The world's first brain-controlled leg prosthesis is being tested at the Rehabilitation Institute of Chicago (USA).
Such prostheses, called bionic, have already been developed to replace the upper limbs, but it turned out to be more difficult to make an artificial leg - the motors that drive it have to cope with a large load so that a person can get up and go, but at the same time the device must be light and compact.
The developers pay considerable attention to the safety issue: errors in the software that controls the movement of the prosthesis based on brain signals can lead to a fall of a person, which in turn is fraught with dangerous consequences.
Zach Sauter, who lost his leg in a motorcycle accident, helps researchers test a prosthesis. He admits that a bionic prosthesis is fundamentally different from a mechanical one he has to wear. For example, when climbing stairs with a bionic prosthesis, Sauter can alternate between his right and left steps, rather than pulling up the prosthesis after his good leg, as he did before. Walking on inclines has also become more natural.
Some of the modern leg prostheses are purely mechanical, like the one Sauter uses in everyday life. Others (robotic) are equipped with motors, a processor, and sensors that monitor the knee position and the forces acting on the prosthesis.
They allow people to walk, but they are rather awkward to climb or descend stairs with. Another disadvantage of robotic prostheses is that they do not allow you to move the artificial leg without using the hands when a person is sitting.
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A bionic limb controlled by brain signals is a much more advanced device. In addition to sensors for mechanical stress, it is equipped with electrodes that are in contact with the skin of the stump and receive nerve impulses that control muscle contraction. The software interprets these signals together with information from the sensors and calculates what Sauter is trying to do.
The creators of the prosthesis are working to reduce the number of software flaws, and also try to make the device lighter and quieter. Perhaps commercial samples will be on the market in the next 3-5 years. The estimated cost of the device is not named (the price of bionic hand prostheses varies from $ 20,000 to $ 120,000).