Factors Predicting Subsequent Changes in Hearing Thresholds in Neonates with Initial Hearing Impairment

To investigate 6 month changes in hearing thresholds among neonates with hearing impairment and to explore potential factors associated with these changes.

This retrospective study was conducted from June 2016 to June 2024 at a regional hospital. It included neonates with auditory brainstem response (ABR) thresholds exceeding 25 dBnHL in diagnostic audiology tests. Exclusions were made for those with auditory neuropathy spectrum disorder, craniofacial anomalies, non-type A tympanograms, and those with only one recorded hearing evaluation at corrected ages of 1, 3, and 6 months. ABR thresholds and birth medical records were analyzed, categorizing cases into "hearing changed" and "hearing unchanged" groups based on changes in ABR thresholds.

The study included 96 neonates (154 ears), during the 6 month follow-up, hearing thresholds improved in 45 ears and worsened in 2 ears. Significant associations were found between sex (P = .002), birth weight (P = .020), gestational age (P = .002), care unit (P = .006). Multivariate analysis indicated that sex was the only significant predictor of ABR threshold changes. Decision-tree analysis revealed that male neonates transferred to the neonatal intensive care unit (NICU) as well as male neonates cared for in the baby room or with an unknown care unit and a birth weight <2.6 kg, were more likely to demonstrate improvement in hearing thresholds in 6 months.

Hearing thresholds in neonates with hearing impairment may improve over a 6 month follow-up period. These changes were associated with male sex, younger gestational age, lower birth weight, and postnatal transfer to NICU in univariate analyses; however, multivariate analysis identified sex as the only independent predictor. Given these findings, structured and ongoing audiological follow-up is crucial to facilitate early detection and timely intervention.