By Becky McCall
Fantasy worlds created by virtual reality have been shown to provide a novel form of relief to patients suffering from intractable pain.
Therapy distracts the brain
Dr Hunter Hoffman, research fellow at the Harborview Medical Center in Seattle, has tested his virtual worlds on victims of burns injuries who suffer excruciating pain during their daily dressing changes which conventional drug therapy fails to control.
Hoffman's virtual worlds, which he calls by names such as SnowWorld or SpiderWorld, are designed to immerse the user so deeply in the virtual experience that their attention is distracted away from the pain.
SnowWorld, for instance, takes users on an absorbing virtual journey through glaciers and ice caves whilst having to defend themselves from attack by polar bears and penguins.
Mike Robinson, a patient who has undergone the virtual reality treatment, said it helped him to overcome the extreme discomfort he felt when his dressings were changed.
"My pain when the nurse is changing my bandages is consistently extreme," he told BBC News Online.
Immersed in a SnowWorld
"But during the time I was in VR, I was pretty much unaware that the nurse was even working on my wound.
"I mean, at some level I knew she was working on me, but I wasn't thinking about it because I was inside that SnowWorld."
Virtual analgesia is founded on the principle of distracting the attentional resources of the brain.
Dr Hoffman believes pain contains a significant psychological element which is why distracting thoughts by virtual reality lends itself so well to pain control.
"Pain requires conscious attention. Humans have a limited amount of this and it's hard to do two things at once," he said.
"In this case, we try to lure attention away from the pain signals by drawing the spotlight of attention into the virtual environment leaving less available to process incoming pain signals."
Real benefit has been gained by burns victims
The psychological component is thought to interact with the physiological, according to the prevalent idea of how pain manifests itself, known as Gate Theory.
This suggests that higher order thought processes descend the spinal cord and influence the amount of pain allowed to enter the brain.
The use of virtual reality in related conditions such as phobias and post-traumatic stress disorder (PTSD) attests to its influence of mind over matter.
Hoffman is in the process of developing a treatment programme for the survivors of the 9/11 attacks on the World Trade Center.
In collaboration with Cornell University in New York, Hoffman has built a virtual reality programme that is a simulation of the events of 9/11 designed to desensitise the patient to the events of that day.
A WTC program helps those with post-traumatic stress disorder
"With PTSD such as that suffered by the survivors of the WTC attacks, there is an avoidance component," says Dr Hoffman, whose center is attached to the University of Washington.
"Virtual 'exposure' therapy allows access to the event a step at a time, starting with getting up on the morning of September 11th and gradually working up to the most disturbing events of the memory. It is a controlled way of eliciting and processing the memories."
One patient overcame her sense of guilt at running away from the scene and failing to help others who subsequently died.
Virtual reality exposure therapy has helped return a sense of calm and acceptance to her life.