Effects of wearing a head-mounted display during a standard clinical test of dynamic balance

Comparing Walking-Related Everyday Life Tasks of Children with Gait Disorders in a Virtual Reality Setup With a Physical Setup: Cross-Sectional Noninferiority Study

BACKGROUND

A frequent rehabilitation goal for children with gait disorders is to practice daily-life walking activities. Unfortunately, these are often difficult to practice in a conventional therapeutic setting. Virtual reality (VR) with head-mounted displays (HMDs) could be a promising approach in neurorehabilitation to train such activities in a safe environment. First, however, we must know whether obstacles in VR are indeed mastered as obstacles.

OBJECTIVE

This study aimed to provide information on whether VR is feasible and motivating to induce and practice movements needed to master real obstacles in children and adolescents with gait disorders. Furthermore, this project aims to evaluate which kinds of everyday walking activities are appropriate to be practiced in VR.

METHODS

In this cross-sectional study, participants stepped over a bar, crossed a gap, balanced over a beam, and circumvented stationary obstructions arranged in a course under real physical and virtual conditions wearing a VR HMD. We recorded the respective primary outcomes (step height, step length, step width, and minimal shoulder-obstacle distance) with motion capture. We then calculated the mean differences and 95% CI of the spatiotemporal parameters between the VR and physical setup and later compared them using noninferiority analysis with margins defined a priori by a clinical expert panel. Additionally, the participants responded to a standardized questionnaire while the therapists observed and evaluated their movement performance.

RESULTS

We recruited 20 participants (mean age 12.0, range 6.6-17.8 years) with various diagnoses affecting their walking ability. At 3.77 (95% CI 1.28 to 6.26) cm, the mean difference in step height of the leading foot in the overstepping task did not exceed the predefined margin of -2 cm, thus signifying noninferiority of the VR condition compared to mastering the physical obstacles. The same was true for step length (-1.75, 95% CI -4.91 to 1.41 cm; margin -10 cm), step width (1.05, 95% CI 0.20 to -1.90 cm; margin 3 cm), and the minimal shoulder-obstacle distance (0.25, 95% CI -0.85 to 0.35 cm; margin -2 cm) in the other tasks. Only the trailing foot in the overstepping task yielded inconclusive results.

CONCLUSIONS

Children with gait disorders perform everyday walking tasks like overstepping, crossing, balancing, or circumventing similarly in physical and VR environments, suggesting that VR could be a feasible therapeutic tool to practice everyday walking tasks.

Vestibular perceptual testing from lab to clinic: a review

Not all dizziness presents as vertigo, suggesting other perceptual symptoms for individuals with vestibular disease. These non-specific perceptual complaints of dizziness have led to a recent resurgence in literature examining vestibular perceptual testing with the aim to enhance clinical diagnostics and therapeutics. Recent evidence supports incorporating rehabilitation methods to retrain vestibular perception. This review describes the current field of vestibular perceptual testing from scientific laboratory techniques that may not be clinic friendly to some low-tech options that may be more clinic friendly. Limitations are highlighted suggesting directions for additional research.

Comparison of Smoothness, Movement Speed and Trajectory during Reaching Movements in Real and Virtual Spaces Using a Head-Mounted Display

Virtual reality is used in rehabilitation and training simulators. However, whether movements in real and virtual spaces are similar is yet to be elucidated. The study aimed to examine the smoothness, trajectory, and velocity of participants' movements during task performance in real and virtual space. Ten participants performed the same motor task in these two spaces, reaching for targets placed at six distinct positions. A head-mounted display (HMD) presented the virtual space, which simulated the real space environment. The smoothness of movements during the task was quantified and analysed using normalised jerk cost. Trajectories were analysed using the actual trajectory length normalised by the shortest distance to the target, and velocity was analysed using the time of peak velocity. The analysis results showed no significant differences in smoothness and peak velocity time between the two spaces. No significant differences were found in the placement of the six targets between the two spaces. Conversely, significant differences were observed in trajectory length ratio and peak velocity time, albeit with small effect sizes. This outcome can potentially be attributed to the fact that the virtual space was presented from a first-person perspective using an HMD capable of presenting stereoscopic images through binocular parallax. Participants were able to obtain physiological depth information and directly perceive the distance between the target and the effector, such as a hand or a controller, in virtual space, similar to real space. The results suggest that training in virtual space using HMDs with binocular disparity may be a useful tool, as it allows the simulation of a variety of different environments.

