Neurology, the medical journal of the American Academy of Neurology, published a study this month which found that deep brain stimulation therapy is effective at providing long-lasting relief from certain symptoms of Parkinson’s disease, as well as the side effects of some common medications used to treat the progressive condition. Participants in the study also experienced continued improvement in their quality life from the treatment over the course of at least 15 years. Here’s what the latest research shows about the benefits of deep brain stimulation for people with Parkinson’s disease.
The Study
For the study, researchers set out to learn about how well people with Parkinson’s disease do over the long term after trying bilateral subthalamic nucleus deep brain stimulation, a treatment that was approved by the Food and Drug Administration (FDA) for treating advanced Parkinson’s disease about 20 years ago. People who get this therapy must undergo surgery to insert electrodes into the brain and an impulse generator battery (a device similar to a pacemaker) beneath the collarbone or in the abdomen. It then delivers electrical impulses to areas of the brain involved with motor function. Those who get this treatment can turn the device on and off with a controller. “The mechanism of action of deep brain stimulation is still an area of research. An oversimplified explanation is that it is acting like a noise-cancelation device,” says Jean-Philippe Langevin, MD, neurosurgeon and director of the Restorative Neurosurgery and Deep Brain Stimulation Program for the Pacific Neuroscience Institute at Providence Saint John’s Health Center in Santa Monica, California. He adds: “According to this model, the loss of dopamine cells from Parkinson’s disease leads to the introduction of interference between the different regions of the brain that control movement. This noise leads to the symptoms of Parkinson’s disease. Deep brain stimulation adds a monotonous and continuous signal that helps reduce the noise, thus making movement smoother.” The researchers looked at data on 51 people with Parkinson’s disease who had a deep brain stimulation device implanted at the Grenoble Alpes University in France. Participants had been diagnosed with Parkinson’s disease around the age of 40, on average, and had the device put in around age 51. The study followed up with the participants an average of 17 years after their surgery for the implant, and around 20% of the participants had had the device for 20 years or more, offering researchers a better understanding of the long-term impact of this treatment.
Findings on Medication Use and Motor Complications
The results showed that deep brain stimulation was effective at reducing motor complications from Parkinson’s disease for more than 15 years. The researchers also found that the therapy reduced the amount of time a person experienced dyskinesia by a whopping 75%. Dyskinesia is a side effect of a common Parkinson’s medication called levodopa that results in rapid, involuntary body movements, like twisting, squirming, and head bobbing. What’s more, participants spent about 59% less time in an “off state,” when medication stopped being as effective, and reduced their use of medications to manage dopamine levels by 51%. “This is striking and important because many drugs, including those used in Parkinson’s, have many side effects—especially at higher doses,” says Chad Bouton, MS, a professor and vice president of advanced engineering at The Feinstein Institutes for Medical Research at Northwell Health in New York, who has researched deep brain stimulation and bioelectronic medicine. He adds: “In the rapidly growing field known as bioelectronic medicine, technologies like deep brain stimulation are being developed that stimulate the nervous system with electrical impulses, instead of drugs. This often leads to dramatically reducing or eliminating side effects all together.”
Strength and Limitations of Deep Brain Stimulation
Even though participants still experienced progression of Parkinson’s disease over the course of the study, their quality of life continued to climb by an average of 14% from the time of their surgery to their follow-up around 15 years later. That finding illustrates both the strengths and the limitations of deep brain stimulation for Parkinson’s disease, experts say. “This study confirms that [certain people] with Parkinson’s disease will likely experience long-term benefits from deep brain stimulation. However, the study also revealed that deep brain stimulation is a symptomatic treatment, meaning that many features of the Parkinson’s disease will continue to progress, including walking, talking, and thinking issues,” says Michael S. Okun, MD, national medical advisor at the Parkinson’s Foundation, and chair of neurology and executive director at the Norman Fixel Institute for Neurological Diseases at University of Florida Health. Overall, experts say that these results help clarify the things people with Parkinson’s disease wonder about most when considering this treatment. “This study answers two critical questions that we often time get from our patients in clinic: How long will the effects of deep brain stimulation last? Does deep brain stimulation lose its effect over time?” says Dr. Langevin. “The authors of the study confirm our longstanding clinical observation that deep brain stimulation maintains its benefit over time.” It’s important to note that this study focused exclusively on deep brain stimulation targeting the subthalamic nucleus. The therapy can also target another part of the brain called the globus pallidus interna, but long-term results of deep brain stimulation on that area are not yet available.
Is Deep Brain Stimulation Right For You?
While deep brain stimulation is shown to offer long-term benefits, the treatment does come with some risks. According to the Parkinson’s Foundation, there is a 1% to 3% chance of developing an infection, cranial bleeding, stroke, or other complications from the treatment. Furthermore, deep brain stimulation might work better for some people than others. It might be an option worth considering if you’ve experienced symptoms of Parkinson’s for at least five years, are struggling with side effects of Parkinson’s medications, or your symptoms make it difficult to perform everyday activities, among other factors. “The decision for or against deep brain stimulation should be made by having the potential candidate evaluated by a multidisciplinary team who can together construct a risk-benefit profile for a potential candidate,” explains Dr. Okun. “The team commonly is made up of a neurologist, a neurosurgeon, a neuropsychologist, a psychiatrist, and rehabilitation specialists.” Talk with a neurologist if you have Parkinson’s disease and you’re interested in exploring deep brain stimulation. While deep brain stimulation has shown promising results for people with Parkinson’s disease, there are some risks involved. Experts say that you should work with a multidisciplinary team of medical professionals to determine if the potential benefits of this treatment outweigh the risks involved.
