Deep brain stimulation treatment improves movement skills in
15 January 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 study JAMA.
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, PhD, 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 (eg, 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% of deep brain stimulation
patients vs. 32% of best medical therapy patients experiencing
clinically meaningful motor function improvements at 6 months, while 3%
of deep brain stimulation patients and 21% 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%)
experienced 82 serious adverse events. Fifteen best medical therapy
patients (11%) 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.
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