Traditionally, doctors diagnose severely injured people as "vegetative" when their eyes can't track movement and they can't wiggle any of their fingers. But a new medical study suggests that some of these patients may actually be fully conscious and aware — but trapped in unresponsive bodies. Researchers used EEG devices to map electrical activity in the brains of vegetative people. Twenty percent of them exhibited normal brain activity that matched what you'd expect to see in somebody who was fully aware.

This study can't definitively answer the question of whether these patients really are conscious and trying to communicate. But it does suggest, chillingly, that people may have been misdiagnosed as vegetative.

According to Benedict Carey, writing in the New York Times:

An estimated 25,000 Americans with brain injuries are living in an unresponsive state diagnosed as vegetative, and friends and family members typically long for some way to reach through the empty mask - to see whether there is any life behind those familiar eyes. If the new approach holds up, an EEG could provide that, and perhaps even a way to communicate.

"My personal view is that you don't introduce anything like this into routine clinical practice until" larger trials at multiple clinics confirm its value, said Joseph T. Giacino, of Harvard, director of rehabilitation neuropsychology at Spaulding Rehabilitation Hospital, who was not involved in the research. "But it sure looks as if there's not just a little bit of consciousness but a lot" in patients who had been deemed unresponsive.

The researchers hope that their discoveries with EEG devices will help them to communicate with patients previously thought to be non-responsive.

Read the scientific study in The Lancet.