Assuring interrater reliability for the UPDRS motor section: utility of the UPDRS teaching tape

We assessed rates of successful certification on the motor section of the Unified Parkinson's Disease Rating Scale (UPDRSm) after training with the UPDRS Teaching Tape. The most frequently used clinical scale for PD is the UPDRS, and most clinical trials rely on the motor examination as the primary outcome measure. Whereas the Movement Disorder Society's UPDRS Teaching Tape has been used widely as a training format, outcome data are lacking. We examined data sets from four multicenter studies that required raters to pass the certification exercise of the UPDRS Teaching Tape. Raters viewed the Teaching Tape showing examples of all rating levels for all items (38 minutes), and then took the certification exercise, rating 4 subjects with PD (20 minutes). Certification required scores on all 4 subjects that fit within the 95% confidence interval range established by three experts. We calculated the numbers of raters successfully certified after one or more rating attempts. Only one-half of 226 raters that participated successfully completed certification on their first attempt, but all completed by the third attempt. North American raters scored better than Europeans raters. The most difficult case to rate was the subject with the least impairment. Standardized methods for training UPDRSm application are essential to ensure that raters use the scale uniformly. Raters have the greatest difficulty with the mildest impairment, making training especially important to studies of early PD.