Despite losing the ability to speak after a stroke more than 15 years ago, a man has been able to restore a type of speech thanks to a brain implant, researchers reported on Wednesday.
The University of California, San Francisco (UCSF) team developed a neuroprosthesis for a single patient, but they hope other paralyzed people may be able to communicate with it.
Man Can ‘Speak’ With A Computer Using A Brain Implant
According to Dr. Edward Chang at the research meeting, this is the first successful demonstration of decoding full words from the brain activity of a paralyzed individual who is unable to speak directly. The researcher at UCSF is a neurosurgeon. Chang said in a statement that choosing to utilize the brain’s natural speech machinery is an effective way to restore communication.
After having suffered a stroke at the age of 20, a man became paralyzed and was unable to speak. An electrode array was implanted in the speech control region of the brain. His head, neck, and limb movements have been severely limited since his injury, and he communicates using a baseball cap as a pointer that pokes letters on a screen.
He was found to be cognitively functional, according to the team’s report. While the device was tuned by translating electrical activity from the man’s brain using computer algorithms, he was asked to speak in a limited vocabulary. A computer screen was used to project these words.
UCSF filmed the device as the man used it. His computer screen prompts him, “Good morning.” A few seconds later, another text message appears on the screen, stating, “Hello.” In response to the question, “How are you today?” the patient replied, haltingly: “I’m fine.”
During the project, the team retrieved sentences in real-time, with a median word error rate of 25.6%, from a participant’s cortical activity. They found that during the 81-week study, 98% of the participant’s attempts to produce words were detected, and 47.1% of them were classified correctly using cortical signals that remained stable.
Over time the patient, who requested to remain anonymous, helped the team build a word bank of 50 words, including “yes,” “no,” “family,” “clean,” and “nurse.” These were expanded into full sentences like “I don’t feel thirsty.”
The electrode is not a permanent solution — it sits on top of the skull and needs to be replaced periodically. In addition, the researchers said, it cannot be attributed to a single experiment.
In previously published reports on brain-computer interfaces, decoding models often required daily adjustments before being deployed to users. The device, they mentioned, was more stable.
It is a significant technological advance for someone who is paralyzed and unable to talk naturally, proving that this technology may be able to give people with speech impairments a voice. It was he who worked on the study in Chang’s lab as a postdoctoral fellow.
It is only the beginning of the trial, Chang said. Here are the results of the first set of experiments done in this trial and the first participant who has been in the trial. In addition, she noted that it will be necessary to build more reliable systems and record higher amounts of brain information. On the algorithmic side, they need a system capable of translating these very complex signals from the brain into spoken words, and not just texts, but actually audible, oral speech.
They should extend the vocabulary so that it isn’t just limited to the 50 words that they started with, but something that is generic so that it can apply to all the words in English, for example. As well, he noted, they must ensure that the findings for this participant will be generalized to a larger population of patients.
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