Seven amputee patients have returned to walking with more natural and faster movements, thanks to the first prosthetic leg completely controlled by the nervous system, without the help of sensors and robotic controllers that move the limb through predefined gait algorithms. The result was published in the specialized journal Nature Medicine by the Massachusetts Institute of Technology (MIT) with the Brigham and Women’s Hospital (here is the complete study, with an explanation of the tests performed).
The novelty lies in the use of a new interface that connects the prosthesis with the nervous system of patients undergoing a particular amputation surgery that preserves the perception of the position of the limb in space.
Specifically, the bionic leg was tested for walking on flat surfaces and on slopes, for walking down a ramp, for walking up and down stairs, and for walking on a flat surface while avoiding obstacles. In all these situations, the prosthesis allowed for 41% faster movements than traditional prostheses, walking at a speed comparable to that of people without amputations. Obstacles along the path were also avoided more easily.
In tests, all movements were more natural. For example, patients pointed their prosthetic toes upward when climbing stairs or stepping over an obstacle, and they coordinated their prosthetic limb better with their intact limb. They were also able to get up from the ground with the same strength as non-amputees.