This Brain Computer Uses Your Jugular Like a USB Cable
A new way to insert neural implants doesn’t require brain surgery
Devices that would allow people to connect their brains directly to computers are getting a lot of attention from Silicon Valley lately. Last week, Facebook acquired the startup CTRL-Labs, which is developing a mind-reading wristband, and in July, Elon Musk’s Neuralink unveiled details about its brain chip, which the company eventually wants to embed in the brain through a quick procedure it compares to LASIK.
But Facebook and Neuralink’s plans to merge people with their devices will likely take several years to materialize. Wearables like what CTRL-Labs is developing rely on weaker neural signals and thus have shown less precise control. Brain implants promise more accuracy, but require highly specialized brain surgery, and pose a risk to patients.
Neurotechnology startup Synchron, based in Silicon Valley and Melbourne, Australia, may have found a way around these problems. The brain-computer interface company is testing whether a matchstick-sized neural implant that doesn’t require open brain surgery could allow paralyzed people the ability to control computers using only their thoughts.
“It conforms to the curvature of the blood vessel that we’re putting it into.”
In a clinical trial sponsored by Synchron, doctors in Australia have implanted the stent-like device for the first time in a person, a patient who is severely paralyzed from amyotrophic lateral sclerosis, or Lou Gehrig’s disease, and can’t move. Dubbed the Stentrode, the device is delivered to the brain using a catheter that is snaked through the jugular vein in the neck. The device is meant to travel all the way to the motor cortex, the “control center” of the brain that is responsible for controlling movement, but stays inside the blood vessel. The procedure takes about an hour, and only requires a small incision into the neck.
“Once we have deployed the Stentrode, it self-expands inside the blood vessel,” says Nicholas Opie, chief technology officer and co-founder of Synchron. “It conforms to the curvature of the blood vessel that we’re putting it into.” The idea is similar to coronary stents, which are commonly used to prop open blood vessels in patients with heart disease.
Formerly known as SmartStent, Synchron was founded in 2012 as a spinoff from the University of Melbourne after neurosurgeon Thomas Oxley pitched the Pentagon with a new idea for a brain-computer interface. In 2017, the company raised $10 million in an initial financing round, which included funding from the Defense Advanced Research Projects Agency. Its initial clinical trial will include five patients suffering from severe paralysis caused by a range of conditions, including spinal cord injury, stroke, muscular dystrophy, and motor neuron disease.
Like a heart stent, the Stentrode is a metallic mesh tube that is hollow, allowing blood to flow through freely. Sixteen electrodes or sensors built onto the device collect signals from neighboring neurons. Similar to how sound waves travel through wired headphones, neural signals are transmitted along an implanted wire that is threaded from the Stentrode to a pacemaker-style unit, about the size of a credit card, that is embedded under the skin in the chest. This second device transmits data wirelessly to a smartphone app to allow a person to communicate via text just by thinking about it.
Synchron’s Opie says patients will start by learning how to use the system to communicate using the app, which could take several weeks. The company eventually wants to train patients to employ the system to control their wheelchairs or robotic arms.
“One thing we’re trying to do is to not tell the patients what we want them to control but to ask them what they need and see what would be useful for them,” he says. “Then we’ll work with them to hopefully provide them with that.”
It’s a different approach than other experimental brain-computer interfaces that aim to allow paralyzed patients to control robotic arms and computers. These devices have required doctors to drill a hole in the patient’s skull to insert metal electrodes in the brain, opening up the risk of brain infection or inflammation. With those devices, scar tissue forms at the site of the implant over time, which can affect the quality of the recording. As a result, implantable brain-computer interfaces currently only last a few years. The Stentrode, by contrast, is designed to be a permanent brain implant.
“One thing we’re trying to do is to not tell the patients what we want them to control but to ask them what they need and see what would be useful for them.”
Robert Gaunt, a brain-computer interface researcher at the University of Pittsburgh who has been following the development of Synchron’s device, also notes that while the Stentrode might hold up for much longer in the brain, because it’s not implanted in the brain tissue, the number of independent signals that the device can pick up — known as the resolution — might be far fewer than those detected by penetrating devices.
In animal studies, the Stentrode was able to record high-quality brain signals in freely moving sheep for six months. (Sheep make for good test subjects because they have similar-sized blood vessels to humans.) Beyond that, it’s still unknown how long the device will work. Sheep studies also showed that the device could record neural information from numerous electrodes at once, and that the Stentrode was capable of extracting a similar amount of information as a traditional brain implant that’s placed in the brain tissue.
The Stentrode caused no inflammation in the sheep, and also wasn’t rejected by the brain — two problems that can occur with penetrating implants. The device is not without risks, though. Heart stents are known to cause blood clotting, which raises the risk of a heart attack or stroke.
The company hopes to ultimately gain approval from the Food and Drug Administration so it can offer the device to patients in the United States.
Gaunt says if the Stentrode works and is safe, it could potentially give more people access to brain-computer interfaces. “Because it’s based on a well-understood procedure, the ability to deploy this technology in hospital systems would be much easier than going into a place with a brand-new brain surgery that someone’s never seen before.”
