Virtual Walking Research Articles

Human Posture Detection Method Based on Wearable Devices

The dynamic detection of human motion is important, which is widely applied in the fields of motion state capture and rehabilitation engineering. In this study, based on multimodal information of surface electromyography (sEMG) signals of upper limb and triaxial acceleration and plantar pressure signals of lower limb, the effective virtual driving control and gait recognition methods were proposed. The effective way of wearable human posture detection was also constructed. Firstly, the moving average window and threshold comparison were used to segment the sEMG signals of the upper limb. The standard deviation and singular values of wavelet coefficients were extracted as the features. After the training and classification by optimized support vector machine (SVM) algorithm, the real-time detection and analysis of three virtual driving actions were performed. The average identification accuracy was 90.90%. Secondly, the mean, standard deviation, variance, and wavelet energy spectrum of triaxial acceleration were extracted, and these parameters were combined with plantar pressure as the gait features. The optimized SVM was selected for the gait identification, and the average accuracy was 90.48%. The experimental results showed that, through different combinations of wearable sensors on the upper and lower limbs, the motion posture information could be dynamically detected, which could be used in the design of virtual rehabilitation system and walking auxiliary system.

Virtual Walking With Omnidirectional Movies and Foot Vibrations: Scene-Congruent Vibrations Enhance Walking-Related Sensations and Ground Material Perceptions

Walking is a human need. Even when physical disabilities or social situations, such as the COVID-19 pandemic, prevent people from walking, virtual reality can provide an opportunity for virtual walking or travel. In this study, a virtual walking system was developed in which users view omnidirectional movies while receiving scene-congruent vibrations to their left and right forefeet and heels. The timings of foot vibrations were generated by estimating the camera motion trajectory with visual simultaneous localization and mapping (visual SLAM) applied to four omnidirectional movies. Congruent vibration patterns were prepared for four ground scenes. Modulation of walking-related sensations and ground material perceptions by congruent and incongruent vibrations was verified using psychological measurements. The results showed that rhythmic foot vibration improved the sensations of self-motion, walking, leg action, and telepresence irrespective of scene–vibration congruency. Moreover, congruent vibrations were better than incongruent vibrations for walking-related sensations and telepresence in indoor corridors and snowy ground scenes. The perception of ground materials was enhanced by scene-congruent vibrations, whereas it was confused by scene-incongruent vibrations. These findings suggest that vibration patterns do not necessarily need to match the ground exactly to induce virtual walking sensations; however, scene-congruent or similar vibrations improve virtual walking sensations and ground material perception. By applying our methods, we can convert various public omnidirectional movies into realistic virtual walking experiences.

Development of a speed protector to optimize user experience in 3D virtual environments

Virtual walking in virtual environments (VEs) requires locomotion interfaces, especially when the available physical environment is smaller than the virtual space due to virtual reality facilities limitations; many navigation approaches have been proposed according to different input conditions, target selection and speed selection. With current technologies, the virtual locomotion speed for most VR systems relies primarily on rate-control devices (e.g., joystick). The user has to manage manual adaptation of the speed, based on the size of the VE and personal preferences. However, this method cannot provide optimal speeds for locomotion as the user tends to change the speed involuntarily due to non-desired issues including collisions or simulator sickness; in this case, the user may have to adjust the speed frequently and unsmoothly, worsening the situation. Therefore, we designed a motion protector that can be embedded into the locomotion system to provide optimal speed profiles. The optimization process aims at minimizing the total jerk when the user translates from an initial position to a target, which is a common rule of the human motion model. In addition to minimization, we put constraints on speed, acceleration and jerk so that they do not exceed specific thresholds. The speed protector is formulated mathematically and solved analytically in order to provide a smooth navigation experience with a minimum jerk of trajectory. The assessment of the speed protector was conducted in a user study measuring user experience with a simulator sickness questionnaire, event-related skin conductance responses (ER-SCR), and a NASA-TLX questionnaire, showing that the designed speed protector can provide more natural and comfortable user experience with appropriate acceleration and jerk as it avoids abrupt speed profiles.

