Enhancing sensory experiences for very preterm infants in the NICU: an integrative review

Towards an architecture of flexibility

OBJECTIVE

Our objective was to explore the case for adoption of flexibility as a core value in the design process for Neonatal Intensive Care Units (NICUs).

METHODS

Guidelines for NICU design and care of NICU patients and families were examined to identify opportunities for building flexibility into NICU design to optimize function and experience.

RESULTS

Benefits of building flexibility into NICU design included the ability for units to adapt quickly and economically to unpredictable events and demographic changes. Further, by centering family presence as a design necessity, NICUs may better protect families from experiencing additional harm due to separation and interruption of restorative activities. We were able to highlight several examples of current NICUs, which have successfully adopted flexible design and operational models to provide optimal levels of clinical and family-centered care.

CONCLUSION

By intentionally incorporating flexibility into the design of an NICU, infants, families, and healthcare providers can be provided with an environment that can adapt to shifting needs to optimally support unit function and clinical outcomes.

Early neurobehavior at 30 weeks postmenstrual age is related to outcome at term equivalent age

AIMS

To determine 1) the relationship between infant medical factors and early neurobehavior, and 2) the relationship between early neurobehavior at 30 weeks postmenstrual age (PMA) and neurobehavior at term equivalent age.

STUDY DESIGN

In this prospective longitudinal study, 88 very preterm infants born ≤30 weeks estimated gestational age (EGA) had neurobehavioral assessments at 30 weeks PMA using the Premie-Neuro and at term equivalent age using the NICU Network Neurobehavioral Scale (NNNS) and Hammersmith Neonatal Neurological Evaluation (HNNE).

RESULTS

Lower Premie-Neuro scores at 30 weeks PMA were related to being more immature at birth (p = 0.01; β = 3.87); the presence of patent ductus arteriosus (PDA; p < 0.01; β = -16.50) and cerebral injury (p < 0.01; β = -20.46); and prolonged exposure to oxygen therapy (p < 0.01; β = -0.01), endotracheal intubation (p < 0.01; β = -0.23), and total parenteral nutrition (p < 0.01; β = -0.35). After controlling for EGA, PDA, and number of days of endotracheal intubation, lower Premie-Neuro scores at 30 weeks PMA were independently related to lower total HNNE scores at term (p < 0.01; β = 0.12) and worse outcome on the NNNS with poorer quality of movement (p < 0.01; β = 0.02) and more stress (p < 0.01; ß = -0.004), asymmetry (p = 0.01; β = -0.04), excitability (p < 0.01; β = -0.05) and suboptimal reflexes (p < 0.01; ß = -0.06).

CONCLUSION

Medical factors were associated with early neurobehavioral performance at 30 weeks PMA. Early neurobehavior at 30 weeks PMA was a good marker of adverse neurobehavior at NICU discharge.

Music Therapy for Preterm Infants and Their Parents: A Cluster-Randomized Controlled Trial Protocol

Music therapy (MT) interventions and skin-to-skin care (SSC) both aim to address the varied needs of preterm infants, including sensory regulation and stress reduction, inclusion of parents in their infant's care, support of parents' emotional state, and enhancing the parent-infant attachment process. Few studies have investigated the combination of both modalities through randomized controlled trials. Evidence of longer-term effects is missing. This article presents a study protocol that will investigate the effects of combined family-centered MT intervention and SSC on preterm-infants' autonomic nervous system (ANS) stability, parental anxiety levels, and parent-infant attachment quality. 12 clusters with a total of 72 preterm infants, with their parents, will be randomized to one of two conditions: MT combined with SSC or SSC alone. Each parent-infant dyad will participate in 3 sessions (2 in the hospital and a 3-month follow-up). The primary outcome of preterm infants' ANS stability will be measured by the high frequency power of their heart rate variability. Secondary outcomes will be physiological measures and behavioral states in infants and anxiety and attachment levels of parents. This trial will provide important, evidence-based knowledge on the use of the "First Sounds: Rhythm, Breath, and Lullaby" model of MT in neonatal care, through an intervention that is in line with the Newborn Individualized Developmental Care and Assessment Program model for supportive developmental care of preterm infants and their parents. Ethical approval (no. 0283-15) was granted from the local Institutional Review Board in April 2017. This trial is registered in ClinicalTrials.gov, NCT03023267.

Establishing a Foundation for Optimal Feeding Outcomes in the NICU

Many infants in the NICU experience difficulties with oral feeding, which contribute to prolonged length of stay. Oral feeding is a complex task involving sensorimotor functioning of the face, mouth, and larynx, as well as coordination of sucking, swallowing, and breathing. The care provided in the NICU starting at birth sets the stage for future oral feeding. The purpose of this article is to describe strategies that will establish a positive foundation to support optimal oral feeding. Nurses can use these strategies to protect newborns from noxious stimuli and promote positive auditory, tactile, gustatory, and olfactory experiences to optimize neurodevelopment for the complex task of feeding.

