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PubMed1999

Motion sickness and proprioceptive aftereffects following virtual environment exposure.

To study the potential aftereffects of virtual environments (VE), tests of visually guided behavior and felt limb position (pointing with eyes open and closed) along with self-reports of motion sickness-like discomfort were administered before and after 30 min exposure of 34 subjects. When post- discomfort was compared to a pre-baseline, the participants reported more sickness afterward (p < 0.03). The change in felt limb position resulted in subjects pointing higher (p < 0.038) and slightly to the left, although the latter difference was not statistically significant (p = 0.08). When findings from a second study using a different VE system were compared, they essentially replicated the results of the first study with higher sickness afterward (p < 0.001) and post- pointing errors were also up (p < 0.001) and to the left (p < 0.001). While alternative explanations (e.g. learning, fatigue, boredom, habituation, etc.) of these outcomes cannot be ruled out, the consistency of the post- effects on felt limb position changes in the two VE implies that these recalibrations may linger once interaction with the VE has concluded, rendering users potentially physiologically maladapted for the real world when they return. This suggests there may be safety concerns following VE exposures until pre-exposure functioning has been regained. The results of this study emphasize the need for developing and using objective measures of post-VE exposure aftereffects in order to systematically determine under what conditions these effects may occur.

Adult↗

PubMed2003

Effects of head-slaved navigation and the use of teleports on spatial orientation in virtual environments.

The type of navigation interface in a virtual environment (VE)--head slaved or indirect--determines whether or not proprioceptive feedback stimuli are present during movement. In addition, teleports can be used, which do not provide continuous movement but, rather, discontinuously displace the viewpoint over large distances. A two-part experiment was performed. The first part investigated whether head-slaved navigation provides an advantage for spatial learning in a VE. The second part investigated the role of anticipation when using teleports. The results showed that head-slaved navigation has an advantage over indirect navigation for the acquisition of spatial knowledge in a VE. Anticipating the destination of the teleport prevented disorientation after the displacement to a great extent but not completely. The time that was needed for anticipation increased if the teleport involved a rotation of the viewing direction. This research shows the potential added value of using a head-slaved navigation interface--for example, when using VE for training purposes--and provides practical guidelines for the use of teleports in VE applications.

Adolescent↗

PubMed1998

Basic issues in the use of virtual environments for mental health applications.

In order for Virtual Environments (VE) to be efficiently developed in the areas of clinical psychology and neuropsychology, a number of basic theoretical and pragmatic issues need to be considered. The current status of VE's in these fields, while provocative, is limited by the small number of controlled studies that have been reported which apply this technology to clinical populations. This is to be expected considering it's relatively recent development, expense, and the lack of familiarity with the technology by mainstream researchers in these fields. In spite of this, some work has emerged which can begin to provide a basic foundation of knowledge which could be useful for guiding future research efforts. Although much of the work does not involve the use of fully immersive head mounted displays (HMD's), studies reporting PC-based flatscreen approaches are providing valuable information on issues necessary for the reasonable and measured development of VE/mental health applications. In light of this, the following review will focus on basic issues that we see as important for the development of both HMD and non-HMD VE applications for clinical psychology, neuropsychological assessment, and cognitive rehabilitation. These basic issues are discussed in terms of decision-making for choosing to develop and apply a VE for a mental health application. The chapter covers the issues involved with choosing a VE approach over already existing methods, deciding on the "fit" between a VE approach and the clinical population, level of presence, navigation factors, side effects, generalization, and general methodological and data analysis concerns.

Adult↗

PubMed2006

Three-dimensional virtual environments for blind children.

Information technologies are increasingly helping to integrate and socially include people with visual disabilities. Computing technologies have contributed grandly to attain this goal through innovative techniques and applications. Virtual environments, I/O interfaces, and sound based applications altogether with usability and cognitive impact studies are some of the most used research designs for children with visual disabilities. This study presents the design and usability evaluation of three-dimensional (3D) interactive environments for children with visual disabilities. We introduce AudioChile and AudioVida, interactive virtual environments that can be navigated through 3D sound to enhance spatiality and immersion throughout the environments 3D sound is used to orientate, to avoid obstacles, and to identify the position of diverse personages and objects within the environment. Usability evaluation results indicated that sound can be fundamental for attention and motivation purposes during interaction.

Acoustic Stimulation↗

PubMedDate not supplied

An evaluation of the efficacy of training people with learning disabilities in a virtual environment.

