A little while ago, when most of the world was trudging through its daily routine, a team of engineers and scientists at the Johns Hopkins University Applied Physics Laboratory (APL) taught a mechanical hand to play rock-paper-scissors.
This small feat is now promising to revolutionize current developments in the prosthetics.
Within the next four years, this team, contracted by DARPA, proposes to create a neurally integrated prosthetic arm that looks, feels and functions exactly like a flesh one.
"We're not trying to improve the capability. We're restoring function," Stuart D. Harshbarger, project manager for the APL, said. "It's more than just a little challenge -- it's hard to top the human limb."
"This is truly a `DARPA hard,' high-risk, high-reward project," Harshbarger continued. "We are going to need breakthrough research in neural control, sensory input, advanced mechanics and actuators, and prosthesis design and integration to pull this off in four years, when DARPA is expecting us to deliver the product, ready for clinical trials."
While advances in medicine have saved the lives of an increasing number of soldiers wounded in Operation Iraqi Freedom, the majority emerges with life-altering disfigurements involving the loss of limbs.
"We suddenly found ourselves with a number of young Americans who are badly injured and didn't have the prostheses they would need, or we would want them to have, in an ideal world," Geoffrey S.F. Ling, a physician and veteran of Iraq and Afghanistan who manages the program for DARPA, said."What's available commercially is woefully inadequate," he said. "We also set the bar really high. We want to give them back their lives."
"Our challenge is to advance the base of scientific understanding related to neural control mechanisms and physiological function of the human limb, while at the same time developing innovative engineering solutions that can be successfully implemented," Harshbarger said.
Research will focus on understanding neural control strategies that will let users operate the arm in a near-biological manner. Neurological control of the prosthetic arm takes advantage of several features of the human body that are retained even after a person suffers the loss of a limb. The motor cortex of the brain, for example, continues to fire and send nerve impulses down the spinal cord when an amputee pretends to move his or her missing arm. While the nerve impulses of an amputee terminate at the stump of the missing arm, these electrical signals can be harnessed by a simulated biological control panel for the missing arm, which is in turn integrated with the function of a prosthetic.
"We have handpicked a team that has decades of experience in prosthetics and related areas. We are literally standing on the shoulders of giants in their respective fields. This team comprises the best -- folks who've been pushing the envelope and are poised with many of their most recent advances finally ready to be implemented.
"Developing this broad consortium and providing both the technical and managerial leadership for the design and systems integration of this advanced limb is an example of what the APL does best," Dexter Smith, APL's business area executive for Biomedicine, commented. "We focus on programs where we can make critical contributions to our nation's critical challenges. I can think of no better example of a critical contribution than having a positive impact on the quality of life and future opportunities for our injured soldiers."
Critical to success of this effort is making sure the limb will be accepted and used by patients. Ross E. Andersen, associate professor of medicine at the JHU School of Medicine and team member of this project, is coordinating the patient outreach effort. "We will be working with the patient care community, including the amputee program at the U.S. Army Walter Reed Medical Center and with investigators at the [Hopkins] School of Public Health and the National Rehabilitation Hospital, to determine patient needs and develop measures of effectiveness in terms of cognitive loading during prosthetic use, functional performance, and patient acceptance at each step as we move forward," Andersen said. "This is a critical aspect of the program and ultimately demonstrates the importance of collaboration between the medical and scientific communities."
While Harshbarger hesitated from offering promises, he remains assured that "when it happens, it's literally going to revolutionize the prosthetics field and, more importantly, transform the lives of patients who have suffered limb losses."
