Sally’s right arm is like a set of car keys that she can’t quite find. Or sometimes like a pencil that she is sure she was holding just a second ago. This is how the loss feels several years later. Earlier the pain had been sharper. Sometimes there was the sense of a school bully, bending her arm back to see if she could touch her shoulderblade. Most of the time though, it was a dull ache. She’d reach for cups and they would remain unmoved. Wave an invisible hello. She would feel fingers when it rained. Sometimes when her boyfriend stroked her cheek it was almost like he was trying to hold her hand.

R. N. was born with only three fingers on one hand. She’d learnt to live with this though, only experiencing the general suffering of someone with a deformity going through school.  She was eighteen when the hand had to amputated after a car crash. It was hard to explain, but her new phantom hand had five fingers (although some were shorter than others). Thirty-five years later she sought treatment for the pain in a hand that didn’t exist. They put her in a room with a mirror in a box.

Like all ghosts, phantom limbs are still a mystery unsolved by science. Although anywhere between sixty to eighty percent of amputees experience some kind of phantom sensation, the full reasons for this are unknown. Three of the best guesses for how it occurs are: changes in the brain after amputation (maladaptive plasticity); conflict between signals in the brain (proprioception); and vivid limb memories.

It sounds like lucid dreaming for limbs, but the thing about these phantom sensations is that the suffering is no less real simply because the limb isn’t. We’ve long been able to trick our minds and it’s not surprising that with something as intense as an amputation the brain tries to adapt.

Neuroscientist Vilayanur Ramachandran has spent years treating cases like these. He had a patient suffering from intense cramping where his phantom hand was clenched so tightly his invisible fingernails were digging into his phantom palm. There have been less painful cases: people feeling watches or rings worn on missing arms. But sometimes the feeling is too intense, and because of the nature of it, you can’t exorcise or exercise the pain away.

Which raises the question: how do you amputate a phantom limb?

Mirror box visual feedback is the idea of using reflections of the full limb to help treat the phantom one. By superimposing this reflection where the limb is supposed to be, the brain can be tricked into responding. It was this process that Ramachandran and his colleague Paul McGeoch used with R. N. After thirty minutes a day for two weeks she was able to move her phantom fingers and was relieved of pain. Fascinatingly, while she’d gone from three deformed fingers to five invisible deformed and painful fingers after the amputation, since the treatment she felt that all the fingers on her phantom hand were of normal length. In their study on phantom fingers, McGeoch and Ramachandran stated that this could mean that “the brain has an innate template of a fully formed hand”.

Importantly, when providing pain relief in this manner, clinicians need to distinguish between imagined movements and real movements of phantom limbs. How this distinction is made is unclear, but it becomes all the more relevant when you consider the power of the mind, not just in treating, but also extending the possibilities available to amputees.

An experiment in 2009 by Lorimer Moseley and Peter Brugger aimed to see if phantom limbs could do what normal limbs couldn’t. They tested seven arm-amputees, and successfully trained four of them to be able to contort their phantom limbs in new ways. A fair question would be how this new movement could be proved. The answer involves the patient’s response times to visual stimuli, showing both possible and impossible movements (full explanation here). In being able to generate new motor commands they were able to do things that normal limbs couldn’t, including wrist movements that rotated freely from the forearm. The extension of this is that it could become possible to gain the ability for enhanced prosthetic movement that would be outside the traditional realm of possibility.

But it’s not just people with missing limbs who are haunted. Researchers now say that non-amputees can also be made to feel phantom limbs, and even similar pain. Extending the rubber hand illusion (a fake right arm is stroked with a brush, which can trick people into feeling the dummy hand as their own), neuroscientists from Stockholm simply made brushing movements in mid-air in full view of the participants.

Fascinatingly, while she’d gone from three deformed fingers to five invisible deformed and painful fingers after the amputation, since the treatment she felt that all the fingers on her phantom hand were of normal length.

“We discovered that most participants, within less than a minute, transfer the sensation of touch to the region of empty space where they see the paintbrush move, and experience an invisible hand in that position,” said researcher Arvid Guterstam.

It’s amusing to imagine a room of scientists all tenderly painting invisible hands, but this image becomes more startling when in the next experiment the invisible hands were stabbed by the researchers. In order to prove that the illusion had taken hold, at the place where the hand was perceived to be the researchers made a stabbing motion with a knife and measured the participant’s responses, such as sweating and heart rate. The reaction was the same as if their own real hand had been threatened, which showed that they were able to not only have sensations, but assimilate a body part they couldn’t see as their own.

If we can be made to feel phantoms, and amputees can become double-jointed, it seems that our perceptions of our bodies, believed to be the most stable thing about us, are far more malleable than we thought. We can have out-of-body experiences when watching video camera feeds manipulated around us; we can fear for the safety of fingers that don’t exist; and we can even get to the point of feeling like we are shaking hands with ourselves.

The sense of ownership over the self may prove to be much more fluid than we think. And science is ready to make the most of this flux. The ghosts are ourselves, with limbless potential.

Rafael S.W. is a recent graduate of creative writing and one of the founding members of Dead Poets’ Fight Club. He has been published in Voiceworks, Going Down Swinging and Dot Dot Dash. He also competes in poetry slams and giant-sized chess games.

Photo used under Creative Commons from Soffie Hicks