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Stentrode

Meet the Stentrode: A Bluetooth Implant to Give You Mind Control Over Computers

By Simon Spichak, MSc | July 5th, 2022

Synchron is developing electronic devices that aims to help people with paralysis control their body, and the brain-computer interface (BCI) company has big ambitions for the future of BCI.

Dr. Tom Oxley has been obsessed with the brain since he was 13. “I studied medicine, because I just wanted to learn about the brain and help people with brain disease,” he explained. This fascination would lead him to the crossroads of cutting-edge science — and science fiction.

Today, Oxley is the CEO and founder of Synchron, a brain-computer interface (BCI) company that has begun enrolling patients into the first clinical trial of its kind. The brain-computer interface device, called the Stentrode, enables paralyzed people to control digital devices with their mind. 

Inserted through the jugular vein, the Stentrode is close enough to the brain to detect and relay signals out to a computer via Bluetooth technology. 

“People who are paralyzed can still think about moving their body. It’s the muscles that don’t work,” he said. “We essentially bypass the broken body by taking the information directly out of the brain to control devices that let them live independently.”

Oxley first read about this technology in a 2006 study published in Nature, detailing the first ever human implant of an invasive BCI. “I thought this was going to be a technology that can change humanity,” he told Being Patient.

In particular, Synchron is focused on helping people living with paralysis by enabling them to control electronic devices with their mind. If these trials are successful, Synchron may take aim at conditions like amyotrophic lateral sclerosis (ALS) and also allow for people to control prosthetic devices. 

An earlier safety trial of the Stentrode followed four patients with paralysis for a year after having the device implanted. No adverse events were reported. They were able to use the Stentrode unsupervised at home to do everything from sending text messages to online shopping. 

Synchron has received an investigational device exemption (IDE) from the Food and Drug Administration (FDA), allowing the company to assess the safety and to test the efficacy of the Stentrode before filing the data for approval. 

According to Oxley, this initial, IDE-backed patient enrollment for a permanently implanted BCI is an industry first, and “a major milestone for the entire field.” It has the potential to help with a range of other brain diseases and disorders in the future, he believes, and for now, the company is targeting the five million people in the U.S. currently living with paralysis.

Installing the brain-computer-interface

According to Oxley, eventually, this technology may allow people to control prosthetic limbs or even an exoskeleton. 

“We are focused on building a control language,” he said. “Once that has shown to be safe and effective, Bluetooth can then be used on any number of devices where input functions can control a system.”

It may also change a person’s perception of the divide between their body and their mind. “In a sense, [BCIs will] expand the brain’s ability to engage in different modes of function that wasn’t possible before,” Oxley said.

For Synchron and the other makers of brain-computer interfaces, the FDA’s safety standards are extremely strict. To help ensure they could meet these strict standards, the BCI team decided to look for devices that already exist and take inspiration where they could. 

“The FDA held us to lifetime testing, which is 80 years equivalent,” Oxley said. “The device has to stay in forever, and it stays as a part of the body.” This led them down the path of stents, another life-saving technology which is made from materials that can be safely inserted into blood vessels and left there permanently.

This approach also differentiates Synchron from other companies like Neuralink. Because the implant is placed in the jugular vein, the device itself doesn’t require invasive brain surgery for insertion, and it doesn’t need to directly sit on the brain to work. This lowers the risk of infection and immune reactions, Oxley said. 

“We are not causing an immune reaction inside the brain itself,” he explained. This also extends the lifespan of the Stentrode, allowing it to remain in the body for a person’s lifetime.

How does the Stentrode read brain activity?

When a neuronal cell fires, it causes a pulse of electrical activity. When many neuronal cells fire near the same area, it creates a local field potential. 

The Stentrode brain-computer interface is designed to translate brain signals from the inside of a blood vessel without the need for open-brain surgery.

“If you can detect the local field potential, that is from the population of neurons, that is associated with thinking, then you can predict when the thinking is happening,” Oxley told Being Patient. The Stentrode works by detecting where these local field potentials are coming from.

The device can build a “dictionary” of local field potentials for moving these muscles, Oxley said. “The part of the brain that controls your hand, is in the exact same part of the brain that controls my hand. It is quite predictable how the brain is functioning across the population.”

Harnessing the Stentrode for other applications

“The main focus for the company is to demonstrate that a BCI for the treatment of paralysis is safe and effective,” Oxley explained. “Once we’ve done that, we’re very excited about other applications.”

He added that there is potential for BCIs in treating a range of conditions including stroke, spinal cord injury, muscular dystrophy and multiple sclerosis. 

“Any person whose brain is still working, but the brain signals can’t connect to the muscles could potentially benefit from a BCI,” he said. 

He compares the adoption of BCIs to cochlear implants, which were originally tested for people severely affected by hearing loss, but are now used across a wide spectrum of people with hearing difficulties. “I think that’s what will happen with BCIs,” Oxley said. “It will start with the most severe people and it will move towards more mild to moderate people over time.”

How the Stentrode is leaving its mark

For Oxley, the most exciting part of working on the Stentrode isn’t the device itself. “The impact that the technology has had on our patients and their families and the patients with severe paralysis, is substantial,” he said of the few individuals who have so far undergone the experimental implant. Restoring even a small part of function and autonomy is “a very impactful and moving experience for the patient.”

According to Oxley, the most rewarding part is getting to work closely with individuals and their families, which gives him a first-hand look at how they use the technology. While Oxley acknowledged it will be a while before a BCI device like the Stentrode receives approval and widespread adoption, but once the industry reaches that milestone, this technology has the potential to improve millions of lives, he said. 

All photos courtesy of Synchron. 

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