Age related differences in infant pain expression and parental judgements of pain throughout the first year of life
Creators: name: Nader, Rami
Publisher: name: University of British Columbia
Year: 2009

description: For over two decades, researchers have studied the expression of pain in young infants to unlock the nature of this powerful experience early in life, with these studies resulting in the discrediting of numerous myths about infant pain (e.g., infants are insensitive to pain). The more useful measures of infant pain to emerge from this research examine facial activity, body movement and cry characteristics. To date, however, there has been little effort to examine the developmental progression of these pain behaviours throughout early infancy. This work has great relevance for caregivers of pre-verbal infants who often are asked to assess the presence or absence and severity of pain an infant may be experiencing. This can be a challenging task, as they must extract information specific to pain from apparent generalized distress reactions, substantial variability in response among children, and similarities in response to noxious and non-noxious aversive events, among other influences on their judgments. The extent to which parental assessment accommodates changes in the nature of pain (and its expression) with infant development has received little study and is not well understood at present. The purposes of the present study were to: a) Describe how, and if, pain expression differs throughout the first year of life; b) Illustrate how parent perceptions and assessment of pain change with the development of the infant; and c) Explore the relationship between parental assessments and behavioural indices of infant pain. The study used the sociocommunications model of pain as a theoretical framework from which to describe the interplay between infant behaviour and caregiver response. Participants in this cross-sectional study were 160 infants (40 infants in each of four age groups: 2-, 4-, 6- and 12-months) receiving routine immunization injections and their parents. Following immunization procedures, parents provided judgments of the amount of pain their infants experienced and rated the importance of various cues in making their judgments. Infant pain experiences were assessed using measures of facial activity, body movement and cry characteristics. Results indicated almost no age related differences in pain expression, with only minor differences in body movement profile. However, significant differences in parental assessments of pain were observed, with parents attributing greater pain to younger infants compared to older infants. These findings were in contrast to the findings that behavioral cues (cry, facial activity and body movement) were reported by all parents to be the most important factors in making their pain judgments, yet these changed minimally. Thus, systematic variations in parental judgements of pain across this age span were influenced to a greater extent by other factors and were not solely dependent on the behavioural display of the infants. These findings suggest that variations in caregiver attributions of pain across the first year of life may result from caregiver characteristics (cognitive biases, sensitivity, knowledge and emotional availability to the infant). Further research is required to examine age related differences in infant recovery from painful events and factors influencing parental judgments of infant pain.