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

Defining the Concept of Acoustic Neuroprotection in the Neonate: A Concept Analysis

BACKGROUND

It has long been understood and acknowledged that the Neonatal Intensive Care Unit (NICU) environment and the transport environments are extremely loud, with both long- and short-term sequelae to the neonate, being well over the recommended amount of noise by the American Academy of Pediatrics (AAP). This problem has yet to be properly addressed. The purpose of this manuscript is to define and explain the concept of acoustic neuroprotection. While we cannot change the internal structures of the neonates' auditory system, we could change the acoustics of the environment to be support neuroprotection of these sensitive patients.

EVIDENCE ACQUISITION

Walker and Avant's concept analysis steps were followed to create and define the idea of acoustic neuroprotection, as it has not had a definition before. A total of 45 articles from multiple search engines were chosen. A combination of 2 concepts were used: acoustic protection and neurodevelopmental protection/support. The search was expanded past 20 years for lack of research and importance of seminal works.

RESULTS

To achieve acoustic neuroprotection, a neonate should not be exposed to sound greater than 45 decibels (dBa) for longer than 10 s, and exposure to sound above 80 dBa should never occur. Appropriate interventions need to include supporting the neurodevelopment of the neonate through therapeutic sound, while decreasing the amount of toxic noise exposure to safe levels.

IMPLICATIONS FOR PRACTICE AND RESEARCH

By further understanding and having a quantifiable goal of acoustic neuroprotection for neonates, neonatal clinicians can work together to create new interventions for how to better protect and support the care of our tiniest patients.

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.

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.

An Animal Model of Neonatal Intensive Care Unit Exposure to Light and Sound in the Preterm Infant

According to the World Health Organization, ∼15 million children are born prematurely each year. Many of these infants end up spending days to weeks in a neonatal intensive care unit (NICU). Infants who are born prematurely are often exposed to noise and light levels that affect their auditory and visual development. Children often have long-term impairments in cognition, visuospatial processing, hearing, and language. We have developed a rodent model of NICU exposure to light and sound using the Mongolian gerbil (Meriones unguiculatus), which has a low-frequency human-like audiogram and is altricial. To simulate preterm infancy, the eyes and ears were opened prematurely, and animals were exposed to the NICU-like sensory environment throughout the gerbil's cortical critical period of auditory development. After the animals matured into adults, auditory perceptual testing was carried out followed by auditory brainstem response recordings and then histology to assess the white matter morphology of various brain regions. Compared to normal hearing control animals, NICU sensory-exposed animals had significant impairments in learning at later stages of training, increased auditory thresholds reflecting hearing loss, and smaller cerebellar white matter volumes. These have all been reported in longitudinal studies of preterm infants. These preliminary results suggest that this animal model could provide researchers with an ethical way to explore the effects of the sensory environment in the NICU on the preterm infant's brain development.

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.

Speech-in-noise testing: Innovative applications for pediatric patients, underrepresented populations, fitness for duty, clinical trials, and remote services

Speech perception testing, defined as providing standardized speech stimuli and requiring a listener to provide a behavioral and scored response, has been an integral part of the audiologic test battery since the beginning of the audiology profession. Over the past several decades, limitations in the diagnostic and prognostic validity of standard speech perception testing as routinely administered in the clinic have been noted, and the promotion of speech-in-noise testing has been highlighted. This review will summarize emerging and innovative approaches to speech-in-noise testing with a focus on five applications: (1) pediatric considerations promoting the measurement of sensory and cognitive components separately; (2) appropriately serving underrepresented populations with special attention to racial, ethnic, and linguistic minorities, as well as considering biological sex and/or gender differences as variables of interest; (3) binaural fitness for duty assessments of functional hearing for occupational settings that demand the ability to detect, recognize, and localize sounds; (4) utilization of speech-in-noise tests in pharmacotherapeutic clinical trials with considerations to the drug mechanistic action, the patient populations, and the study design; and (5) online and mobile applications of hearing assessment that increase accessibility and the direct-to-consumer market.

Newborn Incubators Do Not Protect from High Noise Levels in the Neonatal Intensive Care Unit and Are Relevant Noise Sources by Themselves

BACKGROUND

While meaningful sound exposure has been shown to be important for newborn development, an excess of noise can delay the proper development of the auditory cortex.

AIM

The aim of this study was to assess the acoustic environment of a preterm baby in an incubator on a newborn intensive care unit (NICU).

METHODS

An empty but running incubator (Giraffe Omnibed, GE Healthcare) was used to evaluate the incubator frequency response with 60 measurements. In addition, a full day and night period outside and inside the incubator at the NICU of the University Hospital Zurich was acoustically analyzed.

RESULTS

The fan construction inside the incubator generates noise in the frequency range of 1.3-1.5 kHz with a weighted sound pressure level (SPL) of 40.5 dB(A). The construction of the incubator narrows the transmitted frequency spectrum of sound entering the incubator to lower frequencies, but it does not attenuate transient noises such as alarms or opening and closing of cabinet doors substantially. Alarms, as generated by the monitors, the incubator, and additional devices, still pass to the newborn.

CONCLUSIONS

The incubator does protect only insufficiently from noise coming from the NICUThe transmitted frequency spectrum is changed, limiting the impact of NICU noise on the neonate, but also limiting the neonate's perception of voices. The incubator, in particular its fan, as well as alarms from patient monitors are major sources of noise. Further optimizations with regard to the sound exposure in the NICU, as well as studies on the role of the incubator as a source and modulator, are needed to meet the preterm infants' multi-sensory needs.