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PubMed1996

The virtual gamma camera room.

The installation of a gamma camera is time-consuming and costly and, once installed, the camera position is unlikely to be altered during its working life. Poor choice of camera position therefore has long-term consequences. Additional equipment such as collimators and carts, the operator's workstation and wall-mounted display monitors must also be situated to maximize access and ease of use. The layout of a gamma camera room can be optimized prior to installation by creating a virtual environment. Super-Scape VRT software running on an upgraded 486 PC microprocessor was used to create a 'virtual camera room'. The simulation included an operator's viewpoint and a controlled tour of the room. Equipment could be repositioned as required, allowing potential problems to be identified at the design stage. Access for bed-ridden patients, operator ergonomics, operator and patient visibility were addressed. The display can also be used for patient education. Creation of a virtual environment is a valuable tool which allows different camera systems to be compared interactively in terms of dimensions, extent of movement and use of a defined space. Such a system also has applications in radiopharmacy design and simulation.

Ergonomics↗

PubMed1997

Virtual reality, disability and rehabilitation.

Virtual reality, or virtual environment computer technology, generates simulated objects and events with which people can interact. Existing and potential applications for this technology in the field of disability and rehabilitation are discussed. The main benefits identified for disabled people are that they can engage in a range of activities in a simulator relatively free from the limitations imposed by their disability, and they can do so in safety. Evidence that the knowledge and skills acquired by disabled individuals in simulated environments can transfer to the real world is presented. In particular, spatial information and life skills learned in a virtual environment have been shown to transfer to the real world. Applications for visually impaired people are discussed, and the potential for medical interventions and the assessment and treatment of neurological damage are considered. Finally some current limitations of the technology, and ethical concerns in relation to disability, are discussed.

Activities of Daily Living↗

PubMed2004

Virtual reality exposure in the treatment of social phobia.

Social phobia is one of the most frequent psychiatric disorders and is accessible to two forms of scientifically validated treatments: anti-depressant drugs and cognitive-behavioral therapies. Graded exposure to feared social situations (either in vivo or by imagining the situations) is fundamental to obtain an improvement of the anxious symptoms. Virtual reality (VR) may be an alternative to these standard exposure techniques and seems to bring significant advantages by allowing exposures to numerous and varied situations. Moreover studies have shown that human subjects are appropriately sensitive to virtual environments. This chapter reports the definition of a VR-based clinical protocol and a study to treat social phobia using virtual reality techniques. The virtual environments used in the treatment reproduce four situations that social phobics feel the most threatening: performance, intimacy, scrutiny and assertiveness. With the help of the therapist, the patient learns adapted cognitions and behaviors when coping with social situations, with the aim of reducing her or his anxiety in the corresponding real life situations. Some studies have been carried out using virtual reality in the treatment of fear of public speaking, which is only a small part of the symptomatology of most of social phobic patients. The novelty of our work is to address a larger group of situations that the phobic patients experience with high anxiety. In our protocol, the efficacy of the virtual reality treatment is compared to well established and well validated group cognitive-behavioral treatment.

Adult↗

PubMed2004

Development of a virtual reality environment for somatosensory and perceptual stimulation in the balance assessment of children.

In this study, we developed a balance assessment system in which the visual stimulus was generated by a virtual reality (VR) technique and somatosensation was obtained from a movable platform. By standing on the movable platform, the center of pressure (COP) was measured to express the subject's postural control in response to varied visual stimuli. From the COP data, a singular value decomposition technique was used to derive the sway area and direction, represented in a polar form. Our system demonstrated the feasibility of using a VR environment in postural control trials and provided more realistic somatosensory and visual inputs.

Adolescent↗

PubMedDate not supplied

User interface paradigms for patient-specific surgical planning: lessons learned over a decade of research.

