Alzheimer's, Dementia & Mental Health
Seniors, Other Parkinson Patients Gain from Deep
Brain Stimulation but Take Serious Risk
Few previous randomized trials comparing treatments,
most excluded senior citizens
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Study participant
Richard Seeger tells his experience.
See
Video |
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Jan. 7, 2009 - Patients with advanced Parkinson disease (PD) – 25
percent of them age 70 or older - 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
they also had a higher risk of a serious adverse event, according to a
study in today’s issue of the Journal of the American Medical
Association (JAMA).
The United States' aging population has made
Parkinson Disease an increasingly prevalent disease, with symptoms that
can include tremors, muscle stiffness and an inability to move.
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 (60) or
● globus pallidus (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 gradual
decereases in some areas of information processing for patients
receiving deep brain stimulation, rather than best medical therapy.
Serious Adverse Events
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, according to
the researchers.
“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: Many Questions Still Unanswered
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.
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About
Parkinson's Disease
Also called: Paralysis agitans, Shaking palsy
Parkinson's disease is the
second most common chronic neurological disorder in older adults
after Alzheimer's, affecting approximately one percent of people
over age 60. Approximately 15 percent of patients develop
Parkinson's disease before the age of 50.
Every nine minutes someone is
diagnosed with Parkinson's disease.
Parkinson's disease is
a disorder that affects nerve cells, or neurons, in a part of
the brain that controls muscle movement. In Parkinson's, neurons
that make a chemical called dopamine die or do not work
properly. Dopamine normally sends signals that help coordinate
your movements. No one knows what damages these cells. Symptoms
of Parkinson's disease may include:
● Trembling of hands, arms, legs, jaw and face
● Stiffness of the arms, legs and trunk
● Slowness of movement, shuffling gait
● Poor balance and coordination
● Loss of
facial expression
As symptoms get worse
over time, people with the disease may have trouble walking,
talking or doing simple tasks. They may also have problems such
as depression, sleep problems or trouble chewing, swallowing or
speaking.
Although Parkinson's
usually begins around age 60, it can start earlier. It is more
common in men than in women. There is no cure for Parkinson's
disease. A variety of medicines sometimes help symptoms
dramatically.
>>
More on Parkinson's at MedlinePlus
According to the National Parkinson
Foundation, 1.5 million Americans currently have the
degenerative illness, which strikes men and women in roughly
equal numbers, usually after the age of 65.
>>
More at NPF |
"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."
More links to
archived news reports about Parkinson's
Parkinson’s Disease Risks Lower with High Levels of
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June 22, 2007
Engineers Say They Now Know How Brain Pacemakers
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thousands
May 31, 2007
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Australians Claim Low-Cost Gene Screening for
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Feb. 23, 2007
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December 20, 2006
Cell Activities that
Protect against Alzheimer's Protein Buildup Found
Findings may lead to new therapies for
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Researchers find 'Probable Cause' for Parkinson's,
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June 28, 2006
