Newborn hearing screening by otoacoustic emissions and automated auditory brainstem response

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.

Determining concordance and cost impact of otoacoustic emission and automated auditory brainstem response in newborn hearing screening in a tertiary hospital

OBJECTIVE

This study compared otoacoustic emission (OAE) and automated auditory brainstem response (AABR) in terms of concordance and cost impact for newborn hearing screening (NBHS) in the Philippine setting.

METHODS

This was a prospective observational study to assess concordance between OAE and AABR involving 253 infants. Each infant underwent OAE and AABR testing. Infants who passed both tests were not required to follow up for additional testing. Infants who failed in any test were scheduled for repeat screening and diagnostic ABR after 1 month. Concordance was computed using B-statistic.

FOR COST ANALYSIS

4 scenarios were compared to 1-step both tests scenario: (1) OAE alone, (2) AABR alone, (3) 2-step OAE, and (4) 2-step AABR in terms of number of infants with hearing loss (HL) detected, cost of diagnosis, and economic loss from lack of treatment.

RESULTS

There was high concordance between OAE and AABR (B-statistic = 0.8). AABR had a higher refer rate (18.58%) than OAE (10.27%) but higher number of detected babies with HL. Cost analysis favored an AABR alone scenario while the 2-step OAE protocol fared poorly.

CONCLUSION

A change from 2-step OAE to AABR alone is worth considering in our institution.

Comparison of distortion product otoacoustic emission (DPOAE) and automated auditory brainstem response (AABR) for neonatal hearing screening in a hospital with high delivery rate

INTRODUCTION

Congenital hearing loss is one of the commonest congenital anomalies. Neonatal hearing screening aims to detect congenital hearing loss early and provide prompt intervention for better speech and language development. The two recommended methods for neonatal hearing screening are otoacoustic emission (OAE) and automated auditory brainstem response (AABR).

OBJECTIVE

To study the effectiveness of distortion product otoacoustic emission (DPOAE) and automated auditory brainstem response (AABR) as first screening tool among non-risk newborns in a hospital with high delivery rate.

METHOD

A total of 722 non-risk newborns (1444 ears) were screened with both DPOAE and AABR prior to discharge within one month. Babies who failed AABR were rescreened with AABR ± diagnostic auditory brainstem response tests within one month of age.

RESULTS

The pass rate for AABR (67.9%) was higher than DPOAE (50.1%). Both DPOAE and AABR pass rates improved significantly with increasing age (p-value<0.001). The highest pass rate for both DPOAE and AABR were between the age of 36-48 h, 73.1% and 84.2% respectively. The mean testing time for AABR (13.54 min ± 7.47) was significantly longer than DPOAE (3.52 min ± 1.87), with a p-value of <0.001.

CONCLUSIONS

OAE test is faster and easier than AABR, but with higher false positive rate. The most ideal hearing screening protocol should be tailored according to different centre.

The follow-up results of newborn hearing screening of Gaziosmanpasa Taksim Research and Training Hospital

Aim

This study aimed to present the results of newborns who were referred to advanced audiology centers after newborn hearing screening, and to determine concordance of our results with the American Academy of Pediatrics guidelines about the ages of hearing loss, aid fitting, and cochlear implantation.

Materials and Methods

A total of 7502 newborns were screened in Gaziosmanpaşa Taksim Research and Training Hospital between March 2014 and June 2016 using the transient otoacustic emissions test as the first two steps and automated auditory brainstem response test for the third step. Newborns who had risk factors were screened using the automated auditory brainstem response only. Newborns who failed the screening tests were referred to advanced audiology centers.

Results

Of the 7502 newborns, 6736 (90%) completed the screening. The ratio of hearing loss was 0.08%. Six of 62 newborns who failed auditory brainstem response test and were referred to advanced audiology centers had severe bilateral hearing loss. One of the patients was not fitted with a hearing aid because the family refused it. The other one was not fitted an aid and did not undergo cochlear implantation because of severe and treatment-resistant acute otitis media. The age of diagnosis for the rest was before three months, and except for one patient, hearing aid fitting was before six months. The age of cochlear implantation was 12 months for two patients and 14 months for two patients.

Conclusion

Ninety percent of patients completed the screening, the age of diagnosis for hearing loss was before three months and aid fitting was before six months, except for one patient. The results of the study were compatible with the diagnosis and treatment guidelines of the American Academy of Pediatrics.

Age and Other Factors Affecting the Outcome of AABR Screening in Neonates

BACKGROUND

Although the utility of universal newborn hearing screening is undisputed, testing protocols vary. In particular, the impact of the infant's age at the time of automated auditory brainstem response (AABR) screening has not been well studied.

