Sensation of presence and cybersickness in applications of virtual reality for advanced rehabilitation

Around three years ago, in the special issue on augmented and virtual reality in rehabilitation, the topics of simulator sickness was briefly discussed in relation to vestibular rehabilitation. Simulator sickness with virtual reality applications have also been referred to as visually induced motion sickness or cybersickness. Recently, study on cybersickness has been reported in entertainment, training, game, and medical environment in several journals. Virtual stimuli can enlarge sensation of presence, but they sometimes also evoke unpleasant sensation. In order to safely apply augmented and virtual reality for long-term rehabilitation treatment, sensation of presence and cybersickness should be appropriately controlled. This issue presents the results of five studies conducted to evaluate visually-induced effects and speculate influences of virtual rehabilitation. In particular, the influence of visual and vestibular stimuli on cardiovascular responses are reported in terms of academic contribution

The Effects of Primary and Secondary Task Workloads on Cybersickness in Immersive Virtual Active Exploration Experiences

Virtual reality (VR) technology promises to transform humanity. The technology enables users to explore and interact with computer-generated environments that can be simulated to approximate or deviate from reality. This creates an endless number of ways to propitiously apply the technology in our lives. It follows that large technological conglomerates are pushing for the widespread adoption of VR, financing the creation of the Metaverse - a hypothetical representation of the next iteration of the internet. Even with VR technology\u27s continuous growth, its widespread adoption remains long overdue. This can largely be attributed to an affliction called cybersickness, an analog to motion sickness, which often manifests in users as an undesirable side-effect of VR experiences, inhibiting its sustained usage. This makes it highly important to study factors related to the malady. The tasks performed in a simulated environment provide context, purpose, and meaning to the experience. Active exploration experiences afford users control over their motion, primarily allowing them to navigate through an environment. While navigating, users may also have to engage in secondary tasks that can be distracting. These navigation and distraction tasks differ in terms of the source and magnitude of attentional demands involved, potentially influencing how cyber-sickening a simulation can be. Given the sparse literature in this area, this dissertation sets out to investigate how the interplay between these factors impacts the onset and severity of sickness, thereby contributing to the knowledge base on how the attentional demands associated with the tasks performed during navigation affect cybersickness in virtual reality

Psychometric evaluation of the Simulator Sickness Questionnaire as a measure of cybersickness

Some users of virtual reality (VR) technology experience negative symptoms, known as cybersickness, sometimes severe enough to cause discontinuation of VR use. Despite decades of research, there has been relatively little progress understanding the underlying causal mechanisms of cybersickness. Review of the measures used to assess cybersickness symptoms, particularly the subjective psychological components of cybersickness, indicated that extant questionnaires may exhibit psychometric problems that could affect interpretation of results. In the present study, new data were collected (N = 202) to evaluate the psychometric properties of the Simulator Sickness Questionnaire (SSQ), the most commonly reported measure of cybersickness symptoms, in the context of virtual reality. Findings suggest that the SSQ, as commonly used, is not applicable to VR. An alternative approach to measure cybersickness is suggested. Overall, incidence and severity of cybersickness was very low and participants rated the VR experience as highly entertaining

Improving spatial orientation in virtual reality with leaning-based interfaces

Advancement in technology has made Virtual Reality (VR) increasingly portable, affordable and accessible to a broad audience. However, large scale VR locomotion still faces major challenges in the form of spatial disorientation and motion sickness. While spatial updating is automatic and even obligatory in real world walking, using VR controllers to travel can cause disorientation. This dissertation presents two experiments that explore ways of improving spatial updating and spatial orientation in VR locomotion while minimizing cybersickness. In the first study, we compared a hand-held controller with HeadJoystick, a leaning-based interface, in a 3D navigational search task. The results showed that leaning-based interface helped participant spatially update more effectively than when using the controller. In the second study, we designed a "HyperJump" locomotion paradigm which allows to travel faster while limiting its optical flow. Not having any optical flow (as in traditional teleport paradigms) has been shown to help reduce cybersickness, but can also cause disorientation. By interlacing continuous locomotion with teleportation we showed that user can travel faster without compromising spatial updating

