Learning and transfer of complex motor skills in virtual reality: a perspective review

A 3-D interactive microbiology laboratory via virtual reality for enhancing practical skills

Virtual Reality (VR) laboratories are a new pedagogical approach to support psychomotor skills development in undergraduate programmes to achieve practical competency. VR laboratories are successfully used to carry out virtual experiments in science courses and for clinical skills training in professional courses. This paper describes the development and evaluation of a VR-based microbiology laboratory on Head-Mounted Display (HMD) for undergraduate students. Student and faculty perceptions and expectations were collected to incorporate into the laboratory design. An interactive 3-dimensional VR laboratory with a 360° view was developed simulating our physical laboratory setup. The laboratory environment was created using Unity with the (created) necessary assets and 3D models. The virtual laboratory was designed to replicate the physical laboratory environment as suggested by the students and faculty. In this VR laboratory, six microbiology experiments on Gram staining, bacterial streaking, bacterial motility, catalase test, oxidase test and biochemical tests were placed on the virtual platform. First-year biomedical science students were recruited to evaluate the VR laboratory. Students' perception of the virtual laboratory was positive and encouraging. About 70% of the students expressed they felt safe using the VR laboratory and that it was engaging. They felt that the VR laboratory provided an immersive learning experience. They appreciated that they could repeat each experiment multiple times without worrying about mistakes or mishaps. They could personalise their learning by concentrating on the specific experiments. Our in-house VR-based microbiology laboratory was later extended to other health professions programmes teaching microbiology.

Evaluating tactile feedback in addition to kinesthetic feedback for haptic shape rendering: a pilot study

In current virtual reality settings for motor skill training, only visual information is usually provided regarding the virtual objects the trainee interacts with. However, information gathered through cutaneous (tactile feedback) and muscle mechanoreceptors (kinesthetic feedback) regarding, e.g., object shape, is crucial to successfully interact with those objects. To provide this essential information, previous haptic interfaces have targeted to render either tactile or kinesthetic feedback while the effectiveness of multimodal tactile and kinesthetic feedback on the perception of the characteristics of virtual objects still remains largely unexplored. Here, we present the results from an experiment we conducted with sixteen participants to evaluate the effectiveness of multimodal tactile and kinesthetic feedback on shape perception. Using a within-subject design, participants were asked to reproduce virtual shapes after exploring them without visual feedback and with either congruent tactile and kinesthetic feedback or with only kinesthetic feedback. Tactile feedback was provided with a cable-driven platform mounted on the fingertip, while kinesthetic feedback was provided using a haptic glove. To measure the participants' ability to perceive and reproduce the rendered shapes, we measured the time participants spent exploring and reproducing the shapes and the error between the rendered and reproduced shapes after exploration. Furthermore, we assessed the participants' workload and motivation using well-established questionnaires. We found that concurrent tactile and kinesthetic feedback during shape exploration resulted in lower reproduction errors and longer reproduction times. The longer reproduction times for the combined condition may indicate that participants could learn the shapes better and, thus, were more careful when reproducing them. We did not find differences between conditions in the time spent exploring the shapes or the participants' workload and motivation. The lack of differences in workload between conditions could be attributed to the reported minimal-to-intermediate workload levels, suggesting that there was little room to further reduce the workload. Our work highlights the potential advantages of multimodal congruent tactile and kinesthetic feedback when interacting with tangible virtual objects with applications in virtual simulators for hands-on training applications.

Immersive virtual reality-based rehabilitation for subacute stroke: a randomized controlled trial

OBJECTIVE

Few effective treatments improve upper extremity (UE) function after stroke. Immersive virtual reality (imVR) is a novel and promising strategy for stroke UE recovery. We assessed the extent to which imVR-based UE rehabilitation can augment conventional treatment and explored changes in brain functional connectivity (FC) that were related to the rehabilitation.

METHODS

An assessor-blinded, parallel-group randomized controlled trial was performed with 40 subjects randomly assigned to either imVR or Control group (1:1 allocation), each receiving rehabilitation 5 times per week for 3 weeks. Subjects in the imVR received both imVR and conventional rehabilitation, while those in the Control received conventional rehabilitation only. Our primary and secondary outcomes were the Fugl-Meyer assessment's upper extremity subscale (FMA-UE) and the Barthel Index (BI), respectively. Both intention-to-treat (ITT) and per-protocol (PP) analyses were performed to assess the effectiveness of the trial. For both the FMA-UE/BI, a one-way analysis of covariance (ANCOVA) model was used, with the FMA-UE/BI at post-intervention or at follow-up, respectively, as the dependent variable, the two groups as the independent variable, baseline FMA-UE/BI, age, sex, site, time since onset, hypertension and diabetes as covariates.

RESULTS

Both ITT and PP analyses demonstrated the effectiveness of imVR-based rehabilitation. The FMA-UE score was greater in the imVR compared with the Control at the post-intervention (mean difference: 9.1 (95% CI 1.6, 16.6); P = 0.019) and follow-up (mean difference:11.5 (95% CI 1.9, 21.0); P = 0.020). The results were consistent for BI scores. Moreover, brain FC analysis found that the motor function improvements were associated with a change in degree in ipsilesional premotor cortex and ipsilesional dorsolateral prefrontal cortex immediately following the intervention and in ipsilesional visual region and ipsilesional middle frontal gyrus after the 12-week follow-up.

CONCLUSIONS

ImVR-based rehabilitation is an effective tool that can improve the recovery of UE functional capabilities of subacute stroke patients when added to standard care. These improvements were associated with distinctive brain changes at two post-stroke timepoints. The study results will benefit future patients with stroke and provide evidence for a promising new method of stroke rehabilitation.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: NCT03086889.

Sensory manipulation as a countermeasure to robot teleoperation delays: system and evidence

In the realm of robotics and automation, robot teleoperation, which facilitates human-machine interaction in distant or hazardous settings, has surged in significance. A persistent issue in this domain is the delays between command issuance and action execution, causing negative repercussions on operator situational awareness, performance, and cognitive load. These delays, particularly in long-distance operations, are difficult to mitigate even with the most advanced computing advancements. Current solutions mainly revolve around machine-based adjustments to combat these delays. However, a notable lacuna remains in harnessing human perceptions for an enhanced subjective teleoperation experience. This paper introduces a novel approach of sensory manipulation for induced human adaptation in delayed teleoperation. Drawing from motor learning and rehabilitation principles, it is posited that strategic sensory manipulation, via altered sensory stimuli, can mitigate the subjective feeling of these delays. The focus is not on introducing new skills or adapting to novel conditions; rather, it leverages prior motor coordination experience in the context of delays. The objective is to reduce the need for extensive training or sophisticated automation designs. A human-centered experiment involving 41 participants was conducted to examine the effects of modified haptic cues in teleoperations with delays. These cues were generated from high-fidelity physics engines using parameters from robot-end sensors or physics engine simulations. The results underscored several benefits, notably the considerable reduction in task time and enhanced user perceptions about visual delays. Real-time haptic feedback, or the anchoring method, emerged as a significant contributor to these benefits, showcasing reduced cognitive load, bolstered self-confidence, and minimized frustration. Beyond the prevalent methods of automation design and training, this research underscores induced human adaptation as a pivotal avenue in robot teleoperation. It seeks to enhance teleoperation efficacy through rapid human adaptation, offering insights beyond just optimizing robotic systems for delay compensations.

Individual differences in children's movement variability in a virtual reality playground task

Children's movements are highly complex, and thus require measurements that capture various gross motor strategies. This study examined whether aspects of individual differences in children's gross motor movement patterns could be captured in virtual reality (VR) and how motor movements could be conceptualized through freezing-freeing patterns of degrees of freedom. To this end, a three-minute VR scenario was developed for children to freely explore, play, and move around without further instructions, and their movement strategies were simultaneously captured by a non-invasive inertial motion capture system. Sixty-four children aged 7-10 (boys: n = 37, girls: n = 27) participated. The results of correlational and principal component analysis (PCA) on measures of variability of upper extremities indicated significant relationships between nearly all measures (r = 0.31-0.69, p < 0.05). Similarly, a PCA on variability from joint movements in the lower extremities indicated relatively high intercorrelations (r = 0.31-0.71, p < 0.01). A pattern of four different variability profiles was indicated in the interrelationship between the upper and lower body. These findings emphasize the value of using innovative measurements and whole-body motion capture to disentangle individual differences in children's movement variability in product- and process-oriented assessments of gross motor competence.

