Comparative analysis of gait domains in middle-aged and older adults under single- and dual-task conditions

Background: Dual-task gaits are linked to falls in older individuals, but their underlying structure is unknown compared to single-task gaits. We employed principal component analysis (PCA) to discover independent domains underlying single- and dual-task gaits in cognitively healthy community-dwelling people over 45. Methods: One hundred eighty-nine independent individuals (aged 45-80) completed health surveys, physical and cognitive tests, and walking evaluations under single-task, motor dual-task, and cognitive dual-task conditions. We applied PCA to 17 spatiotemporal gait parameters to identify independent domains for each gait. Logistic regression analyses were conducted to determine demographic, physical, and cognitive characteristics associated with domain scores. Results: The results revealed six independent domains consistent across all three gait types: rhythm, variability, phase, pace, base of support (BOS), and asymmetry. These domains accounted for 77.2-83.8 % of the overall gait variance. Rhythm, variability, and phase were the top three domains for all three gait types. Pace was the fourth domain for single- and motor dual-task gaits, while asymmetry held this position for the cognitive dual-task gait. In all three gaits, male sex and heavier weight were associated with greater BOS scores. Taller height and shorter five-times-sit-to-stand test (5XSST) time were associated with greater pace scores, while heavier weight was additionally linked to greater phase scores (p < 0.05). Notably, greater variability domain scores in the cognitive dual-task gait were uniquely associated with poorer executive function, balance, and shorter 5XSST time (p < 0.05). Significance: PCA results revealed consistent gait domains across single-, dual-, and cognitive dual-task conditions in older adults. These findings support the feasibility of using standardized, streamlined assessments focusing on these core domains in geriatric gait assessments. Findings of the unique cognitive dual-task gait characteristics highlight the importance of assessing gait variability and asymmetry of this gait for fall risk screening and prevention interventions.