METHODS

We conducted a retrospective review of newborn hearing screening data in 6817 low-risk, term and late-preterm newborns at our large, urban, academic medical center for a 1-year period to analyze the impact of age and other factors on the screening failure rate and referral for diagnostic testing.

RESULTS

AABR screening failure rates decreased with postnatal age over the first 48 hours; 13.3% failed at <24 hours versus 3.8% at ≥48 hours (P < .0001). Infants who were initially tested at ≥36 hours failed repeat testing more often than those who were tested at <36 hours (11.5% vs 18.9%; P = .03). Other factors that were associated with failure included being a boy and of a race other than white. Sensorineural hearing loss (SNHL) was diagnosed in 18.6% of infants who failed their final screening at ≥48 hours compared with 2.8% of those whose final screening occurred earlier (P = .03). SNHL was more likely in infants who failed their first screening bilaterally (21.2%) than unilaterally (4.4%); P = .03).

CONCLUSIONS

Among healthy newborns, delaying AABR screening in the first 48 hours minimized failure rates. SNHL was 6 times as likely in infants who failed their final screening at ≥48 hours compared with those who were screened at <48 hours of age. In our study, we offer guidance for nursery directors and audiologists who determine hearing screening protocols and counsel families about results.

Evaluation of universal newborn hearing screening in South African primary care

BACKGROUND

Universal Newborn Hearing Screening (UNHC) is the gold standard toward early hearing detection and intervention, hence the importance of its deliberation within the South African context.

AIM

To determine the feasibility of screening in low-risk neonates, using Otoacoustic Emissions (OAEs), within the Midwife Obstetric Unit (MOU) three-day assessment clinic at a Community Health Centre (CHC), at various test times following birth.

METHOD

Within a quantitative, prospective design, 272 neonates were included. Case history interviews, otoscopic examinations and Distortion Product OAEs (DPOAEs) screening were conducted at two sessions (within six hours and approximately three days after birth). Data were analysed via descriptive statistics.

RESULTS

Based on current staffing profile and practice, efficient and comprehensive screening is not successful within hours of birth, but is more so at the MOU three-day assessment clinic. Significantly higher numbers of infants were screened at session 2, with significantly less false-positive results. At session 1, only 38.1% of the neonates were screened, as opposed to more than 100% at session 2. Session 1 yielded an 82.1% rate of false positive findings, a rate that not only has important implications for the emotional well-being of the parents; but also for resource-stricken environments where expenditure has to be accounted for carefully.

CONCLUSION

Current findings highlight the importance of studying methodologies to ensure effective reach for hearing screening within the South African context. These findings argue for UNHS initiatives to include the MOU three-day assessment to ensure that a higher number of neonates are reached and confounding variables such as vernix have been eliminated.

Automatic quality assessment and peak identification of auditory brainstem responses with fitted parametric peaks

The recording of the auditory brainstem response (ABR) is used worldwide for hearing screening purposes. In this process, a precise estimation of the most relevant components is essential for an accurate interpretation of these signals. This evaluation is usually carried out subjectively by an audiologist. However, the use of automatic methods for this purpose is being encouraged nowadays in order to reduce human evaluation biases and ensure uniformity among test conditions, patients, and screening personnel. This article describes a new method that performs automatic quality assessment and identification of the peaks, the fitted parametric peaks (FPP). This method is based on the use of synthesized peaks that are adjusted to the ABR response. The FPP is validated, on one hand, by an analysis of amplitudes and latencies measured manually by an audiologist and automatically by the FPP method in ABR signals recorded at different stimulation rates; and on the other hand, contrasting the performance of the FPP method with the automatic evaluation techniques based on the correlation coefficient, FSP, and cross correlation with a predefined template waveform by comparing the automatic evaluations of the quality of these methods with subjective evaluations provided by five experienced evaluators on a set of ABR signals of different quality. The results of this study suggest (a) that the FPP method can be used to provide an accurate parameterization of the peaks in terms of amplitude, latency, and width, and (b) that the FPP remains as the method that best approaches the averaged subjective quality evaluation, as well as provides the best results in terms of sensitivity and specificity in ABR signals validation. The significance of these findings and the clinical value of the FPP method are highlighted on this paper.

