Alex Smith was He was 11 years old when he lost his right hand in 2003. A drunk driver rams a boat into his family's boat on Lake Austin, causing the boat to sink. He was hit by a propeller and cut his hand in the water.
A year later, he got a myoelectric armA type of artificial limb operated by electrical signals in the muscles of his residual limb. But Smith rarely used it because it was “very, very slow” and had a limited range of movements. He could open and close his hands, but could not do anything else. He tried other robotic arms over the years, but they had similar problems.
“They're not super functional,” he says. “There's a huge delay between performing a task and then artificially actually doing it. In my day-to-day life, it has become much quicker to figure out other ways to do things.”
Recently, he's been trying a new system by Austin-based startup Phantom Neuro that has the potential to provide more lifelike control prosthesesThe company is building a thin, flexible muscle implant that could allow amputees to make wider, more natural movements by simply thinking about the gestures they want to make.
“A lot of people don't use robotic limbs, and that's mainly because of how terrible the control systems are,” says Connor Glass, CEO and co-founder of Phantom Neuro.
In data shared exclusively with WIRED, 10 participants in a study conducted by Phantom used a wearable version of the company's sensors to control a robotic arm already on the market, allowing 11 hands and wrists An average accuracy of 93.8 percent was achieved in gestures. Smith was one of the participants, while the other nine were able-bodied volunteers, which is common in early studies of prosthetics. The success of this study paves the way for future testing of implantable sensors on the Phantom.
Current myoelectric prosthetics, such as the one Smith has tried, read electrical impulses from surface electrodes that sit on the amputated stump. Most robotic prostheses have two electrodes or recording channels. When a person turns his arm, the muscles in his arm contract. Those muscle contractions also occur in amputations of the upper limb when they bend. Electrodes pick up electrical signals from those contractions, interpret them, and initiate movement in the prosthesis. But surface electrodes don't always capture stable signals because they can slip and move around, reducing their accuracy in real-world environments.