Neuralink’s disclosure last week that tiny wires inside the brain of its first patient had pulled out of position is an issue the Elon Musk company has known about for years, according to five people familiar with the matter.
Insiders familiar with the matter revealed that Neuralink had been aware, from pre-U.S. approval animal trials last year, that the delicate wires utilized in their implantation might retract, potentially dislodging the crucial electrodes responsible for decoding brain signals. Despite this knowledge, the company determined the risk to be sufficiently low to warrant a redesign.
Neuralink is currently engaged in trials aimed at empowering paralyzed individuals to operate digital devices through thought alone—a development with promising implications for those suffering from spinal cord injuries.
Recent reports indicate that in Neuralink's initial human trial, the implant's minute wires, thinner than a human hair, did indeed retract from the patient's brain, resulting in a reduction in the number of electrodes capable of capturing brain signals. However, the company managed to restore signal monitoring capability through adjustments, including algorithmic refinements.
Sources speaking on condition of anonymity, citing confidentiality agreements, disclosed these details. Despite attempts to reach out, Neuralink and its executives remained unresponsive to requests for comment.
It's noted that the U.S. Food and Drug Administration (FDA) was informed of the wire issue through the company's disclosure of animal testing results during the trial application process. However, the FDA declined to comment on the matter or its potential implications, stating it would continue monitoring patient safety throughout Neuralink's study.
Should Neuralink persist with its trials sans redesign, potential challenges may arise if further wire retractions occur and algorithmic tweaks prove insufficient, as cautioned by one source.
However, altering the wire design presents its own set of risks, such as the possibility of brain tissue damage if the threads dislodge or during device removal, as noted by sources familiar with the matter.
Neuralink has reportedly endeavored to design the wires to facilitate seamless removal, enabling future updates as technology advances, as per accounts from current and former employees.
The first recipient of the implant, Noland Arbaugh, paralyzed from the shoulders down due to a 2016 accident, experienced thread retractions in the weeks following surgery, as per Neuralink's recent blog update. Despite this, no adverse health effects were reported, and the exact number of affected threads was undisclosed.
Post-surgery, Arbaugh showcased remarkable abilities, including
playing video games, browsing the internet, and manipulating a computer cursor through thought alone, according to Neuralink's posts and videos. Allegedly, Arbaugh quickly surpassed the world record for cursor control speed via thoughts.
Industry experts note that issues encountered during animal and clinical testing are commonplace in medical device development. Addressing thread movement challenges remains complex, partly due to the brain's mechanical movements within the skull, as highlighted by Robert Gaunt, a neural engineer at the University of Pittsburgh. Gaunt stressed that experiencing wire movement shortly after implantation, while disappointing, is not unexpected, particularly in the initial stages post-surgery.
Pig heaving
In 2022, Reuters exclusively reported that the FDA initially declined Neuralink's application to initiate human trials, citing safety concerns regarding the threads.
Following this setback, Neuralink conducted further animal testing to address the FDA's apprehensions. Subsequently, last year, the FDA granted the company approval to proceed with human trials.
During the additional animal trials, Neuralink observed that a subset of implanted pigs developed a form of brain inflammation known as granulomas. This raised concerns among Neuralink's researchers, who speculated that the threads could be the catalyst for this reaction, as indicated by three sources familiar with the matter and corroborating records viewed by Reuters.
Granulomas represent an inflammatory response of tissue that can occur around foreign objects or in response to infection.
In one instance, a pig exhibited a severe manifestation of this condition. According to company records scrutinized by Reuters, the pig experienced post-surgery fever and distress. It wasn't until a post-mortem examination of the pig's brain that Neuralink's researchers fully grasped the severity of the issue.
Internally, Neuralink's research team engaged in deliberations on how best to address the problem, embarking on an investigation lasting several months, as detailed by sources acquainted with the proceedings.
Ultimately, despite efforts, Neuralink could not definitively pinpoint the cause of the granulomas. However, one source disclosed that the company concluded the device and its attached threads were not culpable.
