Completely paralyzed ALS patient learns to communicate again

The now 37-year-old man lost his speech as a result of the incurable nerve disease ALS (amyotrophic lateral sclerosis). In his right mind, he was trapped in his waking mind. Patients like him in the so-called “completely locked-in” stage no longer have any control over their eye movements, which is why other communication aids fail. Because one possibility is to record eye movements with cameras and to translate them into speech with software. Such a system was used by the famous physicist Stephen Hawking.

Now an international research team, co-led by Jonas Zimmermann from the Wyss Center of Bio‐ and Neuroengineering in Geneva, reports that the study participant learned to communicate with a so-called brain-computer interface (BCI) at sentence level. Invasive BCIs are small devices surgically implanted in the brain that use electrodes to record brain waves and convert them into control signals.

As the researchers write in the study published on Tuesday, the patient was able to express his needs after around a hundred days. For example, on day 251 he asked his son if he would like to watch the Disney film Robin Hood with him.

How hard neurons fire

To form words and sentences, the computer learns to assign “yes” and “no” to the firing rates of neurons in the brain’s motor cortex. By having a program read aloud letters, the study participant could say yes or no to using that letter. In this way he managed to form an average of one character per minute.

The case study provides evidence that willful communication is possible even for people who are completely mentally isolated, the researchers conclude.

However, Zimmermann dampens expectations: “It is a proof of concept with a single patient,” says the scientific director of the project in an interview with the Keystone-SDA news agency. The aim is to start a clinical study with more patients, for which new electrode implants are currently being developed that would grow in completely. The safety of such an implant is to be tested in pre-clinical animal studies.

The one used in the ALS study participant is connected to the computer with a plug and cable. “The plug poses a risk of infection because the wound has to remain open all the time,” says Zimmermann.

Hope for the not too distant future

In the not too distant future, brain-computer interfaces could help many ALS patients. This is the opinion of Anne-Lise Giraud Mamessier. The neuroscientist, who works at the University of Geneva and the Institut de l’Audition in Paris, was not involved in the study. Until then, however, a number of technological hurdles and those for better decoding of language intentions have to be overcome.

There is also a difficulty in generating enough successful proof of concept to convince patients to undergo brain surgery. She also emphasizes the importance of the electrodes. “They should be as safe as possible and have a very low probability of infection and brain damage,” says Giraud Mamessier.

fuss about previous study

In addition to Jonas Zimmermann, the German brain researchers Niels Birbaumer and Ujwal Chaudhary are among the study leaders. Birbaumer and Chaudhary already published a study in 2017, according to which four ALS patients learned to communicate – using a hood equipped with sensors. However, the study had significant shortcomings, and the journal “Plos Biology” finally withdrew it. The researchers were accused of massive scientific misconduct that has not yet been refuted.

The German Research Foundation (DFG) excluded Birbaumer for five years, and Chaudhary for three years, from any review activity and eligibility for applications. While Chaudhary accepted this, Birbaumer had filed a lawsuit against it in 2020. The legal process is about to be completed, and the DFG announced on request that it would be possible to provide information about the outcome shortly.

Very plausible results

According to publishers Springer Nature, which published the current work, the scientific reviewers of the studies are alert to controversies in each subject. They proceeded accordingly carefully. For reasons of confidentiality, however, one cannot comment on the editorial career of individual contributions, a spokeswoman wrote on request.

The neuroscientist Giraud Mamessier points out that other studies have shown that it is possible to decode binary decisions – i.e. “yes” and “no” statements. The “episode” that happened did not change her opinion of Birbaumer’s research, nor did her opinion of his “sincere desire to find solutions to improve the quality of life of locked-in patients”. She considers the results of the present study to be “very plausible”.


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