How Brain-Computer Interfaces Are Helping Stroke Survivors Speak Again Through the Power of Thought
On August 23, “Nature” magazine published a special article that caused a sensation around the world: American scientists allowed a woman who was severely paralyzed by a brain stem stroke to speak, but strangely, she spoke She didn’t say it herself, but through a substitute. She couldn’t say it herself because she had lost the ability to speak. But what she said was indeed what she wanted to say, and she used her own voice, and it perfectly matched the expression on her face. In other words, scientists have used AI technology to allow a person who has lost language ability to communicate smoothly with the outside world as before.
Brain-Computer Interface
Twenty years ago, Ann Johnson joined her husband in getting married. At the wedding banquet, she showed off her speech talent to the fullest and gave a toast for 15 minutes. She admitted that she hogged the microphone.
She was a teacher and volleyball coach back then. Being able to speak well was very important to her. However, fate sometimes takes away the things people cherish most. Just two years later, at the age of 30, she suffered a sudden brainstem stroke. With the efforts of medical staff, her life was saved, but her proud speaking ability left her forever. She was suddenly in a situation where she needed constant care.
Because she couldn’t move her hands, she couldn’t use sign language. For many years, she relied on a worn-out acrylic board to communicate with her family. There were 26 English letters posted on the board. Her husband followed her gaze to guess which one she was looking at. They just had a “conversation” one letter after another. The efficiency can be imagined.
With the development of technology, she added new equipment in the past few years, and the principle is not complicated: she puts a reflective sticker on her glasses, and she only needs to sit in the wheelchair and shake her head, and the camera can track the movement of the sticker. A “mouse” controlled by the head. This allows you to “click” on letters at will.
With this set of equipment, communication between her and her husband no longer requires guesswork and is much more accurate, but the efficiency is still not high. It takes 5 to 7 minutes to communicate two or three sentences.
This situation may come to an end this year.
A research team from the University of California, San Francisco and Berkeley has been working tirelessly for 10 years to develop a brain-computer interface called a smart brain, which communicates with external devices through brain electrical pulses, that is, directly converts signals in the brain. It can be converted into a computer signal, recognized and then synthesized into speech to help people who have lost language ability speak again and communicate normally. The team used brain-computer interface and AI technology to create a system tailored for Johnson. Now she can “speak” just by thinking in her head, which is very sci-fi.
Very sci-fi
. Her AI on the screen said: “Nice to meet you.” Her
husband replied: “I’m going to the store later.”
She just thought about it, and the system detected brain waves, and the AI said on her behalf: “Then when will you go home?” Not only words, but also expressions can be used. It’s like “Black Mirror”!
This was the first time in 20 years that Johnson had the feeling of having a real conversation with someone, and he couldn’t help but smile.
When introducing her previous machine to reporters, she was also interested in joking, smiling and typing: “I forgot how slow this machine is.” Her husband was also very happy, saying in an interview: “This is very important to me
. It was very heartwarming and inspiring for her. Of course, especially for her. She was very excited to hear her own voice again.”
Of course, achieving this sci-fi scene did not come without a price.
Johnson underwent a craniotomy last year to implant a paper-thin, credit card-sized electrode system in his cerebral cortex. A total of 253 electrodes cover her language and expression centers. If there was no such thing as a stroke, the electrical signals generated in these areas would control her tongue, lips, throat, and facial muscles to speak and make expressions. After a stroke, these functions are basically lost, but the electrical signals of the brain itself are still there, so scientists can use electrodes to read these signals, transmit them to a computer, and then use AI to analyze the meaning of the signals.
There is no need to worry about AI mastering “mind reading”, because scientists are not training it to understand words, but to let it find “phonemes”, which are the most basic units of words such as “aw”, “oh” and “eh”, so as to Guess the word.
In the words of Dr. Patil, an expert on the team, just like playing baseball, the batter does not “read the pitcher’s mind” but simply watches his movements and predicts the flight path of the ball based on experience.
The best batsman in the world cannot hit the ball 100% of the time, and similarly, AI cannot predict 100% accurately.
According to statistics from scientists, AI can guess about 76% of the words, but this is already quite impressive.
At this point, there is already text, and the final step is to let AI read the text, which is relatively common. It’s worth mentioning that they also used Johnson’s wedding video from 20 years ago to create her AI voice, which added a touch of personal touch.
Using this system, Johnson can “speak” 78 words per minute. The average conversational rate is about 160 words per minute. In comparison, the number 78 may not be very fast, but compared to the previous acrylic board and “head mouse”, this speed is already like a rocket.
In any case, the achievements of this technology are extremely amazing, and may be completely unimaginable to many people. Just by intercepting signals from the cerebral cortex, a person who has lost the ability to speak can be allowed to speak again. What a huge progress this is. The leader of the research team, Dr. Edward Zhang, chief of neurosurgery at the University of California, San Francisco, said that their ultimate goal is to allow patients to completely restore their natural way of communication and get rid of the brain-computer interface and allow wireless connections between the brain and the computer. .
This research provides a new hope for people who have lost their language ability, and also opens up a new possibility for the application of artificial intelligence in the medical field. It was published in “Nature” on August 23. The future is quite bright because technology is developing so fast.
Technology changes life
In July 2021, this system helped a man named Pancho.
Pancho was paralyzed in a car accident many years ago and lost most of his ability to speak. At this time, the team’s research had just started, and 128 electrodes were implanted in his brain. After a period of adaptation and training, Pancho’s speaking speed reached 15 to 18 words per minute, with an accuracy rate of nearly 75%.
Of course, this is not fast, so Pan Qiao still has to rely on a head mouse system when communicating with reporters… Even so, Pan Qiao is already very satisfied. He often couldn’t hold back his smile during experiments, making it impossible for the AI to guess his thoughts.
Who would have known that in just two years, the number of electrodes had doubled, the speaking speed had increased five times, and it had fully reached the level of daily use.
Perhaps in a few years, technology will help them fully resume communication at normal human speeds—a goal that’s not even that far off.
For people with stroke or ALS, this is undoubtedly life-changing gospel.
In 2018, a large bus accident occurred in Saskatchewan, where Johnson is located. She learned that the survivor suffered from PTSD (post-traumatic stress disorder) and needed psychological counseling. She decided to take a counseling course online.
At that time, she had not been exposed to this technology, so it was naturally difficult to realize this ideal. Now with the new system, hope is just around the corner: “I want to be a psychological counselor and use this technology to communicate with my clients.” “When I lost everything, I felt heartbroken. Later I told myself that I would never do it again. Don’t fall into that disappointing situation.” “Now, I feel like I have a mission again.”
This is probably the biggest meaning of “technology changes life”. I hope that Johnson can realize his dream of becoming a psychological counselor, and that increasingly advanced technology can actually help human beings live like this.
