Person with a prosthetic arm

Amputees able to move robotic arm with their mind

Image credit: Dreamstime

University of Minnesota Twin Cities researchers have developed a technology that allows amputees to move a robotic arm using brain signals instead of their muscles.

Current commercial prosthetic limbs often use a sensor or a cable to pick up on muscle movements in a patient’s existing limb. However, these methods tend to be cumbersome, unintuitive and typically take months of practice for amputees to adapt to.

A team of researchers at the University of Minnesota have created a more accurate, less invasive alternative, based on the premise of allowing an amputee to move their prosthetic with their mind.

The new technology consists of a small, implantable device that attaches to the peripheral nerve in a person’s arm. When combined with an artificial intelligence computer and a robotic arm, the device can read and interpret brain signals, allowing upper limb amputees to control the arm using only their thoughts.

“It’s a lot more intuitive than any commercial system out there,” said Jules Anh Tuan Nguyen, a member of the team behind the device. 

With other commercial prosthetic systems, when amputees want to move a finger, they don’t actually think about moving a finger. They’re trying to activate the muscles in their arm, since that’s what the system reads. This device is different. 

"It knows the patient’s intention," Nguyen adds. "If they want to move a finger, all they have to do is think about moving that finger.”

University of Minnesota Department of Biomedical Engineering Associate Professor Zhi Yang shakes hands with research participant Cameron Slavens,

University of Minnesota Department of Biomedical Engineering Associate Professor Zhi Yang shakes hands with research participant Cameron Slavens.

Image credit: Neuroelectronics Lab, University of Minnesota

The project began in 2012 when Edward Keefer, an industry neuroscientist and CEO of Nerves, Incorporated, approached associate professor Zhi Yang about creating a nerve implant that could benefit amputees. The pair received funding from the US government’s Defense Advanced Research Projects Agency (DARPA) and have since conducted several successful clinical trials with real amputees.

“The fact that we can impact real people and one day improve the lives of human patients is really important,” Nguyen said. “For the past three or four years, I’ve had the privilege of working with several human patients. I can get really emotional when I can help them move their finger or help them do something that they didn’t think was possible before.”

A big part of what makes the system work so well compared to similar technologies is the incorporation of artificial intelligence, which uses machine learning to help interpret the signals from the nerve. This technology allows the team to record human and nerve data accurately, then fill in the gaps and determine what’s going on.

The technology has benefits not only for amputees but for other patients as well who suffer from neurological disorders and chronic pain. Yang sees a future where invasive brain surgeries will no longer be needed and brain signals can be accessed through the peripheral nerve instead.

Right now, the system requires wires that come through the skin to connect to the exterior AI interface and robotic arm. If the chip could connect remotely to any computer, it would give humans the ability to control their personal devices - a car or a phone, for example - with their minds.

“Some of these things are actually happening. A lot of research is moving from what’s in the so-called ‘fantasy’ category into the scientific category,” Yang said. “This technology was designed for amputees, for sure, but if you talk about its true potential this could be applicable to all of us.”

The researchers’ most recent paper is published in the Journal of Neural Engineering, a peer-reviewed scientific journal for the interdisciplinary field of neural engineering.

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