The Perception/Action loop: A Study on the Bandwidth of Human Perception and on Natural Human Computer Interaction for Immersive Virtual Reality Applications

Virtual Reality (VR) is an innovating technology which, in the last decade, has had a widespread success, mainly thanks to the release of low cost devices, which have contributed to the diversification of its domains of application. In particular, the current work mainly focuses on the general mechanisms underling perception/action loop in VR, in order to improve the design and implementation of applications for training and simulation in immersive VR, especially in the context of Industry 4.0 and the medical field. On the one hand, we want to understand how humans gather and process all the information presented in a virtual environment, through the evaluation of the visual system bandwidth. On the other hand, since interface has to be a sort of transparent layer allowing trainees to accomplish a task without directing any cognitive effort on the interaction itself, we compare two state of the art solutions for selection and manipulation tasks, a touchful one, the HTC Vive controllers, and a touchless vision-based one, the Leap Motion. To this aim we have developed ad hoc frameworks and methodologies. The software frameworks consist in the creation of VR scenarios, where the experimenter can choose the modality of interaction and the headset to be used and set experimental parameters, guaranteeing experiments repeatability and controlled conditions. The methodology includes the evaluation of performance, user experience and preferences, considering both quantitative and qualitative metrics derived from the collection and the analysis of heterogeneous data, as physiological and inertial sensors measurements, timing and self-assessment questionnaires. In general, VR has been found to be a powerful tool able to simulate specific situations in a realistic and involving way, eliciting user\u2019s sense of presence, without causing severe cybersickness, at least when interaction is limited to the peripersonal and near-action space. Moreover, when designing a VR application, it is possible to manipulate its features in order to trigger or avoid triggering specific emotions and voluntarily create potentially stressful or relaxing situations. Considering the ability of trainees to perceive and process information presented in an immersive virtual environment, results show that, when people are given enough time to build a gist of the scene, they are able to recognize a change with 0.75 accuracy when up to 8 elements are in the scene. For interaction, instead, when selection and manipulation tasks do not require fine movements, controllers and Leap Motion ensure comparable performance; whereas, when tasks are complex, the first solution turns out to be more stable and efficient, also because visual and audio feedback, provided as a substitute of the haptic one, does not substantially contribute to improve performance in the touchless case

The Effect of Prior Virtual Reality Experience on Locomotion and Navigation in Virtual Environments