Effectiveness of virtual reality games in improving physical function, balance and reducing falls in balance-impaired older adults: A systematic review and meta-analysis

BACKGROUND

In recent years, sports games based on virtual reality (VR) have been widely used in the prevention and treatment of diseases related to the elderly. However, there seems to be no consensus on the improvement and comparison of physical function, balance and falls in elderly people with balance impairment.

OBJECTIVE

This study aims to explore the effects of VR intervention on physical function, balance and falls in elderly people with balance impairment.

METHODS

Systematic literature searches of the PubMed, Web of Science, Elsevier, Cochrane, CNKI, and Wanfang databases were performed for VR games-related randomized controlled trials or comparison studies among elderly participants with impaired balance, published in English or Chinese until March 20, 2022. The Cochrane collaboration risk of bias tool was used to evaluate the methodological quality of the studies. A meta-analysis was performed to calculate the standardized mean deviation or mean difference of the sample and its 95% confidence interval (CI) in VR games.

RESULTS

The systematic review included 23 studies. The results showed that VR intervention had significant effects on hand grip strength (MD:1.30, P = 0.040), knee extension strength (MD:-6.27, P<0.001), five times sit-to-stand test scores (MD:1.13, P = 0.030), timed up-and-go test scores (MD:-1.01, P = 0.001), berg balance scale scores (MD:2.37, P<0.001), and falls efficacy scale scores (SMD:-0.28, P = 0.020). Subgroup analysis results showed that VR intervention was more effective on improving TUG and BBS scores than the conventional exercise group (MD=-0.54, P = 0.004; MD=3.24, P<0.001) and the non-intervention group (MD=-0.98, P = 0.001; MD=3.30, P < 0.001). The balance training-based VR had a significant effect on improving TUG (MD=-1.03, P = 0.004) and BBS (MD=2.93, P<0.001), and 20-45 min intervention, ≥3 times/wk, 5-8 wk cycles were significant in improving TUG (MD=-0.89, P<0.001; MD=-0.75, P = 0.0003; MD=-1.54, P<0.0001). VR intervention significantly improved TUG (MD=-2.27, P<0.0001) and BBS (MD=3.41, P<0.0001) in older adults in the hospital or nursing home compared with those residing in communities.

CONCLUSION

VR interventions can help the elderly with impaired balance to overcome traditional sports obstacles and improve physical function, balance and minimize falls. Balance training-based VR intervention is more effective in balance recovery and fall prevention compared with game program. An intervention plan comprising 20-45 min, 5-8 wk cycles, and ≥3 times/wk frequency has significantly higher effects for high-risk elderly populations living in hospitals or nursing homes.

Dual-tasking interference is exacerbated outdoors: A pilot study

Introduction

Walking while texting can create gait disturbances that may increase fall risk, especially in outdoors environment. To date, no study has quantified the effect of texting on motor behavior using different dynamic tasks in outdoor environments. We aimed to explore the impact of texting on dynamic tasks in indoor and outdoor environments.

Methods

Twenty participants (age 38.3 ± 12.5 years, 12 F) had a Delsys inertial sensor fixed on their back and completed walk, turn, sit-to-stand, and stand-to-sit subtasks with and without texting in both indoor and outdoor environments.

Results

While there was no difference in texting accuracy (p = 0.3), there was a higher dual-tasking cost in walking time with texting outdoors than indoors (p = 0.008).

Discussion

Dual tasking has a greater impact on walking time outdoors compared to an indoor environment. Our findings highlight the importance of patient education concerning dual-tasking and pedestrian safety in clinical settings.

Design and usability of a system for the study of head orientation

The ability to control head orientation relative to the body is a multisensory process that mainly depends on proprioceptive, vestibular, and visual sensory systems. A system to study the sensory integration of head orientation was developed and tested. A test seat with a five-point harness was assembled to provide passive postural support. A lightweight head-mounted display was designed for mounting multiaxis accelerometers and a mini-CCD camera to provide the visual input to virtual reality goggles with a 39° horizontal field of view. A digitally generated sinusoidal signal was delivered to a motor-driven computer-controlled sled on a 6-m linear railing system. A data acquisition system was designed to collect acceleration data. A pilot study was conducted to test the system. Four young, healthy subjects were seated with their trunks fixed to the seat. The subjects received a sinusoidal anterior–posterior translation with peak accelerations of 0.06g at 0.1 Hz and 0.12g at 0.2, 0.5, and 1.1 Hz. Four sets of visual conditions were randomly presented along with the translation. These conditions included eyes open, looking forward, backward, and sideways, and also eyes closed. Linear acceleration data were collected from linear accelerometers placed on the head, trunk, and seat and were processed using MATLAB. The head motion was analyzed using fast Fourier transform to derive the gain and phase of head pitch acceleration relative to seat linear acceleration. A randomization test for two independent variables tested the significance of visual and inertial effects on response gain and phase shifts. Results show that the gain was close to one, with no significant difference among visual conditions across frequencies. The phase was shown to be dependent on the head strategy each subject used.

