by Mark Hodges
From the moment the Vietnam War vet dons the head-mounted display and enters the Virtual Vietnam landing zone, it's clear why this 3D immersive simulation has such strong potential for treating people suffering from post-traumatic stress.
The visual rendering of the virtual battlefield and surrounding jungle looks like a cartoon, but the sounds of radio chatter, shouts, rifle shots, and helicopter wings are all too real. Add to that the vibration felt in the standing platform after each mortar explosion, and it's no wonder some veterans move quickly for protective cover.
|Vietnam veterans suffering from post-traumatic stress disorder can relive the sights and sounds of their combat experiences in the Virtual Vietnam landing zone simulation. Research shows that the treatments work for those with moderate PTSD symptoms. |
"People are taken a bit by surprise," says Ken Graap, chief executive officer of Virtually Better, the Atlanta-based company that developed Virtual Vietnam. "They think it's cartoonish, but then they get in there and have a reaction. With the sound effects, it's quite convincing."
Virtual Vietnam is one example in a widening range of virtual environments developed over the past five years for assessing and treating phobias, other psychological disorders, excessive pain, and brain injuries that impair cognitive functioning. Most of this work is still the province of research laboratories, but fledgling companies such as Virtually Better are starting to market VR systems.
Six years ago, a $250,000 Silicon Graphics workstation was required to run a virtual reality module for treating fear of heights. Today, Virtually Better uses a Pentium computer with stereo sound, a standing platform, and a VFX 3D head-mounted display with a built-in tracker that together cost less than $5000, while charging customers a fee of $400 per month for two years to license the company's proprietary software for treating post-combat stress disorder, fear of flying, and fear of heights. The price tag for VR is fast becoming affordable for many clinicians. The question now is how many of them will embrace technology in their day-to-day work.
Virtual reality offers a blend of attractive attributes for cognitive psychologists. The most basic of these is its ability to create a 3D simulation of reality that can be explored by patients. In many virtual environments, the graphic renderings of people and objects are quite simple, but they are still able to give the visitor a strong sense of presence-the illusion of being in a real place.
In conventional therapy, psychologists treat simple phobias by asking patients to imagine their fears or by taking them into real situations that frighten them. Each approach has its strengths: The first requires no special staging and can take place in the privacy of a clinician's office, while gradual exposure to a real source of fear more viscerally arouses the typical patient's emotions. Virtual reality simulations provide the advantages of both approaches-patients can go into vivid computer-generated worlds that they perceive as real, yet they do so in safety and privacy.
Besides verisimilitude, virtual environments allow psychologists to offer therapeutically useful features not available in the real world, says Albert A. "Skip" Rizzo, a cognitive psychologist at the University of Southern California's Integrated Media Systems Center. For example, a virtual world can provide patients with different sorts of cues, such as a disembodied voice giving instructions or a directional arrow hovering in mid-air.
Another of virtual reality's attractions is its consistency: A clinical psychologist can apply a precise stimulus repeatedly and measure the patient's response. But the technology also is flexible enough that patients with divergent needs can use the same module in different ways, without having to rebuild the system.
The most significant attraction of VR, though, is evidence that it works well in assessing and treating a variety of psychological disorders. Such studies have not yet used large populations of test subjects, but research conducted with a wide range of small experimental groups has garnered positive results.
Brenda Wiederhold, a cognitive psychologist at the Center for Advanced Multimedia Psychotherapy (San Diego, CA) says that the use of VR in phobia treatment is already attaining success rates of 90 percent. In the case of Virtual Vietnam, researchers at the Veterans Administration Medical Center in Atlanta have eased the anxiety of veterans whose post-traumatic stress disorder symptoms are in the middle range of severity. David Ready, a staff psychologist and project director, says that 13 of 20 participating veterans have satisfactorily completed the therapy in 8 to 20 sessions.
Some observers have expressed concerns that patients would become dizzy or nauseated after extended immersion in a virtual environment, but studies are finding little incidence of cybersickness among test subjects. Indeed, Wiederhold maintains that patients appear to like VR-based treatment and push their therapists to use it. "They want VR and are disappointed when they don't get it in the first session," she says. "This is not just some fad."
