London, March 20 : A Tamil Nadu born leading neurologist in America, V. S. Ramachandran, says that amputees who experience phantom limb pain may find some relief by paying more attention to the people around them, something that may give them a 'virtual massage'.
Ramachandran, the Director of the Center for Brain and Cognition at the University of California, San Diego (UCSD), says that he discovered this cure while working with combat veterans.
Phantom limbs occur when an amputee feels the often-painful sensation of touch arising from a limb that is no longer present.
Ramachandran, an alumnus of Madras-based Stanley Medical College, says that his treatment makes use of the newly discovered properties of mirror neurons that fire when a person performs an intentional action like waving, and also when one observes someone else performing the same action.
"You also find cells like this for touch. They fire when you touch yourself and when you watch someone else being touched in the same location," New Scientist magazine quoted him as saying.
In a study, Ramachandran and his wife Diane Rogers-Ramachandran used a "mirror box" that could create the visual illusion of two hands for people who actually had only one.
They placed an amputee's arms either side of a mirror, the missing limb on the non-reflective side. With such a placement, the amputees could see the reflection of their normal hand superimposed on the location of their missing hand.
Two amputees watched their normal hand being prodded, and both felt the remarkable sensation of "being prodded" in their missing hand.
In another experiment, when the amputees watched a volunteer's hand being stroked, they too began to experience a stroking sensation arising from their missing limb.
Ramachandran said that the amputees "felt" the actions of others because their missing limb did not provide any feedback to partially inhibit their mirror neurons, no longer telling them that they were not "literally" being touched.
One of the study subjects even said that watching a volunteer rubbing her hand helped the cramping sensation within the phantom limb to cease for 10 to 15 minutes.
"If you do it often enough perhaps this pain will go away for good. If an amputee experiences pain in their missing limb, they could watch a friend or partner rub their hand to get rid of it," Ramachandran said.
The researcher said that massaging the skin helps relieve a painful sensation by restoring blood flow and activating sensory fibres, which inhibit pain messages to the brain. According to him, the amputees in the study might be tapping into the latter mechanism by watching other persons rubbing their hands.
"If performed early enough, this type of therapy may also be used to help stroke patients regain movements by watching others perform their lost actions," Ramachandran said.
A report describing Ramachandran's study has been published in the journal Medical Hypotheses.