volunteer photo

Matthew Beckstead, amputee, volunteer.

According to Department of Biomedical Engineering professor, Gregory Clark, PhD, “This would allow a user to use the advanced prosthetic hand just by thinking about it because we would wiretap into the remaining arm nerves, capture the signals and send them to the artificial hand. It would also allow the user to receive sensory feedback from the real prosthetic hand as if it’s a real biological hand; that is a sense of touch and a sense of movement.” Clark is leading an interdisciplinary research team involving clinicians, neuroengineers, material scientists, electrical and computer engineers, rehabilitation specialists and patient volunteers.

See below for a brief video showing an amputee controlling a virtual arm with his thoughts.

Researchers, led by Clark, are further developing the Utah Slanted Electrode Array, a neural interface that uses 100 electrodes which connect with nerves in an amputee’s arm to read signals from the brain – telling the hand how to move. The Utah Slanted Electrode Array was first developed by Department of Biomedical Engineering professor emeritus Richard Normann and will ultimately communicate with the prosthetic limb wirelessly.

Clark photo

“People wouldn’t have to do anything differently from what they’d already learned how to do their whole life with their real hand. They’ll just think what they normally think, and the prosthetic hand will move.” said Professor Clark. Current prosthetic limbs can make only limited movements via remaining muscles, such as with a shoulder shrug. Clark hopes that the Utah Slanted Electrode Array will give users of this advanced prosthetic hand over 20 types of hand and wrist movements by using electrical signals from remaining nerves and muscles. The sensory feedback afforded by the array might help the user not only to feel, but also to feel whole again, Clark said. Most conventional prosthetic limbs also provide no sense of touch or movement.

The funding from the Defense Advanced Research Projects Agency (DARPA) will cover about 18 months of research and pay for testing on two human volunteers. The Utah team is eligible to receive up to $4.4 million from DARPA over the next five years. “We have the opportunity to not only significantly improve an amputee’s ability to control a prosthetic limb, but to make a profound, positive psychological impact,” DARPA program manager, Doug Weber, said in a news release. “Amputees view existing prostheses as if they were tools, like a wrench, used only to perform a specific job, so many people abandon their prostheses unless absolutely needed. We believe [the new prosthetic limb] will create a sensory experience so rich and vibrant that the user will want to wear his or her prosthesis full time and accept it as a natural extension of the body.”

The funding is part of DARPA’s Hand Proprioception and Touch Interfaces (HAPTIX) program, which aims to create an artificial limb that is so realistic, it can provide a psychological benefit to the wearer. President Barack Obama cited the project in his State of the Union Address in January as an example of the kind of technological innovation that can unleash new jobs while also benefiting people.

The new tests on human subjects will build upon shorter DARPA-funded tests recently conducted on four human subjects at the U. These tests successfully demonstrated people’s ability to control and receive sensation from a virtual prosthetic hand displayed on a computer monitor, as shown in the video above.

The funding will be shared with U startup, Blackrock Microsystems, and University of Chicago assistant professor Sliman Bensmaia and his team, who are developing the interface’s sensory algorithms.  The U will not develop the prosthetic hand or the wireless electronics. The wireless technology will be developed by local company and U collaborator, Ripple, LLC, in Salt Lake City, and the electrodes for the array are being manufactured by Blackrock Microsystems in the U’s Research Park.

So far, the arrays have provided the user with up to 10-12 different types of movements of the virtual fingers and wrist plus over 130 different locations and types of touch and sensory feedback. The use of interfaces in peripheral nerves to control prosthetic hands was pioneered in earlier studies by U investigators, including present team member Douglas Hutchinson who specializes in hand and microvascular surgery and is hand fellowship d irector at the U and holds adjunct appointments in the Departments of Biomedical Engineering and Physical Therapy.

Other U faculty team leaders include research associate professor Loren Rieth and professor V. John Mathews, both from the electrical and computer engineering department; bioengineering research assistant professor David J. Warren; Christopher C. Duncan of physical medicine and rehabilitation; and bioengineering professor Normann.

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