BarcelonaKnowing whether a person has lost a leg above or below the knee in an accident will be crucial to their quality of life. The difference between retaining the joint or not will determine how a person who has had an amputation will be able to regain walking with a prosthetic. With the options available today, despite their increasing sophistication, the success of prosthetics remains limited. Now, researchers at the Massachusetts Institute of Technology (MIT) in Boston led by American engineer and biophysicist Hugh Hare – a climber whose legs were amputated below the knee as a young man during a blizzard – have gone further and created a unique bionic leg: Through a neural prosthetic interface, which connects the robot directly to the nervous system, it is able to restore the ability to perceive movement and thus the affected path faster and more naturally.
magazine Natural medicine The results of the study, which involved 14 people with below-the-knee amputations, seven of whom had a neural prosthetic interface, were published Monday. People wearing the bionic leg walked 41 percent faster than those who did not, and their walking performance improved in everyday situations such as climbing up and down slopes, stairs, and dead-ends. The authors suggest that their findings could facilitate future reconstruction techniques aimed at restoring neural control of human movement in amputees or paralyzed limbs. “This is the first prosthetic study in history to achieve such a high level of brain control: the human nervous system, not the robot, controls movement,” says Herr.
The head of the Experimental Neurophysiology Group at the Research Unit of the National Hospital for Hemiplegia, Juan de los Reyes, explained to Scientific Media Center Spain In order to move properly, a person must know where to start and have sensory information about the changes that occur during the execution of the movement. This information comes from the same limb that we intend to move, which informs the spinal cord and the brain about the state of all the muscles that control the leg and foot. People without legs who use a classic or hybrid prosthesis do not receive this information: they can perform the walking movement, but they lose the ability to control the movement during execution, as they do not receive any information about how to move the prosthesis.
To solve this problem, the prosthesis they developed at MIT makes it possible to obtain information about the execution of the movement and activate the nerves that transmit it to the spinal cord and, consequently, to the brain. Thus, the central nervous system has a greater ability to organize the movement you want to perform with the prosthesis, and according to De Los Reyes, the execution of the movements is very similar to that of people with both limbs. The end result is an “active prosthesis” because it provides information to the central nervous system to achieve better organization of the movement.
More massive, heavy and complex
However, the researcher warns that the mechanism to be implemented is more bulky, heavy and complex than that used in classic prosthetics. He believes that the “very flashy” appearance of an active prosthesis could be rejected by some people, as the machines used are usually easier to wear and more integrated with the person’s anatomy. For example, they allow you to wear clothes naturally. While the result is an improvement in the functions lost by people with lower limb amputations, one of the expected improvements in the design of active prostheses in the future will require smaller technology that helps reduce the weight and bulk of the entire mechanism required
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