Behavioral and Physiological Signs for Pain Assessment in Preterm and Term Neonates During a Nociception-Specific Response: A Systematic Review

Assessment and treatment of neonatal pain is difficult because current scales are rarely validated against brain-based evidence. We sought to systematically evaluate published evidence to extract validation of the most promising markers of neonatal pain. We searched four databases using germane MeSH terms. We focused on assessments of pain and/or nociception that had at least two measures among behavioral, physiological, or cortical components in preterm and/or term neonates. We evaluated studies for quality of evidence and strength of recommendations using standardized tools. Fifteen articles met our inclusion criteria. Among the behavioral components uncovered in this review, the withdrawal reflex and changes in facial expression are the most strongly associated with nociception-specific brain activity. These associations may be influenced by gestational age and change over time. Physiological signs, such heart rate and oxygen saturation, have little to no association with this type of response. Current assessments of neonatal pain include behavioral components that are associated with nociceptive processing, but also other less valid components, while omitting newer measures based on neuroscientific research.