Rather than building a device from scratch, Synchron and Paradromics take inspiration from previous medical devices. For example, Paradromics’ design is based on the Utah array, but with some important improvements. For example, it’s wireless and has 421 electrodes on the end of small wires that are placed in the brain tissue. All of these wires are much smaller than the Utah array shanks, Angle says.
Synchron’s device, on the other hand, is a hollow mesh tube similar to a heart stent. Rather than going directly to the brain, it is inserted into the jugular vein at the base of the neck and pushed up into the cortex. Synchron has so far implanted its device in 10 of her participants, one of whom has been using it for more than three years. (Arbaugh’s implant is still functioning after his 100 days). Banerjee said he has not yet seen any degradation in signal quality or performance.
Andrew Schwartz, a neurobiology professor at the University of Pittsburgh who develops brain-computer interfaces, also speculated that Neuralink’s design could push the implanted thread out of the brain.
To place the device, the dura mater, the outermost layer of the brain, must be opened. “Because multiple wires are inserted individually into the cortex, it can be difficult to suture the dura closed after implanting the wires,” he says. If this opening is left untreated, scar tissue may form around the opening and the threads may have become dislodged. Schwartz said the Utah array is designed so that the dura mater can be sutured shut after implantation.
Despite Neuralink’s setback, the company was able to livestream a demonstration of the device on March 20th, showing Arbaugh using the implant to play chess just by thinking.Arbaugh also used the device to play video games Mario Kart. “I can’t tell you how great it is to be able to do this,” he says. said in the video.
Neuralink said in a blog post that it compensated for the missing thread by changing its recording algorithm to increase its sensitivity to neural signals. It also says that it has improved the way these signals are translated into cursor movement, enhanced the user interface, and was able to improve the performance of the device with these changes.
When it comes to moving a cursor, Angle says the extra number of electrodes is less of a problem. However, for more complex tasks, such as converting text to speech, higher data rates become important.
Before getting the implant, Arbaugh used a mouth-held stylus known as a mouthstick to operate the tablet, which had to be held in place by a caregiver. Mouthsticks can only be used in an upright position and will interfere with normal speech. Prolonged use may cause discomfort, muscle fatigue, pressure sores, etc.
For Arbaugh, Neuralink’s devices are “luxury overload,” according to a company blog post. He still uses the implant, which allows him to “reconnect with the world” and do things on his own again without needing his family during the day and night.
“It’s good that patients can still use the device and are happy. At the end of the day, that’s a win,” says Angle. “But from our perspective, companies building brain-computer interfaces need to build devices that are robust and reliable over a multi-year period.”
There are expected to be setbacks on the road to commercializing brain-computer interfaces, and Neuralink’s unique approach to its device means it may face additional challenges along the way.
