Pain activates a defined area of the somatosensory and motor cortex in newborn infants

Empathy at birth: Mother's cortex synchronizes with that of her newborn in pain

Early neonatal relation with the caregiver is vital for newborn survival and for the promotion of an appropriate neural development. The aim of this study was to assess if the empathic cortical response of a mother to her baby's pain is synchronized with the neonatal cortical response to the painful stimulation. We used hyperscanning, a functional neuroimaging approach that allows studying functional synchronization between two brains. Sixteen mother-newborn dyads were recruited. Maternal and neonatal cortical activities were simultaneously monitored, by near-infrared spectroscopy, during a heel prick performed on the baby and observed by the mother. Multiple paired t test was used to identify cortical activation, and wavelet transform coherence method was used to explore possible synchronization between the maternal and neonatal cortical areas. Activations were observed in mother's parietal cortex, bilaterally, and in newborn's superior motor/somatosensory cortex. The main functional synchronization analysis showed that mother's left parietal cortex activity cross-correlated with that of her newborn's superior motor/somatosensory cortex. Such synchronization dynamically changed throughout assessment, becoming positively cross-correlated only after the leading role in synchronizing cortical activities was taken up by the newborn. Thus, maternal empathic cortical response to baby pain was guided by and synchronized to the newborn's cortical response to pain. We conclude that, in case of potential danger for the infant, brain areas involved in mother-newborn relationship appear to be already co-regulated at birth.

Effects of Temperature and Position Change on Neonatal Brain Regional Oxygen Saturation in Tub Bathing: A Prospective Study

INTRODUCTION

A major goal in neonatal medicine is to reduce stress as much as possible in routine care. Bathing is one of the important routine cares for neonates, but it makes a big environmental change for them. We aimed to examine whether water temperature, room temperature, and position changes in tub bathing serve as noxious stimuli to neonates.

METHODS

This prospective trial was performed in full-term and non-low-birth-weight neonates admitted to the hospital between July 2020 and March 2021. Those with underlying diseases, fetal distress, infection, and other medical conditions were excluded. Measurements were taken during the neonates' first tub bath since birth, which was performed by a trained nurse. Changes in regional oxygen saturation (rSO₂), determined using near-infrared spectroscopy, and water and room temperature, were examined at five different time points: upon entering the bath, head washing, position change, exiting the bath, and during the 3 min after bathing.

RESULTS

In total, 17 neonates were analyzed. No changes in rSO₂ due to head washing or position change were observed; however, rSO₂ significantly decreased upon entering (78.5 ± 4.1% vs. 75.7 ± 4.1%, p < 0.001) and exiting the bath (75.8 ± 5.7% vs. 74.4 ± 5.4%, p < 0.04). The rate change in rSO₂ upon entering the bath showed a significant inverse correlation with water temperature (r =  - 0.53, p < 0.03), and there were no significant correlations between rSO₂ and water or room temperature upon exiting the bath. There was no change in body skin temperature before and after bathing, but rSO₂ gradually decreased during the 3 min after bathing.

CONCLUSIONS

Neonates may perceive certain temperatures during bathing as noxious stimuli. Therefore, methods to minimize stress associated with bathing should be implemented to reduce the difference between water temperature and room temperature during bathing.

TRIAL REGISTRATION

This trial has been registered at UMIN repository with the trial number UMIN000041045 ( https://upload.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000046500 ). The date of the final dataset was April 01, 2021.

