Call for calibration standard for newborn screening using auditory brainstem responses

Emerging Data from a Newborn Hearing Screening Program in Sharjah, United Arab Emirates

Objectives

Newborn hearing screening (NHS) plays a critical role in early identification of hearing loss and subsequent early habilitation. Active parental involvement influences the success of NHS, particularly the initial NHS and follow-up. The current study reports the results of an NHS program in a cohort of babies born in a tertiary care hospital in Sharjah, United Arab Emirates (UAE). Further, it explores a two-stage NHS model to reduce false responses, thereby alleviating parental anxiety.

Methods

Retrospective observational study was conducted for a period of five years from January 2017 to December 2020. NHS was done as a two-stage model. All the healthy newborn babies were screened using Automated Auditory Brainstem Response (AABR) by trained audiology professionals. Babies who failed the first NHS were followed up after two weeks. Further, babies that failed the follow-up NHS were sent for diagnostic hearing evaluation and intervention as necessary.

Results

A total of 1821 newborn babies were screened during the study period. Eighty-one percent of babies passed the initial NHS. Four hundred and twenty-three (23.22%) babies were referred on the first NHS and were followed up after 2 weeks. Among these babies, 7.03% (24) failed second NHS. Nine (37.50%) of the 24 babies were confirmed to have hearing loss in both ears. The incidence of hearing loss in our cohort was 4.94 per 1000. Confirmed hearing loss was statistically higher in boys than girls (p < 0.05).

Conclusion

Current study was an attempt to report the emerging NHS data as part of the implementation of an NHS program. The study findings emphasize the need for a two-stage model of NHS to rule out false responses.

Sensitivity of the Automated Auditory Brainstem Response in Neonatal Hearing Screening

BACKGROUND

In a 2-stage neonatal hearing screening protocol, if an infant fails the first-stage abstract screening with an otoacoustic emissions test, an automated auditory brainstem response (ABR)test is performed. The purpose of this study was to estimate the rate of hearing loss detected byfirst-stage otoacoustic emissions test but missed by second-stage automated ABR testing.

METHODS

The data of 17 078 infants who were born at Lis Maternity Hospital between January 2013 and June 2014 were reviewed. Infants who failed screening with a transient evoked otoacoustic emissions (TEOAE) test and infants admitted to the NICU for more than 5 days underwent screening with an automated ABR test at 45 decibel hearing level (dB HL). All infants who failed screening with TEOAE were referred to a follow-up evaluation at the hearing clinic.

RESULTS

Twenty-four percent of the infants who failed the TEOAE and passed the automated ABR hearing screening tests were eventually diagnosed with hearing loss by diagnostic ABR testing (22/90). They comprised 52% of all of the infants in the birth cohort who were diagnosed with permanent or persistent hearing loss .25 dB HL in 1 or both ears (22/42).Hearing loss .45 dB HL, which is considered to be in the range of moderate to profound severity, was diagnosed in 36% of the infants in this group (8/22), comprising 42% of the infants with hearing loss of this degree (8/19).

CONCLUSIONS

The sensitivity of the diverse response detection methods of automated ABR devices needs to be further empirically evaluated.

Prevalence of Hearing Loss in High Risk Infants of Mediocre Socio-economic Background at Around One Year of Age and Their Correlation with Risk Factors

The present study tried to determine the hearing threshold by brainstem evoked response audiometry (BERA) in the high-risk infants from a mediocre socio-economic background at around 1 year of age and correlate different risk factors with hearing loss. BERA was done on 127 infants of 6-18 months age of which 87 were high risk. All were given monaural acoustic stimulus using Cz-M1/M2 Montage. Based on the appearance of wave V at minimum stimulus intensity, hearing threshold in decibels (dB) of each ear was determined. To study the association of the individual risk factor with hearing loss multiple logistic regression test was applied. Taking BERA threshold for 'Pass' as ≤40 dBnHL, out of 87 high risk infants 10.34 % (n = 9) had bilateral severe to profound hearing loss, 17.24 % (n = 15) had bilateral mild to moderate hearing loss and 12.64 % (n = 11) had impaired hearing in one ear. All of the control group infants had normal hearing threshold of 30 dBnHL. Twenty major risk factors were identified in the whole study group at an average of 2.3 factors per infant. Twelve factors were examined for correlation using Odd's ratio (OR) with >40 dBnHL threshold as the outcome variable. Factors with very high OR were family history of deafness, Ototoxic drugs and Cranio-facial abnormality followed by others. High risk infants have a persistent and definitive risk of hearing loss prompting early intervention.