Test-retest reliability and concurrent validity of gait variability and trunk stability dual task effect in people with chronic stroke

Dual-task walking is essential for community ambulation after stroke, yet its quantitative evaluation using variability-based metrics remains underexplored. To determine the test-retest reliability of gait variability and trunk stability dual-task effect (DTE), and explore their associations with clinically relevant assessments of balance and executive function. Twenty-nine individuals with chronic stroke (age = 63.6 ± 6.8 years, stroke duration = 6.1 ± 3.9 years) were included. Eight dual-task walking scenarios were performed: low and high complexity verbal fluency, serial subtraction, auditory Stroop and clock tasks. The DTE of gait parameters (stride length, gait variability and double support duration) and trunk stability (peak frontal velocity and range of motion) were calculated. Balance and executive function were assessed with the mini-balance evaluation system test (Mini-BESTest) and Wisconsin card sorting test (WCST), respectively. Intraclass correlation coefficients [ICC (2,1) ] and Pearson’s r were used to determine test-retest reliability and concurrent validity with clinical assessments, respectively. Test-retest reliability of stride length DTE was fair to excellent across all dual-task combinations (ICC = 0.53–0.81). High complexity serial-7-subtraction was the most reliable secondary cognitive task (ICC = 0.68). Significant correlations were observed between Mini-BESTest scores and cadence variability DTE ( r = 0.42–0.46) and stride time variability DTE ( r = 0.42–0.44). WCST scores were also correlated with cadence variability ( r = − 0.41) and stride time variability ( r = − 0.41 to − 0.45). Overall, high complexity serial subtractions produced the most consistent estimates for several gait DTE parameters, particularly variability-related outcomes. Among gait parameters, stride length DTE demonstrated consistently fair to excellent reliability and stride time variability DTE showed moderate association with clinical assessments of balance and executive function. These measures may have clinical utility for quantifying dual-task ability in people with chronic stroke.