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At least 19 recordsLinked to original sources

PubMed2005

Rats are able to navigate in virtual environments.

Virtual reality (VR) systems are useful tools that enable users to alter environmental settings and the location of landmarks in an accurate and fast way. Primates have been shown to be able to navigate in virtual environments. For rodents, however, all previous attempts to develop VR systems in which rats behave in the same way as in corresponding 3-D environments have failed. The question arises as to whether, in principle, rodents can be trained to navigate in a properly designed virtual environment (VE), or whether this peculiarity is limited to primates and humans. We built a virtual reality set-up that takes the wide-angle visual system of rats into account. We show for the first time that rats learn spatial tasks in this VE quite readily. This set-up opens up new opportunities for investigations of information processing in navigation (e.g. the importance of optic flow or vestibular input).

Animals↗

PubMed1995

Medicine in virtual environments.

Virtual Environments allow a human to interact with a (computer) system in such a way that a high level of presence in a computer-synthesised world is experienced. In principle, all human senses are involved with the interaction. Many applications may benefit from this type of human-machine interfacing, however, few have emerged so far for medicine. In this paper we elaborate on some realistic potential applications of Virtual Environment technology in the field of medicine. These applications can be found in education/training, therapy, surgery, rehabilitation, diagnosis, telemedicine and biomechanics. The value to be added to these applications by VE technology lies in the fact that patient data or patient models may be moderated to the physician in a more intuitive and natural manner. Despite these potentials, the short-term feasibility of these applications can be put into question for various reasons. Firstly, the current generation of display devices have a resolution that may show to be too low to achieve a sufficiently high degree of realism for medical applications. Secondly, there are no commercially-available actuators for tactile and force feedback which the physician desperately need for the simulation of the contact with the (virtual) patient. Thirdly, the enormous computing power required for these applications (still) needs a considerable investment. With these limitations in mind, we believe that we are at the cradle of a whole new generation of VE applications in medicine.

Computer Simulation↗

PubMed1999

The ergonomics of virtual reality: human factors in developing clinical-oriented virtual environments.

Virtual Reality (VR) is usually described as a collection of technological hardware: a computer capable of 3D real-time animation, a head-mounted display, data gloves equipped with one or more position trackers. However, this focus on technology is disappointing for clinicians interested in developing virtual environments to be used in assessment and therapy. To overcome this limitation this chapter describes VR as an advanced communication tool: a communication medium in the case of multi-user VR and a communication interface in single-user VR. Two are the core characteristics of VR as communication tool: the perceptual illusion of nonmediation and the sense of community. The first characteristic of a satisfying virtual environment is the disappearance of mediation, a level of experience where both the VR system and the physical environment disappear from the user's phenomenal awareness. The second characteristic is the sense of community developed by interaction. Through interaction made possible by multi-user VR, individuals find or form groups that share interests. So, information exchange becomes the carrier for expressing self-concept and eliciting emotional support. Within this view, experiencing presence and telepresence does not depend so much on the faithfulness of the reproduction of 'physical' aspects of 'external reality'--which is also a social production, and not a primitive or 'natural' fact--as on the capacity of simulation to produce a context in which social actors may communicate and cooperate. The consequences of this approach for the design and the development of clinical oriented VR systems are presented, together with the methodological and technical implications for the study of advanced human-computer interaction.

Equipment Design↗

PubMed2006

Systematic evaluation of current control devices used by people with intellectual disabilities in non-immersive virtual environments.

Virtual environments have a role to play in facilitating the acquisition of living skills in people with intellectual disabilities, improving their cognitive skills and providing them with entertainment. However, the currently recommended devices to allow navigation in and interaction with the environments are difficult to use. Using a methodology established in an earlier study, the study aims to systematically document the performance of users with the currently recommended devices in order to (i) inform the design of a usable control device or devices and (ii) act as a baseline against which they can be evaluated. 40 people with severe intellectual disabilities aged 21-67 years used four environments with an equal number of sessions with the different devices being evaluated. Results indicate that when forward movement is provided by the software using the mouse for both navigation and interaction allows better performance both initially and after exposure than using the fire button on the joystick. When the user had to initiate forward movement with the navigation device, the joystick allowed better performance than the arrows on the keyboard. Preventing slippage of the joystick base would make its use much easier and it is suggested that separate devices are retained for navigation and interaction.

