Brain scans could lead to consciousness 'gold standard'
By Sara Reardon IT CAN be nearly impossible to know what is happening in the mind of someone who has experienced a severe brain injury, but two new methods could offer some clues. They provide a better indication of consciousness and a potentially effective way to communicate with some people in a vegetative state. The way that a seemingly unconscious person behaves does not always reflect their mental state. Someone in a completely vegetative state may smile through reflex, while a perfectly alert person may be left unable to do so if a brain injury has affected their ability to move. Marcello Massimini at the University of Milan in Italy and his colleagues have developed a different way to assess mental state. They use an electromagnetic pulse to stimulate the brain, and then measure the response. The pulse acts like striking a bell, Massimini says, and causes neurons across the entire brain to “ring” in a specific wave pattern that can help identify whether someone is in a vegetative state, a minimally conscious state, or in the process of emerging from a coma (Science Translational Medicine, doi.org/nhr). “This is a big step forward,” says Joseph Giacino of Harvard Medical School in Boston, who was not involved in the study. He says the technique needs to be replicated with more patients, but it may provide a starting point for developing a much-needed gold standard for assessing consciousness. Such a tool could help identify which patients are sufficiently conscious to communicate. The method may provide a starting point for creating a gold standard for assessing consciousness Adrian Owen and Lorina Naci at the University of Western Ontario in London, Canada, say that such communication is possible. Building on work from 2010, they have developed a strategy to enable people in a vegetative state to answer questions with yes/no answers. After asking one such question, the researchers repeat the word “yes” a number of times, interspersing the yesses with distracting, random numbers. They then do the same with “no”. The patients had been told beforehand to indicate their answer by paying close attention to how many times their desired answer was repeated. The researchers scanned the participants’ brains during this exercise to help recognise when they were concentrating. The task was so effortful that it was easy for the participants to ignore the answer that they didn’t want to give, Naci says. They tested the technique on three people, two of whom were minimally conscious and one who had been in a persistent vegetative state for 12 years. All three patients were able to correctly answer questions about their names, for instance, and whether they were in a hospital (JAMA Neurology, doi.org/nhs). Naci suspects this relatively straightforward method may reveal consciousness in more brain-injured people than had been previously thought to have it, which raises questions about whether these patients could then have a say in their care. Caution would be required in such situations, says Naci, as a patient’s condition may have left them in poor emotional health. “If they are depressed or not emotionally healthy, we wouldn’t necessarily act on their wishes,” she says,