A pilot study demonstrating the impact of the supporting and enhancing NICU sensory experiences (SENSE) program on the mother and infant

AIM

To explore differences in maternal mental health and infant neurobehavioral outcome among infants who received and did not receive the Supporting and Enhancing NICU Sensory Experiences (SENSE) program.

STUDY DESIGN

Eighty preterm infants (50 receiving standard-of-care and 30 receiving the SENSE program) born ≤32 weeks gestation were enrolled within the first week of life in a prospective quasi-experimental design, using a historical control group for comparison. Standard-of-care consisted of tactile (skin-to-skin, touch, holding) and olfactory (scent cloth, close maternal contact) interventions as determined to be appropriate by health care professionals and parents. The SENSE group received specific doses of tactile (skin-to-skin care, holding, massage, touch), auditory (human speech, music), olfactory (scent cloth, close maternal contact), kinesthetic/vestibular (movement, rocking/transfers), and visual (dim or cycled light) exposures, based on the infant's postmenstrual age and tailored to medical status and infant cues according to the SENSE program. The SENSE program includes the intentional delivery of positive, age-appropriate sensory exposures by parents (or a sensory support team, when parents are unavailable) each day of NICU hospitalization. Infant neurobehavioral outcome, as well as maternal mental health and confidence, were assessed prior to NICU discharge, using standardized measures.

RESULTS

Seventy-three infants were included in the final analysis. Mothers whose infants received the SENSE program demonstrated higher scores on the Maternal Confidence Questionnaire (p = 0.01). Infants who received the SENSE program demonstrated less asymmetry on the NICU Network Neurobehavioral Scale (p = 0.02; mean difference 0.9) and higher scores on the Hammersmith Neonatal Neurological Evaluation (p < 0.001; mean difference 4.8).

DISCUSSION

Preliminary evidence demonstrates improvements in maternal confidence and infant neurobehavioral performance following SENSE implementation.

Neonatal intensive care unit incubators reduce language and noise levels more than the womb

OBJECTIVE

To assess the sound reducing characteristics of modern incubators in the neonatal intensive care unit (NICU) and to better characterize auditory and language exposures for NICU infants.

STUDY DESIGN

Sound frequency spectral analysis was conducted on language and noise audio acquired simultaneously inside and outside incubators located in the NICU.

RESULTS

Sound transmission into the incubators was nonuniform. Very low-frequency sounds (<100 Hz) were unattenuated or even slightly amplified inside the incubators. Maximal reduction was observed for low-to-mid frequencies (300-600 Hz) and high frequencies (>2000 Hz), which convey important language information.

CONCLUSIONS

Sound reductions observed across NICU incubator walls are more severe than those reported for sound transmission into the intrauterine environment, particularly for midrange frequencies that are important for language. Although incubator walls may serve as a protection against noxious noise levels, these findings reveal a potentially detrimental effect on language exposure for infants inside a NICU incubator.

Pathophysiology of Gastroesophageal Reflux Disease in Infants and Nonpharmacologic Strategies for Symptom Management

Gastroesophageal reflux is common in young infants, particularly those born prematurely or with a history of medical complexity. The most recent clinical practice guidelines recommend the use of nonpharmacologic management strategies because of concerns about the safety of acid-reducing medications and a lack of evidence of their effectiveness. Our purpose in this article is to holistically review the pathophysiology of gastroesophageal reflux disease, identify symptom management targets, and describe nonpharmacologic strategies that nurses can implement and/or teach to parents to manage symptoms of gastroesophageal reflux. Strategies targeting stress, dysbiosis, food intolerances, feeding difficulties, and positioning are discussed. Nurses can work with families to identify factors contributing to gastroesophageal reflux disease and determine individualized strategies that can be used in lieu of, or in addition to, medication.

Mechanisms of Timing, Timbre, Repertoire, and Entrainment in Neuroplasticity: Mutual Interplay in Neonatal Development

Neonatal brain development relies on a combination of critical factors inclusive of genetic predisposition, attachment, and the conditions of the pre and postneonatal environment. The status of the infant’s developing brain in its most vulnerable state and the impact that physiological elements of music, silences and sounds may make in the earliest stages of brain development can enhance vitality. However, little attention has been focused on the integral aspects of the music itself. This article will support research that has hypothesized conditions of music therapeutic applications in an effort to further validate models of neurobehavioral care that have optimized conditions for growth, inclusive of recommendations leading toward the enhancement of self-regulatory behaviors.

