neurodudes

Neat article on how immersive VR treatment results in a significantly lower pain for severe burn victims during treatment. Click below to read the whole article.

July 26, 2004
Virtual-Reality Therapy
Patients can get relief from pain or overcome their phobias by
immersing themselves in computer-generated worlds
By Hunter G. Hoffman
http://www.sciam.com/article.cfm?
chanID=sa006&colID=1&articleID=000CDC34-D80E-10FA-89FB83414B7F0000

———-

In the science-fiction thriller The Matrix, the heroes “plugged in” to
a virtual world. While their bodies rested in reclining chairs, their
minds fought martial-arts battles, dodged bullets and drove motorcycles
in an elaborately constructed software program. 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.

At least two software companies are already leasing virtual-reality
programs and equipment to psychologists for phobia treatment in their
offices. And the Virtual Reality Medical Center, a chain of clinics in
California, has used similar programs to successfully treat more than
300 patients suffering from phobias and anxiety disorders. Although
researchers must conduct more studies to gauge the effectiveness of
these applications, it seems clear that virtual therapy offers some
very real benefits.

SpiderWorld and SnowWorld
Few experiences are more intense than the pain associated with severe
burn injuries. After surviving the initial trauma, burn patients must
endure a long journey of healing that is often as painful as the
original injury itself. Daily wound care–the gentle cleaning and
removal of dead tissue to prevent infection–can be so excruciating
that even the aggressive use of opioids (morphine-related analgesics)
cannot control the pain. The patient’s healing skin must be stretched
to preserve its elasticity, to reduce muscle atrophy and to prevent the
need for further skin grafts. At these times, most patients–and
especially children–would love to transport their minds somewhere else
while doctors and nurses treat their wounds. 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).

Pain has a strong psychological component. The same incoming pain
signal can be interpreted as more or less painful depending on what the
patient is thinking. In addition to influencing the way patients
interpret such signals, psychological factors can even influence the
amount of pain signals allowed to enter the brain’s cortex.
Neurophysiologists Ronald Melzack and Patrick D. Wall developed this
“gate control” theory of pain in the 1960s [see "The Tragedy of
Needless Pain," by Ronald Melzack; Scientific American, February 1990].

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.
The first patient had a severe burn on his leg; the second had deep
burns covering one third of his body, including his face, neck, back,
arms, hands and legs. Both had received skin-graft surgery and staples
to hold the grafts in place.

We performed the study during the removal of the staples from the skin
grafts. The boys received their usual opioid medication before
treatment. In addition, each teenager spent part of the treatment
session immersed in a virtual-reality program and an equal amount of
time playing a popular Nintendo video game (either Wave Race 64, a
jet-ski racing game, or Mario Kart 64, a race-car game). The
virtual-reality program, called SpiderWorld, had originally been
developed as a tool to overcome spider phobias; we used it for this
investigation because it was the most distracting program available at
the time and because we knew it would not induce nausea. Wearing a
stereoscopic, position-tracked headset that presented three-dimensional
computer graphics, the patients experienced the illusion of wandering
through a kitchen, complete with countertops, a window and cabinets
that could be opened. An image of a tarantula was set inside the
virtual kitchen; the illusion was enhanced by suspending a furry spider
toy with wiggly legs above the patient’s bed so that he could actually
feel the virtual spider.

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.

Why is virtual reality so effective in alleviating pain? Human
attention has been likened to a spotlight, allowing us to select some
information to process and to ignore everything else, because there is
a limit to how many sources of information we can handle at one time.
While a patient is engaged in a virtual-reality program, the spotlight
of his or her attention is no longer focused on the wound and the pain
but drawn into the virtual world. Because less attention is available
to process incoming pain signals, patients often experience dramatic
drops in how much pain they feel and spend much less time thinking
about their pain during wound care.