Comparing eye-hand coordination between controller-mediated virtual reality, and a real-world object interaction task

Virtual reality (VR) technology has advanced significantly in recent years, with many potential applications. However, it is unclear how well VR simulations mimic real-world experiences, particularly in terms of eye-hand coordination. This study compares eye-hand coordination from a previously validated real-world object interaction task to the same task re-created in controller-mediated VR. We recorded eye and body movements and segmented participants' gaze data using the movement data. In the real-world condition, participants wore a head-mounted eye tracker and motion capture markers and moved a pasta box into and out of a set of shelves. In the VR condition, participants wore a VR headset and moved a virtual box using handheld controllers. Unsurprisingly, VR participants took longer to complete the task. Before picking up or dropping off the box, participants in the real world visually fixated the box about half a second before their hand arrived at the area of action. This 500-ms minimum fixation time before the hand arrived was preserved in VR. Real-world participants disengaged their eyes from the box almost immediately after their hand initiated or terminated the interaction, but VR participants stayed fixated on the box for much longer after it was picked up or dropped off. We speculate that the limited haptic feedback during object interactions in VR forces users to maintain visual fixation on objects longer than in the real world, altering eye-hand coordination. These findings suggest that current VR technology does not replicate real-world experience in terms of eye-hand coordination.

Task integration in complex, bimanual sequence learning tasks

Sequence learning and multitasking studies have largely focused on simple motor skills, which cannot be directly transferred to the plethora of complex skills found outside of laboratory conditions. Established theories e.g. for bimanual tasks and task integration thus have to be reassessed in the context of complex motor skills. We hypothesize that under more complex conditions, task integration facilitates motor learning, impedes or suppresses effector-specific learning and can still be observed despite partial secondary task interference. We used the Ξ-apparatus to assess the learning success of six groups in a bimanual dual-task, in which we manipulated the degree of possible integration between the right-hand and the left-hand sequences. We could show that task integration positively influences the learning of these complex, bimanual skills. However, the integration impedes but not fully suppresses effector-specific learning, as we could measure reduced hand-specific learning. Task integration improves learning despite the disruptive effect of partial secondary task interference, but its mitigating effect is only effective to some extent. Overall, the results suggest that previous insights on sequential motor learning and task integration can largely also be applied to complex motor skills.

Effects of color cues on eye-hand coordination training with a mirror drawing task in virtual environment

Mirror drawing is a motor learning task that is used to evaluate and improve eye-hand coordination of users and can be implemented in immersive Virtual Reality (VR) Head-Mounted Displays (HMDs) for training purposes. In this paper, we investigated the effect of color cues on user motor performance in a mirror-drawing task between Virtual Environment (VE) and Real World (RW), with three different colors. We conducted a 5-day user study with twelve participants. The results showed that the participants made fewer errors in RW compared to VR, except for pre-training, which indicated that hardware and software limitations have detrimental effects on the motor learning of the participants across different realities. Furthermore, participants made fewer errors with the colors close to green, which is usually associated with serenity, contentment, and relaxation. According to our findings, VR headsets can be used to evaluate participants' eye-hand coordination in mirror drawing tasks to evaluate the motor-learning of participants. VE and RW training applications could benefit from our findings in order to enhance their effectiveness.

Anodal cerebellar t-DCS impacts skill learning and transfer on a robotic surgery training task

The cerebellum has demonstrated a critical role during adaptation in motor learning. However, the extent to which it can contribute to the skill acquisition of complex real-world tasks remains unclear. One particularly challenging application in terms of motor activities is robotic surgery, which requires surgeons to complete complex multidimensional visuomotor tasks through a remotely operated robot. Given the need for high skill proficiency and the lack of haptic feedback, there is a pressing need for understanding and improving skill development. We investigated the effect of cerebellar transcranial direct current stimulation applied during the execution of a robotic surgery training task. Study participants received either real or sham stimulation while performing a needle driving task in a virtual (simulated) and a real-world (actual surgical robot) setting. We found that cerebellar stimulation significantly improved performance compared to sham stimulation at fast (more demanding) execution speeds in both virtual and real-world training settings. Furthermore, participants that received cerebellar stimulation more effectively transferred the skills they acquired during virtual training to the real world. Our findings underline the potential of non-invasive brain stimulation to enhance skill learning and transfer in real-world relevant tasks and, more broadly, its potential for improving complex motor learning.

Distinct clusters of movement entropy in children's exploration of a virtual reality balance beam

Although assessing motor competence is vital to advancing current understandings of motor development and its significance in various fields, no consensus exists on how the construct should be operationalised and measured. Existing approaches to assessing motor competence in children typically involve applying qualitative and/or quantitative scoring procedures in which children's performance is evaluated according to certain levels of assessment-specific task performance dependent upon predefined sets of instructions and procedures. Building upon ecological dynamics as a framework, different levels of motor competence can be identified in children's attempts to coordinate their degrees of freedom while trying to complete the interactive task and environmental constraints. Given the dynamic, nonlinear features of that coordinating process, assessments need to consider the inherit structure of inter- and intra-individual variability in patterns of movement. Against that background, we investigated 7-10-year-old children's (n = 58) whole-body joint kinematics as they freely explored a balance beam in a virtual reality playground. Specifically, we used exploratory cluster analysis to examine the discriminatory capability of utilising joint-specific sample entropy as a window into individual differences in movement coordination that emerged from children's exploration of the constraints embedded in the virtual task. Among the results, three clusters of children with distinct profiles of movement variability emerged, all of which showed heterogeneous levels of repeatability in joint movements in combination with the level of spatiotemporal exploration on the balance beam that could not be explained by between-cluster differences in age and gender distributions. Those findings suggest that entropy from whole-body movements can be used to cluster children into distinct groups with different profiles regarding the structure of movement variability, which can inform new understandings and the development of gross motor competence assessments for children.

The Influence of Multisensory Input On Voice Perception and Production Using Immersive Virtual Reality

OBJECTIVES

The purpose was to examine the influence of auditory vs visual vs combined audiovisual input on perception and production of one's own voice, using immersive virtual reality technology.

METHODS

Thirty-one vocally healthy men and women were investigated under 18 sensory input conditions, using immersive virtual reality technology. Conditions included two auditory rooms with varying reverberation times, two visual rooms with varying volumes, and the combination of audiovisual conditions. All conditions were repeated with and without background noise. Speech tasks included counting, sustained vowel phonation, an all-voiced sentence from the Consensus Auditory-Perceptual Evaluation of Voice, and the first sentence from the Rainbow Passage, randomly ordered. Perception outcome measures were participants' self-reported perceptions of their vocal loudness, vocal effort, and vocal comfort in speech. Production outcome measures were sound pressure level (SPL) and spectral moments (spectral mean and standard deviation in Hz, skewness, and kurtosis). Statistical analyses used self-reported vocal effort, vocal loudness, and vocal comfort in percent (0 = "not at all," 100 = extremely), SPL in dB, and spectral moments in Hz. The reference level was a baseline audiovisual deprivation condition.

RESULTS

Results suggested (i) increased self-perceived vocal loudness and effort, and decreased comfort, with increasing room volume, speaker-to-listener distance, audiovisual input, and background noise, and (ii) increased SPL and fluctuations in spectral moments across conditions.

CONCLUSIONS

Not only auditory, but also visual and audiovisual input influenced voice perception and production in ways that have not been previously documented. Findings contribute to the basic science understanding the role of visual, audiovisual and auditory input in voice perception and production, and also to models of voice training and therapy. The findings also set the foundation for the use of virtual reality in voice and speech training, as a potentially power solution to the generalization problem.

Bill-EVR: An Embodied Virtual Reality Framework for Reward-and-Error-Based Motor Rehab-Learning

VR rehabilitation is an established field by now, however, it often refers to computer screen-based interactive rehabilitation activities. In recent years, there was an increased use of VR-headsets, which can provide an immersive virtual environment for real-world tasks, but they are lacking any physical interaction with the task objects and any proprioceptive feedback. Here, we focus on Embodied Virtual Reality (EVR), an emerging field where not only the visual input via VR-headset but also the haptic feedback is physically correct. This happens because subjects interact with physical objects that are veridically aligned in Virtual Reality. This technology lets us manipulate motor performance and motor learning through visual feedback perturbations. Bill-EVR is a framework that allows interventions in the performance of real-world tasks, such as playing pool billiard, engaging end-users in motivating life-like situations to trigger motor (re)learning - subjects see in VR and handle the real-world cue stick, the pool table and shoot physical balls. Specifically, we developed our platform to isolate and evaluate different mechanisms of motor learning to investigate its two main components, error-based and reward-based motor adaptation. This understanding can provide insights for improvements in neurorehabilitation: indeed, reward-based mechanisms are putatively impaired by degradation of the dopaminergic system, such as in Parkinson's disease, while error-based mechanisms are essential for recovering from stroke-induced movement errors. Due to its fully customisable features, our EVR framework can be used to facilitate the improvement of several conditions, providing a valid extension of VR-based implementations and constituting a motor learning tool that can be completely tailored to the individual needs of patients.

Intelligence, motoric and psychological outcomes in children from different ART treatments: a systematic review and meta-analysis

BACKGROUND

Subtle abnormalities in children's intelligence, motor skills, and psychology from various assisted reproductive treatments (ARTs) might be underdiagnosed. Understanding the prognosis of intelligence, motor skills, and psychology in children from ART would provide parents with reasonable expectations and enable them to plan relevant support to achieve the optimum potential in ART children.

