In 'vegetative state' patients, brain scanners show some alert minds
By Rob Stein
Washington Post Staff Writer
Thursday, February 4, 2010; A01
Many of the patients were labeled with the same grim diagnosis: "vegetative state." Their head injuries, teams of specialists had concluded, condemned them to a netherworld -- alive yet utterly devoid of any awareness of the world around them.
But an international team of scientists decided to try a bold experiment using the latest technology to peek inside the minds of 54 patients to see whether, in fact, they were conscious.
One by one, the men and women were placed inside advanced brain scanners as technicians gave them careful instructions: Imagine you are playing tennis. Imagine you are exploring your home, room by room. For most, the scanner showed nothing.
But, shockingly, for one, then another, and another, and yet two more, the scans flashed exactly like any healthy conscious person's would. These patients, the images clearly indicated, were living silently in their bodies, their minds apparently active. One man could even flawlessly answer detailed yes-or-no questions about his life before his trauma by activating different parts of his brain.
"It was incredible," said Adrian M. Owen, a neuroscientist at the Medical Research Council who led the groundbreaking research described in a paper published online Wednesday by the New England Journal of Medicine. "These are patients who are totally unable to perform functions with their bodies -- even blink an eye or move an eyebrow -- but yet are entirely conscious. It's quite distressing, really, to realize this."
Although Owen and other experts stressed that much more research is needed to confirm findings and refine the technology, they said the results could provide profound insight into human consciousness -- one of the most daunting scientific mysteries -- and lead to ways to better diagnose brain injuries and treat tens of thousands of patients. The technology also offers the tantalizing possibility of being able to finally communicate with some patients and ask, at the very least, whether they are in pain and need relief.
"This should change the way we think about these patients," said Nicholas D. Schiff, an associate professor of neurology and neuroscience at Weill Cornell Medical College in New York City. "I think it's going to have very broad implications."
Wider questions
The research inevitably raised questions about patients such as Terri Schiavo, a Florida woman in a persistent vegetative state whose family dispute over whether to discontinue her care ignited a national debate over the right-to-die issue that led to congressional intervention in 2005. Schiavo's brother, Bobby Schindler, said the new study highlights the limits of medicine to provide an accurate diagnosis.
"I wish this could have been used on my sister to see what could have been done to help her," Schindler said in a telephone interview.
But Owen, Schiff and other experts stressed that the research does not indicate that many patients in vegetative states are necessarily aware or have any hope of recovery. Many, like Schiavo, have suffered much greater danger to their brains for far longer than the patients in the study.
"In some cases, the damage to the brain is so severe that it is simply inconceivable they could produce any responses," Owen said.
As many as 20,000 Americans are in a vegetative state, meaning they are alive and awake but without any apparent sense of awareness, and 100,000 to 300,000 are in a related condition known as a minimally conscious state, in which they exhibit impaired or intermittent awareness. It is unclear what proportion of these patients would be affected by the study's findings.
A growing body of evidence in recent years has indicated that a significant proportion of such patients might have had their conditions misdiagnosed and have more awareness than had been thought.
Responsive minds
In 2006, Owen and his colleagues described the case of a young woman who had been thought to be in a vegetative state whose brain responded identically to a normal brain when placed inside a device known as a functional magnetic resonance imaging (fMRI) scanner and asked to imagine herself playing tennis or exploring her home. The case electrified neuroscientists. But it remained unclear whether her case was a fluke or represented a population of patients who were languishing with misdiagnoses.
Flooded with requests from desperate families to assess their loved ones, Owen and researchers at the University of Liege in Belgium started testing more patients. In the new report, the researchers describe the results from the first 54, including 23 who had a vegetative state diagnosed and 31 whose diagnosis was minimal consciousness.
Five, including the first woman, were able to repeatedly fire their brains in precisely the same way as hundreds of normal volunteers who were put in the fMRIs and asked to imagine themselves hitting a tennis ball, and wandering through their homes. Four of the five had received a vegetative state diagnosis, and one was thought to be only minimally conscious. Three showed signs of awareness during intensive standard bedside tests, but two did not.
The researchers then decided to see if they could use the approach to communicate with a patient. They told a 29-year-old man in Belgium to think about tennis if he wanted his answers to be yes and imagine touring his home for no. They then asked him yes-or-no questions about his life, such as whether his father's name was Thomas and whether he had brothers or sisters. He got every question right by thinking about tennis or being home.
"He could produce no communication with his body," Owen said. "But he could systematically and repeatedly change his brain activity to indicate yes or no with 100 percent accuracy."
Finding a way to communicate with brain-damaged patients has long been a goal of neuroscientists. It has also been the subject of literature and films, including the 2007 film "The Diving Bell and the Butterfly," which told the story of French editor Jean-Dominique Bauby. Bauby, paralyzed in a "locked-in syndrome" by a stroke, could communicate only by blinking his left eye.
But some urged caution, saying that the new technique raised a host of thorny questions.
"If a patient wanted to die, if they were asked, 'Do you want to die?,' could they explain themselves adequately?" said Joseph J. Fins, chief of the division of medical ethics at Weill Cornell Medical College. "If they say yes, what does that mean? If this person said yes but meant maybe, or it was 'sort of yes,' we may not be able to understand that sort of nuance. You have to be very careful."
washingtonpost.com |
