Quantification of gait changes in subjects with visual height intolerance when exposed to heights

Abstract

Introduction: Visual height intolerance (vHI) manifests as instability at heights with apprehension of losing balance or falling. We investigated contributions of visual feedback and attention on gait performance of subjects with vHI.Materials and Methods: Sixteen subjects with vHI walked over a gait mat (GAITRite®) on a 15-m-high balcony and at ground-level. Subjects walked at different speeds (slow, preferred, fast), during changes of the visual input (gaze straight/up/down; eyes open/closed), and while doing a cognitive task. An rmANOVA with the factors “height situation” and “gait condition” was performed. Subjects were also asked to estimate the height of the balcony over ground level. The individual estimates were used for correlations with the gait parameters.Results: Study participants walked slower at heights, with reduced cadence and stride length. The double support phases were increased (all p < 0.01), which correlated with the estimated height of the balcony (R2 = 0.453, p < 0.05). These changes were still present when walking with upward gaze or closure of the eyes. Under the conditions walking and looking down to the floor of the balcony, during dual-task and fast walking, there were no differences between the gait performance on the balcony and at ground-level.Discussion: The found gait changes are features of a cautious gait control. Internal, cognitive models with anxiety play an important role for vHI; gait was similarly affected when the visual perception of the depth was prevented. Improvement by dual task at heights may be associated by a reduction of the anxiety level.Conclusion: It is conceivable that mental distraction by dual task or increasing the walking speed might be useful recommendations to reduce the imbalance during locomotion in subjects susceptible to vHI.

Cathodal Transcranial Direct Current Stimulation (tDCS) to the Right Cerebellar Hemisphere Affects Motor Adaptation During Gait

“…This is consistent with studies that have shown patients with cerebellar ataxia to perform worse when walking at speeds slower than normal relative to faster, possibly due to greater sensory demands and/or greater demands placed on balance brought about through inertia [46]. Furthermore, the Lo template was designed to be more challenging than the Sh by using more extreme variations in step lengths.…”

Preferred walking speed on rough terrain; is it all about energetics?

“…In summary, based on both the current findings, which show a difference between the speed that minimizes the COT and the preferred speed on rough terrain, and previous research (Brown et al, 2002;Clark-Carter et al, 1986;Monsch et al, 2012;Schniepp et al, 2014), it seems that simply minimizing COT does not fully represent the human objective function for walking speed. Other walking conditions should be examined to investigate additional parameters that might appear in the cost function, such as stability, reward and time-saving (Summerside, et al, 2018).…”

“…Monsch et al (2012) found that when instructed to walk downhill with a 'loose relaxed gait', subjects had a lower COT than when walking with their natural, preferred gait without any instructions. Similarly, it was found that people walk more slowly on a smooth surface when it is elevated above the ground (Brown et al, 2002;Schniepp et al, 2014) and thus presumably they chose not to walk at the energetic COT minimum. Kalantarov et al (2018) found that pedestrians crossing a street increased their walking speed when the time gap between cars was smaller.…”

“…Second, walking on rough terrain intrinsically requires the person to consider their stability while walking. Although there is no explicit model for stability as a function of speed on rough terrain, we know from experience that humans tend to walk slower when there is a greater consequence of falling (Brown et al, 2002;Schniepp et al, 2014). Thus, we hypothesized that on rough terrain, the preferred walking speed would be slower than on smooth terrain and slower than the metabolic COT minimum speed.…”

Fear of Heights and Visual Height Intolerance in Children 8–10 Years Old

“…Walking is slow and cautious [40,41]. Anxiety appears to be the critical symptom that causes the typical, but non-specific eye and motor behavior which can be described as tonic immobility [6].…”