Search

Background: Electroencephalography (EEG) can be used in neonates to measure brain activity changes that are evoked by noxious events, such as clinically required immunisations, cannulation and heel lancing for blood tests. EEG provides an alternative approach to infer pain experience in infants compared with more commonly used behavioural and physiological pain assessments. Establishing the generalisability and construct validity of these measures will help corroborate the use of brain-derived outcomes to evaluate the efficacy of new or existing pharmacological and non-pharmacological methods to treat neonatal pain. This study aimed to test whether a measure of noxious-evoked EEG activity called the noxious neurodynamic response function (n-NRF), that was originally derived in a sample of term-aged infants at the Oxford John Radcliffe Hospital, UK, in 2017, can reliably distinguish noxious from non-noxious events in two independent datasets collected at University College London Hospital and at Royal Devon & Exeter Hospital. We aimed to reproduce three published results that use this measure to quantify noxious-evoked changes in brain activity. We used the n-NRF to quantify noxious-evoked brain activity to test (i) whether significantly larger noxious-evoked activity is recorded in response to a clinical heel lance compared to a non-noxious control heel lance procedure; (ii) whether the magnitude of the activity evoked by a noxious heel lance is equivalent in independent cohorts of infants; and (iii) whether the magnitude of the noxious-evoked brain activity increases with postmenstrual age (PMA) in premature infants up to 37 weeks PMA. Positive replication of these studies will build confidence in the use of the n-NRF as a valid and reliable pain-related outcome which could be used to evaluate analgesic efficacy in neonates. The protocol for this study was published following peer review (https://doi.org/10.17605/OSF.IO/ZY9MS)., Results: The n-NRF magnitude to a noxious heel lance stimulus was significantly greater than to a non-noxious control heel lance stimulus in both the UCL dataset (n = 60; mean difference .88; 95% confidence interval (CI) .64-1.13; p < .0001) and the Exeter dataset (n = 31; mean difference .31; 95% CI .02-.61; p = .02). The mean magnitude and 90% bootstrap confidence interval of the n-NRF evoked by the heel lance did not meet our pre-defined equivalence bounds of 1.0 ± .2 in either the UCL dataset (n = 72; mean magnitude 1.33; 90% bootstrapped CI 1.18-1.52) or the Exeter dataset (n = 35; mean magnitude .92, 90% bootstrapped CI .74-1.22). The magnitude of the n-NRF to the noxious stimulus was significantly positively correlated with PMA in infants up to 37 weeks PMA (n = 65; one-sided Pearson's R, adjusted for site: .24; 95% CI .06-1.00; p = .03)., Conclusions: We have reproduced in independent datasets the findings that the n-NRF response to a noxious stimulus is significantly greater than to a non-noxious stimulus, and that the noxious-evoked EEG response increases with PMA. The pre-defined equivalence bounds for the mean magnitude of the EEG response were not met, though this might be due to either inter-site differences such as the lack of calibration of devices between sites (a true negative) or underpowering (a false negative). This reproducibility study provides robust evidence that supports the use of the n-NRF as an objective outcome for clinical trials assessing acute nociception in neonates. Use of the n-NRF in this way has the potential to transform the way analgesic efficacy studies are performed., Competing Interests: Declaration of competing interest None., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Abstract: Parental involvement in neonatal comfort care is a core component of family-centred care. Yet, parents experience a range of positive and negative feelings when providing pain-relieving interventions for their infants. Parents of infants who participated in the Parental touch trial ( Petal ), a multicentre randomised controlled trial investigating the impact of gentle parental touch on neonatal pain, were asked to complete an anonymous survey. This survey aimed to (1) explore parent-reported motivations in deciding to participate in the Petal trial; (2) understand parent-reported experiences related to trial participation; (3) understand parents' willingness to participate in future studies; and (4) evaluate parent-reported feelings while they were delivering a gentle touch intervention either before or after a clinically necessary blood test. One hundred six parents (1 parent per infant) took part in the survey. Primary motivators for participation were altruistic. Parents most frequently reported that they wanted their child to take part in the research because it has a potential benefit to babies in the future and because they wanted to improve scientific understanding. Parents reported that providing gentle touch to their children during painful procedures was associated with positive emotions, such as feeling "useful" (64%) and "reassured" (53%). Furthermore, nearly all parents (98%) were pleased to have participated in the Petal trial and would consider, or maybe consider, participating in further research studies. These results underscore the importance of structuring trials around parental involvement and providing opportunities for parents to be involved in providing comfort to their infants during necessary painful clinical procedures., (Copyright © 2024 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the International Association for the Study of Pain.)