PURPOSE: To evaluate the efficacy of using a virtual kitchen for vocational training of people with learning disabilities. METHOD: Twenty four catering students with learning disabilities participated in the study. Half the students were currently being trained in the kitchen on which the virtual kitchen was modelled but the remaining students were unfamiliar with this kitchen. Students were first pre-tested on four food preparation tasks and identification of 12 hazards in their own training kitchens. They were subsequently trained on one food preparation task and three hazards in their own training kitchens, one food preparation task and three hazards in the virtual kitchen, and one food preparation task and three hazards in specially designed workbooks. They were then retested in their own training kitchens on all the food preparation tasks and all the hazards. RESULTS: Virtual training was found to be as beneficial as real training and more beneficial than workbook and no training in the food preparation tasks. However, virtual, real and workbook training were found to be equally beneficial in the hazard identification task. Students who were unfamiliar with the kitchen on which the virtual kitchen was modelled benefited from virtual training to the same extent as students who were familiar with the kitchen. CONCLUSIONS: Vocational students with learning disabilities were able to use the virtual environment and were motivated to learn using this training method. Depending on the task being trained, virtual training had a more beneficial effect on real task performance than workbook training, even when the virtual kitchen was not modelled on the real training kitchen.

Adolescent↗

PubMed2004

Reaction-time measurement and real-time data acquisition for neuroscientific experiments in virtual environments.

This paper describes an approach to neuroscientific reaction-time experiments and resulting methods for data processing under real-time constraints in virtual environments (VE). Immersive VEs produce huge amounts of data, which has to be processed in real-time to meet the interactivity requirement of VE. Furthermore, data is needed often with a timing resolution and even more crucial with an accuracy in the range of milliseconds. Unfortunately recent operating systems do not in general guarantee timing precision in this range. For these purposes we have researched possibilities for reaction-time measurement and real-time data acquisition. Our system enables neuroscientists to perform reaction-time experiments in platform-independent virtual environments.

Neurosciences↗

PubMed2001

Effects of navigation speed on motion sickness caused by an immersive virtual environment.

This study investigated the effects of navigation speed on the level of motion sickness during and after a 30-min head-steered virtual environment. Root-mean-squares for 8 speeds in the fore-and-aft axis were 3, 4, 6, 8, 10, 24, 30, and 59 m/s. Participants were 96 Chinese men. Both the nausea and vection ratings increased significantly with speeds increasing from 3 m/s to 10 m/s. At speeds exceeding 10 m/s, the ratings stabilized. Navigation speeds were found to significantly affect the onset times of vection and nausea but did not affect their rates of increase with duration of exposure. For the various Simulator Sickness Questionnaire scores, navigation speed had a significant influence on only the oculomotor subscore. Actual or potential applications of this research include the prediction of sickness associated with simulation tours in a virtual environment at different navigation speeds.

Adult↗

PubMed1996

The potentials of virtual environments in the education and training of people with learning disabilities.

The expansion of 'care in the community' has highlighted the need for more effective educational and training media for people with learning disabilities, and this paper suggests that virtual environments (VEs) may help to meet this need. Firstly, key terms (virtual environment, cyberspace and artificial reality) are defined. Secondly, aspects of developmental and cognitive psychological theories and principles of computer-assisted learning are presented that suggest that VEs might be an especially valuable educational media for people with learning disabilities. Thirdly, the existing literature in this field is reviewed. Fourthly, ethical issues associated with the use of VE, both generally and specifically by people with learning disabilities are discussed. Fifth, possible future developments of VEs, both in education and through their convergence with technologies of miniaturization, are suggested. It is concluded that VEs are an effective, affordable, accessible and safe training and educational media for people with learning disabilities, although further research will be required to realise their full potentials.

Computer Systems↗

PubMed2003

A 3D virtual environment rod and frame test: the reliability and validity of four traditional scoring methods for older adults.

This study introduced a 3D rod-and-frame test in a virtual environment (VERF) and evaluated its reliability and concurrent validity according to four scoring methods previously used with 2D tests. Thirty nonimpaired older adults (15 men; 15 women) aged 64-86 (M=73.6) manipulated a rod in a semi-immersive 3D virtual environment. Results suggested that the conventional 2D scoring method of absolute deviation from vertical was the most reliable method (alpha=.79; gamma=.89). This approach also had higher correlations with traditional neuropsychological measures of spatial ability than three other methods. Given the availability of a reliable and valid scoring method, the VERF may result in previously unavailable insights through the measurement of visuospatial abilities in 3D.

