A treatment using mirrors to trick the brain into healing pain is being developed by researchers.
The research is funded by the Arthritis Research Campaign
It is based on a theory where the brain's image of the body becomes faulty, causing pain.
Looking at a reflection of a healthy hand could help people ease symptoms of persistent pain, say the scientists.
The findings by the University of Bath and the Royal National Hospital for Rheumatic Diseases researchers appear in the journal Clinical Medicine.
The researchers asked a number of patients with the debilitating condition called complex regional pain syndrome to carry out routine exercises in front of a mirror.
More than half experienced pain relief during and after the exercise and further investigations showed that even greater improvements could be achieved if the tasks were practiced beforehand.
"By using a mirror reflection of a normal limb to convince the brain that everything is alright, we have found that we can correct this imbalance and help alleviate pain in complex regional pain syndrome," said Dr Candy McCabe who works in the University of Bath's School for Health and the Royal National Hospital for Rheumatic Diseases.
"In most cases normal awareness and experience of our limbs is often based on the predicted state rather than the actual state.
"When the two do not match we think sensations are generated to alert the body that things are not as it thought - rather like an early warning mechanism. If the discrepancy is very large then pain may be experienced, as pain is the body's ultimate warning mechanism.
"We think that this system may be responsible for a range of disorders where patients feel pain for apparently no clinical reason.
"Somehow the brain's image of the body differs from what it senses. When the patient moves their hand, foot or limb, they experience pain as a result."
The research is funded by the Arthritis Research Campaign.