Facial micromovements may help doctors measure pain more accurately

Researchers at Rutgers University-New Brunswick are working to measure pain more accurately beyond the single, subjective question patients are often asked: "On a scale of 1 to 10, how bad is your pain?"

Using video analysis and artificial intelligence (AI), the team tracked facial muscle activity alongside heart rate variability-a measure of the timing between heartbeats. This revealed a direct link between micromovement spikes and the body's physiological response: As pain intensified, heart rhythms became increasingly irregular, with the most pronounced changes appearing around the eyes.

"A higher cognitive load essentially crowds out the pain," Torres said. "This kind of engagement may act as a natural distractor, offering a potential therapeutic tool for redirecting attention."

Torres, a computational neuroscientist, uses mathematical modeling to decode internal states through subtle body language. In her studies of nonverbal autism, these patterns provided vital clues to physical distress that clinicians and caregivers might otherwise miss.

By applying this approach to facial movements and heart rhythms, Torres suggests clinicians can objectively evaluate pain in patients who are not able to describe their symptoms including young children, stroke survivors, and individuals with dementia.

"Right now, we rely on caregivers' interpretations, which are valuable but incomplete," Torres said. "This gives us a window into the physiology itself."

"You can see whether a medication is working, how quickly it's taking effect, and whether adjustments are needed," Torres said. "It's a much more precise way to monitor outcomes."

Torres said the simplicity of a short facial scan is what could eventually make the approach useful beyond specialized research settings.

"Instead of a piece of paper with emojis, you have a digital dashboard where you can measure yourself day to day," she said. "It gives people a sense of control over their own biorhythms."

Source:

Rutgers University

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