They compared the patients' brain responses to those of 12 healthy volunteers.
Three of the 16 people in a vegetative state were able to reliably activate the same parts of their brain that become active when healthy individuals are given the same command.
Owen said the three patients ranged in age from 20 to 45 years and had different types of injuries.
"One of the patients had been in a vegetative state for almost two years and yet he was able to understand what we were trying to do and show he was aware," despite looking completely vegetative, Owen told a news briefing.
Curiously, three of the 12 healthy volunteers were not able to reliably activate areas in the brain used when making a fist or wiggling toes, even though they were very much aware of their surroundings.
Cruse said patients in a vegetative state may have been much more motivated to do the task because they were eager to show that they were aware of their surroundings.
Owen said the findings are preliminary, but they show it is possible to use less expensive equipment to reassess patients in a vegetative state who may have been misdiagnosed.
In the future, the researchers envision using the devices to help people communicate with the outside world, giving doctors important information about their state of mind and whether or not they are in pain.
"All of the technological and scientific building blocks are already in place. We know we can develop brain computer interfaces to move cursors and even spell out words," Owen said.
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