METHODS

We searched PubMed, EMBASE, Ovid, Google Scholar, and Scopus databases until April 13, 2021, to identify relevant studies. Thirty-four studies met the inclusion and exclusion criteria. The meta-analysis employed a standardized mean difference model. The outcome of this study is to compare intelligence quotient (IQ), motoric ability, and behavioral problems between all ARTs, in vitro fertilization (IVF), intracytoplasmic sperm injection (ICSI) to naturally conceived (NC) children. Subdomains of intelligence based on the Cattell, Horn, and Carroll Model (CHC Model) of cognitive architecture, including fluid reasoning, short-term and working memory, processing speed, visual-spatial ability, long-term memory retrieval, and crystalized intelligence (knowledge), were evaluated and summarized in details. Motor skill was stratified into two domains: gross motoric and fine motoric. Behavioral problem was categorized as externalizing and internalizing behavior.

RESULTS

Meta-analysis showed that verbal intelligence score in IVF toddlers is significantly lower than NC toddlers (p = 0.02); conversely, ICSI toddlers scored significantly higher verbal intelligence score compared to NC toddlers (p = 0.005). Toddlers born after ART had significantly lower non-verbal intelligence score (p = 0.047). IVF toddlers scored significantly lower fine motor score (p = 0.01) compared to naturally conceived toddlers. Based on parent's CBCL, NC toddlers had higher total (p = 0.01) and externalizing behavior (p = 0.001) scores  compared to ART toddlers. Evaluation of full scale IQ and all domains of intelligence in preschool and primary school children revealed that no significant differences exist between ART and NC children. Based on preschool and primary school parents' CBCL, IVF children had significantly lower externalizing behavior score compared to NC children (p = 0.04). Meta-analyses of studies on young adolescents revealed that ART young adolescents scored higher academically than their NC counterparts, including on mathematics (p < 0.00001) and reading or language (p < 0.00001).

CONCLUSIONS

Despite differences in certain aspects, this finding suggests that ART is unlikely to cause negative impacts on children's neurodevelopment.

Virtual reality rehabilitation program on executive functions of children with specific learning disorders: a pilot study

Background

The application of Virtual Reality (VR) in the field of rehabilitation has been widely studied, because it has already proven to be an effective intervention for a variety of physical and cognitive conditions. Nevertheless, its application in pediatric rehabilitation is more recent. This pilot study aims to examine whether a VR-rehabilitation program may have positive effects on the Executive Functions (EFs) of children with Specific Learning Disorders (SLD).

Materials and methods

Twenty-four children with diagnosis of SLD participated to the study (range 7-11 years) and performed the VR-training across 6 weeks in the CARE Lab, that was designed with appropriate structural measures and ad hoc fittings, to hide the sophisticated technology necessary to allow the child to experience a rehabilitative setting with recreational and semi-immersive features. Children were evaluated across three main time-points: T0, assessment of cognitive level and EFs immediately before the start of the intervention; T1, assessment of EFs immediately after the end of VR intervention; T2, follow-up of EFs after 6 months from the end of the VR intervention. The rehabilitation programs were customized according to clinical needs and/or single patient's characteristics, proposing different games with variable complexity levels.

Results

Results showed that scores for visual attention, inhibition, flexibility, and planning abilities were significantly higher than before the intervention, and the most part of these ameliorations were maintained after 6 months.

Conclusion

These findings provide important inputs for the development of new innovative rehabilitation interventions for children with SLD that must be founded in ecological and evidence-based approaches.

Efficacy of integrating a semi-immersive virtual device in the HABIT-ILE intervention for children with unilateral cerebral palsy: a non-inferiority randomized controlled trial

BACKGROUND

The implementation of virtual devices can facilitate the role of therapists (e.g., patient motivation, intensity of practice) to improve the effectiveness of treatment for children with cerebral palsy. Among existing therapeutic devices, none has been specifically designed to promote the application of principles underlying evidence-based motor skill learning interventions. Consequently, evidence is lacking regarding the effectiveness of virtual-based sessions in motor function rehabilitation with respect to promoting the transfer of motor improvements into daily life activities. We tested the effectiveness of implementing a recently developed virtual device (REAtouch®), specifically designed to enable the application of therapeutic motor skill learning principles, during a Hand Arm Bimanual Intensive Therapy Including Lower Extremities (HABIT-ILE) intervention.

METHODS

Forty children with unilateral cerebral palsy (5-18 years; MACS I-III; GMFCS I-II) were randomly assigned to a control group or a "REAtouch®" experimental group for a 90-h HABIT-ILE day-camp intervention (two weeks). Children in the REAtouch® group spent nearly half of their one-on-one therapeutic time using the REAtouch®. Participants underwent three testing sessions: the week before (T1), after intervention (T2), and at three months follow-up (T3). The primary outcome was the Assisting Hand Assessment (T3-T1; blinded). Secondary outcomes measured uni-bimanual hand function, stereognosis, gait endurance, daily life abilities, and functional goals. Accelerometers and a manual report of daily activities served to document therapeutic dosage and treatment characteristics. We used one-way RMANOVA to compare the efficacies of the two interventions, and non-inferiority analyses to contrast changes in the "REAtouch®" group versus the "HABIT-ILE" control group.

RESULTS

We found significant improvements in both groups for most of the outcome measures (p < 0.05). There was significant non-inferiority of changes in the REAtouch® group for upper extremities motor function, functional goals attainment, and abilities in daily life activities (p < 0.05).

CONCLUSIONS

Use of the REAtouch® device during HABIT-ILE showed non-inferior efficacy compared to the conventional evidence-based HABIT-ILE intervention in children with unilateral cerebral palsy. This study demonstrates the feasibility of using this virtual device in a high dosage camp model, and establishes the possibility of applying the therapeutic principles of motor skill learning during specifically designed virtual-based sessions.

TRIAL REGISTRATION

Trial registration number: NCT03930836-Registration date on the International Clinical Trials Registry Platform (ICTRP): June 21th, 2018; Registration date on NIH Clinical Trials Registry: April 29th, 2019. First patient enrollment: July 3rd, 2018.

A systematic review and meta-analysis on the effect of virtual reality-based rehabilitation for people with Parkinson's disease

BACKGROUND

Virtual reality (VR) is a promising solution for individuals with Parkinson's disease (PD) who experience symptoms that affect their daily activities and independence. Through VR-based rehabilitation, patients can improve their motor skills in a safe and stress-free environment, making it an attractive alternative to traditional in-person rehabilitation during the COVID-19 pandemic. This study aimed to provide the most recent and convincing evidence on the rehabilitative effects of VR technology compared with conventional treatments.

METHODS

Two investigators systematically searched Embase, MEDLINE, CINAHL, PEDro, and the Cochrane Library from their inception until May 31, 2022, to identify randomized controlled trials (RCTs) comparing the effectiveness of VR training with that of conventional treatment for patients with PD. Studies were selected based on the patient, intervention, comparator, and outcome criteria and assessed for the risk of bias using the Cochrane tool. Meta-analysis was conducted by pooling mean differences with 95% confidence intervals.

RESULTS

A total of 14 RCTs, involving 524 participants, were included in the meta-analysis. The results indicated that VR-based rehabilitation significantly improved balance function, as measured using the Berg balance scale (BBS) and activities-specific balance confidence. However, no statistically significant differences in gait ability, activities of daily living, motor function, and quality of life were observed between the experimental and control groups. Subgroup analysis revealed that combination therapy affected heterogeneity in the BBS analysis. Meta-regression analysis demonstrated a significant positive relationship, indicating that more recent studies have shown greater improvements in balance function.

CONCLUSION

This study's findings suggest that VR-based rehabilitation is a promising intervention for improving balance function in patients for PD compared with conventional treatment, and recent research supports its efficacy. However, future research should focus on conducting long-term follow-up studies and developing standardized protocols to comprehensively establish this intervention's potential benefits.

Perception and knowledge of learners about the use of 3D technologies in manual therapy education - a qualitative study

OBJECTIVES

Manual therapy is a specific hands-on approach used and taught by various professions such as physiotherapy and osteopathy. The current paradigm of teaching manual therapy incorporates the traditional 'See one, do one, teach one' approach. However, this 'teacher centred' approach may not enable learners to develop the complex clinical skills of manual therapy. In this context, 3D technologies such as virtual reality may facilitate the teaching and learning of manual therapy. Hence the aim of the current study was to investigate the perception, knowledge and attitude of manual therapy learners about the use of 3D technologies in manual therapy education.

METHODS

An exploratory qualitative research design using semi-structured interviews was used in this study. A total of ten manual therapy (5 physiotherapy and 5 osteopathic) students (mean age = 32; 80% female) enrolled in an appropriate physiotherapy or osteopathic degree provided by a New Zealand recognized institution (e.g., university or polytechnic) participated in this study. Data saturation was achieved after 10 interviews (average duration: 35 min) that provided thick data. A thematic analysis was used for data analysis.

