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At least 811 records · Page 45Linked to original sources

PubMed2006

[Clinical and communication simulation workshop for fellows in gastroenterology: the trainees' perspective].

BACKGROUND: The continuing development in computer-based medical simulators provides an ideal platform for simulator-assisted training programs for medical trainees. Computer-based endoscopic simulators provide a virtual reality environment for training endoscopic procedures. This study illustrates the use of a comprehensive training model combining the use of endoscopic simulators with simulated (actor) patients (SP). AIM: To evaluate the effectiveness of a comprehensive simulation workshop from the trainee perspective. METHODS: Four case studies were developed with emphasis on communication skills. Three workshops with 10 fellows in each were conducted. During each workshop the trainees spent half of the time in SP case studies and the remaining half working with computerized endoscopic simulators with continuous guidance by an expert endoscopist. Questionnaires were completed by the fellows at the end of the workshop. RESULTS: Seventy percent of the fellows felt that the endoscopic simulator was close or very close to reality for gastroscopy and 63% for colonoscopy. Eighty eight percent thought the close guidance was important for the learning process with the simulator. Eighty percent felt that the case studies were an important learning experience for risk management. CONCLUSION: Further evaluation of multi-modality simulation workshops in gastroenterologist training is needed to identify how best to incorporate this form of instruction into training for gastroenterologists.

Computer-Assisted Instruction↗

PubMed1995

Modeling respiratory anatomy and physiology in VR.

In trauma, many injuries impact anatomical structures, which may in turn affect physiological processes--not only those processes within the structures, but ones occurring in physical proximity to them as well. Our goal is to endow a 3D anatomical model with physiological mechanisms to demonstrate such effects. Our approach couples deformable object simulation for organs with physiological modeling, in a way that supports three-dimensional animated simulation. We demonstrate our approach through our current model of respiratory mechanics in a virtual 3D environment. Anatomical models that can capture physiological and pathophysiological changes can serve as an infrastructure for more detailed modeling, as well as benefiting surgical planning, surgical training, and general medical education.

Computer Simulation↗

PubMed1997

Intraocular pressure in inbred mouse strains.

PURPOSE: To develop a protocol to measure the intraocular pressure (IOP) of living mice and to determine the IOP of genetically different mouse strains. METHODS: Eyes of anesthetized animals were cannulated with a very fine fluid-filled glass microneedle. The microneedle was connected to a pressure transducer, and the pressure signal was analyzed with a computer system. Intraocular pressures of male C3H/He iota, C57BL/ 6 iota, A/iota, and BALB/c iota mice were determined. RESULTS: Differences in IOP were detected between genetically distinct mouse strains maintained in virtually identical environments. C3H/He iota was the strain with the highest average IOP (13.7 +/- 0.8 mm Hg). This strain average was 1.4 mm Hg higher than that for C57BL/6 iota (12.3 +/- 0.5 mm Hg; P = 0.14), 4.3 mm Hg higher than that for A/iota (9.4 +/- 0.5 mm Hg; P < 0.001), and 6 mm Hg higher than that for BALB/c iota (7.7 +/- 0.5 mm Hg; P < 0.001). CONCLUSIONS: The authors have developed an accurate and reliable procedure for measuring intraocular pressure in living mice. This procedure can detect IOP differences between groups of mice that differ by genotype.

Animals↗

PubMed1997

Environmental knowledge is subserved by separable dorsal/ventral neural areas.

Environmental psychology models propose that knowledge of large-scale space is stored as distinct landmark (place appearance) and survey (place position) information. Studies of brain-damaged patients suffering from "topographical disorientation" tentatively support this proposal. In order to determine if the components of psychologically derived models of environmental representation are realized as distinct functional, neuroanatomical regions, a functional magnetic resonance imaging (fMRI) study of environmental knowledge was performed. During scanning, subjects made judgments regarding the appearance and position of familiar locations within a virtual reality environment. The fMRI data were analyzed in a manner that has been empirically demonstrated to rigorously control type I error and provide optimum sensitivity, allowing meaningful results in the single subject. A direct comparison of the survey position and landmark appearance conditions revealed a dorsal/ventral dissociation in three of four subjects. These results are discussed in the context of the observed forms of topographical disorientation and are found to be in good agreement with the human lesion studies. This experiment confirms that environmental knowledge is not represented by a unitary system but is instead functionally distributed across the neocortex.

