Comparison of Psychometric Properties of Three Mobility Measures for Patients with Stroke

Abstract

BACKGROUND AND PURPOSE: This study compared the validity, responsiveness, and interrater reliability of 3 mobility measures in stroke patients from the acute stage up to 180 days after stroke onset. The 3 measures were the Rivermead Mobility Index (RMI), a modified RMI (MRMI), and the Mobility Subscale of the Stroke Rehabilitation Assessment of Movement ( STREAM). METHODS: The validity and responsiveness of the 3 mobility measures were prospectively examined by monitoring 57 stroke patients with the measures and the Barthel Index at 14, 30, 90, and 180 days after stroke onset . Two individual raters used the 3 measures to evaluate a different sample of 40 patients on 2 separate occasions to determine the interrater reliability. RESULTS: The Spearman rho between STREAM and MRMI was >or=BORDER=&quot;0&quot;>0.92; the intraclass correlation coefficient (ICC, a measure of agreement) between them was >or=0.89, indicating high concurrent validity of both measures. RMI showed a moderate to high relationship and agreement with STREAM and MRMI (rho >or=0.78, ICC>or=0.5) . Responsiveness of the 3 measures was high before 90 days after stroke onset (standardized response mean >or=0.83) and low at 90 to 180 days after stroke onset (0.2<or=standardized response mean<or=0.4). The score changes of the 3 measures at each stage were significant (P<or=0.05), except for RMI and MRMI at 90 to 180 days after stroke onset. The interrater agreement of the 3 measures was high (ICC>or=BORDER=&quot;0&quot;>0.92). CONCLUSIONS: All 3 measures examined showed acceptable levels of reliability, validity, and responsiveness in stroke patients . The psychometric characteristics of STREAM were slightly superior to those of the other 2 measures among our patients . We prefer and recommend STREAM for measuring mobility disability in stroke patients.