Using a dynamic tracking filter to extract distortion-product otoacoustic emissions evoked with swept-tone signals

Distortion-product otoacoustic emissions (DPOAEs) are sound energy generated by healthy inner ears when stimulated by two tones. Since DPOAEs are physiologically related with the functional status of the inner ear, they have been widely used as a clinical tool in hearing screening and diagnoses. Currently, almost all DPOAEs recording systems use pure tones as the stimuli and can test only one frequency at a time, resulting in low efficiency and insufficient resolution. In this study, conventional pure tones were replaced by swept tones with time-varying frequencies to overcome the limitation of current DPOAEs measurements. A tracking filter with dynamic center frequencies was proposed to extract the swept-tone DPOAEs from recorded signals with stimulus artifacts and background noises. The results of this study showed that the dynamic tracking filter had great performance in effectively extracting the swept-tone DPOAEs under different noise conditions for both the simulation and experimental data. The spectrogram of the extracted swept-tone DPOAEs could provide useful information to examine the functional status of the inner ear and to identify the detailed frequency regions of the hearing loss. These preliminary findings suggested that the swept-tone DPOAEs might be useful for developing a more efficient and accurate tool for hearing loss screening in the clinic.

On the threshold of effective well infant nursery hearing screening in Western Sicily

OBJECTIVE

To determine the feasibility and effectiveness of well-infant nursery hearing screening programme for the early identification of hearing impairment, based on transient evoked otoacoustic emission (TEOAE) with a high "screen sensitivity" reducing the number of more expensive secondary level exams.

METHODS

The newborns were screened by non-specialist health workers in well babies nursery at the twentieth day of life for 6 years consecutive. Based on PASS/FAIL criteria and presence/absence of audiological risk factors the newborns were divided into four groups each one with its personal step programme: G1 - PASS without risk factor, free to go home; G2 - PASS with risk factor, retest at the age of 7 months; G3 - FAIL without risk factor, re-screening after 2 weeks for a maximum of four times before audiology assessment; G4 - FAIL with risk factor, retest after 2 weeks.

RESULTS

The coverage rate increased progressively from 89.8% to 92%. The referral rate was 1.51% after second stage with a specificity value of 98.78%. The four-stage screening performed for G3 reduced the numbers of global audiology assessment to 0.91% with a final global specificity of 99.4 ± 0.4%.

CONCLUSION

Less than 1% of infants underwent audiological assessment; the false positives resulted 0.62% with hearing loss global incidence of 2.95/1000 and a mean age of confirmation of 3.5 months of age. It is reasonable to think that this screening programme could be implement to overall 42 Western Sicily birth centres within few years.

Newborn hearing screening programme outcomes in a research hospital from Turkey

BACKGROUND

Universal neonatal hearing screening programmes are encouraged to define and manage hearing loss in early ages of life. The aim of this study is to introduce our 14-month three-step hearing screening programme results with 16 975 births in Turkey.

METHODS

In healthy neonates, Transient Evoked Otoacoustic Emission (TEOAE) is served as the initial screening in the first day of life. In newborns that did not meet pass criteria TEOAE was repeated in 10-day period. If the second test was 'refer' again, the screening was completed with auditory brainstem response (ABR). Additionally, ABR was performed for the neonates with neonatal intensive care unit (NICU) requirement and at high audiologic risk. Neonates who failed the screening test with ABR were referred for further evaluation.

RESULTS

A total of 15 323 newborns and 1652 NICU infants were tested. The screening coverage was 94.4%; 14 521 neonates (94.7%) passed the first screening step (TEOAE), while 802 (5.2%) neonate failed. In total, 322 (40.1%) of the neonates out of 802 was subjected to the second TEOAE after 10 days have failed and ABR was applied. From the neonates participated the third step (ABR) totalling 1974, 43 (2.17%) of neonates obtained a 'refer' response. Out of these 43 neonates, 17 neonates were (39.5%) NICU infants. From the 43 neonates, 38 cases (88.4%) were found to have hearing impairment. The false-positive rate for first step screening with TEOAE was 4.9%; second step with TEOAE was 1.85% and for ABR was 0.25%.

CONCLUSIONS

It is apparent that three step national hearing screening programme which has been applied for the latest years in Turkey is an accurate and non-invasive method to determine the congenital hearing loss. In the future, screening programmes could be rearranged with two steps as initial with TEOAE and retest with ABR and the coverage of the screening programme can be extended.

Análise crítica de três protocolos de triagem auditiva neonatal

TEMA: conhecer a validade dos procedimentos para triagem auditiva neonatal (TAN) é fundamental, visto que a meta desses programas é identificar todos os recém-nascidos com deficiência auditiva, com um custo aceitável. OBJETIVO: estimar a especificidade e taxa de falso-positivo de protocolos de TAN, realizados com emissões otoacústicas evocadas transientes (EOET) e potenciais evocados auditivos de tronco encefálico automático (PEATEa). MÉTODOS: 200 recém-nascidos foram submetidos à TAN entre março e julho de 2006. Foram analisados três protocolos: protocolo 1, TAN realizada em duas etapas com EOET; protocolo 2, TAN realizada em duas etapas com PEATEa; e protocolo 3, TAN realizada em uma etapa com dois procedimentos - teste com EOET seguido de reteste com PEATEa para os recém-nascidos que não passaram nas EOET. RESULTADOS: apesar de não ter havido diferença estatisticamente significante quando comparadas as taxas de encaminhamento para diagnóstico audiológico obtidos nos protocolos com EOAET e PEATEa, o protocolo com EOET encaminhou quatro vezes mais recém-nascidos. O protocolo 3 apresentou a maior taxa de encaminhamento, com diferença estatisticamente significante ao ser comparado com os protocolos 1 e 2. Conclusões: a taxa de falso-positivo e conseqüentemente a especificidade foram melhores no protocolo com PEATEa, seguido dos protocolos com EOET e com EOET e PEATEa.