Effects of Early Intervention on Visual Function in Preterm Infants: A Randomized Controlled Trial

Objectives: To determine the effectiveness of an early intervention program in enhancing visual function in very preterm infants. Methods: We conducted a RCT. We included preterm infants born between 25⁺⁰ and 29⁺⁶ weeks of gestational age (GA), without severe morbidities, and their families. Infants were randomized to either receive Standard Care (SC) or Early Intervention (EI). SC, according to NICU protocols, included Kangaroo Mother Care and minimal handling. EI included, in addition to routine care, parental training according to the PremieStart program, and multisensory stimulation (infant massage and visual interaction) performed by parents. Visual function was assessed at term equivalent age (TEA) using a prevalidated battery evaluating ocular spontaneous motility, ability to fix and follow a target, reaction to color, stripes discrimination and visual attention at distance. Results: Seventy preterm (EI n = 34, SC n = 36) infants were enrolled. Thirteen were excluded according to protocol. Fifty-seven infants (EI = 27, SC = 30) were assessed at TEA. The two groups were comparable for parental and infant characteristics. In total, 59% of infants in the EI group achieved the highest score in all the nine assessed items compared to 17% in the SC group (p = 0.001): all infants in both groups showed complete maturation in four items, but EI infants showed more mature findings in the other five items (ocular motility both spontaneous and with target, tracking arc, stripes discrimination and attention at distance). Conclusions: Our results suggest that EI has a positive effect on visual function maturation in preterm infants at TEA. Trial Registration: clinicalTrial.gov (NCT02983513).

Early vocal contact and music in the NICU: new insights into preventive interventions

It is now clearly established that the environment and the sensory stimuli, particularly during the perinatal period, have an impact on infant's development. During the last trimester of gestation, activity-dependent plasticity shapes the fetal brain, and prematurity has been shown to alter the typical developmental trajectories. In this delicate period, preventive interventions aiming at modulating these developmental trajectories through activity-inducing interventions are currently underway to be tested. The purpose of this review paper is to describe the potentialities of early vocal contact and music on the preterm infant's brain development, and their potential beneficial effect on early development. Scientific evidence supports a behavioral orientation of the newborn to organized sounds, such as those of voice and music, and recent neuroimaging studies further confirm full cerebral processing of music as multisensory stimuli. However, the impact of long-term effects of music exposure and early vocal contact on preterm infants' long-term neurodevelopment needs be further investigated. To conclude, it is necessary to establish the neuroscientific bases of the early perception and the long-term effects of music and early vocal contact on the premature newborns' development. Scientific projects are currently on the way to fill this gap in knowledge.

Multimodal Neurologic Enhancement Improves Preterm Infants' Developmental Outcomes: A Longitudinal Pilot Study

PURPOSE

The purpose of this study was to identify the long-term developmental effects of a NICU music therapy intervention, Multimodal Neurologic Enhancement, provided to preterm infants in the NICU.

DESIGN

Prospective randomized controlled study with one control group and one experimental group.

SAMPLE

Participants were medically stable preterm infants with a birth age of 31 and 6/7 weeks or less, admitted to a level-III NICU. A total of 84 participants were enrolled, and 48 completed the study.

MAIN OUTCOME VARIABLE

Post-discharge developmental scores on the Mullen Scales of Early Learning: AGS Edition.

RESULTS

The experimental group performed significantly better than the control group on the Visual Reception and Early Learning Composite scores.

Individualised developmental care for babies and parents in the NICU: Evidence-based best practice guideline recommendations

Advances in neonatal care have improved survival of premature and critically ill infants; and while rates of some long-term neurodevelopmental problems in survivors have improved, such as cerebral palsy, there are others such as learning and behavioural difficulties that have not. The goal of improving long term neurodevelopmental morbidity has led to an increased focus on improving developmental care not only in neonatal long term follow- up clinics but within the NICU itself to capture the period of earliest brain neuroplasticity. The application of a systematic approach to improve practice is considered the most effective strategy for implementing neuroprotective developmentally supportive care. The content of this paper incorporates evidence-based systematic reviews to guide clinicians in the application of developmentally supportive interventions.

Parent psychological wellbeing in a single-family room versus an open bay neonatal intensive care unit

Background

Studies of parents’ psychological well-being in single-family rooms in neonatal intensive care units have shown conflicting results.

Aims

To compare emotional distress in the form of depression, anxiety, stress and attachment scores among parents of very preterm infants cared for in a single-family rooms unit vs an open bay unit.

Study design

Prospective survey design.

Subject

Parents (132) of 77 infants born at 28 0/7–32 0/7 weeks of gestation in the two units.

Outcome measures

Duration of parental presence was recorded. Scores for depression (The Edinburgh Postnatal Depression Scale), anxiety (The State–Trait–Anxiety Inventory, Short Form Y), stress (The Parent Stressor Scale: neonatal intensive care unit questionnaire and The Parenting Stress Index—short form) and attachment (Maternal Postnatal Attachment Scale) measured 14 days after delivery, at discharge, expected term date and four months post-term.