Adult↗

PubMed1998

Robot-aided functional imaging: application to a motor learning study.

The purpose of this study was to examine the neural activity underlying an implicit motor learning task. In particular, our goals were to determine whether initial phases of procedural learning of a motor task involve areas of the brain distinct from those involved in later phases of learning the task, and what changes in neural activity coincide with performance improvement. We describe a novel integration of robotic technology with functional brain imaging and its use in this study of implicit motor learning. A portable robotic device was used to generate forces that disturbed the subjects' arm movements, thereby generating a "virtual mechanical environment" that the subjects learned to manipulate. Positron emission tomography (PET) was used to measure indices of neural activity underlying learning of the motor task. Eight health, right-handed male subjects participated in the study. Results support the hypothesis that different stages of implicit learning (early and late implicit learning) occur in an orderly fashion, and that distinct neural structures may be involved in these different stages. In particular, neuroimaging results indicate that the cortico-striatal loop may play a significant role during early learning, and that the cortico-cerebellar loop may play a significant role during late learning.

Adult↗

PubMed2000

Arbor 3D: an interactive environment for examining phylogenetic and taxonomic trees in multiple dimensions.

UNLABELLED: This paper examines a new technique for the visualization of and the interaction with trees, objects frequently used to convey hierarchical relationships in biological data. Motivated by the quality of 2D tree interaction, we adapt the planar tree-of-life metaphor to a virtual, semi-immersive 3D environment. A 3D environment extends the utility of this metaphor by allowing the user to view an entire data set in a single screen. Interrogation of the tree is implemented using 3D input devices. This real-time interrogation of the tree itself provides a quick means by which to qualitatively analyse the hierarchical data. In this paper, we describe the techniques underlying the implementation of such an environment. We conclude by considering the utility of tree metaphors as a basis for the representation of highly dimensional data sets. AVAILABILITY: Arbor3D (source code, a binary executable for SGI IRIX 6.4, Perl parsers, and sample Newick data files) are available via the Internet (http://xian.tamu.edu/Arbor3D/). Arbor3D can be displayed in "CAVE simulator" mode on an SGI workstation screen, or as an interactive virtual environment on a projection workbench. CONTACT: druths@rice.edu; echen@cs.rice.edu; leland@xian.tamu.edu

Classification↗

PubMed2006

Virtual reality immersion method of distraction to control experimental ischemic pain.

BACKGROUND: Virtual reality immersion has been advocated as a new effective adjunct to drugs for pain control. The attenuation of pain perception and unpleasantness has been attributed to the patient's attention being diverted from the real, external environment through immersion in a virtual environment transmitted by an interactive 3-D software computer program via a VR helmet. OBJECTIVES: To investigate whether VR immersion can extend the amount of time subjects can tolerate ischemic tourniquet pain. METHODS: The study group comprised 20 healthy adult volunteers. The pain was induced by an inflated blood pressure cuff during two separate, counterbalanced, randomized experimental conditions for each subject: one with VR and the control without VR exposure. The VR equipment consisted of a standard computer, a lightweight helmet and an interactive software game. RESULTS: Tolerance time to ischemia was significantly longer for VR conditions than for those without (P < 0.001). Visual Analogue Scale (0-10) ratings were recorded for pain intensity, pain unpleasantness, and the time spent thinking about pain. Affective distress ratings of unpleasantness and of time spent thinking about pain were significantly lower during VR as compared with the control condition (P< 0.003 and 0.001 respectively). CONCLUSIONS: The VR method in pain control was shown to be beneficial. The relatively inexpensive equipment will facilitate the use of VR immersion in clinical situations. Future research is necessary to establish the optimal selection of clinical patients appropriate for VR pain therapy and the type of software required according to age, gender, personality, and cultural factors.

Adult↗

PubMed2006

A preliminary report on the use of virtual reality technology to elicit craving and cue reactivity in cocaine dependent individuals.

