24/09/2015 10:38 BST | Updated 24/09/2016 06:12 BST

Paraplegic Walks Again After 'Amazing' Process To Reconnect Brain And Legs

A man able to walk again after scientists reconnected his brain and legs has spoken of the "amazing" process he went through.

Adam Fritz, who was confined to a wheelchair after severing his spinal cord in a motorcycle accident five years ago, said he hopes the technology will be adapted to help other people. 

It is the first time a paraplegic patient completely paralysed from the waist down after a spinal cord injury has been able to walk without relying on manually operated robotic limbs.

Neurosurgeons made the modern miracle possible by transmitting signals from the 26-year-old American's brain to a computer by Bluetooth, which sent messages to a belt around the man's waist, sending impulses to electrodes placed around both knees.

The "neural bypass" procedure generated impulses triggering movement that avoided the torn spinal cord.

Speaking to Sky News over an internet connection, Mr Fritz said: "What they did essentially was they used a computer to read my own brain waves and then they attached that to another computer that would shock my legs, almost creating a artificial nervous system, and then using that I was able to walk.

"It's really amazing and my hope is that other scientists will take this technology and adapt it for other individuals who have other ailments that we may not even have thought of when we started this journey."

After extensive training, Mr Fritz managed to step falteringly along a 12ft course while a harness and walking frame prevented him from falling. He was even able to hold a light conversation during the experiment, scientists said. 

US researcher Dr An Do, from the University of California at Irvine, who co-led the proof-of-concept study, said: "Even after years of paralysis the brain can still generate robust brain waves that can be harnessed to enable basic walking.

"We showed that you can restore intuitive, brain-controlled walking after a complete spinal cord injury. This non-invasive system for leg muscle stimulation is a promising method and is an advance of our current brain-controlled systems that use virtual reality or a robotic exoskeleton."

Learning how to walk again involved a 19-week multi-step training programme as Mr Fritz learned how to control a virtual reality "avatar" with his brain waves and was given exercises to recondition and strengthen his leg muscles.

Later he practised walking while suspended about 2in above the ground so his legs could move freely without having to be supported, and after 20 sessions he graduated to a body-weight support system to prevent falls.

Mr Fritz, dubbed the "mind walker", said: "It's complete concentration. You have to think about every single step when you're doing it.

"I mean, it's almost a foreign idea to have to concentrate that hard on walking, especially when you've been paralysed for several years. When you tell someone to walk when they are paralysed what does that mean?

"So I kind of almost had to relearn everything again to do this."

When spinal cord nerves are severed they cannot regenerate, usually resulting in life-long paralysis, so Mr Fritz's ability to take even one step is a major achievement.

Mr Fritz said: "I didn't realise when I first started doing this the impact it was going to have on everyone else, and when I first started I didn't realise it was going to be as successful as it was, so I kind of went into it very naive and now it is incredible to see where it is.

"I came to realise that just with this experiment that I did, that within my lifetime spinal cord injury will be a thing of the past, and that no one else will have to deal with it again, hopefully."

The results are reported in the Journal of NeuroEngineering and Rehabilitation. Further work is needed to establish whether the procedure can be used to restore a practical level of walking ability and help other patients.