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Logo for the Journal of Rehab R&D
Volume 41 Number 5, September/October 2004
Pages 713 — 720

Measures of postural stability

Hans Chaudhry, PhD; Thomas Findley, MD, PhD; Karen S. Quigley, PhD; Bruce Bukiet, PhD; Zhiming Ji, PhD; Tiffany Sims, MS; Miriam Maney, MS

War-Related Illness and Injury Study Center, Department of Veterans Affairs Medical Center, East Orange, NJ;
Departments of Biomedical Engineering and Mechanical Engineering, New Jersey Institute of Technology, Newark, NJ; Department of Psychiatry, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, Newark, NJ; Department of Mathematical Sciences and Center of Applied Mathematics and Statistics, New Jersey Institute
of Technology, Newark, NJ
Abstract — Dynamic posturography has become an important tool for understanding standing balance in clinical settings. A key test in the NeuroCom International (Clackamas, Oregon) dynamic posturography system, the Sensory Organization Test (SOT), provides information about the integration of multiple components of balance. The SOT test leads to an outcome measure called the "equilibrium score" (ES), which reflects the overall coordination of the visual, proprioceptive, and vestibular systems for maintaining standing posture. Researchers, therapists, and physicians often use the ES from the SOT as a clinically relevant measure of standing balance. We discuss here the formula used for evaluating the ES and propose an additional measure of postural stability, called the Postural Stability Index (PSI), that accounts for shear force and individual anthropomorphic measures. We propose that this new measure provides a clinically important adjunct to the current SOT and can be calculated from data already collected by the NeuroCom forceplate during the SOT.
Key words: dynamic posturography, equilibrium, mathematical model, medically unexplained symptoms, posture, standing balance, veterans.

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