For the first time, a bilingual person, who suffered a stroke more than ten years ago that caused him to lose the ability to speak, has been able to communicate in English and Spanish thanks to a brain implant.

The research, published in Nature Biomedical Engineering, helps to understand how the brain processes language and in the future could help people with speech problems to communicate.

The person participating in the study suffered a stroke when he was twenty years old that left him paralyzed and also caused anarthria, a disease that prevents him from articulating words and causes him to express himself with grunts.

When the patient was in his thirties, he contacted Edward Chang, Professor of Neurological Surgery at the Weill Institute for Neurosciences at the University of California in San Francisco, to investigate the brain damage caused by the stroke.

Chang’s team implanted electrodes in the patient’s brain in order to record his neural activity, which he translated into words that appeared on a display screen.

The patient is bilingual, his native language is Spanish, but after suffering the stroke he learned English.

Chang’s team, led by Alexander Silva, developed an Artificial Intelligence system to decipher the patient’s bilingual language, which consisted of training the AI ​​to formulate 200 words on a display screen. The patient’s efforts to articulate words created different neural patterns that were picked up by electrodes in his brain.

For more than 80 weeks, the patient’s brain was monitored to try to predict the exact words he wanted to use according to his brain pattern, in order to decode those words to form sentences.

The researchers applied their AI system, in both Spanish and English, to the sentences the patient was trying to say.

The system works as follows: to predict the first word of a sentence, the Spanish module chooses the word that best matches the brain pattern. The procedure is similar for English words.

From the first word the two modules try to make a sentence. To choose the second word they base not only on the activated neural pattern but also on the probability that that word follows the first in a sentence.

Finally, two sentences are produced, one in English and one in Spanish, of which the patient’s display screen only shows the one with a higher probability of being expressed. The modules distinguish between English and Spanish with an accuracy of 88%.

The results of this study contrast with previous studies that had shown that different languages ​​activated different areas of the brain. In this case, the researchers observed that much of the activity of the English and Spanish languages ​​took place in the same area.

Furthermore, the man’s neurological responses were quite similar to those of bilingual children even though he learned to speak English in his late twenties. From this study it is deduced that different languages ​​share some neurological characteristics, but a new study with a larger sample of people would have to be done to confirm this hypothesis.

Bioethical assessment

The use of implants in the brain of patients has been previously analyzed in our Observatory.

Examples of the potential of these interventions in the treatment of pathologies without effective therapies are: the possibility of walking correctly again for Parkinson’s patients and the ability to communicate or move for ALS or paralysis patients.

Therefore, research should be promoted to enable the use of electronic devices in the brain that can partially correct the serious limitations associated with certain degenerative diseases or the sequelae of severe trauma.

The bioethical difficulty arises when the intention of these techniques on the human brain is not to correct deficiencies that limit the affected patients but to provide capabilities that exceed the limits established by human nature.

Neuralink‘s intention to implant a chip in the brain that allows man to communicate with his smartphone through thought is an example of this type of application.

Enhancing memory or accessing computer databases with unlimited content through thought would mean providing the human brain with faculties that are far beyond from what brain physiology is capable of. The consequences of such experiments are unpredictable.

The term “enhancement” is used to describe these “improvement” interventions on the capacities inherent to our nature, so that its implementation would give rise to the “transhuman” first and the “posthuman” later.

The simple fact of artificially increasing certain capacities in brain functioning does not necessarily imply an improvement, since its consequences are still unpredictable.  Their long-term effects and their contribution to deepening inequalities between human beings are unknown.

The prudent application of these new therapeutic possibilities linked to the most sophisticated technology will help many patients and avoid excesses that can harm us all.

Julio Tudela and Ester Bosch

Bioethics Observatory – Institute of Life Sciences

Catholic University of Valencia

 

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