Even more significantly, one patient was able to answer yes and no questions using the researchers´ technique-indicating the potential for communication with people previously considered unresponsive.

Researchers at two centers, in England and Belgium, used functional magnetic resonance imaging (MRI) tests on 54 patients with severe brain injury. Of these patients, 31 were diagnosed as being in a minimally conscious state, meaning they showed intermittent signs of awareness such as laughing or crying. The other 23 were diagnosed as being in a vegetative state, meaning they were considered unresponsive and unaware of their surroundings.

The study is part of a growing body of work changing how people think about the vegetative state.

It´s possible some of the vegetative patients in the study had some consciousness but that brain injury may have left them deaf or incapable of responding, he said.

In an editorial accompanying the study, Allan H. Ropper, a neurologist at Brigham and Women´s Hospital, in Boston, pointed out that brain activity was found in only a small number of patients and that it doesn´t necessarily mean the patient has self-awareness or the ability to reflect. But, he continued, "the line between consciousness and unconsciousness will be blurred" as scientific understanding of the vegetative state deepens.

Dr. Owen said he and his team plan to continue refining functional MRI scans as a communication tool in hopes of eventually letting vegetative patients participate in their own care.