AI app analyzes facial expressions to detect patient pain, experts skeptical

An AI-powered smartphone app called PainChek is now being used in hospitals and care settings to assess patient pain levels by analyzing facial movements like lip raises and brow pinches. While the technology shows promise for evaluating pain in patients who cannot communicate their discomfort—such as those with dementia—it highlights the fundamental challenge of measuring something as deeply subjective and personal as pain.

How it works: PainChek combines computer vision analysis with manual assessment to create pain scores for patients.

• The app analyzes small facial movements and micro-expressions that indicate discomfort or pain.
• Users must also complete a separate checklist to identify other signs of pain the patient might be displaying.
• The technology is already being deployed in hospitals and care facilities to assist healthcare providers.

The subjective pain problem: Pain assessment has long frustrated both patients and doctors due to its inherently personal nature.

• Traditional pain scales asking patients to rate discomfort from 1-10 prove notoriously difficult and inconsistent.
• Individual pain tolerance, past experiences, mood, and expectations all influence how people perceive and report their pain levels.
• Historical research from the 1940s showed wounded soldiers requested pain relief far less frequently than similarly injured civilians, illustrating how context shapes pain expression.

Current limitations: The technology faces significant constraints that limit its clinical impact.

• PainChek is validated against subjective pain reports, meaning it’s “baked into the system” with the same fundamental limitations.
• The app offers little additional value for patients who can already communicate their pain levels effectively.
• Even accurate pain detection doesn’t solve treatment challenges, particularly for chronic pain conditions where therapeutic options remain limited.

What experts think: Pain researchers remain skeptical about technology’s ability to truly quantify human suffering.

• “Subjective report is the gold standard, and I think it always will be,” says Stuart Derbyshire, a pain neuroscientist at the National University of Singapore.
• Previous attempts using brain scans to measure pain have failed to become routine clinical tools after 15 years of development.
• Derbyshire doesn’t believe we’ll ever have a reliable “pain-o-meter” that can definitively measure what someone is experiencing.

Why this matters: While AI pain assessment tools may help with specific populations who cannot self-report, they underscore the irreplaceable value of human communication in healthcare and the complex challenge of quantifying subjective experiences through technology.