Science and Technology News

Friday, February 3, 2012

WRNMMC Uses New, Brain-Controlled Prosthetic Arm

By Sarah Fortney, Walter Reed National Military Medical Center Public Affairs

Bethesda, Md. (NNS) -- A new prosthetic arm - operated by an individual's thoughts - was used by wounded warriors at the Walter Reed National Military Medical Center (WRNMMC) for the first time Jan. 24.

With nearly as much dexterity as a natural limb, 22 degrees of motion, and independent movement of fingers, the Modular Prosthetic Limb (MPL) was developed as part of a four-year program by the Johns Hopkins University Applied Physics Laboratory (APL), along with WRNMMC and the Uniformed Services University of the Health Sciences (USU). On Jan. 24, a wounded warrior began using the nine-pound device, maneuvering its metallic fingers and wrist.

"We've been working with [the APL] since the start of this project and we're very excited about the opportunity [to have] our first individual using this hand," said Col. (Dr.) Paul Pasquina, chief of Orthopaedics and Prosthetics at WRNMMC and director for the Center of Rehabilitation Sciences at USU. "We believe very strongly that those who are willing to put their lives in harm's way deserve the very best. Through this revolutionizing project, we've worked with the greatest manufacturers across the globe to come up with modern solutions to loss of an upper limb."

Pasquina explained the limb is controlled by surface electrodes, which pick up electric signals generated by the muscles underneath the skin, then convert those patterns in electrical signals into a robotic function.

"We wanted to make [the MPL] as intuitive as possible. Normally, when you move your hand, you think about moving your hand, and a signal comes down from your brain, goes down through your spinal cord, out through your limb and activates muscles in your hand to open or close [the hand]," Pasquina said.

With an amputee, the nerves traveling down the spinal cord are still intact, and they're still connected to some of the muscles in the arm, Pasquina said. "What we try to do is pick up the electrical signals of the muscles that still exist in the arm and interpret those, convert them to a computer signal to then drive a robotic limb," he said. "When an individual is thinking about closing their hand, muscles will activate and the prosthetic limb will respond accordingly."

Pasquina noted the potential future of this limb. Engineers seek to use electrodes underneath the skin for an electrical signal with much higher fidelity. Researchers also look to explore other mechanisms to rewire nerves.

"There are folks working very hard on electrical sensors that can go directly on nerves, and electrical sensors that can be embedded in the brain," he said. "It's very exciting to see that research and we've been privileged to partner with a lot of folks working on that. I think there's still a lot to be learned on how the human body can integrate with computers and computer interface, and I think the sky's the limit in terms of what we will do over the next five to ten years."

The next logical phase in the MPL's development is to incorporate sense of touch, and apply this technology to prosthetic legs in the future, said Cmdr. Jack Tsao, director of the Traumatic Brain Injury Programs for Navy Medicine's Bureau of Medicine and Surgery. A neurologist who also assisted in the project, Tsao said fortunately many amputees have expressed interest and seem willing to participate and help advance this research.

"What I think is fantastic is that we actually, because of this study, now have another option to treat amputees," said Tsao.

Before being fitted to use the device, Tsao explained amputees must first go through "training," using the Virtual Integrated Environment (VIE), which records an individual's muscle movements. By collecting their muscle data, the MPL is then suited for the individual. This gives the amputee time to learn how to use the device, fit them for it, then see how they work with it, he said.

Air Force Tech Sgt. Joe Delauriers, the first patient at WRNMMC to begin using the MPL, described the device as "pretty comfortable," and said he is grateful for the opportunity to be involved with the project.

"It's really fun working with the hand and [exciting] to see what's going to be coming in the future," said Delauriers. "Any input I can put into the program, to help them out, and future amputees, it's an honor for me. It's very rewarding."

Four months ago, Delauriers was injured by an IED blast in Afghanistan, which caused him to lose both his legs and part of his left arm. He said it's an indescribable feeling to be where he is today, thanks to advancements in care.

"I'm living off base, I'm driving, [and] I'm living with my [infant] son. I'm able to hold him without any open wounds, infections," he said. "They do such a great job here, with therapy. It's just amazing." The Airman said he can only imagine what these advancements will lead to in another decade.

"The technology is only going to keep getting better," said Tsao. "If guys like Joe can regain function, this would be revolutionizing to their lives, especially in the multiple limb amputees. Any degree of function and independence you can give back to someone is the most important thing." Pasquina also expressed his enthusiasm for this development, stating that he can recall when the device was merely a sketch on paper.

"It's something I still find amazing," Pasquina said. He is also amazed by the stories of the wounded warriors making such strides in their recovery.

"Time after time, you see people not only recover, but thrive after severe injuries, and they're inspirational to all of us, to us as medical staff who have the honor of taking care of them. It's humbling to be a part of that," he said.

Pasquina added that he'll continue his efforts to make this technology available to all service members and the population at large.

"The hand in itself is so important in terms of one's independence. Your ability to dress yourself, feed yourself, do self-grooming and hygiene is extremely important," said Pasquina. "Many of our injured service members were highly functioning, highly independent, had a great amount of responsibility. To now find themselves in a situation where they have an impairment or disability, that makes them less independent is something that not only affects them physically, but affects them emotionally. Anything we can do to [help] them be more independent and to regain that sense of self is something we're fully committed to doing and very excited about the opportunities that this presents."

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