A risk of sensory deprivation in the neonatal intensive care unit

Multisensory stimulation for promoting development and preventing morbidity in preterm infants

OBJECTIVES

This is a protocol for a Cochrane Review (intervention). The objectives are as follows: To assess the benefits and harms of multisensory stimulation compared to any single sensory intervention or standard care for physical and neurological development in preterm infants.

Supporters' experiences of sensory characteristics of children with profound intellectual and multiple disabilities in after-school daycare centres: A qualitative study

AIM

To examine how supporters working at after-school daycare centres, who are involved in the lives of children with profound intellectual and multiple disabilities in the community, pay attention to the sensory characteristics of these children and provide support.

DESIGN

A qualitative descriptive design.

METHODS

Data were collected through semi-structured interviews with 20 supporters in after-school daycare centres. Interview transcripts were analysed via qualitative content analysis.

RESULTS

The participants' years of involvement in supporting children with profound intellectual and multiple disabilities ranged from 0.5 to 40 years, with an average of 9.8 years. Data were classified into 68 subcategories, 11 categories and three themes: understanding sensory characteristics and devising support, systematic support and challenges supporting the children. Supporters dealt with physical complications and cooperated with other caregivers to understand and respond to children's sensory characteristics. Difficulties dealing with sensory characteristics, challenges due to the supporters' own characteristics and challenges with the facility's infrastructure were identified. The findings could guide sensory characteristics considerations and support systems in after-school daycare facilities for children with profound intellectual and multiple disabilities. Both support content and challenges in supporting these children were identified.

Language Exposure for Preterm Infants is Reduced Relative to Fetuses

OBJECTIVE

To assess changes and deficits in language and auditory exposures consequent to preterm birth and neonatal intensive care unit stay compared with exposures in utero among typically developing fetuses.

STUDY DESIGN

We analyzed over 23 000 hours of auditory exposure data in a cohort study of 27 typically-developing fetuses and 24 preterm infants. Extrauterine exposures for fetuses were captured by having pregnant women wear 24-hour audio recording devices. For preterm infants, recording devices were placed in the infant's crib. Multilevel linear regressions were conducted to test for group differences and effects of infant sex, maternal education, and mother' occupation. A linear mixed-effects model was used to test for an effect of speaker gender.

RESULTS

Fetuses were exposed to an estimated 2.6 ± 1.8 hours/day of nearby, predominantly female language, nearly 5 times greater than 32 ± 12 minutes/day estimated for preterm infants (P < .001). Preterm infants had greater daily exposure to electronic sounds (5.1 ± 2.5 vs 1.3 ± 0.6 hours; P < .001) and noise (4.4 ± 2.1 vs 2.9 ± 2.8 hours; P < .05), with 4.7 ± 3.9 hours/day of silence. Language and extrauterine sound exposure for fetuses showed a marked day/night cyclical pattern, with low exposure during nighttime hours, but preterm infants' exposures showed significantly less change across the 24-hour cycle (P < .001). Maternal occupation requiring frequent communication predicted greater language exposure (P < .05).

CONCLUSIONS

Our findings provide the first comparison of preterm infant auditory exposures to typically-developing fetuses. Some preterm infants may incur deficits of over 150 hours of language exposure over the preterm period. Given known effects of prenatal/preterm language exposure on neurobehavioral outcomes, this magnitude of deficit is alarming.

Multisensory stimulation to promote feeding and psychomotor development in preterm infants: A systematic review

BACKGROUND

Sensory stimulation is an intervention that, through peripheral stimuli, can facilitate brain organization, due to neuronal plasticity and cortical reorganization. The objective of this study was to evaluate the evidence about the effects of a multisensory stimulation program, applied on preterm infants, compared to any intervention or standard care, to improve feeding behaviour, and psychomotor development.

METHODS

The data sources included Medline (pubmed, EBSCO), Scopus and Web Of Science. The studies were randomized clinical trials published between 2015 and 2021 that analyzed multisensory stimulation interventions in preterm infants born less than 37 weeks of pregnancy.

