The first question to ask yourself is of course: Who can be grafted with this type of tool? Nowadays, amputees or those who have simply lost a limb can undergo several operations to make them compatible with prostheses. It is surprising, however, that the brain can send signals to a phantom limb, it remembers the lost arm and can therefore continue to send nervous messages, the same messages that will be detected and processed by the sensors.
Current prostheses propose a transplantation of the nerves of the arm into the chest, but why? Nerve signals are too weak to be captured and analyzed by current technologies, but there is another signal that can be analyzed and transformed into motor information: the myoelectric signal. When the muscle contracts, it sends a signal and that's what will be useful. Thus the idea of re-implanting the nerves of the arm into the pectoral will make it possible to contract or not the muscle to control the arm. Each reimplanted nerve is therefore linked to an electrode that detects contractions and can therefore transcribe it into an electrical signal. But some nerves have another task in a bionic arm. The ulnar nerve, in charge of our ability to pinch, is for example replaced by the median nerve. Recovering a lost limb through this procedure obviously requires significant rehabilitation in order to have fluid movements. However, an arm is not only used to grasp objects, we also have a hand with a very developed sense of touch: how is it possible to account for this sense with a bionic arm? When the surgeon implants the sensitive nerve into the patient's chest, he must connect this nerve to an artificial sensor that collects the necessary information such as heat, hand pressure.
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