A US man paralysed from his shoulders for eight years has temporarily managed to regain control of a limb using thought-control technology.

Bill Kochevar, who was injured in a bicycling accident, can now grasp and lift objects.

He is believed to be the first person in the world with quadriplegia to have arm and hand movement restored by two kinds of implant.

Kochevar, 56, from Cleveland, Ohio, said: “For somebody who’s been injured eight years and couldn’t move, being able to move just that little bit is awesome to me.

“It’s better than I thought it would be.”

Principal investigator Dr Bob Kirsch, from Case Western Reserve University in the US, said: “He’s really breaking ground for the spinal cord injury community.

“This is a major step toward restoring some independence.”

So how does it work?

(Case Western Reserve University)

Electrodes under his skull record the activity of brain neurons to generate signals that tell another device to stimulate muscles in the paralysed limb.

A team of surgeons implanted two pill-sized 96-channel electrode arrays on the surface of the motor cortex region of Kochevar’s brain.

The arrays record brain signals generated by imagined movements of the arm and hand.

Information about movements Kochevar intends to make are filtered out of the signals and used to command the functional electrical stimulation (FES) muscle activation system.

Did it require advanced planning?

(Case Western Reserve University)

In preparation, Kochevar first learned how to use his brain signals to move a virtual-reality arm on a computer screen.

“He was able to do it within a few minutes,” said Dr Kirsch said. “The code was still in his brain.”

After four months of practice, it was time for him to take control of his own arm and hand.

At that stage the 36-electrodes of the FES device were implanted in Kochevar’s upper and lower right arm.

(Case Western Reserve University)

Pulses sent through the electrodes trigger muscles regulating movement of the hand, wrist, arm, elbow and shoulder.

To counterbalance the force of gravity, which would otherwise drag his arm down, Kochever was fitted with a mobile support also under his brain’s control. Using the system, Kochevar is able to activate his muscles in a co-ordinated fashion.

He told the researchers: “I’m making it move without having to really concentrate hard at it… I just think ‘out’… and it goes.”

A report on his progress appears in the latest issue of The Lancet medical journal.