Trial provides insight on Parkinson's treatment
Two target sites for ‘deep brain stimulation' both prove effective
June 17, 2010
Study results from VA and the National
Institutes of Health show that deep
brain stimulation (DBS)—a surgical
treatment that dramatically improves
movement-related symptoms for many
patients with Parkinson's disease—works
equally well at either of two sites in the
brain. The findings appeared June 3 in the
New England Journal of Medicine.
The new findings are the latest from a
major study initially published last year in
the Journal of the American Medical
Association. The trial, conducted at seven
VA sites and six university hospitals, found
that DBS is somewhat riskier than carefully
managed drug therapy but may offer
significant improvement for those with
advanced Parkinson's who no longer
respond well to medication alone. Most
DBS patients in the study were able to
reduce their medication substantially.
The new report is based on a two-year
comparison of outcomes in 299 patients
who underwent DBS. It shows that
stimulation of either of the two brain
regions normally targeted in DBS can
effectively control motor symptoms and
boost quality of life.
About Parkinson's
In DBS, surgeons implant electrodes in
the brain and run thin wires under the skin
to a pacemaker-like device placed under the
skin near the collarbone. Electrical
stimulation from the battery-operated device
jams the brain signals that cause motor
symptoms such as stiffness and tremors.
Thousands of Americans have had DBS
since it was introduced a few years ago, and
many have reported major improvements.
But questions have remained about which
stimulation site in the brain yields better
outcomes.
Earlier studies suggested that better
motor control could be achieved by
stimulating the subthalamic nucleus (STN)
rather than the globus pallidus interna
(GPi)—two areas of the brain involved in
movement. On the other hand, GPi
stimulation was found to possibly pose less
risk of side effects such as depression or
impaired thinking.
The new VA-NIH analysis finds both
sites roughly equal for motor outcomes.
There were subtle differences between the
sites in terms of cognitive skills and
mood—mainly in line with past research
findings—but the full clinical significance
of the differences is not yet clear.
Serious adverse events occurred equally
across both groups. The most common
problem was surgical-site infection,
occurring in fewer than 10 percent of
patients in both groups. Almost all the
adverse events were resolved over the twoyear
study period. One surgery-related death
was reported, stemming from a brain
hemorrhage.
Lead author Kenneth Follett, MD, PhD,
of the Iowa City VA Medical Center said
that overall, "Physicians and patients can
have confidence in both types of DBS” as
being effective for motor improvement. He
said doctors should also consider the subtle
differences that emerged in the comparison
in other areas—for example, mood,
cognition, or medication use—when making
DBS treatment decisions with patients. The
best candidates for the procedure, he said,
are patients who have ongoing problems
with movement despite medication or who
suffer troubling side effects from the drugs,
and who do not have significant cognitive
problems or contraindications to surgery.
Patients who took part in the VA-NIH
trial will be followed for several more years
so researchers can further tease out the
relative benefits of each DBS approach.
The study was sponsored by VA's
Cooperative Studies Program and the
National Institute of Neurological Disorders
and Stroke, part of NIH.
This article originally appeared in the
June 2010 issue of VA Research Currents.