RESULTS

Nine articles were identified, involving 545 preterm infants between 25 and 37 weeks of pregnancy. The studies applied different combinations of sensory stimulation. These interventions were related to a better time to achieve full oral feeding and higher consumption of human milk at discharge, better psychomotor development and visual function. All studies scored 6 or higher on the PEDro scale meaning good quality.

CONCLUSION

Multisensory stimulation in preterm infants may improve feeding, psychomotor development, and visual function.

A Survey of Neonatal Nurses Perspectives on Voice Use and Auditory Needs with Premature Infants in the NICU

BACKGROUND

Exposure to the voice and language during the critical period of auditory development associated with the third trimester is thought to be an essential building block for language. Differences in the auditory experience associated with early life in the NICU may increase the risk of language delays for premature infants. NICU nurses are fundamental in the care of premature infants; how they use their voices may be important in understanding auditory experiences in the NICU. This study examined voice use behaviors of NICU nurses in the United States and their current knowledge of early auditory development.

METHOD

An opt-in, online questionnaire.

RESULTS

Nurses reported using their voice more as the age of infants approached term gestation and speaking to infants was the most common type of voice use. Both infant and nurse factors influenced reported voice use decisions in the NICU. Nurses did not believe the NICU auditory environment to be sufficient to meet early auditory needs of premature infants but did believe that premature infants are exposed to adequate voice sounds.

CONCLUSIONS

A gap in knowledge regarding the importance of early exposure to voice sounds may be a barrier to nurses using their voices to support early auditory development.

Premature Birth and Developmental Programming: Mechanisms of Resilience and Vulnerability

The third trimester of pregnancy represents a sensitive phase for infant brain plasticity when a series of fast-developing cellular events (synaptogenesis, neuronal migration, and myelination) regulates the development of neural circuits. Throughout this dynamic period of growth and development, the human brain is susceptible to stress. Preterm infants are born with an immature brain and are, while admitted to the neonatal intensive care unit, precociously exposed to stressful procedures. Postnatal stress may contribute to altered programming of the brain, including key systems such as the hypothalamic-pituitary-adrenal axis and the autonomic nervous system. These neurobiological systems are promising markers for the etiology of several affective and social psychopathologies. As preterm birth interferes with early development of stress-regulatory systems, early interventions might strengthen resilience factors and might help reduce the detrimental effects of chronic stress exposure. Here we will review the impact of stress following premature birth on the programming of neurobiological systems and discuss possible stress-related neural circuits and pathways involved in resilience and vulnerability. Finally, we discuss opportunities for early intervention and future studies.

Variations in patterns of care across neonatal units and their associations with outcomes in very preterm infants: the French EPIPAGE-2 cohort study

OBJECTIVES

To describe patterns of care for very preterm (VP) babies across neonatal intensive care units (NICUs) and associations with outcomes.

DESIGN

Prospective cohort study, EPIPAGE-2.

SETTING

France, 2011.

PARTICIPANTS

53 (NICUs); 2135 VP neonates born at 27 to 31 weeks.

OUTCOME MEASURES

Clusters of units, defined by the association of practices in five neonatal care domains - respiratory, cardiovascular, nutrition, pain management and neurodevelopmental care. Mortality at 2 years corrected age (CA) or severe/moderate neuro-motor or sensory disabilities and proportion of children with scores below threshold on the neurodevelopmental Ages and Stages Questionnaire (ASQ).

METHODS

Hierarchical cluster analysis to identify clusters of units. Comparison of outcomes between clusters, after adjustment for potential cofounders.

RESULTS

Three clusters were identified: Cluster 1 with higher proportions of neonates free of mechanical ventilation at 24 hours of life, receiving early enteral feeding, and neurodevelopmental care practices (26 units; n=1118 babies); Cluster 2 with higher levels of patent ductus arteriosus and pain screening (11 units; n=398 babies); Cluster 3 with higher use of respiratory, cardiovascular and pain treatments (16 units; n=619 babies). No difference was observed between clusters for the baseline maternal and babies' characteristics. No differences in outcomes were observed between Clusters 1 and 3. Compared with Cluster 1, mortality at 2 years CA or severe/moderate neuro-motor or sensory disabilities was lower in Cluster 2 (adjusted OR 0.46, 95% CI 0.25 to 0.84) but with higher proportion of children with an ASQ below threshold (adjusted OR 1.49, 95% CI 1.07 to 2.08).

