Collision avoidance behaviours between older adult and young adult walkers.

Background: Collision avoidance between two walkers requires a mutual adaptation based on visual information in order to be successful. Age-related changes to visuomotor processing, kinesthetic input, and intersegmental dynamics increases the risk of collision and falls in older adults. However, few studies examine behavioural strategies in older adults during collision avoidance tasks with another pedestrian.

Research Question: Is there a difference between older adults' and young adults' collision avoidance behaviours with another pedestrian?

Methods: Seventeen older adults (x¯ = 68 ± 3 years) and seventeen young adults (x¯ = 23 ± 2 years) walked at a comfortable walking speed along a 12.6 m pathway while avoiding another walker. Trials were randomized equally to include 20 interactions with the same age group and 21 interactions with the opposite age group. Minimum predicted distance (mpd) was used to characterize collision avoidance behaviours between older adults and young adults.

Results: Older adults had riskier avoidance behaviours, passing closer to the other pedestrian (0.79 m ± 0.18 m) compared to when two young adults were on a collision course (0.93 m ± 0.17 m) (χ²(3) = 35.94, p < .0001). Whenever an older adult was on a collision course with a young adult, the young adult contributed more to the avoidance regardless of passing order.

Significance: The results from the current study highlight age-related effects during a collision avoidance task in older adults resulting in risky behaviour and a potential collision. Future studies should further investigate age-related visuomotor deficits during collision avoidance tasks in cluttered environments using virtual reality in order to tease out factors that contribute most to avoidance behaviours in older adults.