RESULTS

Six factors were identified which appeared to influence participants' perception of role of technology in manual therapy education. These were (1) the sufficiency of current teaching method; (2) evolution as a learner (a novice to an expert); (3) need for objectivity; (4) tutor feedback; (5) knowledge and (6) barriers and enablers. These six factors influenced the participants' perception about the role of 3D technologies in manual therapy education with participants evidently taking two distinct/polarized positions ('no role' (techstatic) versus a 'complete role' (techsavvy)).

CONCLUSION

Although 3D technology may not replace face-to-face teaching, it may be used to complement the traditional approach of learning/teaching to facilitate the learning of complex skills according to the perceptions of manual therapy learners in our study. The advantage of such an approach is an area of future research.

Virtual Reality for Upper Extremity Rehabilitation-A Prospective Pilot Study

Applications related to virtual reality are a rapidly growing area. Thus, these technologies are also increasingly used in the field of medicine and rehabilitation. The primary objective of this prospective pilot study was to investigate the feasibility, user experience and acceptance of a virtual-reality-based system for upper extremity rehabilitation. The study was conducted as a single-center trial over 16 weeks. The eligibility criteria included rehabilitants with upper extremity injuries of at least 18 years of age who were fluent in spoken and written German. After detailed instruction, each participant was asked to complete daily 30 min exercises over 15 training sessions with the virtual reality system consisting of three different training modules. Outcomes were assessed pre-study and post-study using standardized clinical measures. In addition, qualitative interviews with rehabilitants as well as therapists regarding user experience and acceptance were conducted. Six participants were recruited for the pilot study, of which five underwent virtual-reality-based rehabilitation. Overall, the clinical measures showed a positive tendency over the course of the study, even if the results were not significant. Furthermore, the virtual-reality-based training was well accepted by the participants as well as therapists. Given these findings, it will be beneficial to evaluate virtual reality for rehabilitation in further research.

Oromotor Nonverbal Performance and Speech Motor Control: Theory and Review of Empirical Evidence

This position paper offers a perspective on the long-standing debate concerning the role of oromotor, nonverbal gestures in understanding typical and disordered speech motor control secondary to neurological disease. Oromotor nonverbal tasks are employed routinely in clinical and research settings, but a coherent rationale for their use is needed. The use of oromotor nonverbal performance to diagnose disease or dysarthria type, versus specific aspects of speech production deficits that contribute to loss of speech intelligibility, is argued to be an important part of the debate. Framing these issues are two models of speech motor control, the Integrative Model (IM) and Task-Dependent Model (TDM), which yield contrasting predictions of the relationship between oromotor nonverbal performance and speech motor control. Theoretical and empirical literature on task specificity in limb, hand, and eye motor control is reviewed to demonstrate its relevance to speech motor control. The IM rejects task specificity in speech motor control, whereas the TDM is defined by it. The theoretical claim of the IM proponents that the TDM requires a special, dedicated neural mechanism for speech production is rejected. Based on theoretical and empirical information, the utility of oromotor nonverbal tasks as a window into speech motor control is questionable.

An analysis of clinical outcomes and essential parameters for designing effective games for upper limb rehabilitation: A scoping review

Background and Aims

Upper limb disabilities are one of the most common disabilities among different groups of people who always need rehabilitation. One of the important methods in helping to carry out efficient rehabilitation processes and exercises is the use of games. The aim of this study is to identify the parameters necessary to design a successful rehabilitation game and the outcomes of using these games in upper limb disabilities rehabilitation.

Methods

This scoping review was conducted by searching the Web of Science, PubMed, and Scopus. The eligibility criteria were: any form of game-based upper limb rehabilitation, published in a peer-reviewed journal, published in English, and not include articles that did not focus upper limb disabilities rehabilitation games, review, meta-analysis, or conference papers. Analysis of collected data was done using descriptive statistics (frequency and percentage).

Results

The search strategy retrieved 537 relevant articles. Finally, after removing irrelevant and repetitive articles, 21 articles were included in this study. Among the six categories of diseases or complications of upper limb disabilities, games were mostly designed for stroke patients. Smart wearables, robots and telerehabilitation were three technologies that were used for rehabilitation along with games. Sports and shooters were the most used games for upper limb disability rehabilitation. Among 99 necessary parameters for designing and implementing a successful rehabilitation game in ten categories. "Increasing the patient's motivation to perform rehabilitation exercises", "Game difficulty levels", "Enjoying and the attractiveness of the game for patients", and "Providing positive or negative audiovisual feedback" were the most important parameters. "Improvement in musculoskeletal performance" and "Increasing users' enjoyment/joy of therapeutic exercises and their motivation to perform these exercises" were the most important positive outcomes, and "Mild discomfort such as nausea and dizziness when using games" was the only negative outcome.

Conclusions

The successful design of a game according to the parameters identified in the present study can lead to an increase in the positive outcomes of using games in the rehabilitation of disabilities. The study results indicate that upper limb therapeutic exercise augmented with virtual reality games may be highly effective in enhancing motor rehabilitation outcomes.

Virtual reality-based gait rehabilitation intervention for stroke individuals: a scoping review

Virtual reality (VR)-based rehabilitation is rapidly gaining interest and has been shown to be an intervention to facilitate motor learning in balance and gait rehabilitation. A review of the current literature is needed to provide an overview of the current state of knowledge of VR-based gait physiotherapy for stroke patients. A systematic literature search was performed in PubMed and Scopus. Search terms included: "virtual reality," "stroke," "gait," and "physical therapy." Articles published in a peer-reviewed journal between 2017 and 2021 were considered. The intervention was mainly related to the use of VR as a therapeutic modality, and the outcome was gait performance. The initial search identified 329 articles. After an eligibility review, 13 articles that met the inclusion criteria were included in the study. Most of participants were in a chronic stage and were between 14 and 85 years old. The VR-based gait training ranged from nonimmersive to immersive, was mostly performed on a treadmill, and was usually combined with conventional physiotherapy. The duration of the program varied from 10 to 60 min, and there were about 9 to 30 sessions. VR-based gait rehabilitation has a positive effect on gait ability. The existing literature suggests that VR-based rehabilitation combined with conventional physiotherapy could improve gait ability of people with stroke, especially in the chronic stage. However, the duration of VR-based programs should be customized to suit individuals to avoid stimulation sickness. Further research is needed to investigate the long-term effects of this approach.

Effectiveness of Repetitive Transcranial Magnetic Stimulation Combined with Visual Feedback Training in Improving Neuroplasticity and Lower Limb Function after Chronic Stroke: A Pilot Study

After a stroke, sustained gait impairment can restrict participation in the activities listed in the International Classification of Functioning, Disability, and Health model and cause poor quality of life. The present study investigated the effectiveness of repetitive transcranial magnetic stimulation (rTMS) and visual feedback training (VF) training in improving lower limb motor performance, gait, and corticospinal excitability in patients with chronic stroke. Thirty patients were randomized into three groups that received either rTMS or sham stimulation over the contralesional leg region accompanied by VF training groups in addition to the conventional rehabilitation group. All participants underwent intervention sessions three times per week for four weeks. Outcome measures included the motor-evoked potential (MEP) of the anterior tibialis muscle, Berg Balance Scale (BBS) scores, Timed Up and Go (TUG) test scores, and Fugl–Meyer Assessment of Lower Extremity scores. After the intervention, the rTMS and VF group had significantly improved in MEP latency (p = 0.011), TUG scores (p = 0.008), and BBS scores (p = 0.011). The sham rTMS and VF group had improved MEP latency (p = 0.027). The rTMS and VF training may enhance the cortical excitability and walking ability of individuals with chronic stroke. The potential benefits encourage a larger trial to determine the efficacy in stroke patients.

Limb loading enhances skill transfer between augmented and physical reality tasks during limb loss rehabilitation

BACKGROUND

Virtual and augmented reality (AR) have become popular modalities for training myoelectric prosthesis control with upper-limb amputees. While some systems have shown moderate success, it is unclear how well the complex motor skills learned in an AR simulation transfer to completing the same tasks in physical reality. Limb loading is a possible dimension of motor skill execution that is absent in current AR solutions that may help to increase skill transfer between the virtual and physical domains.

METHODS

We implemented an immersive AR environment where individuals could operate a myoelectric virtual prosthesis to accomplish a variety of object relocation manipulations. Intact limb participants were separated into three groups, the load control (CG_LD; [Formula: see text]), the AR control (CG_AR; [Formula: see text]), and the experimental group (EG; [Formula: see text]). Both the CG_AR and EG completed a 5-session prosthesis training protocol in AR while the CG_LD performed simple muscle training. The EG attempted manipulations in AR while undergoing limb loading. The CG_AR attempted the same manipulations without loading. All participants performed the same manipulations in physical reality while operating a real prosthesis pre- and post-training. The main outcome measure was the change in the number of manipulations completed during the physical reality assessments (i.e. completion rate). Secondary outcomes included movement kinematics and visuomotor behavior.

RESULTS

The EG experienced a greater increase in completion rate post-training than both the CG_AR and CG_LD. This performance increase was accompanied by a shorter motor learning phase, the EG's performance saturating in less sessions of AR training than the CG_AR.

