Locomotor skill acquisition in virtual reality shows sustained transfer to the real world

Visuospatial Skills Explain Differences in the Ability to Use Propulsion Biofeedback Post-stroke

BACKGROUND AND PURPOSE

Visual biofeedback can be used to help people post-stroke reduce biomechanical gait impairments. Using visual biofeedback engages an explicit, cognitively demanding motor learning process. Participants with better overall cognitive function are better able to use visual biofeedback to promote locomotor learning; however, which specific cognitive domains are responsible for this effect are unknown. We aimed to understand which cognitive domains were associated with performance during acquisition and immediate retention when using visual biofeedback to increase paretic propulsion in individuals post-stroke.

METHODS

Participants post-stroke completed cognitive testing, which provided scores for different cognitive domains, including executive function, immediate memory, visuospatial/constructional skills, language, attention, and delayed memory. Next, participants completed a single session of paretic propulsion biofeedback training, where we collected treadmill-walking data for 20 min with biofeedback and 2 min without biofeedback. We fit separate regression models to determine if cognitive domain scores, motor impairment (measured with the lower-extremity Fugl-Meyer), and gait speed could explain propulsion error and variability during biofeedback use and recall error during immediate retention.

RESULTS

Visuospatial/constructional skills and motor impairment best-explained propulsion error during biofeedback use (adjusted R 2  = 0.56, P = 0.0008), and attention best-explained performance variability (adjusted R 2  = 0.17, P = 0.048). Language skills best-explained recall error during immediate retention (adjusted R 2  = 0.37, P = 0.02).

DISCUSSION AND CONCLUSIONS

These results demonstrate that specific cognitive domain impairments explain variability in locomotor learning outcomes in individuals with chronic stroke. This suggests that with further investigation, specific cognitive impairment information may be useful to predict responsiveness to interventions and personalize training parameters to facilitate locomotor learning.

Effects of immersive virtual reality training on balance, gait and mobility in older adults: A systematic review and meta-analysis

OBJECTIVE

To examine whether immersive virtual reality (VR) can improve balance, gait, mobility and fear of falling in older people.

DATA SOURCES

MEDLINE, EMBASE, CINAHL, PsycINFO, ProQuest Central (Engineering and Computer Science) and reference lists of included articles.

STUDY SELECTION

Randomised controlled trials that administered immersive VR training and assessed balance, gait and mobility outcomes in older adults without neurological disorders (mean age ≥ 65). Primary outcomes were standing balance (e.g. postural sway), multi-item balance scales (e.g. Berg Balance Scale), gait (e.g. gait speed) and mobility (e.g. Timed Up and Go test). Secondary outcomes comprised measures of enjoyment, fear of falling, adherence (e.g. dropout rate), feasibility/usability and adverse effects (e.g. motion sickness).

RESULTS

Meta-analyses showed that immersive VR training significantly improved standing balance (SMD: 0.51, 95% CI: .15, 0.86, p = 0.005, I2 = 28% - 3 studies, n = 79) and performance on the Berg Balance Scale (MD: 2.36, 95% CI: 1.17, 3.56, p=0.0001, I2=0% - 4 studies, n = 190). No significant improvement in gait, mobility or fear of falling was found. Subgroup analyses revealed higher training doses (≥4.5 total hours) and VR interventions using non-head mounted displays were more likely to improve standing balance. No meta-analyses were conducted for enjoyment, adherence, feasibility/usability and adverse events.

CONCLUSIONS

The findings indicate immersive VR has beneficial effects on balance, but not gait, mobility or fear of falling. Further research is required to examine these outcomes in trials that also include quantitative measurements of enjoyment, adherence, clinical feasibility, usability and adverse effects.

Effects of Virtual Reality Interventions on the Parameters of Normal Labor: A Systematic Review and Meta-Analysis of Randomized Controlled Trials. A Meta-Analysis of Virtual Reality Interventions on the Parameters of Normal Labor

BACKGROUND

Clinical and experimental studies on virtual reality have shown that this easy-to-use and non-invasive method is a safe and effective strategy during normal labor.

AIM

This study aims to analyze the effects of virtual reality (VR) interventions on some of the parameters of normal labor.

DESIGN

Systematic review and meta-analysis.

METHOD

Higher Education Council National Thesis Center, Scopus, PubMed, Google Scholar, and Science Direct databases were systematically searched for randomized controlled trials that administered VR to the intervention group but not to the control group and were published through January 2022. RevMan software was used to analyze the meta-analysis data. Pain, anxiety, satisfaction, and the duration of the first and second stages of labor were assessed as outcomes of normal labor.

