Comparison of currently available devices designed for newborn hearing screening using automated auditory brainstem and/or otoacoustic emission measurements

Universal newborn hearing screening program in Saudi Arabia: Current insight

Newborn hearing screening (NHS) programs are essential to identify hearing loss early in life and to improve outcomes in children. In Saudi Arabia, the national NHS program has been operational since 2016; however, few studies have evaluated its status, and none have covered all provinces across the country. This cross-sectional retrospective study provides an overview of the program's status across all provinces, focusing on screening coverage rates, referral/fail rates, and follow-up procedures. In 2021, 199,034 newborns were screened, with a coverage rate of 92.6% and an overall referral/fail rate of 1.87%. These performance measures provide a foundation for future progress and improvements. This study highlights the importance of ongoing efforts to enhance the program's effectiveness and sustainability.

Potential Destructive Binaural Interaction Effects in Auditory Steady-State Response Measurements

An aided sound-field auditory steady-state response (ASSR) has the potential to be used to objectively validate hearing-aid (HA) fittings in clinics. Each aided ear should ideally be tested independently, but it is suspected that binaural testing may be used by clinics to reduce test time. This study simulates dichotic ASSR sound-field conditions to examine the risk of making false judgments due to unchecked binaural effects. Unaided ASSRs were recorded with a clinical two-channel electroencephalography (EEG) system for 15 normal hearing subjects using a three-band CE-Chirp® stimulus. It was found that the noise corrected power of a response harmonic can be suppressed by up to 10 dB by introducing large interaural time differences equal to half the time period of the stimulus envelope, which may occur in unilateral HA users. These large interaural time differences also changed the expression of ASSR power across the scalp, resulting in dramatically altered topographies. This would lead to considerably lower measured response power and possibly nondetections, evidencing that even well fit HAs are fit poorly (false referral), whereas monaural ASSR tests would pass. No effect was found for simulated lateralizations of the stimulus, which is beneficial for a proposed aided ASSR approach. Full-scalp ASSR recordings match previously found 40 Hz topographies but demonstrate suppression of cortical ASSR sources when using stimuli in interaural envelope antiphase.

The Impact of Pass/Refer Criteria in the Use of Otoacoustic Emission Technology for Newborn Hearing Screening

Purpose The current study aimed to compare the specificity of transient evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) in isolation and in combination, with varying pass/refer criteria for DPOAE technology. Method A longitudinal, repeated-measures design was employed. The current study sample comprised 91 of the initial 325 participants who returned for the repeat screening and diagnostic audiological assessment within a risk-based newborn hearing screening program. Results TEOAE screening had the highest specificity in comparison to DPOAE screening at the initial and repeat screening, irrespective of differences in DPOAE pass/refer criteria. DPOAE screening had a slightly higher specificity, with a three out of six rather than the four out of six frequency pass criteria. Conclusions Pass/refer criteria alone do not influence referral rates and specificity. Instead, consideration of other factors in combination with these criteria is important. More research is required in terms of the sensitivity and specificity of OAE screening technology using repeated-measures and diagnostic audiological evaluation as the gold standard.

Cry features of healthy neonates who passed their newborn hearing screening vs. those who did not

OBJECTIVES

Temporal and fundamental frequency (fo) variations in infant cries provide critical insights into the maturity of vocal control and hearing performances. Earlier research has examined the use of vocalisation properties (in addition to hearing tests) to identify infants at risk of hearing impairment. The aim of this study was to determine whether such an approach could be suitable for neonates.

METHODS

To investigate this, we recruited 74 healthy neonates within their first week of life as our participants, assigning them to either a group that passed the ABR-based NHS (PG, N = 36) or a group that did not, but were diagnosed as normally hearing in follow-up check at 3 months of life, a so-called false-positive group (NPG, N = 36). Spontaneously uttered cries (N = 2330) were recorded and analysed quantitatively. The duration, minimum, maximum and mean fo, as well as two variability measures (fo range, fo sigma), were calculated for each cry utterance, averaged for individual neonates, and compared between the groups.

RESULTS

A multiple analysis of variance (MANOVA) revealed no significant effects. This confirms that cry features reflecting vocal control do not differ between healthy neonates with normal hearing, irrespective of the outcome of their initial NHS.

CONCLUSIONS

Healthy neonates who do not pass the NHS but are normal hearing in the follow-up (false positive cases) have the same cry properties as those with normal hearing who do. This is an essential prerequisite to justify the research strategy of incorporating vocal analysis into NHS to complement ABR measures in identifying hearing-impaired newborns.