Comparison of two-step transient evoked otoacoustic emissions (TEOAE) and automated auditory brainstem response (AABR) for universal newborn hearing screening programs

OBJECTIVE

Both transitory auditory otoemissions (TEOAE) and automated auditory brainstem responses (AABR) are considered adequate methods for universal hearing screening. The goal of this study was to compare the results obtained with each device, applying the same screening procedure.

MATERIALS AND METHODS

From 2001 to 2003, all the newborns in our health area (2454 infants) were evaluated with TEOAE (ILO92, otodynamics) and all those born from 2004 to 2006 (3117) were evaluated with AABR (AccuScreen, Fischer-Zoth). The population studied included all well newborns and those admitted to neonatal intensive care units (NICU). The first screening was normally undertaken with well babies during the first 48h of life, before hospital discharge. Infants referred from this first step underwent a second screening after hospital discharge, before they were a month old.

RESULTS

The results from each study group were compared and analyzed for significant differences. TEOAE screening yielded 10.2% fail results from the first screening step; AABR gave 2.6%. In the second screening step, 2% of the newborns screened with TEOAE were referred, whereas 0.32% of those screened with AABR were referred. These differences are statistically significant.

CONCLUSIONS

Although AABR screening tests involve a slightly higher cost in time and money than TEOAE, the results obtained compensate this difference. AABR gives fewer false positives and a lower referral rate; the percent of infants lost during follow-up is consequently smaller. Therefore, in our environment, universal newborn auditory screening with AABR is more effective than that with TEOAE.

Comparative evaluation of Transient Evoked Oto-acoustic Emissions and Brainstem Evoked Response Audiometry as screening modality for hearing impairment in neonates

OBJECTIVE

This study was designed to evaluate Transient Evoked Oto-acoustic Emission (TEOAE) as screening modality for hearing impairment in neonates. Brainstem Evoked Response Auditometry (BERA) was used as gold standard diagnostic tool in this study. The factors affecting the specificity of TEOAE were also studied.

METHODS

The study group of 200 randomly selected neonates was subjected to TEOAE and BERA (400 ears). Oto-endoscopy was done in all TEOAE failures and a repeat test was done after suction cleaning of blocked external auditory canal (EAC).

RESULTS

Otoscopic evaluation of all 52 TEOAE failures was done. EAC obstruction was noticed in 31 ears and 4 ears showed collapsible EAC. TEOAE was repeated after suction cleaning of the obstructed EAC and using long probe tips for collapsible EAC. This improved the Pass rate of TEOAE from 87% to 92%. EAC obstruction and collapsible EAC were the two factors identified in this study that significantly affected the specificity of TEOAE as a screening test. Pass rate of TEOAE in <48 hrs age group was found to be 55.5%, which was nearly half of over-all pass rate. This was because of high prevalence of obstructed EAC in this age group. TEOAE was found to be a rapid screening tool as average time taken for BERA was 35 min/neonate and for TEOAE was 17.4 min/neonate. Acceptability of TEOAE was found to be higher as compared to BERA.

CONCLUSIONS

TEOAE is a simple and rapid test with relatively higher acceptability. But, the low sensitivity and specificity are the main shortcomings that take away from TEOAE, the status of independent screening modality for hearing impairment in neonates. TEOAE cannot completely replace BERA as screening modality for hearing impairment in neonates, however can complement it.

Neonatal hearing screening: evaluation of tone-burst and click-evoked otoacoustic emission test criteria

OBJECTIVE

Click-evoked otoacoustic emissions (CEOAEs) are widely used in universal neonatal hearing screening programs. A common finding in many such programs is a relatively high false-positive rate. This is often due to infant physiological noise adversely affecting the emission recording, leading to a "refer" screening outcome. In an attempt to reduce false-positive screening outcomes related to the effects of noise on otoacoustic emission response detection, tone-burst-evoked otoacoustic emissions (TBOAEs) were included in a neonatal hearing screening program because TBOAEs may elicit a greater signal-to-noise ratio than CEOAEs. The research project compared the pass/refer rate for a CEOAE-based test using established pass/refer criteria with the pass/refer rate for screening criteria that were based on TBOAE results alone or on combined CEOAE and TEOAE results.

DESIGN

Neonates were recruited at the Hong Kong Adventist Hospital, and both CEOAEs and TBOAEs were performed. Six passing criteria were used in this study, based on CEOAEs only; CEOAEs plus 1 kHz TBOAEs; CEOAEs plus 2 kHz TBOAEs; CEOAEs plus 3 kHz TBOAEs; CEOAEs plus 1, 2, and 3 kHz TBOAEs; and TBOAEs only.

RESULTS

Data from 298 neonates (546 ears) were obtained. Criteria set 1, using CEOAEs only, demonstrated a pass rate of 79.1%, and 114 ears were referred. Criteria set 2, using CEOAEs together with TBOAEs recorded at 1 kHz, passed 39 more ears than Protocol 1, and the pass rate was 86.3%. Hence, the overall referral rate for total number of screened ears decreased by 7.2 percentage points. Criteria set 3, using CEOAEs together with TBOAEs recorded at 2 kHz, and Criteria set 4, using CEOAEs in conjunction with TBOAEs recorded at 3 kHz, gave pass rates similar to Criteria set 1. Criteria set 5, using TBOAE information at frequencies where CEOAEs were not rated as "pass," raised the pass rate from 79.1 to 87.6%, reducing the overall referral rate by 8.5 percentage points. Criteria set 6, in which neonates were screened with TBOAEs recorded at 1, 2, and 3 kHz, gave a pass rate of 78.4%, similar to results for the CEOAE-only procedure.

CONCLUSIONS

Both Criteria sets 2 and 5, which combined CEOAE and TBOAE recordings, gave significantly higher pass rates than Criteria sets 1, 3, 4, and 6. The results suggest that the introduction of combined CEOAE and TBOAE protocols may assist in the reduction of refer outcomes, and hence the false-positive rates, of neonatal hearing screening programs.

Hearing aid use in Finnish children--impact of hearing loss variables and detection delay

OBJECTIVE

The aim was to study the factors contributing to the mode of hearing aid use in children, with special emphasis on hearing loss variables and detection delay.

METHODS

The subjects were 328 children and adolescents (58.5% boys, 41.5% girls) aged 1-18 years with hearing loss of > or =30 dB HL in the better ear fitted with hearing aid(s). The study was cross-sectional analysing the mode of using the aid binaurally/unilaterally or not at all.

RESULTS

The children with hearing-impairment ranging from 50 to 90 dB HL used more regularly their hearing aids. In the subjects with hearing loss > or =80 dB HL the presence of measurable hearing threshold at 4 kHz related significantly to the acceptance of amplification (p=0.027). In 19% of the subjects hearing aid was discarded. Bilateral amplification was used in 38%. Unilateral use was the prevailing mode (44%). The younger the children (p=0.000) and the worse their hearing loss (p=0.008), the more regular their bilateral use was. Early detection of hearing loss and early hearing aid fitting promoted binaural hearing aid use (p=0.004). A marked asymmetry in pure tone thresholds was a significant audiological reason for fixed unilateral hearing device use (38%, p=0.001).

CONCLUSIONS

The study shows that early detection of hearing loss and early habilitation of hearing increase bilateral use of hearing device and decrease the number of nonusers. Furthermore, residual unaided hearing at 4 kHz significantly improves the use of device.

A Multisite Study to Examine the Efficacy of the Otoacoustic Emission/Automated Auditory Brainstem Response Newborn Hearing Screening Protocol

Purpose: This article examines whether changes in hearing screening practices are warranted based on the results of the recent series of studies by J. L. Johnson, K. R. White, J. E. Widen, J. S. Gravel, B. R. Vohr, M. James, T. Kennalley, A. B. Maxon, L. Spivak, M. Sullivan-Mahoney, Y. Weirather, and S. Meyer (Johnson, White, Widen, Gravel, James, et al., 2005; Johnson, White, Widen, Gravel, Vohr, et al., 2005; White et al., 2005; Widen et al., 2005) that found a significant number of infants who passed an automated auditory brainstem response (A-ABR) screening after failing an initial otoacoustic emission (OAE) screening later were found to have permanent hearing loss in one or both ears.

Method: Similar to the approach used by F. H. Bess and J. Paradise (1994), this article addresses the public health tenets that need to be in place before screening programs, or in this case, a change in screening practice (use of a 2-step screening protocol) can be justified.

Results: There are no data to suggest that a 2-step OAE/A-ABR screening protocol should be avoided.

Conclusion: Research is needed before any change in public policy and practice surrounding current early hearing detection and intervention programs could be supported.

