THE IRONIC TRUTH: The bionic hand: Advancement in hand prosthetics

Our hands are the part that we call on to perform almost if not all daily activities and losing even one of them is more than just losing a physical piece of our body, we also lose something that defines us. Our heavy reliance to our hands is the primary reason for amputation cases with incidents that reaches tens of thousands each year in the United States alone. Prosthetics have allowed some functions to those with amputated hands and has advanced to the point wherein the prosthetic hand can rigidly move with muscle twitches.

The latest advancement of prosthetic hand with touch-sensitive fingers has allowed Dennis Aabo Sorensen, a 36 year old Danish man whose hand was surgically amputated due to an accident with fireworks last 2004, to feel objects in his grasp for the first time in 9 years. It is the first prosthetic hand that allows the sense of touch to the wearer in real-time by sending sensory information to the brain via electrodes implanted beneath the skin. After 30 days, the scientists are obligated to remove the hand due to regulations however, it was mentioned that the next implant will be ready within two years and that they aim to put the electrodes in the arm for the long term and for everything to be completely portable.

Sorensen with the bionic hand

According to Sorensen, even though the hand was not exactly 100 % natural like a normal hand, it is a huge step towards further advancement. “The sensory feedback was incredible. 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.”

The mechanisms behind the hand works by sending information about the strength and shape of the grip around an object to a computer chip that re-packages the data into a format that is readily understood by the body’s peripheral nervous system.

Sensory signals are transmitted to the peripheral nervous system using four small, ultrathin electrodes implanted into the ulnar and median nerves of the left arm which then communicated a rudimentary sense of touch to the spinal cord and brain. The hand movement is controlled by the contracting muscles in the lower arm. According to Alastair Ritchie, a lecturer in bioengineering at the University of Nottingham, the “technology would enable the user to know how firmly they are gripping an object, which is vital for handling fragile objects – imagine picking up an egg without any feeling in your fingers?”

It would take some time to polish the technology and even more time to make it available to the masses, but this advancement alone is a huge step in prosthetic technology and will give amputees and even people with physical disabilities the opportunity to live with their full physical capacity.