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How cautious should we be when assessing apathy with the Unified Parkinson's Disease Rating Scale?

Authors

  • Lindsey Kirsch-Darrow MS,

    Corresponding author
    1. Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
    • Box 100165, Department of Clinical & Health Psychology, University of Florida, 101 South Newell Drive room 3151, Gainesville, FL 32610-0165
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  • Laura B. Zahodne MS,

    1. Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
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  • Chris Hass PhD,

    1. Department of Applied Physiology and Kinesiology, University of Florida, Gainesville, Florida, USA
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  • Ania Mikos PhD,

    1. Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
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  • Michael S. Okun MD,

    1. Department of Neurology, University of Florida, Gainesville, Florida, USA
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  • Hubert H. Fernandez MD,

    1. Department of Neurology, University of Florida, Gainesville, Florida, USA
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  • Dawn Bowers PhD

    1. Department of Clinical and Health Psychology, College of Public Health and Health Professions, University of Florida, Gainesville, Florida, USA
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  • Potential conflict of interest: None reported.

Abstract

Current practice often assesses apathy with a single item from the Unified Parkinson's Disease Rating Scale (UPDRS, item 4). Yet, the relationship between the UPDRS item 4 and the validated Apathy Scale (AS) is unknown. The purpose of this study was to evaluate the operating characteristics of UPDRS item 4 in relation to the AS. Three hundred and one patients with PD were administered the AS and the UPDRS. We compared the UPDRS item 4 to the standard AS classification of ≥14 as apathetic. A receiver operating characteristics (ROC) curve was obtained, and sensitivity, specificity, positive, and negative predictive power were calculated. The ROC curve showed area under the curve as 0.75. A cut-off of 1 had good sensitivity (81%) but poor specificity (53%; high false positive rate). A cut-off point of 2 had acceptable specificity (87%) but poor sensitivity (52%, high false negative rate). Continuing to increasing the cut-off point (e.g., 3, 4) continues to increase specificity at the expense of dramatically reducing sensitivity. These findings suggest the use of caution when screening for apathy with item 4 due to its poor sensitivity in relation to the AS. © 2009 Movement Disorder Society

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