Brain Stimulation Improves Parkinson's Signs, But With Some Risk

Adding deep brain stimulation to medical therapy for Parkinson's disease improved symptoms and physical function, though the required surgery had adverse effects for nearly 20 percent of patients, including one death.

Adding deep brain stimulation to medical therapy for Parkinson's disease improved symptoms and physical function, though the required surgery had adverse effects for nearly 20 percent of patients, including one death.
After a year, "clinically meaningful" and statistically significant improvements in mobility and activities of daily living were seen in 183 patients who received the deep brain stimulation device in addition to medical therapy, compared with the same amount who had only medical therapy in an open-label trial, reported Dr. Adrian Williams of Queen Elizabeth Hospital in Birmingham, England, and colleagues.
"But surgery is not without risk and targeting of patients most likely to benefit might be warranted," the researchers wrote online in Lancet Neurology.
They also suggested the risk-benefit balance in deep brain stimulation could improve even more with better understanding of its therapeutic mechanism and optimizing the details of electrode placement and other parameters.

Deep brain stimulation involves implanting a device similar to a cardiac pacemaker in the chest, with electrodes running up the neck, through the skull, and into certain locations in the brain. Delivery of small currents to these regions has been shown to improve some symptoms of Parkinson's disease, although the surgery is necessarily invasive and difficult.

In this trial, Williams and colleagues randomized 366 patients with advanced Parkinson's disease from 2000 to 2006 to receive "best medical therapy" with or without deep brain stimulation.

Patients had baseline scores on the 39-item Parkinson's Disease Questionnaire (PDQ-39), the study's primary outcome measure, of about 38. Average duration of symptoms was about 11 years.

After one year in the study, average PDQ-39 scores across all domains were 32.5 in the surgery group compared with 38.7 in the patients receiving only medical therapy, for a mean difference of 5.6 points.

However, of the eight domains included in the PDQ-39, a significant advantage for surgery was seen for only four: