Brain Images of Woman in Vegetative State Hint at Awareness
Sophisticated brain-imaging techniques suggest that a young woman in a vegetative state five months after a traffic accident had some mental functioning, even though she was unable to physically respond to her environment, British researchers report today.
The woman’s brain showed mental activity virtually identical to that of healthy people when she was addressed in complex sentences and when told to imagine activities such as playing tennis, the physicians reported in the journal Science.
The findings challenge the standard diagnosis of a vegetative state, implying that some patients may have what Dr. Lionel Naccache of the French National Institute of Health and Medical Research called “a rich mental life” in an accompanying editorial.
“I was absolutely stunned” by the results, said Dr. Adrian M. Owen of the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, who led the study. “This showed that she is aware.”
That conclusion will inevitably bring new hope to people with loved ones in comas or vegetative states, along with demands for further testing -- a difficult proposition because most hospitals do not possess the expensive equipment required.
And Dr. Joseph J. Fins of Cornell University’s Weill Medical College in New York cautioned that because so little is known now, such brain scans might raise more questions than answers.
“This one picture may require a thousand words,” he said. “The technology is going to answer some questions, but it will create some difficult choices for families.”
Owen and his colleagues cautioned against drawing generalizations based on their report. “This is just one patient,” Owen said. “The result in one patient does not tell us whether any other patient will show similar results, or whether this result will have any bearing on her.”
Other experts were more critical.
“You don’t really know whether the patient is imagining a tennis game or simply responding to the word ‘tennis’ ” in much the same way that she would respond to a pinprick, Dr. Paul Matthews of Imperial College London told the journal Nature. “There is a lot that’s interesting about this research, but I think their result is overclaimed.”
The report immediately stirred memories of Terri Schiavo, the persistently vegetative Florida woman who became the center of a national controversy when her husband received permission over her parents’ objections to remove the feeding tube that was keeping her alive.
But experts noted that there were significant differences.
Accident victims, like the woman in the Science report, often have severed connections between brain cells, although the neurons themselves may remain intact. As many as half of those patients regain at least some consciousness within a year of the accident. After a year, however, few recover. Those who don’t are considered to be in a persistent vegetative state.
Patients who suffer heart attacks or strokes, like Schiavo, have a much more widespread death of brain cells because of lack of oxygen, sharply reducing their chances of recovering. The window of recovery for such patients is only about three months, Fins said.
A 1994 study of 700 patients found that none who had been in a persistent vegetative state for at least two years regained awareness. Schiavo had been bedridden for 15 years.
The 23-year-old woman in the current study was injured in July 2005. Within weeks, she opened her eyes and began sleep-wake cycles -- typical of patients in a vegetative state -- but she showed no sign of awareness or ability to respond to her environment.
A persistent vegetative state, in which the patient is awake but has no awareness of self or surroundings, is a state between coma and brain death. As many as 35,000 Americans are in such a state.
Owen and his colleagues studied her brain for five months using functional magnetic resonance imaging or fMRI. The technique highlights areas of the brain that receive increased blood flow when in use.
When researchers spoke sentences to her, a specific part of the brain showed activity -- the same part that lights up in healthy people hearing the same sentences. When the sentences included homonyms like “creek” and “creak,” additional parts became active. Random noises generated no response.
Finally, when they asked her to imagine playing tennis or wandering through her house, different areas of the brain were illuminated -- again identical to the areas responding in healthy volunteers.
Eleven months after the accident, the team reported, the woman began tracking a small mirror with her eyes, a sign that she might be transitioning to what is known as a minimally conscious state, often a sign of further recovery.
Fins speculated that she had already begun undergoing this transition when the fMRI tests were conducted and that those tests simply detected it earlier than her behavior indicated.
The researchers have refused to say what her current condition is.