Loaded and unloaded timed stair tests as tools for assessing advanced functional mobility in people with stroke

BACKGROUND: The Timed Stair Test (TST) was originally designed to measure advanced functional mobility in patients who have undergone a total hip replacement. Its psychometric properties have not been examined systematically in people with stroke. AIM: The aims of this study were to: 1) determine the intra-rater reliability of TSTunder loaded and unloaded condition; 2) identify the minimal detectable changes (MDCs) in TST completion times; 3) investigate the concurrent validity between TST completion times and stroke-specific outcome measures; and 4) determine the cut-off TSTcompletion time to differentiate the performance between people with stroke and healthy older adults. DESIGN: Cross-sectional study. SETTING: Auniversity-based rehabilitation center. POPULATION: Ninety-four people with stroke and 34 healthy older adults. METHODS: TSTs were conducted under loaded and unloaded conditions. Two trials of the TSTfor each of the two conditions were performed on the same day. The Fugl-Meyer Assessment of Lower Extremity (FMA-LE), lower-limb muscle strength test assessed by a hand held dynamometer, Berg Balance Scale (BBS), Limit of Stability (LOS) Test, Timed Up and Go (TUG) Test, and the Cantonese version of the Community Integration Measure (CIM) were also used to assess the subjects. RESULTS: Excellent intra-rater reliability was demonstrated for TST completion times under loaded (intraclass correlation coefficient [ICC2,1]=0.991) and unloaded (ICC2,1=0.985) conditions. The MDCs in TSTcompletion times were 6.55 seconds and 7.25 seconds under loaded and unloaded conditions, respectively. FMA-LE scores, mean strength of the affected-side dorsiflexors and plantar flexors, BBS scores, and LOSmovement velocity and maximum excursion scores demonstrated fair to excellent negative correlations with TSTcompletion times under both loaded (r=-0.314 to -0.786) and unloaded (r=-0.296 to -0.794) conditions. TUG results demonstrated good to excellent positive correlations with TSTcompletion times under both loaded (r=0.875, P<0.001) and unloaded (r=0.872, P<0.001) conditions. The TSTcompletion times of 26.3 seconds and 23.4 seconds under loaded and unloaded conditions, respectively, differentiated between people with stroke and healthy older adults.