Doctors have fitted a US marine with a bionic arm that can be controlled by thought alone, giving a sigh of relief to a number of soldiers who have lost their limbs in wars.
The research team is led by Professor Todd Kuiken from the Rehabilitation Institute of Chicago. Last year the research team fitted former US marine Claudia Mitchell with the bionic limb after she lost her arm in a motorcycle accident.
The new limb allowed her to regain the sensation of having her lost hand touched, and provided her the ability to carry out simple chores such as cutting food, eating a banana and doing the washing up. It allowed her to perform tasks four times quicker than with a conventional prosthetic arm.
The scientists believe that as their methods become more sophisticated, amputees will be able to carry out even more tasks. "We're excited to move forward in doing this surgery with our soldiers someday. We've been able to demonstrate remarkable control of artificial limbs," The Telegraph quoted Prof Kuiken, as saying.
He added that the method "provides a lot of hope". The technique is called Targeted Muscle Reinnervation (TMR). It involves re-routing nerves that once controlled the patient's arm to a patch on the chest, where they grow into muscles.
Electrodes on the surface of the chest skin pick up brain signals from the nerves and send signals to operate the artificial arm. When a patient such as Miss Mitchell thinks about moving her hand or arm, the nerves react as if they were still leading all the way down her arm and into the elbow and fingers. If someone touches the patch of skin on her chest, it feels as if they are touching her hand.
Scientists are now working on sensors for the artificial hand that would communicate with the re-routed nerves to provide a patient with the same sensations they would have felt before amputation.
"The idea is that when you lose your arm, you lose the motors, the muscles and the structural elements of the bones, said Prof Kuiken. He added: "But the control information can still be there in the residual nerves."
"All the information is still contained in the residual nerves, because the brain continues to send movement signals to the amputated limb," said Ping Zhou, a biomedical engineer who works with Prof Kuiken.
Bernard Hudgins, the director of Biomedical Engineering at the University of New Brunswick in Canada claims it to be the new approach in treatment of amputated limbs. "Even given current limitations, TMR has proven its worth as a new approach in treating individuals with high-level amputations," he said.
The successful use of the technology is reported in the journal Proceedings of the National Academy of Sciences.