Results

Parents were present 21 hours/day in the single-family room unit vs 7 hours/day in the Open bay unit. Ninety-three percent of the fathers in the single-family rooms unit were present more than 12 hours per day during the first week. Mothers in the single-family rooms had a significantly lower depression score -1.9 (95% CI: -3.6, -0.1) points from birth to four months corrected age compared to mothers in the Open bay unit, and 14% vs 52% scored above a cut-off point considered being at high risk for depression (p<0.005). Both mothers and fathers in the single-family rooms reported significantly lower stress levels during hospitalization. There were no differences between the groups for anxiety, stress or attachment scores after discharge.

Conclusion

The lower depression scores by the mothers and lower parental stress scores during hospitalization for both parents supports that single-family rooms care contribute to parents’ psychological wellbeing.

Health Care Professionals' Perceptions about Sensory-Based Interventions in the NICU

OBJECTIVE

The main objective of this article is to define perceptions of health care professionals regarding current use of sensory-based interventions in the neonatal intensive care unit (NICU).

STUDY DESIGN

A multidisciplinary group of NICU health care professionals (n = 108) defined the types of sensory-based interventions used in their NICU, the postmenstrual age (PMA) sensory-based interventions are administered, conditions under which sensory-based interventions are used, and personnel who administer sensory-based interventions.

RESULTS

The most commonly reported tactile intervention was infant holding (88% of respondents), the most common auditory intervention was recorded music/singing (69% of respondents), the most common kinesthetic intervention was occupational and physical therapy (85% of respondents), and the most common vestibular intervention was infant swings (86% of respondents). Tactile interventions were initiated most often at 24 to 26 weeks PMA (74% of respondents), auditory interventions at 30 to 32 weeks (60% of respondents), kinesthetic interventions at 30 to 32 weeks (76% of respondents), vestibular interventions at 33 to 34 weeks (86% of respondents), and visual interventions at 32 to 36 weeks (72% of respondents). Conditions under which sensory-based interventions were administered, and personnel who provided them, varied across settings.

CONCLUSION

Varied use of sensory-based interventions in the NICU were reported. While this study was limited by biased sampling and the identification of health care professionals' perceptions but not real-world practice, this information can be used to build a comprehensive approach to positive sensory exposures in the NICU.

Osteopathic Manipulation Treatment Improves Cerebro-splanchnic Oximetry in Late Preterm Infants

Background: To evaluate the effectiveness/side-effects of osteopathic manipulation treatment (OMT) performed on the 7th post-natal day, on cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in late preterm (LP) infants by using near infrared spectroscopy (NIRS). Methods: Observational pretest-test study consisting in a cohort of 18 LPs who received OMT on the 7th post-natal day. NIRS monitoring was performed at three different time-points: 30 min before (T0), (30 min during (T1) and 30 min after OMT (T2). We evaluated the effects of OMT on the following NIRS parameters: cerebral (c), splanchnic (s) regional oximetry (rSO2), cerebro-splanchnic fractional tissue oxygen extraction (FTOE) and hemodynamic redistribution (CSOR). Results: crSO2 and cFTOE significantly (P < 0.001) improved at T0-T2; srSO2 significantly (P < 0.001) decreased and sFTOE increased at T0-T1. Furthermore, srSO2 and sFTOE significantly improved at T1-T2. Finally, CSOR significantly (P < 0.05) increased at T0-T2. Conclusions: The present data show that OMT enhances cerebro-splanchnic oximetry, tissue activation and hemodynamic redistribution in the absence of any adverse clinical or laboratory pattern. The results indicate the usefulness of further randomized studies in wider populations comparing the effectiveness of OMT with standard rehabilitation programs.

Dysmaturation of Premature Brain: Importance, Cellular Mechanisms, and Potential Interventions

Prematurity, especially preterm birth (less than 32 weeks' gestation), is common and associated with high rates of both survival and neurodevelopmental disability, especially apparent in cognitive spheres. The neuropathological substrate of this disability is now recognized to be related to a variety of dysmaturational disturbances of the brain. These disturbances follow initial brain injury, particularly cerebral white matter injury, and involve many of the extraordinary array of developmental events active in cerebral white and gray matter structures during the premature period. This review delineates these developmental events and the dysmaturational disturbances that occur in premature infants. The cellular mechanisms involved in the genesis of the dysmaturation are emphasized, with particular focus on the preoligodendrocyte. A central role for the diffusely distributed activated microglia and reactive astrocytes in the dysmaturation is now apparent. As these dysmaturational cellular mechanisms appear to occur over a relatively long time window, interventions to prevent or ameliorate the dysmaturation, that is, neurorestorative interventions, seem possible. Such interventions include pharmacologic agents, especially erythropoietin, and particular attention has also been paid to such nutritional factors as quality and source of milk, breastfeeding, polyunsaturated fatty acids, iron, and zinc. Recent studies also suggest a potent role for interventions directed at various experiential factors in the neonatal period and infancy, i.e., provision of optimal auditory and visual exposures, minimization of pain and stress, and a variety of other means of environmental behavioral enrichment, in enhancing brain development.