Adult↗

PubMed1999

Ergonomic aspects of a virtual environment.

A virtual environment is an interactive graphic system mediated through computer technology that allows a certain level of reality or a sense of presence to access virtual information. To create reality in a virtual environment, ergonomics issues are explored in this paper, aiming to develop the design of presentation formats with related information, that is possible to attain and to maintain user-friendly application.

Computer Simulation↗

PubMed1999

Ataxia following exposure to a virtual environment.

BACKGROUND: Virtual environment (VE) technology has many promising applications in a variety of areas that may likely lead to widespread use as technology progresses and cost decreases. Recent research has demonstrated that simulator sickness, a well-established effect of simulator exposure, can occur with VE exposure as well. Because ataxia (postural unsteadiness) is known to occur following simulator exposure, it might also occur following VE exposure. Simulator sickness and after-effects, such as ataxia, pose severe safety risks and raise serious liability questions. METHOD: A PC-based VE system was used to investigate the occurrence of ataxic decrements in postural stability following a 20-min exposure to a commercially available game. There were 20 male and 20 female undergraduate students who served as participants. Postural stability was assessed using a sensitive, reliable measure of stance involving the velocity of head movement sway along the y-axis. Data on the occurrence of simulator sickness were also collected. Based on findings in other simulators, ataxia was hypothesized to occur. RESULTS: Ataxic decrements in postural stability were not found although simulator sickness did occur. CONCLUSIONS: Several possible factors possibly involved in the lack of ataxia were considered: statistical power; aspects of the postural test; participants' VE adaptation, exposure time, and immersion position; and the task performed. Ataxia may not be associated with short exposures to VEs for tasks which are not highly dynamic and individuals who are not experienced with the system.

Adult↗

PubMed1995

Ophthalmic microsurgical robot and associated virtual environment.

An ophthalmic virtual environment has been developed as part of a teleoperated microsurgical robot built to perform surgery on the eye. The virtual environment is unique in that it incorporates a detailed continuum model of the anatomical structures of the eye, its mechanics and optical properties, together with a less detailed geometric-mechanical model of the face. In addition to providing a realistic visual display of the eye being operated on, the virtual environment simulates tissue properties during manipulation and cutting and the forces involved are determined by solving a mechanical finite element model of the tissue. These forces are then fed back to the operator via a force reflecting master and so the surgeon can experience both the visual and mechanical sensations associated with performing surgery. The virtual environment can be used to enhance the images produced by the camera on the microsurgical slave robot during surgery and as a surgical simulator in which it replaces these images with computer graphics generated from the eye model.

Computer Graphics↗

PubMed2005

Affordable virtual environments: building a virtual beach for clinical use.

Virtual Reality has been used for clinical application for about 10 years and has proved to be an effective tool for treating various disorders. In this paper, we want to share our experience in building a 3D, motion tracked, immersive VR system for pain treatment and biofeedback research.

Bathing Beaches↗

PubMed2002

Analysis of physiological response to two virtual environments: driving and flying simulation.

As virtual reality technology continues to attract significant attention in clinical psychology, especially in the treatment of phobias, physiological monitoring is increasingly considered as an objective measurement tool for studying participants. There are few studies, however, of the normal physiological response to virtual environments or reactions to different virtual environments. The goal of this study is to analyze nonphobic participants' physiological reactions to two virtual environments: driving and flying. Eleven nonphobic participants were exposed to each virtual environment for 15 min. Heart rate, skin resistance, and skin temperature were measured during physiological monitoring, and the Presence and Simulator Sickness Questionnaire scores were obtained after each exposure. This study found that skin resistance and heart rate variability can be used to show arousal of participants exposed to the virtual environment experience and that such measures generally returned to normal over time. The data suggest that skin resistance and heart rate can be used as objective measures in monitoring the reaction of non-phobic participants to virtual environments. We also noted that heart rate variability could be useful for assessing the emotional states of participants.

