Test–retest reliability and relationship with clinical assessments of a depth sensor–based Fukuda Stepping Test in older adults

Aim: This study aimed to determine the test–retest reliability of the depth sensor–based Fukuda Stepping Test and its associations with clinical measures in older adults. Methods: A total of 86 older adults aged between 65 and 80 years were included in the study. Postural control and dynamic balance performance were evaluated using a modernized Fukuda Stepping Test performed with a Microsoft Kinect v2 depth sensor. Participants' balance, functional status, muscle strength, frailty, cognitive status, physical activity level, and quality of life were assessed using the Frail Scale, Berg Balance Scale, 360° Turn Test, Timed Up and Go Test, measurement of handgrip strength with a Jamar dynamometer, Five Times Sit-to-Stand Test, International Physical Activity Questionnaire–Short Form (IPAQ-SF), World Health Organization Quality of Life Scale for Older Adults (WHOQOL-OLD), Montreal Cognitive Assessment (MoCA), and Falls Efficacy Scale–International (FES-I). Test–retest reliability was examined in 23 participants and evaluated using the intraclass correlation coefficient (ICC). The relationships between Fukuda Stepping Test parameters and clinical measurements were analyzed using Spearman's rank correlation analysis (p < 0.05). Results: According to the test–retest analyses, moderate reliability was observed for test duration, anterior–posterior displacement, total planar displacement, head lateral flexion change, and head anterior–posterior displacement parameters (ICC = 0.58–0.68). Correlation analyses indicated that time- and displacement-based parameters showed low but statistically significant associations with the Timed Up and Go Test, Berg Balance Scale, and fear of falling. Head kinematic parameters demonstrated statistically significant relationships with cognitive status and physical activity level, while quality of life showed statistically significant associations with the sensory functioning and social participation subdomains (p < 0.05). Conclusion: The depth sensor–based Fukuda Stepping Test showed moderate reliability and meaningful associations with balance, cognition, physical activity, and quality of life, indicating its value as a complementary clinical assessment tool for older adults. Keywords: older adults, kinect, fukuda stepping test, balance, postural control