Bionic Hand

Amanda Kitts is mobbed by four and five year old as she enters the classroom at the Kiddie Kotage Learning Center near Knoxville, Tennessee. "Hey kids, how're my babies today?" she say, patting shoulders and ruffling hair. Slender and energetic, she has operated this day care center and two others for almost 20 years. She crouches down to talk to a small girl, putting her hands on her knees. "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 finger. What be brushes against is flesh-colored plastic, finger 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 Kitt'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 in tact 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 excitedall the time, because they keep on improving the arm. One day I'LL be able to feel things with it and clap my hands togetherin time to the songs my kids are singing

to be continued ......