Over the past months, we have witnessed extraordinary advances in prosthetics, but simulating something close to tactile perception is a much more complicated challenge. Of course, that doesn't stop experts from facing that challenge and creating interfaces that largely restore the ability that was lost with the original limb. One of the most striking examples comes from the University of Linz, where a new prosthetic leg was created that can transmit to the user the contact with the ground at every step.
A first for prosthetics
Wolfgang Rangger is 54 years old. His life took a drastic turn eight years ago when he suffered a stroke that caused a blood clot and the loss of his right leg. Fortunately, not only did Rangger recover, but he has become the user of the first prosthetic leg with tactile perception. In general, the idea is that the brain controls a prosthetic, which represents sending information from the brain to the artificial limb. However, Rangger's prosthetic works in the opposite direction, so the prosthetic basically becomes a "foot simulator" that the brain can interpret. This not only optimizes the rehabilitation process for the patient, but also has the potential to fight the so-called "Phantom Limb Syndrome" that many amputees suffer from.
How the tactile prosthetic works
The development of this prosthetic leg is the responsibility of Professor Hubert Egger at the University of Linz. The first step required surgery on Rangger's leg, in which doctors managed to redirect the nerve endings of the foot in the stump to healthy tissue in the thigh, placing them near the surface of the skin. The other half of the equation consists of six special sensors installed in the artificial foot of the prosthesis, connected to a series of nerve stimulators that work directly on the stump. Rangger's description leaves no room for error: "It feels like I have my foot again." Rangger added that he feels concrete, sand, gravel, grass, and even small stones when walking.
Relief from phantom pain
As if that were not enough, Rangger stopped feeling pain a few days after surgery and using the new prosthetic. Rangger's quality of life was critical due to the amputation, suffering from pain for years and needing powerful drugs like morphine. Professor Egger explains that phantom pain is nothing more than the brain increasing its sensitivity while searching for information about the lost limb. The new prosthetic serves as a kind of "I'm here!" that can help the amputee considerably. For now, the cost of the prosthetic is quite high (between 10,000 and 30,000 euros), but it is only a matter of time before the price comes down.
