Neuralink keeps losing the thread on brain implant wiring

Elon Musk's neurotech startup's revelation that the tiny wires on its chip implants came loose from its first human patient's brain might not have been a first.

The Neuralink N1 implant has 64 threads, each thinner than a human hair, through which is distributed a total of 1,024 electrodes. It's not clear how many slipped out of quadriplegic patient Nolad Arbaugh's brain, but Neuralink revealed earlier this month that it was able to work around the problem.

Anonymous sources affiliated with Neuralink told Reuters that the thin wires loosening issue had allegedly manifested previously, during animal testing. The design flaw is possibly related to the extremely small size of the implant wires.

The Food and Drug Administration (FDA) was also aware of the alleged issue, according to the report, which stated that Neuralink reported it to the agency, though the FDA declined to confirm or deny it had knowledge of the issue.

The first public disclosure of the wiring issue came when Neuralink announced that the first human patient to get a brain chip implant had experienced the issue. The brain tech company only confirmed this last week, but said that the wires started coming out of the patient's brain just weeks after the initial surgery in January.

Neuralink did not disclose how many of the threads had come loose, only mentioning that the bitrate had been reduced as a result. It was able to mitigate the wiring issue with a more sensitive algorithm; however, this workaround could become less effective if more threads detach.

Despite the potential that this would make the implant non-functional, Neuralink reportedly decided the risk was low enough and that a redesign wasn't necessary. The reasoning was apparently that while the issue could impair functionality of the implant, the retraction of wires from the brain wasn't causing any damage. This stems from an intentional design choice as the wires are meant to be easily removable without injury.

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Had Neuralink gone with a wire design that anchored into the brain, two of the report's sources say, removing the wires either on purpose or accidentally could potentially damage brain tissue. Anchored wires would need to be permanently installed, a pretty big drawback for anyone who may want to upgrade or ditch their implants down the line.

However, another source said some kind of redesign might ultimately be necessary to progress with the medical trial.

Loose wires are allegedly not the only potential issue with Neuralink implants. During testing on pigs, it found that many subjects had developed a type of brain inflammation called granulomas, which normally occur in response to foreign objects or infections in the brain.

Although Neuralink reportedly determined internally that the granulomas were unrelated to the chip implant, it couldn't identify what caused it.

Concerns with testing Neuralink chips have persisted for years, and the FDA rejected requests to start performing trials on humans until a year ago. In 2022, the company's controversial animal testing came to a head when Neuralink was sued by an animal rights group and investigated by the US Department of Agriculture. ®