When a brain injury leaves a person unresponsive and unable to communicate, doctors and nurses must provide care without input from their patient, and families agonize over whether their loved one might still have--or someday recover--a flicker of consciousness. A new study provides hope that technology might open a line of communication with some such patients. Researchers report that a man with a severe brain injury can, by controlling his thoughts, influence scans of his brain activity and thereby answer simple questions.
The work builds on a 2006 Science paper by Adrian Owen, a neuroscientist at the Medical Research Council Cognition and Brain Sciences Unit in Cambridge, U.K., and colleagues. Using functional magnetic resonance imaging (fMRI), they tested a young woman diagnosed as being in a vegetative state following a car accident. Although she was unresponsive and apparently unaware of her surroundings, she exhibited distinct patterns of brain activity when asked to imagine herself playing tennis or walking through the rooms of her house. As in healthy volunteers, imagining tennis activated motor planning regions in the woman's brain, whereas picturing her house activated a brain region involved in recognizing familiar scenes.
In the new study, published today in the New England Journal of Medicine, Owen and several colleagues used similar methods to examine 53 additional people who were in a vegetative state or in the slightly less severe minimally conscious state, in which patients show occasional flashes of responsiveness. In four of these patients, the researchers found distinct patterns of brain activity during the tennis versus house imagination task, hinting at some level of awareness that could not be detected by observing their behavior, says co-author Steven Laureys, a neurologist at the University of Liège in Belgium.
In one patient, a 22-year-old man who'd been in a vegetative state for 5 years, the researchers took an additional step, asking him to answer six questions by imagining tennis to indicate "yes" or picturing his house to indicate "no." The questions all involved basic autobiographical details, such as the name of his father or whether he had any brothers or sisters. In a group of 16 healthy volunteers, this method worked 100% of the time, the researchers report. The vegetative state patient answered the first five questions correctly. The final question elicited virtually no activity in the brain regions of interest, and the researchers speculate that the man may have fallen asleep or simply decided not to answer.
"This is a major step forward," says Nicholas Schiff, a neurologist at Weill Cornell Medical College in New York City. The paper is important because it shows that the Science report was not an isolated case and that technology can be used to establish communication with some patients who show no outward signs of consciousness, Schiff says.
Laureys cautions, however, that the fMRI method is not ready for widespread use in hospitals. He and collaborators are now trying to adapt the imagination task to work with electroencephalography, a relatively low-tech alternative to fMRI that's less expensive and easier to operate. "Our mission now is to translate this to clinical reality," Laureys says.
If such methods do become more widely available, they are sure to raise a host of sticky clinical and ethical questions, says James Bernat, a neurologist at Dartmouth Medical School in Hanover, New Hampshire. For example, doctors would want to involve patients in decisions about their care. But, Bernat asks, would a system that allows only yes or no answers make a physician "confident that all the nuances have been dealt with ... that they're dealing with a rational wish of the person that has been thoughtfully considered?"