ST. PAUL, MN Electrical brain stimulation can reduce the problems Parkinson's patients develop after long-term use of the drug levodopa, the main treatment for Parkinson's, according to a study published in the November 27 issue of Neurology, the scientific journal of the American Academy of Neurology.
After years of use, levodopa becomes less effective, causing fluctuations in Parkinson's motor symptoms such as tremor and poor balance, called the "on/off" phenomenon.
Electrical brain stimulation increased the "on" motor function when medication was working by 29 percent, and improved the "off" motor function by 38 percent in the study. The process, also called deep brain stimulation, uses a surgical implant similar to a cardiac pacemaker to block brain signals that cause tremors and other signs of the disease.
The study examined 12 people who had stimulating electrodes implanted one to three years prior. They were monitored hourly for two days while taking their normal medications. One day the stimulators were turned on; one day they were turned off.
Six of the patients received stimulation in the globus pallidus interna nuclei of the brain; six were stimulated in the subthalamic nuclei. The patients were also able to complete a walking test 13 percent faster when the stimulator was on. And patients improved by 23 percent on a finger-tapping test, which measures bradykinesia, or the slowness in initiating movement that affects Parkinson's patients.
Other studies citing improvements from deep brain stimulation on levodopa-induced symptoms have been based on reports from patients, not on objective tests, according to study author and neurologist John Nutt, MD, of Oregon Health & Science University in Portland.
The study was also designed to help researchers determine how deep brain stimulation changes the body's response to levodopa. To that end, patients were studied for another two days, during which
Contact: Cheryl Alementi
American Academy of Neurology