In the present feasibility study, we developed a 3-dimensional virtual "crack" cocaine environment and evaluated the environment's ability to elicit subjective craving and cue reactivity (i.e., subjective emotional responding, heart rate and skin conductance) in 11 crack cocaine dependent individuals. Each of the seven 3-D crack cocaine scenes in the cocaine environment depicted actors engaging in a range of using-related behaviors (i.e., smoking crack) whereas the neutral environment contained scenes depicted 3-D aquariums with active aquatic life (baseline measures were obtained following immersion in the neutral environment). Results indicated that craving was significantly elevated during the cocaine-related scenes as compared to baseline. Craving varied by scene content, with scenes depicting active cocaine use eliciting the highest levels of craving. Heart rate was significantly higher in four of the scenes with drug use content and positive affect (i.e., happiness) ratings were significantly lower during cocaine scenes as compared to baseline. Overall, the results suggest that a standardized and stimulus rich virtual reality environment effectively elicits craving and physiologic reactivity. Such technology has potential utility in the development and refinement of exposure-based behavioral and pharmacological interventions for substance use disorders.

Adult↗

PubMed1996

Virtual design prototyping applied to medical facilities.

Over the past five years, MITRE has developed rapid 3D modeling and immersive environment capabilities that supports the application of virtual environment technology to many traditional and non-traditional domains [1]. This paper provides background information on these capabilities and describes the application of this technology to the experimental design prototyping of operating rooms of the future and to the design and retrofit of existing or proposed medical facilities. These capabilities employ contemporary commercial hardware and software and exploit stereoscopic projection displays and headsets. A unique user interface facilitates object manipulation within these immersive environments and addresses two key areas: 1) Visualization of the contents on the model server or library in a catalog form; and 2) Natural interaction and immersion of the user with the visualized catalog and selected visualized objects in a 3D synthetic environment. A brief discussion of two developing applications of this technology will be presented. In one application example, the modeling environment can be used to synthesize physical replicas (potentially full stereo scale) of actual surgical rooms used for training of medical personnel. Alternatively, it can be employed as the infrastructure for a new form of collaborative interactive visualization, namely, telesurgery. In another example, the rapid modeling capability provides designers, architects and medical personnel with a means of rapidly developing synthetic renderings of (potentially interactive and remotely operative) proposed medical facilities prior to construction. We also discuss key issues needing to be resolved for successful model interchange.

Computer Simulation↗

PubMed2002

Using virtual reality technology for aircraft visual inspection training: presence and comparison studies.

The aircraft maintenance industry is a complex system consisting of several interrelated human and machine components. Recognizing this, the Federal Aviation Administration (FAA) has pursued human factors related research. In the maintenance arena the research has focused on the aircraft inspection process and the aircraft inspector. Training has been identified as the primary intervention strategy to improve the quality and reliability of aircraft inspection. If training is to be successful, it is critical that we provide aircraft inspectors with appropriate training tools and environment. In response to this need, the paper outlines the development of a virtual reality (VR) system for aircraft inspection training. VR has generated much excitement but little formal proof that it is useful. However, since VR interfaces are difficult and expensive to build, the computer graphics community needs to be able to predict which applications will benefit from VR. To address this important issue, this research measured the degree of immersion and presence felt by subjects in a virtual environment simulator. Specifically, it conducted two controlled studies using the VR system developed for visual inspection task of an aft-cargo bay at the VR Lab of Clemson University. Beyond assembling the visual inspection virtual environment, a significant goal of this project was to explore subjective presence as it affects task performance. The results of this study indicated that the system scored high on the issues related to the degree of presence felt by the subjects. As a next logical step, this study, then, compared VR to an existing PC-based aircraft inspection simulator. The results showed that the VR system was better and preferred over the PC-based training tool.

Adult↗

PubMed2002

[Clinical aspects of a virtual operating room for the prediction of operative interventions in some disease of the middle ear].

Clinical aspects of creating a software system for simulation and prediction of operative interventions and hearing function changes are considered. The system will make simulation and prediction transparent and convenient for the user. The technical challenge is to create mediation languages which enforce rigorous mathematical computation while supporting intuitive behaviour. The prevalent textual interface of command lines and pull-down menus is replaced by physical behaviour within an environment. The system is based on new possibilities of computer-integrated environments for problem solving such as virtual environments and it will be presented in a form of a virtual operating room. The following aspects are taken into consideration: a model of the middle ear, database for existing methods of operative interventions, x-ray and computed tomography imaging of the temporal bone, determination and localization of otosclerosis foci, modeling and determination of acoustic parameters for transplantation materials, simulation and prognosis of potential complications.

