Professor Nicholas Opie has seen it happen seven wonderful times. A paralysed patient has a tiny device implanted in the blood vessels in their brain. The device, known as the Stentrode, receives electrical signals from the brain, and as a result, the patient can control a computer with only their thoughts. So far, four people in Australia and three in the United States have shown how successful this system can be at allowing them to send emails and complete other online activities such as shopping.
“It’s exciting to see their faces when they use it for the first time,” says Opie, a biomedical engineer. “Partly because it’s novel – no-one’s been able to control computers with their mind before – but also because they can now live their lives with a level of independence.”
What’s been particularly moving is the impact on the patients’ carers and loved ones. “A wife of one of our patients was always hovering over him because he needed help all the time,” says Opie. “Now, he’s able to send her text messages, so she can go out into the garden or to the shops and not worry about him. It’s increased both of their independence.”
It’s been a big learning curve for Opie and his team, as the patients’ priorities turned out to be different from what they expected.
“We ‘able-bodied engineers’ thought, ‘This is what they’ll want to control,’” says Opie. “But we found out that they had slightly different ideas. They ask us if they can control other devices, such as their TV or lights, for example. We are fortunate to have worked with such enthusiastic and committed individuals, who have really assisted us in understanding where the biggest improvements to their lives can be made.”
Life-changing technology
The Stentrode, one of Time magazine’s Top 100 Inventions of 2021, has been under development for more than 10 years. Trials are currently underway in the United States to prove the safety of the technology (Opie says it’s safer than alternatives that involve open brain surgery).
The device is the first product developed by Synchron, a New York-based tech start-up founded in 2016 by Opie and Tom Oxley, an Australian vascular and interventional neurologist. Opie splits his time between Synchron and the University of Melbourne, where he heads up the Vascular Bionics Laboratory.
For Opie, The Stentrode is the culmination of his long-held interest in designing and inventing. His PhD, completed more than a decade ago at the University of Melbourne, focused on the Australian bionic eye project – a combined effort by universities and research institutions to develop, test and bring to market a device that uses electrical or light energy to stimulate visual impulses in visually impaired patients. “I was the surgical program coordinator [of the project] – like the interpreter between scientists and clinicians,” says Opie.
Opie continued this work at the Murdoch Children’s Research Institute in Melbourne, conceptualising a new medical apparatus that could help manage the treatment of children with cerebral palsy, by controlling the elasticity of their lower limbs.
Completing an MBA at the Melbourne Business School in 2018 has helped Opie develop his business acumen. “There was a gap in my knowledge about how businesses work,” he says. “A lot of people I met at uni were making amazing technology, but they didn’t know how to take the next step and translate their research into a commercial product.”
Inserting the device
A major challenge in developing the Stentrode was how to insert the device into a blood vessel within a 1mm diameter catheter and, when placed next to the motor cortex in the brain, how to make it expand to 6 or 7mm.
Opie and his team developed a tiny folding wire scaffold, which is inserted into the brain via the jugular vein, similar to how stents are used by surgeons to remove blood clots.
“We don’t have to do invasive surgery to access that part of the brain,” Opie explains. “We can use blood vessels, which makes it safer and a day procedure. It will also make it easier for us to scale up, because hospitals all around the world are already set up with staff who are trained for the procedure. The brain doesn’t try to reject it – it doesn’t even know we’re there, because we’re sort of ‘hiding’ in a blood vessel.”
Once in place, the Stentrode sends signals back via a wire to a port in the chest. This transmits the signals wirelessly to an external receiver. Over time, the body pushes the device and its wire to the side of the blood vessel and covers them with tissue, like what happens with a pacemaker.
Getting the patient to create the right brain signals to control commands on a computer has involved a bit of trial and error for both the team and the patients, says Opie. It took the first patient 40 days to achieve a mouse click, for example; the second patient learned it in a week. Each patient since then has mastered a mouse click on the first day.
Rather than instructing the patients to “think about tapping your right ankle” or “try thinking about moving your left leg”, Opie says they give them a few starting ideas and let them discover what works for them. “We say, don’t listen to us, do what you need to do.”
Embracing differences
The motor cortex is slightly different in each person, says Opie, which means every patient will respond to the Stentrode differently.
“For example, a pianist might have a really good map of every muscle in their fingers, whereas a soccer player might have better mapping of their lower limbs. So, it might be imagining moving your left hand or right hand to control the mouse button,” says Opie.
“If we know they can move their left leg to get a command, it’ll be the same every day after, so you don’t have to recalibrate it every day, like some other technologies. The patient can wake up and start using it straight away, without us being there.”
Synchron has some 45 staff in the United States, working on patient recruitment and gaining commercial approval from the Food and Drug Administration. In Australia, another 15 or so staff are looking at more potential uses of the device, for example, if it can be used to send an electrical signal to the brain to prevent epileptic seizures. “That’s a future application that we’re excited about,” says Opie.
Many able-bodied people are also interested in the possibilities. “I think this is one of those technologies where a lot of people have ideas about being able to control things with their minds,” says Opie. “I can see lots of broader interest in the community. Gamers are interested if they can reduce the lag between the mind and the hand.”
Follow Professor Nicholas Opie on LinkedIn
Story by Ken Eastwood