Rating scale for psychogenic movement disorders: Scale development and clinimetric testing

Authors

  • Vanessa K. Hinson MD, PhD,

    Corresponding author
    1. Department of Neurosciences, Medical University of South Carolina, Charleston, South Carolina, USA
    • Medical University of South Carolina, Charleston Memorial Hospital, 326 Calhoun Street, Suite 308, Charleston, SC 29425
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  • Esther Cubo MD,

    1. Sanatorio del Rosario, Clinica de la Zarzuela, Department of Neurology, Madrid, Spain
    2. Department of Neurological Sciences, Rush University/Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA
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  • Cynthia L. Comella MD,

    1. Department of Neurological Sciences, Rush University/Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA
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  • Christopher G. Goetz MD,

    1. Department of Neurological Sciences, Rush University/Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA
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  • Sue Leurgans PhD

    1. Department of Neurological Sciences, Rush University/Rush-Presbyterian-St. Luke's Medical Center, Chicago, Illinois, USA
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Abstract

We developed and tested the clinimetric properties of a scale for psychogenic movement disorders (PMDs). PMDs are disabling but lack any generally accepted treatment strategies. To develop treatments, means of assessing disease severity must be provided. No scale to assess PMDs existed. The PMD scale developed here rates 10 phenomena (rest tremor, action tremor, dystonia, chorea, bradykinesia, myoclonus, tics, athetosis, ballism, cerebellar incoordination), 2 functions (gait, speech), and 14 body regions. To study interrater agreement, three movement disorder neurologists independently rated 88 videotapes of PMD patients. Data analysis was performed using a kappa coefficient of agreement, Kendall's coefficient of concordance, Spearman correlations, and intraclass correlation coefficients. Validity and scale responsiveness were tested as well. All phenomena and speech and gait dysfunction occurred in the patient sample. A wide range of affected body regions, severity, and incapacitation was captured. Ratings showed excellent interrater reliability for presence or absence of each phenomenon (κ range, 0.63 to 0.86). Kendall's concordance coefficients for phenomenology, function, and total PMD scores were 0.92, 0.93, and 0.91. Spearman correlations between raters ranged from 0.86 to 0.90. The scale was responsive to changes that occurred as a result of a neuropsychiatric intervention. The PMD scale adequately captures the complex movements of PMDs and can be used to assess PMDs and test the efficacy of intervention strategies. © 2005 Movement Disorder Society

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