To increase the effectiveness of the virtual therapy, our team created
SnowWorld, a program specifically customized for use with burn patients
during wound care. Developed with funding from Microsoft co-founder
Paul G. Allen and the National Institutes of Health, SnowWorld produces
the illusion of flying through an icy canyon with a frigid river and
waterfall, as snowflakes drift down [see illustration on pages 58 and
59]. Because patients often report that they are reliving their
original burn experience during wound care, we designed a glacial
landscape to help put out the fire. As patients glide through the
virtual canyon, they can shoot snowballs at snowmen, igloos, robots and
penguins standing on narrow ice shelves or floating in the river. When
hit by a snowball, the snowmen and igloos disappear in a puff of
powder, the penguins flip upside down with a quack, and the robots
collapse into a heap of metal.

More recent research has shown that the benefits of virtual-reality
therapy are not limited to burn patients. We conducted a study
involving 22 healthy volunteers, each of whom had a blood pressure cuff
tightly wrapped around one arm for 10 minutes. Every two minutes the
subjects rated the pain from the cuff; as expected, the discomfort rose
as the session wore on. But during the last two minutes, each of the
subjects participated in two brief virtual-reality programs,
SpiderWorld and ChocolateWorld. (In ChocolateWorld, users see a virtual
chocolate bar that is linked through a position sensor to an actual
candy bar; as you eat the real chocolate bar, bite marks appear on the
virtual bar as well.) The subjects reported that their pain dropped
dramatically during the virtual-reality session.

What is more, improving the quality of the virtual-reality system
increases the amount of pain reduction. In another study, 39 healthy
volunteers received a thermal pain stimulus–delivered by an
electrically heated element applied to the right foot, at a preapproved
temperature individually tailored to each participant–for 30 seconds.
During this stimulus, 20 of the subjects experienced the fully
interactive version of SnowWorld with a high-quality headset, sound
effects and head tracking. The other 19 subjects saw a stripped-down
program with a low-quality, see-through helmet, no sound effects, no
head tracking and no ability to shoot snowballs. We found a significant
positive correlation between the potency of the illusion–how strongly
the subjects felt they were immersed in the virtual world–and the
alleviation of their pain.

Seeing Pain in the Brain
Of course, all these studies relied on the subjective evaluation of
the pain by the patients. As a stricter test of whether virtual reality
reduces pain, I set out with my colleagues at the University of
Washington–including Todd L. Richards, Aric R. Bills, Barbara A. Coda
and Sam Sharar–to measure pain-related brain activity using functional
magnetic resonance imaging (fMRI). Healthy volunteers underwent a brain
scan while receiving brief pain stimulation through an electrically
heated element applied to the foot. When the volunteers received the
thermal stimuli without the distraction of virtual reality, they
reported severe pain intensity and unpleasantness and spent most of the
time thinking about their pain. And, as expected, their fMRI scans
showed a large increase in pain-related activity in five regions of the
brain that are known to be involved in the perception of pain: the
insula, the thalamus, the primary and secondary somatosensory cortex,
and the affective division of the anterior cingulate cortex [see
illustration on page 61].

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.

Encouraged by our results, two large regional burn centers–the
William Randolph Hearst Burn Center at New York Weill Cornell Medical
Center and Shriners Hospital for Children in Galveston, Tex.–are both
making preparations to explore the use of SnowWorld for pain control
during wound care for severe burns. Furthermore, the Hearst Burn
Center, directed by Roger W. Yurt, is helping to fund the development
of a new upgrade, SuperSnowWorld, which will feature lifelike human
avatars that will interact with the patient. SuperSnowWorld will allow
two people to enter the same virtual world; for example, a burn patient
and his mother would be able to see each other’s avatars and work
together to defeat monstrous virtual insects and animated sea creatures
rising from the icy river. By maximizing the illusion and
interactivity, the program will help patients focus their attention on
the virtual world during particularly long and painful wound care
sessions. Now being built by Ari Hollander, an affiliate of HITLab,
SuperSnowWorld will be offered to medical centers free of charge by the
Hearst and Harborview burn centers.

Virtual-reality analgesia also has the potential to reduce patient
discomfort during other medical procedures. Bruce Thomas and Emily
Steele of the University of South Australia have found that virtual
reality can alleviate pain in cerebral palsy patients during physical
therapy after muscle and tendon surgery. (Aimed at improving the
patient’s ability to walk, this therapy involves exercises to stretch
and strengthen the leg muscles.) Our team at the University of
Washington is exploring the clinical use of virtual reality during a
painful urological procedure called a rigid cystoscopy. And we have
conducted a study showing that virtual reality can even relieve the
pain and fear of dental work.

