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.