The quest for a reliable pain biomarker remains elusive. Among the limited options available: patient facial expressions and their own reports of how much they hurt. But as Medscape Medical News reports, researchers from the University of Colorado, Boulder, believe they have found a distinct, reliable neurological pattern that appears to reflect response to pain caused by heat.
Similarly, that pattern diminished when researchers introduced an opioid analgesic to treat pain symptoms. And functional MRI made it all possible.
Their work is published in The New England Journal of Medicine. The researchers themselves caution that more studies are necessary to determine where the neurological signature predicts clinical pain. But Tor D. Wager, one of the study authors, told Medscape that their fMRI test could help diagnose pain in patients who can't express what they're feeling, such as the very young or old, or patients with cognitive problems. And in doing so, having a new reliable pain biomarker could greatly help with both pain diagnosis and treatment.
The researchers pursued four studies involving 114 healthy men and women. For two, after enacting heat-induced pain, they used fMRI to successfully spot a reliable neurological signature in several parts of the brain, with both high sensitivity and specificity. In one of the studies, researchers were also able to use the brain signature to tell the difference between physical and social pain (recalling a relationship breakup), which can hit the same brain areas. A fourth study used the drug remifentanil to successfully reduce the pain-related neurological response generated by heat, the researchers note.
A year ago, scientists from Harvard Medical School and the Martinos Center for Biomedical Imaging detected changes in connectivity between regions of the brain through their study of the brains of people with chronic low back pain and discogenic pain. Stanford researchers have also developed an algorithm to diagnose pain.