Neonatal hearing screening of high-risk infants using automated auditory brainstem response: a retrospective analysis of referral rates

Referral rate and false-positive rates in a hearing screening program among high-risk newborns

AIM

More studies exploring referral rates and false-positive rates are needed to make hearing screening programs in newborns better and cost-effective. Our aim was to study the referral and false-positivity rates among high-risk newborns in our hearing screening program and to analyze the factors potentially associated with false-positive hearing screening test results.

METHODS

A retrospective cohort study was done among the newborns hospitalized at a university hospital from January 2009 to December 2014 that underwent hearing screening with a two-staged AABR screening protocol. Referral rates and false-positivity rates were calculated and possible risk factors for false-positivity were analyzed.

RESULTS

4512 newborns were screened for hearing loss in the neonatology department. The referral rate for the two-staged AABR-only screening was 3.8% with false-positivity being 2.9%. Our study showed that the higher the birthweight or gestational age of the newborn, the lower the odds of the hearing screening results being false-positive, and the higher the chronological age of the infant at the time of screening, the higher the odds of the results being false-positive. Our study did not show a clear association between the mode of delivery or gender and false-positivity.

CONCLUSION

Among high-risk infants, prematurity and low-birthweight increased the rate of false-positivity in the hearing screening, and the chronological age at the time of the test seems to be significantly associated with false-positivity.

Results of a 10-year hearing screening using automated auditory brainstem response in newborns: The two-step AABR method

OBJECTIVES

Approximately 1-6 in every 1000 children are born with hearing loss. An automated auditory brainstem response (AABR) test is essential for screening newborns for abnormal hearing. At the tertiary hospital, we have been using a two-step AABR protocol for newborn hearing assessment since 2005. This study aimed to report the 10-year hearing screening results of newborns at the institution, and prove the efficacy of the two-step AABR protocol.

METHODS

From August 2005 to January 2015, 3059 newborns were screened through AABR testing using the MASTER ABaer system. The first screening test was performed after the first 24 h of life. If a newborn was referred, the test was performed within 1 month after discharge from the hospital. The results were regarded as pass when the point optimized variance ratio was >3.5, using a stimulus level of 35 dB HL. When newborns were referred for the second AABR, they received follow-up tests including tympanometry, ABR, auditory steady-state response, and otoacoustic emission within 3 months.

RESULTS

A total of 3059 newborns underwent newborn hearing screening tests over a period of 10 years. One hundred and twenty (3.9%) newborns were referred with the initial AABR, and 104 (3.4%) were referred with a subsequent AABR. Of the newborns, 42 (1.37%) were confirmed to have a bilateral hearing impairment.

CONCLUSIONS

It is known that the referral rate for the AABR test is 3-4%, as recommended by the Joint Committee on Infant Hearing. Our data showed a referral rate of 3.4%. The two-step AABR test has been useful for screening hearing loss in newborns at tertiary hospital.

Newborn hearing screening protocols and their outcomes: A systematic review

OBJECTIVE

To conduct a review of the most current research in objective measures used within newborn hearing screening protocols with the aim of exploring the actual protocols in terms of the types of measures used and their frequency of use within a protocol, as well as their outcomes in terms of sensitivity, specificity, false positives, and false negatives in different countries worldwide.

METHODS

A systematic literature review was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analysis. Electronic databases such as PubMed, Google Scholar and Science Direct were used for the literature search. A total of 422 articles were identified, of which only 15 formed part of the current study. The 15 articles that met the study's criteria were reviewed. Pertinent data and findings from the review were tabulated and qualitatively analysed under the following headings: country; objective screening and/or diagnostic measures; details of screening protocol; results (including false positive and negative findings, sensitivity and/or specificity), conclusion and/or recommendations. These tabulated findings were then discussed with conclusions and recommendations offered.

RESULTS

Findings reported in this paper are based on a qualitative rather than a quantitative analysis of the reviewed data. Generally, findings in this review revealed firstly, that there is a lack of uniformity in protocols adopted within newborn hearing screening. Secondly, many of the screening protocols reviewed consist of two or more tiers or stages, with transient evoked otoacoustic emissions (TEOAEs) and automated auditory brainstem response (AABR) being most commonly used. Thirdly, DPOAEs appear to be less commonly used when compared to TEOAEs. Lastly, a question around routine inclusion of AABR as part of the NHS protocol remains inconclusively answered.

CONCLUSIONS

There is sufficient evidence to suggest that the inclusion of AABR within a NHS programme is effective in achieving better hearing screening outcomes. The use of AABR in combination with OAEs within a test-battery approach or cross-check principle to screening is appropriate, but the inclusion of AABR to facilitate appropriate referral for diagnostic assessment needs to be systematically studied.

Outcomes of Automated Auditory Evoked Potential Performed in Different Settings and the Factors Associated with Referred Cases

Introduction  For the population with risk factors for hearing loss, the first option to assess the hearing status is the performance of the automated brainstem auditory evoked potential (BAEP) test because of its efficacy in identifying retrocochlear hearing loss. Objective  To verify the outcomes of automated BAEP performed in different settings as well as the factors associated with the prevalence of hearing impairment. Methods  Cross-sectional study conducted from October of 2014 to May of 2015. The sample consisted of 161 infants with at least one risk factor for hearing loss who underwent automated BAEP during the hospital stay or at the outpatient clinic. After 30 days, the altered cases were referred for BAEP diagnosis. Results  One hundred and thirty-eight infants (86%) had a result of "pass" and 23 (14%) of "failure" in the automated BAEP. There was no statistically significant difference in the rate of "referred" results between examinations performed in different settings. The infants' ages did not influence the number of abnormal cases. All of the 23 infants who presented a "referred" result in the automated BAEP, unilateral or bilateral, were sent for BAEP diagnosis, and out of these, 9 (39%) remained with at least some degree of alteration. The average age of diagnosis was 2.7 months. Conclusion  The results of the automated BAEP were similar when performed during hospitalization or after discharge. Neither the age at the examination nor the gender of the patient influenced the prevalence of hearing loss.