Fathers’ and Mothers’ Infant Directed Speech Influences Preterm Infant Behavioral State in the NICU

Effects of parents' voice on reducing heel puncture pain in high-risk newborns: A randomized controlled trial

BACKGROUND

High-risk newborns, such as premature or severely ill infants, often experience painful treatments and separation from their parents. While previous studies have focused on the positive impacts of a mother's voice on newborns' physiology and pain response, research on the father's voice and vocal acoustics in high-risk newborns is limited.

AIM

To examine whether parents' voices reduce heel puncture pain in high-risk newborns and the relationship between parents' vocal acoustics, physiological parameters and pain response.

STUDY DESIGN

A randomized controlled clinical trial was conducted with 105 high-risk newborn-parent dyads. Participants were randomly assigned to three groups: recorded mother's voice, recorded father's voice or control group without any recorded voice. Outcome measures included heart rate, respiratory rate, oxygen saturation and pain response assessed using the Neonatal Infant Pain Scale. Data analysis utilized generalized estimation equations, and parents' vocal acoustics were analysed using Praat voice credit software.

RESULTS

The mother's voice group exhibited significantly lower heart rates at 1, 5 and 10 min after the procedure, along with lower respiratory rates and pain levels at 5 and 10 min after the procedure compared with the control group. Similarly, the father's voice group demonstrated significantly lower heart rates at 1 and 5 min after the procedure, decreased respiratory rates at 5 and 10 min after the procedure and reduced pain levels at 1 and 5 to 10 min after the procedure compared with the control group. Higher minimum and mean pitches in parents' voices correlated with slower heart rates, while slower parental speech was associated with reduced newborn pain.

CONCLUSION

Both maternal and paternal vocal interventions alleviated pain during heel puncture procedures among high-risk newborns.

RELEVANCE TO CLINICAL PRACTICE

The noninvasive intervention serves as a reference for parental participation in care. Nurses can help parents to intervene with the acoustic characteristics that alleviate pain among high-risk newborns.

Music Therapy in Infancy and Neurodevelopmental Outcomes in Preterm Children: A Secondary Analysis of the LongSTEP Randomized Clinical Trial

Importance

Preterm children are at risk for neurodevelopment impairments.

Objective

To evaluate the effect of a music therapy (MT) intervention (parent-led, infant-directed singing) for premature children during the neonatal intensive care unit (NICU) stay and/or after hospital discharge on language development at 24 months' corrected age (CA).

Design, Setting, and Participants

This predefined secondary analysis followed participants in the LongSTEP (Longitudinal Study of Music Therapy's Effectiveness for Premature Infants and Their Caregivers) randomized clinical trial, which was conducted from August 2018 to April 2022 in 8 NICUs across 5 countries (Argentina, Colombia, Israel, Norway, and Poland) and included clinic follow-up visits and extended interventions after hospital discharge.

Intervention

Participants were children born preterm (<35 weeks' gestation) and their parents. Participants were randomized at enrollment to MT with standard care (SC) or SC alone; they were randomized to MT or SC again at discharge. The MT was parent-led, infant-directed singing tailored to infant responses and supported by a music therapist and was provided 3 times weekly in the NICU and/or in 7 sessions across 6 months after discharge. The SC consisted of early intervention methods of medical, nursing, and social services, without MT.

Main Outcome and Measures

Primary outcome was language development, as measured by the Bayley Scales of Infant and Toddler Development, Third Edition (BSID-III) language composite score, with the remaining BSID-III composite and subscale scores as the secondary outcomes. Group differences in treatment effects were assessed using linear mixed-effects models using all available data.

Results

Of 206 participants (103 female infants [50%]; mean [SD] GA, 30.5 [2.7] weeks), 51 were randomized to MT and 53 to SC at enrollment; at discharge, 52 were randomized to MT and 50 to SC. A total of 112 (54%) were retained at the 24 months' CA follow-up. Most participants (79 [70%] to 93 [83%]) had BSID-III scores in the normal range (≥85). Mean differences for the language composite score were -2.36 (95% CI, -12.60 to 7.88; P = .65) for the MT at NICU with postdischarge SC group, 2.65 (95% CI, -7.94 to 13.23; P = .62) for the SC at NICU and postdischarge MT group, and -3.77 (95% CI, -13.97 to 6.43; P = .47) for the MT group at both NICU and postdischarge. There were no significant effects for cognitive or motor development.

Conclusions and Relevance

This secondary analysis did not confirm an effect of parent-led, infant-directed singing on neurodevelopment in preterm children at 24 months' CA; wide CIs suggest, however, that potential effects cannot be excluded. Future research should determine the MT approaches, implementation time, and duration that are effective in targeting children at risk for neurodevelopmental impairments and introducing broader measurements for changes in brain development.

