For people with advanced Parkinson’s disease, electrical stimulation through an electrode implanted in one side of the brain produces long-lasting improvements in movement difficulties on both sides of the body, a new study shows.

“If you can get nice benefit with unilateral deep brain stimulation, why not do that and minimize the risk” associated with more extensive surgery, Dr. Jay L. Alberts said in an interview with AMN Health.

Then if the disease should progress, he said, the opposite side will still be available for implantation of a second deep brain stimulation device.

Currently, most surgeons perform bilateral procedures, Alberts explained.

Alberts, with the Atlanta VA Rehabilitation and Research Center, and his associates tested the manual dexterity of both hands of patients with advanced Parkinson’s disease who were given unilateral deep brain stimulation devices. The devices were implanted on the opposite side to the dominant hand, and were in place for 11 to 55 months.

The subjects all exhibited improvements in scores on a Parkinson’s disease rating scale when the electrodes were turned on, team reports in the journal Motor Control. The patients also displayed better reaching consistency and grip force, as well as decreased movement times.

The devices were also tested in two different regions of the brain - known as the subthalamic nucleus and the globus pallidus. The procedure normally involves subthalamic stimulation, but the researchers found no evidence that one site was better than the other.

This is important, Alberts said, because “data suggest that stimulating the subthalamic nucleus may increase certain neuropsychological problems, such as depression and working memory deficits.” Hence, implantation in this area should be avoided in patients with depression or mild cognitive impairment.

“We hope this study opens up the possibility of deep brain stimulation in the globus pallidus for other patients who might not ordinarily qualify for stimulation of the subthalamic nucleus,” he said.

SOURCE: Motor Control, October 2004.