Advertisement

Medicine | IN THE LAB

Computer-generated images offer a virtual release from severe pain

August 02, 2004|Linda Marsa | Special to The Times

For people in severe pain, even maximum doses of narcotics can be inadequate -- and potentially dangerous. What such patients need, some researchers say, is a method to help control pain without using those drugs.

Their quest for such a therapy has led them to an unlikely analgesic: virtual reality.

Studies have shown that it can dull pain by distracting patients, leaving less conscious attention available to process pain signals. "Humans have a limited amount of attention, and it's hard to do two things at once," says Hunter G. Hoffman, a psychologist at the University of Washington in Seattle.

In the last few years, he and his colleagues have tested virtual reality as a pain-management tool. The results of one of their first studies -- on 12 burn patients having their bandages changed -- suggested they were onto something.

In addition to receiving painkillers, patients spent some of their time in a virtual-reality session and some playing a video game. The game had no effect. During the virtual-reality session, however, patients reported that their pain lessened an average of 40% to 50%.

"It was such a dramatic drop that it was hard to believe," says Hoffman, head of the university's Virtual Reality Analgesia Research Center. "We wondered if this was just a subjective reaction, or was there an actual physical response."

To answer this question, researchers did a second study. They used MRI scans -- and a special virtual-reality helmet that could be worn inside the scanner -- to monitor the pain centers of eight healthy volunteers' brains. Researchers attached a device to the patients' feet, subjecting them to painful bursts of heat for seven minutes at 30-second intervals. The heat was administered -- and scans were taken -- with and without virtual reality.

When the volunteers were immersed in the virtual reality world (floating through a snowy canyon, flinging snowballs at such targets as snowmen and igloos), they hardly noticed the short surges of heat on their feet. The scans showed that their brains' ability to register pain was also greatly diminished.

Participants reported that compared to the experience without virtual reality, time thinking about pain dropped 35%, pain unpleasantness decreased 36%, and the worst pain declined 23%. Physical changes were even more dramatic: The MRI scans revealed that when participants were inside the virtual-reality world, activity in five key pain centers decreased, some by as much as 97%.

"Brain scans revealed that [virtual reality] actually changed the pattern of brain activity, and the amount of pain signals that enter the brain," Hoffman says. Study results were published in June.

Generating such significant results using relatively primitive tools shows the approach's promise, says David Patterson, a psychologist at the University of Washington School of Medicine involved in the study on burn patients. Still, the cost of the technology must be reduced, and the equipment refined, before virtual reality can become a standard pain management tool.

Advertisement
Los Angeles Times Articles
|
|
|