The National Institutes of Health is pushing for development of what its director, Dr. Francis Collins, calls a “pain-o-meter.”
Spurred by the opioid crisis, the goal is not just to signal how much pain someone’s in, it is to determine what kind it is and what drug might be the most effective.
“We are not creating a lie detector for pain,” stressed David Thomas of NIH’s National Institute on Drug Abuse, who oversees the research. “We do not want to lose the patient voice.”
Around the country, NIH-funded scientists have begun studies of brain scans, pupil reactions and other possible markers of pain in hopes of finally “seeing” the ouch so they can better treat it. It’s early-stage research, and it’s not clear how soon any of the attempts might pan out.
“There won’t be a single signature of pain,” Dr. Thomas predicted. “My vision is that someday we’ll pull these different metrics together for something of a fingerprint of pain.”
NIH estimates 25-M people in the US experience daily pain.
The eyes offer a window to pain centers in the brain, said the director of pain research at Children’s Sheikh Zayed Institute for Pediatric Surgical Innovation.
The Big Q: How?
The Big A: Some pain-sensing nerves transmit “ouch” signals to the brain along pathways that also alter muscles of the pupils as they react to different stimuli. The device tracks pupillary reactions to light or to non-painful stimulation of certain nerve fibers, aiming to link different patterns to different intensities and types of pain.
Consider the shooting hip and leg pain of sciatica: “Everyone knows someone who has been started on oxycodone for their sciatic nerve pain. And they will tell you that they feel it, it still hurts, they just do not care.”
An opioid like oxycodone brings some relief by dulling the perception of pain but not its transmission, while a different kind of drug might block the pain by targeting the culprit nerve fiber.
Certain medications also can be detected by other changes in a resting pupil.
Last month the Food and Drug Administration announced it would help AlgometRx, a biotech company, speed development of the device as a rapid drug screen.
Looking deeper than the eyes, scientists at Harvard and Massachusetts General Hospital found MRI scans revealed patterns of inflammation in the brain that identified either fibromyalgia or chronic back pain.
Other researchers have found changes in brain activity; where different areas “light up” on scans that signal certain types of pain. Still others are using electrodes on the scalp to measure pain through brain waves.
Ultimately, NIH wants to uncover biological markers that explain why some people recover from acute pain while others develop hard-to-treat chronic pain.
The brain changes with pain, and a Zero-to-10 scale or a happy-face scale does not capture anywhere near the totality of the pain experience.