The most popular early uses of VR in psychology have involved gradual exposure of phobic patients to the sources of their fears. Virtual environments of this kind were pioneered by the developers of Virtual Vietnam-Larry Hodges, an associate professor of computing at Georgia Tech, and Barbara Rothbaum, an assistant professor of psychiatry at Emory University in Atlanta. In 1994, Hodges and Rothbaum performed the first controlled study of fear of heights, designing an immersive 3D simulator powered by a Silicon Graphics workstation that took visitors into the elevator of a virtual hotel.
After establishing the promise of the acrophobia simulation with a small group of patients, Hodges and Rothbaum developed a VR-based treatment for people with a fear of flying. Patients using this training module enter a virtual airliner that looks, sounds, and moves like a jet about to take off. As the plane leaves the airport, the patient sits in his or her seat, feeling the sensations of movement and watching the changing view outside the window as the plane climbs into the air.
|A treatment for spider phobia, SpiderWorld lets users see and touch a virtual spider in a 3D kitchen. The virtual environment is also used to distract burn victims from pain during wound dressing changes.|
A more recent project by Hodges' and Rothbaum's research group has resulted in a training module that helps people overcome the fear of public speaking. These simulations are being marketed by Virtually Better, which was established to commercialize the researchers' work.
Phobic reactions aren't the only problems for which cognitive psychologists are developing VR training modules. At the University of Washington, researchers at the Human Interface Technology Laboratory have built virtual environments that distract burn victims from their pain during physical therapy and daily wound dressing changes. These modules are intended to supplement but not replace traditional pharmacological painkillers. In studies to date, experimental subjects have worn a head-mounted display that takes them into SpiderWorld, a virtual environment in which the visitor can see and touch a tarantula in a 3D kitchen.
Project leader Hunter Hoffman cites one study of 12 burn victims who underwent three minutes of physical therapy immersed in SpiderWorld and three minutes without distractions. All of the patients said that the therapy exercises were less painful when they were in the virtual world, and cumulatively estimated their pain to be diminished from 60 to 14 on a scale of 100.
Sponsored by the Paul Allen Foundation and the National Institutes of Health, the work of Hoffman and colleagues, including David R. Patterson, a clinical psychologist at the University of Washington, is now aimed at building more elaborate virtual environments. The first of these modules will be SnowWorld, an icy 3D canyon with a river that patients can see and hear running running along the bottom. Patients can fly through the canyon and fire snowballs at snowmen and igloos. The use of cold imagery may help to offset the "heat" of burn victims' pain, but Hoffman believes that the illusion of presence in another world is more likely responsible for the relief felt by patients.
|In SnowWorld, visitors fly through an icy 3D canyon and shoot snowballs at snowmen and igloos. Like SpiderWorld, it is being used to distract burn victims during dressing changes. |
Hoffman's team runs its SnowWorld simulations on an SGI Octane and is evaluating several NT platforms. Software tools employed for development of the virtual environments include MultiGen-Paradigm's Creator for modeling and its VEGA program for building and running the world.
Diagnosing patients with attention disorders has been difficult because the tests used to assess these behaviors don't replicate real-world conditions effectively. Now, virtual reality assessment tools are being developed so that neuropsychologists can detect and categorize conditions such as attention deficit hyperactivity disorder (ADHD), traumatic brain injury, and neurodegenerative conditions such as Alzheimer's disease and vascular dementia. VR may even be useful for the rehabilitation of persons with attention problems.
Skip Rizzo and his colleagues at the University of Southern California Integrated Media Systems Center have built a virtual classroom in which they can assess the reaction time to simple learning tasks by children suffering from ADHD. This virtual environment uses a Virtual Research V8 head-mounted display as well as an Ascension Technology head, hand, and tracking device and runs on an SGI Onyx platform.
In the assessment module, children find themselves in a graphically rendered classroom looking at a teacher in front of a blackboard. They watch a series of letter combinations flash on a blackboard and hit a response button whenever a certain sequence appears. In another exercise, they listen to the teacher talk while objects flash on the blackboard behind her. If the object that the teacher describes appears on the blackboard, the student hits the response button. Distractions-such as people walking in the hall, cars passing on the road, even paper airplanes flying through the air-are introduced as students go through these exercises.
