Before Ms. Kitts had the reinnervation procedure in October 2007, for example, she had to move her back muscles a certain way to make the wrist rotate, and flex her triceps and biceps to move the elbow up and down. “It was a lot of work,” she said. “It wasn’t useful to me at all.”

Image Amanda Kitts lost her arm in a car accident in 2006, but a new kind of prosthetic allows her to tie shoes at her day care center. Credit... Shawn Poynter for The New York Times

The reinnervation method is part of a recent explosion of new ideas and techniques being explored as scientists try to help people better compensate for missing limbs or paralysis. The drive is being fueled by increasing amputations from diabetes and military injuries and by advances in technology.

Arms have become a particular focus. Science has long had success with prosthetic legs, but it is harder to mimic the complexity and dexterity of hands and arms. Efforts under way include more flexible and sensitive skin and arm designs, and wireless devices implanted in prosthetic arms to allow more natural movement. Researchers have also used sensors implanted in the brain to enable two monkeys to control a mechanical arm, and a paralyzed man to move a cursor on a computer screen.

Some of these methods, if perfected and if approved by regulatory agencies, may eventually become more viable for amputees. And while the reinnervation technique does not require regulatory approval because it is done with surgery and existing devices, it has limitations that even its creator acknowledges, including that it is not possible for every patient, is costly, and takes months for the rewired nerves to grow and become effective.

Still, experts say it is the most advanced system being used in actual patients that allows the nervous system to directly control movement of an artificial arm. Since it was pioneered in 2001 by Todd Kuiken, a physiatrist and biomedical engineer at the Rehabilitation Institute of Chicago, it has been performed on about 30 people in the United States, Canada and Europe, including eight soldiers injured in Iraq or Afghanistan.

Many patients, including the first, Jesse Sullivan, an electrical worker from Tennessee who lost both arms when he was electrocuted by a wire, can not only manipulate their prosthetic arms, but feel sensations of their missing hand when their chest is touched, Dr. Kuiken said.