By Rachael Levy
London: NeuralinkLast week’s revelation that small wires inside his first patient’s brain had moved out of position is a problem that elon musk company He has known this for years, according to five people familiar with the matter.
The company knew, thanks to animal tests it had conducted before its approval in the United States last year, that the cables could retract, removing the sensitive decoding electrodes with them. brain signalssaid three of the sources. Neuralink deemed the risk low enough that a redesign was not necessary, the sources added.
Neuralink is testing its implant to give paralyzed patients the ability to use digital devices while thinking on their own, a prospect that could help people with spinal cord injuries.
The company said last week that the implant’s tiny wires, which are thinner than a human hair, retracted from a patient’s brain in its first-in-human trial, resulting in fewer electrodes that could measure brain signals.
The signals are translated into actions, such as moving the mouse cursor on a computer screen. The company said it managed to restore the implant’s ability to monitor its patients’ brain signals through changes that included modifying its algorithm to make it more sensitive.
The sources declined to be identified, citing confidentiality agreements they had signed with the company. Neuralink and its executives did not respond to calls and emails seeking comment.
The U.S. Food and Drug Administration was aware of the potential problem with the cables because the company shared animal test results as part of its request to begin human trials, one of the people said.
The FDA declined to comment on whether it was aware of the problem or its potential significance. The agency told Reuters it would continue to monitor the safety of patients enrolled in the Neuralink study.
If Neuralink were to continue testing without a redesign, it could face challenges if more cables are disconnected and its algorithm tuning proves insufficient, one of the sources said.
But redesigning threads carries its own risks. Anchoring them in the brain, for example, could cause damage to brain tissue if the threads become detached or if the company needs to remove the device, two of the sources said.
The company has tried to design the threads for seamless removal, so the implant can be updated over time as technology improves, current and former employees say.
In January, Neuralink implanted the device into the brain of its first patient, Noland Arbaugh, who is paralyzed from the shoulders down due to a 2016 diving accident.
In the weeks after the surgery, “several threads retracted from the brain,” Neuralink said in a blog update last week. The post made no mention of adverse health effects on Arbaugh and did not reveal how many of the device’s 64 threads were disconnected or stopped collecting brain data.
So far, the device has allowed Arbaugh to play video games, browse the Internet and move a computer cursor on his laptop by thinking alone, according to company blog posts and videos. Neuralink says that shortly after surgery, Arbaugh broke the world record for the speed at which he can control a cursor by thought alone.
It is common for medical device companies to troubleshoot different designs during animal trials and for problems to arise during clinical and animal testing, according to outside researchers and sources who have worked at Neuralink and other medical device companies.
Specialists who have studied brain implants say the problem of moving strings can be difficult to solve, in part because of the mechanics of how the brain moves inside the skull.
Robert Gaunt, a neural engineer in it university of pittsburgh, described the movement of the wires so soon after surgery as disappointing, but said it is not unforeseen. “In the immediate days, weeks and months after an implant like this is probably the most vulnerable time,” she said.
PIG
In 2022, the FDA initially rejected Neuralink’s application to begin human trials and raised safety concerns about the threads, Reuters exclusively reported last year.
Neuralink conducted additional testing on animals to address those concerns, and last year the FDA granted the company approval to begin human testing.
The company found that a subset of pigs implanted with its device developed a type of inflammation in the brain called granulomasgenerating concern among Neuralink researchers that the threads could be the cause, according to three sources familiar with the matter and records seen by Reuters.
Granulomas are a inflammatory tissue response that may form around a foreign object or infection.
In at least one case, a pig developed a severe case of the disease. Company records reviewed by Reuters show the pig developed a fever and was vomiting after surgery. Neuralink researchers did not recognize the extent of the problem until they examined the pig’s brain post-mortem.
Within Neuralink, researchers discussed how to rectify the problem and began an investigation that lasted months, sources familiar with the events said.
In the end, the company could not determine the cause of the granulomas, but concluded that the device and attached threads were not to blame, one of the sources said.
(Reporting by Rachael Levy and Marisa Taylor in Washington; Editing by Greg Roumeliotis and Bill Berkrot)
