WEDNESDAY, Nov. 9 (HealthDay News) -- An EEG, which measures brain activity, appears to be able to detect awareness in some patients thought to be in a permanent vegetative state, a new Canadian study finds.
Functional MRI (fMRI) is also able to show whether an unconscious patient has any awareness, but the high cost and limited availability of these devices make the test prohibitive for most patients, the researchers noted.
"We have been able to show that 20 percent of a group of 16 patients who, to the external world, appear to be unconscious are actually entirely conscious," said lead researcher Damian Cruse, a postdoctoral fellow at the Centre for Brain and Mind at the University of Western Ontario.
"When you think about the number of patients throughout the world who are considered to be in a vegetative state, 20 percent adds up to a large number of individuals who understand everything that is going on around them but are unable to show this," he said.
An EEG, also known as an electroencephalograph machine, can be brought to a patient's bedside and could potentially provide every patient with the opportunity to communicate with the outside world, Cruse added.
The report was published in the Nov. 10 online edition of The Lancet.
In this small study, 16 patients who had either traumatic brain injury or non-traumatic brain injury, and who had been diagnosed as being in a vegetative state, were tested with an EEG.
While undergoing the test, the researchers asked the patients to imagine movements of their right hand and toes.
In addition to the 16 patients in a vegetative state, the researchers also tested 12 healthy people.
Cruse's team found that three of the patients had appropriate responses on the EEG even though they appeared physically unresponsive. Two of these patients had suffered a traumatic brain injury and the other
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