Amputees 'Feel' Lost Limbs After Nerve Work

Found this post on Discovery News, which can be accessed here.

It's a great article on, well, exactly what the title says. It's not phantom limb syndrome, it's progress.




Nov. 27, 2007 -- Amputees given prosthetic limbs could soon "feel" with their new hands or feet, after a team of scientists successfully rerouted two patients' key nerves.

Scientists at the Rehabilitation Institute of Chicago and Northwestern University announced late Monday they had rerouted through their chests the nerves of two patients that had transferred sensation from the hand to the brain.

After several months during which the nerves re-established themselves in the chest muscles, physical pressure, heat and cold, and electrical stimulus were applied to the areas of the nerves and the patients said they could feel the effect.

In some of the testing, the patients could even specify which area on the hand they could feel; one, a woman identified as STH, at one point pinpointed a strong feeling of the skin stretching and the joint position of her ring finger being extended.

Moreover, the patients consistently distinguished between the sensation of the chest nerves and those of the missing limbs.

The scientists suggest their success in reviving such specific sensation identified with missing limbs could lead to establishing nervous system feedback in prosthetic devices like artificial hands, arms, feet and legs.

"Our results illustrate a method for creating a portal to the sensory pathways of a lost limb," they said in the online edition of the Proceedings of the National Academy of Sciences.

"This work offers the possibility that an amputee may one day be able to feel with an artificial limb as though it was his own."

Led by Todd Kuiken, director of the Neural Engineering Center for Artificial Limbs at Northwestern University, and director of Amputee Services at the Rehabilitation Institute, the researchers tested two volunteer patients: BSD, a 54-year old man who lost his arms at the shoulder due to electrical burns, and STH, a 24-year old woman who underwent a left upper arm amputation after a car accident.

In both they took the remaining four main nerves that had connected to the hands and transferred them to different areas of the chest, attaching them into the chest muscles.

In BSD, this took place nine months after the injury. Five months later, the report said, when touched on the chest he began registering sensations from the phantom limb.

Depending on the location and the strength of the pressure put on the chest, BSD registered feelings on the palm or backside of the missing hand.

In STH, the transfer of the nerves was made 15 months after her accident. Four months later, she was registering feelings from the lost hand and wrist from the nerves moved to her chest.

The scientists say their results did not show a full recovery of sensation in all four of the nerves, noting there may be limits to a patient's spatial perceptions and ability to handle complex sensations.