Bionic implant ‘could enable the paralysed to walk again’

Stroke and spinal cord injuries are leading causes of disability affecting 1 in 50 people. Picture Shutterstock
Stroke and spinal cord injuries are leading causes of disability affecting 1 in 50 people. Picture Shutterstock

The world’s first ‘bionic spinal cord” that could enable paralysed patients to walk again using the power of thought has been developed.

It involves inserting a brain implant about the size of a small paperclip to control an exoskeleton or prosthetic limbs - and has been hailed as the ‘holy grail’ in bionics.

It works by decoding brain activity responsible for movement - training a computer to recognise those signatures and then activating robotic limbs when these are registered.

The device - an electrode called the ‘stentrode’ - is fitted with a tube without the need for risky open surgery. Human trials are to be carried out on three people next year.

It reads electrical signals from the motor cortex - the brain’s control centre. These can then be transmitted to an exoskeleton or wheelchair to give paraplegics greater mobility.

Over time, it’s believed it will become second nature - like driving or playing the piano.

The device records neural activity that has been shown in pre-clinical trials to move limbs through an exoskeleton.

The first participants will be selected from the Austin Health Victorian Spinal Cord Unit in Australia and fitted with the stentrode at The Royal Melbourne Hospital in 2017.

Described in the journal Nature Biotechnology, it’s capable of recording high-quality signals emitted from the motor cortex.

Dr Thomas Oxley, a neurologist at The Royal Melbourne Hospital, said the stentrode was revolutionary.

He said: “We’ve been able to create the world’s only minimally invasive device that is implanted into a blood vessel in the brain via a simple day procedure - avoiding the need for high risk open brain surgery.

“Our vision - through this device - is to return function and mobility to patients with complete paralysis by recording brain activity and converting the acquired signals into electrical commands which in turn would lead to movement of the limbs through a mobility assist device like an exoskeleton. In essence this a bionic spinal cord.”

Stroke and spinal cord injuries are leading causes of disability affecting 1 in 50 people.

Dr Nicholas Opie, of Melbourne University, said the concept was similar to an implantable cardiac pacemaker - electrical interaction with tissue using sensors inserted into a vein but inside the brain.

He said: “Utilising stent technology our electrode array self-expands to stick to the inside wall of a vein enabling us to record local brain activity.

“By extracting the recorded neural signals we can use these as commands to control wheelchairs, exoskeletons, prosthetic limbs or computers.

“In our first-in-human trial - that we anticipate will begin within two years - we are hoping to achieve direct brain control of an exoskeleton for three people with paralysis.

“Currently exoskeletons are controlled by manual manipulation of a joystick to switch between the various elements of walking - stand, start, stop, turn. The stentrode will be the first device that enables direct thought control of these devices.”

Prof Clive May, of Melbourne University, said the data from the pre-clinical study highlighted the implantation of the device was safe for long-term use.

He said: “Through our pre-clinical study we were able to successfully record brain activity over many months. The quality of recording improved as the device was incorporated into tissue.

“Our study also showed it was safe and effective to implant the device via angiography which is minimally invasive compared with the high risks associated with open brain surgery.

“The brain-computer interface is a revolutionary device that holds the potential to overcome paralysis, by returning mobility and independence to patients affected by various conditions.”

Prof Terry O’Brien, of The Royal Melbourne Hospital, said the stentrode is the “holy grail” for research in bionics.

He said “To be able to create a device that can record brainwave activity over long periods of time without damaging the brain is an amazing development in modern medicine.

“It can also be potentially used in people with a range of diseases aside from spinal cord injury including epilepsy, Parkinson’s and other neurological disorders.”

There is currently no treatment for spinal cord injury right now, only rehab.