Newborn hearing screening (Queensland): Sensorineural hearing loss in preterm infants

What is it about?

The aim of this study was to compare newborn hearing screening, audiology assessment, hearing loss diagnosis, and timing of these events between infants in gestational age strata of <34 weeks, 34-36+6 weeks, 37-38+6 weeks, and ≥39 weeks. Early identification and management of sensorineural hearing loss (SNHL) in newborns, ideally by 3-6 months of age, facilitates speech and language optimisation. Literature stratifying hearing screening and diagnostic audiology assessment by gestational age groups is lacking. This analysis was performed to provide insight into the value of hearing screening in different gestational age groups. Method: Subjects were infants with recorded gestational ages receiving newborn hearing screening in Queensland between 2009-2011. Data were provided through the Queensland Healthy Hearing database, which screens >99% of Queensland's infants. Infants were analysed in <34 weeks, 34-36+6 weeks, 37-38+6 weeks, and ≥39 weeks gestational age groups. Results: 175,911 infants were eligible for analysis, 7.9% being preterm. Per 1,000 infants analysed, the majority of diagnoses of bilateral SNHL of ≥40 decibels occurred following direct referral at newborn hearing screen, with 2.1 for <34, 1.0 for 34-36+6, 0.7 for 37-38+6, and 0.6 for ≥39 weeks gestation. Comparatively, diagnoses per 1,000 infants following targeted surveillance occurred in 0.3 for <34, 0.4 for 34-36+6, and 0.0 for both 37-38+6 and ≥39 weeks gestation. Relative to term, preterm infants had a higher incidence of direct and targeted surveillance referrals, audiology assessment, and hearing loss diagnosis. Preterm infants were also screened later after birth. The median birth to screen interval was significantly higher in infants <34 weeks gestation (4.6 weeks) and 34-36+6 weeks (0.7 weeks) relative to term infants (0.3 weeks; p<0.001). The proportion receiving audiology assessment was significantly different between all gestational age groups, being highest in <34 week gestation infants (3.6% from direct refer, 25.3% TS, 1.3% for caregiver concern, 0.3% for medical exclusion) relative to 34-36+6 week infants (1.2%, 2.1%, 0.6%, and 0.1% respectively; p<0.001). Comparatively, 34-36+6 week infants represented a group with higher audiology assessment incidence than early term (37-38+6 week) and full term (≥39 week) gestational age groups, but only in regards to direct refer (p<0.05) and TS (p<0.001). Conclusions: Specific hearing screening and diagnosis characteristics differed between preterm infants <34 and 34-36+6 weeks gestation, and term infants. Consideration of unique gestational age strata characteristics supports care individualisation. Newborn Hearing Screening has been previously shown to be a highly valuable screening tool in pooled infants, with a majority of hearing loss diagnoses following newborn hearing screen direct referral (p<0.001). As the group with the highest incidence of hearing loss detection, the newborn hearing screen is of even greater relative utility in the <34 week and 34-36+6 week gestation groups.

Featured Image

Why is it important?

This retrospective state-wide Queensland study presents a comparison of hearing loss screening and detection between preterm and term infants. Findings provide insight into the expected differences and trends in hearing screening outcomes between gestational age groups. This paper demonstrates areas of significant difference between gestational age groups. Infants of the late preterm group were an intermediate group in regards to hearing screening characteristics and hearing loss patterns. This article is the foundation piece of a research series exploring the associations between specific risk factors and moderate or worse bilateral sensorineural hearing loss in preterm infants.