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I'm not a medical person or a researcher, but it seems to me this group is making some unfounded assumptions: 1) They assume there IS such a thing as Levodopa-induced dyskinesias. I don't believe there's any proof of this, just theory. 2) They assume reduced dosage of Levodopa following STN is responsible for fewer dyskinesias when patients are tested later with their stimulators off. In most DBS patients I know, even with the absence of stimulation, symptoms post-surgery never return to the severity of the symptoms pre-surgery. I've heard Dick's doctors theorize that the presence of the electrode in the brain, even with the stimulator turned off, acts like a mini-pallidotomy. The surgery Dick had, pallidal stimulation, doesn't usually result in a decrease in meds, yet the symptoms such as dystonia and dyskinesia didn't return full-force, even years later, when the stimulator was turned off. In cases where meds weren't reduced after surgery, doesn't that blow a hole in the "sensitization" theory? Brian Collins, do you have an opinion on this? Or Dr. Chris? Margie Swindler << Levodopa-induced dyskinesias in Parkinson's disease: is sensitization reversible? Levodopa-induced dyskinesias (LIDs) in patients with Parkinson's disease are considered to result from the severity of dopaminergic denervation in the striatum, which is an irrevocable phenomenon, and sensitization induced by long-term intermittent administration of levodopa. Taking advantage of the 64% reduction of levodopa treatment allowed in 12 Parkinson's disease patients by continuous high-frequency stimulation of the subthalamic nucleus, we evaluated the severity of parkinsonian motor disability and LIDs during 2 levodopa challenges performed before the surgical implantation of the stimulation electrodes and after 8.8 months of continuous bilateral subthalamic nucleus stimulation that was interrupted 2 hours before the levodopa test. Motor disability during the "off" and "on" drug periods was unchanged. The severity of LIDs during the "on" period and dystonia during the "off" period decreased by 54% and 62%, respectively. The reduced severity of LIDs in the absence of subthalamic nucleus stimulation demonstrates that the sensitization phenomenon resulting from long-term intermittent levodopa administration is partially reversible. >>