This paper covers work in virtual reality-based, patient-specific surgical planning over the past decade. It aims to comprehensively examine the user interface paradigms and system designs during that period of time and to objectively analyze their effectiveness for the task. The goal is to provide useful feedback on these interface and implementation paradigms to aid other researchers in this field. First, specialized systems for specific clinical use were produced with a limited set of visualization tools. Later, through collaboration with NASA, an immersive virtual environment was created to produce high-fidelity images for surgical simulation, but it underestimated the importance of collaboration. The next system, a networked, distributed virtual environment, provided immersion and collaboration, but the immersive paradigm was found to be of a disadvantage and the uniqueness of the framework unwieldy. A virtual model, workbench-style display was then created using a commercial package, but limitations of each were soon apparent. Finally, a specialized display, with an integrated visualization and simulation system is described and evaluated. Lessons learned include: surgical planning is an abstract process unlike surgical simulation; collaboration is important, as is stereo visualization; and that high-resolution preoperative images from standard viewpoints are desirable, but interaction is truly the key to planning.

Patient-Centered Care↗

PubMed2004

Cognitive enhancers as adjuncts to psychotherapy: use of D-cycloserine in phobic individuals to facilitate extinction of fear.

BACKGROUND: Traditional pharmacological approaches to treating psychiatric disorders focus on correcting presumed biochemical abnormalities. However, some disorders, particularly the anxiety-related disorders exemplified by specific phobia, have an emotional learning component to them that can be facilitated with psychotherapy. OBJECTIVE: To determine whether D-cycloserine (DCS), a partial agonist at the N-methyl-d-aspartate receptor that has previously been shown to improve extinction of fear in rodents, will also improve extinction of fear in human phobic patients undergoing behavioral exposure therapy. DESIGN: Randomized, double-blind, placebo-controlled trial examining DCS vs placebo treatment in combination with a precisely controlled exposure paradigm. SETTING: Participants were recruited from the general community to a research clinic. PARTICIPANTS: Twenty-eight subjects with acrophobia diagnosed by the Structured Clinical Interview for DSM-IV were enrolled. INTERVENTIONS: After we obtained pretreatment measures of fear, subjects were treated with 2 sessions of behavioral exposure therapy using virtual reality exposure to heights within a virtual glass elevator. Single doses of placebo or DCS were taken prior to each of the 2 sessions of virtual reality exposure therapy. Subjects, therapists, and assessors were blind to the treatment condition. Subjects returned at 1 week and 3 months posttreatment for measures to determine the presence and severity of acrophobia symptoms. MAIN OUTCOME MEASURES: Included were measures of acrophobia within the virtual environment, measures of acrophobia in the real world, and general measures of overall improvement. An objective measure of fear, electrodermal skin fluctuation, was also included during the virtual exposure to heights. Symptoms were assessed by self-report and by independent assessors at approximately 1 week and 3 months posttreatment. RESULTS: Exposure therapy combined with DCS resulted in significantly larger reductions of acrophobia symptoms on all main outcome measures. Subjects receiving DCS had significantly more improvement compared with subjects receiving placebo within the virtual environment (1 week after treatment, P</=.001; 3 months later, P</=.05). Subjects receiving DCS also showed significantly greater decreases in posttreatment skin conductance fluctuations during the virtual exposure (P</=.05). Additionally, subjects receiving DCS had significantly greater improvement compared with subjects receiving placebo on general measures of real-world acrophobia symptoms (acrophobia avoidance [P</=.02], acrophobia anxiety [P</=.01], attitudes toward heights [P</=.04], clinical global improvement [P</=.01], and number of self-exposures to real-world heights [P</=.01]); the improvement was evident early in treatment and was maintained at 3 months. CONCLUSION: These pilot data provide initial support for the use of acute dosing of DCS as an adjunct to exposure-based psychotherapy to accelerate the associative learning processes that contribute to correcting psychopathology.

Adult↗

PubMed1997

Virtual reality in endonasal surgery.