CONCLUSION

The results demonstrated that limb loading plays an important role in transferring complex motor skills learned in virtual spaces to their physical reality analogs. While participants who did not receive limb loading were able to receive some functional benefit from AR training, participants who received the loading experienced a greater positive change in motor performance with their performance saturating in fewer training sessions.

Evolution of postural control assessment: From dynamic posturography to virtual reality

During the early years of spaceflight it was documented that astronauts were impaired and incapacitated upon return to earth. Computerized Dynamic Posturography (CDP) was devised to investigate and quantify this deficit, and eventually progressed into a clinical assessment tool. The current sprouting of virtual reality (VR) technologies has allowed for the development of an alternative approach that could be more informative. Many low-cost VR systems (including desktop gaming programs designed for rehabilitation) are now available. Continued improvements in this technology indicate a high probability that VR will become an integral component of posturography by replacing present mechanical CDP techniques. We researched the relevant literature to evaluate the strengths and weaknesses of CDP using the Equitest (Neurocom International; Clackamas USA), and the added benefits of incorporating VR to help clinicians assess the complex task of balance maintenance. VR is capable of manipulating task and environmental demands in order to assess functional postural behavior. VR is also a useful tool for clinical testing of postural disorders resulting from sensory mismatch. Although posturography is still a useful clinical tool, VR provides an inherent conflict between the visual and vestibular senses and can elevate the effectiveness of CDP for both assessment and intervention. We conclude that, when initially developed, CDP was innovative and ahead of its time. However, with the advent of VR, we have a chance to modernize CDP and enhance its value as a clinical instrument.

Effect of immersive visualization technologies on cognitive load, motivation, usability, and embodiment

Virtual reality (VR) is a promising tool to promote motor (re)learning in healthy users and brain-injured patients. However, in current VR-based motor training, movements of the users performed in a three-dimensional space are usually visualized on computer screens, televisions, or projection systems, which lack depth cues (2D screen), and thus, display information using only monocular depth cues. The reduced depth cues and the visuospatial transformation from the movements performed in a three-dimensional space to their two-dimensional indirect visualization on the 2D screen may add cognitive load, reducing VR usability, especially in users suffering from cognitive impairments. These 2D screens might further reduce the learning outcomes if they limit users' motivation and embodiment, factors previously associated with better motor performance. The goal of this study was to evaluate the potential benefits of more immersive technologies using head-mounted displays (HMDs). As a first step towards potential clinical implementation, we ran an experiment with 20 healthy participants who simultaneously performed a 3D motor reaching and a cognitive counting task using: (1) (immersive) VR (IVR) HMD, (2) augmented reality (AR) HMD, and (3) computer screen (2D screen). In a previous analysis, we reported improved movement quality when movements were visualized with IVR than with a 2D screen. Here, we present results from the analysis of questionnaires to evaluate whether the visualization technology impacted users' cognitive load, motivation, technology usability, and embodiment. Reports on cognitive load did not differ across visualization technologies. However, IVR was more motivating and usable than AR and the 2D screen. Both IVR and AR rea ched higher embodiment level than the 2D screen. Our results support our previous finding that IVR HMDs seem to be more suitable than the common 2D screens employed in VR-based therapy when training 3D movements. For AR, it is still unknown whether the absence of benefit over the 2D screen is due to the visualization technology per se or to technical limitations specific to the device.

Naturalistic visualization of reaching movements using head-mounted displays improves movement quality compared to conventional computer screens and proves high usability

BACKGROUND

The relearning of movements after brain injury can be optimized by providing intensive, meaningful, and motivating training using virtual reality (VR). However, most current solutions use two-dimensional (2D) screens, where patients interact via symbolic representations of their limbs (e.g., a cursor). These 2D screens lack depth cues, potentially deteriorating movement quality and increasing cognitive load. Head-mounted displays (HMDs) have great potential to provide naturalistic movement visualization by incorporating improved depth cues, reduce visuospatial transformations by rendering movements in the space where they are performed, and preserve eye-hand coordination by showing an avatar-with immersive VR (IVR)-or the user's real body-with augmented reality (AR). However, elderly populations might not find these novel technologies usable, hampering potential motor and cognitive benefits.

METHODS

We compared movement quality, cognitive load, motivation, and system usability in twenty elderly participants (>59 years old) while performing a dual motor-cognitive task with different visualization technologies: IVR HMD, AR HMD, and a 2D screen. We evaluated participants' self-reported cognitive load, motivation, and usability using questionnaires. We also conducted a pilot study with five brain-injured patients comparing the visualization technologies while using an assistive device.

RESULTS

Elderly participants performed straighter, shorter duration, and smoother movements when the task was visualized with the HMDs than screen. The IVR HMD led to shorter duration movements than AR. Movement onsets were shorter with IVR than AR, and shorter for both HMDs than the screen, potentially indicating facilitated reaction times due to reduced cognitive load. No differences were found in the questionnaires regarding cognitive load, motivation, or usability between technologies in elderly participants. Both HMDs proved high usability in our small sample of patients.

CONCLUSIONS

HMDs are a promising technology to be incorporated into neurorehabilitation, as their more naturalistic movement visualization improves movement quality compared to conventional screens. HMDs demonstrate high usability, without decreasing participants' motivation, and might potentially lower cognitive load. Our preliminary clinical results suggest that brain-injured patients may especially benefit from more immersive technologies. However, larger patient samples are needed to draw stronger conclusions.*.

Dropout rate in randomised controlled trials of balance and gait rehabilitation in multiple sclerosis: is it expected to be different for virtual reality-based interventions? A systematic review with meta-analysis and meta-regression

To assess and meta-analyse the pooled dropout rate from the randomised control trilas that use virtual reality for balance or gait rehabilitation in people with multiple sclerosis. A systematic review of randomised control trials with meta-analysis and meta-regressions was performed. A search was conducted in PubMed, Scopus, Web of Science, the Physiotherapy Evidence Database, the Cochrane Database, CINHAL, LILACS, ScienceDirect, and ProQuest. It was last updated in July 2022. After the selection of studies, a quality appraisal was carried out using the PEDro Scale and the Revised Cochrane risk-of-bias tool for randomised trials. A descriptive analysis of main characteristics and dropout information was performed. An overall proportion meta-analysis calculated the pooled dropout rate. Odds ratio meta-analysis compared the dropout likelihood between interventions. The meta-regression evaluated the influence of moderators related to dropout. Sixteen studies with 656 participants were included. The overall pooled dropout rate was 6.6% and 5.7% for virtual reality and 9.7% in control groups. The odds ratio (0.89, p = 0.46) indicated no differences in the probability of dropouts between the interventions. The number, duration, frequency, and weeks of sessions, intervention, sex, multiple sclerosis phenotype, Expanded Disability Status Scale score, and PEDro score were not moderators (p > 0.05). Adverse events were not reported and could not be analysed as moderators. Dropouts across the virtual reality and control comparators were similar without significant differences. Nonetheless, there is a slight trend that could favour virtual reality. Standardisation in reporting dropouts and adverse events is recommended for future trials. PROSPERO database, registration number ID CRD42021284989.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10055-022-00733-4.

Immersive virtual reality for upper limb rehabilitation: comparing hand and controller interaction

Virtual reality shows great potential as an alternative to traditional therapies for motor rehabilitation given its ability to immerse the user in engaging scenarios that abstract them from medical facilities and tedious rehabilitation exercises. This paper presents a virtual reality application that includes three serious games and that was developed for motor rehabilitation. It uses a standalone headset and the user's hands without the need for any controller for interaction. Interacting with an immersive virtual reality environment using only natural hand gestures involves an interaction that is similar to that of real life, which would be especially desirable for patients with motor problems. A study involving 28 participants (4 with motor problems) was carried out to compare two types of interaction (hands vs. controllers). All of the participants completed the exercises. No significant differences were found in the number of attempts necessary to complete the games using the two types of interaction. The group that used controllers required less time to complete the exercise. The performance outcomes were independent of the gender and age of the participants. The subjective assessment of the participants with motor problems was not significantly different from the rest of the participants. With regard to the interaction type, the participants mostly preferred the interaction using their hands (78.5%). All four participants with motor problems preferred the hand interaction. These results suggest that the interaction with the user's hands together with standalone headsets could improve motivation, be well accepted by motor rehabilitation patients, and help to complete exercise therapy at home.

