How do we know that patients with acute brain injuries who seem completely unresponsive really are? Some retain what doctors call “covert consciousness” – but which ones?
A new study published in the New England Journal of Medicine says that about 15% of such patients are responding to verbal commands in their brains in the days after their injury, even though there is no external sign of it.
Researchers recorded responses in specialized computer analysis of routine EEG recordings from the skull. These patients are “four times more likely to achieve partial independence over the next year with rehabilitation, compared to patients with no activity,” according to the New York Times.
The authors say that, if confirmed, the findings "could inform prognostication of acute brain injury and potentially provide a means of communication with patients who seem unresponsive on the basis of a conventional clinical examination."
The study looked at results from 104 patients in Columbia University’s neurological ICU who had head injuries from trauma, heart attacks, or bleeding.
“Somewhat to our surprise, we found that about 15% of patients who were not responding at all had this brain activation in response to the commands,” said Dr Jan Claassen, the lead author of the paper. “It suggests that there’s some remnant of consciousness there. However, we don’t know if the patients really understood what we were saying. We only know the brain reacted.”
“This is very big for the field,” Dr Nicholas Schiff, of Weill Cornell Medical College in New York, told the Times. “The understanding that, as the brain recovers, one in seven people could be conscious and aware, very much aware, of what’s being said about them, and that this applies every day, in every I.C.U. — it’s gigantic.”
Michael Cook is editor of BioEdge
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