Implanted stimulator for Parkinson's disease impairs cognitiv...( ed with that inhibition -- when stimula...),Health

Hershey says the STN -- where the electrodes are placed -- is very important in motor control and in Parkinson's disease, but it also has connections to cognitive areas of the brain. When a stimulator is turned on, it clearly changes the behavior and the firing pattern of neurons in the STN, but she says this study suggests that stimulation also may affect cognitive pathways in the brain.

In standard clinical practice, brain stimulators are set as high as they can go without causing motor side effects. But based on these findings, Hershey believes it might be possible to set stimulator parameters lower to provide motor benefit without affecting cognitive function.

"It's important to note that although the motor benefits of stimulation are very dramatic, the changes in cognitive function tend to be much less obvious," she says. "Those subtle effects fit with anecdotal reports from patients who sometimes complain that when their stimulators are on, they don't think quite as clearly. It's not such a dramatic change that everyone complains of it, but it could make things like paying bills or balancing a checkbook more difficult."

Hershey hopes to continue this research and test people at various stimulation levels to see whether it is possible to get motor benefits without causing declines in cognitive performance. She also would like to learn whether the location of the electrodes within the STN has any effect on cognitive declines, but technical limitations in imaging make that question difficult to study.

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Contact: Jim Dryden
drydenj@msnotes.wustl.edu
314-286-0110
Washington University School of Medicine
12-Nov-2003