Limb Restoration Rehabilitation
Clinical Practice (assessment, diagnosis, treatment, knowledge translation/EBP, implementation science, program development)
Practice effects in performance-based balance test administered to lower limb prosthesis users may limit their discriminative, evaluative, and predictive applications. This presentation will describe the magnitude of practice effects observed among several contemporary performance-based balance tests administered lower limb prosthesis users, and explore their potential implications for clinical assessment of balance ability and fall risk.
Characterize practice-effects and their clinical significance in two performance-based clinical balance tests administered to lower limb prosthesis (LLP) users.
Design : Cross-sectional
Setting : Research laboratory and prosthetics clinic.
Participants (or Animals, Specimens, Cadavers) : Convenience sample of 40 established unilateral LLP users.
Interventions : Not applicable
Main Outcome Measure(s):
Practice-effects in the Timed Up and Go (TUG) and Four Square Step Test (FSST) were quantified as significant changes (p‹0.01) in the slope of participants’ cumulative record over 10 consecutive trials. The clinical significance of any practice-effects were assessed by determining if difference between traditional scoring (i.e., best of trials 1 and 2) and the mean of later stable performance exceeded the standard error of measurement (SEM) of each test, and if test scores based on the mean of later stable performance re-classified participants’ fall risk (i.e., above/below fall-risk cutoffs).
Results : Significant changes in performance were observed until the fifth trial of the FSST and TUG in 15/20 and 14/20 of participants, respectively. Stable performance (i.e., beyond the fifth trial) was significantly better (i.e., lower time), p‹.0015, than during earlier trials (i.e., trials 1 and 2). Differences in scores between the best of trials 1 and 2, and the mean of later stable performance exceeded the SEM of the FSST and TUG in 10/20 and 8/20 participants, respectively. When tests were re-scored using the mean of later stable performance, 6/20 and 5/20 participants were re-classified from fallers to non-fallers, or vice versa, on the FSST and TUG respectively.
Traditional FSST and TUG administration and scoring procedures do not account for practice-effects among LLP users, potentially overlooking important differences in balance. Further research developing procedures that address practice-effects, and improve the accuracy of balance assessments in LLP users is therefore needed.