Trial Registration

ClinicalTrials.gov Identifier: NCT03564184.

The Response of the Infant to the Father's Voice: An Evidence-Based Review

BACKGROUND

Premature infants are at increased risk for language delays. The auditory system hears sounds at 25 weeks' gestation; therefore, infants in the neonatal intensive care unit (NICU) may miss crucial language exposure during the period when neural pathways for language processing are developing. Supporting the synergistic relationship between fathers and newborns promotes connections through early language to strengthen engagement and promote infant neurodevelopment.

PURPOSE

To determine what is known about preterm infants' response to the male voice.

DATA SOURCES

Three databases and forward searching of reference lists were used to locate articles addressing the clinical question: "What strategies can be used in the NICU to support purposeful language development?"

STUDY SELECTION

Empiric, primary research studies were included if they were published in English without date restriction.

DATA EXTRACTION

The authors evaluated each study's quality using a validated 16-item assessment tool (QATSDD) developed for studies with diverse designs; data were extracted and organized following Garrard's Matrix Method.

RESULTS

The aim of this evidence-based review is to report the way an infant responds to the paternal voice. Findings promote a better understanding of individual infant response to paternal voice, including conversational turns and engagement behaviors. Although informative, this review highlights a clear gap in the evidence, supporting standardized methodology.

IMPLICATIONS FOR PRACTICE AND RESEARCH

Fathers should be encouraged to communicate vocally early and often to facilitate bonding in the NICU. Encouraged future study of father-infant communication to support bonding, relationship building, and neurodevelopmental outcomes is paramount.

Language environment and parent-infant close contact in neonatal care and emerging lexical abilities of very preterm children-a longitudinal study

AIM

This longitudinal study investigated associations between language environment and parent-infant close contact in the neonatal intensive care unit (NICU) and preterm children's lexical abilities.

METHODS

NICU language environment of 43 very preterm infants (born<32 gestational weeks) was measured with the Language Environment Analysis System (LENA; variables: number of adult words, conversational turns, and child vocalisations). Parent-infant close contact (holding and skin-to-skin contact) in the NICU was reported using parental closeness diaries. At 15 and 18 months' corrected age, lexical development was measured with screening methods, and eye tracking-based lexical processing was assessed at 18 months. N varied between 29 and 38 in different outcome measures.

RESULTS

LENA measured conversational turns and child vocalisations, and parent-infant close contact associated positively with lexical development (r = 0.35-0.57). High numbers of NICU adult words associated negatively with lexical processing (r = -0.38- -0.40). In regression models, conversational turns and parent-infant close contact explained 34%-35% of receptive development.

CONCLUSION

Findings suggest that adult-infant turn taking and parent-infant close contact in the NICU are positively associated with lexical development. High numbers of overheard words in the NICU may not favour later lexical processing. Further research is warranted on the significance of NICU language environment on later lexical abilities.

Oxytocin Levels Increase and Anxiety Decreases in Mothers Who Sing and Talk to Their Premature Infants during a Painful Procedure

(1) Background: Preterm infants spend their first weeks of life in the hospital partially separated from their parents and subjected to frequent potentially painful clinical procedures. Previous research has found that early vocal contact reduces infant pain perception while simultaneously increasing oxytocin (OXT) levels. The current study aims to assess the effect of maternal singing and speaking on mothers. (2) Methods: During a painful procedure over two days, twenty preterm infants were randomly exposed to their mother's live voice (speaking or singing). Maternal OXT levels were measured twice: before and after singing, as well as before and after speaking. The anxiety and resilience responses of mothers were studied before and after the two-day interventions, regardless of the speaking/singing condition. OXT levels in mothers increased in response to both singing and speech. Concurrently, anxiety levels decreased, but no significant effects on maternal resilience were found. (3) Conclusions: OXT could be identified as a key mechanism for anxiety regulation in parents, even in sensitive care situations, such as when their infant is in pain. Active involvement of parents in the care of their preterm infants can have a positive effect on their anxiety as well as potential benefits to their sensitivity and care abilities through OXT.

Maternal Voice Exposure and Its Effect on Premature Infants' Feeding Milestones: A Systematic Review

BACKGROUND

Premature infants experience alterations in maternal stimulation (including auditory sensory alteration such as talking or singing to the infant in the neonatal intensive care unit) due to admission to the neonatal intensive care unit. Because of their physiological and neurobehavioral immaturity, infants are at an increased risk of delays in reaching feeding milestones (a key developmental milestone), which often need to be achieved before discharge.