Supporting and enhancing NICU sensory experiences (SENSE): Defining developmentally-appropriate sensory exposures for high-risk infants

INTRODUCTION

There is evidence to support the use of positive sensory exposures (music, touch, skin-to-skin) with preterm infants in the neonatal intensive care unit (NICU), but strategies to improve their consistent use are lacking. The Supporting and Enhancing NICU Sensory Experiences (SENSE) program was developed to promote consistent, age-appropriate, responsive, and evidence-based positive sensory exposures for the preterm infant every day of NICU hospitalization.

METHODS

A systematic and rigorous process of development of the SENSE program included an integrative review of evidence on sensory exposures in the NICU, stakeholder feedback, expert opinion, and focus groups.

RESULTS

SENSE implementation materials consist of parent education materials, tailored doses of sensory exposures for each postmenstrual age, an infant assessment of tolerance, bedside logs and implementation considerations for integrating the SENSE program into the NICU.

DISCUSSION

Research is needed to evaluate the SENSE program as an implementation strategy and to assess its impact on parent and infant outcomes.

Music in premature infants enhances high-level cognitive brain networks

Preterm babies are cared for in neonatal intensive care units (NICU), which are busy places with a lot of mechanical noise increasingly recognized to disrupt normal brain development. NICUs therefore invest in developmental care procedures, with music for example, but neurobiological evidence for these interventions is missing. We present results from a clinical trial to study the effects of a music intervention on preterm infants’ brain development. Based on resting-state fMRI, we provide evidence that music enhanced connectivity in a brain circuitry involving the salience network with regions implicated in sensory and higher-order cognitive functions, previously found to be altered in preterm infants. To our knowledge, this study is unique in observing an impact of music on brain development in preterm newborns.

Neonatal intensive care units are willing to apply environmental enrichment via music for preterm newborns. However, no evidence of an effect of music on preterm brain development has been reported to date. Using resting-state fMRI, we characterized a circuitry of interest consisting of three network modules interconnected by the salience network that displays reduced network coupling in preterm compared with full-term newborns. Interestingly, preterm infants exposed to music in the neonatal intensive care units have significantly increased coupling between brain networks previously shown to be decreased in premature infants: the salience network with the superior frontal, auditory, and sensorimotor networks, and the salience network with the thalamus and precuneus networks. Therefore, music exposure leads to functional brain architectures that are more similar to those of full-term newborns, providing evidence for a beneficial effect of music on the preterm brain.

Resilience priming: Translational models for understanding resiliency and adaptation to early life adversity

Despite the increasing attention to early life adversity and its long-term consequences on health, behavior, and the etiology of neurodevelopmental disorders, our understanding of the adaptations and interventions that promote resiliency and rescue against such insults are underexplored. Specifically, investigations of the perinatal period often focus on negative events/outcomes. In contrast, positive experiences (i.e. enrichment/parental care//healthy nutrition) favorably influence development of the nervous and endocrine systems. Moreover, some stressors result in adaptations and demonstrations of later-life resiliency. This review explores the underlying mechanisms of neuroplasticity that follow some of these early life experiences and translates them into ideas for interventions in pediatric settings. The emerging role of the gut microbiome in mediating stress susceptibility is also discussed. Since many negative outcomes of early experiences are known, it is time to identify mechanisms and mediators that promote resiliency against them. These range from enrichment, quality parental care, dietary interventions and those that target the gut microbiota.

Neuroprocessing Mechanisms of Music during Fetal and Neonatal Development: A Role in Neuroplasticity and Neurodevelopment

The primary aim of this viewpoint article is to examine recent literature on fetal and neonatal processing of music. In particular, we examine the behavioral, neurophysiological, and neuroimaging literature describing fetal and neonatal music perception and processing to the first days of term equivalent life. Secondly, in light of the recent systematic reviews published on this topic, we discuss the impact of music interventions on the potential neuroplasticity pathways through which the early exposure to music, live or recorded, may impact the fetal, preterm, and full-term infant brain. We conclude with recommendations for music stimuli selection and its role within the framework of early socioemotional development and environmental enrichment.

Randomized controlled trial protocol to improve multisensory neural processing, language and motor outcomes in preterm infants

BACKGROUND

Premature infants are at risk for abnormal sensory development due to brain immaturity at birth and atypical early sensory experiences in the Neonatal Intensive Care Unit. This altered sensory development can have downstream effects on other more complex developmental processes. There are currently no interventions that address rehabilitation of sensory function in the neonatal period.

METHODS

This study is a randomized controlled trial of preterm infants enrolled at 32-36 weeks postmenstrual age to either standard care or standard care plus multisensory intervention in order to study the effect of multisensory intervention as compared to standard care alone. The study population will consist of 100 preterm infants in each group (total n = 200). Both groups will receive standard care, consisting of non-contingent recorded parent's voice and skin-to-skin by parent. The multisensory group will also receive contemporaneous holding and light pressure containment for tactile stimulation, playing of the mother's voice contingent on the infant's pacifier sucking for auditory stimulation, exposure to a parent-scented cloth for olfactory stimulation, and exposure to carefully regulated therapist breathing that is mindful and responsive to the child's condition for vestibular stimulation. The primary outcome is a brain-based measure of multisensory processing, measured using time locked-EEG. Secondary outcomes include sensory adaptation, tactile processing, speech sound differentiation, motor and language function, measured at one and two years corrected gestational age.

