Vol XXIV, May `06

One recent study that has garnered attention is the ELLDOPA study, conducted by the Parkinson's Study Group. This was a randomized, double-blind, placebo-controlled, parallel-group, multi-site clinical trial. Its purpose was to determine if Levodopa alters the natural course of Parkinson's disease. The main outcome variables of the trial were the change in severity as measured by the total Unified Parkinson's Disease Rating Scale (UPDRS).

Scores are slightly different between the treatment and placebo groups; they had about a two-point greater score on the UPDRS from the treating investigator than the primary rater, but they're more or less parallel to each other. And the same is true for the motor and activities of daily living component," said Stanley Fahn, MD, one of the study's investigators, at the World Parkinson Congress earlier this year.

There were a few adverse events, such as "a little more" headache in the 600-mg/day group and slightly increased muscle tone and dystonia. In the higher dosage groups, some nausea and vomiting were seen; and there was more leg pain in the placebo and low-dose groups. Dopaminergic adverse events included dyskinesias and wearing off in the 600-mg/day group. Freezing was more prevalent in the lower- than the higher-dose groups.

The study concluded that there was no evidence that Levodopa treatment is harmful or speeds PD progression. But neither did data prove that Levodopa is protective. Fahn stressed the need for further study in this area.

Many organizations agree with Fahn that more research is needed on this and other issues surrounding Parkinson's disease. The National Institutes of Health (NIH) is pumping millions of dollars into PD research. Among the opportunities is a call for grant applications for "Research on the Cognitive Sequelae of Parkinson's Disease." These applications should be for studies that "address the underlying neurobiological mechanisms associated with the cognitive impairment in Parkinson's disease, that address the development of clinical interventions and therapeutics for cognitive impairment in PD, or that promote improved clinical diagnosis or treatment of cognitive impairment in PD." Read about this and other PD research opportunities at www.ninds.nih.gov/funding/areas/neurodegeneration/index.htm.