VirtualReality(VR) is becoming more accessible and widely utilized in crucial disciplines like training, communication, healthcare, and education. One of the important parts of VR applications is walking through virtual environments. So, researchers have broadly studied various kinds of walking in VR as it can reduce sickness, improve the sense of presence, and enhance the general user experience. Due to the recent availability of consumer Head Mounted Displays (HMDs), people are using HMDs in all sorts of different locations. It underscores the need for locomotion methods that allow users to move through large Immersive Virtual Environments (IVEs) when occupying a small physical space or even seated. Although many aspects of locomotion in VR have received extensive research, very little work has considered how locomotive behaviors might change over time as users become more experienced in IVEs. As HMDs were rarely encountered outside of a lab before 2016, most locomotion research before this was likely conducted with VR novices who had no prior experience with the technology. However, as this is no longer the case, itis important to consider whether locomotive behaviors may evolve over time with user experience. This proposal specifically studies locomotive behaviors and effects that may adjust over time. For the first study, we conducted experiments measuring novice and experienced subjects’ gait parameters in VR and real environments. Prior research has established that users’ gait in virtual and real environments differs; however, little research has evaluated how users’ gait differs as users gain more experience with VR. We conducted experiments measuring novice and experienced subjects’ gait parameters in VR and real environments. Results showed that subjects’ performance in VR and Real World was more similar in the last trials than in the first trials; their walking dissimilarity in the start trials diminished by walking more trials. We found the trials a significant variable affecting the walking speed, step length, and trunk angle for both groups of users. While the main effect of expertise was not observed, an interaction effect between expertise and the trial number was shown. The trunk angle increased over time for novices but decreased for experts. These cond study reports the results of an experiment investigating how users’ behavior with two locomotion methods changed over four weeks: teleportation and joystick-based locomotion. Twenty novice VR users (no more than 1 hour prior experience with any form of walking in VR) were recruited. They loaned an Oculus Quest for four weeks on their own time, including an activity we provided them with. Results showed that the time required to complete the navigation task decreased faster for joystick-based locomotion. Spatial memory improved with time, particularly when using teleportation (which starts disadvantaged to joystick-based locomotion). Also, overall cyber sickness decreased slightly overtime; two dimensions of cyber sickness (nausea and disorientation) increased notably over time using joystick-based navigation. The next study presents the findings of a longitudinal research study investigating the effects of locomotion methods within virtual reality on participants’ spatial awareness during VR experiences and subsequent real-world gait parameters. The study encompasses two distinct environments: the real world and VR. In the real world setting, we analyze key gait parameters, including walking speed, distance traveled, and stepcount, both pre and post-VR exposure, to perceive the influence of VR locomotion on post-VR gait behavior. Additionally, we assess participants’ spatial awareness and the occurrence of simulator sickness, considering two locomotion methods: joy stick and teleportation. Our results reveal significant changes in gait parameters associated with increased VR locomotion experience. Furthermore, we observe a remarkable reduction in cyber sickness symptoms over successive VR sessions, particularly evident among participants utilizing joy stick locomotion. This study contributes to the understanding of gait behavior influenced by VR locomotion technology and the duration of VR immersion. Together, these studies inform how locomotion and navigation behavior may change in VR as users become more accustomed to walking in virtual reality settings. Also, comparative studies on locomotion methods help VR developers to implement the better-suited locomotion method. Thus, it provides knowledge to design and develop VR systems to perform better for different applications and groups of users

Explaining Self-Motion Perception using Virtual Reality in Patients with Ocular Disease

Safe mobility requires accurate object and self-motion perception. This involves processing retinal motion generated by optic flow (which change with eye and head movements) and correctly integrating this with vestibular and proprioceptive cues. Poor sensory feedback of self-motion can lead to increased risks of accidents which impacts quality of life. This is further problematic for those with visual deficits, such as central or peripheral vision loss or impaired binocular vision. The expansion of healthcare into using virtual reality (VR) has allowed the assessment of sensory and motor performance in a safe environment. An advantage of VR is its ability to generate vection (perceived illusory self-motion) and presence (sense of being ‘there’). However, a limitation is the potential to develop cybersickness. Initially, the project examined how binocular vision influences vection in a virtual environment. Observers with or without stereopsis (ability to judge depth binocularly) were asked to compare their perceptual experiences based on psychophysical judgements of magnitude estimation. The findings suggest that the absence of stereopsis impairs accurate judgement of self-motion and reduces perceived presence, however, it was protective for cybersickness. The project then examined the impact of central and peripheral vision loss on self-motion perception by comparing those with age-related macular degeneration (AMD) and glaucoma respectively. Effects of these visual deficits on sensory conflicts involving visual-vestibular interactions was then assessed. Sensory conflict was imposed by altering the gain of simulated head linear head position and angular orientation to be either compatible or incompatible with head movement in two separate experiments. Fixation was used to control gaze during changes in angular head orientation. Vection and presence was higher in those with AMD, compared with those with glaucoma, indicating the importance of regional specificity in visual deficits on self-motion perception. Across studies, vection and presence were predominantly visually mediated despite changes in visual-vestibular sensory conflict. The vestibular system, however, appeared to play a larger role in developing cybersickness. The altered perception of self-motion may worsen mobility, particularly with disease progression. We therefore provide a framework and recommendations for a multidisciplinary patient-centric model of care to maximise quality of life

