GAINESVILLE, Fla. – Researchers from the University of
Florida and 14 additional medical centers reported results today in the online
version of The Lancet Neurology journal indicating that deep brain stimulation
– also known as DBS – is effective at improving motor symptoms and quality of
life in patients with advanced Parkinsons disease.
The study, sponsored by St. Jude Medical Inc., tested the
safety and effectiveness of a constant current DBS device developed by St. Jude
Medical to manage the symptoms of Parkinsons disease. The device aimed to
reduce tremors, improve the slowness of movement, decrease the motor disability
of the disease and reduce involuntary movements called dyskinesia, which are a
common side effect of Parkinsons drugs.
After treatment, analysis of 136 patient diaries revealed
longer periods of effective symptom control – known as “on time” – without
involuntary movements. “On time” for patients who received stimulation
increased by an average of 4.27 hours compared with an increase of 1.77 hours
in the group without stimulation. Patients also noted overall improvements in
the quality of their daily activities, mobility, emotional state, social
support and physical comfort.
“I think it is safe to say since dopamine treatment emerged
in the 1960s, DBS has been the single biggest symptomatic breakthrough for
Parkinson patients who have experienced the fluctuations associated with
levodopa therapy,” said Michael S. Okun, M.D., first author of the study,
administrative director of the UF College of Medicines Center for Movement
Disorders and Neurorestoration, and the National Medical Director for the
National Parkinson Foundation. “This study validates the use of mild electrical
currents delivered to specific brain structures in order to improve Parkinsons
disease in select patients with advanced symptoms, and additionally, it
explored a new stimulation paradigm. Future improvements in devices and the
delivery systems for DBS will hopefully provide exciting new opportunities for
Parkinsons sufferers.”
Only patients who have had Parkinsons disease for five
years or more were included in the study. They were randomly assigned to a
control group that delayed the onset of stimulation for three months, or a
group whose stimulation began shortly after surgery. All patients were followed
for 12 months.
The deep brain stimulation procedure involves surgeons
implanting small electrodes into an area of the patients brain that controls
movement. The electrodes are connected to a device precisely programmed to use
mild electrical current to modulate problematic brain signals that result in
movement problems.
Todays voltage-controlled DBS devices deliver pulses of
current that vary slightly with surrounding tissue changes. The DBS devices
tested in this study are intended to provide more accurate delivery and control
of the electrical pulses.
“We are committed to driving research that will provide
solutions for physicians and their patients whose needs are currently unmet,”
said Rohan Hoare, president of St. Jude Medical Neuromodulation Division.
“These results are significant as they offer evidence that stimulation with the
Libra constant current system enabled patients to have better motor control and
an improvement in their quality of life when compared to the control group.”
The U.S. Food and Drug Administration approved the use of
DBS for Parkinsons disease in 2002. At least 500,000 people in the United States
suffer from Parkinsons with about 50,000 new cases reported annually, according
to the National Institute of Neurological Disorders and Stroke. These numbers
are expected to increase as the average age of the population rises.
“The study answered some very important questions concerning
cognition and mood with lead implantation (alone) versus implantation with
stimulation. It also refutes the hypothesis that DBS increases depressive
symptoms,” said Gordon H. Baltuch, M.D., Ph.D., a professor of neurosurgery in
the Perelman School of Medicine at the University of Pennsylvania
and a study author. “The groups results also showed a decrease in the
infection rate to 4 percent from previously published 10 percent. It shows that
American neurosurgeons and neurologists with their industry partners are
improving the safety of this procedure and working in a collaborative fashion.”
Comparable with other large DBS studies, the most common
serious adverse event revealed was infection, which occurred in five patients.
Likewise, some participants also reported an increase in the occurrence of
slurred speech, known as dysarthria.
“Technology is on the move, and we expect to see continued
improvements to DBS approaches, equipment and materials,” said Okun, who is
also affiliated with UFs McKnight Brain Institute. “DBS has set the bar high for
the development of new therapies for advanced Parkinsons disease patients. DBS
will be the standard of care gene therapy and other cell-based therapies that
are now being conceived will be measured against, and this will hopefully
translate into significant improvements in what we can offer our patients.”
In addition to UF and Penn, research was conducted at
centers affiliated with Baylor College of Medicine, Columbia University Medical
Center, Lahey Clinic, Loma Linda University Medical Center, the Medical College
of Wisconsin, Mount Sinai Medical Center, Oakwood Hospital and Health Systems,
Texas Health Presbyterian, Rush University Medical Center, the University of
Miami, the University of Rochester and the University of Virginia Health
Systems.
Posted by Sean Fenske, Editor-in-Chief, MDT