CONCLUSION

In French NICUs, care practices for VP babies were non-randomly associated. Differences between clusters were poorly explained by unit or population differences, but were associated with mortality and development at 2 years. Better understanding these variations may help to improve outcomes for VPT babies, as it is likely that some of these discrepancies are unwarranted.

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.

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.

Neonatal stress and resilience - lasting effects of antenatal corticosteroids 1

Antenatal corticosteroids (ACS) are standard of care for women at risk of preterm delivery between 24 and 34 weeks gestation. Their use decreases preterm morbidities and mortality. However, ACS treatments mimic a stress response by increasing fetal steroid levels at early gestational ages when the fetus is normally protected from high glucocorticoid levels. Within the context of concept of the developmental origins of adult health and disease, ACS are effective stressors in fetal animal models that alter developmental programs and outcome in adult animals. Although few short-term adverse effects of ACS in infants and children are apparent, there are cohort studies demonstrating cognitive, metabolic, and cardiovascular effects in humans beyond 30 years of age. ACS likely interact with other stresses - maternal diseases complicating prematurity, premature delivery, and nutritional deficiencies - to program outcomes that may not be known for many years. The risks of ACS will increase as indications for ACS increase to late gestation preterm infants and possibly Cesarean-section deliveries.

Noise in the neonatal intensive care unit: a new approach to examining acoustic events

INTRODUCTION

Environmental noise is associated with negative developmental outcomes for infants treated in the neonatal intensive care unit (NICU). The existing noise level recommendations are outdated, with current studies showing that these standards are universally unattainable in the modern NICU environment.

STUDY AIM

This study sought to identify the types, rate, and levels of acoustic events that occur in the NICU and their potential effects on infant physiologic state.

MATERIALS AND METHODS

Dosimeters were used to record the acoustic environment in open and private room settings of a large hospital NICU. Heart and respiratory rate data of three infants located near the dosimeters were obtained. Infant physiologic data measured at time points when there was a marked increase in sound levels were compared to data measured at time points when the acoustic levels were steady.

RESULTS

All recorded sound levels exceeded the recommended noise level of 45 decibels, A-weighted (dBA). The 4-h Leq of the open-pod environment was 58.1 dBA, while the private room was 54.7 dBA. The average level of acoustic events was 11-14 dB higher than the background noise. The occurrence of transient events was 600% greater in the open room when compared to the private room. While correlations between acoustic events and infant physiologic state could not be established due to the extreme variability of infant state, a few trends were visible. Increasing the number of data points to overcome the extreme physiologic variability of medically fragile neonates would not be feasible or cost-effective in this environment.

CONCLUSION

NICU noise level recommendations need to be modified with an emphasis placed on reducing acoustic events that disrupt infant state. The goal of all future standards should be to optimize infant neurodevelopmental outcomes.

Differential Rates of Perinatal Maturation of Human Primary and Nonprimary Auditory Cortex

Primary and nonprimary cerebral cortex mature along different timescales; however, the differences between the rates of maturation of primary and nonprimary cortex are unclear. Cortical maturation can be measured through changes in tissue microstructure detectable by diffusion magnetic resonance imaging (MRI). In this study, diffusion tensor imaging (DTI) was used to characterize the maturation of Heschl's gyrus (HG), which contains both primary auditory cortex (pAC) and nonprimary auditory cortex (nAC), in 90 preterm infants between 26 and 42 weeks postmenstrual age (PMA). The preterm infants were in different acoustical environments during their hospitalization: 46 in open ward beds and 44 in single rooms. A control group consisted of 15 term-born infants. Diffusion parameters revealed that (1) changes in cortical microstructure that accompany cortical maturation had largely already occurred in pAC by 28 weeks PMA, and (2) rapid changes were taking place in nAC between 26 and 42 weeks PMA. At term equivalent PMA, diffusion parameters for auditory cortex were different between preterm infants and term control infants, reflecting either delayed maturation or injury. No effect of room type was observed. For the preterm group, disturbed maturation of nonprimary (but not primary) auditory cortex was associated with poorer language performance at age two years.