Fighting Fear
Another therapeutic application of virtual reality is combating
phobias by exposing patients to graphic simulations of their greatest
fears. This form of therapy was introduced in the 1990s by Barbara O.
Rothbaum of Emory University and Larry F. Hodges, now at the University
of North Carolina at Charlotte, for treating fear of heights, fear of
flying in airplanes, fear of public speaking, and chronic
post-traumatic stress disorder in Vietnam War veterans. Like the
pain-control programs, exposure therapy helps to change the way people
think, behave and interpret information.

Working with Albert Carlin of HITLab and Azucena Garcia-Palacios of
Jaume I University in Spain (a HITLab affiliate), our team has shown
that virtual-reality exposure therapy is very effective for reducing
spider phobia. Our first spider-phobia patient, nicknamed Miss Muffet,
had suffered from this anxiety disorder for nearly 20 years and had
acquired a number of obsessive-compulsive behaviors. She routinely
fumigated her car with smoke and pesticides to get rid of spiders.
Every night she sealed all her bedroom windows with duct tape after
scanning the room for spiders. She searched for the arachnids wherever
she went and avoided walkways where she might find one. After washing
her clothes, she immediately sealed them inside a plastic bag to make
sure they remained free of spiders. Over the years her condition grew
worse. When her fear made her hesitant to leave home, she finally
sought therapy.

Like other kinds of exposure therapy, the virtual-reality treatment
involves introducing the phobic person to the feared object or
situation a little at a time. Bit by bit the fear decreases, and the
patient becomes more comfortable. In our first sessions, the patient
sees a virtual tarantula in a virtual kitchen and approaches as close
as possible to the arachnid while using a handheld joystick to navigate
through the three-dimensional scene. The goal is to come within arm’s
reach of the virtual spider.

During the following sessions, the participant wears a glove that
tracks the position of his or her hand, enabling the software to create
an image of a hand–the cyberhand–that can move through the virtual
kitchen. The patient maneuvers the cyberhand to touch the virtual
spider, which is programmed to respond by making a brief noise and
fleeing a few inches. The patient then picks up a virtual vase with the
cyberhand; when the patient lets go, the vase remains in midair, but an
animated spider with wiggling legs comes out. The spider drifts to the
floor of the virtual kitchen, accompanied by a brief sound effect from
the classic horror movie Psycho. Participants repeat each task until
they report little anxiety. Then they move on to the next challenge.
The final therapy sessions add tactile feedback to the virtual
experience: a toy spider with an electromagnetic position sensor is
suspended in front of the patient, allowing him or her to feel the
furry object while touching the virtual spider with the cyberhand.

After only 10 one-hour sessions, Miss Muffet’s fear of spiders was
greatly reduced, and her obsessive-compulsive behaviors also went away.
Her success was unusually dramatic: after treatment, she was able to
hold a live tarantula (which crawled partway up her arm) for several
minutes with little anxiety. In a subsequent controlled study of 23
patients diagnosed with clinical phobia, 83 percent reported a
significant decrease in their fear of spiders. Before treatment, these
patients could not go within 10 feet of a caged tarantula without high
anxiety; after the virtual-reality therapy, most of them could walk
right up to the cage and touch its lid with only moderate anxiety. Some
patients could even remove the lid.

Similar programs can be incorporated into the treatment of a more
serious psychological problem: post-traumatic stress disorder. The
symptoms of PTSD include flashbacks of a traumatic event, intense
reactions to anything symbolizing or resembling the event, avoidance
behaviors, emotional numbing, and irritability. It is a debilitating
disorder that affects the patient’s social life and job performance and
is much more challenging to treat than specific phobias. Cognitive
behavioral therapy protocols, such as the prolonged exposure therapy
developed by University of Pennsylvania psychologist Edna Foa, have a
high success rate for patients with PTSD. The exposure therapy is
thought to work by helping patients process and eventually reduce the
emotions associated with the memories of the traumatic event. The
therapist gradually exposes the patient to stimuli that activate these
emotions and teaches the patient how to manage the unwanted responses.

