Facial expression and pain assessment in the pediatric patient: The primal face of pain

PURPOSE. This paper aims to explore the role of facial expression in pediatric pain assessment. A comparison of tools employing facial expression methodology is presented. The concept of the primal face of pain (PFP) is introduced. CONCLUSION. The PFP offers an explanation to the utility and deficiency of facial pain scales and facial expression in pain assessment. PRACTICE IMPLICATIONS. The complexities of pain measurement should preclude the clinical application of untested instruments. For reported tools, a careful evaluation of the psychometric properties and the clinical context must precede application. The concept of the PFP warns against the application of facial pain scales as proxy measures in their intended population. Reliance on facial expression to assess pain in the school-age child is imprecise.