Thesis
Environmental noise and early language exposure in the neonatal intensive care unit
University of Iowa
Master of Science (MS), University of Iowa
Spring 2026
DOI: 10.25820/etd.008532
Abstract
Background: Infants born preterm (before 37 weeks) often spend the first weeks to months of life in the neonatal intensive care unit (NICU), where the auditory environment is vastly different
from the auditory environment in utero. These differences can affect early exposure to language
and environmental noise, which in turn may influence speech and language development.
Objective: This study examines and characterizes the auditory environment that infants
experience throughout their stay in a Level IV NICU focusing on both environmental noise (e.g.,
monitor alarms and respiratory equipment) and language (e.g., adult word count).
Study Design: Our study analyzed recordings from 30 preterm infants hospitalized in the NICU.
16-hour recordings were collected using a Language ENvironment Analysis (LENA) device on
one randomized day per week from study consent until NICU discharge. Group level
comparisons were used to examine how acuity level, bed type, and respiratory equipment
affected environmental noise and language exposure. Linear mixed-effects models then assessed
the influence of these factors on infants’ auditory environments while accounting for repeated
measurements and developmental age.
Results: All infants in this study experienced high levels of environmental noise (mean 56.4 dB
± 2.84; peak 94.3 dB ± 1.31), exceeding the 45 dB recommendation of the American Academy
of Pediatrics. Additionally, language exposure was low, with infants hearing an average of only
4,360 words per day (± 3,640) and much of the infant's time was spent in silence with an average
of 60.6% (± 26.5%) of the day in silence. When examining what factors affected the
environment, our study found that bed type, respiratory support, and room type all had
significant effects on the auditory environment.
Discussion: The NICU is not an optimal environment for early language development due to low
levels of meaningful language, high levels of environmental noise, and long periods of silence.
Our findings show that bed type, respiratory support, and room type significantly shape NICU
auditory environments. These findings highlight the need for purposeful improvement of this
environment to support language development, and the study identified areas of future
interventions.
Details
- Title: Subtitle
- Environmental noise and early language exposure in the neonatal intensive care unit
- Creators
- Maria Georgina Thurow
- Contributors
- Allison Momany (Advisor)Kristi Hendrickson (Advisor)Elizabeth Walker (Committee Member)Philip Combiths (Committee Member)
- Resource Type
- Thesis
- Degree Awarded
- Master of Science (MS), University of Iowa
- Degree in
- Speech and Hearing Science
- Date degree season
- Spring 2026
- DOI
- 10.25820/etd.008532
- Publisher
- University of Iowa
- Number of pages
- ix, 30 pages
- Copyright
- Copyright 2026 Maria Georgina Thurow
- Language
- English
- Date submitted
- 03/29/2026
- Description illustrations
- Illustrations, tables
- Description bibliographic
- Includes bibliographical references (pages 27-30).
- Public Abstract (ETD)
Background: Babies born preterm (<37 weeks) often spend their first weeks to months in the Neonatal Intensive Care Unit (NICU), where they experience different levels of language and noise than babies who are not hospitalized for extended periods.
Purpose: This study looked at how bed type, infant health status, and breathing support affects the sounds babies hear in the NICU. This study measured the percentage of the day spent in meaningful noise, environmental noise, and silence. It also measured the loudness and number of adult words.
Methods: Thirty preterm infants in the NICU had their auditory environment recorded once per week from when they joined the study until they went home. We examined how bed type, health status, and breathing support are related to the sound environment. Statistical models were used to account for differences over time.Results: Overall, infants in this study heard high levels of environmental noise, low levels of language, and were often in silence. Infants in cribs heard more adult speech and less environmental noise than infants in incubators. Greater medical needs and higher levels of breathing support were associated with more noise and less speech. Infants requiring less support heard more language and had more quiet periods.
Conclusions: Bed type, health status, and breathing support affect what infants hear in the NICU. Overall, the NICU has low levels of adult speech, high environmental noise, and long periods of quiet. These findings highlight the need to improve the sound environment in the NICU.
- Academic Unit
- Communication Sciences and Disorders
- Record Identifier
- 9985177274302771
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