Comparison between MB11 BERAphone® and ALGO2e color for hearing screening in Japanese healthy newborns

BACKGROUND

Since 2001, newborn hearing screening has been performed in Japan.

OBJECTIVE

This study compared newborn hearing screening results between the MAICO MB11 BERAphone (MB11) and the Natus ALGO2e color (ALGO) Automated Auditory Brainstem Response (AABR) devices among healthy Japanese newborns.

MATERIALS AND METHODS

From December 2014 to April 2018, 1477 healthy newborns were screened by MB11 and 267 by ALGO. Data from at-risk newborns were not included. Outcomes were 'Pass' and 'Refer' rates, specificity, false-positive rates, and assessment duration. Infants with a Refer result were examined using Interacoustics Eclipse.

RESULTS

MB11 identified 1425 (96.5%) as Pass and 52 (3.5%) as Refer. ALGO identified 263 (98.5%) as Pass and four (1.5%) as Refer. Specificity and false-positive rates were 97.7% and 2.3% for MB11 and 98.5% and 1.5% for ALGO, respectively. Using MB11, the total mean assessment time was 320.2 ± 220.7 s, with 315.6 ± 214.2 s for Pass and 628.6 ± 288.8 s for Refer.

CONCLUSIONS

MB11 is useful for hearing screening in healthy Japanese newborns and is fast and easy to operate. MB11 showed high specificity equivalent to ALGO.

Quality measures of a multicentre universal newborn hearing screening program in Malaysia

OBJECTIVE

To evaluate and discuss the outcomes of the universal newborn hearing screening program conducted at four public hospitals in Malaysia.

METHOD

A retrospective analysis of the universal newborn hearing screening database from each hospital was performed. The database consisted of 28,432 and 30,340 screening results of babies born in 2015 and 2016, respectively. Quality indicators (coverage rate, referral rate, return for follow-up rate, and ages at screening and diagnosis) were calculated.

RESULTS

Overall coverage rate across the four hospitals was 75% in 2015 and 87.4% in 2016. Over the two years, the referral rates for the first screening ranged from 2.7% to 33.93% with only one hospital achieving the recommended benchmark of <4% in both years. The return for follow-up rates for each participating hospital was generally below the recommended benchmark of ≥95%. The mean age at screening was 3.9 ± 1.2 days and 3.3 ± 0.4 days, respectively. The mean age at diagnosis for 70 infants diagnosed with permanent hearing loss was 4.7 ± 0.7 months in 2015 and 3.6 ± 0.9 months in 2016.

CONCLUSIONS

Quality measures for the universal newborn hearing screening program in four public hospitals in Malaysia were lower than the required standards. Nevertheless, some quality indicators showed statistically significant improvements over the two years. Next steps involve identifying and implementing the best practice strategies to improve the outcome measures and thus the quality of the program.

Screening Programs for Hearing Assessment in Newborns and Children

Objective In this study, we aimed to assess the incidence of hearing loss in the pediatric population through otoacoustic emission (OAE) and brainstem evoked response audiometry (BERA) and to analyze the possible etiological factors responsible for it. Material and methods A retrospective observational study was conducted in the Otolaryngology (ENT) and Gynecology and Obstetrics Departments at the Jinnah Postgraduate Medical Centre and National Institute of Child Health in Karachi, Pakistan between July 2019 and October 2019. The convenient sampling technique was used to select the patients. The final sample size consisting of newborns and children was 108. Initially, screening procedures were undertaken for newborns to detect permanent or fluctuating, bilateral or unilateral, and sensory or conductive hearing loss, averaging 30-40 dB or more in the frequency region, which indicated potential issues related to speech recognition (approximately 500-4,000 Hz). The screening of newborns involved the use of non-invasive, objective physiologic measures that included OAEs and/or auditory brainstem response (ABR). The children with hearing impairment then underwent BERA; thereafter, further investigations were performed to confirm the defects found on BERA testing. Results Of the 108 cases, 96 had normal hearing on OAE screening, and 12 were found to have hearing loss on the OAE test. Further testing was carried out on BERA for 12 cases that had been detected to have hearing loss on OAE, and BERA showed normal hearing for five cases whereas seven were found to have hearing loss. Of the seven patients with hearing loss on the BERA test, five were diagnosed with cochlear deafness, and two had retrocochlear deafness. Conclusion Our present study concludes that in order to avoid any hearing problems in infants, OAE hearing screening and diagnostic BERA screening programs should be carried out in all the hospitals of Pakistan to assess newborn hearing at an early age.