RESULTS

Seven randomized controlled trials, with a total of 756 women in total, met the inclusion criteria. Virtual reality interventions significantly reduced pain scores when cervical dilatation was ≤4 cm (MD = -0.43, 95% expansion here (CI [-0.65, -0.21], p < .001) and ≥9 cm (SMD = -1.91, 95% CI [-2.56, -1.26], p < .001). Anxiety scores significantly decreased (SMD = -1.08, 95% CI [-1.75, 0.41], p < .001), and childbirth satisfaction significantly increased (MD = 11.24, 95% CI [2.17, 20.30], p < .001) in the VR intervention groups. Finally, when compared to the control groups, the duration of the first stage of labor (SMD = -0.53, 95% CI [-0.83, -0.22], p < .01) and the second stage of labor (MD = -0.39, 95% CI [-0.76, -0.02], p = .001) were significantly decreased in the VR intervention groups.

CONCLUSIONS

Virtual reality interventions are effective methods to reduce pain, anxiety, and the duration of the first and second stages of labor and to increase satisfaction with normal labor.

Virtual training, real effects: a narrative review on sports performance enhancement through interventions in virtual reality

The present article reports a narrative review of intervention (i.e., training) studies using Virtual Reality (VR) in sports contexts. It provides a qualitative overview and narrative summary of such studies to clarify the potential benefits of VR technology for sports performance enhancement, to extract the main characteristics of the existing studies, and to inform and guide future research. Our literature search and review eventually resulted in 12 intervention studies with a pre vs. post design focused on different sports, including target and precision sports (archery, bowling, curling, darts, golf), bat/racquet and ball sports (baseball, table tennis), goal sports (football/soccer, basketball), martial arts (karate), and sport-unspecific processes such as bodily sensations and balancing. The samples investigated in the primary studies included novice, amateur, and expert athletes (total aggregated sample size N = 493). Many studies found statistically significant effects in relevant target skills following interventions in VR, often outperforming training effects in passive or active control conditions (e.g., using conventional training protocols). Therefore, interventions in VR (or extended reality) have the potential to elicit real effects in sports performance enhancement through training of motor and psychological skills and capabilities in athletes, including perception-action skills, strategic, tactical and decision-making, responding to unexpected events, and enhancing psychological resilience and mental performance under pressure. The neurocognitive mechanisms (e.g., visual search behavior, imagery), methodological aspects (e.g., adaptive training difficulty), and the issues of real-world transfer and generalizability via which these potential sports-performance-related improvements may occur are discussed. Finally, limitations of the present review, the included studies, the current state of the field in general as well as an outlook and future perspectives for research designs and directions are taken into consideration.

Movement kinematic and postural control differences when performing a visuomotor skill in real and virtual environments

Immersive technologies, like virtual and mixed reality, pose a novel challenge for our sensorimotor systems as they deliver simulated sensory inputs that may not match those of the natural environment. These include reduced fields of view, missing or inaccurate haptic information, and distortions of 3D space; differences that may impact the control of motor actions. For instance, reach-to-grasp movements without end-point haptic feedback are characterised by slower and more exaggerated movements. A general uncertainty about sensory input may also induce a more conscious form of movement control. We tested whether a more complex skill like golf putting was also characterized by more consciously controlled movement. In a repeated-measures design, kinematics of the putter swing and postural control were compared between (i) real-world putting, (ii) VR putting, and (iii) VR putting with haptic feedback from a real ball (i.e., mixed reality). Differences in putter swing were observed both between the real world and VR, and between VR conditions with and without haptic information. Further, clear differences in postural control emerged between real and virtual putting, with both VR conditions characterised by larger postural movements, which were more regular and less complex, suggesting a more conscious form of balance control. Conversely, participants actually reported less conscious awareness of their movements in VR. These findings highlight how fundamental movement differences may exist between virtual and natural environments, which may pose challenges for transfer of learning within applications to motor rehabilitation and sport.

Enhancement of awareness through feedback does not lead to interlimb transfer of obstacle crossing in virtual reality

Locomotor skill transfer is an essential feature of motor adaptation and represents the generalization of learned skills. We previously showed that gait adaptation after crossing virtual obstacles did not transfer to the untrained limb and suggested it may be due to missing feedback of performance. This study investigated whether providing feedback and an explicit goal during training would lead to transfer of adaptive skills to the untrained limb. Thirteen young adults crossed 50 virtual obstacles with one (trained) leg. Subsequently, they performed 50 trials with their other (transfer) leg upon notice about the side change. Visual feedback about crossing performance (toe clearance) was provided using a color scale. In addition, joint angles of the ankle, knee, and hip were calculated for the crossing legs. Toe clearance decreased with repeated obstacle crossing from 7.8 ± 2.7 cm to 4.6 ± 1.7 cm for the trained leg and from 6.8 ± 3.0 cm to 4.4 ± 2.0 cm (p < 0.05) for the transfer leg with similar adaptation rates between limbs. Toe clearance was significantly higher for the first trials of the transfer leg compared to the last trials of the training leg (p < 0.05). Furthermore, statistical parametric mapping revealed similar joint kinematics for trained and transfer legs in the initial training trials but differed in knee and hip joints when comparing the last trials of the trained leg with the first trials of the transfer leg. We concluded that locomotor skills acquired during a virtual obstacle crossing task are limb-specific and that enhanced awareness does not seem to improve interlimb transfer.