Aged↗

PubMed2003

[Treatment of acrophobia in a virtual environment].

Specific phobias are one of the most frequent mental health problems and can lead to years of personal suffering. The most effective treatment is exposure therapy. Our aim was to proof the feasibility and efficacy of virtual environments in treating acrophobia patients using a manually guided exposure therapy. Our pilot study was designed as a crossover intervention with a waiting list condition as a control group. After treatment, our results show that exposure in virtual environments is a feasible technique, can provoke anxiety, and leads to a therapeutic effect.

Adult↗

PubMed1997

Virtual environments for the rehabilitation of disorders of attention and movement.

The incidence of perceptual-motor disorders arising from stroke is steadily increasing in the population of Europe and USA. This chapter sought to define the role that virtual environments may have in designing remedial programmes for rehabilitation following stroke in the areas of attentional retraining and the reacquisition of perceptuo-motor skills. Principles for the structure of guided learning were identified and emphasis placed on the need to identify when and how virtual environments technology can introduce added value to the therapy situation.

Attention Deficit Disorder with Hyperactivity↗

PubMed2001

Spatial ability and learning the use of an angled laparoscope in a virtual environment.

Little is known about the cognitive demands that underlie surgical performance. Several studies have suggested that spatial ability plays a substantial role in surgical skill. An example of a skill in which spatial cognition appears to be of importance is the use of the angled laparoscope. This paper describes a virtual environment designed to assess and train the use of the angled laparoscope. The learning rates of novices learning the skill for the first time in the virtual environment were measured. The rates were found to be highly variable and strongly correlated with spatial ability.

Adolescent↗

PubMed2004

Sex differences in mental rotation and spatial rotation in a virtual environment.

The visuospatial ability referred to as mental rotation has been shown to produce one of the largest and most consistent sex differences, in favor of males, in the cognitive literature. The current study utilizes both a paper-and-pencil version of the mental rotations test (MRT) and a virtual environment for investigating rotational ability among 44 adult subjects. Results replicate sex differences traditionally seen on paper-and-pencil measures, while no sex effects were observed in the virtual environment. These findings are discussed in terms of task demands and motor involvement. Sex differences were also seen in the patterns of correlations between rotation tasks and other neuropsychological measures. Current results suggest men may rely more on left hemisphere processing than women when engaged in rotational tasks.

Adult↗

PubMed2004

Geographical slant facilitates navigation and orientation in virtual environments.

Theoretical considerations and earlier experimental findings indicate that traveling over slanted terrain can lead to an enrichment of the perceived spatial cues relevant for navigation. We investigated the proposed facilitation of a uniformly slanted environment on navigation and orientation performance with a virtual environment presented on a large 180 degrees screen, using as material a virtual town with eight places and twenty-four landmarks. In the control condition, this town was placed on a flat surface; in the two experimental conditions, the town was placed on a slope with a uniform angle of 4 degrees. Pedaling on a bicycle simulator, participants first explored the environment, then solved navigation tasks, pointed from various positions to distant landmarks, judged the relative elevation of pairs of distant landmarks from memory, and finally drew a sketch map of the environment. In comparison to the control condition, the number of navigation errors was significantly lower in the slanted conditions, and the deviations in the pointings to distant landmarks were massively reduced. Participants from the slant conditions also showed good knowledge of the relative elevations of pairs of distant locations. However, no differences in map-drawing quality were found. The results lend additional support to the proposition that our spatial knowledge, which is used in navigation and orientation, contains vertical information.

Adolescent↗

PubMed1995

Endoscopic surgery simulation in a virtual environment.

The minimally invasive nature of endoscopic surgery allows operations to be performed on patients through small incisions, often under local anaesthesia. Patient recovery times and cosmetic detriment are thus greatly reduced, while overall quality of care is improved. Presently, surgeons are trained to perform endosurgical procedures in a number of ways: practising with surgical training devices, using animal models and assisting experienced surgeons. In this paper, the focus is on answering the key question: "Can virtual environment technology assist surgeons in training and maintaining endoscopic surgery skills?" Initial developments towards surgical simulators have clearly demonstrated the great potential of virtual environment technology for surgical training purposes. Breakthroughs towards surgery are expected within the next 5 to 10 years.

Clinical Competence↗

PubMed2002

Virtual food in virtual environments for the treatment of eating disorders.

