Validity of the Instrumented Push and Release Test to Quantify Postural Responses in Persons With Multiple Sclerosis

Objective: To test the validity of wearable inertial sensors to provide objective measures of postural stepping responses to the push and release clinical test in people with multiple sclerosis. Design: Cross-sectional study. Setting: University medical center balance disorder laboratory. Participants: Total sample N=73; persons with multiple sclerosis (PwMS) n=52; healthy controls n=21. Main Outcome Measures: Stepping latency, time and number of steps required to reach stability, and initial step length were calculated using 3 inertial measurement units placed on participants' lumbar spine and feet. Results: Correlations between inertial sensor measures and measures obtained from the laboratory-based systems were moderate to strong and statistically significant for all variables: time to release (r=.992), latency (r=.655), time to stability (r=.847), time of first heel strike (r=.665), number of steps (r=.825), and first step length (r=.592). Compared with healthy controls, PwMS demonstrated a longer time to stability and required a larger number of steps to reach stability. Conclusions: The instrumented push and release test is a valid measure of postural responses in PwMS and could be used as a clinical outcome measures for patient care decisions or for clinical trials aimed at improving postural control in PwMS. (C) 2016 by the American Congress of Rehabilitation Medicine