A patient unable to move a single muscle has communicated with doctors through a brain-computer interface (BCI). Although the process was slow, and the researchers responsible say further testing is required before widespread clinical use, the work could spark a revolution in care for people with locked-in syndrome.

Patients with motor neurone disease (MND) – also known as amyotrophic lateral sclerosis (ALS) – gradually lose control of the voluntary muscles. As the capacity to speak declines, some use computers that translate the movement of muscles they can still control into messages, most famously leading to Stephen Hawking's “voice”.

Further decline can lead to locked-in syndrome, where awareness remains, but voluntary muscle movements are, at best, limited to the eyes and eyelids. Locked-in syndrome can have other causes, such as in the case of Dominique Bauby, who dictated his memoir The Diving Bell and The Butterfly by blinking his left eyelid.

Difficult as this is – it took Bauby an average of two minutes per word – at least some communication is possible. Researchers are trying to help those with the most extreme locked-in syndromes, who cannot even move their eyes. In Nature Communications the Wyss Center's Dr Jonas Zimmermann and co-authors announce their success translating the brain waves of a completely locked-in MND patient to text.

Researchers implanted two microelectrode arrays in the motor cortex of a 34-year-old MND patient. “Before implantation, this person was unable to express his needs and wishes through non-invasive methods, including eye-tracking, visual categorization of eye-movements, or an eye movement based [Brain-Computer Interface]-system,” the paper notes.

We are very far from being able to “read the mind” of this patient or other patients in this state, whatever promoters of Neauralink may claim. However, the patient could modulate his brain waves to answer yes/no questions. This subsequently was extended to being able to spell out words in a method similar to Bauby's – the alphabet was read out, and the patient produced a detectable brainwave spike when the letter they wanted was reached.

To prove the patient was capable of using the speller as intended, he was asked to spell out his own name and that of his wife and son. On a slight majority of days, the patient was not able to produce intelligible words. However, when he was, he spelled out an average of 131 precious characters in the space of a two-hour session.

Although this doesn't allow for much complexity of communication, it was enough to ask for a head massage, request Tool be played “loud”, and tell his son he loved him. Perhaps most importantly, he was able to issue lasting instructions, such as the most comfortable position for his head to be positioned when visitors came.

Although the patient is a native German speaker, on days when he had English-speaking visitors he spelled to them in their native language.

“Successful communication has previously been demonstrated with BCIs in individuals with paralysis. But, to our knowledge, ours is the first study to achieve communication by someone who has no remaining voluntary movement and hence for whom the BCI is now the sole means of communication.” Zimmerman said in a statement. Having achieved this proof of concept, the potential for more advanced systems will be explored.

Although the authors say the safety, durability, and wider applicability of the implants need to be confirmed before they can be made available to everyone with locked-in syndrome, they also have hopes of developing faster and more reliable methods of communication. They also hope to develop systems that can be operated by patients' friends and family without the currently required trained oversight.