State of the Art in Parent-Delivered Pain-Relieving Interventions in Neonatal Care: A Scoping Review

Introduction: Parents' active involvement during painful procedures is considered a critical first step in improving neonatal pain practices. Of the non-pharmacological approaches in use, the biopsychosocial perspective supports parent-delivered interventions, in which parents themselves mediate pain relief, consistent with modern family-integrated care. This scoping review synthesizes the available research to provide an overview of the state of the art in parent-delivered pain-relieving interventions. Methods: A scoping review was performed to achieve a broad understanding of the current level of evidence and uptake of parent-driven pain- and stress-relieving interventions in neonatal care. Results: There is a strong evidence for the efficacy of skin-to-skin contact and breastfeeding, preferably in combination. These parent-delivered interventions are safe, valid, and ready for prompt introduction in infants' pain care globally. Research into parents' motivations for, and experiences of, alleviating infant pain is scarce. More research on combined parent-delivered pain alleviation, including relationship-based interventions such as the parent's musical presence, is needed to advance infant pain care. Guidelines need to be updated to include infant pain management, parent-delivered interventions, and the synergistic effects of combining these interventions and to address parent involvement in low-income and low-tech settings. Conclusions: A knowledge-to-practice gap currently remains in parent-delivered pain management for infants' procedure-related pain. This scoping review highlights the many advantages of involving parents in pain management for the benefit not only of the infant and parent but also of health care.

Venipuncture activates the cerebral cortex in children with intellectual disability

OBJECTIVE

To evaluate the pattern of cortical activation during a painful procedure, such as a venipuncture, in children with intellectual disability and compare it with that of cognitively healthy children.

STUDY DESIGN AND SETTING

A cohort study was conducted and cortical activation was assessed by multichannel cerebral near-infrared spectroscopy to monitor variations in oxyhaemoglobin and deoxyhaemoglobin (Hbb) in children with and without intellectual disability during a venipuncture for blood sampling with topical anaesthesia. Pain and distress were assessed as well using different validated pain scales (visual analogue scale and Non-Communicating Children's Pain Checklist-Postoperative Version for children with intellectual disability), and compared between groups.

PARTICIPANTS

16 children with severe to profound intellectual disability and 20 cognitively healthy peers (age range: 4-17 years).

RESULTS

When Hbb was analysed, children with intellectual disability exhibited a bilateral activation of the somatosensory (p<0.006) and right motor cortex (p=0.0045), whereas cognitively healthy peers never showed a cortical activation. Children with intellectual disability also showed more pain than controls (p=0.001).

CONCLUSIONS

When subjected to a painful procedure, only children with intellectual disability show an activation of the cerebral cortex, even if topical anaesthesia is applied, and express more pain than cognitively healthy peers. The role of other issues in painful procedures, such as anxiety, fear or physical restraint, deserves further investigation.

The role of the spinal cyclooxygenase (COX) for incisional pain in rats at different developmental stages

BACKGROUND

Cyclooxygenase enzymes (COX)-1 and COX-2 are important targets for pain relief after surgery, but the spinal contribution of both isoforms is still unclear, e.g., from a developmental point of view. Here, we studied changes of spinal COX-1 and COX-2 expression and their functional relevance in rats of different ages for pain-related behaviour after incision.

METHODS

Mechanical paw withdrawal thresholds (PWT) were assessed before and after incision and after intrathecal administration (IT) of SC-560 (COX-1 inhibitor) or NS-398 (COX-2 inhibitor) in rats aged 5, 14 and 28 days (P5, P14, P28). Furthermore, spinal expressions of COX m-RNA and proteins were investigated.

RESULTS

In P5 rats, only IT-administered NS-398 but not SC-560 significantly reversed the decreased PWT after incision. In P14 rats, none of the substance modified PWT, and in P28 rats, only SC-560 increased PWT. Spinal COX-2 mRNA and protein were increased in P5 but not in P14 and P28 rats after incision. Whereas COX-2 is located in spinal neurons, COX-1 is mainly found in spinal microglia cells.

CONCLUSION

Our results demonstrate a possible developmental transition from COX-2 to COX-1 activation. Whereas in adult rats spinal COX-1 but not COX-2 is involved in pain-related behaviour after incision, it seems opposite in P5 rats. Interestingly, in P14, neither COX-1 nor COX-2 seems to play a role. This switch may relate to altered neuronal/microglia activation. Our findings indicate specific mechanisms to pain after incision that are age-dependent and may guide further research improving paediatric pain management.

