Michael Frank did what any thoughtful person would. He asked a
patient suffering from Parkinson's disease if he would like to
sit in a more comfortable chair across the room. However,
instead of taking a moment to think about it, the patient
immediately stood up and tried to get to the chair -- completely
ignoring the fact he was unable to walk. "He couldn't walk
without a wheelchair, and I had to help to prevent him from
falling down," says Frank, an assistant professor of psychology
at the University of Arizona at Tucson. "He saw the chair,
thought it was a good idea, and got up to walk toward it without
really thinking about his condition." This kind of impulsive
behavior may be a side effect of deep brain stimulation that is
used to treat Parkinson's disease. Deep brain stimulation helps
some patients control debilitating tremors, but new research
suggests it may also impair decision making. In a new study to
be published in the journal Science, researchers found that when
Parkinson's patients received br