Deep Brain Stimulation Lasts up to 5 years and Beyond

It’s not for all patients with Parkinson’s disease. It doesn’t improve mental function. But deep brain stimulation gives independent daily living back to most patients by improving muscle control.

It may not be for all patients with Parkinson’s disease. It will not improve overall mental function. But deep brain stimulation gives independent daily living back to most patients by improving the affected individuals motor control skills and overall co-ordination. How long does the effect of this relatively new procedure last? That’s still not clear. But the improvements continue for at least five years, find Paul Krack, MD, PhD, of Joseph Fourier University in Grenoble, France, and colleagues. They report five-year data on 49 patients in the Nov. 13 issue of The New England Journal of Medicine. The bottom line: Deep brain stimulation isn’t for all patients. It doesn’t work better than levodopa, one of medicine’s true miracle drugs and the standard of care for patients with Parkinson’s disease. It doesn’t prevent mental problems or stop the relentless progression of Parkinson’s disease. But it does offer long-lasting relief from the sometimes-disabling side effects of levodopa treatment. Krack and colleagues are among the first to use deep-brain stimulation — technically bilateral subthalamic stimulation — on Parkinson’s patients. The technique calls for dangerous surgery to implant electrodes in the motor cortex of the brain. The current report reflects the experience of the researchers’ first 49 patients. After five years, the patients’ motor function scores while off medication improved by 54%, and their daily living activity scores improved by 49%. Levodopa-induced movement problems and dose of levodopa medications decreased. There was no improvement in on-medication inability to move, speech, postural stability, or freezing of gait. “Five years after surgery, most patients were independent in their activities of daily living when assessed off medication,” Krack and colleagues write. “Before surgery, all patients had depended on a caregiver.” But there were serious downsides. Three patients developed dementia after three years. One patient committed suicide six months after the operation; another patient had a large brain hemorrhage. An editorial by Anthony E. Lang, MD, director of the University of Toronto Movement Disorders Unit, accompanies the Krack report. “Stimulation therapy should be considered for relatively young patients, before the development of a major disability that threatens their employment and their roles in their family and in society,” Lang notes. “Many elderly patients will not be good candidates for stimulation.” (Sources: Krack, P. The New England Journal of Medicine, Nov. 13, 2003; vol 349: pp 1925-1934. Lang, A.E. The New England Journal of Medicine, Nov. 13, 2003; vol 349: pp 1888-1891., WebMD Health News Dec 2003)