A smartphone app-based application enabling remote assessments of standing balance during the COVID-19 pandemic and beyond

Assessments of postural control provide important insights into health We created a smartphone App-based assessment of standing posture—completed with the phone placed in the user’s pocket—to enable remote monitoring of function while minimizing the need for in-person assessment or contact We tested the reliability of App-derived postural sway metrics, as well as their sensitivity to age and task conditions Fifteen older and 15 younger adults completed two separate laboratory visits They followed multi-media instructions provided by the App to complete three 30-second trials of eyes-open (EO), eyes-closed (EC) and dual-task (DT) standing Sway data were recorded by the App and a force plate Participants also used the App to complete the assessment in their homes on three separate days Sway path length and root-mean-square were derived from the angular velocity and acceleration acquired from phone’s internal motion sensor, and from the center-of-pressure signal from force plate App-derived path length and root-mean-square of acceleration and angular velocity across conditions demonstrated moderate-to-excellent test-retest reliability (Intraclass Correlation Coefficients (ICCs)=0 69–0 97) for both younger and older adults Reliability was comparable to metrics derived from the force plate (ICCs=0 44–0 93) As expected, App-derived sway outcomes exhibited somewhat greater variability when tested across days at home (ICCs=0 14–0 79) All App-derived metrics were sensitive to age (F>43 8,p 31 8,p<0 001) in both laboratory and home settings, revealing that the smartphone App enabled reliable and sensitive assessment of standing posture in both healthy younger and older adults IEEE