Background: Touch interventions such as massage and skin-to-skin contact relieve neonatal pain. The Parental touch trial (Petal) aimed to assess whether parental stroking of their baby before a clinically required heel lance, at a speed of approximately 3 cm/s to optimally activate C-tactile nerve fibres, provides effective pain relief., Methods: Petal is a multicentre, randomised, parallel-group interventional superiority trial conducted in the John Radcliffe Hospital (Oxford University Hospitals NHS Foundation Trust, Oxford, UK) and the Royal Devon and Exeter Hospital (Royal Devon University Healthcare NHS Foundation Trust, Exeter, UK). Neonates without neurological abnormalities who were born at 35 weeks gestational age or more and required a blood test via a heel lance in the first week of life were randomly assigned (1:1) to receive parental touch for 10 s either before (intervention group) or after (control group) the clinically required heel lance. Randomisation was managed at the Oxford site using a web-based minimisation algorithm with allocation concealment. The primary outcome measure was the magnitude of noxious-evoked brain activity in response to the heel lance measured with electroencephalography (EEG). Secondary outcome measures were Premature Infant Pain Profile-Revised (PIPP-R) score, development of tachycardia, and parental anxiety score. For all outcomes, the per-protocol effect was estimated via complier average causal effect analysis on the full analysis set. The trial is registered on ISRCTN (ISRCTN14135962) and ClinicalTrials.gov (NCT04901611)., Findings: Between Sept 1, 2021, and Feb 7, 2023, 159 parents were approached to participate in the study, and 112 neonates were included. 56 neonates were randomly assigned to the intervention group of parental stroking before the heel lance and 56 to the control group of parental stroking after the heel lance. The mean of the magnitude of the heel lance-evoked brain activity was 0·85 arbitrary units (a.u.; SD 0·70; n=39; a scaled magnitude of 1 a.u. represents the expected mean response to a heel lance in term-aged neonates) in the intervention group and 0·91 a.u. (SD 0·76; n=43) in the control group. Therefore, the primary outcome did not differ significantly between groups, with a mean difference of -0·11 a.u. (lower in intervention group; SD 0·77; 95% CI -0·42 to 0·20; p=0·38; n=82). No significant difference was observed across secondary outcomes. The PIPP-R difference in means was 1·10 (higher in intervention group, 95% CI -0·42 to 2·61; p=0·15; n=100); the odds ratio of becoming tachycardic was 2·08 (95% CI 0·46 to 9·46; p=0·34, n=105) in the intervention group with reference to the control group; and the difference in parental State-Trait Anxiety Inventory-State score was -0·44 (higher in control group; SD 6·85; 95% CI -2·91 to 2·02; p=0·72; n=106). One serious adverse event (desaturation) occurred in a neonate randomly assigned to the control group, which was not considered to be related to the study., Interpretation: Parental stroking delivered at an optimal speed to activate C-tactile fibres for a duration of 10 s before the painful procedure did not significantly change neonates' magnitude of pain-related brain activity, PIPP-R score, or development of tachycardia. The trial highlighted the challenge of translating an experimental researcher-led tactile intervention into a parent-led approach, and the value of involving parents in their baby's pain management., Funding: Wellcome Trust and Bliss., Competing Interests: Declaration of interests We declare no competing interests., (Copyright © 2024 The Author(s). Published by Elsevier Ltd. This is an Open Access article under the CC BY 4.0 license. Published by Elsevier Ltd.. All rights reserved.)