Electrophysiological exploration of hearing

Electrophysiologic hearing tests have been developed since the 1960s to determine hearing thresholds objectively. They are now implemented in newborn hearing screening. While they determine thresholds, interpretation requires subjective pure-tone and speech audiometry to determine the type of hearing loss. Each examination tests a different anatomic region, enabling the auditory system to be explored from the organ of Corti to the auditory cortex. Thus, the various objective audiometric examinations are complementary.

Feasibility of newborn hearing screening in a public hospital setting in South Africa: A pilot study

Objectives

The current pilot study aimed to explore the feasibility of newborn hearing screening (NHS) in a hospital setting with clinical significance for the implementation of NHS. Context-specific objectives included determining the average time required to screen each neonate or infant; the most suitable time for initial hearing screening in the wards; as well as the ambient noise levels in the wards and at the neonatal follow-up clinic where screening would be conducted.

Method

A descriptive, longitudinal, repeated measures, within-subjects design was employed. The pilot study comprised 11 participants who underwent hearing screening. Data were analysed using descriptive statistics.

Results

The average time taken to conduct hearing screening using otoacoustic emissions and automated auditory brainstem response was 18.4 minutes, with transient evoked otoacoustic emissions taking the least time. Ambient noise levels differed between wards and clinics with the sound level readings ranging between 50 dBA and 70 dBA. The most suitable screening time was found to be the afternoons, after feeding times.

Conclusion

Findings highlight important considerations when embarking on larger scale NHS studies or when planning a hospital NHS programme. Current findings suggest that NHS can be efficiently and effectively conducted in public sector hospitals in South Africa, provided that test time is considered in addition to sensitivity and specificity when deciding on a screening protocol; bar recognised personnel challenges.

Improving newborn hearing screening: Are automated auditory brainstem response ear inserts an effective option?

OBJECTIVE

Universal newborn hearing screening is an established practice among Hong Kong public hospitals using a 2-stage automated auditory brainstem response (AABR) screening protocol. To enhance overall efficiency without sacrificing program accuracy, cost reduction in terms of replacing the initial ear coupler-based screening with a more economical ear insert-based screening procedure was considered. This study examined the utility of an insert-based AABR initial screening approach and the projected cost-effectiveness of a combined probe-based plus follow-up ear coupler AABR screening procedure.

METHODS

Following prenatal maternal consent, newborn hearing screening was conducted with 167 healthy neonates using a cross-sectional, repeated measures study design. The neonates were screened with AABR sequentially; using ear coupler and ear probe (insert) procedures, in both ears, with two different but comparable AABR instruments. Testing took place in the antenatal ward of a department of obstetrics and gynaecology, at a large public hospital.

RESULTS

With the specific combination of instruments deployed for this study insert-based AABR screening generated a five-fold higher rescreen rate and took an additional 50% screening time compared to coupler-based AABR screening. Although the cost of consumables used in a 2-stage AABR screening protocol would reduce by 9.87% if the combined procedure was implemented, the findings indicated AABR screening when conducted with an ear probe has reduced utility compared with conventional ear coupler screening.

CONCLUSIONS

Significant differences may occur in screening outcomes when changes are made to coupler method. Initiating a 2-stage AABR screening protocol with an ear insert technique may be impracticable in newborn nurseries given the greater number of false positive cases generated by this approach in the present study and the increased time required to carry out an insert-based procedure.

Challenges of Implementing Universal Newborn Hearing Screening at a Tertiary Care Centre from India

OBJECTIVES

To report experience of implementing universal newborn hearing screening (UNHS) in a tertiary care neonatal unit, identify risk factors associated with failed two-step automated acoustic brainstem response (AABR) screen and evaluate cost of AABR.

METHODS

This was a prospective study of UNHS outcomes of all live births with two step AABR using BERAphone MB11®. Outcome measures were screening coverage, refer, pass and lost to follow up rates and cost of AABR using micro-costing method. To identify risk factors for failed screening, authors performed multivariate logistic regression with failed two-step AABR screen as dependent variable and baseline risk factors significant on univariate analysis as predictors.

