Literature Review

Brain implant allows fully paralyzed patient to communicate


 

FROM NATURE COMMUNICATIONS

An experimental brain-computer interface has allowed a man with amyotrophic lateral sclerosis (ALS) who was unable to speak or move to communicate.

Using a commercially available implant and newly designed software, the patient, who was in the advanced stages of Lou Gehrig’s disease and unable to move his eyes, was able to interact with researchers and caregivers, requesting goulash, beer, and music from the band Tool, thanking the researchers who developed the technology and inviting his 4-year-old son to watch a Disney film.

The investigators note the study shows for the first time that communication is possible in patients in a completely locked-in state (CLIS) and offers hope for a better quality of life in this population.

“It should encourage them to live after artificial respiration and to ask for brain-computer interfaces before they become CLIS,” study investigator Niels Birbaumer, PhD, a professor emeritus of the University of Tübingen, Germany, said in an interview. The study was published online March 22 in Nature Communications.

Although the findings appear promising, they build on previous research that was the subject of a 2019 investigation by the largest grant-funding agency in Germany. This controversy prompted the institute that led the current research to appoint an independent expert to audit and monitor the new study.

Mechanism a ‘mystery’

Use of brain-computer interface (BCI) technology to allow ALS patients to communicate has increased in recent years. BCIs capture brain signals, transmit them to a computer, and convert them into a command that the computer carries out.

Previous research shows patients with ALS who retain eye movement and control have been able to use BCIs to communicate. However, until now, the technology has not worked as well in CLIS patients, who have full-body paralysis.

In 2019, German and Swiss researchers implanted two 64-microde arrays in the brain of a 34-year-old patient who was diagnosed with ALS in 2015.

The electrodes measure neuronal activity while an amplifier located on the outside of the patient’s skull amplifies the signals to a computer. Software created by the research team decodes the signals and translates them into commands.

Using an auditory feedback system, the patient was able to use his mind to modulate the pitch of a tone to either high (meaning “yes”) or low (meaning “no.”) Just how the brain does this is a mystery, Dr. Birbaumer said.

A speller program reads letters aloud, first in groups and then individually. When a group contained letters the patient needed to spell a word, he used auditory feedback to select the high-pitch tone.

Initially, the patient was able to correctly spell his name. Ultimately, he was able to form complete sentences. The patient correctly spelled words on 44 of the 107 days in that phase of the experiment, spelling an average of just one character per minute.

Still, the researchers note he was able to interact with his caretakers, family, and researchers, even offering input on changes to make the device more effective.

Controversial history

In 2017, Dr. Birbaumer and Ujwal Chaudhary, PhD, who is the lead author on this current study, published a study in PLOS Biology. That research analyzed a brain-monitoring technique that the scientists claimed enabled patients with ALS who were completely locked in to answer yes or no questions correctly.

Allegations from a whistleblower at the University of Tübingen, where Dr. Birbaumer was a senior professor and Dr. Chaudhary was a postdoctoral researcher, prompted an investigation by the Deutsche Forschungsgemeinschaft, or German Research Foundation (DFG).

The whistleblower claimed that the 2017 paper and a second study published in 2019 contained incomplete data and misrepresented the findings. The DFG investigation found evidence of scientific misconduct and required that Dr. Birbaumer return the grant he had received for the research. The agency also banned Dr. Birbaumer from applying for grants or serving as a grant reviewer for 5 years. Dr. Chaudhary was banned for 3 years. PLOS Biology later retracted the papers.

Both researchers have refuted the allegations and have reportedly sued the German Research Foundation.

“We have no information about the status of our lawsuit against the DFG; it’s still pending,” Dr. Birbaumer told this news organization. “I hope they investigate our present study because the study of 2017 they did not investigate carefully enough.”

Results ‘not stunningly good’

The controversial history prompted the Wyss Center, Geneva, which led this new study, to seek out at an independent BCI expert to audit and monitor the study.

Nick Ramsey, PhD, a professor of cognitive neuroscience at the Brain Center of the University Medical Center Utrecht, the Netherlands, agreed to take on the assignment in March 2020.

Dr. Ramsey has also conducted research on BCI in patients with ALS, but his work has not included patients in CLIS.

“I judged the study to be compliant with universal standards of scientific integrity,” Dr. Ramsey told this news organization. “I am confident that the data and results presented in the paper are valid and will withstand academic and medical scrutiny.”

Commenting on the new findings, Dr. Ramsey noted that the results of the study are “not stunningly good, as the user could only communicate during a limited number of days, and even then with considerable slowness,” Dr. Ramsey said. However, he added that the study does provide proof of principle that communication is possible in CLIS patients.

“The question remains whether a BCI implant continues to work well in these patients, as there are some indications that people in such a state may lose their mental capabilities within months or a few years as a result of the disease and can thus no longer generate a wish to communicate,” Dr. Ramsey said.

Responding to a query from this news organization, a spokesperson for Nature Communications declined to comment on the new study but said that journal editors are “are alert to controversies within each field and take care when considering submissions during the peer-review process.”

“We have rigorous policies to safeguard the integrity of the research we publish,” the spokesperson continued, “including to ensure that research has been conducted to a high ethical standard and is reported transparently.”

The research was funded by Wyss Center for Bio and Neuroengineering, Geneva and Deutsche Forschungsgemeinschaft. The authors have disclosed no relevant financial relationships. Dr. Ramsey received payment from the Wyss Center for his advisory role in this project.

A version of this article first appeared on Medscape.com.

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