Prevalence and Determinants of Hearing Impairment in High-Risk Neonates: A Prospective Study Using Brainstem Evoked Response Audiometry in a Tertiary Care Setting

Abstract

Background: Neonatal hearing impairment is a significant cause of long-term neurodevelopmental disability. High-risk neonates have a substantially increased risk due to perinatal and postnatal factors.
Objective: To determine the prevalence of hearing impairment and identify associated risk factors among high-risk neonates using Brainstem Evoked Response Audiometry (BERA).
Methods: A prospective observational study was conducted over 12 months in a tertiary neonatal intensive care unit. A total of 515 high-risk neonates underwent a two-stage screening protocol using otoacoustic emissions (OAE) followed by confirmatory BERA. Statistical analysis included descriptive statistics, chi-square testing, and logistic regression.
Results: The prevalence of confirmed hearing impairment was 23.3 per 1,000 neonates, significantly higher than general neonatal populations. Prematurity, birth asphyxia, and hyperbilirubinemia were independently associated with hearing loss (p < 0.05).
Conclusion: High-risk neonates demonstrate a significantly increased prevalence of hearing impairment. Early screening using combined OAE and BERA protocols is essential for timely diagnosis and intervention.

Keywords:Neonatal hearing loss, BERA, High-risk neonates, NICU, OAE, Screening

Introduction

Auditory input during early life is critical for language, cognitive, and social development. Hearing impairment in neonates, if undetected, can lead to long-term neurodevelopmental delays. The global prevalence of permanent neonatal hearing impairment is estimated to be significantly higher among highrisk neonates compared to the general population [1]. High-risk neonates, particularly those admitted to neonatal intensive care units (NICUs), are more vulnerable due to multiple perinatal risk factors such as prematurity, birth asphyxia, and hyperbilirubinemia [2,3]. Universal newborn hearing screening programs have been recommended to ensure early detection and intervention [4,5]. Despite global recommendations, disparities exist in screening implementation, especially in developing and resource-limited settings [6,7]. This study aims to evaluate the prevalence and associated risk factors of hearing impairment among high-risk neonates using Brainstem Evoked Response Audiometry (BERA).

Aim

To determine the prevalence and determinants of hearing impairment among high-risk neonates using BERA.

Materials and Methods

This prospective observational study was conducted in a tertiary care neonatal unit over a period of 12 months. A total of 515 high-risk neonates were included based on predefined clinical criteria consistent with established screening protocols [4]. Initial screening was performed using Otoacoustic Emissions (OAE), followed by confirmatory testing using BERA for neonates who failed repeat screening. This two-stage protocol is widely accepted for neonatal hearing screening [8,4]. Statistical analysis was performed using standard methods, including chi-square testing and logistic regression, with significance set at p < 0.05.

Study Design

Prospective observational study..

Setting

Neonatal Intensive Care Unit (NICU), tertiary care hospital.

Duration

12 months.

Study Population

515 high-risk neonates.

Inclusion Criteria

a. Prematurity (<37 weeks)
b. Low birth weight (<2500 g)
c. Birth asphyxia
d. Hyperbilirubinemia requiring treatment
e. NICU stay ≥5 days
f. Exposure to ototoxic medications
g. Neonatal infections

Exclusion Criteria

a. Congenital ear malformations
b. Parental refusal

Screening Protocol

a. OAE within 48–72 hours
b. Repeat OAE after 2 weeks
c. BERA at ≤3 months for failures
This sequential protocol is widely validated for neonatal screening.

Statistical Analysis

a. SPSS version 26
b. Descriptive statistics
c. Chi-square test
d. Logistic regression
e. Significance: p < 0.05

Results

The overall prevalence of confirmed hearing impairment was 2.3% (23.3 per 1000 neonates), which is markedly higher than that reported in general neonatal populations [1]. A higher proportion of affected neonates were preterm and had associated perinatal complications. Similar findings have been reported in previous NICU-based studies [9-11]. Multivariate analysis demonstrated that prematurity, birth asphyxia, and hyperbilirubinemia were significant predictors of hearing impairment, consistent with established literature [2,12,13] (Table 1-3) (Figure 1).

Table 1:Baseline Characteristics.

Table 2:Screening Outcomes.

Table 3:Risk Factors (Multivariate Analysis).

Figure 1:Prevalence of Hearing Impairment.

Figure 1:

1. Comparison between general neonatal population and highrisk neonates
2. Prematurity was the most common risk factor, consistent with previous studies.

Figure 2:Neonatal Hearing Screening Cascade.

Figure 2:

1. Sequential screening outcomes using OAE followed by confirmatory BERA.
2. The overall prevalence of confirmed hearing impairment was 2.3% (23.3 per 1000 neonates).
3. A higher proportion of affected neonates were preterm and had a history of perinatal complications.
4. Statistically significant associations were observed for prematurity, birth asphyxia, and hyperbilirubinemia.

Figure 3:Risk Factors for Hearing Impairment.

Table 4:

Odds ratios of significant predictors identified through multivariate analysis. 95% Confidence Interval (CI) (Table 4).

Discussion

The present study demonstrates a significantly higher prevalence of hearing impairment among high-risk neonates compared to general populations, aligning with findings from prior systematic reviews and cohort studies [1,9]. Prematurity and birth asphyxia were identified as strong predictors, which is consistent with previous studies utilizing BERA-based screening [2,10]. These risk factors are known to affect auditory pathway development and neurological integrity [14]. Hyperbilirubinemia also showed a significant association, supporting earlier evidence of bilirubin-induced neurotoxicity affecting auditory pathways [12,15]. The findings of this study are consistent with multicenter prospective data and global epidemiological trends, which emphasize the importance of structured screening programs [6,7]. Early identification and intervention are crucial, as studies have demonstrated improved language and cognitive outcomes when hearing impairment is detected early [16,17]. This study provides region-specific evidence from a tertiary care NICU, contributing to the limited data available from similar healthcare settings.

Clinical Implications

a. Mandatory NICU hearing screening protocols
b. Early audiological intervention
c. Prevention of long-term disability

Limitations

a. Single-center study
b. Limited sample size
c. Follow-up constraints

Conclusion

Hearing impairment is significantly more prevalent among high-risk neonates. Implementation of systematic screening protocols using OAE and BERA facilitates early diagnosis and timely intervention, thereby improving long-term developmental outcomes [4,16,18-20].

Ethical Approval

Approved by Institutional Ethics Committee. Parental consent obtained.

Conflict of Interest

None.

Funding

None.

Acknowledgments

None.

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