Metric attributes of the unified Parkinson's disease rating scale 3.0 battery: Part I, feasibility, scaling assumptions, reliability, and precision

This article sought to assess the feasibility, scaling assumptions, reliability, precision, and factor analysis of the three most widely used rating scales in Parkinson's disease (PD): modified Hoehn and Yahr (HY), Schwab and England (SE), and Unified Parkinson's Disease Rating Scale (UPDRS). A multicenter sample of 1,136 PD patients was assessed. The percentage of missing data was 8% for SE, HY, and UPDRS mentation, and almost negligible ( 90%). Internal consistency coefficients for the UPDRS scales ranged from 0.79 (mentation) to 0.92 (activities of daily living and motor). Factor structure of the UPDRS mentation, activities of daily living, and complications subscales was replicated. As a whole, the HY, SE, and UPDRS are acceptable, consistent, and potentially sensitive rating scales. © 2006 Movement Disorder Society