Narrowing the physiotherapy knowledge-practice gap: faculty training beyond the health sciences

Physiotherapists seek to improve client movement and promote function within an individual's unique environmental and social realities. Despite this intention, there is a well-noted knowledge-practice gap, that is, therapists generally lack sufficient foundational preparation to effectively navigate societal challenges impacting contemporary healthcare. As one step toward addressing the issue, we propose an educational solution targeting current and future physiotherapy faculty, whose responsibilities for entry-level course development and curriculum design substantially impact student readiness for clinical practice. We propose that physiotherapy faculty trained via postprofessional education in a non-biomedical field (e.g. psychology, education, and philosophy) will be uniquely prepared to provide students with tools for dealing with complex social issues facing their clients; critical analysis skills; statistical and technological training; and a deeper theoretical and philosophical understanding of practice. Taken together, such interdisciplinary tools could help address the knowledge-practice gap for physiotherapists and promote the ongoing evolution of the profession in concert with contemporary healthcare. Physiotherapists who pursue interdisciplinary studies may more deeply understand the challenges faced by clinicians and may be well-positioned to leverage knowledge and methods in another scientific discipline to expand and transform the scope of solutions to these challenges.

Haptic feedback intervention decreases the spatial margin when older adults walk through a narrow space

BACKGROUND

The ability to avoid obstacles efficiently and safely is important for older adults to prevent injuries from tripping and falling. It is important to find an optimal spatial margin between the body and an obstacle considering both safety and efficiency. One side of finding the optimal margin is to decrease the margin in terms of motor efficiency. In this study, we tested whether fingertip-contact intervention to obtain haptic feedback information to perceive the relationship between body and the environment could immediately improve spatial perception and collision avoidance behavior (an instantaneous effect).

METHODS

Twenty-seven older adults (12 males and 15 females) participated in the experiment. In the intervention of the fingertip-contact group, they lightly touched the edge of a door with both fingertips while walking. The test task before and after the intervention involved grasping a horizontal bar and passing through a narrow opening. As dependent variables, we measured the spatial margin and the collision rate.

RESULTS

The fingertip-contact group showed a significant decrease in the spatial margin after the intervention. On the other hand, there was no significant improvement in the collision rate after the intervention but rather a decrease only in the control group.

CONCLUSION

The results obtained in this study indicate that touching obstacles with the fingertips had an instantaneous effect, leading to efficient movement learning, although a possible side effect of an increased collision rated was also found. The proposed intervention might promote an efficiency-based strategy due to learning the spatial relationship between the body and the environment, and it may suppress the excessive avoidance of older adults.

Limited transfer and retention of locomotor adaptations from virtual reality obstacle avoidance to the physical world

Locomotor training based in virtual reality (VR) is promising for motor skill learning, with transfer of VR skills in turn required to benefit daily life locomotion. This study aimed to assess whether VR-adapted obstacle avoidance can be transferred to a physical obstacle and whether such transfer is retained after 1 week. Thirty-two young adults were randomly divided between two groups. A control group (CG) merely walked on a treadmill and an intervention group (IG) trained crossing 50 suddenly-appearing virtual obstacles. Both groups crossed three physical obstacles (transfer task) immediately after training (T1) and 1 week later (T2, transfer retention). Repeated practice in VR led to a decrease in toe clearance along with greater ankle plantarflexion and knee extension. IG participants crossed physical obstacles with a lower toe clearance compared to CG but revealed significantly higher values compared to the VR condition. VR adaptation was fully retained over 1 week. For physical obstacle avoidance there were differences between toe clearance of the third obstacle at T1 and the first obstacle at T2, indicating only partial transfer retention. We suggest that perception-action coupling, and thus sensorimotor coordination, may differ between VR and the physical world, potentially limiting retained transfer between conditions.

Effect of virtual reality training on standing balance in individuals with incomplete spinal cord injury

