Clinical Outcome Assessments in Parkinson's Disease: A Scoping Review of Current Rating Scales and Future Needs

Clinical outcome assessments (COAs) are essential for evaluating symptom severity, treatment response, and disease progression in Parkinson's disease (PD). As clinical knowledge evolves, it is necessary to revisit the recommendation status on the COAs to ensure their continued relevance and validity.

To provide an updated overview of existing MDS-recommended COAs in PD and to identify specific constructs requiring revision or further validation to inform current clinical practice and research.

The Scientific Evaluation Committee of the Movement Disorder Society COA program commissioned a position paper on the current state of COAs' recommendations. A panel of experts conducted a two-step review: first, extracting data from previous MDS publications of rating scales on COAs appraisals using a standardized template; second, conducting a scoping review up to April 2025 to identify new COAs or updated validation data on motor and non-motor constructs in PD. All study designs were considered.

Of the 19 PD constructs identified, anxiety, apathy, anhedonia, dysautonomia, and pain had significant developments, including new COA development and further validation, making them priorities for revision. Recent reviews show that constructs like medication adherence and psychosis were sufficiently addressed.

This review identifies key symptom areas where COA critique and recommendations need to be updated to reflect advances in the field and improve assessment accuracy in clinical and research settings.