Despite recent advances in technology for upper-limb prostheses, artificial arms and hands are still unable to provide users with sensory feedback, such as feeling when touching things or enable the user to be aware of limb position and movement.
Without this feedback, even the most advanced prosthetic limbs remain numb to users, a factor that impairs the limbs effectiveness and their wearers’ willingness to use them. In a step toward overcoming these challenges, the Defense Advanced Research Projects Agency (DARPA) www.darpa.mil has awarded prime contracts for Phase 1 of their “Hand Proprioception and Touch Interfaces or (HAPTIX) program.
The HAPTIX program seeks to create a prosthetic hand system that moves and provides sensation like a natural hand. Also, by restoring sensory functions, HAPTIX aims to reduce or eliminate phantom limb pain, which affects about 80 percent of amputees.
HAPTIX teams intend to leverage commercially available technologies such as intramuscular electrodes and lead technologies developed initially for cardiac pacemakers but now used in several modern implantable medical devices.
NIH www.nih.gov is providing support to Ripple LLC www.rppl.com, University of Utah www.utah.edu, and Case Western Reserve University www.case.edu on research to be funded and administered by DARPA.
Daniel McDonnall PhD and his colleagues at Ripple LLC have developed a wireless device to implant directly into muscles that may help improve the reliability of prosthetic limbs. The implant should allow users to freely move multiple joints in the prosthetic limb.
The implant collects information from the muscles and sends that information wirelessly to an external receiver built into the prosthetic and also creates a more natural feeling of prosthesis control.
Richard A. Normann, PhD, and colleagues at the University of Utah have developed a tiny device that can be implanted in peripheral nerves to communicate with nerve fibers and control muscle movement.
Studies of the device suggest that the implant does not cause side effects and may be effective for long-term use. The data also suggests that the device is capable of creating natural movements while minimizing muscle fatigue
Dustin Tyler, PhD, and his team at Case Western Reserve University have developed, implanted, and tested high density electrode nerve cuffs in patients with spinal cord injuries in an effort to return some mobility.
The cuffs wrap around major nerves in the arms or legs and stimulate them electrically resulting in muscle contractions and simple movements. These cuffs are going to be tested to stimulate nerves in the residual limb directly above a prosthetic arm to see if the user can control the prosthesis more naturally and experience sensation.
To help the teams quickly and cost effectively conduct research, DARPA is providing prosthetics simulation software to use to test designs. The software includes a variant of the DARPA Robotics Challenge Simulator from the June 2013 Virtual Robotics Challenge.
DARPA is also working with teams at Cleveland Clinic http://my.clevlandclinic.org, Draper Laboratory www.draper.com, Nerves Incorporated www.nervesincorporated.com, University of Pittsburgh www.pitt.edu, and the University of Florida www.ufl.edu.