Brain surgery helps severe Parkinson's
NEW YORK, Oct 14, 1998 (Reuters) -- Patients severely disabled by
Parkinson's disease can reduce or even eliminate their need
for medication by undergoing an operation in which implanted electrodes
are used to stimulate the subthalamic nucleus, a region
of the brain that controls movement.
In a new study on 24 patients, 20 followed for a year had a 60%
improvement in their ability to perform routine activities, and
their average dose of drugs was cut in half in the year after the
procedure, according to a report in the October 15th issue of
The New England Journal of Medicine.
The other four patients were not included in the study for several
reasons, including complications stemming from the procedure
such as infection requiring removal of the electrodes. One patient who
had a brain hemorrhage during surgery, causing long term
paralysis and loss of speech.
However, 4 of the 20 patients who underwent subthalamic nucleus
stimulation (STN) have been able to eliminate their need for
levodopa, the most common drug used to treat Parkinson's disease.
Levodopa, or L-dopa, eventually loses its ability to control
the symptoms of Parkinson's disease and can cause uncontrollable
movements on its own, known as dyskinesia. About 7 million
people around the world have Parkinson's disease, which usually strikes
after age 60, causing progressive tremor, muscle
rigidity and other movement problems.
Eight of the patients had short term mental difficulties, including
confusion, hallucination and disorientation after the surgery
Lead investigator Dr. Pierre Pollak of Joseph Fourier University of
Grenoble and the University Hospital of Grenoble in France
also presented the new data at the 5th International Congress of
Movement Disorders in New York.
``The technique is ``not for everyone,'' Pollack said. There is a 2% to
5% risk of bleeding during the neurosurgery, and only the
most disabled patients are eligible. The ideal candidate is a younger
patient -- average age in this study was 55 at the time of
surgery -- with advanced disease complicated by dyskinesias and motor
fluctuations.
Overall, only 15% of all Parkinson's patients ``will be clearly
improved'' with subthalamic nucleus stimulation, he said.
But unlike levodopa, STN appears to continue working over time. No
tolerance to stimulation appears to develop and five
patients who have been followed the longest -- 5 years -- have had a
stable improvement in symptoms, he said. Of the 70
patients treated with the technique, two have had deterioration in
mental ability. However, both were in early stages of dementia
at the time of surgery, Pollak said, but he acknowledged that there was
a ``speeding of decline associated with surgery.''
SOURCE: The New England Journal of Medicine 1998;339:1105-1111.
--
Judith Richards, London, Ontario, Canada
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