New Techniques Detect Consciousness in Vegetative Patients

People in a “vegetative state” may have far more brain activity than previously thought, LiveScience reports:

…researchers looked at 32 comatose patients and 26 healthy people. Some of the comatose patients were diagnosed as “minimally conscious,” meaning there was some evidence that they may have retained some awareness of their surroundings (for example, the patient could follow simple commands, such as squeezing a finger). But others were diagnosed as “vegetative,” which means they were thought to have lost all conscious awareness, even though they could breathe on their own or open their eyes.

The researchers examined participants’ brain waves using electroencephalography (EEG) and applied mathematical tools to the EEG data to find patterns of communication across brain regions. The researchers then compared these patterns in the comatose patients’ brains with those of healthy people.

As expected, the brain-activity patterns in the comatose patients’ brains differed from those of the healthy participants. Healthy, conscious brains showed “rich and diversely connected networks,” which were lacking in the comatose patients’ brains, the researchers said. [Top 10 Mysteries of the Mind]

However, some comatose patients who were thought to be completely vegetative actually showed some patterns similar to those of healthy people. These were the patients who, despite being diagnosed as vegetative, had been suggested to have some level of awareness in previous brain imaging experiments. For example, although the patients did not perform any physical movements in response to commands, brain imaging showed that when they were told to imagine doing a physical activity, such as playing tennis, the area of the brain responsible for controlling movement, lit up.

Some vegetative patients who show signs of hidden awareness have remarkably well-preserved networks similar to healthy adults,” the researchers wrote.

It’s a little late to help Terri Schiavo and other victims of medical homicide, but any progress is welcome.

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