Neonatal hearing screening in a neonatal intensive care unit using distortion-product otoacoustic emissions

The Effects of Clinical Factors and Neonatal Morbidities on Hearing Screening among Neonatal Admissions

BACKGROUND

Hearing loss is an important disorder affecting newborns admitted to NICU. A national hearing screening program using otoacoustic emission testing is an essential tool to identify hearing loss early in neonates, enabling early intervention to avoid further challenges of pediatric deafness. On the other hand, a delay of the auditory pathway maturation in preterm babies compared to term newborns has already been suggested in the literature. Taking this information into account, in this paper, we aim to identify the best time to perform NICU infant hearing screening tests.

OBJECTIVES

We aim to study the clinical factors and neonatal morbidities that may affect neonatal hearing screening results using otoacoustic emission test in order to decrease the false-positive test results that increase parental anxiety and increase the need for subsequent investigations.

METHODS

This is a prospective cross-sectional study that included 204 infants who were admitted to a tertiary referral hospital NICU unit between September 2017 and May 2018. Both transients evoked otoacoustic emissions (TEOAE), and distortion product otoacoustic emission (DPOAE) screening tests were performed in order to screen hearing loss.

RESULTS

Our study included 204 infants, 52.9 % of which were males and 47.1 % females. There were correlations between both hyperbilirubinemia and ventilation ≥ 5 days and the failure rate of the first OAE test results among NICU infants where the P-values were (p=0.0133) and (p=0.0456), respectively. Moreover, 165 babies (80.9 %) passed the first OAE with a mean birth weight of 2759 gram and mean maternal age of 30.6 years, while 39 babies (19.1 %) failed the test with a mean birth weight of 2436 gram and a mean maternal age of 32 years. There was no statistically significant relation between both maternal age and birth weight with failure of the first screening test.

CONCLUSION

Our study suggests a higher failure rate of the first OAE in NICU infants who had hyperbilirubinemia or ventilation ≥ 5 days. Therefore, our recommendation is to postpone the first phase of hearing screening for those infants until the first scheduled vaccine appointment to achieve high compliance to attendance and decrease distress to the family that can be associated with false-negative results of the test.

[The hearing function in the premature children following their treatment with the use of ototoxic antibiotics]

The objective of the present study was the evaluation of the state of the auditory function in the premature children during the first year of life who underwent the neonatal treatment with various ototoxic antibiotics. A total of 232 newborn infants were available for the examination by the methods designed for recording distortion product optoacoustic emission (DPOAE) and short-latency auditory evoked potentials (SAEPs). The 'Statgraphics Centurion XV' program was used for the statistical treatment of the data obtained in the study. The results of recording DPOAE and SAEPs in 232 prematurely born children of different gestational age were used to evaluate their auditory function under conditions of treatment with various ototoxic antibiotics during the early neonatal period. It was shown that such treatment is likely to have an impact on the hearing function of premature children throughout the entire first year of life. Such influence can manifest itself as the enhanced threshold of the appearance of SAEPs peak V and the selective distortion of evoked responses recorded with the help of the DPOAE technique at a frequency of 4.6 kHz. It is concluded that all prematurely born children should be under observation of an otorhinolaryngologist-surdologist throughout the entire first year of life and, if appropriate, undergo the rehabilitative treatment at the earliest possible time. Moreover, the children with this condition must remain under the thorough follow-up care during at least 3 years including the yearly audiological evaluation and the comparative analysis of the results of previous observations for the timely identification of possible disturbances in the hearing function.

Effect of gentamicin on the auditory analyzer in sexually immature animals

Auditory function of immature rabbits was evaluated using two electrophysiological methods, brainstem auditory evoked response (BAER) and distortion product otoacoustic emission (DPOAE), in chronic experiments following administration of therapeutic doses of gentamicin. Impairment of auditory function manifested in increased thresholds and decreased amplitude of the 1st BAER peak was established. DPOAE parameters were not significantly changed. It was suggested that gentamicin decreased activity of spiral ganglion neurocytes in animals with immature auditory analyzer.

Prognostic validity of dichotic multiple frequencies auditory steady-state responses versus distortion product otoacoustic emissions in hearing screening of high risk neonates

OBJECTIVE

To determine the validity of dichotic multiple frequencies auditory steady-state responses (ASSR) as a hearing screening technique versus using distortion product otoacoustic emissions (DPOAEs) among high-risk neonates.

METHODS

A cross sectional study was performed on 118 high-risk neonates by means of dichotic multiple frequencies ASSR and DPOAE for hearing screening. DPOAE results were used as the standard for hearing screening in parallel with ASSR. Dichotic multiple frequencies ASSR results were analyzed by means of F-value of less or greater than 0.05 criteria as a pass-fail for the responses. Dichotic multiple ASSR hearing screening technique was considered in two intensity levels at 40 and 70 dB HL. The ASSRs thresholds were measured in high risk neonates with and without hearing deficits as determined by DPOAES. The results of ASSR and DPOAE were compared to be gathered by contingency table in order to obtain sensitivity, specificity and other different statistical values. Average performing times for the tests were analyzed.

RESULTS

The specificity of dichotic multiple ASSR was 92.6%, 93.8% and the sensitivity was 71.6%, 62.2% at the 70 and 40 dB hearing levels, respectively. Mean ASSR thresholds for normal-hearing infants at an average corrected age of 6 days were 32.2 ± 12.2, 29.8 ± 10.2, 26.2 ± 11.4 and 30.4 ± 10.8 dB HL for 0.5, 1, 2 and 4 kHz, respectively. The average times for performing the tests were 18.7 and 32.9 min respectively.