Rizzo says that an initial test involving seven children from ages 6 to 12 provided "encouraging results" about the usability of the virtual classroom. He and his colleagues will soon mount a clinical trial to assess 15 ADHD children from ages 8 to 12 as well as a 15-member control group. Rizzo's group at USC has built a similar virtual office for assessing the attention skills of older patients who have suffered traumatic brain injuries (TBI).
|In a virtual classroom designed to assess attention deficit disorders, students are asked to identify letter sequences amid distractions such as paper airplanes and passing cars. |
Rizzo hopes that USC will soon license this technology to a company. The product would be a Windows-based system that offers a common graphical user interface for a variety of therapeutic scenarios. Because of recent reductions in the cost of high-performance computers, Rizzo believes that the cost for such a system would be around $8000 to $10,000.
A victim of a traumatic brain injury (TBI) often loses basic life skills and struggles through extensive rehabilitation to regain them. Cognitive psychologists are developing VR-based training modules that can assess how much these skills have deteriorated and provide a safe environment in which to practice them. The tedious, repetitive rehabilitation for TBI patients often overtaxes human caregivers, but a virtual environment offers each patient the opportunity to practice a task the same way every time.
"You would be amazed at how much complexity there is in making a peanut butter and jelly sandwich," says Charles Christiansen, dean of the University of Texas Medical Branch in Galveston. "We take so much of our daily behavior for granted."
Since 1994, Christiansen has led a research effort to determine how effective virtual reality is as a tool to assess the extent of brain injuries and provide patients with environments where they can relearn basic skills. Christiansen's group has teamed with Lincom Corp. of Houston to develop Softhaven, a virtual environment created with Superscape software for basic life skills training. Softhaven runs on a 486 PC platform with a sound card and head-mounted 3D display glasses that expose users to video images and stereo sound.
|This virtual kitchen environment is used to help victims of traumatic brain injury re-learn simple tasks, such as a 30-step sequence for heating canned soup.|
They have developed a virtual kitchen in which subjects can relearn basic food preparation, such as making soup from a can, a task taking 30 steps. The patient uses a mouse or joystick to move about the kitchen and views the kitchen on a regular computer monitor with special 3D glasses. In a recent experiment, 30 victims of TBI practiced soup preparation and were rated on their ability to perform each step. The results showed that patients attain comparable success rates using the virtual kitchen and standard training.
In a project aimed at assessing the skills of brain-injured adults, Maria T. Schultheis, a clinical neuropsychologist with Kessler Medical Rehabilitation Research and Education Corp., is collaborating with Northeastern University engineer Ronald Mourant to develop a virtual environment to evaluate an individual's ability to drive an automobile. With funding from the National Institute of Disability and Rehabilitation Research, Schultheis and Mourant have begun a program to develop a VR-based driving-assessment system. "There are some VR [driver] training systems already out there," Schultheis says. "We want to examine the validity of this approach, in particular with cognitive impaired individuals."
She and Mourant are developing three 15- to 20-minute immersive VR scenarios to be used on a PC-based system. The first is analogous to the driving evaluation now used by Kessler in conventional driving assessments of brain-injured persons. The second scenario will assess the person's ability for night driving. The third will add more driving complexity than can be included in the standard assessment because of safety concerns. The VR modules are being programmed with Java 3D and will run on a Gateway computer with dual Pentium III processors. The head-mounted display has not yet been selected, but an InterSense IS-300 Precision Head Tracker will be used.
One of the rationales for this project is that there are only a few certified driving-assessment programs in the country, most of them at large rehabilitation centers. The cost of maintaining them is high because of the need to purchase and maintain a vehicle, buy insurance, and employ trained evaluators. "From a patient's point of view, driving assessments are typically not covered by insurance," she says. "The cost out of pocket can range from $150 to $300 for the initial evaluation." If a VR module could be used to perform assessments at a comparable level of performance, she says, then these evaluations and training might be less costly and therefore more accessible.