DISCUSSION

This is the first randomized controlled trial of a multisensory intervention using brain-based measurements in order to explain the causal effects of the multisensory intervention on neural processing changes to mediate neurodevelopmental outcomes in former preterm infants. In addition to contributing a critical link in our understanding of these processes, the protocolized multisensory intervention in this study is therapist administered, parent supported and leverages simple technology. Thus, this multisensory intervention has the potential to be widely implemented in various NICU settings, with the opportunity to potentially improve neurodevelopment of premature infants.

TRIAL REGISTRATION

NIH Clinical Trials ( clinicaltrials.gov ): NCT03232931 . Registered July 2017.

Preterm infant showed better object handling skills in a neonatal intensive care unit during silence than with a recorded female voice

AIM

This study compared whether preterm infants showed better tactile abilities during silence or when they heard a prerecorded female voice at different intensities.

METHODS

We studied 74 preterm infants of 28-35 weeks' postconceptional age who were admitted to a French neonatal intensive care unit from 2014 to 2017. They were presented with wooden objects, one smooth and one angled, at various points during silence (n = 26) or while listening to a female voice at +5 (n = 24) or +15 decibels (n = 24) inside their incubator. We compared the conditions to see if there was any difference in how the infants handled the objects and also compared familiar and unfamiliar objects.

RESULTS

The preterm infants showed better handling skills and only displayed effective discrimination, during silence. We found that 27.1% of the infants exposed to female voices failed to get habituated to the object, compared to 7.7% in the silence condition (p < 0.05) and success during the voice conditions required more trials (6.1 vs. 5.3) than the silence condition (p = 0.05). The different voice intensities made no difference.

CONCLUSION

Being exposed to a female voice had a negative impact on preterm infants' tactile sensory learning, regardless of its intensity.

Late preterm births: New insights from neonatal neuroimaging and neurobehaviour

With increasing evidence of neurodevelopmental problems faced by late preterm children, there is a need to explore possible underlying brain structural changes. The use of brain magnetic resonance imaging has provided insights of smaller and less mature brains in infants born late preterm, associated with developmental delay at 2 years. Another useful tool in the newborn period is neurobehavioural assessment, which has also been shown to be suboptimal in late preterm infants compared with tern infants. Suboptimal neurobehaviour is also associated with poorer 2-year neurodevelopment in late preterm infants. More research into these tools will provide a better understanding of the underlying processes of developmental deficits of late preterm children. The value of their role in clinical care remains to be determined.

Early-life growth of preterm infants and its impact on neurodevelopment

BACKGROUND

Increasing numbers of preterm-born children survive nowadays, and improving long-term health and neurodevelopment is becoming more important. Early-life growth has been linked to neurodevelopmental outcomes. We aimed to study whether this association has changed with time.

METHODS

We studied two cohorts of preterm-born children (gestational age ≤32 weeks and/or birth weight ≤1500 g) from 1983 (n = 708) and 2003-2006 (n = 138), respectively. We distinguished four early-life growth patterns at 3 months corrected age: appropriate for gestational age (AGA) with or without growth restriction (AGA GR+/AGA GR-), and small for gestational age (SGA) with or without catch-up growth (SGA CUG+/SGA CUG-). Intelligence quotient (IQ), neuromotor function, and behavior were assessed at ages 19 and 8 years, respectively, for the cohorts.

RESULTS

In the 2003-2006 cohort, less children had early-life GR. In both cohorts, SGA CUG- subjects had unfavorable growth trajectories and neurodevelopmental outcomes (IQ β -6.5, 95% confidence interval (CI) -9.8; -3.2, P < 0.001; neuromotor score β -1.9%, 95% CI -3.2; -0.6, P = 0.005), while SGA CUG+ subjects were comparable to adequately grown subjects.

CONCLUSION

Although the incidence of adverse growth patterns decreased between the cohorts, possibly indicating improvements in care over time, the impact of these growth patterns on neurodevelopmental outcomes was not significantly different. Achieving adequate early-life growth may be crucial for improving neurodevelopmental outcomes, especially for preterms born SGA.

