A VR experience, such as Snow World pictured here, helps lessen anxiety and pain for patients.

For sheer magnitude and persistence of pain, it is hard to beat burn wounds. From the moment the injury begins, through the immediate hospital treatment and continuing to the long-term treatment of dressing changes, debridement, and skin grafts, a patient can look forward to long bouts with pain of varying intensity. Even the simple act of cleaning and redressing a burn wound can cause patients to experience intense anxiety, because of the pain the treatment causes.

While local anesthetics are commonly applied during these treatments, they are frequently inadequate. But what about the portion of that pain that is created and enhanced through the patients’ anxiety? If that anxiety could be lessened, would the treatment experience be more bearable for burn wound patients?

Real Pain, Virtual Distraction

Dave Patterson, PhD, a researcher at the University of Washington, is investigating whether virtual reality technology can be used to help patients take their minds off the treatment they are undergoing and thus lessen the anxiety and the pain. Doctor Patterson has received funding through the National Institutes of Health to work with pain in burn patients since 1989. He discovered VR technology when he began working with colleague Hunter Hoffman, PhD, a cognitive psychologist in the Human Interface and Technology Laboratory at the University of Washington. Dr Hoffman had been working with immersive VR as applied to pain since the early 1990s. The two published their first paper on VR and pain in the journal Painin 2000.

Since then, Drs Patterson and Hoffman have completed several studies where they used immersive VR technology as a distraction during burn wound treatment. During these studies, patients generally were treated for 3 minutes while using immersive VR technology, and then 3 minutes without it. Following painful treatment procedures, patients are asked to rate their pain using a graphic scale that looks at pain intensity. Ratings are taken immediately following procedures, and after some time has passed in order to get a sense of ongoing discomfort.

The results of their studies have continually shown that patients who use VR during their treatment sessions experience significantly less pain, and that the decrease did not fade with repeated VR use. When subjects using VR during treatment were examined using fMRI, pain-related brain activity was found to be significantly reduced.

Snow World

What are patients experiencing in this VR world? Our world is called Snow World, and is composed of a 3-D snowy, icy canyon with a river flowing at its bottom,” explained Dr Patterson when he was contacted via e-mail. “The participant can shoot at igloos, snowmen, penguins, and woolly mammoths, and the targets generally explode into an array of colors. It is a visually pleasing, nonviolent environment.”

The choice of snow as the simulation’s primary characteristic serves two purposes. The snowy landscape helps minimize simulator sickness because it is so simple, and the falling snowflakes provide a needed depth to the simulation. Also, snow is the opposite of fire, and provides a certain amount of psychological calming for the patient. This pleasing environment created by the simulation is in drastic contrast to the environment of the hospital room and the treatment, which can be severely unpleasant for patients.

“In standard care at most major burn centers, patients receive daily wound care. Dressings and bandages are removed, wounds are cleaned and debrided, and then antimicrobial agents are placed on the wounds and they are redressed,” Dr Patterson explained. “Such dressing changes are reported to be more painful than sustaining the burn injury itself. Our approach is to place patients in the virtual environment while they are undergoing the painful procedure.”

“In our studies published from the previous NIH grant cycles, we have shown that immersive virtual reality shows dramatic drops in procedural pain from burn injury care,” Dr Patterson added. “Children and adolescents seem to do particularly well, but adults also respond to the treatment.” Controlled clinical studies of the system have shown reductions in pain intensity between 35% and 50%. Previous studies have also shown that the VR distraction even works on burn patients who had their burn wounds debrided and dressed while partially submerged in a hydrotherapy tank.

In the Mind

Patients who have undergone immersive VR report large reductions in the time they spent thinking about their wound during treatment procedures. This could partially account for the decrease in experienced pain. “[Stress, depression and anticipatory anxiety] all play a big role in pain experience, however, anticipatory anxiety is a critical variable,” Dr Patterson explained. “Particularly with children, anticipatory anxiety is such a crucial issue that it often is not clear whether the issue is one of pain or anxiety. In one of our studies, we demonstrated that giving anti-anxiety agents before wound care is an effective means of reducing pain.”

VR keeps patients occupied, keeps them from focusing on the pain and on the wound, and even keeps them from looking at the wound. In studies comparing immersive VR with standard video games, it was the immersive VR that resulted in the greater pain reduction. That the standard video game allowed patients to look at their wound while it was being treated was cited as a contributing factor to its limited success.

Pain catastrophizing is another serious factor in how a patient experiences pain during treatment, Dr Patterson explained. “There is a good body of literature that indicates that people cope less well with pain if they ‘catastrophize’ about it,” he said. “Catastrophizing suggests that people think the worst about pain, or other issues. So when such a person experiences pain, they may have thoughts such as ‘This pain will never get better’ or ‘I am going to die.’”

Dr. Hoffman is quick to point out though that pain does not just exist in the mind, but also in the brain as well. The fMRI results clearly indicate a reduction in the pain signals being processed by the brain when a patient is using the VR system. “Humans have a limited amount of attention,” Dr Hoffman explained. “VR is unusually attention grabbing, and appears to be able to compete with pain for the human’s attention, leaving less attention available to process signals coming into the brain from pain receptors in the burn wound.”“Our brain scans show that VR is not just changing the way patients interpret incoming pain signals, VR is reducing the amount of pain that is even processed by the brain,” he added.

The mechanism by which VR reduces pain is one of the ongoing research topics that Drs. Patterson and Hoffman are examining. They have recently completed a several year grant cycle with NIH and are looking forward to beginning a new one. A new study set to begin this summer will focus on the use of VR with children undergoing particularly painful physical burn therapy at two or three burn centers across the country.