Simulating Virtual Organizations for Research: A Comparative Empirical Evaluation of Text-Based, Video, and Virtual Reality Video Vignettes

Due to recent technological developments, vignette studies that have traditionally been done in text or video formats can now be done in immersive formats using virtual reality—but are such virtual reality video vignettes superior to traditional vignettes? To address this question, we examine participants’ experiences within a fictitious organization by comparing their responses to a relevant and particularly sensitive organizational phenomenon presented either through written text, a video recording, or a virtual reality experience. The results indicate that participants prefer more immersive methods, and that these increase their attention to critical study details. Moreover, this augments the effect sizes of several measured employee reactions—particularly those with high emotional content—suggesting that virtual reality technology offers a promising avenue for developing ecologically valid vignette studies to measure employee affect. To facilitate and expediate the use of virtual reality video vignettes in organizational research, we provide organizational scholars with a step-by-step instructional guide to develop immersive vignette studies

Clinical Decision Support Systems with Game-based Environments, Monitoring Symptoms of Parkinson’s Disease with Exergames

Parkinson’s Disease (PD) is a malady caused by progressive neuronal degeneration, deriving in several physical and cognitive symptoms that worsen with time. Like many other chronic diseases, it requires constant monitoring to perform medication and therapeutic adjustments. This is due to the significant variability in PD symptomatology and progress between patients. At the moment, this monitoring requires substantial participation from caregivers and numerous clinic visits. Personal diaries and questionnaires are used as data sources for medication and therapeutic adjustments. The subjectivity in these data sources leads to suboptimal clinical decisions. Therefore, more objective data sources are required to better monitor the progress of individual PD patients. A potential contribution towards more objective monitoring of PD is clinical decision support systems. These systems employ sensors and classification techniques to provide caregivers with objective information for their decision-making. This leads to more objective assessments of patient improvement or deterioration, resulting in better adjusted medication and therapeutic plans. Hereby, the need to encourage patients to actively and regularly provide data for remote monitoring remains a significant challenge. To address this challenge, the goal of this thesis is to combine clinical decision support systems with game-based environments. More specifically, serious games in the form of exergames, active video games that involve physical exercise, shall be used to deliver objective data for PD monitoring and therapy. Exergames increase engagement while combining physical and cognitive tasks. This combination, known as dual-tasking, has been proven to improve rehabilitation outcomes in PD: recent randomized clinical trials on exergame-based rehabilitation in PD show improvements in clinical outcomes that are equal or superior to those of traditional rehabilitation. In this thesis, we present an exergame-based clinical decision support system model to monitor symptoms of PD. This model provides both objective information on PD symptoms and an engaging environment for the patients. The model is elaborated, prototypically implemented and validated in the context of two of the most prominent symptoms of PD: (1) balance and gait, as well as (2) hand tremor and slowness of movement (bradykinesia). While balance and gait affections increase the risk of falling, hand tremors and bradykinesia affect hand dexterity. We employ Wii Balance Boards and Leap Motion sensors, and digitalize aspects of current clinical standards used to assess PD symptoms. In addition, we present two dual-tasking exergames: PDDanceCity for balance and gait, and PDPuzzleTable for tremor and bradykinesia. We evaluate the capability of our system for assessing the risk of falling and the severity of tremor in comparison with clinical standards. We also explore the statistical significance and effect size of the data we collect from PD patients and healthy controls. We demonstrate that the presented approach can predict an increased risk of falling and estimate tremor severity. Also, the target population shows a good acceptance of PDDanceCity and PDPuzzleTable. In summary, our results indicate a clear feasibility to implement this system for PD. Nevertheless, long-term randomized clinical trials are required to evaluate the potential of PDDanceCity and PDPuzzleTable for physical and cognitive rehabilitation effects