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Brain-computer interface let’s paralysed people communicate

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Geneva: Scientists have developed a new non-invasive brain-computer interface that can decipher the thoughts of people who are unable to communicate – such as those living with completely locked-in syndrome – by measuring the changes in blood oxygen levels in the brain.

The technique could revolutionise the lives of those living with completely locked-in syndrome, according to a study by researchers from the Wyss Centre for Bio and Neuroengineering in Switzerland.

Counter to expectations, the participants in the study reported being “happy”, despite their extreme condition. Patients suffering from complete paralysis, but with preserved awareness, cognition, and eye movements and blinking are classified as having locked-in syndrome.


If eye movements are also lost, the condition is referred to as completely locked-in syndrome.

In the trial, patients with completely locked-in syndrome were able to respond “yes” or “no” to spoken questions, by thinking the answers.

A non-invasive brain-computer interface detected their responses by measuring changes in blood oxygen levels in the brain. The results overturn previous theories that postulate that people with completely locked-in syndrome lack the goal-directed thinking necessary to use a brain-computer interface and are, therefore, incapable of communication.

Extensive investigations were carried out in four patients with ALS (amyotrophic lateral sclerosis) – a progressive motor neuron disease that leads to complete destruction of the part of the nervous system responsible for movement.

The researchers asked personal questions with known answers and open questions that needed “yes” or “no” answers including: “Your husband’s name is Joachim?” and “Are you happy?”. They found the questions elicited correct responses in seventy per cent of the trials.

“The striking results overturn my own theory that people with completely locked-in syndrome are not capable of communication,” said Professor Niels Birbaumer, who led the study. “We found that all four patients 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,” he said.

The question “Are you happy?” resulted in a consistent “yes” response from the four people, repeated over weeks of questioning. “We were initially surprised at the positive responses when we questioned the four completely locked-in patients about their quality of life.

All four had accepted artificial ventilation in order to sustain their life, when breathing became impossible; thus, in a sense, they had already chosen to live,” Birbaumer added.        The research was published in the journal PLOS Biology.