Infant sleep machines and hazardous sound pressure levels

Continuous white noise exposure during sleep and childhood development: A scoping review

BACKGROUND

White noise machines are widely used as a sleep aid for young children and may lead to poor hearing, speech, and learning outcomes if used incorrectly.

OBJECTIVE

Characterize the potential impact of chronic white noise exposure on early childhood development.

METHODS

Embase, Ovid MEDLINE, the Cochrane Central Register of Controlled Trials, Scopus, and Web of Science were searched from inception through June 2022 for publications addressing the effects of chronic noise exposure during sleep on early development in animals and children. PRISMA-ScR guidelines were followed. Among 644 retrieved publications, 20 met inclusion criteria after review by multiple authors. Seven studies evaluated animal models and 13 studies examined pediatric subjects, including 83 animal and 9428 human subjects.

RESULTS

White noise machines can exceed 91 dB on maximum volume, which exceeds the National Institute for Occupational Safety and Health noise exposure guidelines for a 2-h work shift in adults. Evidence suggests deleterious effects of continuous moderate-intensity white noise exposure on early development in animal models. Human subject data generally corroborates these models; however, studies also suggest low-intensity noise exposure may be beneficial during sleep.

CONCLUSIONS

Existing data support the limitation of maximal sound intensity and duration on commercially available white noise devices. Further research into the optimal intensity and duration of white noise exposure in children is needed.

The effects of white noise and swaddling methods on orogastric tube insertion-related pain in preterm infants: A randomized controlled trial

AIM

This study aims to investigate the effects of the white noise, swaddling and white noise + swaddling methods on pain and physiological parameters associated with orogastric tube insertion procedure.

METHODS

This was a randomized controlled trial. A total of 132 preterm infants were randomly assigned to four groups as white noise group (n = 33), swaddling group (n = 33), white noise + swaddling group (n = 33) and control group (n = 33). Interventions were initiated 5 min before the orogastric tube insertion procedure and continued during and up to 5 min after the procedure.

RESULTS

White noise intervention alone did not have a significant effect on reducing pain associated with orogastric tube insertion (p > 0.05). Compared with the control group, the preterm infants in the swaddling group experienced 0.587 times less pain, and those in the white noise + swaddling group experienced 0.473 times less pain.

CONCLUSIONS

Findings indicate the swaddling and the combination of white noise + swaddling may be a useful intervention in reducing the invasive pain experienced by preterm infants during and after orogastric tube insertion and in improving the physiological parameters associated with pain.

White noise use among children undergoing sound field audiometry: A preliminary study

OBJECTIVE

To describe the prevalence of routine white noise exposure in children who undergo sound field audiometry.

METHODS

A retrospective cohort study was conducted at a pediatric otolaryngology clinic affiliated with an academic tertiary care hospital. The medical records of children who underwent sound field audiometry were reviewed and data was collected regarding demographics and audiogram results. The group was divided into two cohorts based on routine exposure to white noise. Children exposed to white noise were tested with warble tones, while those not exposed were tested with narrow-band noise.

RESULTS

127 patients underwent sound field audiometry testing, of which 96 (75.6%) were reported by their parents to use white noise for sleep. The mean age at time of testing was 1.6 years (95% Confidence Interval [CI] 1.5-1.7). 104 (81.9%) children were able to respond to at least four of the sound field thresholds, and there was no significant difference between the children exposed to white noise and those who were not (P = 0.459). Mean pure tone average (PTA) was 26.2 dB (95% CI 25.2-27.2) and mean speech reception threshold (SRT) was 19.2 dB (95% CI 18.2-20.2). The sound field response rate, PTA, and SRT were similar between these two groups.

CONCLUSIONS

The routine use of white noise therapy was extremely common in this pediatric population. The use of warble tones as the audiometric stimuli for children exposed to white noise resulted in similar testing success compared to the use of narrow-band noise in children not exposed to white noise.

Preventing Excessive Noise Exposure in Infants, Children, and Adolescents

Noise affects people of all ages. Noise-induced hearing loss, a major problem for adults, is also a problem for young people. Sensorineural hearing loss is usually irreversible. Environmental noise, such as traffic noise, can affect learning, physiologic parameters, sleep, and quality of life. Children and adolescents have unique vulnerabilities. Infants and young children must rely on adults to remove them from noisy situations; children may not recognize hazardous noise exposures; teenagers often do not understand consequences of high exposure to music from personal listening devices or attending concerts and dances. Personal listening devices are increasingly used, even by small children. Environmental noise has disproportionate effects on underserved communities. This statement and its accompanying technical report review common sources and effects of noise as well as specific pediatric exposures. Because noise exposure often starts in infancy and effects are cumulative, more attention to noise in everyday activities is needed starting early in life. Pediatricians can potentially lessen harms by raising awareness of children's specific vulnerabilities to noise. Safer listening is possible. Noise exposure is underrecognized as a serious public health issue in the United States. Greater awareness of noise hazards is needed at a societal level.

