(PhysOrg.com) -- Researchers at the University of Pennsylvania School of Medicine’s Udall Center for Parkinson’s Research have developed the first blood-based biomarker test to predict cognitive decline in Parkinson’s disease (PD). If results can be replicated and standardized in other Parkinson patients, by other investigators, the test could be a useful tool to use in selecting patients for the development of new drugs that can slow or prevent this complication of the disease.