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

OBJECTIVE

Very preterm infants hospitalized in the neonatal intensive care unit (NICU) experience alterations in sensory experiences. Defining types, timing and frequency of sensory-based interventions that optimize outcomes can inform environmental modifications. The objective of this study was to conduct an integrative review on sensory-based interventions used with very preterm infants in the NICU to improve infant and parent outcomes.

STUDY DESIGN

The data sources include MEDLINE, CINAHL, Cochrane Library and Google Scholar. Studies were identified that used sensory-based interventions in the NICU with preterm infants born ⩽32 weeks gestation, were published in a peer-reviewed journal between 1995 and 2015, and measured outcomes related to infant and parent outcomes. Studies were extracted from electronic databases and hand-searched from identified reference lists.

RESULTS

Eighty-eight articles were identified (31 tactile, 12 auditory, 3 visual, 2 kinesthetic, 2 gustatory/olfactory and 37 multimodal). There was evidence to support the use of kangaroo care, music and language exposure, and multimodal interventions starting at 25 to 28 weeks postmenstrual age. These interventions were related to better infant development and lower maternal stress, but not all findings were consistent. Limitations included lack of consistent outcome measures, study quality and gaps in the literature.

CONCLUSIONS

Most research identified interventions that were done for short periods of time. It is unclear what the potential is for improving outcomes if positive sensory exposures occur consistently throughout NICU hospitalization. Until more research defines appropriate sensory-based interventions to use with infants born very preterm in the NICU, information from this review can be combined with expert opinion and parent/family values to determine best practice.

Translating Neurodevelopmental Care Policies Into Practice: The Experience of Neonatal ICUs in France-The EPIPAGE-2 Cohort Study

OBJECTIVES

To describe the implementation of neurodevelopmental care for newborn preterm infants in neonatal ICUs in France in 2011, analyze changes since 2004, and investigate factors associated with practice.

DESIGN

Prospective national cohort study of all births before 32 weeks of gestation.

SETTING

Twenty-five French regions.

PARTICIPANTS

All neonatal ICUs (n = 66); neonates surviving at discharge (n = 3,005).

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Neurodevelopmental care policies and practices were assessed by structured questionnaires. Proportions of neonates initiating kangaroo care during the first week of life and those whose mothers expressed breast milk were measured as neurodevelopmental care practices. Multilevel logistic regression analyses were used to investigate relationships between kangaroo care or breast-feeding practices and unit policies, taking into account potential confounders. Free visiting policies, bed availability for parents, and kangaroo care encouragement significantly improved between 2004 and 2011 but with large variabilities between units. Kangaroo care initiation varied from 39% for neonates in the most restrictive units to 68% in less restrictive ones (p < 0.001). Individual factors associated with kangaroo care initiation were gestational age (odds ratio, 5.79; 95% CI, 4.49-7.48 for babies born at 27-31 wk compared with babies born at 23-26 wk) and, to a lesser extent, single pregnancy, birthweight above the 10th centile, and mother's employment before pregnancy. At unit level, policies and training in neurodevelopmental care significantly influenced kangaroo care initiation (odds ratio, 3.5; 95% CI, 1.8-7.0 for Newborn Individualized Developmental Care and Assessment Program implementation compared with no training). Breast milk expression by mothers was greater in units with full-time availability professionals trained for breast-feeding support (60% vs 73%; p < 0.0001).

CONCLUSIONS

Dissemination of neurodevelopmental practices occurred between 2004 and 2011, but large variabilities between units persist. Practices increased in units with supportive policies. Specific neurodevelopmental care training with multifaceted interventions strengthened the implementation of policies.

Effects of standardized acoustic stimulation in premature infants: a randomized controlled trial

OBJECTIVE

The objective of this study was to investigate the effects of recorded lullabies and taped maternal voice in premature infants.

STUDY DESIGN

Sixty-two preterm infants in a stable condition with 30<37 weeks of gestation and <10 days of postnatal age were randomly assigned to hear (A) recorded lullabies or (B) taped maternal voice for 30 min each evening during 14 consecutive days or (C) receive no standardized acoustic stimulation (control group). Heart rate and respiratory rate were recorded daily before, during and after the intervention (A and B) or a comparable period with no intervention (C), whereas activity was measured on days 1, 7 and 14 of the intervention using accelerometers.