Visual Feedback in Augmented Reality to Walk at Predefined Speed Cross-Sectional Study Including Children With Cerebral Palsy

In an augmented reality environment, the range of possible real-time visual feedback is extensive. This study aimed to compare the impact of six scenarios in augmented reality combining four visual feedback characteristics on achieving a target walking speed. The six scenarios have been developed for Microsoft Hololens augmented reality headset. The four feedback characteristics that we have varied were: Color; Spatial anchoring; Speed of the feedback, and Persistence. Each characteristic could have different values (for example, the color could be unicolor, bicolor, or gradient). Participants had to walk for two consecutive walking trials for each scenario: at their maximal speed and an intermediate speed. Mean speed, percentage of time spent above or around target speed, and time to reach target speed were compared between scenarios using mixed linear models. A total of 25 children with disabilities have been included. The feasibility and user experience were excellent. Mean speed during scenario 6, which displayed feedback with gradient color, attached to the world, with a speed relative to the player equal to his speed, and that disappeared over time, was significantly higher than other scenarios and control (p =0.003). Participants spent 80.98% of time above target speed during scenario 6. This scenario mixed the best combination of feedback characteristics to exceed the target walking speed (p=0.0058). Scenarios 5 and 6, which shared the same feedback characteristics for spatial anchoring (world-locked) and feedback speed (equal to the player speed), decreased the time to reach the target speed (p=0.019). Delivering multi-modal feedback has been recognized as more effective for improving motor performance. Therefore, our results showed that not all visual feedback had the same impact on performance. Further studies are required to test the weight of each feedback characteristic and their possible interactions inside each scenario. This study was registered in the ClinicalTrials.gov database (NCT04460833).

Simplified Virtual Reality System Can Be Used to Evaluate the Temporal Discrimination Ability in Softball Batting as in the Real Environment

Recently, virtual reality (VR) technology has developed rapidly and has increasingly come to be used in the sports field. VR technology ranges from large, highly immersive devices to simple devices such as smartphones, and the respective usefulness and shortcomings of different device types have been debated. Simple devices have advantages such as portability, but also provide only a weak sense of realism. It is important to understand the purpose and extent to which VR technologies can be used. Our purpose in this study was to briefly measure one of the cognitive-motor abilities used in softball batting: temporal discrimination ability in swing onset when a batter faces two types of balls thrown at different speeds. We investigated whether a simplified head-mounted display (HMD) system can evaluate such cognitive-motor ability to the same extent as in a real environment. Ten elite female softball batters swung at fastballs and slowballs randomly thrown by the same pitcher in both real and 3D VR environments, with the same range of trajectories. We then compared the temporal discrimination ability of swing onset analyzed by video analysis between environments. We found that the discrimination ability in VR is almost the same as in reality. In addition, questionnaire items on the VR system related to user experience and cybersickness showed overall promising responses. However, we also found that the system had some issues that need to be considered, such as leading to early swing onset and large variability in it. We discussed the usefulness and limitations of the VR system by combining the results for swing onset with the questionnaire responses. By understanding the characteristics of VR technology and using it as an efficient evaluation and training of players, the sports field can make significant progress.

Assessment of dual-tasking during a dynamic balance task using a smartphone app: a pilot study

[Purpose] To assess if the instrumented Timed Up and Go (iTUG) task score calculated with an iPhone application can detect gait changes under dual-tasking conditions. [Participants and Methods] Twenty participants (age 38.30 ± 12.54, 12 females) were asked to complete the TUG as a single task and under two dual-tasking conditions: 1) verbal fluency and 2) mental calculation. We used a smartphone, stopwatch, digital camera, and wearable sensor to calculate the dependent variables which included time, step count, gait speed, and iTUG score and, the dual-tasking cost (DTC) of those variables. We used Friedman analyses of variance and Wilcoxon tests for statistical analyses. [Results] the iTUG score, step count, gait speed, and the time measured by the stopwatch and wearable sensor differed significantly for all tasks, but the smartphone time did not. [Conclusion] We conclude that the iTUG score could be used as a sensitive measure for identifying gait changes under dual-tasking conditions. With the growing demands of telehealth, using technology as an objective tool for movement analysis is needed for clinicians and payers. Our findings demonstrate the potential value of the iTUG score to assess and track patient’s progress.