By Rachael Levy
(Reuters) – Neuralink’s announcement last week that small wires in its first patient’s brain had become dislodged is a problem that Elon Musk’s company has known about for years, according to five people familiar with the matter.
Three of the sources said the company knew from animal tests it conducted last year before U.S. approval that the cables could be pulled back and the sensitive electrodes that decode brain signals could be eliminated with them. Neuralink thinks the risk is low enough that a redesign should not be considered, the sources added.
Neuralink is testing its implant to give paralyzed patients the ability to use digital devices by thinking alone; This is a possibility that could help people with spinal cord injuries.
The company said last week that the implant’s tiny wires, thinner than a human hair, were pulled from the patient’s brain in the first human trial, reducing the number of electrodes that can measure brain signals.
The signals are translated into actions, such as moving a mouse cursor on a computer screen. By making changes that included changing its algorithm to be more sensitive, the company said it was able to restore the implant’s ability to monitor the patient’s brain signals.
The sources declined to be named, citing confidentiality agreements they 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 application to begin human trials, one of the sources said.
The FDA declined to comment on whether it was aware of the issue or its possible significance. The agency told Reuters it will continue to monitor the safety of patients enrolled in Neuralink’s study.
If Neuralink continues testing without a redesign, it could run into difficulties if more wires are pulled and the fine-tuning of the algorithm proves insufficient, one of the sources said.
But redesigning topics has its own risks. Securing them to the brain, for example, could cause damage to brain tissue if the threads become dislodged or the company has to remove the device, two of the sources said.
The company tried to design the threads so they could be removed without problems so the implant could be updated over time as technology improved, current and former employees said.
In January, Neuralink implanted the device into the brain of its first patient, Noland Arbaugh, who was paralyzed from the shoulders down due to a 2016 diving accident.
In a blog update last week, Neuralink said that in the weeks after surgery, “some fibers in the brain retracted.” The post made no mention of Arbaugh’s adverse health effects and did not disclose how many of the device’s 64 threads were collecting or stopping collecting brain data.
So far, the device has allowed Arbaugh to play video games, browse the Internet and move the computer cursor on his laptop by thinking alone, according to the company’s blog posts and videos. Neuralink says Arbaugh broke the world record for speed at controlling the cursor with his thoughts alone shortly after surgery.
According to outside researchers and sources working at Neuralink and other medical device companies, it is common for medical device companies to troubleshoot different designs during animal trials and fix problems that arise during animal and clinical testing.
Experts who study brain implants say the problem of threads moving can be difficult to solve, in part because of the mechanism by which the brain moves inside the skull.
Neurologist Robert Gaunt from the University of Pittsburgh said that it was disappointing that the wires moved so soon after the surgery, but that it was not an unpredictable situation. “The days, weeks, months after an implant like this are probably the most vulnerable time,” he said.
PIG REMOVAL
The FDA initially rejected Neuralink’s application to begin human trials in 2022, citing safety concerns about the threads, Reuters exclusively reported last year.
Neuralink conducted additional animal testing to address these concerns, and the FDA gave the company approval for human testing last year.
The company found that a subset of pigs implanted with the device developed a type of inflammation in the brain called granuloma; This raised concerns among Neuralink researchers that the threads could be the cause, according to three sources familiar with the matter and recordings seen by Reuters.
Granulomas are an inflammatory tissue response that can form around a foreign body or infection.
In at least one case, a pig developed a severe case of the condition. Company records reviewed by Reuters show that the pig developed a fever and became worse after the surgery. Neuralink researchers did not realize the extent of the problem until they examined the pig’s brain after autopsy.
Sources familiar with the events said researchers at Neuralink were discussing how to fix the problem and launched a months-long investigation.
Ultimately, the company was unable to determine the cause of the granulomas but concluded that the device and its 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)