Bionic Hand

PART 2

Kitts is living proff that, even though the flash and bone may be damaged or gone, the nerves and parts of the brain that once controlled it live on. In many patients, they sit there waiting to communicate-dangling telephone wires, severed from a handset. With microscopic electrodes and surgical wizardry  doctors have begun to connect these parts in other patients to devices such as cameras and microphones and motors. As a result, the blind can see, the deaf can hear, and Amanda Kitts can fold her shirts.

Kitts is one of "tomorrow's people", a group whose missing or ruined body parts are being replaced by devices embedded in their nervous systems that respond to commands from their brains. The  machines they use are called neural prostheses or-as scientists have become more comfortable with a arm made popular by science fiction writers- bionics. Eric Schremp, who has been a quadriplegic since he shattered his neck during swimming pool dive in 1992, now has an electronic device under his skin that mind and machine an array of sensors tracks muscle movements that Amanda Kitts produces in her residual arm thanks to surgically rerouted nerves. Next generation prostheses obey relayed signals, increasingly working like her original limb. Lets him move his fingers to grip s fork. Jo Ann Lewis, a blind woman, can see the shapes of trees with the help of a tiny camera that communicates with the her optic nerve. And Tammy Kenny cans peak to her 18-month-old son, Aiden,and he can reply, because the boy, born deaf, has 22 electrodes inside his ear that change sounds picked up by a microphone into signals his auditory nerve can understand.

The work is extremely delicate, a series of trials fills with many errors. As scientists have learned that it's possible to link machine and mind, they have also learned how difficult it so to maintain that connection. If the cup atop Kitts arm shifts just slightly, for instance, she might not be able to close her fingers. Still, bionics represents a big leap forward, enabling researchers when Kitts thinks about flexing her elbow, the phantom moves, and the artificial elbow bends. "I don't really think about it. I just move it, "she says. To give people back much moreof what they've lost than was ever possible before.

"That's rally what this work is about : restoration," says Joseph Pancrazio, program director for neural engineering at the National Institute of Neurological Disorders and Stroke. "When a person with a spinal-cord injury can be in a restaurant, feeding himself, and no one else notices, that is my definition of success."

to be continued ......