Virtual reality in the rehabilitation of the upper limb after stroke: the user's perspective.

Our group has developed a relatively low-cost virtual reality (VR) system for rehabilitation of the upper limb following stroke. Our system is immersive in that the participant views a representation of their arm and hand, reaching and retrieving objects in the virtual environment (VE), through a head-mounted display (HMD). This is thought to increase the participant's sense of presence in the VE and may lead to improved rehabilitation outcomes. However, use of immersion, particularly with our low-cost system, may increase the incidence of side effects reported. Therefore, the aim of this project was to assess the interaction of healthy users and those following stroke, in terms of their experience of presence in the VE and the rate of self-reported side effects. Differences in rates of perceived exertion, levels of enjoyment, and sense of control between both groups were also explored.     

Factors that influence presence in educational virtual environments.

The present article is a part of a project for the measurement of presence in educational virtual environments (VEs), since presence is correlated with higher levels of cognitive performance and emotional development, factors that contribute to knowledge construction. The aim of our study was to investigate the sense of presence of 12-year-old pupils within an educational VE representing an ancient Greek house through a sense of embodiment and the ability to handle task performance, while using various peripheral devices. This is the first report on presence measurement with children, based on the indication that children and adults may apply very unrelated criteria. Our results showed statistically significant differences on the level of tiredness and ease of use in using six different input devices. The combination of the keyboard and mouse and the keyboard on its own were the least tedious and easiest input devices, giving a sense of presence as stated by the pupils. Environmental richness and the high level of interactivity within the VE resulted in a high degree of presence for almost all the pupils. The majority of them felt a sense of presence whilst driving the avatar, indicating that presence is significantly correlated with pupils' degree of association with their virtual bodies. All the pupils felt a sense of presence when wearing the head-mounted display. Our findings are in line with those of other researchers and show evidence of personal, social and environmental presence.     

Use of Virtual Environments for the Acquisition of Spatial Knowledge: Comparison Among Different Visual Displays

This experiment investigated the effects of three visual display systems differing in immersiveness: A wide field of view (FOV) 3-D helmet-mounted display (HMD); a 3-D HMD with a narrow FOV; and a stationary, rear-projection, wide screen display (WSD). Soldiers explored a virtual environment (VE) representing an actual, unfamiliar heliport. Measures of spatial knowledge of the heliport and presence were recorded. Pretest-posttest differences showed that exploration of the VE transferred to the actual heliport. Visual display had no effect on spatial knowledge of the heliport or on presence. Measures of susceptibility to presence correlated with reported presence only in the WSD condition. Results question popular notions about VEs, which assume that visual-spatial learning is more effective the more immersive the visual display.     

Spatial knowledge acquisition from maps and from navigation in real and virtual environments

In this study, the nature of the spatial representations of an environment acquired from maps, navigation, and virtual environments (VEs) was assessed. Participants first learned the layout of a simple desktop VE and then were tested in that environment. Then, participants learned two floors of a complex building in one of three learning conditions: from a map, from direct experience, or by traversing through a virtual rendition of the building. VE learners showed the poorest learning of the complex environment overall, and the results suggest that VE learners are particularly susceptible to disorientation after rotation. However, all the conditions showed similar levels of performance in learning the layout of landmarks on a single floor. Consistent with previous research, an alignment effect was present for map learners, suggesting that they had formed an orientation-specific representation of the environment. VE learners also showed a preferred orientation, as defined by their initial orientation when learning the environment. Learning the initial simple VE was highly predictive of learning a real environment, suggesting that similar cognitive mechanisms are involved in the two learning situations.     

Dynamic action in virtual environments: constraints on the accessibility of action knowledge in children and adults

In a series of three experiments, we probed the accessibility of action knowledge in different versions of a virtual environment (VE) with 7-year-old children and adults. Using a PHANToM haptic interface, participants performed a virtual throwing task in which they tried to propel a ball from a table to hit a target on the ground. In Experiments 1 and 2, the virtual scene was presented on a computer monitor, and, in Experiment 3, it was projected by using a video projector so that the vertical and horizontal dimensions and the spatial location of the VE corresponded to the real-world dimensions. Results indicate that action knowledge is accessible even in a nonimmersive VE, but also suggest that the need to recalibrate perceptual-motor mappings constrains the accessibility of this kind of intuitive knowledge.     