Preventing Excessive Noise Exposure in Infants, Children, and Adolescents

Noise exposure is a major cause of hearing loss in adults. Yet, noise affects people of all ages, and noise-induced hearing loss is also a problem for young people. Sensorineural hearing loss caused by noise and other toxic exposures is usually irreversible. Environmental noise, such as traffic noise, can affect learning, physiologic parameters, and quality of life. Children and adolescents have unique vulnerabilities to noise. Children may be exposed beginning in NICUs and well-baby nurseries, at home, at school, in their neighborhoods, and in recreational settings. Personal listening devices are increasingly used, even by small children. Infants and young children cannot remove themselves from noisy situations and must rely on adults to do so, children may not recognize hazardous noise exposures, and teenagers generally do not understand the consequences of high exposure to music from personal listening devices or attending concerts and dances. Environmental noise exposure has disproportionate effects on underserved communities. In this report and the accompanying policy statement, common sources of noise and effects on hearing at different life stages are reviewed. Noise-abatement interventions in various settings are discussed. Because noise exposure often starts in infancy and its effects result mainly from cumulative exposure to loud noise over long periods of time, more attention is needed to its presence in everyday activities starting early in life. Listening to music and attending dances, concerts, and celebratory and other events are sources of joy, pleasure, and relaxation for many people. These situations, however, often result in potentially harmful noise exposures. Pediatricians can potentially lessen exposures, including promotion of safer listening, by raising awareness in parents, children, and teenagers. Noise exposure is underrecognized as a serious public health issue in the United States, with exposure limits enforceable only in workplaces and not for the general public, including children and adolescents. Greater awareness of noise hazards is needed at a societal level.

Improve sleep in critically ill patients: Study protocol for a randomized controlled trial for a multi-component intervention of environment control in the ICU

INTRODUCTION

In critically ill patients, sleep and circadian rhythms are greatly altered. These disturbances have been associated with adverse consequences, including increased mortality. Factors associated with the ICU environment, such as exposure to inadequate light and noise levels during the day and night or inflexible schedules of daily care activities, have been described as playing an essential role in sleep disturbances. The main objective of this study is to evaluate the impact of the use of a multifaceted environmental control intervention in the ICU on the quantity and quality of sleep, delirium, and post-intensive care neuropsychological impairment in critically ill patients.

METHODS

This is a prospective, parallel-group, randomized trial in 56 critically ill patients once they are starting to recover from their acute illness. Patients will be randomized to receive a multifaceted intervention of environmental control in the ICU (dynamic light therapy, auditory masking, and rationalization of ICU nocturnal patient care activities) or standard care. The protocol will be applied from enrollment until ICU discharge. Baseline parameters, light and noise levels, polysomnography and actigraphy, daily oscillation of plasma concentrations of Melatonin and Cortisol, and questionnaires for the qualitative evaluation of sleep, will be assessed during the study. In addition, all patients will undergo standardized follow-up before hospital discharge and at 6 months to evaluate neuropsychological impairment.

DISCUSSION

This study is the first randomized clinical trial in critically ill patients to evaluate the effect of a multicomponent, non-pharmacological environmental control intervention on sleep improvement in ICU patients. The results will provide data about the potential synergistic effects of a combined multi-component environmental intervention in ICU on outcomes in the ICU and long term, and the mechanism of action.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT. Registered on January 10, 2023. Last updated on 24 Jan 2023.

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.

Hazardous sound outputs of white noise devices intended for infants

OBJECTIVES

To measure the sound intensity of popular infant white noise machines and Apple iPhone applications (apps) as they vary with volume setting and distance, and compare these output levels with current National Institute for Occupational Safety and Health (NIOSH) noise exposure threshold recommendations.

METHODS

A total of eight infant white noise machines and six iPhone applications were included in the study based on product rating, number of ratings, and cost. The NIOSH Sound Level Meter application through the Apple App Store was used to measure output levels in A-weighted decibels (dBA). Each device was tested at its lowest and highest volume setting and at speaker-to-microphone distances simulating placement within a crib (10 cm), just outside of a crib rail (30 cm), and on a nightstand across the room (100 cm).