Researchers are now exploring whether virtual-reality programs can be
used to standardize the therapy and improve the outcome for patients,
especially those who do not respond to traditional methods. JoAnn
Difede of Cornell University and I developed a virtual-reality exposure
therapy to treat a young woman who was at the World Trade Center during
the September 11 attacks and later developed PTSD. During the therapy,
the patient put on a virtual-reality helmet that showed virtual jets
flying over the towers and crashing into them with animated explosions
and sound effects. Although the progress of the therapy was gradual and
systematic, the scenes presented by the software in the final sessions
were gruesomely realistic, with images of people jumping from the
burning buildings and the sounds of sirens and screams. These stimuli
can help patients retrieve memories of the event and, with the guidance
of a therapist, lower the discomfort of remembering what happened.

Our first patient showed a large and stable reduction in her PTSD
symptoms and depression after the virtual-reality sessions. Other
patients traumatized by the tower attacks are now being treated with
virtual-reality therapy at Weill Cornell Medical College and New York
Presbyterian Hospital. I am also collaborating with a team of
researchers led by Patrice L. (Tamar) Weiss of Haifa University in
Israel and Garcia-Palacios to create a virtual-reality treatment for
survivors of terrorist bombings who develop PTSD.

Virtual Reality by the Hour
Because dozens of studies have established the efficacy of
virtual-reality therapy for treating specific phobias, this is one of
the first medical applications to make the leap to widespread clinical
use. Virtually Better, a Decatur, Ga.based company that was co-founded
by virtual-reality pioneers Hodges and Rothbaum, has produced programs
designed to treat an array of anxiety disorders, including fear of
heights, fear of flying and fear of public speaking. The company is
leasing its software to psychologists and psychiatrists for $400 a
month, allowing therapists to administer the treatments in their own
offices. A Spanish firm called Previ offers similar programs. Instead
of reclining on a couch, patients interactively confront their fears by
riding in virtual airplanes or by standing in front of virtual
audiences.

In contrast, more research is needed to determine whether virtual
reality can enhance the treatment of PTSD. Scientists have not yet
completed any randomized, controlled studies testing the effectiveness
of virtual-reality therapy for treating the disorder. But some of the
leading PTSD experts are beginning to explore the virtues of the
technology, and the preliminary results are encouraging.

Large clinical trials are also needed to determine the value of
virtual-reality analgesia for burn patients. So far the research has
shown that the SnowWorld program poses little risk and few side
effects. Because the patients use SnowWorld in addition to traditional
opioid medication, the subjects who see no benefit from virtual reality
are essentially no worse off than if they did not try it. Virtual
reality may eventually help to reduce reliance on opioids and allow
more aggressive wound care and physical therapy, which would speed up
recovery and cut medical costs. The high-quality virtual-reality
systems that we recommend for treating extreme pain are very expensive,
but we are optimistic that breakthroughs in display technologies over
the next few years will lower the cost of the headsets. Furthermore,
patients undergoing less painful procedures, such as dental work, can
use cheaper, commercially available systems. (Phobia patients can also
use the less expensive headsets.)

The illusions produced by these programs are nowhere near as
sophisticated as the world portrayed in the Matrix films. Yet virtual
reality has matured enough so that it can be used to help people
control their pain and overcome their fears and traumatic memories. And
as the technology continues to advance, we can expect even more
remarkable applications in the years to come.

HUNTER G. HOFFMAN is director of the Virtual Reality Analgesia Research
Center at the University of Washington Human Interface Technology
Laboratory (HITLab) in Seattle. He is also an affiliate faculty member
in the departments of radiology and psychology at the University of
Washington School of Medicine. He joined the HITLab in 1993 after
earning his Ph.D. in cognitive psychology at the University of
Washington. To maximize the effectiveness of virtual reality in
reducing physical and psychological suffering, he is exploring ways to
enhance the illusion of going inside a computer-generated virtual
world.

This entry was posted on Tuesday, August 3rd, 2004 at 7:39 am by Neville Sanjana and is filed under Medicine. You can follow any responses to this entry through the RSS 2.0 feed. You can skip to the end and leave a response. Pinging is currently not allowed.