Distance estimation in a dynamic simulated environment: a visual field dependence problem?

Egocentric distance estimation implies that the subject perceives his own location in the environment. In a simulated environment, subjects have to transpose perceptively their own observation point in order to assume their virtual body position. As only visual information specifies this position, their ability to perceive the camera viewpoint should be linked to the field dependence independence factor (FDI). Field-independent subjects underestimated the mid-distance between their own virtual body position and a far-located target; their bisection was located between the projective (2-D) and the simulated (3-D) mid-distance which indicates their difficulty in considering the in-depth simulated spatial references. High correlations between the vertical estimation in the rod-and-frame test and the egocentric-distance-estimation task (with shifted camera) suggest a similar perceptive process in both tasks. This result is confirmed by the better performances of the field-dependent subjects in this condition. In conclusion, we discuss the relationship between FDI and the sense of presence in virtual environments.     

Dynamic action in virtual environments: Constraints on the accessibility of action knowledge in children and adults

In a series of three experiments, we probed the accessibility of action knowledge in different versions of a virtual environment (VE) with 7-year-old children and adults. Using a PHANToM^TM haptic interface, participants performed a virtual throwing task in which they tried to propel a ball from a table to hit a target on the ground. In Experiments 1 and 2, the virtual scene was presented on a computer monitor, and, in Experiment 3, it was projected by using a video projector so that the vertical and horizontal dimensions and the spatial location of the VE corresponded to the real-world dimensions. Results indicate that action knowledge is accessible even in a nonimmersive VE, but also suggest that the need to recalibrate perceptual-motor mappings constrains the accessibility of this kind of intuitive knowledge.     

Virtual/real transfer of spatial knowledge: benefit from visual fidelity provided in a virtual environment and impact of active navigation

The purpose of this study was to evaluate the effect the visual fidelity of a virtual environment (VE) (undetailed vs. detailed) has on the transfer of spatial knowledge based on the navigation mode (passive vs. active) for three different spatial recall tasks (wayfinding, sketch mapping, and picture sorting). Sixty-four subjects (32 men and 32 women) participated in the experiment. Spatial learning was evaluated by these three tasks in the context of the Bordeaux district. In the wayfinding task, the results indicated that the detailed VE helped subjects to transfer their spatial knowledge from the VE to the real world, irrespective of the navigation mode. In the sketch-mapping task, the detailed VE increased performances compared to the undetailed VE condition, and allowed subjects to benefit from the active navigation. In the sorting task, performances were better in the detailed VE; however, in the undetailed version of the VE, active learning either did not help the subjects or it even deteriorated their performances. These results are discussed in terms of appropriate perceptive-motor and/or spatial representations for each spatial recall task.     

Individual differences in spatial learning from computer-simulated environments

A multivariate study examined relationships between the following factors: paper-and-pencil assessments of verbal and spatial ability, ability to form an accurate spatial representation of a large real-world environment, gender, computer attitudes and experience, proficiency with the navigational interface of a virtual environment (VE), and the ability to acquire and transfer spatial knowledge from a VE. Psychometrically assessed spatial ability and proficiency with the navigational interface were found to make substantial contributions to individual differences in the ability to acquire spatial information from a VE. Gender influenced many VE-related tasks, primarily through its relationship with interface proficiency and spatial ability. Measures of spatial knowledge of a VE maze were highly predictive of subsequent performance in a similar real-world maze, suggesting that VEs can be useful for training people about real-world spaces.     

