A team of Italian and Swiss researchers have developed the LifeHand 2, the first artificial hand that restores a sense of touch to patients with a missing limb. The limb is wired up to electrodes implanted into the nerves at the point of amputation to allow easy control with no more than a thought. While still in the experimental stages, this new type of prosthetic could allow amputees to more easily lift and manipulate objects without having to carefully watch their every move.
The researchers installed the new prosthetic onto the arm of 36-year-old Dennis Aabo Sørensen, a Danish man who lost his hand nine years ago in a fireworks accident. To reactivate Sørensen’s sense of touch, the hand was equipped with sensors in each finger that would detect information about objects that were being touched. Measurements of the tension in the artificial tendons of the hand were then translated into electrical signals, which would be converted by an algorithm into impulses that could be transmitted through the body’s nervous system.
For Sørensen, the results were life-changing — even when blindfolded and wearing earplugs, he was able to distinguish between a mandarin orange and a baseball, bottles of various sizes, and between wood and fabric. In an interview with NPR, he said, “It was really, really amazing because suddenly my artificial hand and my brain were working together for the first time in many years. It was very close to be like your normal hand.”
Due to Europe’s laws on clinical trials, the prosthetic and electrodes had to be removed after a month, but scientists are confident that similar devices could be remain functional for years without damaging the wearer’s nervous system.
While scientists still don’t know when similar prosthetics will become commercially available, this study is an important proof-of-concept. Right now, the equipment involved in translating the hand’s signals to something the nervous system can understand is large and cumbersome — taking up an entire table in the lab. Now, researchers need to work on making a portable version of the device that could be tested by volunteers in everyday situations. The complete findings were reported in the journal Science Translational Medicine.