Scientists have detected glimmers of awareness in some vegetative brain-injury patients and have even communicated with one of them - findings that push the boundaries of how to assess and care for such people.
The new research suggests that standard tests may overlook patients who have some consciousness, and that someday some kind of communication may be possible.
In the strongest example, a 22-year-old patient was able to answer yes-or-no questions by visualizing specific scenes the doctors asked him to imagine. The two visualizations sparked different brain activity viewed through a scanning machine.
"We were stunned when this happened," said Martin Monti of Medical Research Council Cognitive and Brain Sciences Unit in Cambridge, England. "This was a patient who was believed to be vegetative for five years."
Ever since a research paper four years ago showed apparent signs of awareness in a vegetative patient, one who was included in the new study, patients' families have been clamoring for brain scans, said Dr. James Bernat of Dartmouth Medical School, a spokesman for the American Academy of Neurology. A spokeswoman for a patient advocacy group said the organization will urge families to ask about the type of brain imaging used by the researchers.
But experts said more study is needed before the specialized brain scans could be used routinely. They emphasized that only a few tested patients showed evidence of awareness. And it was not clear what degree of consciousness and mental abilities the signs imply. They noted that the positive signals appeared only in people with traumatic brain injury, not in those whose brains had been deprived of oxygen, as can happen when the heart stops.
Terri Schiavo, the vegetative woman at the center of a national controversy before her feeding tube was removed and she was allowed to die in 2005, suffered oxygen deprivation.