Gaze strategies for avoiding obstacles: Differences between young and elderly subjects

Abstract

1Visual input is highly relevant for safely stepping over obstacles. In this study, gaze-2 behaviour was investigated in elderly, middle-aged and young subjects as they walked on 3 a treadmill repeatedly stepping over obstacles, which approached either on the right or 4 left side. In between obstacle-steps, subjects visually fixated a target N or F located two 5 or four steps ahead on the floor, respectively. An acoustic warning signal announced the 6 obstacles, after which subjects were free to look wherever they wanted. Gaze-movements 7were measured by video-oculography. Four conditions with 20 obstacles were conducted 8 (two with target N, two with target F). In two conditions, high-precision stepping was 9 investigated by asking subjects to step with minimal foot-clearance over the obstacles, 10 while receiving acoustic feedback about their performance. In the high-precision 11 conditions, more subjects (target N: 70%, target F: 81%) turned their gaze on the 12 obstacles and for a longer time than in unrestricted conditions. When fixating on the near 13 target N and unrestricted stepping over the obstacles, significantly more elderly subjects 14 (85%) turned their gaze on the obstacle compared to middle-aged (17%) and young 15 subjects (29%).The elderly turned their gaze earlier and longer on the obstacle than 16 middle-aged or young subjects. Our results reveal a different gaze-behaviour strategy of 17 elderly subjects suggesting a greater dependency on visual inputs.

Glaucoma-Related Differences in Gaze Behavior When Negotiating Obstacles

“… 42 When stepping over an obstacle, normally sighted older adults shift gaze to the obstacle earlier and for longer than young adults. 43 , 44 However, spending more time fixating an obstacle when having to avoid it, rather than when having to step over it, is not necessarily an ideal strategy. This is because there is a natural tendency to veer in the direction you look; that is, you look where you want to go.…”

Real-World Navigation With Application: Characteristics of Gaze Behavior and Associated Factors in Older Adults

“…Considering the t -test family, α = 0.05, effect size = 0.90, and power = 0.80 for normally distributed data. The effect size was set with reference to the values reported in previous studies of age-related gaze behavior ( Chaby et al, 2017 ; Domínguez-Zamora et al, 2020 ; Keller Chandra et al, 2011 ). In these conditions, the sample size required to complete the study was 32 people total, and 16 people for each group.…”

Patients with knee osteoarthritis have altered gait and gaze patterns compared to age-matched controls: A pilot study

“…Shorter duration of fixation is displayed by participants identified as fallers and participants with KOA during the TUGA task thus suggesting the KOA may be a subgroup of the heterogenous fallers. Previous work has highlighted that the gaze behaviour of individuals with dysfunctional locomotion (i.e., older adults at higher risk of falls) often demonstrate premature fixation away from the target they are stepping towards, in order to fixate on a proximal location in their walking trajectory [26,35]. These gaze strategies are thought to represent a prioritization of visual information used to consciously control each locomotor action [26].…”