Neuralink’s human trials volunteers ‘should have serious concerns,’ say medical experts

A medical ethics committee responded to Elon Musk's brain-interface startup issuing an open call for patients yesterday.
Elon Musk in suit

New reports cite horrific, deadly medical complications for Neuralink's test monkey subjects. Chesnot/Getty Images

On Tuesday, Elon Musk’s controversial brain-computer interface startup Neuralink announced it received an independent review board’s approval to begin a six-year-long human clinical trial. Neuralink’s application for quadriplegic volunteers, particularly those suffering from spinal column injuries and ALS, is now open. Less than a day later, however, a Wired investigation revealed grisly details surrounding the deaths of the monkeys used in Neuralink’s experiments–deaths that Elon Musk has denied were directly caused by the implants. 

Almost simultaneously a medical ethics organization focused on animal rights filed a complaint with the Securities and Exchange Commission urging SEC to investigate Neuralink for alleged “efforts to mislead investors about the development history and safety of the device.” In Thursday’s email to PopSci, the committee urged potential Neuralink volunteers to reconsider their applications.

[Related: Neuralink is searching for its first human test subjects]

“Patients should have serious concerns about the safety of Neuralink’s device,” wrote Ryan Merkley, director of research advocacy for the committee, which was founded in 1985 and has over 17,000 doctor members. “There are well-documented reports of company employees conducting rushed, sloppy experiments in monkeys and other animals.”

According to Merkley and Wired’s September 20 report, Neuralink experiments on as many as 12 macaque monkeys resulted in chronic infections, paralysis, brain swelling, and other adverse side effects, eventually requiring euthanasia. The FDA previously denied Neuralink’s requests to begin human clinical trials, citing concerns regarding the implant’s electrodes migrating within the brain, as well as perceived complications in removing the device without causing brain damage. FDA approval was granted in May of 2023.

[Related: Neuralink human brain-computer implant trials finally get FDA approval]

Elon Musk first acknowledged some Neuralink test monkeys died during clinical trials on September 10, but denied their deaths were due to the experimental brain-computer interface implants. He did not offer causes of death, but instead claimed all monkeys chosen for testing were “close to death already.”

Wired’s investigation—based on public records, as well as interviews with former Neuralink employees and others—offers darker and often horrific accounts of the complications allegedly suffered by a dozen rhesus macaque test subjects between 2017 and 2020. In addition to neurological, psychological, and physical issues stemming from the test implants, some implants reportedly malfunctioned purely due to the mechanical installation of titanium plates and bone screws. In these instances, the cranial openings allegedly often grew infected and were immensely painful to the animals, and some implants became so loose they could be easily dislodged.

In his email to PopSci, Merkley reiterated the FDA’s past concerns regarding the Neuralink prototypes’ potential electrode migrations and removal procedures, and urged Musk’s company to “shift to developing a noninvasive brain-computer interface, where other researchers have already made progress.”

As Wired also notes, if the SEC takes action, it would be at least the third federal investigation into Neuralink’s animal testing procedures. Reuters detailed “internal staff complaints” regarding “hack job” operations on the test pigs in December 2022; last February, the US Department of Transportation opened its own Neuralink investigation regarding allegations of the company unsafely transporting antibiotic-resistant pathogens via “unsafe packaging and movement of implants removed from the brains of monkeys.”

During a Neuralink presentation last year, Musk claimed the company’s animal testing was never “exploratory,” and only focused on fully informed decisions. Musk repeatedly emphasized test animals’ safety, stressing that Neuralink is “not cavalier about putting devices into animals.” At one point, he contended that a monkey shown in a video operating a computer keyboard via Neuralink implant “actually likes doing the demo, and is not strapped to the chair or anything.”

“We are extremely careful,” he reassured his investors and audience at the time.