Recovery of balance ability during standing is one of the primary and essential aims of rehabilitative programs in individuals with incomplete spinal cord injury (iSCI). A sample of ten participants (mean age: 35.7 years, range: 25-63 years) with traumatic or non-traumatic iSCI (AIS grade C or D) and were able to stand with or without the support of an assistive device for a minimum of 2 min were recruited from the rehabilitation department of the Indian Spinal Injuries Centre, New Delhi, India. The participants received Virtual Reality (VR) based balance training for one hour, three times a week for four weeks on the Nintendo Wii gaming console. Participants were assessed three times: pre-intervention, post-intervention and follow-up assessment for the total ellipse area (TEA), total sway perimeter (TSP), sway range (anterior-posterior/medio-lateral (AP/ML)) and limits of stability (LOS). At post-intervention assessment, significant increases in comparison with pre-intervention scores was found in LOS (P=0.00), TEA with eyes open (EO) (P=0.00) and eyes closed (EC) (P=0.00), TSP with EO (P=0.00) and EC (P=0.00), sway range in AP direction (SD-AP) with EO (P=0.01) and EC (P=0.02) and sway range in ML direction (SD-ML) with EO (P=0.02) and EC (P=0.01). At follow-up assessment, a significant improvement in comparison to post intervention scores was found in TEA measured both in EO (P=0.01) and EC conditions (P=0.02), TSP measured with EO (P=0.01) and SD-ML both with EO (P=0.04) and EC (P=0.01). No significant changes were found in LOS (P=0.89), TSP measured with EC (P=0.38) and SD-AP both with EO (P=0.50) and EC (P=1). However, significant improvement was seen on comparing follow-up assessment scores with pre-intervention scores for all variables, such as LOS (P=0.00), TEA in EO (P=0.00) and EC (P=0.00), TSP with EO (P=0.00) and EC (P=0.00), SD-AP with EO (P=0.01) and EC (P=0.02) and SD-ML with EO (P=0.01) and EC (P=0.00). VR-based balance training intervention was able to elicit improvements in balance ability and maintain it during follow-up despite a small training dosage suggesting that it is a promising intervention for standing balance rehabilitation among individuals with iSCI. The VR-based balance training challenges elements of balance, which physical therapists may want to consider when designing a comprehensive rehabilitation program.

Clinical Trials Registry-India: CTRI/2018/12/016814.

Predicting individual differences in motor learning: a critical review

The ability to predict individual differences in motor learning has significant implications from both theoretical and applied perspectives. However, there is high variability in the methodological and analytical strategies employed as evidence for such predictions. Here, we critically examine the evidence for predictions of individual differences in motor learning by reviewing the literature from a 20-year period (2000-2020). Specifically, we examined four factors: (i) the predictor and predicted variables used, (ii) the strength of the prediction and associated sample size, (iii) the timescale over which the prediction was made, and (iv) the type of motor task used. Overall, the results highlight several issues that raise concerns about the quality of the evidence for such predictions. First, there was a large variation in both predictor and predicted variables, suggesting the presence of a large number of researcher degrees of freedom. Second, sample sizes tended to be small, and the strength of the correlation showed an inverse relation with sample size. Third, the timescale of most predictions was very short, mostly constrained to a single day. Last, most studies were largely restricted to two experimental paradigms - adaptation and sequence learning. Based on these issues, we highlight recommendations for future studies to improve the quality of evidence for predicting individual differences in motor learning.

Improved Walking Through an Aperture in a Virtual Environment Transfers to a Real Environment: Introduction of Enriched Feedback and Gradual Increase in Task Difficulty

Virtual reality (VR) could be used to set up a training protocol to improve one's collision-avoidance behavior. In our previous study, we developed a VR system for training older individuals to walk through an aperture in a manner that is both safe (i.e., no collision) and efficient (i.e., no exaggerated behavior to ensure collision avoidance). In the present study, we made several modifications to the VR system in terms of enriched feedback (vibratory stimulation for virtual collisions and the addition of positive feedback for successful trials) and gradual increase in task difficulty during training to strengthen the skill transfer. Nineteen older adults (74.4 ± 5.3 years of age) and 21 younger adults (25.1 ± 5.0 years of age) participated. They were randomly assigned to one of two training groups: the intervention group (older: n = 10; younger: n = 10) or the control group (older: n = 11; younger: n = 9). The experiment consisted of pre- and post-training tests in a real environment and training in a VR environment. During training, participants held a horizontal bar while stepping in place as if a VR image on the screen were moving in response to their stepping. Participants in the intervention group tried to pass a narrow aperture without collision while attempting to minimize their body rotation to avoid collision as much as possible. The criterion upon which the collision-avoidance behavior was regarded as successful became incrementally more demanding as participants successfully met the previous criterion. Participants in the control group passed through a very wide aperture, so that collision-avoidance behavior was unnecessary. A comparison between pre- and post-training test performances showed that, for both older and younger adults in the intervention group, the spatial margins became significantly smaller, while the success rate remained unchanged. For those in the control group, neither the spatial margin nor the success rate was improved. These results suggest that the three modifications made for the VR system contributed to improvement of the system and helped participants transfer the behavior learned from the VR environment to real walking.

Benefits of Virtual Reality Balance Training for Patients With Parkinson Disease: Systematic Review, Meta-analysis, and Meta-Regression of a Randomized Controlled Trial

BACKGROUND

Virtual reality (VR) balance training is increasingly being pursued in biomedical research, specifically with respect to investigating balance ability with VR. However, existing systematic reviews have found inconsistent conclusions about the efficacy of VR in improving balance in Parkinson disease (PD) patients.

OBJECTIVE

The goal of the research was to evaluate the impact of VR balance training on the balance ability of patients with PD.

