Woman with bionic arm regains sense of touch

02 February 2007 NewScientist.com news service

A prosthetic arm that moves and feels like the real thing is now a step closer thanks to a new surgical technique which allows the owner to intuitively control her limb and regain her sense of touch.

Surgeons working on a female amputee in Chicago, US, have re-routed the ends of the motor nerves – which once controlled her arm’s movement – into the muscles in her chest and side. And the ends of the sensory nerves, which fed signals responding to heat and touch from her now-amputated arm to her brain, have been transferred to the skin on her chest.

Claudia Mitchell, a 26-year-old former US marine, is already able to control her prosthetic arm with more skill than is possible with conventional devices. She can carry out simple tasks intuitively, such as cutting up food, and at four times the speed of someone with a conventional prosthesis. And she has regained the sensation of having her arm touched when someone touches the patch of skin on her chest.

Most of the advanced prosthetic arms on the market are powered by myoelectric motors that respond to contraction of muscles in the chest and back. But these are limited, because they allow only one movement at a time, such as bending the elbow or opening the hand, and amputees must learn to contract their chest and back muscles to cause these movements.

Watch a video of the arm in action during a range of tasks, and another showing the prosthetic's startling advantage over a conventional device .....Lees meer: New Scientist

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