342 - Hearing impairment in very-low-birth-weight preterm infants: the performance of periodic hearing screening and potential risk factors

Publication Number: 342.5121

Kaiti Tseng, Mackay Children's Hospital, Taipei, Taipei, Taiwan (Republic of China)

Background: Preterm infants possess greater risks for hearing impairment and neurodevelopmental delay; prompt recognition of abnormal hearing and timely management are essential to limit the severity of potential disabilities. In order to diminish misclassification and delayed diagnosis of hearing impairment, our facility has long been incorporating tone-burst auditory brainstem response (TABR) test in infancy into the routine follow-up program for very-low-birth-weight (VLBW) infants, in addition to the universal newborn hearing screening (UNHS) using automated auditory brainstem response (AABR) performed during neonatal period.

Objective: The aims of our study were (1) to describe the sensitivity and specificity of the two screening tests done for VLBW infants – AABR before discharge and TABR at 6 months of corrected age, (2) to identify potential risk factors for hearing impairment in our VLBW cohort using accurate diagnostic data from the long-term otolaryngological follow-up.

Design/Methods: A retrospective cohort study was conducted at a tertiary neonatal intensive care unit, enrolling VLBW neonates between 2014 and 2018, who were followed for at least 2 years. Before discharge, all neonates received AABR as guided by the national program of UNHS. A TABR test was ordered at the outpatient visit scheduled at 6 months of corrected age for all VLBW infants as a periodic hearing screening. Those who did not pass either AABR or TABR, and those suspected of developmental delay, were referred to otolaryngology department, where behavioral pure-tone audiometry was performed to confirm the diagnosis. Sensitivity and specificity for both AABR and TABR were calculated in correlation with the longterm hearing outcomes. Multivariate regression models were used to analyze risk factors of hearing impairment originating in the perinatal and neonatal periods in this cohort.

Results: The follow-up rate for 359 VLBW neonates was 94.7%. Mean gestational age was 26.8 weeks. All neonates received AABR for neonatal hearing screening, and 95.6% had TABR performed at a corrected age of 6 months. 16.6% had at least one abnormal screening results. During follow-up, 6.5% had moderate-to-profound hearing impairment, and 3.2% wore hearing aids. TABR had higher area under the curve (0.92) to predict moderate-to-profound hearing loss. Vancomycin has a dose-dependent association with hearing loss. Other risk factors included small for gestational age, low first-minute Apgar score and prolonged membrane rupture.

Conclusion(s): TABR after discharge better identifies milder forms of hearing impairment in VLBW infants.

Sensitivity and specificity of AABR and TABR in predicting different categories of hearing impairment
In predicting hearing impairment, AABR had higher AUC value for prediction of hearing aid requirement during follow-up when compared to TABR performed at a corrected age 6 months (0.96 vs 0.90), but lower AUC value in predicting both abnormal pure-tone audiometry (0.78 vs 0.81) and moderate-to-profound hearing impairment (0.90 vs 0.91).
Abbreviations: automated auditory brainstem response (AABR); tone-burst auditory brainstem response (TABR); area under the (receiver operating characteristic) curve (AUC).

Perinatal and neonatal characteristics by abnormal hearing outcomes
Abbreviations: standard deviation (SD); gestational age (GA); small for gestational age (SGA); prolonged rupture of membrane (PROM); hemodynamically significant patent ductus arteriosus (HS PDA); intraventricular hemorrhage (IVH); periventricular leukomalacia (PVL); necrotizing enterocolitis (NEC).

Association between potential risk factors and moderate-to-profound hearing impairment
Abbreviations: small for gestational age (SGA); prolonged rupture of membrane (PROM)

Sensitivity and specificity of AABR and TABR in predicting different categories of hearing impairment
In predicting hearing impairment, AABR had higher AUC value for prediction of hearing aid requirement during follow-up when compared to TABR performed at a corrected age 6 months (0.96 vs 0.90), but lower AUC value in predicting both abnormal pure-tone audiometry (0.78 vs 0.81) and moderate-to-profound hearing impairment (0.90 vs 0.91).
Abbreviations: automated auditory brainstem response (AABR); tone-burst auditory brainstem response (TABR); area under the (receiver operating characteristic) curve (AUC).

Perinatal and neonatal characteristics by abnormal hearing outcomes
Abbreviations: standard deviation (SD); gestational age (GA); small for gestational age (SGA); prolonged rupture of membrane (PROM); hemodynamically significant patent ductus arteriosus (HS PDA); intraventricular hemorrhage (IVH); periventricular leukomalacia (PVL); necrotizing enterocolitis (NEC).

Association between potential risk factors and moderate-to-profound hearing impairment
Abbreviations: small for gestational age (SGA); prolonged rupture of membrane (PROM)