Deep Brain Stimulation for Parkinson's Disease

Treatment

Unlike previous surgeries for PD, DBS involves minimal permanent surgical changes to the brain. Instead, the procedure uses electrical stimulation to regulate electrical signals in neural circuits to and from identified areas in the brain to improve PD symptoms. Thus, if DBS causes unwanted side effects or newer, more promising treatments develop in the future, the implantable pulse generator can be removed, and the DBS procedure can be halted. Also, stimulation from the IPG is easily adjustable—without further surgery—if the person’s condition changes. Some people describe the pulse generator adjustments as "programming."

Prognosis

Although most individuals still need to take medication after undergoing DBS, many people with Parkinson’s disease experience considerable reduction of their motor symptoms and are able to reduce their medications. The amount of reduction varies but can be considerably reduced in most individuals, and can lead to a significant improvement in side effects such as dyskinesias (involuntary movements caused by long-term use of levodopa). In some cases, the stimulation itself can suppress dyskinesias without a reduction in medication.  DBS does not improve cognitive symptoms in PD and indeed may worsen them, so it is not generally used if there are signs of dementia.  DBS changes the brain firing pattern but does not slow the progression of the neurodegeneration.

Research

The National Institute of Neurological Disorders and Stroke (NINDS), a part of the National institutes of Health (NIH), supports research on DBS to determine its safety, reliability, and effectiveness as a treatment for PD. NINDS supported research on brain circuitry was critical to the development of DBS.Researchers are continuing to study DBS and to develop ways of improving it. A two-part study funded by the NINDS and the Department of Veterans Affairs first compared bilateral DBS to best medical therapy, including medication adjustment and physical therapy. Bilateral DBS showed overall superiority to best medical therapy at improving motor symptoms and quality of life. The second part of the study, involving nearly 300 patients, compared subthalamic nucleus (STN) DBS to globus pallidus interna (GPI) DBS.  The two groups reported similar improvements in motor control and quality of life in scores on the Unified Parkinson’s Disease Rating Scale. On a variety of neuropsychological tests, there were no significant differences between the two groups. However, the STN DBS group experienced a greater decline on a test of visuomotor processing speed, which measures how quickly someone thinks and acts on information. Also, the STN DBS group had slight worsening on a standard assessment of depression, while the GPI DBS group had slight improvement on the same test. The importance of these two differences is not clear, and will be scrutinized in follow-up research.In addition, NINDS-supported researchers are developing and testing improved implantable pulse generators, and conducting studies to better understand the therapeutic effect of neurostimulation on neural circuitry and brain regions affected in PD. For more information about current studies on brain stimulation and Parkinson’s disease, see www.clinicaltrials.gov and search for “deep brain stimulation AND Parkinson AND NINDS.” For information about NINDS-and NIH-supported research studies in this area, see the NIH RePORTER (Research Portfolio Online Reporting Tools) at http://projectreporter.nih.gov and search for “deep brain stimulation AND Parkinson.”The Brain Initiative for Advancing Innovative Neurotechnologies (BRAIN) initiative, announced in 2013, offers unprecedented opportunities to unlock the mysteries of the brain and accelerate the development of research and technologies to treat disorders such as Parkinson’s disease.  For more information about the BRAIN initiative, see www.nih.gov/science/brain.

Organizations