RESULTS

Screening coverage was moderate (84 %), with 2265 of total 2700 eligible infants screened with initial AABR (mean gestation 37.2 ± 2.3 wk; birth weight 2694 ± 588 g; 305 received nursery care). A total of 273 of 2265 infants were "refer" on first screen. Second screen was done on 233, of which 58 were "refer". Of these, 35 underwent conventional ABR, of which 5 were diagnosed to have hearing impairment. Only 2 could get hearing aid. Overall, a total of 2197 (81.4 %) infants passed, 496 (18.4 %; excluding 2 deaths) were lost to follow up at various stages, and 5 (0.2 %) were diagnosed with hearing impairment, all of whom were high risk. Average cost of AABR was INR 276 per test. No factor emerged as significant on multivariate analysis.

CONCLUSIONS

UNHS is feasible to implement, but significant lost to follow up and non-linkage with appropriate rehabilitation services limit its utility. Cost effectiveness of UNHS compared to high risk based screening needs to be determined.

Outcomes with OAE and AABR screening in the first 48 h--Implications for newborn hearing screening in developing countries

OBJECTIVE

Early discharge of newborns (<24h after birth) from birthing centres is an important barrier to successful newborn hearing screening (NHS) in developing countries. This study evaluated the outcome of NHS within the first 48 h using an automated auditory brainstem response (AABR) device without the need for costly disposables typically required, and transient evoked otoacoustic emissions (TEOAE).

METHODS

NHS was performed on 150 healthy newborns (300 ears) with TEOAE and AABR techniques before discharge at a hospital. A three-stage screening protocol was implemented consisting of an initial screen with TEOAE (GSI AUDIOscreener+) and AABR (BERAphone(®) MB 11). Infants were screened at several time points as early as possible after birth. Infants were only re-screened if either screening technique (TEOAE or AABR) initially yielded a refer outcome. The same audiologist performed all TEOAE and AABR screenings.

RESULTS

Over the three-stage screen AABR had a significantly lower refer rate of 16.7% (24/144 subjects) compared to TEOAE (37.9%; 55/145 subjects). Screening refer rate showed a progressive decrease with increasing age. For both TEOAE and AABR, refer rate per ear screened 24h post birth was significantly lower than for those screened before 24h. For infants screened before 12h post birth, the AABR refer rate per ear (51.1%) was significantly lower than the TEOAE refer rate (68.9%). Overall AABR refer rate per ear was similar for infants screened between 24 to 36 h (20.2%) and 36 to 48 h (18.9%) but significantly lower than for TEOAE (40.7% and 41.9%, respectively). Lowest initial refer rates per ear (TEOAE 25.8%, AABR 3.2%) were obtained after 48 h post birth.

CONCLUSION

In light of the early post birth discharge typical in developing countries like South Africa, in-hospital screening with AABR technology is significantly more effective than TEOAEs. AABR screening with a device like the MB 11 is particularly appropriate because disposable costs are negligible.

The validity of family history as a risk factor in pediatric hearing loss

OBJECTIVES

A family history of permanent childhood hearing loss is considered a risk factor for pediatric hearing loss, although its validity has been sparsely examined. This study aimed to: (1) investigate the prevalence and yield of this risk factor for congenital and postnatal hearing losses, (2) define the audiometric characteristics of hearing loss in children with positive family histories, and (3) assess the nature of the familial relationships.

METHOD

A retrospective cohort study including all children born in Queensland, Australia between September 2004 and December 2011 who had completed Healthy Hearing's newborn hearing screen (n=380,895).

RESULTS

(1) Prevalence of the risk factor was 1.09% (4138/380,895). Prevalence of the risk factor in congenital cases was 7.29% and in postnatal cases was 36.84%. A low yield was identified for both congenital and postnatal groups (1.43% and 1.7%, respectively). (2) The degree of loss in congenital cases was highly varied, whereas the predominant degree in postnatal cases was mild. The most frequent type of loss for congenital cases was sensorineural, whereas for postnatal cases it was conductive. (3) Maternal or sibling relationships were most commonly reported for congenital losses, and maternal or paternal relationships for postnatal losses.

CONCLUSIONS

Children with a family history of pediatric hearing loss should have their hearing screened at birth and be monitored throughout early childhood. However, more efficient surveillance methods should be considered in view of the high prevalence with low yield.

Automated auditory brainstem response in preterm newborns with histological chorioamnionitis

OBJECTIVE

We investigated whether histological chorioamnionitis is associated with an adverse neonatal hearing outcome.