METHODS

All major databases, including Web of Science, PubMed, Scopus, China National Knowledge Infrastructure, and Wanfang, were searched to identify all relevant studies published in English or Chinese since September 15, 2010. Two researchers independently conducted document retrieval, study selection, data extraction, and methodological quality evaluation.

RESULTS

A total of 16 randomized controlled trials were analyzed (n=583 patients with PD), with the methodological quality evaluation score ranging from 5 to 8 points. A random effects model was selected to combine effect sizes. Meta-analysis showed that the balance ability of PD was significantly improved after VR training compared with the control group (standardized mean difference [SMD] 2.127, 95% CI 1.202 to 3.052, P<.001, I²=95.1, df=15). It is worth noting that the intervention platform may be the main reason for heterogeneity. Meta regression analysis showed that no training program could predict the impact of VR training (P=.57 to .94) on PD balance ability. Subgroup result showed that a single training time of 0 to 20 minutes (SMD 6.446), 4 to 6 times per week (SMD 4.067), training for 3 to 5 weeks (SMD 62.478), training course reached more than 30 times (SMD 4.405), and 201 to 300 minutes per week (SMD 4.059) maybe have more benefit.

CONCLUSIONS

A systematic review and meta-analysis confirmed that VR balance training is a highly effective means to improve balance performance with large effects in PD. In addition, we preliminarily extracted dose-effect relationships for training volume, informing clinicians and practitioners to design effective VR balance training for balance ability. Further research is needed to reveal optimal dose-response relationships following VR balance training.

Effects of Endurance Training on Motor Signs of Parkinson's Disease: A Systematic Review and Meta-Analysis

BACKGROUND

Evidence has demonstrated that endurance training (ET) reduces the motor signs of Parkinson's disease (PD). However, there has not been a comprehensive meta-analysis of studies to date.

OBJECTIVE

The aim of this study was to compare the effect of ET versus nonactive and active control conditions on motor signs as assessed by either the Unified Parkinson's Disease Rating Scale part III (UPDRS-III) or Movement Disorder Society-UPDRS-III (MDS-UPDRS-III).

METHODS

A random-effect meta-analysis model using standardized mean differences (Hedges' g) determined treatment effects. Moderators (e.g., combined endurance and physical therapy training [CEPTT]) and meta-regressors (e.g., number of sessions) were used for sub-analyses. Methodological quality was assessed by the Physiotherapy Evidence Database.

RESULTS

Twenty-seven randomized controlled trials (RCTs) met inclusion criteria (1152 participants). ET is effective in decreasing UPDRS-III scores when compared with nonactive and active control conditions (g =  - 0.68 and g =  - 0.33, respectively). This decrease was greater (within- and between-groups average of - 8.0 and - 6.8 point reduction on UPDRS-III scores, respectively) than the moderate range of clinically important changes to UPDRS-III scores (- 4.5 to - 6.7 points) suggested for PD. Although considerable heterogeneity was observed between RCTs (I² = 74%), some moderators that increased the effect of ET on motor signs decreased the heterogeneity of the analyses, such as CEPTT (I² = 21%), intensity based on treadmill speed (I² = 0%), self-perceived exertion rate (I² = 33%), and studies composed of individuals with PD and freezing of gait (I² = 0%). Meta-regression did not produce significant relationships between ET dosage and UPDRS-III scores.

CONCLUSIONS

ET is effective in decreasing UPDRS-III scores. Questions remain about the dose-response relationship between ET and reduction in motor signs.

The Effects of Virtual Reality Nonphysical Mental Training on Coordination and Skill Transfer in Healthy Adults

CONTEXT

Mental training is a promising method to improve motor skills. However, transfer of these improvements to different skills or functional activities is still unclear. The purpose of this study was to investigate the effects of mental balance training programs on motor coordination and skill transfer.

DESIGN

Randomized controlled trial.

METHODS

Fifty-seven healthy adults (28 females and 29 males) aged between 18 and 25 years participated in this study. Participants were randomly assigned to 3 groups: virtual reality (VR) mental training group, conventional mental training group, and control group. The training program included action observation and motor imagery practice with balance exercise videos. The VR mental training group trained with a VR head-mounted display and the conventional mental training group trained with a nonimmersive computer monitor for 30 minutes, 3 days per week, for 4 weeks. Coordination skills were tested with 2 separate custom-made obstacle course tests (OCT-1 and OCT-2). OCT tests included crouching, turning, leaning, stepping over, changing direction, walking on various surfaces, or using repeated hand and arm movement tasks. OCT-1 was used to investigate the effects of mental exercises on coordination skills, and OCT-2 to investigate transfer effects for novel tasks. Test time (total and corrected) and error types (minor, major, and total) were recorded. Touching an obstacle without changing its position was classified as a minor error, and changing its position was a major error.

RESULTS

OCT-1 test time and number of errors significantly decreased in the VR mental training and conventional mental training groups, but not in the control group. The number of minor errors was only decreased in the VR mental training group. For OCT-2, total and corrected time were not significantly different between the groups. However, both training groups were significantly superior to the control group for all types of errors.

