Synchron's BCI implants may help paralyzed patients reconnect with the world

Dr. Tom Oxley visibly stiffens at the prospect of using brain-computer interface technology for something as gauche as augmenting able-bodied humans. “We're not building a BCI to control Spotify or to watch Netflix,” the CEO of medical device startup Synchron tersely told Engadget via videocall last week.

“There's all this hype and excitement about BCI, about where it might go,” Oxley continued. “But the reality is, what's it gonna do for patients? We describe this problem for patients, not around wanting to super-augment their brain or body, but wanting to restore the fundamental agency and autonomy that [able-bodied people] take for granted.”

Around 31,000 Americans currently live with Amyotrophic lateral sclerosis (ALS) with another 5,000 diagnosed every year. Nearly 300,000 Americans suffer from spinal cord paralysis, and another approximately 18,000 people join those ranks annually. Thousands more are paralyzed by stroke and accident, losing their ability to see, hear or feel the world around them. And with the lack of motor control in their extremities, these Americans can also lose access to a critical component of modern life: their smartphone.

“[A smartphone] creates our independence and our autonomy,” Oxley said. “It's communicating to each other, text messaging, emailing. It's controlling the lights in your house, doing your banking, doing your shopping, all those things.”

“If you can control your phone again,” he said. “you can restore those elements of your lifestyle.”

So while Elon Musk promises an fantastical cyberpunk future where everybody knows Kung Fu and can upload their consciousness to the cloud on a whim, startups like Synchron, as well as Medtronic, Blackrock Neurotech, BrainGate and Precision Neuroscience and countless academic research teams, are working to put this transformative medical technology into clinical practice, reliably and ethically.

The best way to a man’s mind is through his jugular vein

Brooklyn-based Synchron made history in 2022 when it became the first company to successfully implant a BCI into a human patient as part of its pioneering SWITCH study performed in partnership with Mount Sinai Hospital. To date, the medical community has generally had just two options in capturing the myriad electrical signals that our brains produce: low-fidelity but non-invasive EEG wave caps, or high-fidelity Utah Array neural probes that require open-brain surgery to install.

Synchron’s Stentrode device provides a third: it is surgically guided up through a patient’s jugular vein to rest within a large blood vessel near their motor cortex where its integrated array of sensors yield better-fidelity signal than an EEG cap without the messy implantation or eventual performance drop off of probe arrays.

“We're not putting penetrative electronics into the brain and so the surgical procedure itself is minimally invasive,” Dr. David Putrino, Director of Rehabilitation Innovation for the Mount Sinai Health System, explained to Engadget. “The second piece of it is, you're not asking a neurologist to learn anything new ... They know how to place stents, and you're really asking to place a stent in a big vessel — it's not a hard task.”

“These types of vascular surgeries in the brain are commonly performed,” said Dr. Zoran Nenadić, William J. Link Chair and Professor of Biomedical Engineering at the University of California, Irvine. “I think they're clever using this route to deliver these implants into the human brain, which otherwise is an invasive surgery.”

Though the Stentrode’s signal quality is not quite on par with a probe array, it doesn’t suffer the signal degradation that arrays do. Quite the opposite, in fact. “When you use penetrative electrodes and you put them in the brain,” Putrino said, “gliosis forms around the electrodes and impedances change, signal quality goes down, you lose certain electrodes. In this case, as the electrode vascularizes into the blood vessel, it actually stabilizes and improves the recording over time.”

A device for those silent moments of terror

“We're finally, actually, paying attention to a subset of individuals with disabilities who previously have not had technology available that gives them digital autonomy,” Putrino said. He points out that for many severely paralyzed people, folks who can perhaps wiggle a finger or toe, or who can use eye tracking technology, the communication devices at their disposal are situational at best. Alert buttons can shift out of reach, eye tracking systems are largely stationary tools and unusable in cars.

“We communicate with these folks on a regular basis and the fears that are brought up that this technology can help with,” Putrino recalls. “It is exactly in these silent moments, where it's like, the eye tracking has been put away for the night and then you start to choke, how do you call someone in? Your call button or your communication device is pushed to the side and you see the nurse starting to prepare the wrong medication for you. How do you alert them? These moments happen often in a disabled person's life and we don't have an answer for these things.”

With a BCI, he continued, locked-in patients are no longer isolated. They can simply wake their digital device from sleep mode and use it to alert caregivers. ”This thing works outside, it works in different light settings, it works regardless of whether you're laying flat on your back or sitting up in your chair,” Putrino said. “Versatile, continuous digital control is the goal.”

Reaching that goal is still at least half a decade away. “Our goal over the next five years is to get market approval and then we’ll be ready to scale up that point,” Oxley said. The rate of that scaling will depend on the company’s access to cath labs. These are facilities found in both primary and secondary level hospitals so there are thousands of them around the country, Oxley said. Far more than the handful of primary level hospitals that are equipped to handle open-brain BCI implantation surgeries.

A show of hands for another hole in your head

In 2021, Synchron conducted its SWITCH safety study for the Stentrode device itself, implanting it in four ALS patients and monitoring their health over the course of the next year. The study found the device to be “safe, with no serious adverse events that led to disability or death,” according to a 2022 press release. The Stentrod “stayed in place for all four patients and the blood vessel in which the device was implanted remained open.”

Buoyed by that success, Synchon launched its headline-grabbing COMMAND study last year, which uses the company’s entire brain.io system in six patients to help them communicate digitally. “We’re really trying to show that this thing improves quality of life and improves agency of the individual,” Putrino said. The team had initially expected the recruitment process through which candidate patients are screened, to take five full years to complete.

