Brain-sensing threads slip from gray matter in first human Neuralink trial

Oh well – next!

The first human to get a Neuralink implant may be doing fine now, but that's after a good deal of work to address post-surgical trouble that saw its performance significantly degrade.

Neuralink admitted the trouble with its first human patient, Noland Arbaugh, in a blog post this week. While mostly detailing the progress Arbaugh has made since his surgery in January, the Elon Musk-owned cybernetics firm also slipped in an admission of some trouble. 

"In the weeks following the surgery, a number of threads retracted from the brain, resulting in a net decrease in the number of effective electrodes. This led to a reduction in BPS [bits per second]," Neuralink said in the post. Bits per second is used as a measurement of Arbaugh's ability to control a cursor on a computer screen.

The Neuralink N1 implant has 64 threads, each thinner than a human hair, through which is distributed a total of 1024 electrodes. It's not clear how many slipped out of quadriplegic patient Arbaugh's brain, but Neuralink notes it was able to work around the problem. 

"We modified the recording algorithm to be more sensitive to neural population signals, improved the techniques to translate these signals into cursor movements, and enhanced the user interface," Neuralink said in its post. "These refinements produced a rapid and sustained improvement in BPS, that has now superseded Noland's initial performance."

What's that about retracted threads?

Neuralink says nothing about a reason for why an unspecified number of threads retracted themselves from Arbaugh's brain following surgery. We contacted the company to ascertain if it was willing to provide details, but didn't hear back. 

The Wall Street Journal, which said Neuralink only posted its blog about the slipped threads after the Journal started asking questions, did postulate a potential reason, however, suggesting it might have been down to air in Arbaugh's skull. 

Sources familiar with the surgery who spoke to the journal reportedly said that Arbaugh suffered from a condition known as pneumocephalus, in which air is trapped in the brain, following his implantation surgery.

Pneumocephalus is often asymptomatic and harmless, as is apparently the case for Arbaugh, but that reportedly didn't stop Neuralink from considering removing his implant entirely when threads begin to slip. 

Regardless of the problems Arbaugh has faced, Neuralink appears intent to carry on with its plan to implant more humans - the registry is still open and signups are available. The WSJ claims Neuralink wants to place 10 implants this year. 

Neuralink has previously faced a probe after allegations of animal welfare violations and another investigation over allegedly shoddy hazmat practices.

It'll remain to be seen whether Musk's biotech company will have more success with its second human prIME (precise robotically implanted brain-computer interface) candidate. Of course, it's always possible the R1 robot that performs the surgeries simply isn't very good at ensuring all the air is out of a patient's skull before closing it up. 

Either way, we'll have to wait and see how the second attempt goes. Who's up next? ®

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