Brain implant allows incarcerated human to translate thoughts into written sentences

ALS (Amyotrophic Lateral Sclerosis) is devastatingly cruel. As neurons that control movement slowly die, you lose the ability to walk, speak, and breathe. Your mind remains sharp but you are completely locked in with no way of communicating with the outside world.

A 37-year-old man experienced this. Diagnosed at 30, he lost his ability to speak and walk in just 4 months. After two years he could no longer move his eyes – his only way of communicating with his wife and young son. Breathing on a ventilator and completely paralyzed, he was trapped in his mind.

Determined to break out of his physical prison, the man undertook a highly experimental procedure. Two arrays of microelectrodes have been surgically implanted in regions of the brain that control movement. A little over 100 days after the operation and after extensive training, the patient was able to use his mind to spell his thoughts in complete sentences.

His first request? Change his posture to make it more comfortable. his next? “I would love to hear Tool’s album [a band] loud,” then “Now have a beer.”

“People have really doubted whether this is even feasible,” said Dr. Mariska Vansteensel from Utrecht University Hospital, who was not involved in the study science.

When replicated, the system promises to bring communication back to hundreds of thousands of people locked in their heads, whether it’s from ALS, stroke, cancer or traumatic brain injury. The method is still far from being ready for clinical use. Aside from years of training, the procedure is highly tailored to each person, with a hefty bill of at least $500,000 in the first two years.

The field is also mired in controversy, as two of the study’s authors were embroiled in a scientific misconduct scandal over their previous work on incarcerated patients. Referring to the new work, brain implant expert Dr. Natalie Mrachacz-Kersting from the University of Fribourg, who wasn’t involved but is aware of her story: “I would say it’s a solid study.”

The patient doesn’t care at all. “First of all, I would like to thank Dr. Niels Birbaumer, the first author of the study,” he said in his mind. A year later, “My biggest wish is a new bed and that I can come to the barbecue with you tomorrow,” he told his family.

The long way there

Brain surgery is not the first choice.

After his diagnosis, the man devised a game plan familiar to every family battling ALS. In the center was an eye-tracking device that allowed him to spell out his thoughts. But as the muscles around his eyes began to fail, he was unable to fix his gaze, rendering the tracker useless. The family then developed their own pen-and-paper system to track simple thoughts based on his eye movements. It was rudimentary: any observable eye movement is taken as “yes”, otherwise they take “no”.

Realizing that he could soon lose all eye control, the patient began his journey to communicate solely through his brain’s electrical signals. With the advent of ever more powerful software and biocompatible brain implants, connecting the brain to computers—and bypassing neural damage—is exploding into a common, if still experimental, strategy to combat paralysis.

Using a non-invasive setup, electrodes were placed on the surface of his skull to record the broad electrical patterns of his brain. Because the skull scatters signals and introduces noise, the system also measured electrical signals through the eye as a separate data source. The study authors Birbaumer and his longtime colleague Dr. Ujwal Chaudhary’s system worked with a binary “yes” or “no”.

Within a year, communication failed again. Awaiting his fate of total fixation, the man – in agreement with his wife and sister – renounced his eyes entirely. Instead, they opted for brain implants to tap his neural signals directly.

Still a long way

In June 2018, just three years after his diagnosis, the man had two microarray electrodes implanted in his motor cortex. Each implant contained 64 channels to listen to his brain’s activity in order to decode it and communicate with the outside world.

It’s not a new idea. A 2016 study used brain implants — 16 electrodes in all — in a woman to control typing by imagining movements in her hand. Unlike the current patient, she was still able to blink her eyes, which made her case different. “We really don’t know if communication, even via brain signals, is still possible when all muscle control fails,” the study authors said.

Almost immediately they hit a wall. A day after implantation, when the patient could still move his eyes, the team asked him to rely on the family’s previous strategy of communicating “yes” or “no” while monitoring his brain signals. Unfortunately, the signals were far too weak. Asking the patient to imagine hand, tongue, or foot movements — all tricks from previous work — also failed to generate neural signals capable of deciphering his intentions.

Almost three frustrating months later, the team changed strategy. They used neurofeedback, a method that allows someone to modify their brain signals with real-time feedback about whether they’ve been successful. It sounds like academic-meets-new-age meditation and is somewhat unusual as a training paradigm. However, neurofeedback is being tested as a method of self-control of brain function for a variety of disorders, including anxiety, depression, insomnia, addiction, and others, with varying degrees of success.

Here, the team used auditory neurofeedback to better measure neural responses near the implanted electrodes. They first played a note and asked the man to try manipulating the note either higher or lower. Under the hood, the man’s neural impulses rose faster or slower depending on the pitch, providing a strong baseline.

Photo credit: Chaudhary et al., Nature

The strategy worked. The patient was able to change pitch on the first attempt. Within two weeks, he could only hit the note with concentration. These initial tests allowed the team to select very responsive neurons, and using the data they devised a simple strategy: by holding a tone high or low, it could first indicate “yes” or “no” and then individual letters.

A long way ahead

The training was tough. On each session day, the team began with 10-minute baseline recordings while the man rested.

“In this way, we can run our software program to determine the firing rate of different individual channels” to see which are optimal for neurofeedback, the authors explained. Overall, the man agreed with 80 percent of the feedback before moving on to the spelling sessions. Within the first three days he could spell his own name, his wife’s and his son’s.

But it’s still a grueling task: Even with months of training, he could communicate about one character per minute, or 131 characters per day. And those are just the understandable ones. Unfortunately there was no increase in speed even with training.

As tedious as it is, the man is able to reach out to his care team and family. A message told him to prop his head up higher when he had visitors. Another asked for no shirts but socks for the night.

“He even made suggestions to improve his spelling by spelling ‘turn on predictive text’,” the authors said about six months after implantation. Within a year he was telling the team, “Guys, it works so effortlessly” and asking his wife for a nice dinner of “goulash soup and sweet pea soup” in his feeding tube.

Tragically, time was not on his side. In the three years since its implantation, communication has slowed and become increasingly error-prone to the point of being completely incomprehensible.

Why this happened remains a mystery, but experts believe it’s likely due to scar tissue forming around the electrodes, which dampens signals from the brain. Although the authors did not report any inflammation or infection in the implant area, there is always a risk.

But as a trailblazer, the study outlines a fresh start for people who are incarcerated. It is a high reward with an extremely high responsibility: many patients may be at the end of their lives at this stage. How confident can we be in a technology that decodes their opinions on treatments and medical decisions? What happens when the brain implant misinterprets a thought that implies her caring? And in diseases with no cure, at what point do those mind-machine bridges become false hopes for loved ones as the brain slowly fades away?

All this does not bother the courageous patient for the time being. With the implant, he asked his four-year-old son to see Disney’s Robin Hood, or “Witches and Wizards” on Amazon. “I love my cool son,” he said with his wits.

Photo credit: Wyss Center

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