New device to get people with paralysis back on their feet
MELBOURNE, Australia: Melbourne medical researchers have created a new minimally invasive brain–machine interface, giving people with spinal cord injuries new hope of walking again with the power of thought. The new device is the size of a small paper clip and will be implanted in the first human trial at the Royal Melbourne Hospital in 2017.
The brain–machine interface consists of a stent-based electrode (stentrode) that is implanted into a blood vessel in the brain and records the type of neural activity that has been shown in preclinical trials to move limbs via an exoskeleton or to control bionic limbs. In a recent study, the researchers found that the device is capable of recording high-quality signals emitted from the brain’s motor cortex without the need for open-brain surgery.
The stentrode is revolutionary, according to Dr Thomas Oxley, principal author, neurologist at the Royal Melbourne Hospital, as well as research fellow at the Florey Institute of Neuroscience and Mental Health and the University of Melbourne. “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,” he stated.
In total, 39 academic scientists from 16 departments in medical research from the hospital, the university and the Florey Institute were involved in the development of the stentrode.
With the device, the researchers hope to return function and mobility to patients with complete paralysis by recording brain activity and converting the acquired signals into electrical commands. These commands could enable movement of the limbs through a mobility assist device such as an exoskeleton. “In essence this a bionic spinal cord,” Oxley explained.
Stroke and spinal cord injuries are leading causes of disability, affecting one in 50 people. There are 20,000 Australians with spinal cord injuries, with the typical patient a 19-year old male, and about 150,000 Australians left severely disabled after stroke.
Co-principal investigator and biomedical engineer at the University of Melbourne Dr Nicholas Opie said that the concept was similar to an implantable cardiac pacemaker: electrical interaction with tissue using sensors inserted into a vein, but inside the brain. “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,” Opie explained.
“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,” Opie stated. “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.”
According to the scientists, the development of the stentrode has been the holy grail for research in bionics. “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,” said Prof. Terence O’Brien, head of medicine at departments of medicine and neurology at the Royal Melbourne Hospital and the University of Melbourne. “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,” he added.
The study, titled “Minimally invasive endovascular stent-electrode array for high-fidelity, chronic recordings of cortical neural activity”, was published online on 8 February in the Nature Biotechnology journal.