Vision Affects Gait Speed but not Patterns of Muscle Activation During Inclined Walking—A Virtual Reality Study

Benady, Amit; Zadik, Sean; Ben-Gal, Oran; Porras, Desidério Cano; Wenkert, Atalia; Gilaie-Dotan, Sharon; Plotnik, Meir

doi:10.3389/fbioe.2021.632594

Cited by 4 publications

(22 citation statements)

References 54 publications

(78 reference statements)

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“…Specifically, given the expected gravity induced acceleration forces acting upon the body when walking on actual inclined surfaces, we anticipated smaller visually induced braking/exertion effects for smaller slopes (±5°) as compared to the effect expected when walking under the illusion of bigger slopes (±15°). We defined an additional objective for this study, to confirm our previous observation ( 9 ), that the magnitude of visual modulation on gait speed during virtual surface inclination changes of 10 degrees varies across people and is related to the individual's subjective visual misperception of verticality, as measured by the rod and frame test.…”

Section: Introductionmentioning

confidence: 69%

“…The different experimental apparatuses were elaborately described in our previous work ( 4 , 9 ). Herein is a brief description:…”

Section: Methodsmentioning

confidence: 99%

“…To compute this metric, we used data from the incongruent T L V U10 , T L V D10 , T D10 V U10 , T U10 V D10 conditions, similar to our previous study ( 9 ). For each participant the absolute values of the maximal relative (i.e., percent) change with respect to the SSV were calculated.…”

Section: Methodsmentioning

confidence: 99%

“…Body-based inputs are sensitive to real gravitational forces exerted on the body when walking on inclined surfaces. Visual inputs however, are assumed to be influenced by top-down expectations likely based on prior visual experience during walking on inclined surfaces ( 4 , 9 ). The sensory reweighting mechanism suggests that each of the sensory inputs has a specific “weight.” The weighted inputs are added up to produce a behavioral modulation.…”

Section: Introductionmentioning

confidence: 99%

“…Therefore, to evaluate the contribution of visual inputs to locomotion there is a need to artificially manipulate them in an independent manner from the body-based inputs and examine their relative “weight.” While reweighting changes have been broadly described under steady-state conditions, evidence is lacking regarding the dynamics of reweighting following transitions to various intensities of sensory inputs during locomotion. To that end, we used a novel paradigm recently presented by our lab, which allows dissociating visual inputs from body-based inputs ( 4 , 9 ). We transitioned the visual scene's apparent inclination independently of the physical inclination of the treadmill.…”

Section: Introductionmentioning

confidence: 99%

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Gait Speed Modulations Are Proportional to Grades of Virtual Visual Slopes—A Virtual Reality Study

et al. 2021

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Gait is a complex mechanism relying on integration of several sensory inputs such as vestibular, proprioceptive, and visual cues to maintain stability while walking. Often humans adapt their gait to changes in surface inclinations, and this is typically achieved by modulating walking speed according to the inclination in order to counteract the gravitational forces, either uphill (exertion effect) or downhill (braking effect). The contribution of vision to these speed modulations is not fully understood. Here we assessed gait speed effects by parametrically manipulating the discrepancy between virtual visual inclination and the actual surface inclination (aka visual incongruence). Fifteen healthy participants walked in a large-scale virtual reality (VR) system on a self-paced treadmill synchronized with projected visual scenes. During walking they were randomly exposed to varying degrees of physical-visual incongruence inclinations (e.g., treadmill leveled & visual scene uphill) in a wide range of inclinations (−15° to +15°). We observed an approximately linear relation between the relative change in gait speed and the anticipated gravitational forces associated with the virtual inclinations. Mean relative gait speed increase of ~7%, ~11%, and ~17% were measured for virtual inclinations of +5°, +10°, and +15°, respectively (anticipated decelerating forces were proportional to sin[5°], sin[10°], sin[15°]). The same pattern was seen for downhill virtual inclinations with relative gait speed modulations of ~-10%, ~-16%, and ~-24% for inclinations of −5°, −10°, and −15°, respectively (in anticipation of accelerating forces). Furthermore, we observed that the magnitude of speed modulation following virtual inclination at ±10° was associated with subjective visual verticality misperception. In conclusion, visual cues modulate gait speed when surface inclinations change proportional to the anticipated effect of the gravitational force associated the inclinations. Our results emphasize the contribution of vision to locomotion in a dynamic environment and may enhance personalized rehabilitation strategies for gait speed modulations in neurological patients with gait impairments.

