Metric attributes of the unified Parkinson's disease rating scale 3.0 battery: Part II, construct and content validity

Authors

  • Maria João Forjaz PhD,

    1. Neuroepidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain
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  • Pablo Martinez-Martin MD, PhD

    Corresponding author
    1. Neuroepidemiology Unit, National Center for Epidemiology, Carlos III Institute of Health, Madrid, Spain
    • Unidad de Neuroepidemiología, Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Calle Sinesio Delgado, 6, 28029 Madrid, Spain
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Abstract

This article is the second of a two-part series concerning the metric properties of the following three Parkinson's disease (PD) scales: modified Hoehn and Yahr staging (H&Y), Schwab and England (S&E), and Unified Parkinson's Disease Rating Scale (UPDRS) 3.0. Part II focuses on construct and content validity. To assess construct validity, a sample of 1,136 PD patients completed the above-mentioned PD scales. Correlation coefficients between measures of disability and dysfunction [S&E, UPDRS Activities of Daily Living (ADL), and UPDRS Motor Examination] were |r| = 0.69–0.77, indicating good convergent validity. Results showed that the S&E (F(5,945) = 193.47; P < 0.0001) and UPDRS subscales discriminated between modified H&Y stages (F(20,2784) = 25.28; P < 0.001). A panel of 12 to 13 international experts rated the relevance of the scales and items. This enabled the scales' content validity index to be calculated, which ranged from 41.7% (UPDRS Mentation) to 83.3% (UPDRS Motor Examination). In conclusion, while the modified H&Y, S&E, and UPDRS displayed satisfactory construct validity, the content validity of all scales except UPDRS Motor Examination failed to attain adequate standards. © 2006 Movement Disorder Society

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