PURPOSE

This systematic review evaluated the literature regarding the effect of maternal speech on achievement of feeding milestones in premature infants.

DATA SOURCES

A systematic search of CINAHL, PubMed, Web of Science, and Google Scholar from 2010 to 2021.

STUDY SELECTION

Studies were selected if they examined the effect of maternal voice interventions on premature infants' feeding milestones.

DATA EXTRACTION

Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were used.

RESULTS

Six studies were identified. This systematic review of the literature on the effects of maternal voice on feeding milestones in premature infants found equivocal results.

IMPLICATIONS FOR PRACTICE

Given the inconsistent results, this systematic review does not support a change in clinical practice. However, encouragement of maternal visits is highly recommended as the additional benefits of the mother's presence may extend beyond exposure to maternal voice.

IMPLICATIONS FOR RESEARCH

More research is needed including use of more homogenous samples, application of recommended decibel levels, and utilization of an adequately powered randomized controlled trial to further examine the effects of maternal voice on feeding milestones.

Comparison of Effects of Mothers' and Mozart's Lullabies on Physiological Responses, Feeding Volume, and Body Weight of Premature Infants in NICU

Objectives

The purpose of this study was to compare the effects of mothers' and Mozart's lullabies on physiological parameters, feeding volume, and body weight of premature infants in a neonatal intensive care unit (NICU).

Methods

This study used a non-equivalent control group, non-synchronized design as a quasi-experimental study. Two intervention groups (recorded mother's lullaby and Mozart's lullaby) and a control group were formed from a total of 65 premature infants: a mother's lullaby group of 22 infants, a Mozart's lullaby group of 22 infants, and a control group of 21 infants not provided with any lullabies. Their physiological parameters included heart rate, blood pressure, respiratory rate, and O2 saturation. The infants' feeding volume and body weight were measured as indicators related to the growth of premature infants. The mother's and Mozart's lullabies were played on a speaker in an incubator for 15 min for 7 consecutive days per group.

Results

There were significant differences in the mean difference before and after intervention in neonatal heart rate (χ2 = 45.03, P < 0.001), systolic pressure (F = 43.29, P < 0.001), diastolic pressure (χ2 = 33.01, P < 0.001), respiratory rate (F = 76.06, P < 0.001), and O2 saturation (χ2 = 40.82, P < 0.001) between the three groups. The mean differences of both mother's and Mozart's lullaby groups were significantly higher than those of the routine care group in all physiological parameters, and those of the mother's lullaby group was significantly higher when compared with the Mozart's lullaby group. In repeated-measures ANOVA, there was a significant interaction between time and group in feeding volume (F = 2.46, P = 0.041). However, body weight did not significantly differ in an interaction between time and group (F = 1.75, P = 0.151).

Conclusion

This study showed beneficial effects of mother's lullaby and Mozart's lullaby on physiological parameters. Especially, the mother's lullaby was found to significantly improve all physiological parameters and feeding volume of premature infants in the NICU compared to Mozart's lullaby group. Therefore, we recommend the regular integration of the mother's lullaby into supportive care of premature infants in the NICU, as this intervention highlights the need for mothers to participate in their care.

Trial Registration

ClinicalTrials.gov, identifier: KCT0004842 (https://cris.nih.go.kr).

The Implications of COVID-19 on Family-Centered Care in the NICU

During the recent COVID-19 pandemic, neonatal intensive care units (NICUs) issued strict visiting policies that limited parent visitation and impacted how family-centered care was practiced. This article describes how these visiting policies impacted parents and neonates. Implications for clinical practice and future research will also be discussed.

Systematic review shows the benefits of involving the fathers of preterm infants in early interventions in neonatal intensive care units

Aim

This review identifies interventions involving the fathers of preterm infants that have been tested in neonatal intensive care units (NICU). It examines their effects on the fathers and infants and highlights any differences between fathers and mothers who took part in the same interventions.

Methods

A systematic search was performed in English from 1995 to 1 September 2020, using the CINAHL, Cochrane Central Register of Controlled Trials, Embase, PubMed and PsycINFO databases. We examined 14 peer‐reviewed studies that investigated NICU interventions involving 478 fathers, whose 511 infants were born before 37 weeks of gestation. These included empirical studies with clinical outcomes.

Results

Studies on fathers' interventions in NICUs were limited and mainly restricted to basic skin‐to‐skin contact or tactile interventions. The interventions had similar general positive effects on mothers and fathers when it came to infant physiological and behavioural reactions. There was also evidence of a positive effect on the fathers, including their mental health.

