Amanda Kitts lost her left arm in a car accident three years ago, but these days she plays football with her 12-year-old son, and changes diapers and bearhugs children at the three Kiddie Cottage day care centers she owns in Knoxville, Tenn.

Ms. Kitts, 40, does this all with a new kind of artificial arm that moves more easily than other devices and that she can control by using only her thoughts. Her turnaround is the result of a new procedure that is attracting increasing attention because it allows people to move prosthetic arms more automatically than ever before, simply by using rewired nerves and their brains.

>>>> article in New York Times