Eight years ago, at 53, Dan Stark decided he needed to make a dramatic change. He was taking 2100 mg of Sinemet (levodopa/carbidopa) a day to try and eke whatever lasting benefits he could out of his medication, with the hopes of getting some relief for his Parkinson’s disease. But severe dyskinesia resulted, essentially “ruling his life.”
Stark had read about a surgical procedure called Deep Brain Stimulation, or DBS, which works by stimulating malfunctioning motor circuits in the brain with electric pulses from a pacemaker-like device, offering real help for those struggling with the motor symptoms of PD and dyskinesia. So he asked his physician about the procedure and made what he now calls the “life-changing decision” to get DBS.
Since 1993, when the first positive study results were published establishing the use of DBS to treat PD and essential tremor, more than 150,000 people like Stark have undergone the procedure worldwide.
Still, DBS is not for everyone. Certain people respond more favourably to the treatment than others. Some are unable to undergo the invasive surgery to implant the DBS device, which usually involves two separate procedures for each side of the brain. Doctors also need to implant the lead and adjust it periodically. And it’s important to remember: DBS treats the symptoms of PD. It is not a cure.
Whom — and how — DBS can help
The mechanism underlying DBS’ therapeutic effect is not clearly understood. (This is not uncommon; the mechanism of action behind many common medical interventions, including aspirin, remains unknown, as DBS pioneer Andres Lozano, MD, PhD, of the University of Toronto, has pointed out.) Scientists continue to evolve in their position on when, and how, the procedure might be most effective.
Physicians have begun, however, to better understand who might be good candidates for DBS, and who might not be. (Of course, you should always consult your physician to make decisions about your own personal treatment regimen.)
Irene Hegeman Richard, MD, a professor of neurology and psychiatry at the University of Rochester School of Medicine and a member of MJFF’s Scientific Advisory Board, provides a high level profile of those who are typically good candidates for the procedure. They usually:
Have idiopathic PD;
Experience an excellent response to levodopa but have developed motor complications, such as wearing-off or dyskinesia;
Do not have an unstable psychiatric condition;
Do have good cognition;
Do not have significant gait/balance problems when “on;” and
Are healthy enough to undergo surgery.
Individuals who might be candidates for DBS must undergo a series of tests from their physician and various specialists in order to determine if they do, in fact, qualify for the procedure.
A long road to optimization
Even for those who are good candidates, and who make the nontrivial decision to have electrodes implanted into the brain, there’s still a long road ahead. The procedure often requires patients to return frequently to their doctor to fine-tune the device. And after all of that, the therapeutic benefit can vary widely.
Stark, for one, noticed only limited therapeutic benefit in the first six months following the surgery. Then he changed doctors and found one who better understood the optimal settings for him — leading to a seven-year period of living almost symptom-free. Now eight years later, he will soon see his doctor to tweak the device, as he has recently noticed some symptoms return.
Evolution, expansion and new questions
Scientists continue working on DBS technology to maximize benefit and minimize complications. The treatment is currently being studied for its possible application earlier in the disease course, as well as its ability to treat non-motor symptoms of PD.
Lozano explains: “While DBS is very effective for the motor signs and symptoms of PD, it is less so for the non-motor and non-dopamine responsive features of the illness. But scientists are hard at work to better understand how DBS might treat these symptoms as well.”
Research has shown that DBS can be effective for a period of 10 years or longer; anything beyond this will push the existing frontier. New issues associated with surgical intervention at an earlier age are likely to surface, explains Lozano, including how the device, and the brain, respond to ongoing adjustments over time.
Lasting relief for some
As for Stark, he’s down to 400mg of Sinemet a day and plays tennis and golf regularly. Today, he says, “most people can’t even tell I have Parkinson’s disease.”
Harriet Dekker, who had DBS 12 years ago, and Avi Shefet, who just recently underwent the procedure, echo Stark’s enthusiasm.
Before DBS, Dekker struggled with bradykinesia. But since then, she has made trips to New Zealand and Australia. More than a decade later, she says she believes DBS was a positive experience.
Shefet, for his part, says that he was unable to even turn over in bed prior to DBS. But post-surgery, he has already traveled to Europe and Israel. He’s even resumed his passion for sailing on the weekends.
“DBS gave me my life back,” he says. “I would do it again in a heartbeat.”
NOTE: The medical information contained in this article is for general information purposes only. It is crucial that care and treatment decisions related to Parkinson’s disease and any other medical condition be made in consultation with a physician or other qualified medical professional. Every patient is different, and responses to treatments like DBS may vary.