Test-Retest Reliability and Minimal Detectable Change for the 10-Meter Walk Test in Older Adults With Parkinson's disease

Background and Purpose: Measurement of gait performance in individuals with Parkinson's disease (PD) can be challenging because of the daily fluctuations in performance and the progressive nature of the condition. The 10-Meter Walk Test (10MWT) is commonly used to measure gait speed of individuals with gait limitations. Existing research on the 10MWT in individuals with PD controls for many variables inherent to this condition, rendering the results of this test in settings where these variables are not controlled questionable. The purpose of this study was to estimate under commonly encountered clinical conditions the test-retest reliability and the minimal detectable change (MDC) of gait speed and step frequency determined during the 10MWT in individuals with PD. Methods: The 10MWT was administered by 2 testers, on 35 participants, across 2 sessions, separated by 5 to 14 days. Gait speed was measured using a hand-held stopwatch, and step frequency was assessed through visual observation. Test-retest reliability was calculated using the intraclass correlation coefficient (ICC) and the MDC was calculated using the standard error of measurement (SEM). Results and Discussion: Comfortable and fast gait speeds demonstrated excellent reliability between sessions (ICC = 0.92 and 0.96, respectively). The corresponding MDCs were 0.22 and 0.23 m/s, respectively. The test-retest reliability for step frequency was moderate for comfortable gait speed and good for fast gait speeds (ICC = 0.73 and 0.82, respectively). The corresponding MDCs were 15.1 and 17.4 steps per minute for comfortable and fast step frequency, respectively. Conclusions: Under both comfortable and fast conditions, measurements of gait speed and step frequency during the 10MWT are reliable between sessions in individuals with PD.