Presence and emotions in playing a group game in a virtual environment: the influence of body participation

This study assesses the influence of body participation on the sense of presence and emotions, and the relationship between the two dependent variables in playing a group game in a virtual environment. A total of 56 volunteers were asked to play a virtual game in a 360-degree stereoscopic immersive interactive visualization environment using either body movement or a joystick. Presence was measured with the post hoc SUS Presence Questionnaire. The pictorial tool of Self-Assessment Manikin was employed for measuring emotions of arousal and valence. Both arousal and valence positively correlated with presence. However, body participation did not significantly affect reported presence or the above-mentioned emotions.     

Familiarity and environmental representations of a city: a self-report study

"Sense of direction" is usually assessed by self-report. Several internal factors contribute to proficiency in navigation: spatial cognitive style, respondent's sex, and familiarity with the environment; however, questionnaires assessing sense of direction do not include all these factors. In a recent study, Nori and Piccardi reported that environmental familiarity was crucial for topographical orientation. Regardless of a person's spatial cognitive style (i.e., landmark, route, or survey), the greater their familiarity with the environment, the better their performance. In this study, a questionnaire was used, the Familiarity and Spatial Cognitive Style Scale, to measure 208 women's sense of direction and knowledge of their city of residence. Analysis showed that Spatial Cognitive Style predicted sense of direction but not town knowledge. By contrast, familiarity played a crucial role in both areas, confirming the importance of having a tool to assess this factor.     

An experimental study on fear of public speaking using a virtual environment.

This paper examines a necessary condition for successful exploitation of a virtual environment (VE) in therapeutic intervention for fear of public speaking. The condition is that clients experience a degree of anxiety in the VE that is similar to what they would have been expected to experience in a similar real world setting. We refer to this as a "presence" response. The experimental study involved 20 people who were confident public speakers and 16 who were phobic, assessed on a standard psychological scale. Half of each group spoke within a VE depicting an empty seminar room, and the other half within the same room but populated by a neutrally behaving virtual audience of five people. Three responses were measured--a questionnaire-based measure of anxiety, a measure of self-focused attention on somatic responses, and actual heart rate. On all responses, the people with phobia showed a significant increase in signs of anxiety when speaking to the virtual audience compared to the empty room, whereas the confident people did not. The result was strong in spite of the relatively low representational and behavioral fidelity of the virtual characters.     

Overground gait training using virtual reality aimed at gait symmetry

This study investigated if training in a virtual reality (VR) environment that provides visual and audio biofeedback on foot placement can induce changes to spatial and temporal parameters of gait during overground walking. Eighteen healthy young adults walked for 23 min back and forth on an instrumented walkway in three different conditions: (i) real environment (RE), (ii) virtual environment (VE) with no biofeedback, and (iii) VE with biofeedback. Visual and audio biofeedback while stepping on virtual footprint targets appearing along a straight path encouraged participants to walk with an asymmetrical step length (SL). A repeated-measures, one-way ANOVA, followed by a pairwise comparison post-hoc analysis with Bonferroni's correction, was performed to compare the step length difference (SLD), stance phase percentage difference (SPPD), and double-support percentage difference (DSPD) between early and late phases of all walking conditions. The results demonstrate the efficacy of the VE biofeedback system for training asymmetrical gait patterns. Participants temporarily adapted an asymmetrical gait pattern immediately post-training in the VE. Induced asymmetries persisted significantly while later walking in the RE. Asymmetry was significant in the spatial parameters of gait (SLD) but not in the temporal parameters (SPPD and DSPD). This paper demonstrates a method to induce unilateral changes in spatial parameters of gait using a novel VR tool. This study provides a proof-of-concept validation that VR biofeedback training can be conducted directly overground and could potentially provide a new method for treatment of hemiplegic gait or asymmetrical walking.     

Does Narrative Feedback Enhance Children's Motor Learning in a Virtual Environment?

