WASHINGTON: A bionic prosthetic arm that is controlled by its operator’s thoughts and even restores some skin sensation to the amputee goes on display Thursday at a major US science conference.

More than 50 amputees worldwide, many of them military veterans whose limbs were lost in combat, have received such devices since they were first developed by US doctor Todd Kuiken in 2002.

The arm uses technology called Targeted Muscle Reinervation (TMR), which works by rerouting brain signals from nerves that were severed in the injury to muscles that are working and intact.

Glen Lehman, a retired US military sergeant who lost his arm in Iraq, was scheduled to demonstrate the latest technology at the annual conference of the American Association for the Advancement of Science.

“More than 20 years ago, I came to an understanding that current prostheses really fell short in their ability to enhance function and movement for amputees,” said Kuiken in a statement released ahead of the presentation.

“There was a significant unmet need to improve the lives of amputees, and I wanted to develop a technology that would help,” he said. “While much more progress is needed, we have taken significant steps to advance ability for amputees.” A series of other efforts to test and improve on these mind-reading robotics, known as brain-computer interfaces, were also to be showcased at the conference.

Among them, how researchers can now place computer chips on the surface of the brain to interpret neural activity, potentially allowing spinal cord injury patients to control a range of devices from computer games to prosthetics.

But while the technology may seem stunning, it is anything but easy work for the patients.

According to Jose del R. Millan and his team at the Ecole Polytechnique Federale de Lausanne in Switzerland, in a “typical brain-computer interface (BCI) set-up,” users send mental messages of either left, right, or no-command.

“But it turns out that no-command is very taxing to maintain and requires extreme concentration. After about an hour, most users are spent. Not much help if you need to maneuver that wheelchair through an airport,” his team said in a statement.

So now researchers are figuring out how to hook up a machine to interpret a user’s brain signals and read their intent.

Users are asked to read or speak aloud while thinking of as many left, right or no commands as possible. The technology learns to sift through the fray and figure out when a command has been delivered.

The result “makes multitasking a reality while at the same time allows users to catch a break.”