Biopsychosocial determinants of visuospatial memory performance according to different spaces

Visuospatial memory (VSM) performance depends on intrinsic (biopsychosocial parameters) and extrinsic (space) factors. We aimed at characterizing the determinants of VSM performance according to space. Young healthy adults, 20 males and 41 females (23 ± 3 years old), were assessed for VSM performance through a pathway learning task, in reaching (eCorsi Block Tapping task) and walking space (Virtual Walking Corsi Task). We evaluated psychosocial factors through seven questionnaires – Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Fatigue Severity Scale, Profile of the Mood States, 2nd edition, short version, Coping Inventory for Stressful Situations, Measurement of Ambiguity Tolerance, Motives for Physical Activities Measure-Revised, mental rotation capabilities and locomotor characteristics (physical activity level through embedded trackers and the International Physical Activity Questionnaire, and gait parameters). The most explanatory biopsychosocial determinants of VSM performance were i) mental rotation capabilities and fatigue indicator in reaching space, and ii) mental rotation capabilities and physical activity level (tracked active energy expenditure only) in walking space. These results suggest that specific parameters should be preferred for the evaluation and strengthening of VSM capabilities in both reaching or walking spaces.

Eyes wide shut: How visual cues affect brain patterns of simulated gait.

In the last 20 years, motor imagery (MI) has been extensively used to train motor abilities in sport and in rehabilitation. However, MI procedures are not all alike as much as their potential beneficiaries. Here we assessed whether the addition of visual cues could make MI performance more comparable with explicit motor performance in gait tasks. With fMRI we also explored the neural correlates of these experimental manipulations. We did this in elderly subjects who are known to rely less on kinesthetic information while favoring visual strategies during motor performance. Contrary to expectations, we found that the temporal coupling between execution and imagery times, an index of the quality of MI, was less precise when participants were allowed to visually explore the environment. While the brain activation patterns of the gait motor circuits were very similar in both an open‐eyed and eye‐shut virtual walking MI task, these differed for a vast temporo‐occipito‐parietal additional activation for open‐eyed MI. Crucially, the higher was the activity in this posterior network, the less accurate was the MI performance with eyes open at a clinical test of gait. We conclude that both visually‐cued and internally‐cued MI are associated with the neurofunctional activation of a gait specific motor system. The less precise behavioral coupling between imagined and executed gait while keeping eyes open may be attributed to the processing load implied in visual monitoring and scanning of the environment. The implications of these observations for rehabilitation of gait with MI are discussed.

A Multidimensional Data Acquisition as a Preliminary Step to the Secondary Prevention of the Loss of Autonomy for Patients with Traumatic Injury and Stroke: An AMISIA Pilot Study

BackgroundThe aim of our study was to conduct an ad hoc data collection in healthy adults with the intention of extracting individual profiles to study the ability to effectively monitor one's health by extracting relevant indicators. As “each patient is a unique case”, AMISIA (Defi CNRS AUTON project) proposes an integrated approach, combining medical health devices, information technology, and human factors to provide patients, health care actors and family caregivers with both the best incentives and a high degree of monitoring. MethodWe conducted a data collection experiment in Limoges with 61 participants at the Limoges University. Data were biographic elements, socio-economic profiles, cognitive performance (Corsi test results), a psychological battery (anxiety, fatigue, sleep), posture and gait measurement with 4 Imus and a Wii-balance board, and finally physical activity during a week at home (Armband sensors). ResultsFor the Corsi virtual walking test, the median memory span for Group A was significantly less (p<0.001) than for Group B. Step count and active energy expenditure were significantly higher in Group B (p<0.05). A multiple regression analysis showed that gender, active energy expenditure, fatigue and tendency to play video games account for 41% of the memory span variance. ConclusionWe have shown that encouraging physical activity can be based on the knowledge of many parameters, such as weight, age, gender and other bio-psycho-social parameters that must also be included in the model.

PAM7 DEVELOPING AN AUTOMATED VIRTUAL WALKING COACH FOR UNDERSERVED, SEDENTARY PATIENTS IN PRIMARY CARE: ANALYSIS OF PILOT DATA

Scalable, accessible interventions to increase physical activity in underserved patients are needed. We pilot-tested an mHealth intervention to help ethnic-minority patients set weekly walking goals, ultimately aiming to create an automated virtual walking coach.

