This study analyzed the Parkinson’s Progression Markers Initiative MDS-UPDRS data Parts II and III in subjects with confirmed PD naïve to DT. Patients were censored from the analysis once DT was initiated. The sensitivity of individual items to disease progression was assessed using partial least square regression. Selected items were weighted using the model coefficients and summed to create the CS. CS responsiveness to change was assessed using a 1-year mean-to-standard-deviation ratio (MSDR).

CS were generated for untreated subjects (n=428) across items from Parts II and III individually, and as a combined motor composite score (MCS). The three most responsive items (with their combined weights) were: turning in bed, getting out of bed/car/chair, and tremor (45%) for Part II, and leg agility (left) and rest tremor amplitude – left and right (34%) for Part III. The MSDRs increased from 0.5431 to 0.5647, and 0.6341 to 0.7040, which increases power 3% and 8%, respectively.   Items from Part II and III contributed to 37.4% and 62.6% of the weighed MCS. Similar items were retained in the MCS as in the individual CSs, and the MSDR increased from 0.7615 to 0.8591, increasing power 8%.