Facial expressions of pain and emotions in chronic TMD patients.

This research was designed to identify and validate facial expressions of pain occurring in a clinical chronic pain condition. Facial expressions of 28 patients with chronic temporomandibular disorder pain were videotaped during a painful clinical examination procedure and coded using an anatomically based system. Characteristics of the expressions occurring most frequently were compared with self-report measures of pain, anxiety, depression and somatic symptoms. The frequency, duration and intensity of the identified expressions were dependably correlated with pain report, but unrelated to self report of other somatic symptoms, depression or anxiety. A small number of facial expressions of specific negative emotions were also observed; pain report and pain facial expressions were higher for persons showing a greater number of negative affects. These findings support the promise of facial expressions as measures of clinical pain.