가상의 도보환경에서 근거리 작업 후 폭주기능의 변화와 자각증상과의 상관관계

가상의 도보환경에서 근거리 작업 후 폭주기능의 변화와 자각증상과의 상관관계

How aging affects the premotor control of lower limb movements in simulated gait.

Gait control becomes more demanding in healthy older adults, yet what cognitive or motor process leads to this age‐related change is unknown. The present study aimed to investigate whether it might depend on specific decay in the quality of gait motor representation and/or a more general reduction in the efficiency of lower limb motor control. Younger and older healthy participants performed in fMRI a virtual walking paradigm that combines motor imagery (MI) of walking and standing on the spot with the presence (Dynamic Motor Imagery condition, DMI) or absence (pure MI condition) of overtly executed ankle dorsiflexion. Gait imagery was aided by the concomitant observation of moving videos simulating a stroll in the park from a first‐person perspective. Behaviorally, older participants showed no sign of evident depletion in the quality of gait motor representations, and absence of between‐group differences in the neural correlates of MI. However, while younger participants showed increased frontoparietal activity during DMI, older participants displayed stronger activation of premotor areas when controlling the pure execution of ankle dorsiflexion, regardless of the imagery task. These data suggest that reduced automaticity of lower limb motor control in healthy older subjects leads to the recruitment of additional premotor resources even in the absence of basic gait functional disabilities.

Virtual Walking Sensation by Prerecorded Oscillating Optic Flow and Synchronous Foot Vibration.

This article reports the first psychological evidence that the combination of oscillating optic flow and synchronous foot vibration evokes a walking sensation. In this study, we first captured a walker’s first-person-view scenes with footstep timings. Participants observed the naturally oscillating scenes on a head-mounted display with vibrations on their feet and rated walking-related sensations using a Visual Analogue Scale. They perceived stronger sensations of self-motion, walking, leg action, and telepresence from the oscillating visual flow with foot vibrations than with randomized-timing vibrations or without vibrations. The artificial delay of foot vibrations with respect to the scenes diminished the walking-related sensations. These results suggest that the oscillating visual scenes and synchronous foot vibrations are effective for creating virtual walking sensations.

SRAssembler: Selective Recursive local Assembly of homologous genomic regions

BackgroundThe falling cost of next-generation sequencing technology has allowed deep sequencing across related species and of individuals within species. Whole genome assemblies from these data remain high time- and resource-consuming computational tasks, particularly if best solutions are sought using different assembly strategies and parameter sets. However, in many cases, the underlying research questions are not genome-wide but rather target specific genes or sets of genes. We describe a novel assembly tool, SRAssembler, that efficiently assembles only contigs containing potential homologs of a gene or protein query, thus enabling gene-specific genome studies over large numbers of short read samples.ResultsWe demonstrate the functionality of SRAssembler with examples largely drawn from plant genomics. The workflow implements a recursive strategy by which relevant reads are successively pulled from the input sets based on overlapping significant matches, resulting in virtual chromosome walking. The typical workflow behavior is illustrated with assembly of simulated reads. Applications to real data show that SRAssembler produces homologous contigs of equivalent quality to whole genome assemblies. Settings can be chosen to not only assemble presumed orthologs but also paralogous gene loci in distinct contigs. A key application is assembly of the same locus in many individuals from population genome data, which provides assessment of structural variation beyond what can be inferred from read mapping to a reference genome alone. SRAssembler can be used on modest computing resources or used in parallel on high performance computing clusters (most easily by invoking a dedicated Singularity image).ConclusionsSRAssembler offers an efficient tool to complement whole genome assembly software. It can be used to solve gene-specific research questions based on large genomic read samples from multiple sources and would be an expedient choice when whole genome assembly from the reads is either not feasible, too costly, or unnecessary. The program can also aid decision making on the depth of sequencing in an ongoing novel genome sequencing project or with respect to ultimate whole genome assembly strategies.

