A revolutionary bionic hand with a sense of touch has been tested on a patient for the first time, raising the prospect of artificial "feeling" limbs.
Dennis Sorensen, from Denmark, was able to feel the shape and texture of objects using the robot left hand connected by ultra-fine electrodes to nerves in his upper left arm.
"The sensory feedback was incredible," said the 36-year-old, who spent a month trying out the hand. "I could feel things that I hadn't been able to feel in over nine years.
"When I held an object, I could feel if it was soft or hard, round or square."
Sorensen, who lost his left hand in a fireworks accident, was taking part in a trial in Rome conducted by the Swiss and Italian scientists who developed the experimental prosthetic hand.
The artificial hand detects information about touch using electrical signals from artificial tendons controlling finger movement.
Fine wires send the digitally refined impulses to four electrodes implanted in the sensory ulnar and median nerves of the upper arm.
"This is the first time in neuroprosthetics that sensory feedback has been restored and used by an amputee in real-time to control an artificial limb," said Dr Silvestro Micera, from the Federal Polytechnique School of Lausanne in Switzerland, who leads the Lifehand 2 project.
Sorensen had the hand fitted on January 26 2013 at Gemelli Hospital in Rome. Due to clinical trial safety rules, the sensory electrodes had to be removed from his arm after one month. But the scientists believe they would continue to function without damaging the nervous system for many years.
The results of the study, published in the journal Science Translational Medicine, are the first step towards a true bionic hand which can feel as well as move, say the scientists.
However, they point out that it will be years before such a device becomes commercially available.
Sorensen was injured while handling fireworks during a family holiday. He was rushed to hospital, where his hand had to be amputated.
Since then he has been wearing a conventional prosthesis that detects muscle movement in the stump of his arm, allowing him to open and close his hand and grasp objects.
But without sensory information he cannot feel what he is trying to grasp, making it difficult to gauge the amount of pressure needed.
He now has to cope with the psychological challenge of having re-experienced a sense of touch only to lose it again.
"I was more than happy to volunteer for the clinical trial, not only for myself, but to help other amputees as well," he said.