Former Israeli prime minister Ariel Sharon, who has been in a coma since suffering a stroke in 2006, may have a degree of consciousness and be able to hear sounds or make out pictures, say scientists. The state-of-the-art fMRI brain scans that have allowed doctors to look inside the head of former Israeli prime minister show how advances in neuroscience are forcing a rethink of what it means to be in a long-term coma.
Neurologists who performed the tests say they hinted that Mr Sharon, who has been in a coma since suffering a stroke in 2006, may have a degree of consciousness and be able to hear sounds or make out pictures.
“It’s encouraging to find these signs because it opens up the possibility of some meaningful communication,” says Dr Paul Matthews, a professor of neurology at Imperial College London. Until recently, he says, it had been assumed that many comatose patients diagnosed as being in a “vegetative state” had no meaningful awareness of their surroundings.
Yet progress in the use of functional magnetic resonance imaging (fMRI) scanners — machines that measure brain activity by detecting changes in blood flow — and in reading the signals they give, has begun to change that view.
Compared with other “vegetative state” patients who have had similar tests and been described in scientific papers, Mr Sharon’s responses were very faint, says Dr Martin Monti, a cognitive psychologist from the University of California Los Angeles, who co-led the American-Israeli team that scanned Sharon’s brain.
There is little or no likelihood of a rapid recovery by Mr Sharon, who suffered his stroke weeks after leaving Likud to found a centrist group to pursue peace with the Palestinians. But with more tests and research to devise a way for him to signal whether he is processing external information, it is possible that he, like others, could one day respond to questions about his state of mind and whether he is in pain.
“If it turns out that these signals are more robust, then there’s no doubt that we could use things like brain-computer interfaces (to communicate),” Dr Monti says.
In the 84-year-old Mr Sharon’s case, evidence that he was able to perform the imagery tasks “was there but was not as strong as we have seen in other patients”, Dr Monti says. “We’re very cautious. There is a little evidence that he might have been doing some of the things we asked of him, but it was extremely weak and faint so it is difficult to interpret.”
If further tests on Mr Sharon were to detect a more robust response, scientists say the next step would be to investigate ways to make communication easier. One possibility being explored in some vegetative-state patients who show an ability to control brain processes is the use of electroencephalography (EEG) caps, which attach electrodes to the scalp and record electrical brain activity.
Research published in 2011 showed that scientists using these devices were able to communicate with people who had been considered to be in a vegetative state for more than a year. Because the caps are mobile, they allow communication to be more frequent, since putting a patient into an fMRI scanner every time doctors want to ask a question is invasive, disruptive and expensive.
“If you can put an EEG cap on somebody’s head, and the computer is trained to recognise different brain states, that’s like having a language,” Dr Monti says. “You could then imagine we could proceed from there.”
By Reuters Health and Science Correspondent Kate Kelland, source: globalpost.com
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