(309) Virtual Reality Walking for Neuropathic Pain in Spinal Cord Injury: Preliminary Efficacy Findings

Approximately 70% SCI patients report chronic pain, with a third characterizing their pain as debilitating. SCI-NP accompanies 40%-60% of SCI cases and is regarded as more severe than nociceptive pain. SCI-NP remains minimally responsive to existing pharmacological and nonpharmacological treatments. Pharmacological agents (e.g., antidepressants, antiepileptics, opioids) provide only a third of patients’ 50% pain reduction and present significant side effects including constipation, toxification, and addiction. Visual feedback (e.g., “mirror”) therapies have shown promise in addressing SCI-NP. These therapies target post-injury cortical changes associated with NP by reinstating sensory input via visual illusion. Preliminary studies utilizing “illusory walking” – wherein participants experience the illusion of normal gait were associated with reduced NP in individuals with SCI. The current study comprised initial feasibility and efficacy testing of the first fully immersive VR walking interface, which allows individuals with SCI-NP to control virtual legs using gait-related arm movement. The goal-directed nature of this interface aims to address key efficacy limitations of existing illusory walking interventions, which have relied exclusively on passive observation. Participants (9 male, mean time since injury=16yrs) had complete paraplegia with disruptive SCI NP. Intervention occurred over 10 days, with two 5-10 minute in-home sessions per day. NP intensity was recorded using the Neuropathic Pain Scale (NPS) and Numerical Rating Scale (0-10 NRS) prior to and following the 10-day intervention. Participants showed statistically significant declines in NPS (F(1,9)=18.51, p

Effects of virtual walking on spinal cord injury-related neuropathic pain: A randomized, controlled trial.

This study is an examination of the efficacy of a virtual walking protocol to treat spinal cord injury (SCI)-related pain. A total of 59 individuals with SCI and neuropathic pain (NP) were randomly assigned to receive 20 min of virtual walking, the treatment condition, or virtual wheeling, the control condition. Although having NP was a requirement to participate in the study, participants also underwent pain classification of up to 3 worst pain sites to also examine the effects of virtual walking on nonneuropathic pain. Pain outcomes included changes in pain severity across all pain types, NP unpleasantness, and severity of various sensory qualities of NP. This was a randomized, controlled, single-blinded trial. There was no significant difference in change in pain between groups, though there was a significant pre- to posttreatment reduction across all pain types in the virtual walking condition, but not the control condition. Specific to NP, there was a significant reduction in pain unpleasantness, but not neuropathic pain intensity. NP experienced as "cold," "deep," and with increased skin sensitivity were significantly reduced following virtual walking compared with the control condition. Results from this trial suggest that virtual walking treatment may benefit certain aspects of NP, such as associated unpleasantness, as well as certain sensory qualities of that pain. Efficacy of this treatment modality to reduce overall pain severity remains unclear, and may be modulated by other injury, individual, or personality characteristics. (PsycINFO Database Record (c) 2019 APA, all rights reserved).

Virtual reality for spinal cord injury-associated neuropathic pain: Systematic review.

Treatment of spinal cord injury (SCI)-associated neuropathic pain is challenging, with limited efficacy and no definitive options, and SCI patients often show resistance to pharmacologic treatment. Virtual reality (VR) therapy is a non-invasive, non-pharmacologic alternative with minimal adverse effects. To investigate the effect of VR therapy on SCI-associated neuropathic pain in a systematic review. Articles needed to 1) be written in English; 2) include adult subjects, with at least half the study population with a SCI diagnosis; 3) involve any form of VR therapy; and 4) assess neuropathic pain by quantitative outcome measures. Articles were searched in MEDLINE/PubMed, CINAHL®, EMBASE, and PsycINFO up to April 2018. Reference lists of retrieved articles were hand-searched. Methodologic quality was assessed by the Physiotherapy Evidence Database Score (PEDro) for randomized controlled trials and Modified Downs and Black Tool (D&B) for all other studies. Level of evidence was determined by using a modified Sackett scale. Among 333 studies identified, 9 included in this review (n=150 participants) evaluated 4 methods of VR therapy (virtual walking, VR-augmented training, virtual illusion, and VR hypnosis) for treating neuropathic pain in SCI patients. Each VR method reduced neuropathic pain: 4 studies supported virtual walking, and the other 3 VR methods were each supported by a different study. Combined treatment with virtual walking and transcranial direct current stimulation was the most effective. The quality of studies was a major limitation. VR therapy could reduce SCI-associated neuropathic pain, although the clinical significance of this analgesic effect is unclear. Clinical trials evaluating VR therapy as standalone and/or adjunct therapy for neuropathic pain in SCI patients are warranted.