Initiators in processes leading to hearing loss identification in Finnish children

The objective was to examine processes leading to the diagnosis of hearing loss in children. The subjects were 328 children (hearing loss >30 dB HL) fitted with hearing aids in Helsinki University Central Hospital. The risk factor initiated hearing loss detection in 31%, whereas parental suspicion accounted for 26% and hearing screening at the well-baby clinics for 20% of the subjects. Parents were foremost to suspect hearing loss at the age spoken language normally emerges (1.5-3.4 years). Screening was equally effective irrespective of the severity of hearing loss. Parents with misgivings of hearing impairment in their child should have compliant access to audiological units.

Control de las repeticiones en un programa de cribado auditivo universal

INTRODUCTION

To evaluate the influence of several factors in the need for retesting in the first stage of a universal auditory screening program, a prospective and statistic study is presented, specially remarking the differences found between two health systems (public and private).

PATIENTS AND METHODS

18,073 children born in the 1999-2004 period were included in the study, in the context of a universal screening protocol based on Otoacoustic emissions and ABR, and distributed into three groups depending on their place of birth (A: public hospital; B: private hospital; C: children from other region).

RESULTS

Significant differences were found between the groups (7.3% retesting in the public system and 2.4% in the private), explained by the fact that in the first group the test was performed in 74.9% of cases within 3 days after birth (when the need for repetition was 7,7%), and in the other groups the exploration was delayed up to 4-10 days in most cases (when retesting was performed only in 4.9%).

DISCUSSION AND CONCLUSIONS

Proportion of retesting in the first stage of a universal screening program is an important factor for the cost estimation of these protocols. We assume that the age at testing varies significantly this factor, and on the contrary, we know that precocious exploration (before the child leaves the hospital) increases the program covering. Therefore we conclude that the test should be delayed only in health systems needing to save resources or not able to test before discharge, and not in those wanting to guarantee the maximum covering.

A comparison of transient-evoked otoacoustic emissions and automated auditory brainstem responses for pre-discharge neonatal hearing screening

The aim of this study was to compare two hearing-screening methods in well newborn infants within the postnatal ward environment prior to discharge. Eighty-one newborn infants underwent one-step hearing screening by measurement of automated auditory brainstem responses (aABRs), using the ALGO-3 screener. These were compared with a further cohort of 81 neonates who underwent two-step screening using transient-evoked otoacoustic emissions (TEOAEs) followed by aABR. The pass rate was 78/81 (96.3%) for the one-step screen, 74/81 (91.4%) for the two-step screen, and 54/81 (66.7%) for TEOAE alone. There was no significant difference between cohorts in time required to complete the screening protocol. We conclude that pre-discharge hearing screening of newborn infants on the postnatal ward is feasible and acceptable. Use of TEOAE alone for pre-discharge screening is associated with an excessively high false-positive rate. At our institution, one-step screening resulted in a lower referral rate compared with a two-step approach. The performance of aABR screening may be affected by prior TEOAE screening.

A model of two-stage newborn hearing screening with automated auditory brainstem response

Our purpose was to evaluate a two-stage newborn hearing screening program using automated auditory brainstem response (AABR) before discharge and to describe our follow-up program. This study used 4085 infants born in the Seirei-Hamamatsu and Mikatahara General Hospitals during a 2-year period. The initial screening test was performed 2 or 3 days after birth at an intensity of 35 dBnHL. For the infants who were referred from this test, the re-screening test was performed 5 or 6 days after birth. Diagnostic work-up with auditory brainstem response (ABR), otoacoustic emissions (OAE), and a conditioned orientation reflex audiometry (COR) test were performed by the age of 3-6 months. The referral rate was 1.20% (49/4085 infants) in the first test and 0.71% (29/4085 infants) in the two-stage screening. The two-stage screening procedure was able to reduce the false-positive rate from 0.83 to 0.34%. The incidence of bilateral and unilateral congenital hearing loss diagnosed by ABR was 8/4085 (0.20%) infants and 7/4085 (0.17%) infants, respectively. One infant with congenital cytomegalovirus infection, who passed the two-stage AABR tests, was diagnosed with hearing loss 1 month after birth, using ABR. The two-stage measurement of AABR is effective and time efficient due to significant decreases in the referral rate and the false-positive rate.

