For the approximately hundreds of thousands of people living with quadriplegia around the world, interacting with the digital world is a daily challenge bordering on the impossible. Neuralink, the neurotechnology company founded by Elon Musk, is trying to address this problem with a brain-computer interface, the Link.
Just over 100 days ago, the first volunteer participant in Neuralink's PRIME study received the Link implant. What balance can we draw?
The digital divide for people with quadriplegia
As mentioned, losing motor function even in the upper limbs makes it difficult. Let me rephrase: impossible to interact with keyboards, touch screens and mice, severely limiting the ability of people with tetraplegia to participate in social, working and educational life online.
This digital divide can have profound consequences for quality of life. The inability to access online communication, information and entertainment tools can lead to social isolation, reduced employment opportunities and increased dependence on others to carry out daily tasks.
The Neuralink approach to tetraplegia: the Link brain-computer interface
The Link implant, an array of paper-thin electrodes surgically inserted into the brain, is designed to record neural activity and translate it into commands for digital devices, bypassing the need for physical inputs such as hand movement.
Neuralink's goal is to provide people with quadriplegia a means to interact more naturally and intuitively with digital technology. With the Link, participants can potentially type, browse the web, and control smart devices using just their thoughts. This could open up new possibilities for communication, creative expression, and independence for people with mobility disabilities.
The first implant in the PRIME study
Just over 100 days ago the first participant in Neuralink's PRIME study successfully received the Link implant. Noland Arbaugh, a 33-year-old patient volunteer, lost the use of his limbs following a spinal cord injury suffered in a 2019 car accident.
The surgery, performed at the Barrow Neurological Institute in Phoenix, Arizona, lasted about 3 hours and he experienced no complications. Noland was able to return home the next day and began the process of testing and calibrating the Link implant.
One-hundred of these days
Before the implant, Noland primarily used a tablet stylus held in his mouth to interact with digital devices. Maybe you can imagine (or maybe not) discomfort, muscle fatigue and bed sores with prolonged use.
You're giving me too much. It's like luxury overload, I haven't been able to do these things for 8 years and now I don't even know where to start giving my attention.
Noland Arbaugh
In the weeks following the surgery, Noland used the Link to control his laptop from various positions, including while lying in bed. He was able to play online games with friends. To surf the internet, live stream and use other applications on his MacBook, all while controlling a cursor with his mind. He even used the Link to play Mario Kart on a Nintendo Switch console, something he was unable to do since he suffers from quadriplegia.
Noland's routine
During weekdays, Noland participates in research sessions up to 8 hours a day. On weekends, personal and recreational use may exceed 10 hours per day. Recently, Noland has been using the device for a total of 69 hours in a single week: 35 hours of structured sessions and 34 hours of personal use.
If we consider 168 hours per week and subtract 56 hours of sleep, Noland used the Link for 69 of the remaining 112 hours. That's over 60% of the time, and makes it very clear that such tools could simply become indispensable for those suffering from tetraplegia.
Participation in research sessions allows Neuralink to evaluate the performance of the Link. The standard measure for cursor control speed and accuracy is the number of bits per second (BPS). During his very first research session, Noland quickly settled a new world record for human BCI cursor control, with 4,6 BPS. A record destined to be shattered quickly: a short time later reached 8,0 BPS, and now try to beat the scores of Neuralink engineers using a regular mouse (~10 BPS).
The problems encountered
It is clear that such complex experiments also present risks and inconveniences. In the weeks following surgery, some wires retracted from the brain, leading to a net decrease in the number of effective electrodes and a reduction in BPS.
In response to this change, Neuralink modified the recording algorithm to make it more sensitive to neural signals, improved techniques for translating these signals into cursor movements, and enhanced the user interface. These refinements have produced a rapid and sustained improvement in BPS, which has now surpassed Noland's initial performance.
Quadriplegia and neural implants: future perspectives
Neuralink's current work is focused on bringing the cursor control performance of people with tetraplegia to the same level as that of able-bodied people, and on expanding the functionality to include text entry.
In the future, the company plans to extend the Link's functionality into the physical world to enable control of robotic arms, wheelchairs and other technologies that can help increase the independence of people living with quadriplegia.
Conclusion
Neuralink's PRIME study represents an important step forward in improving the lives of people with quadriplegia in the digital age. Noland Arbaugh's experience demonstrates the potential of the Link implant to restore autonomy and independence to those living with mobility disabilities.
While there are still challenges to overcome, such as maintaining the effectiveness of the electrodes over time, the progress made by Neuralink in the first 100 days of the PRIME study is promising. As the technology continues to refine itself and expand its functionality, Link could open up new possibilities for people with quadriplegia, allowing them to interact more naturally and intuitively with the digital and physical world.