A RE-AIM evaluation of a workplace physical activity microgrant initiative: The 10,000 steps workplace challenge

Introduction: 10,000 Steps is a freely accessible online physical activity promotion website. The Workplace Challenge, which encourages employees to form teams and complete a virtual walking challenge, is a key promotion strategy. The cost of providing pedometers to workers poses a financial barrier to many workplaces seeking to participate. To address this, the 10,000 Steps Pedometer Microgrant Scheme, which provided pedometers to participating workplaces, was trialled and evaluated. This study assesses the reach, effectiveness, adoption, implementation and maintenance of the Microgrant Scheme using RE-AIM.

Virtual Reality, Visual Cliffs, and Movement Disorders.

We outline an experimental setup designed to dynamically understand neural responses to visual cliffs while walking. The goal of our work is understanding and mitigating fear of falling, particularly among the elderly. In our setup, an EEG cap monitors a subject's neural activity while the subject is immersed in a virtual world and walking on an instrumented treadmill. The subject's response to visual stimuli is measured by both the EEG cap and by speed and pressure data from the treadmill. Based on this data, we can dynamically alter the landscape in the virtual world. We hope that our setup may be useful in helping subjects develop mechanisms to compensate for significant fear of falling while walking.

The influence of age in women in visuo-spatial memory in reaching and navigation tasks with and without landmarks

Spatial memory and navigation capabilities tend to decline in normal aging, but few studies have assessed the impact of landmarks on route learning in a large-scale environment. The objectives were to examine age-related effects on visuo-spatial working memory capabilities in various environments and to determine the impact of landmarks in navigation skills in normal aging. 42 young women (23.6 ± 4.9 years) and 37 older women (70.7 ± 4.7 years) with no cognitive impairment have performed three visuo-spatial working memory tests: one in reaching space (computerized Corsi-Block-Tapping test) and two in locomotor navigation space (a condition without landmarks: Virtual Walking Corsi Test and a condition with landmarks: Virtual Room Walking Test). A two-way mixed ANOVA test showed that the young subjects performed better in all conditions than older subjects. The performance in visuo-spatial working memory thus decreases with age. Visuo-spatial working memory performances were identical in reaching and navigation spaces for both groups. The integration of landmarks into a navigational task decreases performance in older women, while this performance is not altered in younger women.

You Spin my Head Right Round: Threshold of Limited Immersion for Rotation Gains in Redirected Walking.

In virtual environments, the space that can be explored by real walking is limited by the size of the tracked area. To enable unimpeded walking through large virtual spaces in small real-world surroundings, redirection techniques are used. These unnoticeably manipulate the user's virtual walking trajectory. It is important to know how strongly such techniques can be applied without the user noticing the manipulation-or getting cybersick. Previously, this was estimated by measuring a detection threshold (DT) in highly-controlled psychophysical studies, which experimentally isolate the effect but do not aim for perceived immersion in the context of VR applications. While these studies suggest that only relatively low degrees of manipulation are tolerable, we claim that, besides establishing detection thresholds, it is important to know when the user's immersion breaks. We hypothesize that the degree of unnoticed manipulation is significantly different from the detection threshold when the user is immersed in a task. We conducted three studies: a) to devise an experimental paradigm to measure the threshold of limited immersion (TLI), b) to measure the TLI for slowly decreasing and increasing rotation gains, and c) to establish a baseline of cybersickness for our experimental setup. For rotation gains greater than 1.0, we found that immersion breaks quite late after the gain is detectable. However, for gains lesser than 1.0, some users reported a break of immersion even before established detection thresholds were reached. Apparently, the developed metric measures an additional quality of user experience. This article contributes to the development of effective spatial compression methods by utilizing the break of immersion as a benchmark for redirection techniques.

Feature Extraction of Brain Activity Information for Virtual Walking Directional Intention Recognition

Feature Extraction of Brain Activity Information for Virtual Walking Directional Intention Recognition

Proposal of walking training method with virtual walking model

Proposal of walking training method with virtual walking model