University of Utah researchers are among collaborators at numerous universities, hospitals and companies who will work together to develop an artificial arm that looks, feels and works like a natural arm — controlled by thought and able to move naturally, clear to the fingertips, while sensing its environment.
The Department of Defense, which is funding the project for up to $55 million, wants a device with the properties of a natural arm, ready for clinical testing in 3 1/2 years. The impetus is replacing amputated arms of soldiers wounded in battle.
The U.'s contribution centers on communication between an artificial limb and what's left of the original arm. They're developing a peripheral nerve interface, a key task that could bring up to $10.3 million of the grant to the U. and its own subcontractors.
They're not starting from scratch.
"If we didn't have a head start on these issues, we wouldn't be able to have a dream of this," says Greg Clark, principal investigator for the U.'s piece of the project and a bioengineering associate professor.
"The teams tasked with different parts of the project were all selected in part for their previous advances in various areas that can be exploited to build the dream prosthetic arm. Current prosthetics have not yet managed articulated fingers."
The U. team is modifying an existing interface device, the Utah Electrode Array, a pill-size device developed and refined over the past 15 years by its inventor, Richard Normann, bioengineering professor, and colleagues. University researchers will use a "slant" electrode array that has tiny electrodes of varying lengths, since they must reach nerve fibers at different depths in the user's residual arm, says Clark.
Only because so much relevant work, like creation of the electrode array, has been done is the ambitious project feasible with its tight timetable, Clark says.
The electrode array goes directly into the nerves in the residual limb, where each electrode either talks or listens to specific nerve fibers. The human body determines the language any prosthetic will have to use.
"I can wire tap and extract information from the nervous system, but I can't change it," says Clark.
For the arm to work on neural signals, it will have to be built based on, and responding to, those signals.
More than $30 million of the funding will be used for phase one, says the project sponsor, the Defense Advanced Research Projects Agency.
The U. has picked its own subcontractors for the first phase. Ripple, a Utah company founded by Shane Guillory, will develop a wearable computer that can understand and translate the signals being sent from the nerves to the array to the artificial arm and back again. Germany-based Fraunhofer IZM will figure out how to make the electrode array wireless and combine it with signal processors and amplifiers to relay the signals back and forth. And Fraunhofer IBMT will design a process to encapsulate components so they can safely be implanted in people.
The prosthetic arm itself, other neural interfaces, even the motor that powers the arm, are being developed at other institutions. Johns Hopkins University's Applied Physics Laboratory oversees the grant and the entire project.
Utah's initial grant is $4.8 million, rising to as much as $10.3 million depending on a successful first phase.
Other U. researchers involved include Normann; Dr. Douglas T. Hutchinson, an associate professor of orthopedics; and Nicholas Brown, a research assistant professor in orthopedic surgery, who will help with preclinical and human studies; bioengineering professor Patrick Tresco, who will test the device and its components to ensure safe use in humans; Reid Harrison, assistant professor of electrical and computer engineering, who will develop miniature components such as amplifiers and signal processors; and Florian Solzbacher, an assistant professor of electrical and computer engineering, who will manufacture the array's components, assemble them and enclose the device to survive being implanted.