The Effects of Postural Control Measures on Induced Slip Outcomes

Slips and falls are a major health concern in the United States. Injury incidence rates have increased in recent years and now the leading cause of non-fatal injuries and the third leading cause of fatal injuries in the U.S. are due to falls. During an unexpected slip, sensory information is used to elicit an appropriate recovery. Therefore, increased fall risk has been associated with declines in sensory system integrity. Previous research has suggested that decreased balance scores were associated with more hazardous slips yet measures of postural control between individuals who fall or recover after an induced slip have not been investigated. PURPOSE: To examine differences in slip detection using postural control measures between individuals who fall or recover after an induced slip. METHODS: One hundred participants were recruited for this study. Standing postural control measures were recorded under six different sensory conditions: eyes open, eyes closed, eyes open with sway referenced vision, eyes open with sway referenced support, eyes closed with sway referenced support, and eyes open with sway referenced vision and support. Variables of interest were sway velocity components and the root mean square of the center of pressure (CoP) in the medial-lateral and anterior-posterior directions. After postural control testing, participants completed testing involving a normal gait and an unexpected slip trial. The slip was classified as either a fall or a recovery. Once classified, standing postural control measures were examined between groups using independent t-tests. Additionally, prediction equations for slip outcome were created using a binary logistic regression model. RESULTS: The final analysis sample included 73 participants, with 48 trials classified as recoveries and 25 trials as falls. Postural sway when the proprioceptive (OR = 0.02, 95% CI: 0.01-1.34) and vestibular (OR = 0.60, 95% CI: 0.26-1.39) systems were relied on were negatively associated with odds of falling while visual system reliance resulted in a positive association (OR = 3.18, 95% CI: 0.887-11.445). CONCLUSIONS: The data suggests that visual sensory information may have a greater influence on dynamic stability and slip outcomes. Additionally, postural control measures may provide insight into task selection during recovery.