METHODS

Two cohorts of very preterm newborns (n = 548, gestational age ≤ 32.0 weeks) were linked to placental histology and automated auditory brainstem response (AABR) outcome.

RESULTS

In multivariable analyses, an abnormal AABR was not predicted by the presence of histological chorioamnionitis, either with or without fetal involvement (OR 1.4, 95% CI 0.5 - 3.8, p = 0.54 and OR 1.1, 95% CI 0.4-3.0, p = 0.79, respectively). Significant predictors of abnormal AABR included, e.g. birth weight (per kg increase: OR 0.2, 95% CI 0.0-0.6, p = 0.006), umbilical cord artery pH (per 0.1 increase: OR 0.7, 95% CI 0.5-0.9, p = 0.005) and mechanical ventilation (OR 3.7, 95% CI 1.2-11.6, p = 0.03).

CONCLUSIONS

Histological chorioamnionitis was not associated with an adverse neonatal hearing outcome in two cohorts of very preterm newborns. Indicators of a complicated neonatal clinical course were the most important predictors of an abnormal hearing screening.

Auditory screening in infants for early detection of permanent hearing loss in northern iran

Background:

Undiagnosed hearing loss can cause disorders in speech and language and delay in social and emotional development.

Aim:

This study aimed to screen for hearing loss in all newborns born in Babol city during 2009-2011.

Subjects and Methods:

Fifteen thousand one hundred and sixty-five newborns (49% [7430/15165] male and 51% [7735/15165] female) born during a 30-month period in Babol, underwent hearing screening by the otoacoustic emission (OAE) test at the age of 15 days. In infants referred at this stage, an auditory brainstem response (ABR) test was the next investigation. Data analyzed using Statistical Package for the Social Sciences software Version 16 (Chicago, IL, USA, 16) through descriptive statistic method.

Results:

In the first screening stage, 10.8% (1648/15165) cases were referred to the second stage for further investigation. 9.4% (154/1648) were lost to follow-up from among the referred cases despite continuous contact and education about the importance of the problem. Among the participants in the second stage, 6.2% (92/1494) were referred to the third stage and underwent ABR and OAE testing. 14.1% (13/92) were lost at this stage. Of the remaining participants, 34.2% (27/79) were diagnosed with a hearing loss. Therefore, the incidence of hearing loss in this study was 1.8/1,000 newborns.

Conclusion:

Given the prevalence of hearing loss in this study, implementation of a universal newborn hearing screening program is recommended.

Otoacoustic emissions in newborn hearing screening: a systematic review of the effects of different protocols on test outcomes

BACKGROUND AND OBJECTIVES

Otoacoustic emission (OAE) tests are currently used to screen newborns for congenital hearing loss in many Universal Newborn Hearing Screening programs. However, there are concerns about high referral and false-positive rates. Various protocols have been used to address this problem. The main objective of this review is to determine the effects of different screening protocols on the referral rates and positive predictive values (PPV) of the OAE newborn screening test.

METHODS

Eligible studies published in English from January 1990 until August 2012 were identified through searches of MEDLINE, Medline In-Process, Embase, PubMed (NCBI), ISI Web of Science, and the Cochrane Central Register of clinical controlled trials. Two reviewers independently screened the data sources, using pre-defined inclusion criteria to generate a list of eligible articles. Data extracted included the number of newborns screened, age at screening, OAE pass criteria, frequencies screened, number of retests, referral rates, and the number of newborns identified with permanent congenital hearing loss.

RESULTS

Ten articles met the inclusion criteria, with a total of 119,714 newborn participants. The pooled referral rate was 5.5%. Individual referral rates ranged from 1.3% to 39%; the PPV from 2 to 40%. Increasing the age at initial screening and performing retests reduced the referral rate. Likewise, screenings involving higher frequencies had lower referral rates.

CONCLUSION

Delaying newborn hearing screening improves test results but may not be practical in all contexts. The use of higher frequencies and more sophisticated OAE devices may be useful approaches to ensure better performance of the OAE test in newborn hearing screening.

Hearing screening using auditory steady state responses obtained by simultaneous air- and bone-conduction stimuli

INTRODUCTION AND OBJECTIVES

Minimising false positives rates is an important goal of universal newborn hearing screening programmes. An adequate way for reaching that goal could be differentiating between transient conductive hearing losses (false positives) and permanent sensorineural hearing impairments (true positives) by means of a methodology that studies electrophysiological responses obtained using both air- and bone-conduction stimuli. Our objective was to evaluate the efficiency of an automated hearing screening test based on auditory steady state responses obtained using simultaneous air- and bone-conduction stimuli.

