Studies Evaluate the Reweighting of Parkinson Disease Assessment Tools for Improved Sensitivity and Efficiency

Reweighting the Movement Disorder Society–Unified Parkinson’s Disease Rating Scale (MDS-UPDRS) and other measures may provide greater sensitivity and responsiveness in assessing motor and functional decline in people with Parkinson disease (PD), according to the results of 2 studies presented at the American Academy of Neurology (AAN) 2025 Annual Meeting.

The first study included a group of 140 participants with confirmed early unmedicated PD from the Critical Path for Parkinson’s (CPP) dataset of the Critical Path Institute (Tucson, AZ). Researchers used partial least squares regression to select 8 items from the 39-item Parkinson’s Disease Questionnaire (PDQ-39) and 7 items from the MDS-UPDRS to develop the PARCOMS-Function composite scale, with the goal of optimizing sensitivity.

• PARCOMS-Function was 339.1% and 12.3% more responsive in detecting a change in disease progression compared with PDQ-39 and MDS-UPDRS Part II alone, respectively.
• Additionally, PARCOMS-Function retained only 30% of the items from PDQ-39 and MDRS-UPDRS Part II.

The second study included a group of 183 individuals from the CPP dataset and 430 individuals from the Parkinson’s Progression Markers Initiative (PPMI) dataset who were diagnosed with PD and were treatment naïve. Researchers used partial least squares regression to select 34 items from MDS-UPDRS Parts II and III to develop PARCOMS-Motor scales derived for each dataset.

• PARCOMS-Motor was 13.1% (CPP database) to 27.5% (PPMI database) more responsive than MDS-UPDRS parts II and III in detecting a change in disease progression.
• PARCOMS-Motor retained 34 (50%) of the items from MDS-UPDRS Parts II and III.
• Of the 34 items, 17 were retained in both the CPP- and PPMI-derived PARCOMS-Motor scales: 6 were retained only in the CPP version and 11 were retained only in the PPMI version.
• According to the study authors, inconsistencies between the CPP and PPMI dataset–derived scales potentially reflect differences in disease characteristics for participants in clinical trials vs natural history cohorts.

The findings of both studies demonstrate how the reweighting of assessment scale items may offer improved efficiency in clinical trials and greater sensitivity in detecting delays in disease progression when evaluating the effects of disease-modifying therapies (DMTs).

The authors of these 2 studies are affiliated with Biohaven Pharmaceuticals (New Haven, CT), Broadsheet HEOR (Vancouver, Canada), Clintrex (Sarasota, FL), the Pentara Corporation (Milcreek Utah), and the Johns Hopkins School of Medicine Department of Neurology.