Towards a universal newborn hearing screening

Hearing loss is a common problem which, if remaining undetected during early childhood, could affect the patient's linguistic and mental abilities permanently. Although recommended, mass hearing screening has so far been problematic or even impossible due to several reasons. The available otoacoustic emission devices appear to be effective tools for universal hearing screening. The aim of this study is to evaluate the reliability and practicability of a new device for recording click-evoked otoacoustic emissions (cEOEs) on a pediatric population. Sixty children aged between 6 days and 14 years were evaluated audiologically both by auditory brainstem responses (ABR) and otoacoustic emissions. The latter were obtained by using the well-known ILO88v3.92 otoacoustic analyser and a new, portable device ('Echocheck', Otodynamics Ltd, UK). Sensitivity and specificity of cEOEs recorded by 'Echocheck'was found to be 93% and 91%, respectively, when compared to ABR results. Additionally, 'Echocheck' recordings were proved to be much easier to perform, needing considerably less time in comparison with those of the ILO88 system. In our opinion, 'Echocheck' as well as all similar portable devices--screeners--may represent a much-desired solution for implementing universal hearing screening programmes.

Comparison of transient evoked otoacoustic emission thresholds recorded conventionally and using maximum length sequences

Presenting clicks according to maximum length sequences (MLSs) enables transient evoked otoacoustic emissions (TEOAEs) to be recorded at very high stimulation rates. Despite a decrease in TEOAE amplitude, the very large number of responses obtainable at high rates means that both signal to noise ratio (SNR) and detection sensitivity increase as the click rate increases. This study characterises conventional and MLS TEOAEs near threshold for a group of normally hearing adults. Stimulus presentation rates of 40 clicks/s (conventional) and 5000 clicks/s (MLS) were used. Compared to conventional recordings, the MLS technique enabled smaller responses to be detected, when averaged for the same time and to the same SNR. TEOAE amplitude recorded at detection threshold for MLS responses was 13 dB lower than that recorded conventionally. For each individual, MLS recording also produced clear, repeatable responses at stimulus levels below the detection threshold for conventional TEOAEs. The click level at TEOAE threshold was 12 dB lower for MLS compared to conventional emissions. These results suggest that TEOAE thresholds are not absolute but strongly related to the detection sensitivity of the recording system and physiological noise. The initial growth rates and the shape of input/output functions were found to be similar for the two recording techniques.

Outcome of newborn hearing screening by ABR compared with four different DPOAE pass criteria

The purpose of this study is to compare the effectiveness and utility of distortion product otoacoustic emission (DPOAE) and auditory brain stem response (ABR) testing as screening methodologies suitable for universal application at a large birthing hospital. Five hundred sixty-nine neonates (1184 ears) without risk indicators for hearing loss underwent DPOAE and ABR screening before hospital discharge at birth. All ears (100%) passed the ABR screening. DPOAE results were categorized on the basis of the number of frequencies at which emissions were obtained as well as presence versus absence of a replicated response at each test frequency. Pass and refer rates varied widely, on the basis of whether the presence of DPOAE response at 2000 Hz or replication were required. With the most stringent criteria, only 64.44% of ears passed, whereas with the least stringent criteria 88.94% passed. Given that 100% of ears passed according to the gold standard of the ABR screening, these results indicate false-positive rates ranging from 11% to 35% by DPOAE screening. This discrepancy in pass and refer rates when various criteria are applied indicates the need for standardization and further comparison of appropriate pass criteria for newborn hearing screening programs.

External and middle ear effects on infant hearing screening test results

This study investigated the relationship between external and middle ear factors and hearing screening results by automated auditory brain stem response (ABR) and transient-evoked otoacoustic emissions (EOAEs). The ears of 200 healthy newborns aged 5 to 48 hours underwent screening by ABR and EOAE, followed by otoscopic examination. The pass rates for ABR and EOAE were 91% and 58.5%, respectively. On otoscopic examination, 28% (112/400) ears had occluding vernix obscuring the view of the tympanic membrane. Cleaning of vernix was successfully performed in all but 2 ears that had occluding vernix. Cleaning of vernix significantly increased the pass rates of all 400 ears for ABR and EOAE to 96% and 69%. Decreased tympanic membrane mobility was found in 22.7% (90/396) of ears that were evaluated otoscopically. Decreased tympanic membrane mobility had a significant effect on EOAE screening; only 33.4% of ears passed EOAE testing. Decreased tympanic membrane mobility did not significantly affect pass rates for ABR screening; 95% of these ears passed the automated ABR screen. Implications for newborn hearing screening are discussed.

Hearing screening in healthy newborns: feasibility of different methods with regard to test time

Clicked-evoked otoacoustic emissions and automated auditory brainstem response are both considered appropriate hearing screening tools. The aim of this study was to compare their practicability with respect to test duration. In the first part of the study, clicked-evoked otoacoustic emissions were recorded in 388 healthy infants on the newborn ward in the first days of life. To reduce false positive rates of screening, clicked-evoked otoacoustic emissions combined with automated auditory brainstem response measurement (A-ABR, Algo 1E and Algo 2) were used in a second investigation. Fifty-five newborns screened by this two-stage method recorded an increased pass rate. The new digital technique of automated auditory brainstem response measurement (Algo 1E and Algo 2) employed in the second part of the study has a test time even shorter than that of clicked-evoked otoacoustic emissions and is no longer a time-consuming test due to improved technology of the second generation of automated auditory brainstem response equipment. Screening including preparation and follow-up time took 9.43 min (Algo 1E) and 8.26 min (Algo 2) respectively and was thus less time-consuming than reported in former studies.

