NOS Nieuws•vandaag, 21:51
Two new brain-computer interfaces (BCIs) have succeeded in recognizing words in the brains of paralyzed people and then writing them out on a screen. In this way, the patients were able to communicate again at a speed of more than 60 words per minute, much faster than was possible until now.
The patients had access to a vocabulary of 125,000 words, with the computer displaying the correct word in 76 percent of the cases. With a more limited number of words, the accuracy even rose to over 90 percent.
“A major progress” and “a tipping point in the development of BCI technology that aims to restore communication in paralyzed people,” says neuroscientist Nick Ramsey of the brain center UMC Utrecht, who was not involved in the research. He emphasizes that communication is an essential human need, which some people are deprived of by neurological disorders.
Unintelligible due to stroke
In the first study, 253 electrodes were implanted in a patient whose speech had become unintelligible due to a stroke. A neural network analyzed her brain activity and converted it into sentences. After more than a week of training for just under two and a half hours, this resulted in a speed of 78 words per minute. For comparison: in an average conversation about 160 words pass by per minute.
The BCIs used convert the attempt to speak into words. “So thoughts are not converted into words, it is not mind reading. We look at the output station of the brain that controls the muscles. So that part still has to work,” says Ramsey.
“This is particularly interesting for people with ALS,” says Ramsey. “But people with a certain cerebral haemorrhage, with brain damage or who are partially paralyzed, can also use it. We have done research and in the Netherlands it would affect about 150 to 200 people. Worldwide, it concerns thousands of people.”
What are brain-computer interfaces?
A brain-computer interface (BCI) is a direct connection between the brain and a computer, where the transfer of signals can take place both wirelessly and wired. In the 1990s, experiments began connecting electrodes to nerve cells in the brains of paralyzed people.
In 2006, a large number of electrodes were used for the first time in the brain of a person with spinal cord damage to make movement possible again. The Dutchman Gert-Jan Oskam, who has a partial spinal cord injury, can partially walk again thanks to such a ‘digital bridge’, it was announced this year.
By placing such electrodes in the speech and movement centers in the brain, a very limited form of communication became possible again for some people. In most cases this involved controlling a robot arm, in a small number of cases it involved speech.
The technology used is not yet suitable for all paralyzed people. The patients in these studies could still mimic their speech; so there were still weak muscle movements. Scientists will have to find a way to train people who are completely paralyzed. These so-called locked-in patients can sometimes only communicate by moving their eyes.
Ferrari block without a car
In addition, wireless BCIs would be desirable for cosmetic reasons. At this point, the electrodes in the brain are still wired to the external computer. “These studies are a diamond in the rough,” concludes Ramsey. “I call it a Ferrari block without a car around it. That car has yet to come.” Several researchers worldwide are working on the development of this ‘car’, including Ramsey’s research group at UMC Utrecht.
Neuroscientist Nick Ramsey is a guest in the podcast on Friday Knowledge & Co to talk further about advancements in and the future of brain-computer interfaces.
2023-08-23 19:51:49
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