Ear, Middle↗

PubMed2004

The influence of virtual reality on playfulness in children with cerebral palsy: a pilot study.

The purpose of this paper was to examine the effects of virtual play intervention on the level of playfulness of children with cerebral palsy. Thirteen children aged 8-13 years comprised the study group. Children attended eight one-hour virtual reality play sessions in which they were immersed and interacted with virtual reality. The Test of Playfulness (TOP) was used as the measure to assess playfulness. Participants were videotaped while they played during 12 different environments over the course of their intervention time. Three randomly selected virtual reality play sessions were chosen to score three different virtual reality environments within each session yielding a total of nine trials (environments) for each participant. The types of virtual environments varied across participants. Overall, the different virtual reality play environments produced varying levels of playfulness according to the TOP's four different subscale scores. Motivation ranged from 1.50 to 2.25, internal control ranged from 1.00 to 1.88, suspension of reality ranged from 0 to 0.26, and framing ranged from 1.33 to 1.78. The three environments producing the highest playfulness ratings were called Paint, Trip and Island Sounds. These environments allowed creativity, persistence with the task, pleasure, and a certain degree of control. Two environments did not appear to foster playfulness. A possible reason was that these environments were too unpredictable and frustrating for participants. These results will be useful for creating new virtual reality software applications that will encourage playfulness in children with disabilities.

Cerebral Palsy↗

PubMed2006

The promise of a virtual lab in drug discovery.

To date, the life sciences 'omics' revolution has not lived up to the expectation of boosting the drug discovery process. The major obstacle is dealing with the volume and diversity of data generated. An enhanced-science (e-science) approach based on remote collaboration, reuse of data and methods, and supported by a virtual laboratory (VL) environment promises to get the drug discovery process afloat. The creation, use and preservation of information in formalized knowledge spaces is essential to the e-science approach. VLs include Grid computation and data communication as well as generic and domain-specific tools and methods for information management, knowledge extraction and data analysis. Problem-solving environments (PSEs) are the domain-specific experimental environments of VLs. Thus, VL-PSEs can support virtual organizations, based on the changing partnerships characteristic of successful drug discovery enterprises.

Computer Simulation↗

PubMed2003

Gravity and spatial orientation in virtual 3D-mazes.

In order to bring new insights into the processing of 3D spatial information, we conducted experiments on the capacity of human subjects to memorize 3D-structured environments, such as buildings with several floors or the potentially complex 3D structure of an orbital space station. We had subjects move passively in one of two different exploration modes, through a visual virtual environment that consisted of a series of connected tunnels. In upright displacement, self-rotation when going around corners in the tunnels was limited to yaw rotations. For horizontal translations, subjects faced forward in the direction of motion. When moving up or down through vertical segments of the 3D tunnels, however, subjects facing the tunnel wall, remaining upright as if moving up and down in a glass elevator. In the unconstrained displacement mode, subjects would appear to climb or dive face-forward when moving vertically; thus, in this mode subjects could experience visual flow consistent with rotations about any of the 3 canonical axes. In a previous experiment, subjects were asked to determine whether a static, outside view of a test tunnel corresponded or not to the tunnel through which they had just passed. Results showed that performance was better on this task for the upright than for the unconstrained displacement mode; i.e. when subjects remained "upright" with respect to the virtual environment as defined by subject's posture in the first segment. This effect suggests that gravity may provide a key reference frame used in the shift between egocentric and allocentric representations of the 3D virtual world. To check whether it is the polarizing effects of gravity that leads to the favoring of the upright displacement mode, the experimental paradigm was adapted for orbital flight and performed by cosmonauts onboard the International Space Station. For these flight experiments the previous recognition task was replaced by a computerized reconstruction task, which proved to be more efficient in terms of the time required to achieve reliable results. Suppressing gravity did not immediately affect relative performance between the two modes, indicating that on-line graviceptor information is not directly responsible for this differential effect. Trends in the evolution of responses over the course of a 10-day mission, however, suggest that human subjects might adapt their ability to represent internally complex 3D displacements.

Gravitation↗

PubMed1995

Virtually-augmented interfaces for tactical aircraft.