Introduction: Newborn infants routinely undergo minor painful procedures as part of postnatal care, with infants born sick or premature requiring a greater number of procedures. As pain in early life can have long-term neurodevelopmental consequences and lead to parental anxiety and future avoidance of interventions, effective pain management is essential. Non-pharmacological comfort measures such as breastfeeding, swaddling and sweet solutions are inconsistently implemented and are not always practical or effective in reducing the transmission of noxious input to the brain. Stroking of the skin can activate C-tactile fibres and reduce pain, and therefore could provide a simple and safe parent-led intervention for the management of pain. The trial aim is to determine whether parental touch prior to a painful clinical procedure provides effective pain relief in neonates., Methods and Analysis: This is a multicentre randomised controlled trial. A total of 112 neonates born at 35 weeks' gestation or more requiring a blood test in the first week of life will be recruited and randomised to receive parental stroking either preprocedure or postprocedure. We will record brain activity (EEG), cardiac and respiratory dynamics, oxygen saturation and facial expression to provide proxy pain outcome measures. The primary outcome will be the reduction of noxious-evoked brain activity in response to a heel lance. Secondary outcomes will be a reduction in clinical pain scores (Premature Infant Pain Profile-Revised), postprocedural tachycardia and parental anxiety., Ethics and Dissemination: The study has been approved by the London-South East Research Ethics Committee (ref: 21/LO/0523). The results will be widely disseminated through peer-reviewed publications, international conferences and via our partner neonatal charities Bliss and Supporting the Sick Newborn And their Parents (SSNAP). If the parental tactile intervention is effective, recommendations will be submitted via the National Health Service clinical guideline adoption process., Study Status: Commenced September 2021., Trial Registration Number: NCT04901611; 14 135 962., Competing Interests: Competing interests: None declared., (© Author(s) (or their employer(s)) 2022. Re-use permitted under CC BY. Published by BMJ.)

Infants who are born prematurely are at significant risk of apnoea. In addition to the short-term consequences such as hypoxia, apnoea of prematurity has been associated with long-term morbidity, including poor neurodevelopmental outcomes. Clinical trials have illustrated the importance of methylxanthine drugs, in particular caffeine, in reducing the risk of long term adverse neurodevelopmental outcomes. However, the extent to which apnoea is causative of this secondary neurodevelopmental delay or is just associated in a background of other sequelae of prematurity remains unclear. In this review, we first discuss the pathophysiology of apnoea of prematurity, previous studies investigating the relationship between apnoea and neurodevelopmental delay, and treatment of apnoea with caffeine therapy. We propose a need for better methods of measuring apnoea, along with improved understanding of the neonatal brain's response to consequent hypoxia. Only then can we start to disentangle the effects of apnoea on neurodevelopment in preterm infants. Moreover, by better identifying those infants who are at risk of apnoea, and neurodevelopmental delay, we can work toward a risk stratification system for these infants that is clinically actionable, for example, with doses of caffeine tailored to the individual. Optimising treatment of apnoea for individual infants will improve neonatal care and long-term outcomes for this population., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2021 Williamson, Poorun and Hartley.)

