Deep Brain Stimulation May Stabilize Parkinson's Symptoms
Parkinson’s disease patients can generally expect their symptoms of shaking, stiffness, and loss of muscle control to progressively worsen over time. However, a deep brain stimulation device may help stabilize their symptoms, even after the device is turned off.
Deep brain stimulation may have lasting effects
Parkinson’s disease is a chronic, progressive movement disorder that affects approximately one million people in the United States. The cause is unknown and there is no cure, and so patients must rely on medications, surgery, and other treatment options to manage the symptoms. Deep brain stimulation (DBS) is proving to be an effective option.
Implantation of a deep brain stimulation device that has electrical leads is programmed remotely and, when used with medication, has been effective in controlling the motor symptoms of the disease. Patients have a handheld controller that allows them to block abnormal nerve signals that cause their uncontrollable muscle activity.
Use of the stimulation device does not eliminate the need for medications. However, it can reduce dosages and provide better movement control than drugs alone. Previous research showed that patients experienced improvements in motor function ranging from 27 to 72 percent within one year of having a deep brain stimulation device implanted.
Michele Tagliati, MD, director of the Movement Disorders Program at Cedars-Sinai Medical Center and a leading expert on deep brain stimulation, and his colleagues evaluated the impact of deep brain stimulation in Parkinson’s patients at various intervals: 21 patients at year one, 17 at year two, 14 at year three, 16 at year four, and nine at year five.
The researchers wondered what would happen if patients stopped taking their drugs and their stimulation device was turned off after five years of use. First they observed that when just the medications were stopped, patients with advanced Parkinson’s disease still enjoyed symptom relief from the implant, although there was a gradual deduction in benefit associated with the natural decline of the disease.
When patients discontinued both the drugs and the stimulation and their motor function was compared at yearly intervals with pre-treatment scores, the investigators found that “In these patients who were effectively treated with DBS stimulation, we found that motor symptoms remained remarkably stable over time. There was no significant progression.”
While this is a promising finding, experts are uncertain why deep brain stimulation appears to help stabilize Parkinson’s patients. Tagliati noted that DBS may stabilize motor progression, although some studies indicate the disease may naturally stabilize over time. Deep brain stimulation does not affect non-motor symptoms of the disease, including depression or dementia.
Deep brain stimulation is being used to treat a variety of other conditions as well. Recent studies have been investigating its use in the treatment of Tourette syndrome, severe obsessive-compulsive disorder, migraine, posttraumatic stress disorder, multiple sclerosis, and paralysis, among others.
Although most patients with Parkinson’s take medication, the drugs frequently fail to provide sufficient relief, especially over time, while other patients have especially unmanageable motor function symptoms. Deep brain stimulation may be an effective option for these individuals and help stabilize the disease in the process.
Parkinson’s Disease Foundation
Tagliati M et al. International Journal of Neuroscience 2010; 120(11): 717