The effects of route previewing on adaptive gait and gaze behaviour under cognitive dual-task conditions in older adults

Background: Safely walking through complex environments requires the use of visual information to plan and regulate steps, while managing competing cognitive demands. Age-related changes in visual control of gait and executive function may contribute to unsafe stepping behaviour, particularly under cognitive load. Route previewing may support visual motor planning, but its effects under dual task conditions in older adults are not well understood. Research Question: Does cognitive dual tasking influence gait and gaze behaviour during adaptive walking in older adults, and does previewing the walking route before gait initiation mitigate these effects? Methods: Thirty nine community dwelling older adults (Mage=73.4 years, SD=8.1; 14 male) completed four adaptive walking conditions, combining single and dual-task walking with and without previewing. Per condition, participants completed six trials across different 8-m long coloured walking routes. Gait characteristics were assessed using an instrumented walkway and video-analysis, while gaze behaviour was recorded using mobile eye tracking. Cognitive load was manipulated using a serial subtraction task. Gait and gaze outcomes were evaluated using linear mixed effects models. Results: Dual task performance significantly increased stepping errors, cross-steps, and double limb support, while reducing stride length (p < .001). It also significantly increased the number and duration of task irrelevant fixations (p < .001). After previewing, participants exhibited more efficient gaze behaviour, as evidenced by looking further ahead (larger forward gaze transitions) and fewer irrelevant gaze fixations (p < .002). Significant Task-by-Preview interactions revealed that previewing mitigated the negative effects of dual-tasking on stepping errors and cross steps (p < .001). Significance: Route previewing prior to gait initiation attenuates negative effects of cognitive load on adaptive gait in older adults, likely by supporting visual motor planning. These findings highlight the potential value of simple visual planning interventions for improving adaptive gait in older adults.