CONCLUSIONS

Our findings suggest that both training interventions can significantly improve coordination and skill transfer test results. In addition, VR mental training may have some advantages over conventional mental training. These findings are promising for the use of mental training for prevention and rehabilitation in special populations.

Conducting a VR Clinical Trial in the Era of COVID-19

The outbreak of severe acute respiratory syndrome coronavirus 2, also known as Coronavirus Disease 2019 (COVID-19) sparked a global public health pandemic that has impacted every aspect of daily life. Medical research was affected, and many clinical trials were halted to minimize COVID-19 transmission risk and spread while the world navigated this novel virus. Here we describe the relaunch of our virtual reality (VR) pilot clinical trial that uses an in-lab brain and body training program to promote brain health in mid-to-late life older adults, in the era of COVID-19. This case series includes five healthy female participants between 51 and 76 years of age, a subset of a larger VR pilot clinical trial that started pre-pandemic. We developed a revised study protocol based on the Center for Disease Control and World Health Organization guidelines to help manage the spread of COVID-19. Since the limited resumption of clinical trials at our institution in August 2020, we successfully completed over 200 in-lab virtual reality training sessions using our revised protocol. During this time, none of the five participants or three study staff reported any COVID-19 symptoms or reported a positive COVID-19 test. More than 40 voluntary COVID-19 tests were completed by our study staff over the last 6 months. All participants rated our safety protocol as very satisfied or extremely satisfied and that they would be very likely or extremely likely to participate in a VR clinical trial during the pandemic. Based on these findings, we suggest that continued VR clinical trial research during the COVID-19 pandemic is achievable and can be safely resumed if specific safety protocols are in place to mitigate the risk of exposure and spread of COVID-19.

Obstacle avoidance training in virtual environments leads to limb-specific locomotor adaptations but not to interlimb transfer in healthy young adults

Obstacle avoidance is one of the skills required in coping with challenging situations encountered during walking. This study examined adaptation in gait stability and its interlimb transfer in a virtual obstacle avoidance task. Twelve young adults walked on a treadmill while wearing a virtual reality headset with their body state represented in the virtual environment. At random times, but always at foot touchdown, 50 virtual obstacles of constant size appeared 0.8 m in front of the participant requiring a step over with the right leg. Early, mid and late adaptation phases were investigated by pooling data from trials 1-3, 24-26 and 48-50. One left-leg obstacle appearing after 50 right-leg trials was used to investigate interlimb transfer. Toe clearance and the anteroposterior margin of stability (MoS) at foot touchdown were calculated for the stepping leg. Toe clearance decreased over repeated practice between early and late phases from 0.13 ± 0.05 m to 0.09 ± 0.04 m (mean ± SD, p < 0.05). MoS increased from 0.05 ± 0.02 m to 0.08 ± 0.02 m (p < 0.05) between early and late phases, with no significant differences between mid and late phases. No differences were found in toe clearance and MoS between the practiced right leg for early phase and the single trial of the left leg. Obstacle avoidance during walking in a virtual environment stimulated adaptive gait improvements that were related in a nonlinear manner to practice dose, though such gait adaptations seemed to be limited in their transferability between limbs.

Feasibility of virtual reality behavior skills training for preservice clinicians

Effective training procedures include behavioral skills training (BST), which involves providing written and verbal instructions, modeling of the skill, rehearsal of the skill, and feedback on the performance. This training typically involves in vivo experience in which trainees and students are exposed to risks such as proximity to infectious disease, behavioral issues such as aggression, and errors in teaching performance. Conducting BST in a virtual reality (VR) context involving virtual individuals with problem behavior may be an effective means of mitigating these risks. The purpose of this study was to examine the feasibility of training students to conduct functional communication training (FCT) in a VR environment using BST. We trained 13 preservice college students to implement FCT for attention and escape functions. We found VR BST was effective at increasing correct steps performed of FCT to mastery criterion levels with all participants. Future researchers should examine generalization and maintenance of VR BST.

Effects of an external focus of attention and target occlusion on performance in virtual reality

The use of virtual reality as a training mechanism continues to gain popularity as equipment becomes more readily available. It is important to not only understand the relationship between virtual reality training and motor learning, but to understand the extent to which practice manipulations enhance performance in virtual reality. One common practice manipulation is adopting an external focus of attention, which has been shown to facilitate motor learning in a variety tasks. The purposes of the present study were to investigate the effectiveness of an external focus of attention and the effects of target occlusion times in virtual reality. Fifty-six participants performed a single-leg long jump during baseline, training, and retention and were randomly assigned to either an external or control group. During baseline and retention, all participants performed the task in both a virtual reality (VR) and real world (RW) environments. Training was all done in VR where participants were provided an external focus cue or no cue. Results revealed that individuals jumped significantly further in RW than VR in both baseline and retention (p < .001). During training, the external group jumped significantly further than control (p < .05). These results suggest that the adoption of an external focus improves performance during training. However, we did not see a benefit of an external focus in retention. These findings should be taken into consideration when using virtual reality as a training tool when performance must be transferred to a real world environment.

