Enhancing Doctor–Patient Communication Through Nonverbal Cues: A FACS-Based Study

Background: Nonverbal cues are integral to clinical communication, yet there is limited anatomically precise quantification of clinician facial behaviour. Objectives: To quantify clinician smiling during standardised consultations and determine its predictive value for patient-rated communication outcomes. Methods: Fifty-two third-semester medical students conducted seven-minute simulated consultations with standardised patients. Certified coders scored facial Action Units (AUs) for duration and intensity, achieving high interrater reliability. Smiling AUs were compared between the speaking and listening phases using paired tests. Hierarchical regression analyses, controlling for clinician sex, evaluated smiling and additional facial movements as predictors of standardised patient ratings on global communication and comfort scales. Results: Smiling occurred significantly more during speaking than listening. Smiling intensity and duration explained a substantial proportion of variance in patient-rated communication quality and comfort. Additional facial movements contributed further predictive value for communication quality but not for comfort ratings. Neither smiling nor other facial behaviours predicted clinician self-ratings or expert evaluations. Conclusions: Clinician smiling, precisely quantified via Facial Action Coding System (FACS), robustly predicts patient perceptions of communication quality and comfort. Incorporating targeted nonverbal training into medical education may enhance patient satisfaction and trust.