Attuning one's steps to visual targets reduces comfortable walking speed in both young and older adults

Abstract

Comfortable walking speed (CWS) is indicative of clinically relevant factors in the elderly, such as fall risk and mortality. Standard CWS tests involve walking on a straight, unobstructed surface, while in reality surfaces are uneven and cluttered and so walkers rely on visually guided adaptations to avoid trips or slips. Hence, the predictive value of CWS may be expected to increase when assessed for walking in more realistic (visually guided) conditions. We examined CWS in young (n=18) and older (n=18) adults for both overground and treadmill walking. Overground CWS was assessed using the 10-meter walk test with and without visual stepping targets. For treadmill walking, four conditions were examined: (i) uncued walking, and (ii-iv) cued walking with visual stepping targets where the inter-stepping target distance varied by 0%, 20%, or 40%. Pre-experimental measures were taken so that the average inter-stepping target distance could be adjusted for each belt speed based on each participant's self-selected gait characteristics. Results showed that CWS was significantly slower when stepping targets were present in both overground (p<.001) and treadmill walking (p<.001). Thus, attuning steps to visual targets significantly affected CWS, even when the patterning of these targets matched the participant's own gait pattern (viz. 0%-treadmill-walking condition). Results from the treadmill-walking task showed that the amount of variation in inter-stepping target distance did not differentially affect CWS. Our results suggest that it may be worthwhile in clinical assessments to not only determine walking speed using standard conditions but also in situations that require visually guided stepping.

Fractal Fluctuations in Human Walking: Comparison Between Auditory and Visually Guided Stepping

“…A cause of the difficulty was perhaps that only two incoming steps were seen in advance by the subject, which could be too short a warning to anticipate precise foot placement. Peper et al 30 , using the same treadmill as in the present study, showed that individuals spontaneously chose a lower walking speed in VC condition: this corroborates the hypothesis that a sufficient reaction time to the incoming targets should be allowed to help the subject to be comfortable with VC. However, further studies are needed to analyze gait variability at different speeds under VC condition.…”

Attentional costs of walking are not affected by variations in lateral balance demands in young and older adults

“…Table 1) for other tasks. Recent studies reported slower self-selected walking speeds in visuolocomotor situations (e.g., walking on a narrow path [26] or a sequence of stepping stones [27]) compared to unconstrained walking, for young and older adults alike. This was interpreted as an adaptive strategy to favor task performance relative to the visual context [26,27].…”

“…Recent studies reported slower self-selected walking speeds in visuolocomotor situations (e.g., walking on a narrow path [26] or a sequence of stepping stones [27]) compared to unconstrained walking, for young and older adults alike. This was interpreted as an adaptive strategy to favor task performance relative to the visual context [26,27]. Given our current results, it thus seems likely that older adults slowed down their preferred walking speed to increase the available time for visuolocomotor control [28,29].…”

“…Participants had no self-reported cardiovascular or cardiopulmonar problems, orthopedic conditions, uncorrected visual or auditory impairments, neurological disease, or other conditions limiting mobility; they did not use walking aids and the Mini Mental State Exam score for the older participants exceeded 23 (range [24][25][26][27][28][29][30]. All participants provided written informed consent before participation.…”

Dual-Task Walking in Challenging Environments in People with Stroke: Cognitive-Motor Interference and Task Prioritization

“…The two challenging walking environments differed with regard to the type of context: a stationary physical context versus suddenly appearing projector-augmented visual context. The latter context was included as projector-augmented walking-adaptability treatment is increasingly used as part of rehabilitation after stroke [ 9 , 13 – 15 ]. We expected stronger cognitive-motor interference for the two challenging walking environments, as reflected in lower walking speeds, poorer walking-adaptability performance, and/or poorer cognitive-task performance.…”