The term Fusion Interface is defined as a class of interface which integrally incorporates both virtual and non-virtual concepts and devices across the visual, auditory and haptic sensory modalities. A fusion interface is a multi-sensory virtually-augmented synthetic environment. A new facility has been developed within the Human Engineering Division of the Armstrong Laboratory dedicated to exploratory development of fusion-interface concepts. One of the virtual concepts to be investigated in the Fusion Interfaces for Tactical Environments facility (FITE) is the application of EEG and other physiological measures for virtual control of functions within the flight environment. FITE is a specialized flight simulator which allows efficient concept development through the use of rapid prototyping followed by direct experience of new fusion concepts. The FITE facility also supports evaluation of fusion concepts by operational fighter pilots in a high fidelity simulated air combat environment. The facility was utilized by a multi-disciplinary team composed of operational pilots, human-factors engineers, electronics engineers, computer scientists, and experimental psychologists to prototype and evaluate the first multi-sensory, virtually-augmented cockpit. The cockpit employed LCD-based head-down displays, a helmet-mounted display, three-dimensionally localized audio displays, and a haptic display. This paper will endeavor to describe the FITE facility architecture, some of the characteristics of the FITE virtual display and control devices, and the potential application of EEG and other physiological measures within the FITE facility.

Aerospace Medicine↗

PubMed2005

The Edinburgh Electronic Veterinary Curriculum: an online program-wide learning and support environment for veterinary education.

The Edinburgh Electronic Veterinary Curriculum (EEVeC) is a purpose-built virtual learning support environment for the veterinary medicine program at the University of Edinburgh. It is Web based and adapted from a system developed for the human medical curriculum. It is built around a set of databases and learning objects and incorporates features such as course materials, personalized timetables, staff and student contact pages, a notice board, and discussion forums. The EEVeC also contains global or generic resources such as information on quality enhancement and research options. Many of these features contribute to the aim of building a learning community, but a challenge has been to introduce specific features that enhance student learning. One of these is a searchable lecture database in which learning activities such as quizzes and computer-aided learning exercises (CALs) can be embedded to supplement a synopsis of the lecture and address the key needs of integration and reinforcement of learning. Statistics of use indicate extensive student activity during evenings and weekends, with a pattern of increased usage over the years as more features become available and staff and students progressively engage with the system. An essential feature of EEVeC is its flexibility and the way in which it is evolving to meet the changing needs of the teaching program.

Curriculum↗

PubMed2004

Active navigation and orientation-free spatial representations.

In this study, we examined the orientation dependency of spatial representations following various learning conditions. We assessed the spatial representations of human participants after they had learned a complex spatial layout via map learning, via navigating within a real environment, or via navigating through a virtual simulation of that environment. Performances were compared between conditions involving (1) multiple- versus single-body orientation, (2) active versus passive learning, and (3) high versus low levels of proprioceptive information. Following learning, the participants were required to produce directional judgments to target landmarks. Results showed that the participants developed orientation-specific spatial representations following map learning and passive learning, as indicated by better performance when tested from the initial learning orientation. These results suggest that neither the number of vantage points nor the level of proprioceptive information experienced are determining factors; rather, it is the active aspect of direct navigation that leads to the development of orientation-free representations.

Adolescent↗

PubMed2002

Panic and agoraphobia in a virtual world.

Virtual reality (VR) offers a great new perspective on what it can offer an individual. These new approaches can give an individual the immersion and cognitive guidance that they need to help overcome his or her disorder. VR differs from the traditional displays in computer graphics as these various displays are integrated to give the user a sense of presence or immersion in the virtual world. To more effectively treat panic and agoraphobic patients using VR, it is necessary to determine the physiological responses of nonphobics when placed in the virtual panic and agoraphobia environments. This study exposed nonphobic participants to virtual panic and agoraphobia worlds with a program entitled "Virtual Medicine." Individuals without a diagnosis of panic and agoraphobia, as confirmed by intake and self-report questionnaires, were exposed to four different VR environments (elevator, supermarket, town square, and beach). During these VR experiences, physiology was measured by noninvasive sensors (peripheral skin temperature, heart rate, heart rate variability, respiration, and skin conductance). These measurements were compared to baseline physiology, which was recorded for five min prior to the VR exposure. These levels of physiological arousal will be useful in comparing against the phobic responses during virtual exposure. It will be useful to explore differences between immersion, physiological responses, and self-report responses in nonphobics versus phobics.

Adult↗