Measuring outcomes in Parkinson's disease: a multi-perspective concept mapping study

Purpose To identify and develop a conceptual map of prioritized areas and to determine their relative importance for outcome measurement in clinical Parkinson's disease (PD) trials, from the perspectives of health care professionals and people with PD. Method We used concept mapping, a qualitative/quantitative method consisting of three steps: item generation through focus groups (n = 27; 12 people with PD, 12 health care professionals, 3 researchers), item sorting and rating (n = 38; 19 people with PD, 19 health care professionals), and data analysis (multidimensional scaling, cluster analysis). Results Ninety-nine items and eight clusters were generated. Clusters representing Participation; Mobility and motor functioning; Cognitive and executive functioning; and Emotions were the most homogenous. Statements within clusters representing Energy and abilities; Autonomic dysfunctions; Sensory, speech and swallowing problems; and Neuropsychiatric symptoms also related to statements outside their respective clusters. Clusters rated most important were Participation and Mobility and motor functioning, and the highest rated items were quality of life, walking ability, and sleeping problems. Conclusion By the use of concept mapping, a multi-perspective conceptual map of prioritized aspects for the outcome measurement in PD was defined. These findings provide an initial conceptual basis toward improved outcome measurement priorities in clinical PD trials.