Kate Jorgenson has played volleyball and basketball and swum competitively without her left arm, which she lost above the elbow in an ATV accident two years ago.
But then there are tasks such as eating a Dairy Queen Blizzard.
To dig out the thick, cookie dough ice cream, the 13-year-old from Westbrook, Minn., had to steady the cold cup between her knees, sometimes making a mess in the process.
"It's things like that you and I take for granted," said her father, Jim.
And that's where a new type of bionic prosthesis — aided by a surgery that reassigns nerves in the arm — has made a big difference in the teenager's life. While she is still learning to master the prosthesis, Jorgenson can now use it to mix muffin batter, zip up a jacket and carry shopping bags while texting friends.
"She hadn't zipped a zipper for almost two years," said her mother, Nikki Jorgenson. "She had to ask us to do it. For teenagers, that's frustrating."
Hastened by advances in neurology and robotics — and tragically by the spike in U.S. soldiers returning from Iraq and Afghanistan without limbs — a new era of prosthetics has emerged, using signals from the brain to evoke an increasing variety of movements from bionic limbs.
Jorgenson is one of about 50 patients worldwide — and the youngest, so far — to undergo a surgery called targeted muscle reinnervation, in which severed nerve endings in her arm were reassigned to control muscles that would trigger sensors in the bionic arm. With the surgery, which was performed last year at the Mayo Clinic, she also became the first to have six nerves rewired, giving her the ability at will to move the robotic elbow up and down, rotate the wrist, and open and close the hand.