A man whose left arm was amputated nine years ago has found a sense of touch thanks to an experimental artificial hand, his nerves where attached to the amputated limb, informs AFP.
According to scientists, this biomedical marvel paves the way for achieving the next gen of prostheses for patients to feel – in real-time – with a sensory-enhanced prosthetic hand.
Swiss, German and Italian researchers have tested this bionic hand at the Gemelli Hospital in Rome, Italy, on a 36 year old Danish, whom doctors had amputated his left arm, nine years ago after he was injured in an explosion while handling fireworks outside his home.
The results of this clinical study were published Wednesday in the journal Science Translational Medicine Scientific American.
“I could feel things that I hadn’t been able to feel in over nine years“, said the patient, Dennis Aabo Sørensen, adding that the sensory response of the prosthesis is “truly incredible”.
During the tests, the patient was blindfolded and had earplugs. The patient depended on the sense of touch, said researchers.
Doctors, coordinated by Silvestro Micera form l’Ecole Polytechnique Fédérale in Lausanne (EPF) in Switzerland, have developed the bionic hand with which the patient can adjust its force to grasp objects and identify their shape and texture.
Micera and his team enhanced the artificial hand with sensors that detect information about touch. This was done by measuring the tension in artificial tendons that control finger movement and turning this measurement into an electrical current
This prostheses is equipped with sensors able to react to artificial tendons tension, transforming information into electrical impulses emitted when patient is handling an object. These signals, converted into the equivalent of nerve impulses are transmitted to the four electrodes in the peripheral nerve graft of the arm.
“This is the first time we can restore sensory perception in real time with a prosthesis”, said Silvestro Micera.
The next step involves miniaturizing the sensory feedback electronics for a portable prosthetic. In addition, the scientists will fine-tune the sensory technology for better touch resolution and increased awareness about the angular movement of fingers.
Surgery was performed by a team of surgeons and neurologists in January 2013 at the Gemelli hospital in Rome, under the guidance of doctor Paolo Maria Rossini who implanted electrodes in the patient’s amputated left arm.
About three weeks of testing was required before the prosthesis was connected to the electrodes.
Afterward, researchers and patient tested the artificial hand for a week. The electrodes were withdrawn after a month, according to European legislation governing clinical trials.
But according to researchers, they could be in place and operating for several years without damaging the peripheral nerves.
However, it will take several years before the bionic hand is marketed, explained Stanisa Raspopov at EPFL, one of the coordinators of the study, conducted within the European project LifeHand2.
“Everything will depend on the following clinical trials”, he said, without specifying, however, the number of patients who take part in them. In his opinion, the marketing will be “over five years at the earliest, or more than 15 years at the latest”.
From this point of view, it is at a difficult this stage to estimate the price of such a bionic hand, but their mass production should bring prices down.
The next step will consist in two phases: the miniaturization of electronic compounds to integrate in the prosthesis and the development of efficient batteries, said Stanisa Raspopov.
Scientists will, however, improve sensory device to obtain a better resolution of the sense of touch, for the patient to feel the movements of the fingers with a high degree of precision.
Source: EPFL / Photo: © LifeHand 2