Virtual environments provide a new dimension of graphic simulation. The interaction between the human and the computer is now intuitive for the user. The use of virtual reality (VR) gives the user the feeling of participating in a (computer generated) scenario very much like reality. This feeling is an essential requirement for simulation of surgical interventions using digital data. Especially in the fields of sinus and skull-base surgery, computer assisted simulation could present a valuable and effective alternative method for honing endoscopic skills. Traditionally, surgeons gain experience through anatomic preparation and education by more experienced colleagues. Landmarks like skull base, carotid arteria or optical nerve have to be identified intraoperatively in order to orientate in this critical region. Highly sensitive structures can be damaged most easily. The quality of surgical skills can be characterized as the sum of knowledge, individual experience and manual dexterity. It is conceivable that a surgeon's level of training and experience could be significantly increased by use of VR. With this in mind, a VR-based simulator for procedures in sinus surgery will improve most of these parts. To provide the virtual environment, a realistic representation of the region of interest with all relevant anatomical structures is required. Based on data from tomographic imaging studies, a three-dimensional representation of the paranasal sinuses is semiautomatically reconstructed. Textures derived from endoscopic images are superimposed on the virtual anatomic structures and provide better realism. Two main components of the VR interface can be distinguished: the 3-D interaction to guide the surgical instruments and the 2-D graphical user interface for visual feedback and control of the session. Moreover, the 3-D interaction has to be realized by means of Virtual Reality techniques providing a simulation of an endoscope and an intuitive handling of other surgical instruments.

Computer Simulation↗

PubMed2006

Virtual reality exposure therapy: 150-degree screen to desktop PC.

Virtual reality exposure therapy (VRET) developed using immersive or semi-immersive virtual environments present a usability problem for practitioners. To meet practitioner requirements for lower cost and portability VRET programs must often be ported onto desktop environments such as the personal computer (PC). However, success of VRET has been shown to be linked to presence, and the environment's ability to evoke the same reactions and emotions as a real experience. It is generally accepted that high-end virtual environments (VEs) are more immersive than desktop PCs, but level of immersion does not always predict level of presence. This paper reports on the impact on presence of porting a therapeutic VR application for schizophrenia from the initial research environment of a semi-immersive curved screen to PC. Presence in these two environments is measured both introspectively and across a number of causal factors thought to underlie the experience of presence. Results show that the VR exposure program successfully made users feel they were "present" in both platforms. While the desktop PC achieved higher scores on presence across causal factors participants reported they felt more present in the curved screen environment. While comparison of the two groups was statistically significant for the PQ but not for the IPQ, subjective reports of experiences in the environments should be considered in future research as the success of VRET relies heavily on the emotional response of patients to the therapeutic program.

Adolescent↗

PubMed2005

Virtual reality and computer-enhanced training applied to wheeled mobility: an overview of work in Pittsburgh.

Some aspects of assistive technology can be enhanced by the application of virtual reality. Although virtual simulation offers a range of new possibilities, learning to navigate in a virtual environment is not equivalent to learning to navigate in the real world. Therefore, virtual reality simulation is advocated as a useful preparation for assessment and training within the physical environment. We are engaged in several efforts to develop virtual environments and devices for mobility skills assessment and training, exercise training, and environment assessment. Virtual reality offers wheelchair users a training tool in different risk-free environments without any indoor (e.g., walls, furniture, and stairs) and outdoor (e.g., curb cuts, uneven terrain, and street traffic) physical constraints. Virtual reality technology will probably become more common in the field of assistive technology, especially given the rapid expansion of gaming technology and the continued exponential growth of computing power.

Computer Simulation↗

PubMed2006

The role of presence in virtual reality exposure therapy.

A growing body of literature suggests that virtual reality is a successful tool for exposure therapy in the treatment of anxiety disorders. Virtual reality (VR) researchers posit the construct of presence, defined as the interpretation of an artificial stimulus as if it were real, to be a presumed factor that enables anxiety to be felt during virtual reality exposure therapy (VRE). However, a handful of empirical studies on the relation between presence and anxiety in VRE have yielded mixed findings. The current study tested the following hypotheses about the relation between presence and anxiety in VRE with a clinical sample of fearful flyers: (1) presence is related to in-session anxiety; (2) presence mediates the extent that pre-existing (pre-treatment) anxiety is experienced during exposure with VR; (3) presence is positively related to the amount of phobic elements included within the virtual environment; (4) presence is related to treatment outcome. Results supported presence as a factor that contributes to the experience of anxiety in the virtual environment as well as a relation between presence and the phobic elements, but did not support a relation between presence and treatment outcome. The study suggests that presence may be a necessary but insufficient requirement for successful VRE.

