Brain-controlled prosthetics could be widely available in three years time. Iceland-based orthopaedics company Ossur made the announcement after publicly demonstrating the working technology, currently being trialled by two volunteers.
However, given WIRED’s May issue featured the story of a tetraplegic woman who could control a robotic arm using only her thoughts — thanks to a series of electrodes linked to her brain — you’d be forgiven for thinking brain-controlled prostheses were already par for the course.
And yes the tech, known as myoelectric prostheses, has been in development for years. They work by implanting tiny sensors into the muscle adjacent to the site of amputation, using salvaged nerves to send signals from the brain, via the sensor, to the prosthetic, where a receiver translates that message into movement. Ordinary electronic prostheses, including Ossur’s original Proprio Foot, use algorithms to process data from sensors to predict a wearer’s next movement. The company, which made Oscar Pistorius’ Flex-Foot Cheetah blades, only delivered the upgraded version to two patients 14 months ago.
Similar work is being done all over the globe, with different approaches. The Rehabilitation Institute of Chicago has been trialling a technique called targeted reinnervation, which involves the transfer of amputated nerves to remaining muscle and skin. In Sweden, Max Ortiz Catalan has been researching techniques for bone-mounted myoelectric prostheses. Real world trials, where amputees have the prosthetic fitted on a semi-permanent bases, are still rare, however. And Ossur’s latest reveal of its two-person trial shows how much closer we are to these technologies becoming widespread.
The company also claims the prosthetics are the first to translate “subconscious” thoughts into action, rather than intentional, focussed desires to move the limb.
According to an article in Popular Science, the trial began with a short 15-minute procedure under local anaesthetic to implant the sensors. The sensors are powered by magnetic coils embedded in the prosthetic’s socket, and as such are described in the article by Ossur orthopedic surgeon Thorvaldur Ingvarsson as “lifelong sensor[s]”. The prosthetic doesn’t rely on the surgeon attaching the sensor to specific nerves, and it is built to redistribute a wearer’s weight depending on which sensor is activated, the front or back one.
According to the announcement, both patients have adapted to the prosthetic with ease.
“As soon as I put my foot on, it took me about ten minutes to get control of it,” Reuters reports one patient, Gummi Olafsson, as saying. “I could stand up and just walk away. Come back, sit down, use my muscles to move my foot in the position I wanted to use it… It was really strange. I couldn’t explain it. It was like, I was moving it with my muscles, there was nobody else doing it, the foot was not doing it, I was doing it, so it was really strange and overwhelming.”
Although no costs have been announced, Ossur has made a point of saying it plans on launching a largescale clinical trial, and has devised the technology in such a way it will work with its entire line of prosthetic feet, knees and legs.
“The next step might be to get sensing from the environment so you have a feedback loop,” Reuters reports Ingvarsson as saying. Either way, the company estimates the tech will be on the market within three to five years.
Published: 20 May 15 By Liat Clark
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