A social VR-based collaborative exergame for rehabilitation: codesign, development and user study

Immersive virtual reality (VR)-based exercise video games (exergames) are increasingly being employed as a supportive intervention in rehabilitation programs to promote engagement in physical activity, especially for elderly users. A multifaceted and iterative codesign process is essential to develop sustainable exergaming solutions. The social aspect is considered one of the key motivating factors in exergames; however, research on the social aspect of VR exergames has been limited. Previous studies have relied on competitiveness in exergames, but research has shown that competition can lead to adverse effects on users. With the aim of motivating elderly individuals to participate in physical exercise and improving social connectedness during rehabilitation, this work presents a social VR-based collaborative exergame codesigned with elderly participants and therapists. This exergame stimulates full-body exercise and supports social collaboration among users through a collaborative game task. Furthermore, this article presents a user study based on a mixed-methods approach to gather user feedback on exergame design and the effect of social collaboration versus playing alone in a VR exergame in terms of physical exertion and motivation. This study spanned five weeks (99 exergaming sessions) with 14 elderly participants divided into two groups, one playing collaboratively and the other playing individually. Between-group comparisons were performed at baseline (first week) and in the fourth week, and within-group comparisons were performed in the fifth week, when the participants played the exergame in counterbalanced order. In contrast to the first week, the participants exergaming collaboratively in the fourth week reported significantly higher intrinsic motivation on all subscales (enjoyment: p < 0.02, effort: p < 0.002, usefulness: p < 0.01) and physical exertion (p < 0.001) than those playing alone. Thereafter, exergaming in counterbalanced order during the fifth week resulted in significant differences (medium to large effect size) within groups. The participants found the social VR gameplay enjoyable and agreed that collaboration played a vital role in their motivation. They reported various health benefits, a minimal increase in symptoms of simulator sickness, and excellent usability scores (83.75±13.3). In this work, we also identify various key design principles to support healthcare professionals, researchers and industrial experts in developing ergonomic and sustainable VR-based exergames for senior citizens.

Investigating the effectiveness of immersive VR skill training and its link to physiological arousal

This paper details the motivations, design, and analysis of a study using a fine motor skill training task in both VR and physical conditions. The objective of this between-subjects study was to (a) investigate the effectiveness of immersive virtual reality for training participants in the 'buzz-wire' fine motor skill task compared to physical training and (b) investigate the link between participants' arousal with their improvements in task performance. Physiological arousal levels in the form of  electro-dermal activity (EDA) and ECG (Electrocardiogram) data were collected from 87 participants, randomly distributed across the two conditions. Results indicated that VR training is as good as, or even slightly better than, training in physical training in improving task performance. Moreover, the participants in the VR condition reported an increase in self-efficacy and immersion, while marginally significant differences were observed in the presence and the temporal demand (retrieved from NASA-TLX measurements). Participants in the VR condition showed on average less arousal than those in the physical condition. Though correlation analyses between performance metrics and arousal levels did not depict any statistically significant results, a closer examination of EDA values revealed that participants with lower arousal levels during training, across conditions, demonstrated better improvements in performance than those with higher arousal. These findings demonstrate the effectiveness of VR in training and the potential of using arousal and training performance data for designing adaptive VR training systems. This paper also discusses implications for researchers who consider using biosensors and VR for motor skill experiments.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10055-022-00699-3.

Increased cognitive load in immersive virtual reality during visuomotor adaptation is associated with decreased long-term retention and context transfer

BACKGROUND

Complex motor tasks in immersive virtual reality using a head-mounted display (HMD-VR) have been shown to increase cognitive load and decrease motor performance compared to conventional computer screens (CS). Separately, visuomotor adaptation in HMD-VR has been shown to recruit more explicit, cognitive strategies, resulting in decreased implicit mechanisms thought to contribute to motor memory formation. However, it is unclear whether visuomotor adaptation in HMD-VR increases cognitive load and whether cognitive load is related to explicit mechanisms and long-term motor memory formation.

METHODS

We randomized 36 healthy participants into three equal groups. All groups completed an established visuomotor adaptation task measuring explicit and implicit mechanisms, combined with a dual-task probe measuring cognitive load. Then, all groups returned after 24-h to measure retention of the overall adaptation. One group completed both training and retention tasks in CS (measuring long-term retention in a CS environment), one group completed both training and retention tasks in HMD-VR (measuring long-term retention in an HMD-VR environment), and one group completed the training task in HMD-VR and the retention task in CS (measuring context transfer from an HMD-VR environment). A Generalized Linear Mixed-Effect Model (GLMM) was used to compare cognitive load between CS and HMD-VR during visuomotor adaptation, t-tests were used to compare overall adaptation and explicit and implicit mechanisms between CS and HMD-VR training environments, and ANOVAs were used to compare group differences in long-term retention and context transfer.

RESULTS

Cognitive load was found to be greater in HMD-VR than in CS. This increased cognitive load was related to decreased use of explicit, cognitive mechanisms early in adaptation. Moreover, increased cognitive load was also related to decreased long-term motor memory formation. Finally, training in HMD-VR resulted in decreased long-term retention and context transfer.

CONCLUSIONS

Our findings show that cognitive load increases in HMD-VR and relates to explicit learning and long-term motor memory formation during motor learning. Future studies should examine what factors cause increased cognitive load in HMD-VR motor learning and whether this impacts HMD-VR training and long-term retention in clinical populations.

Directed information flow during laparoscopic surgical skill acquisition dissociated skill level and medical simulation technology

Virtual reality (VR) simulator has emerged as a laparoscopic surgical skill training tool that needs validation using brain-behavior analysis. Therefore, brain network and skilled behavior relationship were evaluated using functional near-infrared spectroscopy (fNIRS) from seven experienced right-handed surgeons and six right-handed medical students during the performance of Fundamentals of Laparoscopic Surgery (FLS) pattern of cutting tasks in a physical and a VR simulator. Multiple regression and path analysis (MRPA) found that the FLS performance score was statistically significantly related to the interregional directed functional connectivity from the right prefrontal cortex to the supplementary motor area with F (2, 114) = 9, p < 0.001, and R² = 0.136. Additionally, a two-way multivariate analysis of variance (MANOVA) found a statistically significant effect of the simulator technology on the interregional directed functional connectivity from the right prefrontal cortex to the left primary motor cortex (F (1, 15) = 6.002, p = 0.027; partial η² = 0.286) that can be related to differential right-lateralized executive control of attention. Then, MRPA found that the coefficient of variation (CoV) of the FLS performance score was statistically significantly associated with the CoV of the interregionally directed functional connectivity from the right primary motor cortex to the left primary motor cortex and the left primary motor cortex to the left prefrontal cortex with F (2, 22) = 3.912, p = 0.035, and R² = 0.262. This highlighted the importance of the efference copy information from the motor cortices to the prefrontal cortex for postulated left-lateralized perceptual decision-making to reduce behavioral variability.

Instantaneous effects of mindfulness meditation on tennis return performance in elite junior athletes completing an implicitly sequenced serve return task

Single-session meditation augmentation of sport-specific skill performance was tested with elite junior tennis athletes. Athletes completed one of two styles of mindfulness meditation (focused-attention or open-monitoring) or a control listening condition prior to performing an implicitly sequenced tennis serve return task involving the goal of hitting a target area placed on the service court. Unbeknownst to athletes, six distinct serves followed a repeating second-order conditional sequence for two task blocks before the sequence was altered in a third transfer block. Task performance was operationalized as serve return outcome and analyzed using beta regression modeling. Models analyzed group by block differences in the proportion of returned serves (i.e., non-aces), returns placed in the service court, and target hits. Contrary to previous laboratory findings, results did not support meditation-related augmentation of performance and/or sequence learning. In fact, compared to control, meditation may have impaired performance improvements and acquisition of serve sequence information. It is possible that the effects of single-session meditation seen in laboratory research may not extend to more complex motor tasks, at least in highly-trained adolescents completing a well-learned skill. Further research is required to elucidate the participant, task, and meditation-related characteristics that might promote single-session meditation performance enhancement.

Synchrony in triadic jumping performance under the constraints of virtual reality

The use of an immersive virtual reality system as a work space for sports and physical education can help maintain physical communication from separate places. In this study, we verified the possibility of constructing a movement synchrony system by reproducing the mathematical ordered pattern of “triadic jumping” in a virtual space. Three jumpers were asked to move together in a space that was cramped and insufficient for them to pass each other. Within this restricted space, the ordered pattern of the jumpers’ synchrony systematically transited to another state depending on the geometrical configuration of the work space. Although the temporal rigidity of the synchrony was partially lost, the ordered pattern of the “triadic jumping” synchrony that emerged in the virtual space was qualitatively equivalent to that emerging in real space. We believe the idea of expanding the work space for physical education to a virtual one could turn into reality if the sensory feedback of the collision successfully improves the spatial-temporal rigidity of the joint action ordered pattern.

Efficacy and Moderators of Virtual Reality for Cognitive Training in People with Dementia and Mild Cognitive Impairment: A Systematic Review and Meta-Analysis

BACKGROUND

Mild cognitive impairment (MCI) and dementia result in cognitive decline which can negatively impact everyday functional abilities and quality of life. Virtual reality (VR) interventions could benefit the cognitive abilities of people with MCI and dementia, but evidence is inconclusive.

OBJECTIVE

To investigate the efficacy of VR training on global and domain-specific cognition, activities of daily living and quality of life. To explore the influence of priori moderators (e.g., immersion type, training type) on the effects of VR training. Adverse effects of VR training were also considered.

METHODS

A systematic literature search was conducted on all major databases for randomized control trial studies. Two separate meta-analyses were performed on studies with people with MCI and dementia.