Adult↗

PubMed2005

Using EMG to anticipate head motion for virtual-environment applications.

In virtual environment (VE) applications, where virtual objects are presented in a see-through head-mounted display, virtual images must be continuously stabilized in space in response to user's head motion. Time delays in head-motion compensation cause virtual objects to "swim" around instead of being stable in space which results in misalignment errors when overlaying virtual and real objects. Visual update delays are a critical technical obstacle for implementing head-mounted displays in applications such as battlefield simulation/training, telerobotics, and telemedicine. Head motion is currently measurable by a head-mounted 6-degrees-of-freedom inertial measurement unit. However, even given this information, overall VE-system latencies cannot be reduced under about 25 ms. We present a novel approach to eliminating latencies, which is premised on the fact that myoelectric signals from a muscle precede its exertion of force, thereby limb or head acceleration. We thus suggest utilizing neck-muscles' myoelectric signals to anticipate head motion. We trained a neural network to map such signals onto equivalent time-advanced inertial outputs. The resulting network can achieve time advances of up to 70 ms.

Adult↗

PubMed2005

Attentive navigation for viewpoint control in virtual environments.

Three-dimensional virtual environments and teleoperation activities depend on the ability to position an egocentric viewpoint at meaningful locations. Evidence from foundational research has led to the development of control strategies that generally adopt an all-or-nothing approach to guiding the viewer to useful vistas. This work examines attentive navigation, a technique for partially automating viewpoint control to promote a supportive yet unscripted exploration of a virtual environment. A collection of three experiments was designed to assess the effectiveness of attentive navigation versus commonly used free navigation techniques. Results show that this approach has promising consequences for improving object recognition, developing an understanding of the configuration of objects, and searching for target objects. Actual or potential applications of this research include improved interaction techniques for extracting information from visual representations, virtual environments, and teleoperation experiences.

Adolescent↗

PubMed2006

Validity of a virtual environment for stroke rehabilitation.

BACKGROUND AND PURPOSE: Virtual environments for use in stroke rehabilitation are in development, but there has been little evaluation of their suitability for this purpose. We evaluated a virtual environment developed for the rehabilitation of the task of making a hot drink. METHODS: Fifty stroke patients undergoing rehabilitation in a UK hospital stroke unit were involved. The performance of stroke rehabilitation patients when making a hot drink had the neurological impairments associated with performance of this task, and the errors observed were compared for standardized task performance in the real world and in a virtual environment. Neurological impairments were measured using standardized assessments. Errors in task performance were assessed rating video recordings and classified into error types. RESULTS: Real-world and virtual environment performance scores were not strongly associated (rho=0.30; P<0.05). Performance scores in both settings were associated with age, Barthel ADL score, Mini Mental State Examination score, and tests of visuospatial function. Real-world performance only was associated with arm function and sequencing ability. Virtual environment performance only was associated with language function and praxis. Participants made different errors during task performance in the real world and in the virtual environment. CONCLUSIONS: Although this virtual environment was usable by stroke rehabilitation patients, it posed a different rehabilitation challenge from the task it was intended to simulate, and so it might not be as effective as intended as a rehabilitation tool. Other virtual environments for stroke rehabilitation in development require similar evaluation.

Activities of Daily Living↗

PubMed2001

Accommodation, occlusion, and disparity matching are used to guide reaching: a comparison of actual versus virtual environments.

The authors used a virtual environment to investigate visual control of reaching and monocular and binocular perception of egocentric distance, size, and shape. With binocular vision, the results suggested use of disparity matching. This was tested and confirmed in the virtual environment by eliminating other information about contact of hand and target. Elimination of occlusion of hand by target destabilized monocular but not binocular performance. Because the virtual environment entails accommodation of an image beyond reach, the authors predicted overestimation of egocentric distances in the virtual relative to actual environment. This was confirmed. The authors used -2 diopter glasses to reduce the focal distance in the virtual environment. Overestimates were reduced by half. The authors conclude that calibration of perception is required for accurate feedforward reaching and that disparity matching is optimal visual information for calibration.

