Virtual Reality Offers Exciting Possibilities for Pain Management

During their Thursday session, titled “Virtual Reality and Pain Management,” at the American Pain Society 29th Annual Scientific Meeting, moderator Jeffrey Gold, PhD, and presenters Sean Mackey, MD, PhD; Lynnda Dahlquist, PhD; David Patterson, PhD, ABPP; and Dave Thomas, PhD, discussed the use of “immersive virtual reality” (VR) as an effective tool not only for distracting children during acute procedures, but also for the management of recurrent or cronic pain.

Jeffrey Gold, PhD, associate professor of anesthesiology and pediatrics, director of the Pediatric Pain Management Clinic at Childrens Hospital Los Angeles, began the session by asking “What is virtual reality?” He defined this “novel intervention” as an “immersive attention-grabbing gaming environment” that is often delivered in head mounted display that includes head tracking technology. Virtual reality has beenused successfully in the treatment of a variety of phobias and anxiety disorders, including PTSD, eating disorders, autism, and substance abuse. Although there is a robust and growing literature on the topic of virtual reality in healthcare (Gold noted that there are nearly 3,000 articles on ths topic in PubMed), there is a relative dearth of studies on the subject of virtual reality and pain management (only 100 search results on PubMed articles for VR and pain; only 50 for VR and adult pain). Gold noted that there has been especially promising studies on the use of VR as part of burn wound care and VR used in conjunction with hypnosis and biofeedback.

fMRI and the brain's response to pain

Sean Mackey,MD, PhD, associate professor in the department of Anesthesiology, Division of Pain Management and Neurosciences, Stanford University, and director of the Stanford Systems Neuroscience and Pain Lab (SNAPL), discussed the development and application of fMRI technology and the insights this is providing into the brain’s response to pain. “The primary goal of neuropharmacology and neurostimulation is to attain control over specific neural processes,” Mackey said. So the question for researchers is whether people can learn to control specific localised processes that occur in the brain, and if so how can this be applied to pain management? Mackey noted that there are “multiple factors that contribute to patient’s overall perceptin of pain, and that the amount of pain patients are experiencing often has little to do with the amount of nociception they experience.”

He reviewed data from studies conducted using the Stanford real-time fMRI system (“Brainview”) by the Systems Neuroscience and Pain Lab. Using fMRI to image discrete regions of activation in the brain, researchers sought to monitor specific regions of the brain involved with pain perception and learn whether patients could be taught to control those regions in such a way as to decrease the intensity of pain they were perceiving. Mackey reported that after multiple repeated training sessions, subjects were in fact able to voluntarily control activity in specific pain-perceiving areas of the brain. This led to durable benefits in patients, as seen by a reduction in pain questionnaire scores that measured intensity of pain. This process of real-time brain connectivity modulation holds great promise, and Mackey said that future research goals will be for scientists to determine which brain illnesses are most likely to respond to this form of control, to integrate fMRI with VR interventions,a nd to determine how long these benefits last.

Beating pain at its own game

Lynnda Dahlquist, PhD, professor in the Departmetn of Psychology, University of Maryland School of Medicine, spoke about using videogame and VR technology for acute pain management in children. She described several successful applications of immersive VR technology to use as a distraction for children during acute procedures (the programs have names like “Snow World,” “Virtual Gorilla,” and “Street Luge”).

The successful use of VR in this capacity led researchers to look at whether VR-assisted distraction could be an effective acute pain maagement strategy for children. Dahlquist said that existing studies in tis area suffer from several limitations -- many studies have small sample sizes; too many focus on demonstrating that VR works (VR vs. standard care) creating a need for more studies that examine VR vs. other forms of disrtaction; and the studies use a wide range of VR technology, which makes it difficult to compare results across studies.

But, if VR can be used effectively as a pain management strategy, Dahlquist said that it will be important to determine what aspects of VR are essential to its effectiveness. “How important is the interaction with the virtual environment?” Dahlquist asked. In one study she referenced, children either watched someone else play a video game or actually played the game themselves. Both methods increased pain threshhold and tolerance, but there was a more dramatic increase with interactive distraction. “The interactive aspect of VR-assisted videogame distraction appears to be crucial,” said Dahlquist.

Another study used a helmet-mounted VR game. Some of the participating children played the game (a languid underwater simulation called “Free Dive”) with the helmet, some played it without the helmet. Again, both methods improved pain threshhold and tolerance, but researchers noted greater improvement in the children who wore the helmet. Interestingly, older kids experienced greater increases in pain threhold and tolerance; kids younger than 10 experienced little change.

So researchers, conducted another study using a better helmet and a faster-paced videogame. They still didn’t see a differential response to the helmet in younger children, which means, said Dahlquist, that this technology may not be as suitable for younger children (under age 10) as it is for adults and older kids. “Age is definitely a mdoerator for response to VR,” noted Dahlquist.

Yet another study looked at whether preschool kids show the same response to active and passive distraction as older kids. This one used videogames that were developmentally appropriate for pre-schoolers, and produced similar results as the other studies -- both interactive and passive distraction resulted in comparablelevels of improvement. However, age did not relate to kids’ responses to passive distraction, but did with interactive distraction. This prompted researchers to examine executive functions in relation to responses to interactive distraction. They found that children under age four had little response to the interactive stimulation.

Dahlquist noted that because the effects of VR are not consistent across children of different ages, and are also not consistent across technologies and virtual environments, further research is needed in order to optimize the application of this technology as part of a pain management strategy in children.

The future of virtual reality technology in pain management

David Patterson, PhD, professor in the Department of Rehabilitation Medicine at the University of Washington School of Medicine, and co-creator of SnowWorld, presented compelling data on the integration of VR technology and hypnosis in the treatment of acute pain. Patterson noted that hypnosis has been successfully used to treat pain in a variety of setings, but that it “takes a lot of clinical training to get good hypnosis results,” so incorporating VR technology offers exciting possibilities for producing similar results without the training. VR hypnosis is also cost-effective, with one study showing that adding hypnosis to standard sedation cuts medication costs in half.

Dave Thomas, PhD, health science administrator at the National Institute of Drug Abuse, Division of Basic Neuroscience and Behavioral Research, Behavioral and Cognitive Science Research Branch, closed the session by noting that we are just scratching the surface with the current applications of VR for pain management. Studies show direct modulation of the human brain pain responses with VR. The key to VR’s success, said Thomas, is that “much of pain is in the brain.” He said that “most of perception, including pain, is in your brain; perception is inference,” and that it’s possible that a significant percentage of information is just “made up” by your brain — it takes in a realtively small amount of information and extrapolates the rest. It amy turn out that “your brain is just guessing” a lot of the time, said Thomas. Most perception “may be based on a little sensory input and then the brain guessing and filling in the rest,” thus VR may work by “tricking” the brain.