METHODS

A sample of 80 high risk babies lees than 2 months of born were screened using the automatic screening test. A confirmatory clinical and electrophysiological evaluation was used as the gold standard.

RESULTS

The estimated diagnostic efficiency of this screening test was equivalent (100% sensitivity and 97.7% specificity) to the efficiency reported for otoacoustic emissions and automated auditory brainstem responses. The introduction of bone conduction in the screening reduced the false positive rate from 13.3% to 2.2%. The test duration was 5.3 (± 1.9)min. In 34% of babies only one repetition of the test was needed to raising the result.

CONCLUSIONS

The screening test performed quite well in this initial clinical trial, differentiating transient conductive hearing losses from permanent neurosensory impairments and improving the diagnostic efficiency of auditory steady state responses.

Second stage of Universal Neonatal Hearing Screening - a way for diagnosis and beginning of proper treatment for infants with hearing loss

PURPOSE

To analyze retrospectively the results of hearing testing in infants at the second stage of the Polish Universal Neonatal Hearing Screening Program carried out in the Department of Otolaryngology at the Medical University of Warsaw.

MATERIAL/METHODS

A total of 351 infants referred to our Department for the second stage of UNHS were included in the study. There were 39.60% infants referred due to positive result of hearing screening at the first stage of the Program performed in neonatal units, 55.27% with negative screening but risk factors present, and 5.13% without any tests due to equipment failure in the maternity unit.

RESULTS

Risk factors were identified in 86.61% of the infants. The most frequent ones were hyperbilirubinemia (71.51%), premature birth (63.25%), and ototoxic medication (62.11%). Otoacoustic emission test showed fail results in 17.66% of the infants, and auditory brainstem responses confirmed hearing loss in 16.81%. Correlation between risk factors and confirmed hearing loss was found for hyperbilirubinemia, low birth weight, intensive therapy for at least 7 days, low Apgar scores, and craniofacial abnormalities.

CONCLUSIONS

The early identification of infants with hearing loss is essential for early intervention. Not only infants who fail the initial screening but also the ones with risk factors of hearing impairment should be referred to the centers that are capable of providing the necessary diagnostic services required for the second stage of the UNHSP. Those two steps are needed to both minimize the risk of overlooking a child with hearing loss and properly diagnose hearing impairment.

Aetiology of congenital hearing loss: a cohort review of 569 subjects

OBJECTIVE

Newborn hearing screening was implemented in Flanders about fifteen years ago. The aim of this study was to determine the aetiology of hearing loss detected by the Flemish screening programme.

METHODS

From 1997 to 2011, 569 neonates were referred to our tertiary referral centre after failed neonatal screening with Auditory Brainstem Responses. In case hearing loss (HL) was confirmed, further diagnostic testing was launched. A retrospective chart review was performed analysing the degree of HL, risk factor and aetiology.

RESULTS

Metabolic disorders (0.5%), infectious diseases (35.8%), congenital malformations (6.1%) and genetic abnormalities (19.8%), whether or not syndromic, were retained. In 35% of the subjects no obvious aetiology could be determined in the current study.

CONCLUSION

In contrast to the literature findings, this series shows a genetic syndromic cause in 80% of the genetic bilateral HL cases. On the other hand connexin positive diagnoses were mostly underrepresented in this study, showing the need for better screening.

Implementation and results of bedside hearing screening with automated auditory brainstem response in the neonatal intensive care unit

AIM

To evaluate implementation and results of neonatal hearing screening with automated auditory brainstem response (AABR) by bedside nurses in a single-centre neonatal intensive care unit (NICU).

METHODS

Retrospective review of charts of 2074 newborns admitted over a 4-year period.

RESULTS

One thousand eight hundred and 24 newborns (88%) were screened. A 'pass' result was obtained in 1761 patients (96.5%). From 63 infants with 'refer', 40 were tested with auditory brainstem response: in 28 hearing loss was confirmed. Three hundred and nine neonates were screened before postmenstrual age (PMA) of 34 weeks: 78% successfully passed the first test. Sixty-seven infants with 'refer' at the first test before PMA of 34 weeks were re-evaluated: 48 had normal hearing tests, 24 of whom still younger than 34 weeks. For 12 of 19 infants with 'refer' before 34 weeks, follow-up was available: in 7 hearing loss was confirmed.

