A View from Susan Young Rojahn
FDA Approval for Robotic Arm Controlled by Muscle Activity
An electromechanical limb developed by Segway maker DEKA now needs a manufacturer to mass-produce it.
A robotic arm controlled by electrical signals from muscles may soon be available to adults who have lost an arm.
Last week, the Food and Drug Administration announced that it will allow the sale of a prosthetic robotic arm to adults with amputations at the shoulder joint, mid-upper arm, or mid-lower arm. The system, developed by DEKA Research and Development, is controlled by muscles near the attachment site or muscles in the user’s feet.
New Hampshire-based DEKA was founded by Dean Kamen, inventor of many medical devices and the Segway transporter (see “Technology for the Globe”). Bloomberg News reports that the Defense Advanced Research Projects Agency, or DARPA, gave DEKA $40 million to develop the robotic arm and that DEKA will need a commercial partner to mass-manufacture it.
In comparison to commercially available prosthetics, the new arm offers powered shoulder movements and a wider range of wrist movements, researchers reported last year. If produced for sale, the DEKA system would give military personnel and others who have lost all or part of an arm increased capabilities for daily tasks. Justin Sanchez, a program manager in the agency’s new Biological Technologies Office, told Bloomberg that “[before] DARPA made an investment in this area the best we could give back to them was metal hooks.”
Here’s the arm in action:
The approval follows a study initiated in 2009 by the Veterans Administration that involved 36 subjects, mostly veterans, who had lost one or both arms. That study found that 90 percent of participants were able to perform daily activities that they were not able to perform with other prostheses, according to the FDA. The activities included using keys and locks and preparing and eating food.
The DEKA work was backed by DARPA, which has funded several prosthetic-limb projects through its Revolutionizing Prosthetics program. That program has also funded work on robotic limbs controlled by implanted brain-computer interfaces (see “Patient Shows New Dexterity with a Mind-Controlled Robot Arm” and “Brain Chip Helps Quadriplegics Move Robotic Arms with Their Thoughts”).
While the DEKA robotic arm provides some feedback about grip strength by vibrating the user’s skin, better technology for relaying sensory feedback could be available someday. In Ohio, an experimental prosthetic hand with nerve-interfacing implants has given a man who suffered an amputation the ability to sense small objects through the artificial fingertips and even detect how hard he is squeezing them (see “An Artificial Hand with Real Feeling”). A different kind of implant is giving another study participant the ability to detect varying degrees of pressure in a Swiss experiment (see “A Robotic Hand, This Time with Feeling”).