RESULTS

At the minimum volume setting, no device exceeded the NIOSH recommended noise exposure threshold of 85 dBA at any distance tested. At maximum volume setting, nine out of fourteen (64.3%) devices exceeded output levels of 85 dBA at a speaker-to-microphone distance of 10 cm. No device exceeded the recommended threshold at its maximal volume when placed 30 cm or 100 cm away.

CONCLUSION

Excessive white noise exposure has the potential to lead to noise-induced hearing loss and other adverse health effects in the neonatal and infant population. We recommend conservative use of white noise machines and apps by avoiding maximal volume setting and placing any device well outside of the crib or at least 30 cm away from the child. To promote safe use of white noise devices, future studies are needed to fully understand the association between early noise exposure and hearing loss in infants.

The Effect of Music and White Noise on Electroencephalographic (EEG) Functional Connectivity in Neonates in the Neonatal Intensive Care Unit

The purpose of this study is to investigate whether listening to music and white noise affects functional connectivity on scalp electroencephalography (EEG) in neonates in the neonatal intensive care unit.Nine neonates of ≥34 weeks' gestational age, who were already undergoing clinical continuous EEG monitoring in the neonatal intensive care unit, listened to lullaby-like music and white noise for 1 hour each separated by a 2-hour interval of no intervention. EEG segments during periods of music, white noise, and no intervention were band-pass filtered as delta (0.5-4 Hz), theta (4-8 Hz), lower alpha (8-10 Hz), upper alpha (10-13 Hz), beta (13-30 Hz), and gamma (30-45 Hz). Synchronization likelihood was used as a measure of connectivity between any 2 electrodes.In theta, lower alpha, and upper alpha frequency bands, the synchronization likelihood values yielded statistical significance with sound (music, white noise and no intervention) and with edge (between any 2 electrodes) factors. In theta, lower alpha, and upper alpha frequency bands, statistical significance was obtained between music and white noise (t = 3.12, 3.32, and 3.68, respectively; P < .017), and between white noise and no intervention (t = 4.51, 3.09, and 2.95, respectively, P < .017). However, there was no difference between music and no intervention.Although limited by a small sample size and the 1-time only auditory intervention, these preliminary results demonstrate the feasibility of EEG connectivity analyses even at bedside in neonates on continuous EEG monitoring in the neonatal intensive care unit. They also point to the possibility of detecting significant changes in functional connectivity related to the theta and alpha bands using auditory interventions.

On the Etiology of Listening Difficulties in Noise Despite Clinically Normal Audiograms

Many people with difficulties following conversations in noisy settings have “clinically normal” audiograms, that is, tone thresholds better than 20 dB HL from 0.1 to 8 kHz. This review summarizes the possible causes of such difficulties, and examines established as well as promising new psychoacoustic and electrophysiologic approaches to differentiate between them. Deficits at the level of the auditory periphery are possible even if thresholds remain around 0 dB HL, and become probable when they reach 10 to 20 dB HL. Extending the audiogram beyond 8 kHz can identify early signs of noise-induced trauma to the vulnerable basal turn of the cochlea, and might point to “hidden” losses at lower frequencies that could compromise speech reception in noise. Listening difficulties can also be a consequence of impaired central auditory processing, resulting from lesions affecting the auditory brainstem or cortex, or from abnormal patterns of sound input during developmental sensitive periods and even in adulthood. Such auditory processing disorders should be distinguished from (cognitive) linguistic deficits, and from problems with attention or working memory that may not be specific to the auditory modality. Improved diagnosis of the causes of listening difficulties in noise should lead to better treatment outcomes, by optimizing auditory training procedures to the specific deficits of individual patients, for example.

Brief report: sound output of infant humidifiers

The sound pressure levels (SPLs) of common infant humidifiers were determined to identify the likely sound exposure to infants and young children. This primary investigative research study was completed at a tertiary-level academic medical center otolaryngology and audiology laboratory. Five commercially available humidifiers were obtained from brick-and-mortar infant supply stores. Sound levels were measured at 20-, 100-, and 150-cm distances at all available humidifier settings. Two of 5 (40%) humidifiers tested had SPL readings greater than the recommended hospital infant nursery levels (50 dB) at distances up to 100 cm. In this preliminary study, it was demonstrated that humidifiers marketed for infant nurseries may produce appreciably high decibel levels. Further characterization of the effect of humidifier design on SPLs and further elucidation of ambient sound levels associated with hearing risk are necessary before definitive conclusions and recommendations can be made.