How to make a paralyzed patient with brain implants talk

A young man in his thirties, completely paralyzed by Charcot’s disease, was able to express himself with electrodes implanted in his brain, according to a report published in the journal. good communication. This new step towards interfaces that can decipher our thoughts is a big step for medicine and technology.

Closed-in syndrome, when paralysis interferes with communication

I would like to listen to the Tool album loudly“, the Californian metal band finally writes the 34-year-old patient in German. We are 245 days after two electrodes were implanted in his brain, the only part of his body that is still under his control. Because the patient, quadriplegic, suffers from locked-in person syndrome (LIS), in which he hears and understands everything, but cannot move or speak.Different: he suffers from amyotrophic lateral sclerosis or Charcot’s disease.This is a neurodegenerative disease that the famous scientist also suffered from Stephen Hawking causes a progressive loss of motor control over his body.The fact is that, unlike most people with LIS, this patient cannot even blink once p Our yes and twice no is that the author of the famous book “The suit and the butterfly”, suffering from LIS after an accident, was able to write a book that was published in 1997.

In recent decades, many researchers have tested improved versions of this device using electrodes implanted directly into the brain. It has already been shown that these brain-computer interfaces allow “successful communication“with paralyzed people,” says Jonas Zimmermann, senior neuroscientist at the Wyss Center in Geneva and co-author of the new study. “But, to the best of our knowledge, our study was the first to communicate with a person who no longer has voluntary movements and for whom this interface is now the only means of communication..”

Three months to control the electrodes with the activity of your brain

In a room that was set up for him at home, it takes 105 days for a patient to learn to communicate with two electrodes implanted in areas of his brain responsible for motor control. Earlier, when he was still in control of his eyes, he mastered the previous version of the instrument, which was non-invasive. The interface then allowed him to communicate using horizontal eye movement. Without them covered by disease, he must find a way to activate the electrode. To help him, the scientists install a second “neural feedback” system that informs him with a beep whether he succeeded in activating the electrode or not. “The patient modulates his “discharge rate” (activation of neurons, ed.) until the sound he hears tells him he did it right“, – says researcher Ujwal Chaudhary, co-author of this work. How exactly is this done? It’s hard to say.”Can you tell me what do you think?asks third co-author Nils Bierbaumer. “Not me“. But Ujwal Chandhari hypothesizes. “We asked the patient what his strategy was, in response he wrote “EYE MOVEMENT”, which can be interpreted as the patient’s attempt to make eye movements to modulate the discharge rate, as before implantation.“.

One character per minute: communication at last

By trial and error, the patient manages to modulate the sound signal corresponding to the activation of his electrodes on the 86th day. Finally, on the 98th day, he manages to modulate the rate of neural discharge to achieve the goals set by the interface. On day 106, he successfully selects the letters when he speaks into his ear. If a certain threshold is exceeded and maintained for more than 250 milliseconds, the neural discharge signal captured by the electrodes is converted by the interface to “YES”, and below a certain threshold – as “NO”. When a patient manages to exceed 80% success during training exercises, the researchers allow him to make up his own sentences. At an average rate of one character per minute, he finally spoke. The first messages concern physical needs: “No shirt but socks“for the night” and “head is still straight“. Then less specific thoughts come. “Why can’t the system be left on. i find it goodhe hopes in German. The patient progresses in his learning and mastery of the system. “Guys it works finehe writes on the 247th day.

We have proven that communication is possible even for LCIS patients (complete confined space syndrome, approx. ed.), and that in these patients the thought does not disappear“, lists Ujwal Chandhari. “Many doctors and theorists of consciousness“assume that memory and consciousness exist”affectedparalysis, but the study shows that this is not true, the researcher continues. Finally, they report the possibility of “positive quality of life” even in this state, especially since their system worked in the patient’s home. “Our main achievement is to demonstrate that LCIS patients are not dead and unconscious, but happy and conscious, just like you and me.” adds Nils Bierbaumer.

Scientific and human success

Because before this success the satisfaction is of course scientific, but above all human. “We have provided a channel of communication for someone who otherwise would not be able to communicate.”, says Jonas Zimmermann enthusiastically. This brain-machine interface communication systemwill benefit the most severely paralyzed, people with brainstem stroke, amyotrophic lateral sclerosis, or high-level spinal cord injury“, suggests the researcher.

To help more patients, the researchers created a non-profit organization called ALS Voice. “The goal is to provide LIS and CLIS patients with a personalized means of communication through non-invasive and invasive brain-computer interface communication solutions.“, explains Ujwal Chaudhary. In addition, at the Wyss Center, where scientists work, a fully implantable and usable system for these interfaces is undergoing pre-clinical testing (in animals, in this case on sheep). This wireless system, called ABILITY “reduces the risk of infection and makes it easier to use”, says Jonas Zimmermann. It will detect and process signals from very specific or larger areas of the brain to directly decode speech in real time, combined with voice systems for more natural communication.

Making the brain speak directly: this prospect may have seemed dizzying until recently, but in 2022 the first results on a young patient make it almost tangible. In his room on day 253 he is talking to his 4 year old son. “willst du mit mir bald disney robin hood anschauen‘, he writes in character. In French, “Do you want to watch Disney Robin Hood with me?“.

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