The Effect of Virtual Reality on the Ability to Perform Activities of Daily Living, Balance During Gait, and Motor Function in Parkinson Disease Patients: A Systematic Review and Meta-Analysis

OBJECTIVE

The study aimed to evaluate the effect of virtual reality on balance, motor function, gait, and the ability to perform activities of daily living in patients with Parkinson disease.

METHODS

We searched Cochran Central Register of Controlled Trials, Embase, PubMed, Wanfang Data, VIP Database, and China National Knowledge Infrastructure from their inception to June 2019. Two authors independently screened articles for inclusion, extracted data, and evaluated quality.

RESULTS

Twelve randomized clinical trials involving 360 patients were included. It demonstrated that virtual reality can improve balance, measured by the Berg Balance Scale (fixed model weighted mean difference = 2.28, 95% CI = 1.39 to 3.16, P < 0.00001); strengthen motor function, assessed by the Timed Up and Go test (fixed model weighted mean difference = -1.66, 95% CI = -2.74 to 0.58, P = 0.003); enhance gait ability, assessed by the 10-Meter Walk Test Time (fixed model weighted mean difference = 0.13, 95% CI = 0.02 to 0.24, P = 0.02) in patients with Parkinson disease. It also showed that virtual reality can improve individuals' ability to perform activities of daily living, assessed by modified Barthel Index (fixed model weighted mean difference = 2.93, 95% CI = 0.8 to 5.06, P = 0.007).

CONCLUSIONS

The findings suggest that virtual reality rehabilitation may be valuable in improving the balance, motor function, gait, and ability to perform activities of daily living in patients with Parkinson disease.

Training older adults with virtual reality use to improve collision-avoidance behavior when walking through an aperture

Many older adults perform collision-avoidance behavior either insufficiently (i.e., frequent collision) or inefficiently (i.e., exaggerated behavior to ensure collision-avoidance). The present study examined whether a training system using virtual reality (VR) simulation enhanced older adults' collision-avoidance behavior in response to a VR image of an aperture during real walking. Twenty-five (n = 13 intervention group and n = 12 control group) older individuals participated. During training, a VR image of walking through an aperture was projected onto a large screen. Participants in the intervention group tried to avoid virtual collision with the minimum body rotation required to walk on the spot through a variety of narrow apertures. Participants in the control group remained without body rotation while walking on the spot through a wide aperture. A comparison between pre-test and post-test performances in the real environment indicated that after the training, significantly smaller body rotation angles were observed in the intervention group. This suggests that the training led participants to modify their behavior to try to move efficiently during real walking. However, although not significant, collision rates also tended to be greater, suggesting that, at least for some participants, the modification required to avoid collision was too difficult. Transfer of the learned behavior using the VR environment to real walking is discussed.

The retention of fall-resisting behavior derived from treadmill slip-perturbation training in community-dwelling older adults

The purpose of this study was to determine whether and to what extent the immediate generalization of treadmill slip-perturbation training could be retained over 6 months to resist overground slip-induced falls. Four protocols (Tc: treadmill control; Tt: treadmill slip-perturbation training; Oc: overground control; Ot: overground slip-perturbation training) from two randomized controlled trials were compared in which two training protocols were executed with single-session repeated slip-perturbation training on the treadmill or overground context, while two control protocols were executed without repeated training. A total of 152 community-dwelling older adults (≥ 65 years) who were trained by one of the four protocols and tested by an overground slip in the initial session attended a retest session 6 months later. Falls were detected by a load cell. Data collected from motion analysis system and force plates were used to calculate stability. Tt group had no significant change in fall incidence from initial post-training test to retest. Tt group had significantly lower fall incidence (p < 0.05) and higher reactive stability (p < 0.05) than Tc group in retest. Tt group had significantly higher fall incidence (p < 0.05) and lower reactive stability (p < 0.01) than Ot group. The generalization of a single session of treadmill slip-perturbation training to overground slip resulted in inferior outcomes compared with overground slip-perturbation training (absolute retention), although the training generalization could be retained over 6 months (relative retention). Thus, treadmill slip-perturbation training could be more convenient to use if future dose-response studies indicate better or equal efficacy to overground slip-perturbation training.

Gait coordination in overground walking with a virtual reality avatar

Little information is currently available on interpersonal gait synchronization in overground walking. This is caused by difficulties in continuous gait monitoring over many steps while ensuring repeatability of experimental conditions. These challenges could be overcome by using immersive virtual reality (VR), assuming it offers ecological validity. To this end, this study provides some of the first evidence of gait coordination patterns for overground walking dyads in VR. Six subjects covered the total distance of 27 km while walking with a pacer. The pacer was either a real human subject or their anatomically and biomechanically representative VR avatar driven by an artificial intelligence algorithm. Side-by-side and front-to-back arrangements were tested without and with the instruction to synchronize steps. Little evidence of spontaneous gait coordination was found in both visual conditions, but persistent gait coordination patterns were found in the case of intentional synchronization. Front-to-back rather than side-by-side arrangement consistently yielded in the latter case higher mean synchronization strength index. Although the mean magnitude of synchronization strength index was overall comparable in both visual conditions when walking under the instruction to synchronize steps, quantitative and qualitative differences were found which might be associated with common limitations of VR solutions.

