Virtual reality helps newly disabled learn to live with amputations

From New Scientist:

What is the best way to for someone to get used to their artificial limb? Put them in a virtual environment.

So says Anthony Steed, a computer scientist at University College London, who has been studying how the rubber hand illusion works in virtual worlds.

In the standard illusion, a false hand is placed on a table in front of a volunteer whose real hand is out of view, and both are stroked at the same time. After a while people feel a sensation in the rubber hand, even when it is the only one being touched. Steed has now discovered that people relate to virtual appendages so strongly that much of the set-up work normally needed to pull off the illusion is unnecessary in virtual environments. For example, people automatically experience ownership of their virtual limbs, without needing simultaneous stroking in the real world, claims Steed.

Twenty volunteers were asked to play simple games in a virtual environment that gave a real-world perspective in which the avatar's hands were represented as if they were the volunteer's own. The volunteers were hooked up to a monitoring system which recorded the movements of muscles and nerve-endings firing. At a random point in the game, a lamp on the virtual table toppled onto the volunteer, and their reactions were monitored. Most made gestures with their arm suggesting they were trying to move it out of the way - despite there being no real risk. In a follow-up questionnaire, volunteers acknowledged they had behaved as if the virtual hand were their own, Steed reports.

When they repeated the experiment using an arrow to represent the arm, there was no empathic response. "The strength of the rubber hand illusion depends critically on the representation of the hand," says Steed.

The experiments suggest virtual reality may be helpful for people learning to use a prosthetic limb, says Kristina Caudle at the Brain Imaging Lab at Dartmouth College, Hanover, New Hampshire. Getting accustomed to moving and feeling ownership of a virtual limb might make it easier for an amputee to accept their prosthetic limb. She believes that human-like movement, as opposed to appearance, is the key for virtual limbs. "A human-like arm that couldn't bend any finger or arm joints would be much less likely to engender the rubber hand illusion."

Steed will present his work at the Virtual Reality 2010 conference in Waltham, Massachusetts, later this month.