Scientists use brain scans to objectively measure pain

Doctors can measure your blood pressure, your weight, your cholesterol and your blood sugar. They can take X-rays of your bones, ultrasounds of your guts and electrocardiograms of your heart.

But even in 2013, the only way a doctor can measure your pain is to ask: How much does it hurt?

A new study led by researchers at the University of Colorado Boulder lays the groundwork for changing that. In a study published in the New England Journal of Medicine, the scientists showed that they can objectively measure pain — with between 90 and 100 percent accuracy — by looking at scans of people’s brains.

“Right now, there’s no clinically acceptable way to measure pain and other emotions other than to ask a person how they feel,” said Tor Wager, associate professor of psychology and neuroscience at CU-Boulder and lead author of the paper.

The scientists used data-mining techniques to help them comb through brain images that were taken when subjects were exposed to multiple levels of heat, ranging from benignly warm to painfully hot. With the help of a computer, the researchers were able to identify a distinct neurologic signature for pain.

“We found a pattern across multiple systems in the brain that is diagnostic of how much pain people feel in response to painful heat,” Wager said.

Not only was the new signature able to tell the scientists how much physical pain people were in, but it also could not be fooled by emotional pain. A previous study showed that the brain activity of people who have just been through a relationship breakup — and who were shown an image of the person who rejected them — is similar to the brain activity of someone feeling physical pain.

But when Wager’s team tested to see if the newly defined neurologic signature for heat pain would also pop up in the data collected earlier from the heartbroken participants, they found that the signature was absent.

The technique described in the new study, which is specific to painful heat, is not yet ready for use by doctors trying to diagnose clinical pain. But Wager and his colleagues are already working to see if they can apply the same neurologic signature to other types of physical pain, such as mechanical pain or pain in different parts of the body.

“We’re also looking towards using these same techniques to develop measures for chronic pain," Wager said. "The pattern we have found is not a measure of chronic pain, but we think it may be an ‘ingredient’ of chronic pain under some circumstances. Understanding the different contributions of different systems to chronic pain and other forms of suffering is an important step towards understanding and alleviating human suffering.”


Listen to an interview with Tor Wager on NPR's Morning Edition:


Read the full press release here.