Reliability and minimal detectable change of gait variables in community-dwelling and hospitalized older fallers

Abstract

PurposeGait variables may constitute surrogate outcomes for fall risk. Their reliability in a specific population of older fallers has not been fully established, which limits their research and clinical applications. This study aimed to determine test–retest reliability and minimal detectable change (MDC) values for selected fall-related gait variables in older adults with a recent fall history. MethodsCommunity-dwelling (n=30) and hospitalized (n=30) fallers aged≥65 years were assessed twice using an instrumented pressure-sensitive walkway, under single- and dual-task gait conditions. Intraclass correlation coefficient (ICC(2,1)), standard error of measurement (SEM; SEM%) and MDC at 95% confidence level (MDC95; MDC95%), were used as reliability estimates. ResultsThe ICC(2,1) for gait velocity was greater than 0.84 across all gait conditions and groups; SEM% and MDC95% did not exceed 6.5% and 18.1%, respectively. Gait variability measures returned lower ICC(2,1) (range 0.18–0.79), and markedly higher SEM% (16.3–31.9%) and MDC95% (45.3–88.3%). Overall, hospitalized fallers exhibited larger SEM and MDC95 values for variability measures compared to community-dwellers in all gait conditions, while larger values were found for all variables while dual-tasking compared to single-tasking in both groups. ConclusionsGait velocity was found to be highly reliable and likely to be sensitive to change over repeated sessions in community-dwelling and hospitalized older fallers, both under single- and dual-task conditions. Gait variability measures showed lower reliability, irrespective of gait condition or group, displaying consistently larger measurement error, particularly under dual-task conditions. Clinicians should consider MDC95 values before using gait variability variables as evaluative outcome measures at patient level.