Adaptation, Psychological↗

PubMed2002

Effectiveness of virtual reality for teaching pedestrian safety.

Sixty percent to 70% of pedestrian injuries in children under the age of 10 years are the result of the child either improperly crossing intersections or dashing out in the street between intersections. The purpose of this injury prevention research study was to evaluate a desktop virtual reality (VR) program that was designed to educate and train children to safely cross intersections. Specifically, the objectives were to determine whether children can learn pedestrian safety skills while working in a virtual environment and whether pedestrian safety learning in VR transfers to real world behavior. Following focus groups with a number of key experts, a virtual city with eight interactive intersections was developed. Ninety-five children participated in a community trial from two schools (urban and suburban). Approximately half were assigned to a control group who received an unrelated VR program, and half received the pedestrian safety VR intervention. Children were identified by group and grade by colored tags on their backpacks, and actual street crossing behavior of all children was observed 1 week before and 1 week after the interventions. There was a significant change in performance after three trials with the VR intervention. Children learned safe street crossing within the virtual environment. Learning, identified as improved street-crossing behavior, transferred to real world behavior in the suburban school children but not in the urban school. The results are discussed in relation to possibilities for future VR interventions for injury prevention.

Accidents, Traffic↗

PubMed2004

Using immersive technology for postural research and rehabilitation.

Posture has traditionally been examined by isolating individual control pathways to determine their specific contributions. However, if these pathways are responsive to functional contexts, then their responses may differ when the system is receiving simultaneous inputs from multiple pathways. Thus, we may never fully understand how the central nervous system (CNS) organizes behaviors in the real world from studies conducted in the minimized environment of the laboratory. The consequence of this is that when findings from the laboratory are applied to therapeutic intervention, the intervention may not be appropriate for all circumstances and will not fully meet the needs of the patient. We have united an immersive dynamic virtual environment with motion of a posture platform to record the biomechanical and physiological responses to combined visual, vestibular, and proprioceptive inputs. The virtual environment possesses content, contrast, and texture so that we can examine postural responses as they might occur in a complex, real-world environment. In this paper we specifically describe the factors guiding our choices of virtual technology and present data from young adults, elderly adults, and an individual with bilateral labyrinthine loss to demonstrate how multimodal inputs influence their postural response organization. Significant implications for future experimental and rehabilitation protocols are also discussed.

Adult↗

PubMed2000

Material property determination of sub-surface objects in a viscoelastic environment.

Modeling human organs and soft tissue or anatomic regions for the purpose of medical training and simulation is a relatively new area. The data presented here is the groundwork for our ongoing development of a real-time haptic virtual environment for abdominal soft tissue palpation. The purpose of modeling the human abdomen is twofold. First, to provide a mathematical description of soft tissue and organs and second, to simulate the behavior of realistic interactions in real-time within a virtual environment. We have developed a, non-invasive, system that will allow us to determine mathematical functions that model the deformation of individual layers of soft tissue within the human abdomen. This system has been tested, experimentally, with a viscoelastic polyester foam model. We have been able to determine the stiffness and force/displacement function of an object beneath two layers of foam having different material characteristics. These experimental results correlate well with known polyester foam material characteristics. In general, the calculated stiffness constants were within 5% of the actual value. The data presented in this study shows that this system may be a viable tool for accurate measurement of human soft tissue properties and behavioral response to palpation.

Abdomen↗

PubMed1999

Designing a successful HMD-based experience.

