And you thought it was Botox! Research published online in Emergency Medicine Journal found patients with serious heart and lung conditions don't have the normal range of facial expressions. In particular, they seem to lack the ability to register surprise. The authors note, “patients with serious cardiopulmonary diseases tended to hold their faces neutral,” and so suggest this information could be used by busy emergency room doctors who must gauge which patient to treat first and which tests might be required.

To test diagnostic accuracy in an emergency room, a team of researchers conducted a pilot study at Carolinas Medical Center, an academic urban hospital located in Charlotte, N.C., between May and September 2011. Patients participating in the study viewed three stimulus slides intended to evoke a change in their facial expressions on a laptop computer. At the same time, a webcam recorded the patients’ facial expressions. Then, independent observers examined the webcam videos and analyzed participants’ facial expressions using the Facial Action Coding System (FACS), which scores changes in facial muscle activity reflecting the extent of smiling, frowning, and surprise. Meanwhile, doctors examined the patients for serious heart or lung disease, including acute coronary syndrome (such as heart attack or unstable angina); a blood clot in the lung (pulmonary embolism); pneumonia; problems in a major artery or gut; and new cancers. Finally, doctors monitored the patients for two weeks.

All told, participants in this study included just 50 people. The average age was 52, with 80 percent having no past medical history and 30 percent being women. During the monitoring period, eight patients (16 percent) developed serious heart or lung disease. Among the 42 considered not to have any serious health problem when they entered the ER, two developed worsening chronic obstructive pulmonary disease, two developed heart failure, and one an irregular heart rhythm (atrial fibrillation).

Comparing the health results to the analyses of webcam recordings, the researchers discovered that those patients with chest pain and shortness of breath who had a potentially serious heart or lung condition showed a significantly narrower range of facial expression than patients who did not have these health problems. In fact, the ability to express surprise most strongly demarcated those with serious heart and lung problems from those without these problems.

“This work was motivated by years of research experience that has suggested a hidden layer in physician reasoning when they decide whether or not to prioritise life threatening conditions at the top of their differential diagnosis list,” wrote the authors. Often, when asked how they quickly decide to treat one patient before another, doctors will say abnormal vital signs, past medical history, and "he or she looked sick." The researchers believe their work, though preliminary, adds credibility to the "blink" theory — that an experienced doctor’s quick take may be correct more often than not.

Source: Kline JA, Neumann D, Haug MA, Kammer DJ, Krabill VA. Decreased facial expression variability in patients with serious cardiopulmonary disease in the emergency care setting. Emergency Medicine Journal. 2014.