Scientists have been able to use wireless brain implants to enable two paralysed monkeys to walk again.

The team of scientists at the Swiss Federal Institute of Technology implanted the device into the part of the monkeys’ brain that controls movement. The implant received instructions then sent out signals to the nerves controlling leg movement in the monkeys.

The system represents the first time a neural prosthetic — a series of devices that link brain signals to prosthetic devices — has restored movement, raising hope for development of radical new therapies for people with spinal injuries.

In the study published in the science journal Nature, a computer deciphered decoded brain signals then sent instructions to the implant in the monkey’s spine to electrically stimulate the relevant nerves. One monkey regained the ability to walk in a straight line on a treadmill six days after it was partially paralysed after a surgical procedure that separated some of the nerves that controlled its right hind leg.

“It was a big surprise for us,” said Grégoire Courtine, a neuroscientist who led the research. “The monkey’s gait was not perfect, but it was almost like normal walking. The foot was not dragging and it was fully weight bearing.”

While the implant has only been tested on monkeys, so far, the scientists said the technology could be ready for human trials within a decade.

“The system we have developed uses signals recorded from the motor cortex of the brain to trigger co-ordinated electrical stimulation of nerves in the spine, which are responsible for movement,” said engineer David Borton from Brown University. “With the system turned on, the animals in our study had nearly normal movement.”

When walking, electrical signals, which originate in the brain’s motor cortex — the region involved in the planning, control, and execution of voluntary movements — are sent down to the lower part of the back region in the lower spinal cord. However, spinal-cord injuries block the flow of electrical signals from the brain to the rest of the body resulting in paralysis. This type of paralysis is difficult to heal, but a potential solution is to use technology to bypass the injury.

This achievement is the latest in a series of rapid advances in the field of neuroprosthetics, as engineers and neuroscientists use tiny implants to decode signals from the brain and relay them to other parts of the body.

Earlier this year, researchers at the University of Pittsburgh and the University of Pittsburgh Medical Centre implanted an electrode smaller than a grain of sand in the brain of a paralysed man, which allowed him to experience the sense of touch with a mind-controlled robotic arm.