The team will present its findings at 4 p.m. CT on Wed., Nov. 12, at the 33rd Annual Meeting of the Society for Neuroscience.
"It's clear that stimulation can provide a great deal of benefit to patients with Parkinson's disease," says principal investigator Tamara Hershey, Ph.D., assistant professor of psychiatry at the School of Medicine. "But when we looked at cognitive function, patients did better when their stimulators were turned off, although these effects were subtle."
Hershey and colleagues tested 24 patients with Parkinson's disease. All had electrodes surgically implanted into the STN, and when the electrodes were stimulated, all had improvements in tremors, stiffness, shaking and other motor symptoms that characterize Parkinson's disease.
The subjects were given two tests. In one, they looked at a computer screen and were asked to remember the spatial location where a dot appeared on the screen. They had to keep track of either one or two dots. When the task involved remembering the location of more than one dot, subjects performed better when their stimulators were off.
In a second task, subjects were required to press a button when a letter appeared on a computer screen and not to push the button when they saw a number. When subjects saw many letters and very few numbers, their natural tendency was to continue pressing the button whether their stimulator was on or off.
"When a number would appear, they had to try to inhibit the natural tendency to press the button," Hershey says. "Stimulation interfer
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Contact: Jim Dryden
drydenj@msnotes.wustl.edu
314-286-0110
Washington University School of Medicine
12-Nov-2003