Scientists have for the first time been able to predict how much pain people are feeling by looking at images of their brains.

The new study led by the University of Colorado Boulder may lead to the development of reliable methods doctors can use to objectively quantify a patient`s pain.

Currently, pain intensity can only be measured based on a patient`s own description, which often includes rating the pain on a scale of one to 10.

Objective measures of pain could confirm these pain reports and provide new clues into how the brain generates different types of pain.

The new research results also may set the stage for the development of methods using brain scans to objectively measure anxiety, depression, anger or other emotional states.

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

The research team, which included scientists from New York University, Johns Hopkins University and the University of Michigan, used computer data-mining techniques to comb through images of 114 brains that were taken when the subjects were exposed to multiple levels of heat, ranging from benignly warm to painfully hot.

With the help of the computer, the scientists identified a distinct neurologic signature for the 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.

Going into the study, the researchers expected that if a pain signature could be found it would likely be unique to each individual.

If that were the case, a person`s pain level could only be predicted based on past images of his or her own brain.

But instead, they found that the signature was transferable across different people, allowing the scientists to predict how much pain a person was being caused by the applied heat, with between 90 and 100 percent accuracy, even with no prior brain scans of that individual to use as a reference point.

The results of the study do not yet allow physicians to quantify physical pain, but they lay the foundation for future work that could produce the first objective tests of pain by doctors and hospitals.

To that end, Wager and his colleagues are already testing how the neurologic signature holds up when applied to different types of pain.

The findings are published in the New England Journal of Medicine.