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In a groundbreaking development, researchers at the Science Translational Medicine have engineered a prosthetic limb that directly interfaces with the wearer’s nerves. This innovation, as reported by Wired, is a significant leap forward in the realm of prosthetics, marking a departure from traditional models that rely on muscle movement and residual limb motion.
It works by surgically connecting the prosthetic to the nerves that once controlled the missing limb, enabling a more intuitive and natural movement. The procedure involves grafting small muscle pairs into the residual limb. These muscles, which work in opposition, or as ‘agonists’ and ‘antagonists,’ mimic the natural push-pull dynamic of muscles in the body. When the wearer thinks about moving their prosthetic, the nerves in the residual limb activate these muscle pairs, which then send signals to the prosthetic limb, resulting in movement.
This innovative approach allows the prosthetic to provide sensory feedback to the wearer. When the prosthetic limb moves or comes into contact with an object, the muscles in the residual limb contract and stretch, sending signals back to the brain. This creates a sensation of movement and touch, a feature absent in traditional prosthetics.
From the article:
To send all this nerve information to an actual prosthesis, [researcher] Ortiz-Catalan and the team connected the implanted electrodes to a titanium implant drilled into the patient’s humerus bone in the upper arm. The implant facilitated two-way communication between electrodes in the body and the external prosthesis. This was no small feat: Starting from the drilling of the implant, the entire process took over six months, including a 12-hour surgery to reroute all the nerves.
Once all was in place, the scientists could monitor how their implanted electrode system communicated with the prosthesis. First, they tracked the electrical signals from each implanted electrode. While fuzzy at first, the signals became much stronger. According to Jan Zbinden, a PhD student in Ortiz-Catalan’s lab and study coauthor, this meant that the nerve fascicles were successfully integrating into their respective muscles and supplying them with adequate signals.
The development of the prosthetic is a significant stride in the field of prosthetics and holds immense potential for improving the quality of life for amputees. However, it’s important to note that the technology is still in its early stages and further research and testing are required to refine the system and make it widely available.
