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A study published by Monti and colleagues in 2010 in the New England Journal of Medicine (NEJM) was among the first to show how fMRI scans allowed doctors to detect awareness and communicate with patients in a long-term coma.
“The technology is still very new and we haven’t by any means optimised this kind of work yet,” said Steve Williams, of King’s College London’s centre for neuroimaging sciences.
“But if you do see something, it must give so much hope. And if you can get robust and consistent activation of the brain … then you can take it a lot further.”
The experiments use imagery tasks - such as asking a patient to imagine playing tennis or walking from room to room in their home. The fMRI scanner maps the distinctive activity of the brain when each task is performed.
The patient is then asked to equate one of the imagery tasks to the answer “yes” and another to the answer “no”, and apply them to simple yes-or-no questions.
These tests “give us a lot of information about how we can contact these patients and stimulate them”, said Alon Friedman, a neurological director at Israel’s Soroka Medical Centre in Beersheba, who worked with Monti on Sharon’s scans.
Of the 54 patients described in the NEJM study, all diagnosed as being in a vegetative or minimally conscious state, five were able to “wilfully modulate their brain activity”, the researchers said, and one was able to answer yes-or-no questions during the scan.
EEG CAPS TO AID COMMUNICATION?
In the 84-year-old 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”, Monti said.
“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 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,” Monti said. “You could then imagine we could proceed from there.”