Objectives: Premature birth is associated with a wide range of complications in later life, including structural and functional neurological abnormalities and altered pain sensitivity. We investigated whether during anaesthesia premature-born children display different patterns of background EEG activity and exhibit increased responses to nociceptive stimuli., Methods: We examined background EEG and time-locked responses to clinical cannulation in 45 children (mean age (±SD) at study: 4.9(±3.0)years) under sevoflurane monoanaesthesia maintained at a steady-state end-tidal concentration of 2.5%. 15 were born prematurely (mean gestational age at birth: 29.2 ± 3.9 weeks) and 30 were age-matched term-born children., Results: Background levels of alpha and beta power were significantly lower in the premature-born children compared to term-born controls (p=0.048). Clinical cannulation evoked a significant increase in delta activity (p=0.032), which was not significantly different between the two groups (p=0.44)., Conclusions: The results indicate that whilst under anaesthesia premature-born children display different patterns of background brain activity compared to term-born children., Significance: As electrophysiological techniques are increasingly used by anaesthetists to gauge anaesthetic depth, differences in background levels of electrophysiological brain activity between premature and term-born children may be relevant when considering titration of anaesthetic dose., (Copyright © 2015 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Various aspects of social behavior are influenced by the highly conserved corticotrophin-releasing factor (CRF) family of peptides and receptors in the mammalian telencephalon. This study has mapped and compared the telencephalic distribution of the CRF receptors, CRF1 and CRF2 , and two of their ligands, CRF and urocortin 3, respectively, in African mole-rat species with diametrically opposed social behavior. Naked mole-rats live in large eusocial colonies that are characterized by exceptional levels of social cohesion, tolerance, and cooperation in burrowing, foraging, defense, and alloparental care for the offspring of the single reproductive female. Cape mole-rats are solitary; they tolerate conspecifics only fleetingly during the breeding season. The telencephalic sites at which the level of CRF1 binding in naked mole-rats exceeds that in Cape mole-rats include the basolateral amygdaloid nucleus, hippocampal CA3 subfield, and dentate gyrus; in contrast, the level is greater in Cape mole-rats in the shell of the nucleus accumbens and medial habenular nucleus. For CRF2 binding, the sites with a greater level in naked mole-rats include the basolateral amygdaloid nucleus and dentate gyrus, but the septohippocampal nucleus, lateral septal nuclei, amygdalostriatal transition area, bed nucleus of the stria terminalis, and medial habenular nucleus display a greater level in Cape mole-rats. The results are discussed with reference to neuroanatomical and behavioral studies of various species, including monogamous and promiscuous voles. By analogy with findings in those species, we speculate that the abundance of CRF1 binding in the nucleus accumbens of Cape mole-rats reflects their lack of affiliative behavior., (© 2015 Wiley Periodicals, Inc.)

Measuring infant pain is complicated by their inability to describe the experience. While nociceptive brain activity, reflex withdrawal and facial grimacing have been characterised, the relationship between these activity patterns has not been examined. As cortical and spinally mediated activity is developmentally regulated, it cannot be assumed that they are predictive of one another in the immature nervous system. Here, using a new experimental paradigm, we characterise the nociceptive-specific brain activity, spinal reflex withdrawal and behavioural activity following graded intensity noxious stimulation and clinical heel lancing in 30 term infants. We show that nociceptive-specific brain activity and nociceptive reflex withdrawal are graded with stimulus intensity (p < 0.001), significantly correlated (r = 0.53, p = 0.001) and elicited at an intensity that does not evoke changes in clinical pain scores (p = 0.55). The strong correlation between reflex withdrawal and nociceptive brain activity suggests that movement of the limb away from a noxious stimulus is a sensitive indication of nociceptive brain activity in term infants. This could underpin the development of new clinical pain assessment measures.

Limited understanding of infant pain has led to its lack of recognition in clinical practice. While the network of brain regions that encode the affective and sensory aspects of adult pain are well described, the brain structures involved in infant nociceptive processing are completely unknown, meaning we cannot infer anything about the nature of the infant pain experience. Using fMRI we identified the network of brain regions that are active following acute noxious stimulation in newborn infants, and compared the activity to that observed in adults. Significant infant brain activity was observed in 18 of the 20 active adult brain regions but not in the infant amygdala or orbitofrontal cortex. Brain regions that encode sensory and affective components of pain are active in infants, suggesting that the infant pain experience closely resembles that seen in adults. This highlights the importance of developing effective pain management strategies in this vulnerable population.

More than 235,000 children/year in the UK receive general anaesthesia, but it is unknown whether nociceptive stimuli alter cortical brain activity in anaesthetised children. Time-locked electroencephalogram (EEG) responses to experimental tactile stimuli, experimental noxious stimuli, and clinically required cannulation were examined in 51 children (ages 1-12 years) under sevoflurane monoanaesthesia. Based on a pilot study (n=12), we hypothesised that noxious stimulation in children receiving sevoflurane monoanaesthesia would evoke an increase in delta activity. This was tested in an independent sample of children (n=39), where a subset (n=11) had topical local anaesthetic applied prior to stimulation. A novel method of time-locking the stimuli to the EEG recording was developed using an event detection interface and high-speed camera. Clinical cannulation evoked a significant increase (34.2 ± 8.3%) in delta activity (P=0.042), without concomitant changes in heart rate or reflex withdrawal, which was not observed when local anaesthetic was applied (P=0.30). Experimental tactile (P=0.012) and noxious (P=0.0099) stimulation also evoked significant increases in delta activity, but the magnitude of the response was graded with stimulus intensity, with the greatest increase evoked by cannulation. We demonstrate that experimental and clinically essential noxious procedures, undertaken in anaesthetised children, alter the pattern of EEG activity, that this response can be inhibited by local anaesthetic, and that this measure is more sensitive than other physiological indicators of nociception. This technique provides the possibility that sensitivity to noxious stimuli during anaesthesia could be investigated in other clinical populations., (Copyright © 2014 The Authors. Published by Elsevier B.V. All rights reserved.)

