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Excessive postural sway and the risk of falls at different stages of Parkinson's disease

Authors

  • Anna Frenklach BA,

    1. Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
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  • Stephanie Louie MS,

    1. Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
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  • Mandy Miller Koop MS,

    1. Department of Mechanical Engineering, Stanford University, Stanford, California, USA
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  • Helen Bronte-Stewart MD, MSE

    Corresponding author
    1. Department of Neurology and Neurological Sciences, Stanford University, Stanford, California, USA
    2. Department of Neurosurgery, Stanford University, Stanford, California, USA
    • Department of Neurology and Neurological Sciences, Stanford University, 300 Pasteur Dr, Rm A343, Stanford, CA 94305-5327

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  • Potential conflict of interest: Nothing to report.

Abstract

Excessive postural sway may result in falls in Parkinson's disease (PD). We measured postural sway using the sensory organization test (SOT) of dynamic posturography in static (platform still) and dynamic (sway referenced platform) conditions with normal, no and inappropriate visual feedback in 102 subjects with PD, off medication. Twenty-five healthy subjects were used as age-matched controls. Eighteen very early stage PD subjects had never used dopaminergic medication. Postural sway was normal in those subjects in all conditions, but was abnormal in subjects with more advanced symptoms (UPDRS III > 20, P < 0.01). Postural sway increased with disease severity in all conditions except static, eyes closed (P < 0.0001). We developed the SOT Fall Severity Scale (SOTFSS) from the number of times postural sway was so large that the subject had to take a step (registered as a “fall”) and showed that falls mainly occurred in dynamic conditions, and were correlated with disease severity (P < 0.0001). In dynamic conditions the SOTFSS was correlated with the retropulsion score from the UPDRS III (N = 102, P < 0.0001) and with the subjects' self-reported fall frequency from the UPDRS II (N = 62, SOT5: P = 0.0419, SOT6: P = 0.0034). © 2008 Movement Disorder Society

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