Cognitive-motor interference in walking after stroke : test–retest reliability and validity of dual-task walking assessments

Abstract

Objective: To explore the reliability and validity of a series of dual-task mobility assessments among individuals post-stroke. Design: Observational study with repeated measures. Setting: University laboratory. Participants: Thirty community-dwelling individuals with chronic stroke. Interventions: Not applicable. Main Measures: Each of the two mobility tasks (1-minute level-ground walking with and without obstacle-negotiation) was performed concurrently with each of the eight cognitive tasks (auditory Stroop test, serial subtraction, shopping list recall and category naming at two difficulty levels). Walking distance and obstacle hitting rate (OHR) indicated dual-task mobility performance. Number of correct responses (NCR) indicated cognitive performance. Reaction time was additionally measured for the auditory Stroop test. Construct validity was examined by correlations between the dual-task assessments. The dual-task assessments were repeated within 7–14 days for test–retest reliability. Results: Excellent test–retest reliability in walking distance and OHR was found (intraclass correlation coefficient, ICC(3,1) = 0.891–0.984, P < 0.05). Moderate to excellent reliability was found in NCR and reaction time (ICC(3,1) = 0.480–0.911, P < 0.01). Correlations between walking distance were excellent (rs = 0.840–0.985, P < 0.01). Correlations of NCR and reaction time between low- and high-level cognitive tasks were mostly moderate to excellent (rs = 0.515–0.793, P < 0.01). Generally no significant correlations were found in NCR between the dual-task assessments with different cognitive domains. Conclusion: The dual-task walking assessments are reliable and valid for evaluating cognitive-motor interference in community-dwelling individuals post-stroke. The lack of correlations between the tasks of different cognitive domains indicates the need of using different cognitive domains in dual-task walking assessment post-stroke.