However, Morten Overgaard, head of the Cognitive Neuroscience Research Unit at Aarhus University in Denmark and author of an accompanying journal editorial, said there are two important problems with the study.
"First of all, almost all cognitive functions are found to work both consciously and unconsciously in healthy people. So, if people follow a command it's not an absolute clear indication that they are conscious of the instruction."
So, if an EEG were going to be a test to determine which patients will be treated and which patients won't be treated, the test is not strong enough to make that determination, Overgaard noted.
The second point has to do with how people are classified as being in a vegetative state. The current criteria have nothing to do with subjective experience patients might have. So these tests are too blunt to really identify which patients will benefit from treatment, he said.
"If you want to talk about whether these people are conscious, we need a new and different scale," Overgaard said. "This finding should not be used to just say some patients were misdiagnosed, but rather to challenge the categories we use now to talk about consciousness."
For more on coma, visit the U.S. National Library of Medicine.
SOURCES: Damian Cruse, Ph.D., postdoctoral fellow, Centre for Brain and Mind, University of Western Ontario, London, Canada; Jonathan A. Friedman, M.D., director, The Texas Brain and Spine Institute, Texas A&M Health Science Center College of Medicine, Bryan, Texas; Morten Overgaard, Ph.D., professor, head of Cognitive Neuroscience Research Unit, Aarhus University, Denmark; Jaime Levine, D.O., medical director, brain injury rehabilitation, NYU Langone Medical Center, New York City; Nov. 10, 2011, The Lancet, online
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