A study was conducted to assess how a new metric, average in-home gait speed (AIGS), measured using a low-cost, environmentally mounted, continuous monitoring system, compares to a set of traditional physical performance instruments used for mobility and fall risk assessment of elderly adults. Sixteen participants were recruited from a local independent living facility. In addition to having their gait monitored continuously in their home for one-two years, the participants completed a monthly clinical assessment consisting of a set of traditional assessment instruments: Habitual Gait Speed, Timed-Up-and-Go (TUG), Short Physical Performance Battery, Berg Balance Scale – short form, and Multidirectional Reach Test. A methodology is developed to assess which of these instruments may work well with the largest subset of older adults, offers the best sensitivity for detecting changes in an individual over time, and most reliably captures the functional ability level of an individual. Using the ability of an instrument to predict how an individual would score on all the instruments as a metric, AIGS performs best, having better prediction power than the traditional instruments. AIGS also displays the best agreement between observed and filtered values, indicating it has the lowest test-retest variability of the instruments. AIGS, measured continuously, during normal everyday activity, represents a significant shift in assessment methodology as compared to traditional physical performance measures. Continuous, in-home data may provide a more accurate and precise picture of physical function of older adults, revolutionizing mobility and fall risk assessment.
Stone, E., Skubic, M., Rantz, M.J., Abbott, C., & Miller, S. (2015). Average in-home gait speed: Investigation of a new metric for mobility and fall risk assessment of elders. Gait & Posture, 41, 57-62.*