Augmented feedback has motivational and informational functions in motor learning, and is a key feature of practice in a virtual environment (VE). This study evaluated the impact of narrative (story-based) feedback as compared to standard feedback during practice of a novel task in a VE on typically developing children's motor learning, motivation and engagement. Thirty-eight children practiced navigating through a virtual path, receiving narrative or non-narrative feedback following each trial. All participants improved their performance on retention but not transfer, with no significant differences between groups. Self-reported engagement was associated with acquisition, retention and transfer for both groups. A narrative approach to feedback delivery did not offer an additive benefit; additional affective advantages of augmented feedback for motor learning in VEs should be explored.     

Death with a Story

This study investigates how game playing experience changes when a story is added to a first‐person shooter game. Dependent variables include identification, presence, emotional experiences and motivations. When story was present, game players felt greater identification, sense of presence, and physiological arousal. The presence of story did not affect self‐reported arousal or dominance. This study clearly demonstrates that story is something that video game players enjoy; it helps involve them in the game play, makes them feel more immersed in the virtual environment, and keeps them aroused. The greater character identification may be especially worrisome, as past research has shown that justified media violence disinhibits actual aggression on the part of the audience.     

不连续虚拟现实空间中的再定向

虚拟空间的特点之一是具有不连续性, 即在无连接型建筑单元的情况下各个单体间可直接通达的特性。本研究对人在不连续的虚拟空间中的再定向能力进行了探究, 将人类空间再定向能力的研究从现实空间延伸到了虚拟空间, 并研究了人在不同虚拟现实设备中的行为表现差异。结果表明, 人在不连续的虚拟空间中能完成再定向任务, 而虚拟空间中建筑单元的几何信息对人在不连续虚拟空间中的再定向表现无显著影响, 但被试在桌面式虚拟现实中的成绩显著高于在头盔式虚拟现实中的成绩。这些结果表明了人对不连续的虚拟空间的适应性。     

虚拟社区公民行为在虚拟社区感与知识共享意图间的中介作用:自我效能感的调节机制

采用问卷法对445名虚拟社区成员及与其比较亲密的其他社区成员进行调查,探讨了虚拟社区感的三个维度(成员感、影响力、沉浸感)对成员知识共享意图的影响及其内在作用机制。结果表明:(1)成员感对成员知识共享意图具有显著的正向预测作用,而影响力和沉浸感的预测作用不显著;(2)虚拟社区公民行为是成员感对成员知识共享意图作用的中介变量;(3)自我效能感在成员感—虚拟社区公民行为—知识共享意图关系中不具有显著的调节效应。     

Virtual-reality distraction and cold-pressor pain tolerance: does avatar point of view matter?

This study tested the effects of distraction using virtual-reality (VR) technology on acute pain tolerance in young adults. Forty-one undergraduate students, aged 18-23 years, used a VR head-mounted display helmet, steering wheel, and foot pedal to play an auto racing video game while undergoing exposure to very cold water (cold pressor set at 1 °C). Two different game views were tested that were hypothesized to affect the degree to which participants felt "present" in the virtual environment: a first-person view, in which the participant saw the virtual environment through the eyes of the game character being manipulated; and a third-person view, in which the participant viewed the game character from a distance. The length of time participants tolerated the cold-water exposure (pain tolerance) under each distraction condition was compared to a baseline (no distraction) trial. Subjects also rated the degree to which they felt "present" in the virtual environment after each distraction trial. Results demonstrated that participants had significantly higher pain tolerance during both VR-distraction conditions relative to baseline (no distraction) trials. Although participants reported a greater sense of presence during the first-person condition than the third-person condition, pain-tolerance scores associated with the two distraction conditions did not differ. The types of VR applications in which presence may be more or less important are discussed.     

Transfer of route learning from virtual to real environments

The authors investigated the extent to which route learning in a virtual environment (VE) transfers to the real world. In Experiment 1, active VE exploration, on its own or with a map, produced better transfer of training than either no VE training at all or passive VE training; however, transfer was achieved after shorter training times with the map. Experiment 2 demonstrated that VE + map training was not superior to training with a map alone, and Experiment 3 demonstrated that the poorer performances observed after passive VE training were not simply due to a lack of attention but to the lack of active navigational decisions. The authors concluded that the present VE technology does not provide better route learning than studying a map.