Conclusion

Including fathers as active partners in the care of their preterm newborn infants produced good outcomes for both of them. Further research is needed to develop new, multimodal and interactive interventions that provide fathers with positive contact with their preterm infants.

Maternal speech decreases pain scores and increases oxytocin levels in preterm infants during painful procedures

Preterm infants undergo early separation from parents and are exposed to frequent painful clinical procedures, with resultant short- and long-term effects on their neurodevelopment. We aimed to establish whether the mother's voice could provide an effective and safe analgesia for preterm infants and whether endogenous oxytocin (OXT) could be linked to pain modulation. Twenty preterm infants were exposed to three conditions-mother's live voice (speaking or singing) and standard care-in random order during a painful procedure. OXT levels (pg/mL) in saliva and plasma cortisol levels were quantified, and the Premature Infant Pain Profile (PIPP) was blindly coded by trained psychologists. During the mother's live voice, PIPP scores significantly decreased, with a concomitant increase in OXT levels over baseline. The effect on pain perception was marginally significant for singing. No effects on cortisol levels were found. The mother's live voice modulated preterm infants' pain indicators. Endogenous OXT released during vocal contact is a promising protective mechanism during early painful interventions in at-risk populations.

Parental Perception of Vocal Contact with Preterm Infants: Communicative Musicality in the Neonatal Intensive Care Unit

In this study, we evaluate mothers’ subjective experience of speaking and singing to their infants while they are in their incubators. We also discuss the relevance of the theoretical framework of Communicative Musicality for identifying the underlying mechanisms that may help explain its beneficial effects, both for parents and infants. Nineteen mothers talked and sung to their stable preterm infants in the incubators, for 5 min each, in three sessions over a period of 6 days. After each session, mothers were asked to assess in a self-report questionnaire the ease and the effectiveness of addressing their infants by speaking and singing and their prior musical experience. Perceived ease and effectiveness in communication were found to increase progressively from one session to the next. Mothers rated the speech to be increasingly more effective. This intuitive mean of interaction between parents and infants could be encouraged and supported by the nurses and the medical staff. Furthermore, individual musical experience affects perceived ease of communicating vocally with infants after a premature birth and should thus be encouraged during pregnancy.

Effects of Early Vocal Contact in the Neonatal Intensive Care Unit: Study Protocol for a Multi-Centre, Randomised Clinical Trial

Preterm infants are at risk for developing altered trajectories of cognitive, social, and linguistic competences compared to a term population. This is mainly due to medical and environmental factors, as they are exposed to an atypical auditory environment and simultaneously, long periods of early separation from their parents. The short-term effects of early vocal contact (EVC) on an infant’s early stability have been investigated. However, there is limited evidence of its impact on the infant’s autonomic nervous system maturation, as indexed by heart rate variability, and its long-term impact on infant neurodevelopment. Our multi-centric study aims to investigate the effects of EVC on a preterm infant’s physiology, neurobehaviour, and development. Eighty stable preterm infants, born at 25–32 weeks and 6 days gestational age, without specific abnormalities, will be enrolled and randomised to either an intervention or control group. The intervention group will receive EVC, where mothers will talk and sing to their infants for 10 min three times per week for 2 weeks. Mothers in the control group will be encouraged to spend the same amount of time next to the incubator and observe the infant’s behaviour through a standard cluster of indicators. Infants will be assessed at baseline; the end of the intervention; term equivalent age; and 3, 6, 12, and 24 months corrected age, with a battery of physiological, neurobehavioral, and developmental measures. Early interventions in the neonatal intensive care unit have demonstrated effects on the neurodevelopment of preterm infants, thereby lowering the negative long-term effects of an atypical auditory and interactional environment. Our proposed study will provide new insight into mother–infant early contact as a protective intervention against the sequelae of prematurity during this sensitive period of development. Early intervention, such as EVC, is intuitive and easy to implement in the daily care of preterm infants. However, its long-term effects on infant neurodevelopment and maternal sensitivity and stress are still unclear. Trial Registration: NCT04759573, retrospectively registered, 17 February 2021.

Introduction to the Special Issue on Nonverbal Vocal Communication in Development

Nonverbal vocal aspects of communication, often related to affective states, are crucial to social interactions not only for animals but also for humans during early infancy, as well as being one of the pillars of human language development and acquisition. The thread that binds together the contributions to this Special Issue is the analysis of nonverbal vocal communication during development, both from ontogenetic and phylogenetic perspectives. This introduction presents the multiple viewpoints emerging from this Special Issue and delineates future research directions for investigating the nonverbal aspects of vocal communication in early development.