Targeted sensory enrichment interventions protect against behavioral and neuroendocrine consequences of early life stress

Both basic and clinical research support the use of tactile stimulation to rescue several neurobiobehavioral consequences that follow early life stress. Here, using a translational rodent model of the neonatal intensive care unit (NICU), we tested the individual prophylactic potential of a variety of sensory interventions including tactile (brushing pups with a paint brush to mimic maternal licking), auditory (a simulated lactating rat dam heart beat), and olfactory (a series of aroma therapy scents) stimulation. The NICU model was developed to mimic not only the reduced parental contact that sick infants receive (by isolating rat pups from their litters), but also the nosocomial infections and medical manipulations associated with this experience (by utilizing a dual lipopolysaccharide injection schedule). Each of the neurobiobehavioral consequences observed were dissociable between isolation and inflammation, or required a combined presentation ('two hits') of the neonatal stressors. Sprague-Dawley rats exposed to these early life stressors presented with sex-specific disruptions in both separation-induced ultrasonic vocalization (USV) distress calls (males & females) and juvenile social play USVs (males only). All three sensory enhancement interventions were associated with the rescue of potentiated distress calls while olfactory stimulation was protective of social vocalizations. Female rats exposed to early life stress experienced precocious puberty and shifts in the hypothalamic GnRh axis; sensory enrichment counter-acted the advanced pubertal onset. Animals that underwent the NICU protocol also displayed maturational acceleration in terms of the loss of the rooting reflex in addition to hyperalgesia, a reduced preference for a novel conspecific, blunted basal plasma corticosterone and reduced hippocampal glucocorticoid receptor expression. These alterations closely simulated the clinical effects of early life adversity in terms of disruptions in the hypothalamic pituitary "stress" axis, social communication and engagement, tactile system processing, and accelerated maturation. Moreover, sensory enrichment attenuated many of these behavioral and neurophysiological alterations, and even slowed maturation. Overall, this supports the translatability of our novel rodent model and its potential utility in understanding how brain maturation and quality of early life experiences may interact to shape the integrity of stress and sensory system development. Future work must determine the appropriate modalities and parameters (e.g. patterning, timing) for effective sensory enrichment interventions.

Human interaction in the NICU and its association with outcomes on the Brief Infant-Toddler Social and Emotional Assessment (BITSEA)

BACKGROUND

Extremely preterm infants represent one of the highest risk categories for impairments in social competence. Few studies have explored the impact of the neonatal intensive care unit (NICU) environment on social development. However, none have specifically analyzed the effects of the care structure the infant receives during hospitalization on later social competence indicators.

OBJECTIVE

To identify associations between the care structures received by extremely preterm infants in the NICU and scores on the Brief Infant-Toddler Social and Emotional Assessment (BITSEA) post-discharge.

PARTICIPANTS

50 extremely preterm infants (mean gestational age: 25 weeks during hospitalization; mean chronological age during follow-up assessment: 2 years, 4 months).

METHODS

A secondary analysis of BITSEA data was performed exploring its relation to care structure data we extracted from electronic medical records (i.e., how much time infants were engaged in human interaction during their first thirty days of hospitalization and what types of interaction they were exposed to).

RESULTS

Extremely preterm infants spend a considerable amount of time alone during hospitalization (80%) with nursing care comprising the majority of human interaction. Infants who experienced greater human interaction scored significantly higher on the Social Competence (p = 0.01) and lower on the Dysregulation (p = 0.03) BITSEA subscales.

CONCLUSION

Human interaction and isolation in the NICU is associated with social competence and dysregulation outcomes in extremely preterm infants. Further research is needed to understand how various NICU care structures including centralized nursing teams, parental skin-to-skin care, and early therapy may synergistically play a positive role in developing social competence.

Programming of the Adult HPA Axis After Neonatal Separation and Environmental Stress in Male and Female Rats

Maternal separation, hypoxia, and hypothermia are common stressors in the premature neonate. Using our rat model of human prematurity, we evaluated sexual dimorphisms in the long-term effects of these neonatal stressors on behavior of the hypothalamic-pituitary-adrenal (HPA) axis in adult rats. Neonatal rats were exposed daily on postnatal days 2 to 6 to maternal separation with normoxia, with hypoxia allowing spontaneous hypothermia, with hypothermia per se, and with hypoxia while maintaining isothermia with external heat. The major findings were that (a) prior maternal-neonatal separation during the first week of postnatal life attenuated the plasma ACTH and corticosterone response to restraint stress in adult male but not female rats, (b) prior neonatal hypothermia augmented the plasma ACTH and corticosterone response to restraint stress in adult male rats, but not female rats, and (c) changes in hypothalamic, pituitary, and adrenal mRNA expression did not account for most of these HPA axis effects. Most of the programming effects on adult HPA axis was attributed to prior maternal-neonatal separation alone (with normoxia) because the addition of hypoxia with spontaneous hypothermia, hypothermia per se, and hypoxia while preventing hypothermia during maternal-neonatal separation had minimal effects on the HPA axis. These results may inform strategies to prevent sexually dimorphic sequelae of neonatal stress including those due to medical interventions.

