A ‘na-na-na-na-na’-Neuro-Controlled Bionic Arm allows its only amputee user to move his prosthetic arm simply by thinking it. Whereas he once lacked an arm, the device allows the user to be “better, stronger, faster” — the world’s first bionic man.

Researchers and scientists have long been trying to find a better way to communicate amputees’ brains with the reflexive movements of their missing parts, whether via implanted electrodes, microchips, detectors or drugs.

Doctors within the Neural Engineering Center for Artificial Limbs (NECAL) at the Rehabilitation Institute of Chicago (RIC) are currently working to refine a device that coordinates this task of allowing an amputee only to think about an arm movement — eating, shaving, fishing, vacuuming, putting on socks, picking up coffee, hugging + — at which point (thinking it) the arm dutifully moves.

The Neuro-Controlled Bionic Arm prototype, recently named by Popular Science magazine as one of its “Best of What’s New 2005,” is a myoelectric arm and is driven using electrical signals from an amputee’s healthy muscles, which allows the user to move his or her prosthetic arm by simply thinking it.

The design of the device and the procedure are impressive.

In a recent announcement, RIC claimed its bionic arm breakthrough as “the most advanced prosthesis of its kind today based on its precise, thought-powered movement and its greatest range of motion.”

In effect, as Popular Science summates, electrodes intercept the body’s vestigial nerve firings and feed them to a forearm-embedded computer, which then commands of six motors the movement of the device’s shoulder, elbow and hand in unison. Further, hand censors even allow the wearer to gauge pressure and fine-tune grip.

NECAL uses nerve-muscle grafts in amputees to gain added control signals for an artificial arm. Before the prosthetic is attached , nerves that used to go to the arm are procedurally removed and transferred to chest muscles; the nerves grow into chest muscles, so when the user thinks “close hand,” a portion of the chest muscle contracts, thus allowing the user to move the prosthetic arm as if it were a real arm.

Basically, the bionic arm is activated by the user’s own thought-generated nerve impulses. Via surface electrodes, these impulses are sensed from the healthy muscle and carried through to the mechanical arm, causing the arm to move.

Improving the function of artificial arms remains a considerable challenge, particularly for high-level amputations with greatest disability. Although there are externally powered hooks, hands, wrists and elbows, according to RIC, existing control methods are inadequate. At this time, most powered artificial limbs are controlled using myoelectric signals from a pair of muscles in the amputated limb — which allows only a single motion to be operated at a time, as operation of the terminal device; wrist and elbow must be performed sequentially — a slow, unnatural, coordination-lacking and altogether inefficient control method.

About eight percent of the estimated 387,500 amputees in the United States are those who have lost their arms, according to the Northwestern University Prostetic-Orthotic Center and previous CNN coverage.

Thus far, the “bionic arm” technology has been “very successful so far in both significantly improving the function of artificial limbs as well as allowing the skin to be re-innervated with nerves from the arm,” according to RIC.

For now, the prototype device fits only one man, Jesse Sullivan, who has been dubbed “the first bionic man.”

Sullivan, a Tennessee power company worker, lost both of his arms above the shoulder in a work-related accident four years ago. RIC doctors then offered him a bionic arm. “I didn’t really didn’t know what was available,” Sullivan told CNN. “It was a scary thing.

“I thought maybe it would be like the ‘Six Million Dollar Man’.”

The amputated nerve endings from Sullivan’s shoulder were grafted onto his pectoral muscle in his chest. As those nerves grew to innervate the chest muscles (after six months), the electrodes located over the graft began to pick up electrical signals reflecting the impulses and transmitting those to the mechanical prosthesis. The second-generation bionic arm provides Sullivan with greater function, movement and spontaneous control while its third generation aims to incorporate the sense of touch and feeling by next year.

A faster, more durable commercial version should be ready by 2008, but the ultimate goal is a robotic limb that functions as well as, if not better than, its human analogue.

Jesse Sullivan, patient profile

“Bionic Man” Jesse Sullivan, photo gallery

References

Neuro-Controlled Bionic Arm: The first prosthesis that merges mind and machine (Best of What’s New 2005)
Popular Science, November 2005
http://www.popsci.com/popsci/bown2005/personalhealth/19e6ee82ea447010vgnvcm1000004eecbccdrcrd.html

Brain waves drive man’s bionic arm
CNN, Sept. 25, 2003
http://www.cnn.com/2003/HEALTH/09/25/bionic.arm/index.html

Unveiling of World’s First “Bionic Man” by Rehabilitation Institute of Chicago is One of Many Technology Breakthroughs Anticipated During The Next Five Years
press release/corp. announcement
Rehabilitation Institute of Chicago (RIC), June 22, 2005
http://www.ric.org/research/pr_display.php?id=298

RIC Bionic Arm info.
http://www.ric.org/bionic/