Results of a 1-year government-funded newborn hearing screening program in Taiwan

Protocol and programme factors associated with referral and loss to follow-up from newborn hearing screening: a systematic review

BACKGROUND

An effective newborn hearing screening programme has low referral rate and low loss to follow-up (LTFU) rate after referral from initial screening. This systematic review identified studies evaluating the effect of protocol and programme factors on these two outcomes, including the screening method used and the infant group.

METHODS

Five databases were searched (latest: April 2021). Included studies reported original data from newborn hearing screening and described the target outcomes against a protocol or programme level factor. Studies were excluded if results were only available for one risk condition, for each ear, or for < 100 infants, or if methodological bias was observed. Included studies were evaluated for quality across three domains: sample, screening and outcome, using modified criteria from the Ottawa-Newcastle and QUADAS-2 scales. Findings from the included studies were synthesised in tables, figures and text.

RESULTS

Fifty-eight studies reported on referral rate, 8 on LTFU rate, and 35 on both. Only 15 studies defined LTFU. Substantial diversity in referral and LTFU rate was observed across studies. Twelve of fourteen studies that evaluated screening method showed lower referral rates with aABR compared to TEOAE for well babies (WB). Rescreening before hospital discharge and screening after 3 days of age reduced referral rates. Studies investigating LTFU reported lower rates for programmes that had audiologist involvement, did not require fees for step 2, were embedded in a larger regional or national programme, and scheduled follow-up in a location accessible to the families. In programmes with low overall LTFU, higher LTFU was observed for infants from the NICU compared to WB.

CONCLUSION

Although poor reporting and exclusion of non-English articles may limit the generalisability from this review, key influential factors for referral and LTFU rates were identified. Including aABR in WB screening can effectively reduce referral rates, but it is not the only solution. The reported referral and LTFU rates vary largely across studies, implying the contribution of several parameters identified in this review and the context in which the programme is performed. Extra attention should be paid to infants with higher risk for hearing impairment to ensure their return to follow-up.

Universal newborn hearing screening in South Africa: a single-centre study

Hearing screening for newborn babies is an established protocol in many high-income countries. Implementing such screening has yielded significant socioeconomic advantages at both an individual and societal level. This has yet to permeate low/middle-income countries (LMIC). Here, we illustrate how newborn hearing screening needs to be contextually adapted for effective utilisation and implementation in an LMIC. Specifically, this advocates the use of auditory brainstem testing as the first-line approach. We propose that such adaptation serves to maximise clinical efficacy and community participation at a reduced cost.

An effective compromise between cost and referral rate: A sequential hearing screening protocol using TEOAEs and AABRs for healthy newborns

OBJECTIVE

This study evaluated the efficacy of a sequential hearing screening protocol using transient evoked otoacoustic emission (TEOAE) and automated auditory brainstem response (AABR) tests in healthy newborns.

DESIGN

A TEOAE screening was performed during the first 48-72 h of life. If the infants failed, an AABR test was performed at the same time, and they were referred for a TEOAE rescreening at six weeks old. The results of screening Protocol 1 (only TEOAE) were compared with those of screening Protocol 2 (sequential TEOAE + AABR screenings for the first screening and TEOAE for the rescreening).

STUDY SAMPLE

A total of 1062 healthy newborns were enrolled in this research.

RESULTS

For Protocol 1, the first screening and rescreening referral rates were 11.1% and 2.2%, respectively. In contrast, for Protocol 2, the referral rates were significant lower at 3.8% and 0.9%, respectively. Using the two protocols, six infants were diagnosed with hearing loss (0.57%).

CONCLUSIONS

Adding simultaneous AABR tests for infants who fail TEOAE testing at the first screening stage can significantly reduce referral rates without increasing misdiagnosis rates. Although this sequential screening process involves slightly more time and has a higher cost than TEOAE alone, its greater accuracy compensates for this difference.

Government-funded universal newborn hearing screening and genetic analyses of deafness predisposing genes in Taiwan

OBJECTIVE

To investigate the association of eight connexin genes (GJB2, GJB4, GJA1P1, GJB6, GJB3, GJA1, GJB1, and GJC3) and the SLC26A4 gene with congenital hearing impairment among infants in a universal newborn hearing screening program.

METHOD

From September 2009 to October 2013, the consecutive neonates born in all six branches of Taipei City Hospital were enrolled. Infants who failed the newborn hearing screening and were diagnosed with hearing impairment underwent the genetic analyses.

RESULT

15,404 neonates were born at Taipei City Hospital, and 15,345 neonates underwent newborn hearing screening. Among them, 32 infants were diagnosed with unilateral or bilateral hearing impairment. 26 of them underwent analyses of the connexin genes and the SLC26A4 gene. Of the connexin genes, two infants carried a GJB3 mutation (heterozygous c.580G>A and heterozygous c.520G>A, respectively). Only one infant carried a GJB2 mutation (homozygous c.235delC). One infant carried a GJA1P1 mutation (heterozygous c.929delC) and another carried a GJB4 mutation (heterozygous c.302G>A). Additionally, one infant carried a GJA1P1 novel variant (heterozygous c.1081C>T). Another infant carried a GJA1 novel variant (heterozygous c.1-33C>G). Of the SLC26A4 gene, one infant carried heterozygous c.919-2A>G mutation and a novel variant (heterozygous c.164+1G>C), and high-resolution computed tomography (HRCT) of the temporal bone revealed bilateral enlarged vestibular aqueducts. One infant carried heterozygous c.919-2A>G mutation and no inner ear anomalies were demonstrated by HRCT of the temporal bone. Another infant carried a novel variant (heterozygous c.818C>T).

CONCLUSION

These results provide a genetic profile of the connexin genes and SLC26A4 gene among infants with hearing impairment detected by a universal newborn hearing screening program in Taiwan. Further studies and long-term follow up of this cohort are warranted to determine the pathogenicity of each variants and the long-term hearing consequence.