By Amanda Gardner
TUESDAY, Jan. 6 (HealthDay News) -- The largest study of its kind finds that deep brain stimulation improves both physical function and quality of life after six months in patients with Parkinson's disease.
Deep brain stimulation (DBS) performed better than currently available drug treatments, but it did carry some risks, including one death, according to a study in the Jan. 7 issue of the Journal of the American Medical Association.
"This basically corroborates what has largely emerged over the last decade from literature and clinical experience showing pretty dramatically the potential benefit of DBS for Parkinson's," said Dr. Fred Marshall, medical director of the deep brain stimulation program at the University of Rochester Medical Center, in New York.
Despite abundant clinical experience, there have been few controlled trials on the topic, added colleague Dr. Irene Richard, an associate professor of neurology and psychiatry at the University of Rochester Medical Center. "This is corroborative, that surgery is helpful, but it is associated with more risk."
Deep brain stimulation, approved for Parkinson's by the U.S. Food and Drug Administration in 2002, is relatively widely used in patients with advanced Parkinson's who are no longer being helped by drugs.
"First-line medication works quite well for some window of time, occasionally one's whole life, but typically, a patient takes more and more medications more often. Their life is ruled by medication to maintain a decent function," said study co-author Dr. William J. Marks Jr., an associate professor of neurology at the University of California, San Francisco, and director of the San Francisco VA Parkinson's Disease Research, Education & Clinical Center.
Marks has served as a consultant to Medtronic, the manufacturer of the DBS device, as have other members of the study team. The trial was funded by the VA, the U.S. National Institute of Neurological Disorders and Stroke, and Medtronic.
As Parkinson's advances, motor symptoms are often accompanied by anxiety, depression and other non-motor symptoms.
Generally, DBS, a procedure which involves placing a thin wire that can carry electrical currents deep within the brain, is performed after patients are already failing on their medications.
For this study, 255 Parkinson's patients were randomized to receive either DBS or "best medical therapy." One-quarter of the participants were 70 or older, a population underrepresented in previous trials.
DBS was targeted either to the subthalamic nucleus (same as current practice) or to the globus pallidus; results of that comparison are forthcoming.
After six months, participants in the DBS arm gained about 4.6 hours per day of "on time," meaning time without troubling movement problems, compared with no gain for patients on best medical therapy.
Seventy-one percent of DBS patients, and only 32 percent of patients in the control group, experienced "clinically meaningful motor function improvements." Those receiving DBS also reported improvements in quality of life.
However, at least one serious adverse event occurred in 49 of the DBS patients vs. 15 in the other group.
Those receiving DBS also experienced small problems with cognitive functioning similar to patterns seen in previous studies and had more falls resulting in fractures and other injuries.
Although both younger and older patients gleaned similar benefits from DBS, older patients were more prone to adverse effects.
This "landmark" study, said Marks, "proved superior for such patients, rather than a tweak-and-adjustment [of medications] approach."
Hopefully, he added, the findings will encourage more neurologists to consider DBS for appropriate patients.
"I think this is going to spur those people who have still been on the fence about DBS to feel comfortable with it," Marshall said.
"This study, to me, confirms the tremendous usefulness of the procedure in spite of the warning, of course, that there were certain adverse effects," said Dr. Carlos Singer, director of the Parkinson's Disease Center and a professor of neurology at the University of Miami Miller School of Medicine. "It means that we have to continue refining our selection of patients. You don't want to be overzealous in picking up patients . . . take into account that the surgery was not effective for everybody."