Aug. 8, 2011 -- A new study shows that Parkinson’s disease patients treated with deep brain stimulation can expect the technology to control symptoms like tremors for a decade or longer, while other improvements, such as those in speech and balance, may lessen over time.
The impulses are thought to block abnormal signals that cause many of the debilitating symptoms of Parkinson’s, like tremors, slowness, stiffness, and difficulty with speech.
The procedure, which has been used for over a decade, is typically offered to patients when medications no longer help.
The surgery costs between $30,000 and $50,000 but is usually covered by insurance.
“About 90,000 people now worldwide have received deep brain stimulation for Parkinson’s disease,” says study researcher Andres M. Lozano, MD, PhD, professor and chairman of neurosurgery at the University of Toronto. “The issue is, how long do the benefits last?”
Timeline for the Benefits of Deep Brain Stimulation
To find out, researchers checked on a group of 18 Parkinson’s patients who were first fitted with deep brain stimulators at Toronto Western Hospital between 1996 and 2000.
Patients were videotaped as they performed a series of physical movements.
The patients were tested before their original surgeries, one and five years after surgery, and in the latest study, after 10 years.
Patients were tested under four different conditions: off their medications and with their brain stimulators turned off; off their medications and with their stimulators turned on; on medication and without stimulation; and on both medication and brain stimulation.
The videos were scored by a doctor who wasn’t told which condition the patients were in.
After 10 years, researchers saw that the patients were still seeing improvements with the help of their devices.
When the patients weren’t taking medication, and even after using the technology for a decade, deep brain stimulation improved overall movement by 25%, improved tremor by more than 85%, and improved slowness by 23%, compared to how well they moved with their stimulators off.
And when researchers compared their results to the kinds of improvements the patients had seen in years past, they found some benefits appeared to be longer lasting than others.
“The benefits in some aspects were quite durable, including the benefits to the tremor and slowness of movement called bradykinesia,” Lozano tells WebMD. “Standing and walking, posture, balance and speech, those things got worse with time.”
Over time, people in the study saw their speech get slightly worse. The ability to get up from a chair initially improved on brain stimulation, but after five years, the effect had largely worn off, and after a decade, people were slightly worse off when rising from a chair than they were before their had their stimulators implanted.
Posture and walking showed similar patterns of improvement after one year, with a return to original symptoms after a decade.
“Now the next challenge is to work on those things like balance, gait, and so on, that we were not able to help in the long run, try to understand what causes those problems and try to help those,” says Lozano, who is a paid consultant for the company that makes the deep brain stimulation devices.
The study is published in the Archives of Neurology.
What Patients Can Expect
Experts who were not involved in the research say it echoes the kinds of results they’ve seen in their own patients.
“I personally have been following patients of my own for 12 or 13 years, and I’ve been seeing similar things” says Alon Mogilner, MD, PhD, chief of functional and restorative neurosurgery at Cushing Neuroscience Institutes at The North Shore-LIJ Health System in Great Neck, N.Y.
“What I always tell patients is, ‘whatever symptoms it treats within the first year or so it will continue to treat,’” Mogilner says. "'You may need adjustments over time, and you may develop other symptoms that the DBS [deep brain stimulation] can’t treat,'" he says.
Other experts agreed.
“There are certain things it will treat dramatically, like the tremors. It will also help slowness and stiffness, and we’re able to reduce medications significantly,” says Michael Rezak, MD, PhD, director of the Movement Disorders Center at Central DuPage Hospital in Winfield, Ill.
Reducing medications, he says, can also help reduce some of the worst side effects, including sleepiness, confusion, and hallucinations.
“It does a great job when medicines will not do such a great job anymore,” Rezak says. “It’s got a time and a place. It will open the window of benefit for patients for their symptoms, but it’s not going to be a cure.”