People Let a Startup Put a Brain Implant in Their Skull—for 15 Minutes

Jul 12, 2023

Emily Mullin

Elon Musk's Neuralink isn't the only company making progress on connecting people's brains to computers. In April and May, surgeons at West Virginia University placed thin strips of a cellophane-like material on the brains of three patients. Made by New York-based startup Precision Neuroscience, the thumbnail-sized strips are designed to conform to the surface of the brain without damaging its delicate tissue.

During the 15 minutes the devices were in place, the implants were able to read, record, and map electrical activity in part of the patients’ temporal lobes, which helps process sensory input. The patients were already in the hospital to have brain tumors removed, and doctors used Precision's devices alongside standard electrodes. Although just a small pilot study, it puts Precision one step closer to building a brain-computer interface, or BCI—a system that provides a direct communication link between the brain and an external device.

"This is the first time our technology has reached human patients," says Benjamin Rapoport, Precision's chief science officer and cofounder. Since the study posed a low risk to patients, the company didn't need permission from the Food and Drug Administration to carry it out. But it will need a green light from the agency to test it as part of a BCI. (Neuralink recently announced that it received FDA approval to test its BCI in people, but didn't release any details.)

Rapoport says that in the near term, Precision is planning to get its device cleared by the FDA for brain mapping and diagnostic purposes, as an alternative to the kinds of electrodes that are currently used to detect tumors and epileptic seizures. But the company's long-term goal is to help people who are paralyzed communicate and move. Rapoport says the company is in talks with the FDA but didn't say when its BCI trial would begin.

"We're on the cusp of a new generation of more meaningful interfaces that let us restore function or mobility for patients who are disabled," says Peter Konrad, chair of neurosurgery at West Virginia University's Rockefeller Neuroscience Institute, who was involved in the pilot study.

Precision is among a crop of contenders including Neuralink and Synchron that aim to commercialize devices that would allow people to control computers and prosthetic limbs using just their minds. Academic researchers have been working on these systems for decades, and a few dozen people around the world have been outfitted with them as part of studies. But now startups like Precision want to bring BCIs out of research labs and into people's everyday lives.

BCIs capture and decode brain signals, which are translated into commands and relayed to electronics that carry out certain actions, such as typing on a screen, controlling a computer cursor, or moving a robotic arm. Because neurons generate electrical signals, scientists can use conductive metal electrodes to record their activity. A device known as the Utah array is currently the mainstay in BCI research. Made of hard silicon, the array is a grid the size of Abraham Lincoln's face on a US penny. It has 100 tiny protruding needles coated with conductive metal that stick into the brain tissue and record the chatter of nearby neurons.

Lauren Goode

Lauren Goode

Julian Chokkattu

Will Knight

Because it penetrates the tissue, the Utah array can cause inflammation and scarring around the implantation site, which leads to a decline in signal quality over time. And signal quality is important because it affects how well the BCI performs. No one actually knows how long Utah arrays can last in the brain; so far the record is held by Nathan Copeland, whose device is now in its eighth year.

Placing a Utah array also requires surgeons to perform a craniotomy, making a small hole in the skull. It's a major procedure that can cause infection and bleeding, and recovering from one takes a month or longer. Understandably, many patients may be hesitant to undergo one, even if it means regaining a degree of communication or mobility.

Precision is trying to solve both issues with a device that has 1,024 electrodes but is ultrathin—about one-fifth the thickness of a human hair—and doesn't pierce the brain tissue. Instead of a craniotomy, it would be placed using a minimally invasive procedure that involves making a small slit in the skin and skull, then sliding the implant onto the brain's outermost layer, called the cortex. "The very idea of doing more damage to the brain or nervous system that's already damaged is pretty fraught," says Rapoport, who was also a cofounder of Neuralink. He thinks streamlining the procedure would make these systems much more attractive to patients.

Craig Mermel, the company's president and chief product officer, says the Precision array could be taken out as easily, too. As BCI technology improves, patients who get early brain chips may eventually want to upgrade to new ones. With Utah arrays, new devices usually can't be placed in the same area due to scar tissue.

With more than 1,000 electrodes, Mermel says, Precision's device will be able to provide a higher resolution of brain activity than current arrays. Precision's arrays are also designed to be modular. Several can be connected together to collect brain signals from a bigger area. For more precise or complex actions beyond stimulating basic body movements or triggering simple computer functions, "you’re going to want more coverage of brain regions," Mermel says.

Peter Brunner, an associate professor of neurosurgery and biomedical engineering at Washington University in St. Louis, says Precision's implant seems impressive, but there are still unknowns about how long it will last once implanted. Any device implanted in the body tends to degrade over time. "There's a tension between making things smaller and at the same time maintaining the robustness against the environment that these devices face in the human body," he says.

The brain shifts in the skull, and so can an implant, Brunner says. A surface array could potentially move around more than one that penetrates the brain. He says even a micrometer shift could change which group of neurons the device is recording from, which could affect how well the BCI operates.

Rapoport says all electrodes move around a little bit over time, but Precision's software, which decodes the neural signals, can accommodate those small shifts.

Lauren Goode

Lauren Goode

Julian Chokkattu

Will Knight

The company has yet to test the implant procedure on people, but Precision's scientists have tried it in miniature pigs and left the device in for about a month. They studied the animals’ brain tissue after the devices were removed to confirm that no damage was done, Rapoport says.

For the three human patients in the pilot study, the device caused no side effects or damage, according to Rapoport. It was able to collect detailed brain activity data from all three. Two patients were having tumors removed from brain regions responsible for language, and were awake during part of their procedures so that doctors could identify critical language areas in real time.

WVU will enroll up to two additional patients in the ongoing pilot study. Mount Sinai in New York City, Penn Medicine in Philadelphia, and Massachusetts General Hospital in Boston are expected to launch related studies soon.

An implant made by Synchron, another BCI startup, is already allowing a handful of people with severe paralysis to text, email, and surf the internet using only their thoughts. Implanting Synchron's device, which resembles a heart stent, also doesn't require removing a portion of the skull. It's inserted into the jugular vein at the base of the neck and threaded through until it's adjacent to the motor cortex, the brain's control center.

Neuralink's device will penetrate the brain tissue, but the company is developing a minimally invasive procedure using a sewing-machine-like robot to insert it into the brain. It's unclear whether Neuralink's initial human trial will involve this new procedure. Neuralink did not respond to an email inquiry from WIRED.

Academic labs are also testing novel concepts for less-invasive implants, including "neurograins" the size of salt that could be scattered across the brain's surface, or an injectable gel that would solidify into a conductive polymer once in the brain.

Jen French, who was paralyzed in a snowboarding accident in 1998 but can now walk with the assistance of a spinal cord implant, is hopeful about the next wave of BCIs. "Like so many people with chronic neurological conditions, we are told there's no cure," says French, executive director and founder of Neurotech Network, a nonprofit advocacy organization. Still, while the new generation of minimally invasive devices don't promise a cure, they could help people to regain meaningful function in their daily lives. "It's exciting to see all of these companies," French says, "because what that means for people with lived experience is that we're one step closer to being able to access the technology."