The new report is posted in the New England Journal of Medicine and researchers in Britain and Belgium studied 54 patients in a state of unconsciousness.
Some 23 of the patients were in a so-called PVS state while the rest were listed as minimally conscious.
In a 2006 version of the study with the same patients, one patient showed her brain was responding when asked questions about imaging various activities such as playing tennis or remembering her home. Those got the right areas of the brain functioning when she thought about them.
In the new experiment, three other patients showed similar brain activity when asked similar questions.
In one man they asked him to think of two different things -- tennis and his home -- as a way to answer yes or no by showing the appropriate brain activity in response to questions.
“We asked basic biographical questions, like ‘Is your father’s name Thomas?’ and ‘Have you ever been to the United States?’" Adrian M. Owen, a neuroscientist at the Medical Research Council in Cambridge, England, who developed the method and was a co-author of the paper, told the New York Times. “We then checked whether the answers were correct. They were.”
The study had four vegetative and one minimally conscious patient able to respond to the yes or no questions using the brain activity.
Nicholas D. Schiff, an associate professor of neurology and neuroscience at Weill Cornell Medical College in New York City, told the newspaper that the study should "change the way we think about these patients."
“I think it’s going to have very broad implications," he said.
Dr. Joseph J. Fins, chief of the medical ethics division at Weill Cornell Medical College in New York, said the research opens up questions about whether the patients should be asked if they want to be killed via euthanasia -- but it has its problems.
“If you ask a patient whether he or she wants to live or die, and the answer is die, would you be convinced that that answer was sufficient?” he told the Times. “We don't know that. We know they're responding, but they may not understand the question. Their answer might be ‘Yes, but’ — and we haven't given them the opportunity to say the ‘but.’"
