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Last Updated: Tuesday, 14 November 2006, 10:29 GMT
3D system 'moves' phantom limbs
The computer program
The computer program allows patients to move their lost limbs
A computer program has been designed to allow amputees to see and move a 3D "phantom limb".

A small study by researchers at the University of Manchester found the device could help people with phantom limb pain.

Previous research showed that if a person's brain is "tricked" into believing they can see and move a "phantom limb", pain can decrease.

The researchers say one patient saw her pain ease after just one session.

It is suggested that phantom limb pain is caused by signals from nerve endings on the amputated limb being amplified.

'Positive impact'

People with phantom limb pain are currently treated using a "mirror box" where they move their remaining arm, but their brain perceives it is their amputated limb is actually the one moving.

However, it is easy for the illusion to be broken and the benefit to be lost.

The Manchester researchers created a virtual reality world where patients can see both "limbs" moving at once.

Upper-limb amputees were fitted with a special data glove and had sensors attached to the elbow and wrist joints.

Sensors were fitted to the knee and ankle joints of lower-limb amputees.

Participant using the system
One theory is that the brain is being tricked
Dr Craig Murray, University of Manchester

Patients can use their remaining limb to control the movements of the computer-generated limb which appears in the 3D computer-generated "virtual world".

They are able to move fingers, arms, hand, arms, feet and legs. They are even able to play ball games.

Three men and two women aged 56-65 took part in the study.

There were three arm amputees and two leg amputees, who had lost limbs between the ages of one and 40.

Each used the system between seven and 10 times over two to three months.

Four out of the five reported improvement in their phantom limb pain, sometimes almost immediately.

Dr Craig Murray, of the School of Psychological Sciences who led the research, said: "Although there isn't compete agreement on how phantom limb pain is helped by the mirror box or our virtual reality system, one theory is that the brain is being tricked."

He added: "One patient felt that the fingers of her amputated hand were continually clenched into her palm, which was very painful for her.

"However, after just one session using the virtual system she began to feel movement in her fingers and the pain began to ease."

Dr Stephen Pettifer, of the University's School of Computer Science, said: "Most people know about 3D graphics and virtual reality from their use in the entertainment industry, in computer games and special effects in films.

"It's very satisfying being able apply the same technology to something that may have a real positive impact on someone's health and well-being."

Academics now hope to carry out a larger study to identify people most likely to benefit from the research.

How the brain feels false limbs
01 Jul 04 |  Health
Feeling lost limbs
31 May 00 |  Health

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