25 January 2010

Changing lives with bionics

Twenty motors animate a cutting-edge bionic arm that mimics a flesh-and-blood limb with unprecedented accuracy. Users control it via nerve impulses. It even has sensors that register touch.

Fascinating feature article about bionics in this month's National Geographic.

"The robot arm!" several kids cry.

"You remember this, huh?" says Kitts, holding out her left arm. She turns her hand palm up. There is a soft whirring sound. If you weren't paying close attention, you'd miss it. She bends her elbow, accompanied by more whirring.

"Make it do something silly!" one girl says.

"Silly? Remember how I can shake your hand?" Kitts says, extending her arm and rotat­ing her wrist. A boy reaches out, hesitantly, to touch her fingers. What he brushes against is flesh-colored plastic, fingers curved slightly inward. Underneath are three motors, a metal frame, and a network of sophisticated electronics. The assembly is topped by a white plastic cup midway up Kitts's biceps, encircling a stump that is almost all that remains from the arm she lost in a car accident in 2006.

Almost all, but not quite. Within her brain, below the level of consciousness, lives an intact image of that arm, a phantom. When Kitts thinks about flexing her elbow, the phantom moves. Impulses racing down from her brain are picked up by electrode sensors in the white cup and converted into signals that turn motors, and the artificial elbow bends.

"I don't really think about it. I just move it," says the 40-year-old, who uses both this standard model and a more experimental arm with even more control. "After my accident I felt lost, and I didn't understand why God would do such a terrible thing to me. These days I'm just excited all the time, because they keep on improving the arm. One day I'll be able to feel things with it and clap my hands together in time to the songs my kids are singing."

Kitts is living proof that, even though the flesh and bone may be damaged or gone, the nerves and parts of the brain that once controlled it live on.

Scroll through the accompanying photo gallery and you'll see just how the bionic arm works. You'll also learn about exciting developments with bionic eyes, ears, and see Iraq veteran Lt. Col. Greg Gadson's motorized legs.

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