Influence on the user's emotional state of the graphic complexity level in virtual therapies based on a robot-assisted neuro-rehabilitation platform

BACKGROUND

In recent years, a remarkable trend in neurorehabilitation is the combination of conventional methods and emerging technologies, such as robotic platforms with virtual reality (VR), Serious Games (SG) and other types of sophisticated graphic interfaces. The aim of the present study is to evaluate the influence on the user's mental workload of the degree of graphic detail present in this kind of environments, comparing the experience of subjects working with two graphical environments with the same physical load but radically different graphic detail levels.

METHODS

The same therapy is performed by 52 healthy subjects in two totally different graphic environments, one rich in details and visual stimuli, and its schematic version focusing just in the target graphic elements. Autonomic Nervous System (ANS) activity, related to emotional state, is analyzed through the capture and processing of associated physiological signals. The SAM test is used to assess the subjective perception of the participants in order to establish a relationship with the calculated physiological parameters.

RESULTS

Indexes calculated from the ANS physiological signals show significant differences between the basal state and those corresponding to the performance of the therapies but do not allow discriminating between the effects of performing a therapy based on an environment rich in stimuli and an austere one. In the case of subjective perceptions, based on the results of the SAM test, the subjects perceive significant differences between the basal stage and the therapies, and also between each of the two graphic environments.

CONCLUSIONS

Users reflected that a graphic environment rich in detail was more pleasant and attractive than a schematic one. However, this is not reflected in values obtained from their physiological activity, which suggests that more research is needed about the online inference of the emotional state of the subject from the record of his physiological activity.

Transfer of motor skill between virtual reality viewed using a head-mounted display and conventional screen environments

BACKGROUND

Virtual reality viewed using a head-mounted display (HMD-VR) has the potential to be a useful tool for motor learning and rehabilitation. However, when developing tools for these purposes, it is important to design applications that will effectively transfer to the real world. Therefore, it is essential to understand whether motor skills transfer between HMD-VR and conventional screen-based environments and what factors predict transfer.

METHODS

We randomized 70 healthy participants into two groups. Both groups trained on a well-established measure of motor skill acquisition, the Sequential Visual Isometric Pinch Task (SVIPT), either in HMD-VR or in a conventional environment (i.e., computer screen). We then tested whether the motor skills transferred from HMD-VR to the computer screen, and vice versa. After the completion of the experiment, participants responded to questions relating to their presence in their respective training environment, age, gender, video game use, and previous HMD-VR experience. Using multivariate and univariate linear regression, we then examined whether any personal factors from the questionnaires predicted individual differences in motor skill transfer between environments.

RESULTS

Our results suggest that motor skill acquisition of this task occurs at the same rate in both HMD-VR and conventional screen environments. However, the motor skills acquired in HMD-VR did not transfer to the screen environment. While this decrease in motor skill performance when moving to the screen environment was not significantly predicted by self-reported factors, there were trends for correlations with presence and previous HMD-VR experience. Conversely, motor skills acquired in a conventional screen environment not only transferred but improved in HMD-VR, and this increase in motor skill performance could be predicted by self-reported factors of presence, gender, age and video game use.

CONCLUSIONS

These findings suggest that personal factors may predict who is likely to have better transfer of motor skill to and from HMD-VR. Future work should examine whether these and other predictors (i.e., additional personal factors such as immersive tendencies and task-specific factors such as fidelity or feedback) also apply to motor skill transfer from HMD-VR to more dynamic physical environments.

[New perspectives of motor rehabilitation of patients after focal brain lesions]

Rehabilitation of patients after focal brain lesions is one of the topical issues of modern medicine. Motor disorders are known to develop in more than 80% of survivors of stroke and traumatic brain injury and be one of the main causes of disability, which necessitates an active search for new effective techniques for correction of motor disorders. Modern rehabilitation includes both traditional techniques for recovery of patients with motor deficit (exercise therapy and physiotherapy) and botulinum therapy, kinesiotherapy, mechanotherapy, etc., which have been developed in recent years. Robotic technologies have been developed, improved, and implemented. Currently, due to progress in computerization, virtual reality-based rehabilitation of patients is of particular interest. The article reviews the key studies in this field. We describe various visualization methods and means of immersion in a virtual environment for recovery of upper and lower extremity function in patients with focal brain lesions. The study provides an assessment of the effectiveness and safety of various virtual reality-based rehabilitation programs in patients with motor disorders after stroke and traumatic brain injury.