Phantom Limbs Can Move in Anatomically Impossible Ways

By Brett Israel | October 28, 2009 10:03 am

amputeePhantom limb syndrome is an eerie condition, in which amputees have the physically painful sensation that their missing limbs are still present. Now, a small new study has shown that people can twist those ghostly limbs in anatomically impossible ways, while still feeling that the limb is real and present. In essence, each amputee’s brain reshaped his understanding of where his body was. The findings show that the brain can alter how we perceive our bodies all by itself, without input from our senses [Reuters].

Researchers had patients with “vivid phantoms” try to move their wrists in a physically impossible waya 360 degree spin of the wrist around the long axis of the forearmand found that 4 of the 7 patients could move their wrists this way. Some patients that were able to move their wrists later reported that their phantom hands were now more difficult to move from side to side because of changes in their phantom arms’ shapes.

To corroborate that the individuals had really learned the new movement (after all, the scientists couldn’t see the phantom limbs) the researchers had them perform a task known as left-right hand judgement before and after their training. The ability to twist the phantom wrist in a new way allowed the participants to react to this task faster than they could before they had learned the impossible move [Science News].

The study, published in the Proceedings of the National Acadmey of Sciences, may lead to treatments that help alleviate the pain associated with phantom limb syndrome by helping patients learn to move their phantom limbs into a more comfortable position. The findings also raise the “speculative, but not outrageous” possibility that patients could cope with movement problems due to stroke, back pain, or pain in other regions of the body, by being trained to change the image of that body part, according to the researchers [Reuters].

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Image: iStockphoto

MORE ABOUT: pain, senses
  • Haruspex

    “4 or the 7 patients” should read “4 of the 7 patients”

    Thanks for the interesting article!

  • Eliza Strickland

    Thanks for the catch, Haruspex! Fixed the typo.

  • Nick

    I can’t remember exactly where I read this, but some study showed that when we are driving, our brains mental map of self extends to include the car. Same goes for tool use, screwdriver becomes part of your mental map of your hand.

    Very recently, researches attached a robot hand with pressure sensitive fingers to a guy’s missing hand. They connected the sensors to his hand nerves, and he is able to not only FEEL (that’s right, he can feel with his robot hand. to heck with jetpacks, this is the kinda future I want.) but control the robotic hand with his brain through those nerves.

    From phantom limb to robotic limb you can feel with. Next stop: hook me up to an ABB industrial robot so I can lift cars with it!

  • Peter the Great

    i think ive read that article too. it was here on discover somewhere i think.


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