"Igor Spetic, in Cleveland, suffered after his amputation from extreme, persistent pain, which he felt permanently emanating from the hand he no longer had."

"'It was unbearable, twenty-four seven, as though my hand were in a clamp,' he says. Since the last thing he vaguely recalls about his accident is his hand clutched in a vise as he reached out toward the mechanical press that crushed it, it seems that his mind had continued to feel that final moment, like a clanging bell that is the last thing remembered, and still heard on his hospital bed, by the victim of a train accident. His hand is so much there from the brain’s point of view that the brain may be creating the pain it thinks the hand ought to be feeling, the last tactile sensation it can recall. This kind of phantom pain in amputated limbs is a widely observed phenomenon, but for a long time it was thought to be a response to trauma of the 'cauterized' nerves in the residual limb. One of the things that Dustin Tyler’s project in Cleveland has helped confirm is that it is also a cognitive phenomenon, placed much 'higher up' in the system. After the sensors in Spetic’s arm were stimulated, his pain diminished, and then vanished. Reassured that the hand had moved on, that the trauma had passed and was no longer in need of response, the brain released it from the emergency state of feeling pain."

From "Feel Me/What the new science of touch says about ourselves," by Adam Gopnik.