Complete Locked-In State (CLIS) is probably the most terrifying of medical conditions to contemplate. In CLIS, patients with fully functional brains are trapped in bodies that they have no control over whatsoever, and have no means to contact the outside world despite being fully aware of what's happening around them. Now a team led by neuroscientist Niels Birbaumer at the Wyss Center for Bio and Neuroengineering in Geneva has found a way to connect the brains of CLIS patients to a computer that allows them to answer simple yes/no questions.

According to Professor Birbaumer, no one knows how many people suffer from CLIS. Those in a locked-in state are utterly dependent on others to fulfill even the simplest of needs. Worse, it is a condition where the patient and another person can be in the same room, yet the complete lack of ability to communicate even by eye movements means that they might as well be on separate planets. In fact, the cut off is so complete that until recently doctors weren't even sure CLIS sufferers could communicate at all if the means were available.

For the Wyss study, four CLIS patients suffering from amyotrophic lateral sclerosis were connected to the computer using a non-invasive brain-computer interface (BCI) that measured their responses to questions by monitoring changes in blood oxygen levels and electrical activity in the brain.

In an interview with the BBC World Service, Professor Birbaumer explained that the patients were read hundreds of questions repeatedly that had definite and known yes/no answers, like "Is London the capital of Britain?" or "Is Paris the capital of Britain?"

Using a computer to analyze that output, the Wyss team were eventually able to deduce when a patient was signaling yes or no with an accuracy of seven out of ten. After that, they were given questions that had unknown answers, such as "Are you happy?" According to the team, the consistent "yes" answers to that question went counter to expectations. Birbaumer attributes this attitude to the survival of the patients, who he believes have short lifespans if they do not cultivate a positive mindset.

Professor Birbaumer inspecting the interface(Credit: Wyss Center)

"The striking results overturn my own theory that people with complete locked-in syndrome are not capable of communication," says Birbaumer. "We found that all four people we tested were able to answer the personal questions we asked them, using their thoughts alone. If we can replicate this study in more patients I believe we could restore useful communication in completely locked-in states for people with motor neuron diseases.

"We were initially surprised at the positive responses when we questioned the four completely locked-in participants about their quality of life. All four had accepted artificial ventilation in order to sustain their life when breathing became impossible so, in a sense, they had already chosen to live. What we observed was as long as they received satisfactory care at home, they found their quality of life acceptable. It is for this reason, if we could make this technique widely clinically available, it would have a huge impact on the day-to-day life of people with complete locked-in syndrome."

Though BCI systems have been used to help victims of paralysis and stroke, this has been the first time direct communication with a CLIS patient has been achieved. The hope is that the technology will not only help sufferers of CLIS, but will also have wider applications in monitoring and alleviating other neurological conditions.

The research was published in PLOS Biology.

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