By Clare Wilson
When a person sustains a severe brain injury that leaves them unable to communicate, their families and doctors often have to make life-or-death decisions about their care for them. Now brain scanners are being tested in intensive care to see if mind-reading can enable some patients to have their say, New Scientist can reveal.
At the moment, doctors ask the families of people who have a poor prognosis and cannot communicate if they think their relative would want to continue life-sustaining treatments such as being on a ventilator. “Life would be so much easier if you could just ask the person,” says Adrian Owen at the University of Western Ontario in Canada.
Owen’s team previously developed a brain-scanning approach for a much smaller group of people – those in states between consciousness and being in a coma, for example those in a vegetative state. Such people show few signs of awareness and have to be fed through a tube.
Owen found that some of these people can direct their thoughts in response to instructions, which can be picked up on brain scans. If someone is asked to imagine playing tennis, for instance, the part of their brain involved in movement lights up in the scan.
This has let his and other teams ask those who are able to respond in this way yes/no questions, which can give people a say over their living conditions. About a fifth of people the technique is tried on can respond.
Owen is now using the same technique on people who are in intensive care in the first few days after sustaining a severe brain injury. In such circumstances, just over a quarter of people end up having their treatment withdrawn due to a poor prognosis.
For example, in some cases doctors may predict that if the person survives, they would be paralysed and unable to speak. “A decision will typically be made in the first 10 days about whether to go on or pull the plug,” says Owen.
His team has so far used brain scanning on about 20 such people in intensive care to try to communicate with them. Owen won’t yet reveal how many responded to questions, nor whether he asked them if they wanted to live or die.
But he says he has also made progress in developing a new brain imaging technique. The original method uses fMRI machines. To use them the person has to be taken to a separate room and put inside a scanner, and their tubes and equipment have to be changed to allow this to happen. “It’s really challenging and dangerous,” says Owen.
The new approach uses functional near-infrared spectroscopy, which can be done at the bedside and requires only a headset. Although the method visualises only a small part of the brain, this is enough to let someone answer a yes/no question by imagining playing tennis to give the answer “yes”.
In a paper published last week, Owen’s team showed this allowed volunteers without brain injury to accurately answer questions three-quarters of the time (Frontiers in Neuroscience, doi.org/dncs). The team has also used it successfully to speak to people with a condition that causes complete paralysis (see “Temporarily locked in”, below).
As well as conveying information about a person’s wishes, bedside mind-reading may also be useful for shedding light on their prognosis. Among people in a vegetative state, those who can respond to instructions in a brain scanner are more likely to recover, says Owen.
He believes the technique is more likely to lead to ventilator treatment being continued than stopped. “Negative findings are hard to interpret,” he says. “Positive findings are easier.”
“This is potentially exciting but I wouldn’t want people to get their hopes up because this might only be applicable to a very small group of people,” says Paul Dean of the UK’s Intensive Care Society.
If doctors are able to communicate with people in this way, they would have to be confident the patient had the legal mental capacity to make life or death decisions, says Jenny Kitzinger at Cardiff University, UK. “Have they understood the question, have they understood the diagnosis?”