Man recovers speech 18 years after stroke thanks to neurotransmitter

BarcelonaWhen she was 30 years old and in good health, a woman suffered a stroke that left her with tetraplegia and anarthria, which is the inability to speak. Since then, she only communicated with guttural sounds because she couldn't articulate words clearly. Now, 18 years later, she has regained speech thanks to a device that is capable of translating brain activity through a computer that pronounces what the patient is thinking. It is a neurotransmitter developed by researchers at the University of California and reported on in a study published this Monday in the journal Nature Neuroscience.

After suffering the brainstem stroke, the clinical evaluations performed by speech therapists were decisive: only 5% of the words she spoke were intelligible, and she was unable to make herself understood with sentences and open-ended responses. So, the patient began communicating with a whiteboard and a tablet. It was with that same whiteboard that she gave her consent to participate in the study that has finally allowed her to speak again 18 years later.

The researchers implanted more than 250 electrodes in her brain, specifically in the area that controls speech movements. To train the computer, they had the woman try to say simple sentences while recording her neural activity, even though she couldn't speak. Little by little, the device became better at interpreting the patient's thoughts, and she began to try more complex sentences that hadn't been previously indicated.

Custom voice

The researchers finally achieved that the device could produce fluent and intelligible speech with a wide vocabulary by connecting the brain to the computer. In fact, the authors claim it can say words the participant hadn't used during training and pronounce them correctly. Furthermore, they took recordings of the patient's voice from 18 years ago and customized the device so that it speaks just as she did before the injury.

Although they acknowledge that further research with a wider range of participants is needed, the authors believe this technology could help patients with anarthria speak "more naturally and perfectly in real time and improve their quality of life." They also emphasize that these findings represent "a new paradigm in neurospinal prosthetics" to restore oral communication in people with paralysis.