Study Rationale: Many different tests of memory and thinking are given to people with Parkinson’s disease (PD), but it is not clear how to use or combine these test scores to best detect early cognitive changes in PD. This study will use the many cognitive tests given as part of the Parkinson’s Progression Marker Initiative (PPMI) study to determine whether creating a single, combined score would be useful for finding early changes and predicting future worsening of cognition in PD.
Hypothesis: We think that combining a set of cognitive tests into a single composite score will provide a better method for detecting early changes in mental functioning in people with PD compared to looking at each test by itself or using a screening test for thinking.
Study Design: We will use the PPMI database of cognitive tests for people with PD who have been followed from disease onset out to 7 years. We will combine the scores on each test by averaging them to create a single composite score. We will then assess whether this composite score can differentiate people with PD from healthy controls, and whether it can be used to predict which individuals will experience a worsening in their cognitive abilities in the future.
Impact on Diagnosis/Treatment of Parkinson’s disease: If successful, this combined cognitive score could lead to a better understanding of the changes in thinking that occur over time in PD and could potentially be used in treatment studies to monitor cognitive decline or improvement.
Next Steps for Development: Once our results are published, researchers or health care providers might decide to use the same or a similar series of cognitive tests to create a composite score that can be used to guide treatment or further studies of PD.