Non-invasive biomarkers of fetal brain development reflecting prenatal stress: An integrative multi-scale multi-species perspective on data collection and analysis

Prenatal stress (PS) impacts early postnatal behavioural and cognitive development. This process of 'fetal programming' is mediated by the effects of the prenatal experience on the developing hypothalamic-pituitary-adrenal (HPA) axis and autonomic nervous system (ANS). We derive a multi-scale multi-species approach to devising preclinical and clinical studies to identify early non-invasively available pre- and postnatal biomarkers of PS. The multiple scales include brain epigenome, metabolome, microbiome and the ANS activity gauged via an array of advanced non-invasively obtainable properties of fetal heart rate fluctuations. The proposed framework has the potential to reveal mechanistic links between maternal stress during pregnancy and changes across these physiological scales. Such biomarkers may hence be useful as early and non-invasive predictors of neurodevelopmental trajectories influenced by the PS as well as follow-up indicators of success of therapeutic interventions to correct such altered neurodevelopmental trajectories. PS studies must be conducted on multiple scales derived from concerted observations in multiple animal models and human cohorts performed in an interactive and iterative manner and deploying machine learning for data synthesis, identification and validation of the best non-invasive detection and follow-up biomarkers, a prerequisite for designing effective therapeutic interventions.

Origin and dynamics of oligodendrocytes in the developing brain: Implications for perinatal white matter injury

Infants born prematurely are at high risk to develop white matter injury (WMI), due to exposure to hypoxic and/or inflammatory insults. Such perinatal insults negatively impact the maturation of oligodendrocytes (OLs), thereby causing deficits in myelination. To elucidate the precise pathophysiology underlying perinatal WMI, it is essential to fully understand the cellular mechanisms contributing to healthy/normal white matter development. OLs are responsible for myelination of axons. During brain development, OLs are generally derived from neuroepithelial zones, where neural stem cells committed to the OL lineage differentiate into OL precursor cells (OPCs). OPCs, in turn, develop into premyelinating OLs and finally mature into myelinating OLs. Recent studies revealed that OPCs develop in multiple waves and form potentially heterogeneous populations. Furthermore, it has been shown that myelination is a dynamic and plastic process with an excess of OPCs being generated and then abolished if not integrated into neural circuits. Myelination patterns between rodents and humans show high spatial and temporal similarity. Therefore, experimental studies on OL biology may provide novel insights into the pathophysiology of WMI in the preterm infant and offers new perspectives on potential treatments for these patients.

Insulin sensitivity, leptin, adiponectin, resistin, and testosterone in adult male and female rats after maternal-neonatal separation and environmental stress

Care of premature infants often requires parental and caregiver separation, particularly during hypoxic and hypothermic episodes. We have established a neonatal rat model of human prematurity involving maternal-neonatal separation and hypoxia with spontaneous hypothermia prevented by external heat. Adults previously exposed to these neonatal stressors show a sex difference in the insulin and glucose response to arginine stimulation suggesting a state of insulin resistance. The current study used this cohort of adult rats to evaluate insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR)], plasma adipokines (reflecting insulin resistance states), and testosterone. The major findings were that daily maternal-neonatal separation led to an increase in body weight and HOMA-IR in adult male and female rats and increased plasma leptin in adult male rats only; neither prior neonatal hypoxia (without or with body temperature control) nor neonatal hypothermia altered subsequent adult HOMA-IR or plasma adiponectin. Adult male-female differences in plasma leptin were lost with prior exposure to neonatal hypoxia or hypothermia; male-female differences in resistin were lost in the adults that were exposed to hypoxia and spontaneous hypothermia as neonates. Exposure of neonates to daily hypoxia without spontaneous hypothermia led to a decrease in plasma testosterone in adult male rats. We conclude that neonatal stressors result in subsequent adult sex-dependent increases in insulin resistance and adipokines and that our rat model of prematurity with hypoxia without hypothermia alters adult testosterone dynamics.

The impact of the Neonatal Intensive Care Unit on sensory and developmental outcomes in infants born preterm: A scoping review

Introduction

Preterm infants admitted to the Neonatal Intensive Care Unit are at higher risk of poor neurodevelopmental and sensory outcomes. There is interest in establishing whether elements of the Neonatal Intensive Care Unit sensory environment may influence the sensory and overall development of these infants.

Method

The purpose of this scoping review was to provide a comprehensive overview of relevant research regarding the sensory elements of the Neonatal Intensive Care Unit, and their short- and long-term influence on preterm infants. This scoping review is underpinned by the six-stage framework by Arksey and O’Malley.

Results

There are few studies that have directly examined the influence of the Neonatal Intensive Care Unit environment upon the sensory and developmental outcomes of infants born preterm, in infancy. The findings of the studies included in this review suggest that the Neonatal Intensive Care Unit sensory environment may alter developmental trajectories of preterm infants. However, low-quality evidence exists in this field, with much of the literature being preliminary.

Conclusion

Further experimental studies are required that combine multiple methods of assessment to more rigorously understand the sensory characteristics of the Neonatal Intensive Care Unit, and their relationship with developmental outcomes across early childhood.