African mole-rats provide a unique taxonomic group for investigating the evolution and neurobiology of sociality. The two species investigated here display extreme differences in social organization and reproductive strategy. Naked mole-rats (NMRs) live in colonies, dominated by a queen and her consorts; most members remain nonreproductive throughout life but cooperate in burrowing, foraging, and caring for pups, for which they are not biological parents (alloparenting). In contrast, Cape mole-rats (CMRs) are solitary and intolerant of conspecifics, except during fleeting seasonal copulation or minimal maternal behavior. Research on other mammals suggests that oxytocin receptors at various telencephalic sites regulate social recognition, monogamous pair bonding, and maternal/allomaternal behavior. Current paradigms in this field derive from monogamous and polygamous species of New World voles, which are evolutionarily remote from Old World mole-rats. The present findings indicate that NMRs exhibit a considerably greater level of oxytocin receptor (OTR) binding than CMRs in the: nucleus accumbens; indusium griseum; central, medial, and cortical amygdaloid nuclei; bed nucleus of the stria terminalis; and CA1 hippocampal subfield. In contrast, OTR binding in the piriform cortex is intense in CMRs but undetectable in NMRs. We speculate that the abundance of OTR binding and oxytocin-neurophysin-immunoreactive processes in the nucleus accumbens of NMRs reflects their sociality, alloparenting behavior, and potential for reproductive attachments. In contrast, the paucity of oxytocin and its receptors at this site in CMRs may reflect a paucity of prosocial behaviors. Whether similarities in OTR expression between eusocial mole-rats and monogamous voles are due to gene conservation or convergent evolution remains to be determined., ((c) 2009 Wiley-Liss, Inc.)

Changes in metabolic state, such as those induced by fasting, have profound effects on reproduction. In rats, the time-course over which fasting inhibits luteinising hormone (LH) release is reduced to 48 h by the presence of oestradiol-17beta (E(2)). Hypothalamic kisspeptin plays a key role in mediating the actions of E(2) on gonadotrophin-releasing hormone (GnRH) neurones, and thereby promotes LH release. KiSS-1-expressing neurones are found in the anteroventral periventricular nucleus (AVPV) and arcuate nucleus (ARC). Extensive evidence implicates the AVPV in GnRH release and the ARC in energy balance. The latter nucleus also contains neurones that express neuropeptide Y (NPY), an orexigenic peptide implicated in GnRH control. To elucidate the involvement of kisspeptin and/or NPY in hypothalamic responses to fasting, their expression was quantified by in situ hybridisation histochemistry in ovariectomised rats, with or without E(2) replacement, before and after 48 h of fasting. In the presence of E(2), but not in its absence, the fasting suppressed plasma LH. In the AVPV, the low level of KiSS-1 expression found in the absence of E(2) was unaffected by fasting. By contrast, the elevated level found in the presence of E(2) was suppressed by fasting. Independent of E(2), fasting had no effect on KiSS-1 expression in the ARC, but increased NPY expression at that site. The present study has identified the AVPV as a site at which KiSS-1 expression can be influenced by fasting. The results suggest that inhibition of KiSS-1 expression in the AVPV may be a significant factor in restraining the gonadotrophic axis in response to negative energy balance in the presence of oestrogen. The extent to which the concurrent rise in NPY expression in the ARC may contribute to the suppression of LH release by influencing AVPV kisspeptin neurones, directly or indirectly, or by actions independent of kisspeptin, remains to be established.