Implantable electrode may enable mind-control of bionic limbs

A new device designed to allow patients suffering from paralysis to regain the ability to move by using their thoughts to power bionic limbs or exoskeletons will its inaugural in-human trials next year in Australia, researchers at The Royal Melbourne Hospital announced Monday.

The interface is comprised of a stent-based electrode or “stentrode” that is implanted in a blood vessel within the patient’s brain, and is used to record type of neural activity that a brain uses to control motion-assist technology, doctors at the Victoria-based medical facility explained.

The decision to move forward with in-patient trials comes following the publication of research in the latest edition of Nature Biotechnology, in which neurologist Dr. Thomas Oxley and his co-authors demonstrated that the unit is capable of recording the high-quality signals emitted by the brain’s motor cortex – without requiring patients to undergo open-brain surgery.

Stentrode unit essentially acts like a ‘bionic spinal cord’

In a statement, Dr. Oxley called the paperclip-sized stentrode a revolutionary device, adding that it is “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.”

Dr. Oxley, who in addition to his work at The Royal Melbourne Hospital is a research fellow at The Florey Institute of Neurosciences and the University of Melbourne, said that his team hopes that the stentrode will be able to “return function and mobility to patients with complete paralysis by recording brain activity and converting the acquired signals into electrical commands.”

This, in turn, would result in movement of the limbs through a mobility-assist device such as an exoskeleton or a bionic limb, creating what is essentially “a bionic spinal cord.” The trial is set to begin at The Royal Melbourne Hospital sometime in 2017 and will involve patients chosen from the Austin Health Victorian Spinal Cord Unit, the authors explained in Monday’s statement.

According to the researchers, stroke and spinal cord injuries affect one out of every 50 men and women, and are the leading causes of disability. There are an estimated 20,000 Australians who suffer from spinal cord injuries and another 150,000 facing post-stroke mobility issues that could benefit from the stentrode technology, which University of Melbourne biomedical engineer and co-lead investigator Dr. Nicholas Opie compared to an implantable cardiac pacemaker.

Technology could also help epilepsy, Parkinson’s patients

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

“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,” added neurophysiologist and co-author Professor Clive May. “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.”

Professor Terry O’Brien, Head of Medicine at Departments of Medicine and Neurology at The Royal Melbourne Hospital and University of Melbourne, called the stentrode’s development the “holy grail” of bionics research, adding that creating a device capable of recording brain activity without damaging the brain itself is “amazing development in modern medicine” that could also be used to treat epilepsy, Parkinsons and other neurological conditions.

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Feature Image: University of Melbourne