An interesting bit of news out of the University of Utah is the announcement of a DARPA-supported project to develop a bionic arm, with controls based on the university’s proprietary Utah Electrode Array. The device, pictured on the right, is also known as the Utah Slanted Electrode Array, a miniature gadget that should allow central nervous system’s signals reaching peripheral nerves to be transduced to control the bionic arm. In essence, the device should allow a person to move the artificial arm with thoughts only. (Sceptics questioning the feasibility of such a project are urged to check the flashbacks posted below).
“Imagine an artificial arm that moves naturally in response to your thoughts, that allows you to feel both the outside world and your own movements, and that is as strong and graceful as an intact, biological limb,” says bioengineer Greg Clark, the University of Utah’s principal investigator on the project. “That’s what our researchers, teaming with others around the world, are setting out to achieve… People’s arms and hands are not only tools, but also an important means by which they explore the world and interact with others. We hope to restore that capability.”
The research is part of the Revolutionizing Prosthetics 2009 project sponsored by the Defense Advanced Research Projects Agency. DARPA said in a news release that it wants to “revolutionize prosthetic devices for amputee soldiers. Over the next four years, researchers will create a mechanical arm that has the properties of a biological limb…”
University of Utah researchers will focus on developing and testing a “peripheral nerve interface” – an implanted device that would relay nerve impulses from nerves in the residual limb to a small computer worn on a belt and then to the bionic arm. That would allow a person to move the artificial limb like a real one. Sensors in the artificial arm would send signals to the computer and on to the interface device, which would relay the signals to nerves in the remainder of the amputated arm and then to the brain, allowing the person using it to sense the arm’s motion and location, and to feel objects with the mechanical hand and fingers.
The neural interface device between the arm and the person wearing it would be implanted in what is left of the amputated arm or shoulder, and would send signals wirelessly to the artificial arm via the belt-pack computer. The interface device would use a modified Utah Electrode Array, a pill-sized device containing 100 tiny electrodes that was developed by University of Utah bioengineering Professor Richard Normann.
If the University of Utah interface device ultimately is chosen for the bionic arm, electrode arrays will be implanted in some or all of the four major nerves in the residual limbs of people with upper-arm amputations. Each of the 100 electrodes would selectively “listen” or “talk” to a small number of fibers in a nerve.
Researchers at other institutions, meanwhile, will develop the prosthetic arm itself and will study other kinds of neural interfaces that could operate the bionic arm, including a device implanted to receive signals from the brain instead of nerves in the residual limb.