Neonatal screening for hearing disorders in infants at risk: incidence, risk factors, and follow-up

OBJECTIVE

To determine the incidence and risk factors for hearing disorders in a selected group of neonates and the feasibility of selective hearing screening.

SETTINGS

Multicenter prospective trial at five centers in Germany.

METHODS

Enrollment criteria: in addition to previously defined risk factors by the Joint Committee on Infant Hearing (family history of hearing loss, in utero infections, craniofacial anomalies, birth weight <1500 g, critical hyperbilirubinemia, ototoxic medications, bacterial meningitis, postnatal asphyxia, mechanical ventilation >5 days, stigmata, or syndromes associated with hearing loss), the impact of maternal drug abuse, birth weight <10th percentile, persistent pulmonary hypertension, and intracranial hemorrhage more than or equal to grade III or periventricular leukomalacia on infant hearing were evaluated. The screening procedure was performed by automated auditory brainstem response (A-ABR; ALGO 1-plus; Natus Med Inc, San Carlos, CA).

STATISTICS

univariate analyses of risk factors versus A-ABR results and a multivariate regression analysis were used; additionally, the total test time was recorded.

RESULTS

Seven hundred seventy recordings from 777 infants enrolled consecutively constitute the basis of this analysis. Mean gestational age was 33.8 +/- 4.3 weeks, birth weight 2141 +/- 968 g; 431 infants being male and 339 female; 41 (5.3%) infants exhibited pathologic A-ABR results (16 bilateral and 25 unilateral). Meningitis or sepsis, craniofacial malformations, and familial hearing loss were independent significant risk factors. Median total test time was 25 minutes. Follow-up examinations in 31 infants revealed persistent hearing loss in 18 infants (13 infants sensorineural, 5 from mixed disorders), 7 requiring amplification.

CONCLUSION

Hearing screening in high-risk neonates revealed a total of 5% of infants with pathologic A-ABR (bilateral 2%). Significant risk factors were familial hearing loss, bacterial infections, and craniofacial abnormalities. Other perinatal complications did not significantly influence screening results indicating improved perinatal handling in a neonatal population at risk for hearing disorders.

Otoacoustic emission-based hearing screening of a Greek NICU population

The pressing need for early identification of hearing-disabled children has led to the development of several neonatal hearing screening programmes world-wide. Today otoacoustic emissions represent a widely used methodology for identification of neonatal hearing impairment. The purpose of the present study is to determine the sensitivity and specificity of click-evoked otoacoustic emissions (cEOAEs) in a Greek NICU population and compare the cEOAE data to the final hearing status of these children. A total of 438 ears of 223 neonates at high risk for hearing impairment were tested with both brainstem response audiometry (ABR) and cEOAEs. In 107 neonates the final hearing status was determined by using behavioural and playtone audiometry, at an age greater than 2 1/2 years. The sensitivity and specificity of the cEOAEs were found to be 90 and 92.4% when compared to ABR results and 90.9 and 91.1% when compared to the children's hearing status, respectively. Click-EOAEs have been proved to be highly effective in determining whether or not hearing impairment really exists. Since conventional ABR does not meet the requirements for large scale screening programmes, the cEOAEs represent a reliable alternative.

Comparison of newborn hearing screening by transient otoacoustic emissions and auditory brainstem response using ALGO-2

The aim of this study is to compare pass rates for two different hearing screening methods in well newborns as a function of age. A previous study by this group compared click evoked otoacoustic emissions (EOAE) and automated auditory brainstem response (ABR) using the ALGO-1 infant hearing screener (Natus Medical, Foster City, CA). Since that study, a new generation automated ABR screener, the ALGO-2, has been developed. In this study, 232 ears in 116 healthy newborn infants aged 5-48 h were tested using the ALGO-2 screener and EOAE. Overall, 92% of ears passed the ABR, while 57% passed the EOAE screen. The ABR pass rate was higher than in the previous study, where 88.5% of ears passed the ABR screen using ALGO-1. The EOAE pass rate in the present study was lower than in the previous study, in which 79% passed the EOAE screen. Pass rates for both EOAE and ABR improved significantly with increasing infant age. There was no significant difference in the test time required for ALGO-2 (5.7 min) compared with EOAE (5.2 min). The results are compared with earlier studies and implications for universal hearing screening are discussed.