An ultrasonic sensor designed to allow amputees to control each individual finger in their prosthetic hand has helped an amputee—a musician—play the piano for the first time since his injury, note researchers from Georgia Institute of Technology.
Jason Barnes, a musician, lost his hand and most of his forearm 5 years ago due to a work accident. The muscles in his residual limb work with the sensor to control his fingers. The sensor is able to provide fine motor hand gestures that aren’t possible with current commercially available devices, the researchers suggest, in a media release from Georgia Institute of Technology.
“Our prosthetic arm is powered by ultrasound signals,” says project leader Gil Weinberg, professor in the Georgia Tech College of Design, in the release. “By using this new technology, the arm can detect which fingers an amputee wants to move, even if they don’t have fingers.”
Electromyogram (EMG) sensors attached to his muscles control Barnes’ prosthesis.
“EMG sensors aren’t very accurate,” adds Weinberg, director of Georgia Tech’s Center for Music Technology. “They can detect a muscle movement, but the signal is too noisy to infer which finger the person wants to move. We tried to improve the pattern detection from EMG for Jason but couldn’t get finger-by-finger control.”
After attaching an ultrasound probe to the arm, the researchers had a Eureka moment, Weinberg states.
When Barnes tries to move his amputated ring finger, the muscle movements differ from those seen when he tries to move any other digit. Weinberg and the team fed each unique movement into an algorithm that can quickly determine which finger Barnes wants to move. The ultrasound signals and machine learning can detect continuous and simultaneous movements of each finger, as well as how much force he intends to use, the release explains.
“It’s completely mind-blowing,” Barnes shares in the release. “This new arm allows me to do whatever grip I want, on the fly, without changing modes or pressing a button. I never thought we’d be able to do this.”
“If this type of arm can work on music, something as subtle and expressive as playing the piano, this technology can also be used for many other types of fine motor activities such as bathing, grooming and feeding,” Weinberg adds. “I also envision able-bodied persons being able to remotely control robotic arms and hands by simply moving their fingers.”
[Source(s): Georgia Institute of Technology, Newswise]