Accommodation, Ocular↗

PubMed2001

Development of virtual environment for treating acrophobia.

Virtual Reality (VR) is a new technology that makes humans communicate with computer. It allows the user to see, hear, feel and interact in a three-dimensional virtual world created graphically. Virtual Reality Therapy (VRT), based on this sophisticated technology, has been recently used in the treatment of subjects diagnosed with acrophobia, a disorder that is characterized by marked anxiety upon exposure to heights, avoidance of heights, and a resulting interference in functioning. Conventional virtual reality system for the treatment of acrophobia has a limitation in scope that it is based on over-costly devices or somewhat unrealistic graphic scene. The goal of this study was to develop a inexpensive and more realistic virtual environment for the exposure therapy of acrophobia. We constructed two types virtual environment. One is constituted a bungee-jump tower in the middle of a city. It includes the open lift surrounded by props beside tower that allowed the patient to feel sense of heights. Another is composed of diving boards which have various heights. It provides a view of a lower diving board and people swimming in the pool to serve the patient stimuli upon exposure to heights.

Altitude↗

PubMed2003

Interpersonal distance in immersive virtual environments.

Digital immersive virtual environment technology (IVET) enables behavioral scientists to conduct ecologically realistic experiments with near-perfect experimental control. The authors employed IVET to study the interpersonal distance maintained between participants and virtual humans. In Study 1, participants traversed a three-dimensional virtual room in which a virtual human stood. In Study 2, a virtual human approached participants. In both studies, participant gender, virtual human gender, virtual human gaze behavior, and whether virtual humans were allegedly controlled by humans (i.e., avatars) or computers (i.e., agents) were varied. Results indicated that participants maintained greater distance from virtual humans when approaching their fronts compared to their backs. In addition, participants gave more personal space to virtual agents who engaged them in mutual gaze. Moreover, when virtual humans invaded their personal space, participants moved farthest from virtual human agents. The advantages and disadvantages of IVET for the study of human behavior are discussed.

Adolescent↗

PubMed2002

Interaction in collaborative educational virtual environments.

The collaborative educational virtual environment supposes the active participation of students and teachers, interacting highly and aiming at knowledge exchange and creation of new abilities. The learning becomes a process in which one assists the other to reach the objective, by exchanging experiences, dialogues, discussion of ideas, accomplishments of the group, and individual activities that can be shared with the group, allowing the creation of knowledge based on collective involvement. In this context, this paper describes and discusses the aspects and methods of interaction between students and teachers in collaborative educational virtual environments and presents an application based on the Virtual Teacher Project.

Cooperative Behavior↗

PubMed2005

Reconstruction and exploration of three-dimensional confocal microscopy data in an immersive virtual environment.

An immersive virtual environment for interactive three-dimensional reconstruction and exploration of confocal microscopy data is presented. For some structures automatic alignment of serial sections can lead to geometric distortions. The superior visual feedback of a Virtual Reality system is used to aid in registering and aligning serial sections interactively. An ImmersaDesk Virtual Reality display system is used for display and interaction with the volumetric confocal data. Detailed methods for handling both single-section and multi-section confocal data are described.

Humans↗

PubMed1998

Virtual environments in neuroscience.

Virtual environments (VE's) let users navigate and interact with computer-generated three-dimensional (3-D) environments in real time, allowing for the control of complex stimuli presentation. These VE's have attracted much attention in medicine, especially in remote or augmented surgery, and surgical training, which are critically dependent on hand-eye coordination. Recently, however, some research projects have begun to test the possibility of using VE's for the study and rehabilitation of human cognitive and functional activities. This paper highlights recent and ongoing research related to the applications of VE's in the neuroscience arena. In particular, it focuses on the American and European initiatives in this field, including a description of the European Commission (EC)-funded VREPAR projects. Finally, the paper provides a general introduction to virtual reality (VR), as it relates to its impact on cognitive and functional abilities.

Computer Systems↗