American researchers have just taken a huge step in treating aphasia. And by cultivating the brain, they were able to decode the signals from neurons and convert them into words.
“It’s a big step forward,” says Etienne de Villiers-Sedagne, a neurologist at the Neuro Hospital in Montreal, who was not involved in this US research but has done a lot of work in the field of language. “It would have been unimaginable to do something like this ten years ago.”
Drs De Villiers-Sedagne, who is in his late 40s, is almost convinced this type of treatment will become mainstream before he retires. “It is almost unlikely that it does not exist.”
Two approaches
in nature And on Wednesday, two teams from California showed their decoders reach speech speeds close to normal. “A person usually speaks at a rate of 150 to 200 words per minute,” Edward Chang of the University of California, San Francisco, said during a conference call on Monday. “We write 78 words per minute, with an error rate of 25%. Our patients tend to speak more slowly, to be more understandable.”
The other team, from Stanford University, achieved a speed of 60 words per minute and a similar error rate. Both teams reduced the error rate to less than 10% while reducing vocabulary, to less than 100 words. Both teams improved their algorithm’s performance by a factor of five compared to publications a few years ago.
There are two features of both experiments that strike Ds Villiers Sedan. “The patient does not need to train the algorithm for six months, as is the case in the first trials of its kind. The performance of the algorithm increases with the amount of microprocessors used. This means that there is room for improvement.”
The UCSD team used a microprocessor-filled plate that was inserted on the surface of the brain, under the scalp. They interacted with thousands of neurons associated with language. The Stanford team has implanted four chips that interact with a very small number of neurons inside the brain.
Broca’s area
Drs De Villiers-Sedagne notes that Stanford chips placed near an area of the brain associated with language, called Broca’s area, had less of an effect than those placed elsewhere. “It’s surprising,” he said.
These methods may work even if the patient has lost the ability to speak for several years. The Stanford University team worked with a patient who suffered a stroke fifteen years ago. However, these techniques may not help patients who have damaged the areas of the brain responsible for language, notes Dr.s Villiers Sedan.
Comment in nature The researchers welcome these developments, but note that noise from surrounding conversations, which the patient’s hearing picks up, could interfere with the algorithm. At a press conference, researchers from both teams confirmed that they had no concerns about this, because the areas of the brain responsible for hearing are different from those for speech.
The Stanford team also created an “avatar” that reproduced the facial expressions of a patient who had lost the ability to speak, from her wedding video.
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- 6000
- Number of people with aphasia each year in Quebec
Source: Quebec Aphasia
“Hardcore beer fanatic. Falls down a lot. Professional coffee fan. Music ninja.”
