Deep Brain Stimulation May Help Parkinson's

January 7, 2008) - Deep brain stimulation would appear to be a double-edged sword for people with advanced Parkinson's disease. (Read about "Parkinson's Disease") While it may help, it also comes with a cost, according to a study in the Journal of the American Medical Association. Patients with advanced Parkinson disease (PD) who received deep brain stimulation treatment had more improvement in movement skills and quality of life after six months than patients who received other medical therapy, but also had a higher risk of a serious adverse event.

Deep brain stimulation is a surgical treatment involving the implantation of electrodes that send electrical stimulation to specific parts of the brain (Read about "The Brain") to reduce involuntary movements and tremors. It is the surgical intervention of choice when PD motor (movement) complications are inadequately managed with medications, according to background information in the article. "However, recent reports highlighting unexpected behavioral effects of stimulation suggest that deep brain stimulation, while improving motor function, may have other less desirable consequences," the authors write. They add that there are few randomized trials comparing treatments, and most studies exclude older patients.

A total of 255 patients with PD were recruited for the study; 25 percent were age 70 years or older. A little less than half the group received bilateral deep brain stimulation. The rest received best medical therapy, which included management by movement disorder neurologists, who monitored medication use and nonpharmacological therapy (e.g., physical, occupational, and speech therapy).

The researchers found that at 6 months, deep brain stimulation patients gained an average of 4.6 hours per day of on time (the time of good symptom control or unimpeded motor function) without troubling dyskinesia (involuntary movements), while the average change for the best medical therapy group was 0 hours. Motor function improved significantly with deep brain stimulation compared with best medical therapy, with 71 percent of deep brain stimulation patients vs. 32 percent of best medical therapy patients experiencing clinically meaningful motor function improvements at 6 months, while 3 percent of deep brain stimulation patients and 21 percent of best medical therapy patients had clinically worsening scores.

However, the overall risk of experiencing a serious adverse event was 3.8 times higher in deep brain stimulation patients than in best medical therapy patients. Forty-nine deep brain stimulation patients (40 percent) experienced 82 serious adverse events. Fifteen best medical therapy patients (11 percent) experienced 19 serious adverse events. The most common serious adverse event was surgical site infection, with other serious adverse events including nervous system disorders (Read about "Nervous System"), psychiatric disorders, device-related complications and cardiac disorders. (Read about "The Heart & Cardiovascular System")