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Section: Introductionmentioning

confidence: 69%

“…The different experimental apparatuses were elaborately described in our previous work ( 4 , 9 ). Herein is a brief description:…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Gait Speed Modulations Are Proportional to Grades of Virtual Visual Slopes—A Virtual Reality Study

et al. 2021

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Mixed reality and sensor real-time feedback to increase muscle engagement during deep core exercising

Lancere

Jürgen²,

Gapeyeva³

2023

Virtual Reality

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In lower extremity amputee rehabilitation programs, difficult-to-master targeted activation of deep core muscles and pursed-lip breathing training are prescribed to treat poor movement quality and to improve recovery after amputation. Non-invasive wireless sensors and mixed reality (MR) technologies are proposed as a solution. The main aim was to validate a novel rehabilitation technology by exploring whether a combined verbal and visual mixed reality feedback (VF + MR) will initiate a greater change in muscle electrical activation magnitude compared to verbal feedback only (VF) during exercising. The second objective was to evaluate the effectiveness of specific exercise program targeted to engage specifically deep core muscles. Pre-post-test cross-over study involved electromyographic activity (EMG) analysis from Transversus Abdominis (TA) and Multifidus (MF) muscles and self-reported questionnaires to evaluate the efficiency of MR feedback. Anthropometric data, state of health, subjective low back pain (Oswestry Disability Index), and physical activity level (IPAQ) estimation were analysed. The data from 13 patients following unilateral transtibial and transfemoral amputation showed a significant EMG increase in (VF + MR) for Chair Lean (p = 0.03) and Bent Leg Raise (p = 0.0005) exercises for TA muscle. Even though there was no significant difference in Back Bridge and Side Plank exercises, 6 to 10 participants depending on the exercise, had an increase of EMG in the range of 50–400% for both – TA and MF muscles. The proposed solution has a high potential for increasing motivation, self-awareness, and muscle engagement during exercises, based on EMG and self-reported questionnaire data.

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The effect of virtual visual scene inclination transitions on gait modulation in healthy young vs older adults - a virtual reality study

Benady

Zadik

Gilaie-Dotan

et al. 2023

Preprint

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Bipedal locomotion requires body adaptation to maintain stability after encountering a transition to inclined walking. A major adaptation is the change in walking speed to maintain optimal energy consumption. When transitioning to uphill walking, people exert more energy to counteract gravitational forces pulling them backward, while when transitioning to downhill walking people break to avoid uncontrolled acceleration. This behavior is controlled by three main senses: proprioception and vestibular (aka body-based cues), and visual cues. In this study, we aimed to measure the influence of the visual cues on these modulations in healthy older adults and compare it to healthy young adults. To that end, we used a fully immersive virtual-reality system embedded with a self-paced treadmill and projected visual scene that allowed us to manipulate the inclinations of the treadmill and the visual scene in an independent manner. In addition, we measured the visual field dependency of each participant using the rod and frame test. The group of older adults presented the braking (decelerating), and exertion (accelerating) effects, in response to downhill and uphill visual illusions, respectively, in a similar manner as the young group. Furthermore, we found a significant correlation between the intensity of the speed modulation and the visual field dependency for each group separately, however the visual field dependency was significantly higher in the elderly adults. These results suggest that with aging individuals maintain their reliance on the visual system to modulate their gait in accordance with surface inclination in the same manner as young adults.

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Vision Affects Gait Speed but not Patterns of Muscle Activation During Inclined Walking—A Virtual Reality Study

Cited by 4 publications

References 54 publications

Gait Speed Modulations Are Proportional to Grades of Virtual Visual Slopes—A Virtual Reality Study

Gait Speed Modulations Are Proportional to Grades of Virtual Visual Slopes—A Virtual Reality Study

Mixed reality and sensor real-time feedback to increase muscle engagement during deep core exercising

The effect of virtual visual scene inclination transitions on gait modulation in healthy young vs older adults - a virtual reality study

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