Short-term repeatability of body sway during quiet standing in people with hemiparesis and in frail older adults.

OBJECTIVE To investigate short-term repeatability of a posturographic quiet standing test protocol in people with hemiparesis and in frail older adults. DESIGN Test-retest design, using 5 different quiet standing task conditions in which size and compliance of the support surface, visual influence, and cognitive demands were manipulated. Retest was performed after 15 minutes. SETTING Rehabilitation units and day care center. PARTICIPANTS Twenty-three people with stroke (mean age, 74.4y) and 16 frail older adults (mean age, 82.1y). INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES Repeatability of trunk acceleration root mean square by within-subject standard deviation, coefficient of variation, and intraclass correlation coefficients (ICCs). RESULTS The ICC(1,2) ranged from.13 to.75 for people with hemiparesis and from.73 to.92 for frail older adults when tested with their eyes open. The least demanding task condition gave the best repeatability. Standing with eyes closed resulted in very low ICC(1,2) in people with hemiparesis (.16) and in frail older adults (-.18). Interpretation of the results was similar for the other 2 reliability measures. CONCLUSIONS A mean of 2 repeated measures gave adequate repeatability for frail older adults but not for people with stroke when they were tested with their eyes open. This study showed the importance of establishing short-term repeatability relative to each clinical population in which such tests are used.

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