Eating disorders (Eds) are one of the problems with higher social repercussion in the last years. Sometimes, these clinical syndromes, which are characterized by an altered eating behavior, can have dramatic consequences. In eating disorders, one of the more critical situations, in addition to other of equal or more importance, is the patient's confrontation with food: the visual confrontation, the eating process and the repercussion on his weight. Virtual Reality (VR) technology has been used in psychology, as a therapeutic help tool for the treatment of different psychological problems, for several years now. Their helpfulness is increasingly being recognized. Some developed virtual environments (VE) and their corresponding published studies endorse the efficiency of this tool. Nevertheless, in order to increase the possibilities of success, it is very important to obtain a complete patient immersion in the VE: visual, auditory and interactive. Sometimes there are processes or actions of reality, which are difficult to simulate virtually, and simulating them coarsely would result in the patient lack of immersion in the VE, thus seriously decreasing the possibilities of success. The eating process is an example, since it consists of several steps, some of which (biting, chewing, etc.) don't have an evident virtual solution. This article shows how food and eating process have been simulated virtually in the development of a virtual environment for the treatment of eating disorders.

Adaptation, Psychological↗

PubMed2003

Applications of virtual environments in medicine.

OBJECTIVES: This paper intends to investigate the role of virtual reality (VR) in medicine. In particular it outlines the current state of research and technology that is relevant to the development of effective virtual environments in medicine. METHODS: After describing the two different visions of VR we can find in medicine--the presentation of virtual objects to all of the human senses in a way identical to their natural counterpart, and a new human-computer interaction paradigm in which users are active participants within a computer-generated three-dimensional virtual world--the paper presents some of the most interesting applications actually developed in the area. Finally, it discusses the clinical principles, technological devices and safety issues associated with the use of VR in medicine. RESULTS: With more than 1,000 VR papers already indexed in Medline, VR is a reality health care. Even if the number of controlled studies is still limited, its merging with emerging technologies like Ambient Intelligence and wireless communication will further improve its diffusion. CONCLUSIONS: The possible impact of VR on health care could be even higher than the one offered by the new communication technologies like Internet. In fact, VR is at the same time technology, a communication interface and an experience: a communication interface based on interactive 3D visualization, able to collect and integrate in single real-like experience different inputs and data sets. However, significant efforts are still required to move VR into commercial success and therefore routine clinical use.

Computers↗

PubMed1996

Volume rendering of visible human data for an anatomical virtual environment.

In this work, we utilize the axial anatomical human male sections from the National Library of Medicine's Visible Human Project to generate three-dimensional (3-D) volume representations of the human male subject. The two-dimensional (2-D) projection images were produced by combining ray tracing techniques with automated image segmentation routines. The resultant images provide accurate and realistic volumetric representations of the Visible Human data set which is ultimately needed in medical virtual environment simulation. Ray tracing techniques provide methods by which 2-D volume views of a 3-D voxel array can be produced. The cross-sectional images can be scanned at different angles to produce rotated views of the voxel array. By combining volume views at incremental angles over 360 degrees a full volumetric representation of the voxel array, in this case the human male data set, can be computer generated and displayed without the speed and memory limitations of trying to display the entire data array. Additional texture and feature information can be obtained from the data by applying optical property equations to the ray scans. The imaging effects that can be added to volume renderings using these equations include shading, shadowing, and transparency. The automated segmentation routines provide a means to distinguish between various anatomical structures of the body. These routines can be used to differentiate between skin, fat, muscle, cartilage, blood vessels, and bone. By combining automated segmentation routines with the ray-tracing techniques, 2-D volume views of various anatomical structures and features can be isolated from the full data set. Examples of these segmentation abilities are demonstrated for the human male data set which include volume views of the skeletal systems, the musculoskeletal system, and part of the vascular system. The methods described above allow us to generate lifelike images, NURBS surface models, and realistic texture maps of specific anatomical structures. We have the capability to generate images that are both accurate and lifelike, much like photographic anatomical atlases. We can also generate images, models, and textures that have the clarity of medical artwork/illustrations, by highlighting the coloring of the ray traced structures with conventional colors instead of the natural color of the specimen. We are currently in the process of generating a comprehensive reference atlas of volume rendered images of the human body, soon to be published by Mosby-Year Book. The segmentation techniques needed to create this atlas also offer the accuracy and realism needed to create surface models and texture maps for a virtual environment for surgery simulation.

Anatomy, Cross-Sectional↗