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 ICC1.2 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 ICC1.2 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. (C) 2004 by the American Congress of Rehabilitation Medicine and the American Academy of Physical Medicine and Rehabilitation.