H

aving a family member in a coma is the ultimate waiting game. The person might wake up next week. Or next year. Or never.

A new study from doctors in Europe may help reduce that uncertainty. By scanning an area of the brain often overlooked by neurologists, the researchers found a method that might predict whether or not a patient will recover from a coma. They reported the findings Wednesday in the journal Neurology.

“It’s very sophisticated and important work they’re doing here,” said Alexander Lin, a brain imaging specialist at Boston’s Brigham and Women’s Hospital, who was not involved in the study. “The data are very convincing.”

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In the study, researchers from France, Italy, and Switzerland scanned the brains of 27 comatose patients a few days after they had become unresponsive. Some had suffered heart attacks, which cut off oxygen to the brain. Others had endured severe brain damage during car accidents.

Then, the researchers waited. Comas can last anywhere from several days to several years, and the study authors wanted to know if the brain scans of those who recovered looked different from the scans of those who remained unconscious. They used a technique called functional magnetic resonance imaging, or fMRI, which measures brain activity by detecting changes associated with blood flow.

Four of the study subjects emerged from their comas in the first three months. Looking back at the brain scans from these patients when they were unconscious, the researchers saw a different pattern of brain activity compared to those who didn’t recover. In fact, the connections between brain regions in these four individuals were comparable to a control group of 14 people who never suffered brain damage.

“We found that the more you lose this connection, the worse is going to be the outcome,” said Dr. Stein Silva, an intensive care physician at the University Teaching Hospital of Purpan in Toulouse, France, who led the study.

Silva and his colleagues focused on an area deep at the back of the brain called the posterior cingulate cortex, or PCC. Neuroscientists have found that it plays a role in regulating consciousness, but neurologists — the clinicians who actually treat brain injuries — have largely ignored the structure, because it isn’t often specifically affected by lesions.

By using fMRI to see what other regions of the brain light up at the same time as the PCC, these researchers could tell it often communicates with a specific area at the front of the brain called the medial prefrontal cortex. If an injury or a heart attack weakens that communication, then the chances are slim that the patient will recover in the first three months.

This test won’t be used in the clinic anytime soon, though. Larger studies are still needed to confirm the study results, cautioned Lin. But if the findings hold up, brain scans could help give hope to some families with loved ones in comas, and help others better prepare to provide long-term care. “Being more informed is always positive,” he said.

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