Vision, cognition, and walking stability in young adults

Yogev Koren,Ohad Ben-Shahar,Yisrael Parmet,Rotem Mairon,Simona Bar-Haim,Ilay Sofer

doi:10.1038/s41598-021-04540-w

Abstract

Downward gazing is often observed when walking requires guidance. This gaze behavior is thought to promote walking stability through anticipatory stepping control. This study is part of an ongoing effort to investigate whether downward gazing also serves to enhance postural control, which can promote walking stability through a feedback/reactive mechanism. Since gaze behavior alone gives no indication as to what information is gathered and the functions it serves, we aimed to investigate the cognitive demands associated with downward gazing, as they are likely to differ between anticipatory and feedback use of visual input. To do so, we used a novel methodology to compromise walking stability in a manner that could not be resolved through modulation of stepping. Then, using interference methodology and neuroimaging, we tested for (1) interference related to dual tasking, and (2) changes in prefrontal activity. The novel methodology resulted in an increase in the time spent looking at the walking surface. Further, while some dual-task interference was observed, indicating that this gaze behavior is cognitively demanding, several gaze parameters pertaining to downward gazing and prefrontal activity correlated. These correlations revealed that a greater tendency to gaze onto the walking surface was associated with lower PFC activity, as is expected when sensory information is used through highly automatic, and useful, neural circuitry. These results, while not conclusive, do suggest that gazing onto the walking surface can be used for purposes other than anticipatory stepping control, bearing important motor-control and clinical implications.

Highlights

Downward gazing is often observed when walking requires guidance
In this study we explore the cognitive demands and prefrontal cortex (PFC) activity associated with walking instability
We aimed to investigate the association of these cognitive demands with downward gazing behavior, under the same conditions reported by Koren et al.[35]; the underlying assumption was that the cognitive demands should be different if visual information is used for anticipatory stepping control, as opposed to feedback/reactive postural control

Summary

Introduction

Downward gazing is often observed when walking requires guidance. This gaze behavior is thought to promote walking stability through anticipatory stepping control. While some dual-task interference was observed, indicating that this gaze behavior is cognitively demanding, several gaze parameters pertaining to downward gazing and prefrontal activity correlated These correlations revealed that a greater tendency to gaze onto the walking surface was associated with lower PFC activity, as is expected when sensory information is used through highly automatic, and useful, neural circuitry. Walking gaze behavior has been suggested to provide information used, primarily, in an anticipatory manner to plan future actions/steps[17], and to guide ongoing o nes[18] This indicates that attention and possibly other cognitive resources are required to acquire, process, and use visual information to control gait (i.e., plan or guide subsequent or current step/s). This observed effect is similar to those observed for deficits in other sensory modalities, which largely support walking through feedback control loops (reviewed in2) and indicate that when sensory information required to control walking is inadequate or absent, automaticity decreases

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