SIGNIFICANCE

Postoperative pain in pediatric patients after surgery is still poorly controlled; this might contribute to long-lasting alteration in the nociceptive system and prolonged chronic pain. Here we show a possible developmental switch in the COX-dependent pathway for nociceptive spinal transmission that may explain why pain management in young children needs to be related to age-dependent mechanisms.

Nociception and the neonatal brain

Measuring brain activity in infants provides an objective surrogate approach with which to infer pain perception following noxious events. Here we discuss different approaches which can be used to measure noxious-evoked brain activity, and discuss how these measures can be used to assess the analgesic efficacy of pharmacological and non-pharmacological interventions. We review factors that can modulate noxious-evoked brain activity, which may impact infant pain experience, including gestational age, sex, prior pain, stress, and illness.

Assessment of pain in newborn infants

Hospitalized newborn infants experience pain that can have negative short- and long-term consequences and thus should be prevented and treated. National and international guidelines state that adequate pain management requires valid pain assessment. Nociceptive signals cause a cascade of physical and behavioral reactions that alone or in combination can be observed and used to assess the presence and intensity of pain. Units that are caring for newborn infants must adopt sufficient pain assessment tools to cover the gestational ages and pain types that occurs in their setting. Pain assessment should be performed on a regular basis and any detection of pain should be acted on. Future research should focus on developing and validating pain assessment tools for specific situations.

Infant Analgesia With a Combination of Breast Milk, Glucose, or Maternal Holding

OBJECTIVES

We studied neonatal cortical brain response to 4 types of nonpharmacological analgesia (oral glucose, expressed breast milk, maternal holding plus oral glucose, breastfeeding). We aimed to assess the differential effect of oral solutions (glucose, breast milk) given alone or combined with the maternal-infant relationship (holding, breastfeeding).

METHODS

Eighty healthy term newborns undergoing a heel stick were randomly assigned to 4 parallel groups of 20 infants each: group 1, infants received a glucose solution on a changing table; group 2, infants received expressed breast milk on a changing table; group 3, infants received a glucose solution in their mothers' arms; and group 4, infants were breastfed by their mothers. Cortical activation in parietal, temporal, and frontal cortices was assessed by multichannel near-infrared spectroscopy. Pain expression was also evaluated.

RESULTS

Oral glucose alone or combined with maternal holding was associated with no cortical activation during heel stick. Expressed breast milk was associated with localized bilateral activation of somatosensory and motor cortices (P < .01). Breastfeeding was associated with extensive bilateral activation of somatomotor, somatosensory, and right parietal cortices (P < .01). Pain expression was lower with the maternal-infant relationship (P = .007).

CONCLUSIONS

Oral glucose, either alone or combined with maternal holding, appears to block or weaken cortical pain processing. Breast milk alone is associated with localized cortical activation. Breastfeeding is associated with extensive activation and may act by extending cortical processing. Maternal relationship, both combined with oral glucose and in breastfeeding, shows the greatest analgesic effect, although the neural patterns involved are distributed differently.

What do we really know about newborn infant pain?

NEW FINDINGS

What is the topic of this review? Pain in infancy. What advances does it highlight? New neurophysiological research on pain processing in the human infant brain. Increased awareness of pain in the newborn has led to the development of numerous assessment tools for use in neonatal intensive care units. Here, I argue that we still know too little about the neurophysiological basis for infant pain to interpret data from clinical observational measures. With increased understanding of how the neural activity and CNS connections that underlie pain behaviour and perception develop in the newborn will come better measurement and treatment of their pain. This review focuses upon two interconnected nociceptive circuits, the spinal cord dorsal horn and the somatosensory cortex in the brain, to highlight what we know and what we do not know about infant pain. The effectiveness of oral sucrose, widely used in clinical practice to relieve infant pain, is discussed as a specific example of what we do not know. This 'hot topic review' highlights the importance of new laboratory-based neurophysiological research for the treatment of newborn infant pain.