Subject-investigator reproducibility of the Unified Parkinson's Disease Rating Scale

Abstract

Objective: To evaluate the subject-investigator agreement on the Unified Parkinson's Disease Rating Scale (UPDRS) subsections I and II.

Methods: Subject-investigator agreement was estimated at baseline and endpoint by Kappa statistics for individual items and concordance correlations for subscale totals using data from two NIH Exploratory Trials in Parkinson's Disease studies.

Results: All but two questions had moderate subject-investigator agreement at baseline and endpoint. Participants consistently rated their disease activity worse that investigators.

Conclusion: UPDRS self-administration produces similar results to investigator-administration. Although slightly elevated, UPDRS self-administration can be accommodated in a clinical trial setting.