Dr. Putrino was not prepared for the outpouring of interest, especially given the permanent nature of these tests and quality of life that patients might expect to have once they're in. “Many of our patients have end-stage ALS, so being part of a trial is a non-trivial decision,” Putrino said. “That's like, do you want to spend what maybe some of the last years of your life with researchers as opposed to with family members?”

“Is that a choice you want to make for folks who are considering the trial who have a spinal cord injury?” asked Putrino, as those folks are also eligible for implantation. “We have very candid conversations with them around, look, this is a gen one device,” he warns. “Do you want to wait for gen five because you don't have a short life expectancy, you could live another 30 years. This is a permanent implant.”

Still, the public interest in Synchron’s BCI work has led to such a glut of interested patients, that the team was able to perform its implantation surgery on the sixth and final patient of the study in early August — nearly 18 months ahead of schedule. The team will need to continue the study for at least another year (to meet minimum safety standards like in the previous SWITCH study) but has already gotten permission from the NIH to extend its observation portion to the full original five years. This will give Synchron significantly more data to work with in the future, Putrino explained.

How we can avoid another Argus II SNAFU

Our Geordi LaForge visor future seemed a veritable lock in 2013, when Second Sight Medical Products received an FDA Humanitarian Use Device designation for its Argus II retinal prosthesis, two years after it received commercial clearance in Europe. The medical device, designed to restore at least rudimentary functional vision to people suffering profound vision loss from retinitis pigmentosa, was implanted in the patient’s retina and converted digital video signals it received from an external, glasses-mounted camera into the analog electrical impulses that the brain can comprehend — effectively bypassing the diseased portions of the patient’s ocular system.

With the technical blessing of the FDA in hand (Humanitarian Use cases are not subject to nearly the same scrutiny as full FDA approval), Second Sight filed for IPO in 2013 and was listed in NASDAQ the following year. Seven years after that, the company went belly up in 2020, declared itself out of business and wished the best of luck to the suckers who spent $150k to get its hardware hardwired into their skulls.

“Once you're in that [Humanitarian Use] category, it's kind of hard to go back and do all of the studies that are necessary to get the traditional FDA approvals to move forward,” Dr. An Do, Assistant Professor in the Department of Neurology at University of California, Irvine, told Engadget. “I think the other issue is that these are orphan diseases. There's a very small group of people that they're catering to.”

As IEEE Spectrum rightfully points out, one loose wire, one degraded connection or faulty lead, and these patients can potentially re-lose what little sight they had regained. There’s also the chance that the implant, without regular upkeep, eventually causes an infection or interferes with other medical procedures, requiring a costly, invasive surgery to remove.

“I am constantly concerned about this,” Putrino admitted. “This is a question that keeps me up at night. I think that, obviously, we need to make sure that companies can in good faith proceed to the next stage of their work as a company before they begin any clinical trials.”

He also calls on the FDA to expand its evaluations of BCI companies to potentially include examining the applicant’s ongoing financial stability. “I think that this is definitely a consideration that we need to think about because we don't want to implant patients and then have them just lose this technology.”

“We always talk to our patients as we're recruiting them about the fact that this is a permanent implant,” Putrino continued. “We make a commitment to them that they can always come to us for device related questions, even outside the scope of the clinical trial.”

But Putrino admits that even with the best intentions, companies simply cannot guarantee their customers of continued commercial success. “I don't really know how we safeguard against the complete failure of a company,” he said. “This is just one of the risks that people are going to take coming in. It's a complex issue and it's one I worry about because we're right here on the bleeding edge and it's unclear if we have good answers to this once the technology goes beyond clinical trials.”

Luckily, the FDA does. As one agency official explained to Engadget, “the FDA’s decisions are intended to be patient-centric with the health and safety of device users as our highest priority.” Should a company go under, file bankruptcy or otherwise be unable to provide the services it previously sold, in addition to potentially being ordered by the court to continue care for its existing patients, “the FDA may also take steps to protect patients in these circumstances. For example, the FDA may communicate to the public, recommendations for actions that health care providers and patients should take.”

The FDA official also notes that the evaluation process itself involves establishing whether an applicant “demonstrates reasonable assurance of safety and effectiveness of the device when used as intended in its environment of use for its expected life … FDA requirements apply to devices regardless of a firm’s decision to stop selling and distributing the device.”

The Synchron Switch BCI, for its part, is made from biologically inert materials that will eventually be reabsorbed into the body, “so even if Synchron disappeared tomorrow, the Switch BCI is designed to safely remain in the patient’s body indefinitely,” Oxley said. “The BCI runs on a software platform that is designed for stability and independent use, so patients can use the platform without our direct involvement.”

However, this approach “is not sufficient and that, given BCIs’ potential influence on individuals and society, the nature of what is safe and effective and the balance between risk and benefit require special consideration,” argued a 2021 op-ed in the AMA Journal of Ethics. “The line between therapy and enhancement for BCIs is difficult to draw precisely. Therapeutic devices function to correct or compensate for some disease state, thereby restoring one to ‘normality’ or the standard species-typical form.” But what, and more importantly who, gets to define normality? How far below the mean IQ can you get before forcibly raising your score through BCI implantation is deemed worthwhile to society?

The op-ed’s authors concede that “While BCIs raise multiple ethical concerns, such as how to define personhood, respect for autonomy, and adequacy of informed consent, not all ethical issues justifiably form the basis of government regulation.” The FDA’s job is to test devices for safety and efficacy, not equality, after all. As such the authors instead argue that, “a new committee or regulatory body with humanistic aims, including the concerns of both individuals and society, ought to be legislated at the federal level in order to assist in regulating the nature, scope, and use of these devices.”