When electrician Rickard Normark lost his left arm after being electrocuted at work in 2011, he thought he had no other option than to endure the pain and discomfort of a conventional prosthesis. It would often slip off during his daily activities, and he scratched the irritated skin under the socket so much with his healthy hand that it began to lose sensation.

Then three years ago, Normark received a new kind of brain-controlled prosthetic that was surgically attached to the bone, muscles, and nerves of his upper arm, allowing him to not only grip objects intuitively with his hand but feel the sensation of touching them.

“You cannot even compare how things have changed for me,” Normark, 47, told STAT from his home in Sweden. “The socket prosthesis I previously had is a tool you can use for help in your daily life, but this … this is a part of you.”


This advanced prosthetic, described in a paper published Wednesday in the New England Journal of Medicine, represents an advance over other mind-controlled prosthetic limbs under development, the researchers said.

For one, all electronics are contained within the prosthesis, which removes the need for external equipment, such as wires, electrodes, or batteries. The prosthetic hand is controlled using electrodes implanted in the muscles of the upper arm, to which nerves involved in opening and closing the hand have been rerouted. Second, force sensors embedded in the thumb of the hand provide sensory feedback while grasping objects. Those signals are relayed through wires connected to nerves in the upper arm, and then to the brain, where they are perceived as pressure against the hand.


The scientists report on four Swedish patients who have lived with this new technology for between three and seven years. Normark is one of them. He’s been able to race and repair cars with the improved hand control afforded by the new prosthesis. The others reported being able to canoe, ice-fish, and ride a snowmobile.

“All patients reported having greater trust in their prosthesis since the intervention, referred to it as being part of themselves, and reported positive effects on their self-esteem, self-image, and social relations,” the authors wrote.