Tuesday, August 10, 2004

Virtual-Reality Therapy in the News

The August 2004 issue of Scientific American contains an article on Virtual-Reality Therapy.  Although the method is not ready for widespread use, it does appear that some practitioners are finding ways to make it useful.  Some of the applications are not what one might expect.  Sure, helping people get over fear of heights, or spiders, or public speaking -- those are fairly obvious.  But the researchers have found some success in treatment of pain and PTSD. 

Virtual-Reality Therapy
Patients can get relief from pain or overcome their phobias by immersing themselves in computer-generated worlds
By Hunter G. Hoffman

[...] This cardinal virtue of virtual reality--the ability to give users the sense that they are "somewhere else"--can be of great value in a medical setting. Researchers are finding that some of the best applications of the software focus on therapy rather than entertainment. In essence, virtual reality can ease pain, both physical and psychological.

For the past several years, I have worked with David R. Patterson, a pain expert at the University of Washington School of Medicine, to determine whether severely burned patients, who often face unbearable pain, can relieve their discomfort by engaging in a virtual-reality program during wound treatment. The results have been so promising that a few hospitals are now preparing to explore the use of virtual reality as a tool for pain control. In other projects, my colleagues and I are using virtual-reality applications to help phobic patients overcome their irrational fear of spiders and to treat post-traumatic stress disorder (PTSD) in survivors of terrorist attacks.

[...] Working with the staff at Harborview Burn Center in Seattle, Patterson and I set out in 1996 to determine whether immersive virtual-reality techniques could be used to distract patients from their pain. The team members include Sam R. Sharar, Mark Jensen and Rob Sweet of the University of Washington School of Medicine, Gretchen J. Carrougher of Harborview Burn Center and Thomas Furness of the University of Washington Human Interface Technology Laboratory (HITLab).

University of Washington © HUNTER G. HOFFMAN
Click for full-size image

[...] Introducing a distraction -- for example, by having the patient listen to music--has long been known to help reduce pain for some people. Because virtual reality is a uniquely effective new form of distraction, it makes an ideal candidate for pain control. To test this notion, we studied two teenage boys who had suffered gasoline burns.

[...] Both teenagers reported severe to excruciating pain while they were playing the Nintendo games but noted large drops in pain while immersed in SpiderWorld. (They rated the pain on a zero to 100 scale immediately after each treatment session.) Although Nintendo can hold a healthy player's attention for a long time, the illusion of going inside the two-dimensional video game was found to be much weaker than the illusion of going into virtual reality. A follow-up study involving 12 patients at Harborview Burn Center confirmed the results: patients using traditional pain control (opioids alone) said the pain was more than twice as severe compared with when they were inside SpiderWorld.

I took out a lot of the details of the treatment.  To explain, SpiderWorld is a virtual-reality space that originally had been developed to help people undergo desensitization to fear of spiders.  At first glance, it seems odd to use a virtual spider world to treat pain.  But it appears that the crucial therapeutic element is the immersiveness of the virtual reality world,  The content may not be as important as the verisimilitude.  THe researchers then created SnowWorld, thinking that perhaps the simulation of a frigid environment would be more effective that an ordinary house with spiders in it.  Oddly, the article does not tell us if SnowWorld turned out to be more effective than SpiderWorld.  They do inform us that the quality of the reproduction of virtual reality is important.  Highly realistic images and sounds are better than Commodore-64 style AV effects.  

Of interest to neuroscientists, the researchers then conducted fMRI studies to visualize activity of various parts of the brain.  They found that the subject reports of pain relief were correlated with objective changes in brain functioning:

[...] Creating virtual-reality goggles that could be placed inside the fMRI machine was a challenge. We had to develop a fiber-optic headset constructed of nonferrous, nonconducting materials that would not be affected by the powerful magnetic fields inside the fMRI tube. But the payoff was gratifying: we found that when the volunteers engaged in SnowWorld during the thermal stimuli, the pain-related activity in their brains decreased significantly (and they also reported large reductions in subjective pain ratings). The fMRI results suggest that virtual reality is not just changing the way patients interpret incoming pain signals; the programs actually reduce the amount of pain-related brain activity. [...]

(See the prior CC  post for background information about fMRI)

Personally, I find the notion of using computers to do psychotherapy to be a little odd.  I suspect, though, that a more details study would find that the mature of the relationship between therapist and patient still would be important.  That is, I do not think it will be possible for people to go down to Best Buy, get a computer DVD, and start curing themselves.  Maybe a simple phobia could be treated like that, but not something serious, like pain, or PTSD.  Certainly, there would be some serious ethical issues involved in making and marketing such a product. 

The reason is that desensitization seems like an obvious way to treat a phobia.  In actual practice, though, the apparent simplicity is deceptive.  Performed incorrectly, a clumsy attempt at desensitization actually can make the problem worse.  The take home message: don't try this at home.

This is especially true in the case of PTSD.  In the final part of the Sciam article, they review some early -- and encouraging -- studies of the use of virtual-reality therapy to treat persons with PTSD.  The patients they selected were victims of single, extreme traumatic events.  In the average therapy office, though, it is much more common to se patients would have sustained multiple such events over a period of years.  It is doubtful that the results for the first patient group could be generalized to imply that the second group would benefit.  Indeed, the treatment could pose much greater risks with the survivors of multiple traumata.  

Even with these cautions in mind, it is exciting to see that progress is being made in this area.  PTSD remains a common, serious problem;  the current treatment options are too limited. 

(see prior CC post  for background on PTSD.)