RESULTS

Both interventions led to a significant decrease in heart rate and respiratory rate during and after the stimulation when compared with the control group. The changes were more pronounced in infants with higher gestational ages (P=0.001). Lower activity was measured during the intervention when compared with the control group (P<0.01).

CONCLUSIONS

Standardized acoustic stimulation with recorded lullabies and taped maternal voice led to a decrease in heart rate and respiratory rate, and was associated with lower activity. Whether this indicates a reduced stress reaction needs to be investigated in further studies.

Characterising the ambient sound environment for infants in intensive care wards

AIM

The purpose of this study is to characterise ambient sound levels of paediatric and neonatal intensive care units in an old and new hospital according to current standards.

METHODS

The sound environment was surveyed for 24-h data collection periods (n = 80) in the Neonatal and Paediatric Intensive Care Units (NICUs and PICUs) and Special Care Nursery of the old and new Royal Children's Hospital Melbourne. The ambient sound environment was characterised as the proportion of time the ongoing ambient sound met standard benchmarks, the mean 5-s sound levels and the number and duration of noise events.

RESULTS

In the old hospital, none of the data collection periods in the NICU and PICU met the standard benchmark for ongoing ambient sound, while only 5 of the 22 data collection periods in the new hospital met the recommended level. There was no change in proportion of time at recommended Leq between the old and the new Special Care Nursery. There was strong evidence for a difference in the mean number of events >65 dBA (Lmax ) in the old and new hospital (rate ratio = 0.82, 95% confidence interval: 0.73 to 0.92, P = 0.001). The NICU and PICU were above 50 dBA in 75% of all data collection periods, with ventilatory equipment associated with higher ongoing ambient sound levels.

CONCLUSIONS

The ongoing ambient sound suggests that the background sound environment of the new hospital is not different to the old hospital. However, there may be a reduction in the number of noise events.

Constructing optimal experience for the hospitalized newborn through neuro-based music therapy

Music-based intervention for hospitalized newborn infants has traditionally been based in a biomedical model, with physiological stability as the prime objective. More recent applications are grounded in other theories, including attachment, trauma and neurological models in which infant, parent and the dyadic interaction may be viewed as a dynamic system bound by the common context of the neonatal intensive care unit (NICU). The immature state of the preterm infant’s auditory processing system requires a careful and individualized approach for the introduction of purposeful auditory experience intended to support development. The infant’s experience of an unpredictable auditory environment is further compromised by a potential lack of meaningful auditory stimulation. Parents often feel disconnected from their own capacities to nurture their infant with potentially life-long implications for the infant’s neurobehavioral and psychological well-being. This perspectives paper will outline some neurological considerations for auditory processing in the premature infant to frame a premise for music-based interventions. A hypothetical clinical case will illustrate the application of music by a music therapist with an infant and family in NICU.

Mother's voice and heartbeat sounds elicit auditory plasticity in the human brain before full gestation

Brain development is largely shaped by early sensory experience. However, it is currently unknown whether, how early, and to what extent the newborn's brain is shaped by exposure to maternal sounds when the brain is most sensitive to early life programming. The present study examined this question in 40 infants born extremely prematurely (between 25- and 32-wk gestation) in the first month of life. Newborns were randomized to receive auditory enrichment in the form of audio recordings of maternal sounds (including their mother's voice and heartbeat) or routine exposure to hospital environmental noise. The groups were otherwise medically and demographically comparable. Cranial ultrasonography measurements were obtained at 30 ± 3 d of life. Results show that newborns exposed to maternal sounds had a significantly larger auditory cortex (AC) bilaterally compared with control newborns receiving standard care. The magnitude of the right and left AC thickness was significantly correlated with gestational age but not with the duration of sound exposure. Measurements of head circumference and the widths of the frontal horn (FH) and the corpus callosum (CC) were not significantly different between the two groups. This study provides evidence for experience-dependent plasticity in the primary AC before the brain has reached full-term maturation. Our results demonstrate that despite the immaturity of the auditory pathways, the AC is more adaptive to maternal sounds than environmental noise. Further studies are needed to better understand the neural processes underlying this early brain plasticity and its functional implications for future hearing and language development.