New device to allow paralysed people control bionic limbs

 The world's first minimally invasive brain-machine interface dubbed as 'bionic spinal cord' that offers paralysed people hope of walking again using the power of thought has been developed, scientists said today.

The device consists of a stent-based electrode (stentrode), which is implanted within a blood vessel next to the brain, and records the type of neural activity that has been shown in pre-clinical trials to move limbs through an exoskeleton or to control bionic limbs.

The new device is the size of a small paperclip and will be implanted in the first in-human trial at The Royal Melbourne Hospital in 2017.

The results show the device is capable of recording high-quality signals emitted from the brain's motor cortex, without the need for open brain surgery.

"We have 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," said principal author Thomas Oxley, a neurologist at the Royal Melbourne Hospital.

"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," said Oxley, also a research fellow at University of Melbourne.

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

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

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

"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," he said.
"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," he said.

"Our study also showed that 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," said Clive May, from the The Florey Institute of Neurosciences.
The study was published in the journal Nature Biotechnology.