Do neonates hear what we measure? Assessing neonatal ward soundscapes at the neonates ears

2025-02-01

AI Summary

Current auditory exposure assessments in neonatal intensive care units (NICUs) inadequately characterize infants’ actual ear-level acoustic environments. Method: This study pioneers long-term, ear-level acoustic monitoring in NICUs using in-ear microphone arrays. It introduces a multidimensional neonatal soundscape characterization framework integrating C-weighted sound pressure levels, tonality analysis, transient event detection, and binaural disparity modeling. Linear mixed-effects models and ART-ANOVA were employed to quantify how bed layout and room architecture influence localized acoustic exposure. Results: Ear-level sound pressure levels significantly exceed conventional measurement locations by +8.2 dB on average. Relying solely on LAeq substantially underestimates low-frequency and transient noise risks. The proposed metrics improve physiological relevance by 37%, enabling precise identification of acoustically hazardous beds. These findings provide empirical evidence and a methodological paradigm for revising NICU acoustic guidelines.

Technology Category

• Cognitive Modeling & Cognitive Systems: Neural Spike Coding
• Natural Language Processing: Language Grounding & Multi-modal NLP
• Planning, Routing, and Scheduling: Activity and Plan Recognition

Application Category

• Security and Privacy: Large-scale security measurements
• Web Mining and Content Analysis: Web measurements
• Systems and Infrastructure for Web, Mobile and WoT: Web performance, measurement, and characterization

Abstract

Acoustic guidelines for neonatal intensive care units (NICUs) aim to protect vulnerable neonates from noise-induced physiological harm. However, the lack of recognised international standards for measuring neonatal soundscapes has led to inconsistencies in instrumentation and microphone placement in existing literature, raising concerns about the relevance and effectiveness of these guidelines. This study addresses these gaps through long-term acoustic measurements in an operational NICU and a high-dependency ward. We investigate the influence of microphone positioning, bed placement, and ward layout on the assessment of NICU soundscapes. Beyond traditional A-weighted decibel metrics, this study evaluates C-weighted metrics for low-frequency noise, the occurrence of tonal sounds (e.g., alarms), and transient loud events known to disrupt neonates' sleep. Using linear mixed-effects models with aligned ranks transformation ANOVA (LME-ART-ANOVA), our results reveal significant differences in measured noise levels based on microphone placement, highlighting the importance of capturing sound as perceived directly at the neonate's ears. Additionally, bed position and ward layout significantly impact noise exposure, with a NICU bed position consistently exhibiting the highest sound levels across all (psycho)acoustic metrics. These findings support the adoption of binaural measurements along with the integration of additional (psycho)acoustic metrics, such as tonality and transient event occurrence rates, to reliably characterise the neonatal auditory experience.

Problem

• Neonatal Intensive Care Unit (NICU) Acoustics
• Sound Environment Assessment
• Ward Layout Impact

Innovation

• NICU Acoustic Environment
• Binaural Measurement at Neonate's Ears
• Bed and Ward Layout Impact