Measurement Properties of a Virtually Administered 30-Second Chair Stand Test in People With Stroke.

Background and purpose: Muscle strength is important for functional independence after a stroke. Given the rise in telerehabilitation, there is a need to study the measurement properties of virtually administered performance-based measures. The purpose of this study was to assess the validity and responsiveness of a virtually administered 30-second chair stand test (30sCST-Virtual) in people with stroke.

Methods: Thirty-two hypotheses were generated about construct validity and responsiveness using several outcome measures (Stroke Impact Scale, strength domain [SIS-S], Timed Up and Go [TUG], Activities-Specific Balance Confidence Scale, Fugl-Meyer Lower Extremity Assessment, Functional Reach Test, and SIS cognition domain). Hypotheses were tested using Spearman's correlations. Scores on the 30sCST-Virtual were compared between higher- and lower-functioning participants using the modified Rankin Scale (mRS) and NIH Stroke Scale (NIHSS) with Wilcoxon rank-sum tests to assess known-groups validity.

Results: Sixty-seven participants (n = 19 female, 9.3 months post-stroke) with mild to moderate stroke were included. The 30sCST-Virtual demonstrated acceptable construct validity and responsiveness, as 14 (82%) and 12 (80%) hypotheses were confirmed, respectively. Its baseline scores were most highly correlated with the TUG (r = - 0.64) and change scores with the SIS-S (r = 0.35). The 30sCST-Virtual scores were also lower in those with lower function using the mRS (median difference [MD] = 4.0 repetitions, P < 0.001) and NIHSS (MD = 3.5 repetitions, P = 0.003), meeting our hypotheses for known-groups validity.

Discussion and conclusions: The 30sCST-Virtual demonstrated acceptable construct validity and responsiveness, as well as adequate known-groups validity. It was also moderately correlated with other measures of physical function, indicating that the 30sCST-Virtual may measure the construct of functional strength.

Video abstract available: For more insights from the authors (see the Video, Supplemental Digital Content available at http://links.lww.com/JNPT/A526).