RESULTS

Sixteen studies with people with MCI and four studies with people with dementia were included in each meta-analysis. Results showed moderate to large effects of VR training on global cognition, attention, memory, and construction and motor performance in people with MCI. Immersion and training type were found to be significant moderators of the effect of VR training on global cognition. For people with dementia, results showed moderate to large improvements after VR training on global cognition, memory, and executive function, but a subgroup analysis was not possible.

CONCLUSION

Our findings suggest that VR training is an effective treatment for both people with MCI and dementia. These results contribute to the establishment of practical guidelines for VR interventions for patients with cognitive decline.

Human Stiffness Perception and Learning in Interacting With Compliant Environments

Humans are capable of adjusting their posture stably when interacting with a compliant surface. Their whole-body motion can be modulated in order to respond to the environment and reach to a stable state. In perceiving an uncertain external force, humans repetitively push it and learn how to produce a stable state. Research in human motor control has led to the hypothesis that the central nervous system integrates an internal model with sensory feedback in order to generate accurate movements. However, how the brain understands external force through exploration movements, and how humans accurately estimate a force from their experience of the force, is yet to be fully understood. To address these questions, we tested human behaviour in different stiffness profiles even though the force at the goal was the same. We generated one linear and two non-linear stiffness profiles, which required the same force at the target but different forces half-way to the target; we then measured the differences in the learning performance at the target and the differences in perception at the half-way point. Human subjects learned the stiffness profile through repetitive movements in reaching the target, and then indicated their estimation of half of the target value (position and force separately). This experimental design enabled us to probe how perception of the force experienced in different profiles affects the participants' estimations. We observed that the early parts of the learning curves were different for the three stiffness profiles. Secondly, the position estimates were accurate independent of the stiffness profile. The estimation in position was most likely influenced by the external environment rather than the profile itself. Interestingly, although visual information about the target had a large influence, we observed significant differences in accuracy of force estimation according to the stiffness profile.

Transition from predictable to variable motor cortex and striatal ensemble patterning during behavioral exploration

Animals can capitalize on invariance in the environment by learning and automating highly consistent actions; however, they must also remain flexible and adapt to environmental changes. It remains unclear how primary motor cortex (M1) can drive precise movements, yet also support behavioral exploration when faced with consistent errors. Using a reach-to-grasp task in rats, along with simultaneous electrophysiological monitoring in M1 and dorsolateral striatum (DLS), we find that behavioral exploration to overcome consistent task errors is closely associated with tandem increases in M1 and DLS neural variability; subsequently, consistent ensemble patterning returns with convergence to a new successful strategy. We also show that compared to reliably patterned intracranial microstimulation in M1, variable stimulation patterns result in significantly greater movement variability. Our results thus indicate that motor and striatal areas can flexibly transition between two modes, reliable neural pattern generation for automatic and precise movements versus variable neural patterning for behavioral exploration.

It is not fully understood how behavioral flexibility is established in the context of automatic performance of a complex motor skill. Here the authors show that corticostriatal activity can flexibly transition between two modes during a reach to-grasp task in rats: reliable neural pattern generation for precise, automatic movements versus variable neural patterning for behavioral exploration.

Virtual reality is a promising therapy tool for walking activities in pediatric neurorehabilitation: Evaluation of usability and user experience (Preprint)

Background

Objective

Methods

Results

Conclusions

Using Artificial Intelligence for Assistance Systems to Bring Motor Learning Principles into Real World Motor Tasks

Humans learn movements naturally, but it takes a lot of time and training to achieve expert performance in motor skills. In this review, we show how modern technologies can support people in learning new motor skills. First, we introduce important concepts in motor control, motor learning and motor skill learning. We also give an overview about the rapid expansion of machine learning algorithms and sensor technologies for human motion analysis. The integration between motor learning principles, machine learning algorithms and recent sensor technologies has the potential to develop AI-guided assistance systems for motor skill training. We give our perspective on this integration of different fields to transition from motor learning research in laboratory settings to real world environments and real world motor tasks and propose a stepwise approach to facilitate this transition.

A Narrative Review of the Current State of Extended Reality Technology and How it can be Utilised in Sport

Extended reality is an umbrella term used to describe three computer-generated technologies including virtual reality, augmented reality and mixed reality. Extended reality is an emerging technology that has been utilised in many high-performance domains including psychology, medicine and the military, with the aim of enhancing perceptual-cognitive skills and motor skills. However, the use of extended reality in sport, particularly at the elite level, has only recently started to receive attention. While the growth of extended reality technology continues to accelerate at a rapid rate, empirical evidence aimed at understanding how these devices can best be applied in high-performance sport has not followed suit. Therefore, the purpose of this review is to provide clarity for high-performance sport organisations, researchers, sport scientists, coaches and athletes about the current state of extended reality technology and how it has been utilised in sport. In doing so, we first define and give examples of the types of extended reality technology including virtual reality, augmented reality and mixed reality that are available at the present time. Second, we detail how skill acquisition principles underpinned by the theoretical framework of ecological dynamics can be used to help inform the design and assessment of extended reality training tools. Third, we describe how extended reality has been utilised in sport, including how extended reality tools have been assessed for their level of representativeness, and the effectiveness of extended reality training interventions for improving perceptual-cognitive skills and motor skills. Finally, we discuss the future utilisation of extended reality in sport, including the key learnings that can be drawn from other domains, future research directions, practical applications and areas for consideration related to the use of extended reality for training skills in sport.

A Robotic System to Deliver Multiple Physically Bimanual Tasks via Varying Force Fields

Individuals with physical limb disabilities are often restricted to perform activities of daily life (ADLs). While efficacy of bilateral training has been demonstrated in improving physical coordination of human limbs, few robots have been developed in simulating people's ADLs integrated with task-specific force field control. This study sought to develop a bilateral robot for better task rendering of general ADLs (gADLs), where gADL-consistent workspace is achieved by setting linear motors in series, and haptic rendering of multiple bimanual tasks (coupled, uncoupled and semi-coupled) is enabled by regulating force fields between robotic handles. Experiments were conducted with human users, and our results present a viable method of a single robotic system in simulating multiple physically bimanual tasks. In future, the proposed robotic system is expected to be serving as a coordination training device, and its clinical efficacy will be also investigated.

Trajectory Control - An Effective Strategy for Controlling Multi-DOF Upper Limb Prosthetic Devices

Despite great innovations in upper-extremity prosthetic hardware in recent decades, controlling a multiple joint upper limb prosthesis such as an elbow/wrist/hand system is still an open clinical challenge, in large part due to an insufficient number of control inputs available to users. While simultaneous control is in its early stages, the common control approach is sequential control, in which joints and grasps are driven one at a time. In this paper, we introduce and evaluate a concept we call trajectory control, that builds upon this approach, in which motions of the wrist, elbow, and shoulder DOFs (and subsets of them) are coupled into predefined sets of coordinated trajectories; to be selected by the user and driven with a single input variable. These trajectories were designed based on an earlier motion study of activities of daily life obtained from human demonstrations. We experimentally evaluate the efficacy of our approach through a human subjects study in which tasks are performed in a virtual environment. The results show that as device complexity increased (i.e. greater number of DOFs corresponding to more proximal amputations), participants were able to complete tasks faster with trajectory control while exhibiting similar levels of body compensation when compared to sequential and simultaneous control. Additionally, participants found trajectory control to be more intuitive and displayed more natural movement.

Towards functional robotic training: motor learning of dynamic tasks is enhanced by haptic rendering but hampered by arm weight support

Background

Current robot-aided training allows for high-intensity training but might hamper the transfer of learned skills to real daily tasks. Many of these tasks, e.g., carrying a cup of coffee, require manipulating objects with complex dynamics. Thus, the absence of somatosensory information regarding the interaction with virtual objects during robot-aided training might be limiting the potential benefits of robotic training on motor (re)learning. We hypothesize that providing somatosensory information through the haptic rendering of virtual environments might enhance motor learning and skill transfer. Furthermore, the inclusion of haptic rendering might increase the task realism, enhancing participants’ agency and motivation. Providing arm weight support during training might also enhance learning by limiting participants’ fatigue.

Methods

We conducted a study with 40 healthy participants to evaluate how haptic rendering and arm weight support affect motor learning and skill transfer of a dynamic task. The task consisted of inverting a virtual pendulum whose dynamics were haptically rendered on an exoskeleton robot designed for upper limb neurorehabilitation. Participants trained with or without haptic rendering and with or without weight support. Participants’ task performance, movement strategy, effort, motivation, and agency were evaluated during baseline, short- and long-term retention. We also evaluated if the skills acquired during training transferred to a similar task with a shorter pendulum.

Results

We found that haptic rendering significantly increases participants’ movement variability during training and the ability to synchronize their movements with the pendulum, which is correlated with better performance. Weight support also enhances participants’ movement variability during training and reduces participants’ physical effort. Importantly, we found that training with haptic rendering enhances motor learning and skill transfer, while training with weight support hampers learning compared to training without weight support. We did not observe any significant differences between training modalities regarding agency and motivation during training and retention tests.