For entertainment applications, a successful virtual experience based on a head-mounted display (HMD) needs to overcome some or all of the following problems: entering a virtual world is a jarring experience, people do not naturally turn their heads or talk to each other while wearing an HMD, putting on the equipment is hard, and people do not realize when the experience is over. In the Electric Garden at SIGGRAPH 97, we presented the Mad Hatter's Tea Party, a shared virtual environment experienced by more than 1,500 SIGGRAPH attendees. We addressed these HMD-related problems with a combination of back story, see-through HMDs, virtual characters, continuity of real and virtual objects, and the layout of the physical and virtual environments.

Computer Graphics↗

PubMed2004

Fear conditioning in virtual reality contexts: a new tool for the study of anxiety.

BACKGROUND: Context conditioning has been suggested to model clinical anxiety, but context, as manipulated in animal models, has not been translated to human studies. A virtual environment might prove to be the ideal tool for innovative experimental paradigms to study explicitly cued fear and contextual anxiety in humans. METHODS: Subjects were guided through a virtual environment that consisted of two rooms connected by a street scene. In each of the rooms, a blue and a yellow panel on a wall served as explicit conditioned stimuli (CS). The panels were displayed several times. One of the panels (CS+) was associated with a shock in one of the rooms (shock room). No shock was administered in the other room (safe room). Acoustic startle stimuli were administered in the presence and in the absence of the panels to assess explicit cued conditioning to the CS and context conditioning to the rooms, respectively. RESULTS: Startle was potentiated by the CS+ in both rooms, which suggests generalization of fear across contexts. After acquisition, startle was potentiated in the shock room, compared with the safe room, in the absence of the CS+. CONCLUSIONS: These results support the future use of virtual reality to design new conditioning experiments to study both fear and anxiety.

Adult↗

PubMed2004

Immersion and emotion: their impact on the sense of presence.

The present study is designed to test the role of immersion and media content in the sense of presence. Specifically, we are interested in the affective valence of the virtual environments. This paper describes an experiment that compares three immersive systems (a PC monitor, a rear projected video wall, and a head-mounted display) and two virtual environments, one involving emotional content and the other not. The purpose of the experiment was to test the interactive role of these two media characteristics (form and content). Scores on two self-report presence measurements were compared among six groups of 10 people each. The results suggest that both immersion and affective content have an impact on presence. However, immersion was more relevant for non-emotional environments than for emotional ones.

Adolescent↗

PubMed2005

Virtual reality therapy versus cognitive behavior therapy for social phobia: a preliminary controlled study.

Social phobia is one of the most frequent mental disorders and is accessible to two forms of scientifically validated treatments: anti-depressant drugs and cognitive behavior therapies (CBT). In this last case, graded exposure to feared social situations is one of the fundamental therapeutic ingredients. Virtual reality technologies are an interesting alternative to the standard exposure in social phobia, especially since studies have shown its usefulness for the fear of public speaking. This paper reports a preliminary study in which a virtual reality therapy (VRT), based on exposure to virtual environments, was used to treat social phobia. The sample consisted of 36 participants diagnosed with social phobia assigned to either VRT or a group-CBT (control condition). The virtual environments used in the treatment recreate four situations dealing with social anxiety: performance, intimacy, scrutiny, and assertiveness. With the help of the therapist, the patient learns adapted cognitions and behaviors in order to reduce anxiety in the corresponding real situations. Both treatments lasted 12 weeks, and sessions were delivered according to a treatment manual. Results showed statistically and clinically significant improvement in both conditions. The effect-sizes comparing the efficacy of VRT to the control traditional group-CBT revealed that the differences between the two treatments are trivial.

Adaptation, Psychological↗

PubMed1998

A national center for biocomputation: in search of a patient-specific interactive virtual surgery workbench.

This report describes the three-dimensional imaging and virtual environment technologies developed in NASA's Biocomputation Center for scientific purposes that have now led to applications in the field of medicine. A major goal is to develop a virtual environment surgery workbench for planning complex craniofacial and breast reconstructive surgery, and for training surgeons.

Breast Neoplasms↗