When the researchers asked the woman to imagine she was playing tennis, her brain scanner lit up in virtually the same places as the brains of healthy volunteers asked to do the same thing. (Image: iStockphoto)
Brain scans of a woman who has been in a vegetative state for five months show her imagining playing tennis and responding to commands, researchers report.
They say their study, published today in the journal Scienceshows that the woman was conscious despite her comatose state, although several experts disagree.
The researchers stress that the study is unlikely to shed light on issues such as the case of Terri Schiavo, a Florida woman who spent 15 years in a persistent vegetative state and was allowed to die in March 2005 after a lengthy court battle.
Dr Adrian Owen, neuroscientist at University of Cambridge and colleagues from the United Kingdom and Belgium used functional magnetic resonance imaging, or fMRI, to observe the woman’s brain in action.
The 23-year-old woman, injured in a car accident, was unconscious, unable to communicate and met clinical criteria for a vegetative state, according to researchers.
They examined his brain function by listening to sentences such as “There was milk and sugar in his coffee.” The brain scan lit up very similarly to that seen in healthy volunteers, Owen’s team found.
The researchers then asked the woman to imagine certain actions.
“One task consisted of imagining playing a game of tennis and the other was imagining visiting all the rooms of one’s house, starting with the front door,” the researchers write.
His scanner lit up in virtually the same places as the brains of healthy volunteers asked to do the same thing.
“These results confirm that… this patient retained the ability to understand and respond to voice commands through her brain activity, rather than through speech or movement,” the researchers write.
She also clearly intended to cooperate, which “confirmed beyond doubt that she was aware of herself and her surroundings,” they write.
“This is unlikely to be the case for all vegetative patients,” Owen’s team warns in their report.
Experts note that the woman suffered relatively little brain damage and say traumatic brain injuries often heal better than injuries caused by a stroke or heart attack like the one Schiavo suffered.
Schiavo had also been in this state for much longer than the Brit, leading to severe brain deterioration.
Dr. Ross Zafonte, brain rehabilitation expert at University of Pittsburgh Medical Schoolsays the study shows a unique way to assess brain function using analytics.
“They raise a whole question about consciousness and how we use the term,” Zafonte says.
“Is this just a rare bird? Will we see this more often?”
Other brain experts are skeptical.
“If this patient is truly conscious, why would she not be able to engage in intentional and overt motor acts, given that she has not suffered functional or structural damage to the motor pathways?” asks Dr Lionel Naccache from INSERM research institute in a commentary published with the report.
He says the patient apparently has “a rich mental life, including auditory language processing and the ability to perform mental imagery tasks.”
The study highlights the need to develop better scanners to assess a patient’s brain condition, says Naccache.
Dr Paul Matthews, neuroscientist at Imperial College London And University of Oxfordsays the study does not demonstrate consciousness.
“Response to stimuli, even complex linguistic stimuli, does not provide evidence of a ‘decision’ to respond. The withdrawal of a painful, unexpected pinprick does not represent a ‘decision’ to respond,” he says.
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