VR training also has shown preliminary promise for stimulating memory retention in victims of amnesia and vascular brain injury. In a recent study, a research group from the University of East London in the United Kingdom used a non-immersive 3D virtual environment to help an amnesiac learn routes in a rehabilitation unit at Homer ton Hospital in London. The group, led by psychologists Barbara M. Brooks and F. David Rose, helped an amnesia patient learn two routes in the hospital with the aid of a 15-minute training session administered every weekday for three weeks. After this training regimen ended, the patient was able to follow these routes in the hospital and retain the knowledge for the remainder of the study, despite receiving no further training. In follow-up training, the same patient practiced finding two different routes-one in the virtual environment and the other in the real hospital. After two weeks, she had learned the route that she practiced in VR but not the one that she learned in the real world. The researchers believe that the effectiveness of the virtual environment in training may be due to the patient's ability to practice the route repeatedly and without distractions.
Victims of eating disorders often suffer from a mismatch between their appearance and their sense of how their bodies look. Thus, psychological therapies focus on helping patients change their perceptions about their appearance. Some researchers believe that these therapies could be enhanced by taking patients into virtual environments where they become more detached from their physical bodies and may be more ready to change inaccurate or negative body images.
A research group led by Giuseppe Riva of the Instituto Auxologico Italiano in Verbania, Italy, has developed a virtual environment that helps patients examine their eating patterns and assess their actual and ideal body image. The re searchers used the VR module in conjunction with an established method of cognitive therapy to help overcome the denial and resistance of patients. Riva's team conducted preliminary clinical trials of 25 patients suffering from binge-eating disorders in one study and 18 obese patients in a second study.
The virtual environment in Riva's simulator was implemented on a Pentium III-based immersive VR system known as the Thunder 500/C and developed by Virtual Engineering of Milano, Italy. It uses a Digilens head-mounted display and a two-button joystick device for navigation. The module was authored with Superscape software.
The virtual environment contains rooms with different foods and drinks, and patients are asked to touch those they wish to consume. The caloric intake of each is registered, and a virtual scale shows patients their new weights based on eating choices. In another room, patients are asked to choose between seven different figures that define a broad spectrum of different body weights. They select their ideal size as well as what they consider to be their actual size. In another room, patients see pictures of models of different sizes and examine a depiction of their actual bodies in a virtual mirror. After looking into this mirror, they walk through a long corridor and leave by choosing the door that fits their width and height.
The research is preliminary, but Riva and his colleagues have reported that binge eaters going through the VR-based experiential cognitive therapy showed reduced body dissatisfaction, while becoming more socially active and relying less on clothing that disguised their bodies.
Virtual reality therapy has shown potential for a wide range of therapies, but it is not for everyone. Unstable veterans were excluded from the Veterans Administration studies of Virtual Vietnam, because of fears that they would have adverse reactions to immersion in the environment. Ken Graap of Virtually Better extends the exclusionary list to people with high blood pressure and those suffering from delusional psychosis. Maria Schultheis also notes that brain injury victims, who suffer a variety of cognitive, perceptual, and behavioral difficulties, may have trouble considering a virtual environment real.
Beyond these limits, broader acceptance of VR among clinicians is likely to depend on more evidence of its therapeutic effectiveness. Researchers in the field are unanimous in their view that detailed, large-subject studies are needed that examine the efficacy of virtual environments in therapy. Moreover, even with such evidence, further cost reductions also may be necessary for clinicians to use virtual environments.
|Researchers warn that virtual therapy may not be appropriate for some patients. Unstable veterans, for example, are excluded from Virtual Vietnam because they may have adverse reactions to the environment.|
Wiederhold of the Center for Advanced Multimedia Psychotherapy thinks that a $15,000 price tag is too high for many practitioners and that one promising vehicle for delivering less expensive VR training could be the Internet. If this is the case, then Web-based therapy may require some form of immersiveness for many disorders. David Ready of the Veterans Administration Medical Center strongly believes that immersion in a virtual world would do a better job of engaging patients than a module using simple 2D screens.
Researchers believe that better graphical fidelity, more flexible tracking, and the ability to insert more human-like avatars into scenes will improve virtual environments over the next few years. In any case, the prerequisite for success, according to both Hodges of Georgia Tech and Wiederhold, is for a broad range of people to be involved in the design of these environments-from computer scientists to psychologists to the patients themselves. In this way, they say, virtual technologies will have the best chance to meet the needs of patients. Mark Hodges is a contributing editor of Computer Graphics World.Ascension Technology
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