© AFP Photo DDP / Nigel Treblin Germany out
It has been assumed that about one in five patients who appear to be entirely vegetative may actually be conscious, but researchers had not been able to prove that was the case until recently.
A research team at the University of Western Ontario, led by post-doctoral researcher Lorina Nacia, has developed a sensitive method to test whether any neural activity is taking place during a film sequence. The study is described in a report approved in August.
The researchers needed a clip short in length, 7-8 minutes, for the duration that a person can be placed in an MRI. They discovered that Alfred Hitchcock's short "Bang! You're Dead" fit the bill. It has a story sequence with a beginning, a middle, and an end, and is about a child who carries a loaded revolver around town.
Twelve healthy volunteers and two behaviorally unresponsive, brain-injured people with unknown levels of consciousness were included in the study.
At the highly suspenseful moment of the movie, the healthy volunteers showed synchronized neural activity in high-level cognitive functions - areas that monitor human's surroundings.
Of the two people in vegetative states, the film evoked no activity in the 20-year-old woman - although she did show brain activity in the sensory areas, according to Nature.
In the other patient, however, researchers saw brain activity resembling that of a healthy participant. The man has been unresponsive for some 16 years, since he was a teenager.
"It was actually indistinguishable from a healthy participant watching the movie," study co-author Adrian Owen of Western University, who led the team, told Nature.
Nacia said the new results may reveal that more than one in five of patients in vegetative states are in fact conscious.
"What we are really trying to achieve here is to find ways of identifying in patients who are actually conscious, despite appearing non-responsive in a vegetative state, in order that we can allow them to play some role in what happens to them, therapeutic choices, rehabilitation," said Owen on the YouTube announcement. "Even improving their quality of life in really small ways like asking them what they would like to watch on television. So this is one step towards that goal of identifying these patients and finding a way of communicating with them."
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