Conclusion

Haptic rendering is a promising tool to boost robot-aided motor learning and skill transfer to tasks with similar dynamics. However, further work is needed to find how to simultaneously provide robotic assistance and haptic rendering without hampering motor learning, especially in brain-injured patients.

Trial registrationhttps://clinicaltrials.gov/show/NCT04759976

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-00993-w.

Telerehabilitation in response to constrained physical distance: an opportunity to rethink neurorehabilitative routines

Ensuring proper dosage of treatment and repetition over time is a major challenge in neurorehabilitation. However, a requirement of physical distancing to date compromises their achievement. While mostly associated to COVID-19, physical distancing is not only required in a pandemic scenario, but also advised for several clinical conditions (e.g. immunocompromised individuals) or forced for specific social contexts (e.g. people living in remote areas worldwide). All these contexts advocate for the implementation of alternative healthcare models. The objective of this perspective is to highlight the benefits of remote administration of rehabilitative treatment, namely telerehabilitation, in counteracting physical distancing barriers in neurorehabilitation. Sustaining boosters of treatment outcome, such as compliance, sustainability, as well as motivation, telerehabilitation may adapt to multiple neurological conditions, with the further advantage of a high potential for individualization to patient's or pathology's specificities. The effectiveness of telerehabilitation can be potentiated by several technologies available to date: virtual reality can recreate realistic environments in which patients may bodily operate, wearable sensors allow to quantitatively monitor the patient's performance, and signal processing may contribute to the prediction of long-term dynamics of patient recovery. Telerehabilitation might spark its advantages far beyond the mere limitation of physical distancing effects, mitigating criticalities of daily neurorehabilitative practice, and thus paving the way to the envision of mixed models of care, where hospital-based procedures are complementarily integrated with telerehabilitative ones.

Feasibility of a virtual reality-based exercise intervention and low-cost motion tracking method for estimation of motor proficiency in youth with autism spectrum disorder

Background

Motor impairment is widely acknowledged as a core feature in children with autism spectrum disorder (ASD), which can affect adaptive behavior and increase severity of symptoms. Low-cost motion capture and virtual reality (VR) game technologies hold a great deal of promise for providing personalized approaches to motor intervention in ASD. The present study explored the feasibility, acceptability and potential efficacy of a custom-designed VR game-based intervention (GaitWayXR™) for improving gross motor skills in youth with ASD.

Methods

Ten children and adolescents (10–17 years) completed six, 20-min VR-based motor training sessions over 2 weeks while whole-body movement was tracked with a low-cost motion capture system. We developed a methodology for using motion tracking data to quantify whole-body movement in terms of efficiency, synchrony and symmetry. We then studied the relationships of the above quantities with standardized measures of motor skill and cognitive flexibility.

Results

Our results supported our presumption that the VR intervention is safe, with no adverse events and very few minor to moderate side-effects, while a large proportion of parents said they would use the VR game at home, the most prohibitive reasons for adopting the system for home therapy were cost and space. Although there was little evidence of any benefits of the GaitWayXR™ intervention in improving gross motor skills, we showed several positive correlations between the standardized measures of gross motor skills in ASD and our measures of efficiency, symmetry and synchrony from low-cost motion capture.

Conclusions

These findings, though preliminary and limited by small sample size, suggest that low-cost motion capture of children with ASD is feasible with movement exercises in a VR-based game environment. Based on these preliminary findings, we recommend conducting larger-scale studies with methods for improving adherence to VR gaming interventions over longer periods.

Observing errors in a combination of error and correct models favors observational motor learning

Background

Imitative learning is highly effective from infancy to old age; however, little is known about the effects of observing errors during imitative learning. This study aimed to examine how observing errors affected imitative learning performance to maximize its effect.

Methods

In the pre-training session, participants were instructed to pinch at a target force (8 N) with auditory feedback regarding generated force while they watched videos of someone pinching a sponge at the target force. In the pre-test, participants pinched at the target force and did not view a model or receive auditory feedback. In Experiment 1, in the main training session, participants imitated models while they watched videos of pinching at either the incorrect force (error-mixed condition) or target force (correct condition). Then, the exact force generated was measured without receiving auditory feedback or viewing a model. In Experiment 2, using the same procedures, newly recruited participants watched videos of pinching at incorrect forces (4 and 24 N) as the error condition and the correct force as the correct condition.

Results

In Experiment 1, the average force was closer to the target force in the error-mixed condition than in the correct condition. In Experiment 2, the average force in the correct condition was closer to the target force than in the error condition.

Conclusion

Our findings indicated that observing error actions combined with correct actions affected imitation motor learning positively as error actions contained information on things to avoid in the target action. It provides further information to enhance imitative learning in mixed conditions compared to that with correct action alone.

A curtailed task for quantitative evaluation of visuomotor adaptation in the head-mounted display virtual reality environment

To accurately perform a goal-directed movement in continuously changing environments, it is unavoidable for individuals to adapt accordingly. The cerebellum has been known to be responsible for such process, specifically adaptation using sensorimotor information. As shown in previous studies, using HMD-VR technology in an experimental setting has similar advantages as in the real-world environment: researchers can manipulate the experimental environment, precisely control the experiments, and quantitatively analyze errors in real time. Moreover, the HMD-VR environment provides high immersiveness and embodiment which even enhance motor learning and increase engagement and motivation of individuals more than real-world environments do. In our HMD-VR-based task, the subjects were trained to adapt to a condition in which the visual information was artificially 20°clockwise rotated from the actual cursor movement. The subjects used a virtual reality tracker to move the cursor from a starting point to a target that appeared randomly at five locations, 20 cm from the starting point with an interval of 15°. Although no significant side effects were expected from experiencing the HMD-VR environment, we considered the appropriate number of trials for patients with cerebellar disease for future use in clinical settings. To examine the feasibility of our task for analysis of visuomotor adaptation pattern as shown in a real-world-based task, we created and compared two paradigms with a difference in the number of trials. As we expected, the results showed that the heading angle error decreased as the participants of both paradigms continued the task and that there was no significant difference between the two paradigms. Next, we applied our short task paradigm to patients diagnosed with cerebellar ataxia and age-matched controls for further examination of applicability to diagnosis and rehabilitation of the patients. As a result, we observed the distinguishable adaptation pattern of the patient group by using our paradigm. Overall, the results suggest that our paradigm is feasible to analyze the visuomotor adaptation pattern of healthy individuals and patients with cerebellar ataxia so may contribute to the clinical field.

Physical rehabilitation interventions in children with acquired brain injury: a scoping review

AIM

To synthesize the evidence about the characteristics (frequency, intensity, time, type) and effects of physical rehabilitation interventions on functional recovery and performance in daily functioning in children and young people with acquired brain injury (ABI), including traumatic brain injuries (TBI) and non-TBI, during the subacute rehabilitation phase.

METHOD

Using scoping review methodology, a systematic literature search was performed using four databases. Articles were screened by title and abstract and data from eligible studies were extracted for synthesis.

RESULTS

Nine of 3009 studies were included. The results demonstrated a variety of intervention characteristics: frequency varied between 1 and 7 days per week; time of intervention varied between 25 minutes and 6 hours a day; intervention types were specified in seven studies; and none of the included studies reported details of intensity of intervention. All studies reported positive results on the International Classification of Functioning, Disability and Health: Children and Youth (ICF-CY) levels of body function and activities after the intervention period, with study designs of included studies being cohort studies without concurrent controls (n=7) or case reports (n=2).

INTERPRETATION

Inconsistency in results hampers generalizability to guide clinical practice. Physical interventions during subacute rehabilitation have potential to improve functional recovery with intervention characteristics as an important factor influencing its effectiveness. Future well-designed studies are indicated to gain knowledge and optimize rehabilitation practice in paediatric ABI and high-quality research including outcomes across all ICF-CY domains is needed.

Motor Memory Consolidation after Augmented Variability Depends on the Space in which Variability is Introduced

Motor memories undergo a period of consolidation before they become resistant to the practice of another task. Although movement variability is important in motor memory consolidation, its role is not fully understood in redundant tasks where variability can exist along two orthogonal subspaces (the 'task space' and the 'null space') that have different effects on task performance. Here, we used haptic perturbations to augment variability in these different spaces and examined their effect on motor memory consolidation. Participants learned a shuffleboard task, where they held a bimanual manipulandum and made a discrete throwing motion to slide a virtual puck towards a target. The task was redundant because the distance travelled by the puck was determined by the sum of the left and right hand speeds at release. After participants practiced the task, we used haptic perturbations to introduce motor variability in the task space or null space and examined consolidation of the original task on the next day. We found that regardless of the amplitude, augmenting variability in the task space resulted in significantly better consolidation relative to augmenting variability in the null space, but was not different from a control group that practiced with no variability. This benefit of increasing task space variability relative to increasing null space variability was likely due to the fact that it did not disrupt the pre-existing coordination strategy. These results suggest that the effects of variability on motor memory consolidation depend on the interplay between the induced variability and the pre-existing coordination strategy.