The impact of parental contact upon cortical noxious-related activity in human neonates

Abstract

Background: Neonates display strong behavioural, physiological and cortical responses to tissue-damaging procedures. Parental contact can successfully regulate general behavioural and physiological reactivity of the infant, but it is not known whether it can influence noxious-related activity in the brain. Brain activity is highly dependent upon maternal presence in animal models, and therefore this could be an important contextual factor in human infant pain-related brain activity.

Methods: Global topographic analysis was used to identify the presence and inter-group differences in noxious-related activity in three separate parental contexts. EEG was recorded during a clinically required heel lance in three age and sex-matched groups of neonates (a) while held by a parent in skin-to-skin (n = 9), (b) while held by a parent with clothing (n = 9) or (c) not held at all, but in individualized care (n = 9).

Results: The lance elicited a sequence of 4-5 event-related potentials (ERPs), including the noxious ERP (nERP), which was smallest for infants held skin-to-skin and largest for infants held with clothing (p=0.016). The nERP was then followed by additional and divergent long-latency ERPs (> 750 ms post-lance), not previously described, in each of the groups, suggesting the engagement of different higher level cortical processes depending on parental contact.

Conclusions: These results show the importance of considering contextual factors in determining infant brain activity and reveal the powerful influence of parental contact upon noxious-related activity across the developing human brain.

Significance: This observational study found that the way in which the neonatal brain processes a noxious stimulus is altered by the type of contact the infant has with their mother. Specifically, being held in skin-to-skin reduces the magnitude of noxious-related cortical activity. This work has also shown that different neural mechanisms are engaged depending on the mother/infant context, suggesting maternal contact can change how a baby's brain processes a noxious stimulus.

FIGURE 1

Summary of ERP comparison across groups. Summary of comparison steps (rectangles) across ERPs identified in the different groups and interpretation of the results (ovals). skin‐to‐skin (S‐S), cot‐individualized care (C‐IC), and held with clothing (H)

FIGURE 2

Event‐related potentials and Global Field Power across groups in response to a clinically required heel lance. ERPs and GFPs following a heel lance (vertical dashed lines) for infant in skin‐to‐skin (S‐S, red), cot‐individualized care (C‐IC, blue) and held with clothing (H, yellow). Average EEG recording at each electrode in the three groups (a); average GFPs for the three groups (b). Coloured and grey blocks at the bottom of panel (b) respectively indicate periods of topographic consistency within each group and for the grand average. Vertical solid lines indicate the peak group GFP within each period. Peak group GFPs within the same grand average consistency period were considered as having a comparable latency

FIGURE 3

Topographic and magnitude differences of the cortical response to the heel lance according to parental contact. Topographic maps at the latency of peak ERP for each group (Figure 2b). Time windows are based on the topographically consistent events from the grand average and the peak latency for each group fell within this time window. Brackets mark significant differences in topography (DISS) or magnitude (GFP). Skin‐to‐skin (S‐S, red), cot‐individualized care (C‐IC, blue), held with clothing (H, yellow)

FIGURE 4

Behavioural and heart rate scores. Average facial behaviour (a) and heart rate (b) for the three groups, Skin‐to‐skin (S‐S, red), held with clothing (H, yellow), and cot‐individualized care (C‐IC, blue). Dashed lines indicate the time of the lance