CONCLUSIONS

ASSR with this special paradigm is a fairly desirable method for hearing screening of high-risk neonates. There is good concordance between ASSRs and DOPAEs results among high risk neonates referred for hearing screening. The sensitivity and specificity of this test is sufficient for hearing screening in high risk neonates. This test could be valuable for rapid confirmation of normal thresholds. As long as further research have not been conducted on ASSR, great caution should be made to interpret the results of ASSR as a hearing screening technique in young infants and also additional techniques such as the tone-evoked ABRs should be used to cross-check results. It's still too soon to recommend ASSRs as a standalone electrophysiologic measure of hearing thresholds in infants.

Prevalence and Risk Factors of Hearing Impairment Among Primary-School Children in Shebin El-Kom District, Egypt

Purpose

This study examined the feasibility of screening hearing loss in rural and urban schools in Egypt, and investigated the prevalence and causes of hearing impairment (HI) in Egyptian primary-school students.

Method

A total of 555 children (6–12 years of age) from a rural and an urban school in the Shebin El-Kom District of Egypt were screened for HI at their schools. A 2-stage screening procedure was used, and positive cases were referred for a diagnostic hearing assessment at a regional medical facility. Risk factors were investigated through a parent questionnaire and an environmental study consisting of noise, ventilation, and crowding measurements at the schools.

Results

The screening failure rate was 25.6%, and the prevalence of confirmed HI was 20.9%. The rate of HI did not differ across the schools. Conductive hearing loss of minimal to mild severity was the most common type of HI. The most important predictors for HI were parent suspicion, otitis media, household smoking, low socioeconomic status, and postnatal jaundice.

Conclusions

The prevalence of HI did not differ across settings and was more common than reported in children from developed countries. The screening results also suggest that professionals with limited audiology background can be trained to implement hearing screening programs in Egyptian schools.

Correlation of hearing screening with developmental outcomes in infants over a 2-year period

CONCLUSION

Evoked otoacoustic emission (OAE) and auditory brainstem response (ABR) results for hearing screening among infants have good concordance. However, good correlation with the Griffiths Developmental Scales remains to be desired.

OBJECTIVE

To correlate hearing screening outcomes of a cohort of infants with developmental outcomes at 6 and 12 months.

SUBJECTS AND METHODS

A cohort of pregnant women was identified in several communities in a rural area (Bulacan province) from April 2002 to February 2003 as part of a population-based study determining maternal exposure to pollutants and infant outcomes, with a total follow-up of 2 years. Pregnant mothers were identified and followed up until delivery at a secondary, provincial hospital. Hearing screening was performed with OAEs and ABR. Mental development of infants was assessed at 6 and 12 months using Griffiths Mental Developmental Scales - locomotor, personal-social, hearing and speech, hand and eye coordination, performance tests.

RESULTS

Among the 1086 babies recruited, there were 724 with hearing assessment. Of these 724 babies, 565 had both OAE testing and ABR. Overall in 1130 ears, OAE and ABR testing showed an observed agreement of 99%, agreement due to chance of 96%, and kappa agreement of 79% (p=0.00) in diagnosing bilateral hearing losses. OAEs had a sensitivity of 86.4% (95% CI 64-96.4%) and a specificity of 99.4% (95% CI 98.6-99.7%). At the end of the study, there were 708/724 (97.8%) infants with normal hearing, 7/724 (1.0%) with unilateral hearing loss, 8/724 (1.1%) with bilateral mild hearing loss, and 1/724 (0.1%) with bilateral profound hearing loss, who demonstrated consistent mental delay throughout. Follow-up rates for developmental examinations at 6 and 12 months were 98% and 81.25%, respectively. In these groups, there were 8 (1%) infants at 6 months and 18 (2.4%) at 12 months with developmental delay (Griffiths Mental Developmental Scales).

Benefits and challenges of newborn hearing screening for developing countries

The late detection of permanent congenital and early-onset hearing loss (PCEHL) often has severe effects on linguistic, speech, cognitive and educational development in affected children. Since newborn hearing screening (NHS) allows most PCEHL to be detected early enough for optimal intervention, the prospects of its introduction in the developing world are reviewed in this paper. It is observed that a simple generalisation on the feasibility of NHS for the developing countries seems inappropriate in view of the diversities in the health and socio-economic status of these countries and the recent favourable reports of universal newborn hearing screening from the region. NHS empowers parents to make timely choices that will allow their hearing impaired children to be given a good start in life and be fully integrated into the wider community. It also compels attention towards the development of essential hearing healthcare services, besides the specific documented benefits. Existing child-healthcare structures such as the expanded programme on immunisation (EPI), baby friendly hospital initiatives (BFHI) and integrated management of childhood illness (IMCI) provide opportunities for the introduction of some form of NHS in many of these countries where routine or systematic childhood hearing screening does not exist. Limited funding, manpower shortages, inadequate support services, low public awareness and the uncertainty regarding the commitment from healthcare practitioners may present some challenges but these are not insurmountable. Pilot studies are necessary in each country to provide empirical data that will guide healthcare providers who wish to introduce such a programme at any level of healthcare delivery.

Otoacoustic emissions

PURPOSE OF REVIEW

Otoacoustic emissions offer the practitioner a number of beneficial features as a noninvasive and objective measure of the ear's ability to process acoustic stimuli.

RECENT FINDINGS

Since their discovery, a number of clinical applications of otoacoustic emissions have been established, including their utility in the differential diagnosis of sensorineural hearing loss, in the screening of cochlear function in infants and other difficult-to-test patients, and in the monitoring of outer hair cell healthiness in patients who are exposed to potentially damaging agents or who have progressive hearing ailments.

SUMMARY

Clinical applications of OAEs have developed very rapidly and OAEs have become the standard of care, at least, for pediatric patients.