events. The most common serious 
adverse event was surgical site infection, with other serious adverse events 
including nervous system disorders, psychiatric disorders, device-related 
complications and cardiac disorders.
"The clinical significance of the adverse events and minor neurocognitive 
changes observed in patients in the deep brain stimulation group and, more 
importantly, whether patients who undergo deep brain stimulation view 
improvement in motor function and quality of life as outweighing adverse 
events, remain to be explored. More detailed analyses of adverse events and 
neurocognitive functioning following the conclusion of phase 2 of this study 
will shed light on these issues. Caution should be exercised, however, 
against overstating or understating the risks of deep brain stimulation for 
patients with PD. Physicians must continue to weigh the potential short-term 
and long-term risks with the benefits of deep brain stimulation in each 
patient," the authors conclude.
Editorial: Neurostimulation for Parkinson Disease
In an accompanying editorial, Günther Deuschl, M.D., Ph.D., of the 
Universitätsklinikum Schleswig-Holstein, Kiel, Germany, comments on the 
findings of Weaver and colleagues.
"Although deep brain stimulation is the most important innovation for 
treatment of advanced PD since the discovery of levodopa [drug used to treat 
PD], many questions are still unanswered. For instance, the optimal timing 
for the implantation is unknown. The majority of patients undergo deep brain 
stimulation surgery more than 10 years after disease onset when the patients 
are already incapable of working and when the disease-related psychosocial 
decline has already begun. As quality of life is improved with this 
treatment it may improve psychosocial functioning in general for these 
advanced stages. With the aging of the general population, PD will become 
even more common and patients with PD will get older. Therefore, the present 
results showing similar efficacy and tolerability of deep brain stimulation 
in younger and older patients must be replicated because it is at variance 
with some other reports demonstrating lower rates of operative and 
postoperative complications in younger patients."
"Overall the results of this important study by Weaver et al have 
convincingly confirmed the 6-month efficacy of deep brain stimulation for 
advanced PD in the largest patient group studied thus far. However, this 
study, along with previous research on this therapy, shows that such 
progress cannot be made without costs in terms of adverse effects."

JAMA and Archives Journals (2009, January 9). Deep Brain Stimulation 
Treatment For Advanced Parkinson's Disease Patients Provides Benefits, 
Risks. ScienceDaily. Retrieved January 10, 2009, from 
http://www.sciencedaily.com­ /releases/2009/01/090106161510.htm

Rayilyn Brown
Director AZNPF
Arizona Chapter National Parkinson Foundation
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