CONCLUSION

Neonatal hearing screening with AABR can be easily performed by the bedside nurse in the NICU even in premature babies before 34 weeks PMA. A 'pass' result can be obtained in almost 80% of them; a 'refer' result at that age, however, must be interpreted cautiously, as false 'refer' occurred in 5/12 of these infants.

ABR-based newborn hearing screening with MB11 BERAphone® using an optimized chirp for acoustical stimulation

OBJECTIVE

At our center, the Maico MB11 BERAphone(®) device is used for newborn hearing screening based on Auditory Brainstem Responses (ABR). In 2006, an optimized chirp stimulus was implemented in the device to increase the reliability and quality of the screening method. In 2002, an automated response detection algorithm had been implemented. This study analyzes the screening results using the MB11 BERAphone(®) device with the implemented chirp stimulus and automated response detection method.

METHODS

The data presented were collected in the well-baby nursery as part of the newborn hearing screening program following a two stage screening protocol. To focus the study on the typical routine screening, data from at-risk babies were not included. Overall, data from 6866 babies (3604 males and 3262 females) screened from March 2006 to April 2011 were analyzed in this study.

RESULTS

Out of the 6866 babies screened, 6607 passed bilaterally prior to hospital discharge (defined as 1st stage in this hearing screening program). Therefore, the pre-discharge pass rate of the hearing screening with the MB11 BERAphone(®) device was 96.2%. The resulting referral rate was 3.8%. The median test time per ear (excluding time for preparation and data reporting) was 28s with a range of 15-112s (5-95th percentile). The number of infants referred for 2nd stage, post-discharge re-screening was 259. Of this group, 71 passed bilaterally and 188 failed the re-screening in one or both ears. Therefore, including both the pre-discharge and post-discharge screening results, the bilateral pass rate was 97.3% and 2.7% were referred for diagnostic evaluation. Diagnostic testing was performed on all of the 188 infants who were referred. Results showed that 47 of these babies had hearing loss. This equates to a positive predictive value for a refer result of 25%. The observed prevalence of hearing impairment in our population was 0.684%. Diagnostic results for 141 of the referred newborns proved that they had normal hearing. That is, 141 out of 6866 newborns had a false-positive result with the MB11 BERAphone(®) screening. Therefore, the device had a specificity of 97.9%. During the time period of this study, no baby who passed the hearing screening was later found to have hearing impairment, suggesting a sensitivity of 100%. However, due to the limited number of newborns and the short time period after screening for the more recently screened babies, a reliable estimate of the sensitivity cannot be yet made from our program statistics. The theoretical sensitivity of the MB 11 device is 99.9%.

CONCLUSIONS

The Maico MB11 BERAphone(®) is a reliable device for auditory brainstem response newborn hearing screening and it provides results within a very short time. Due to the implemented method for automatic detection of ABR, the use of the device does not require an experienced examiner, allowing it to be used by trained technicians in locations outside the department of audiology such as the well-baby nursery.

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.

Evaluation of wavelet techniques in rapid extraction of ABR variations from underlying EEG

The aim of this study is to analyse an effective wavelet method for denoising and tracking temporal variations of the auditory brainstem response (ABR). The rapid and accurate extraction of ABRs in clinical practice has numerous benefits, including reductions in clinical test times and potential long-term patient monitoring applications. One method of achieving rapid extraction is through the application of wavelet filtering which, according to earlier research, has shown potential in denoising signals with low signal-to-noise ratios. The research documented in this paper evaluates the application of three such wavelet approaches on a common set of ABR data collected from eight participants. We introduced the use of the latency-intensity curve of ABR wave V for performance evaluation of tracking temporal variations. The application of these methods to the ABR required establishing threshold functions and time windows as an integral part of the research. Results revealed that the cyclic-shift-tree-denoising performed superior compared to other tested approaches. This required an ensemble of only 32 epochs to extract a fully featured ABR compared to the 1024 epochs with conventional ABR extraction based on linear moving time averaging.

A kernel-based novelty detection scheme for the ultra-fast detection of chirp evoked Auditory Brainstem Responses

Auditory Brainstem Responses (ABRs) are used as objective method for diagnostics and quantification of hearing loss. Many methods for automatic recognition of ABRs have been developed, but none of them include the individual measurement setup in the analysis. The purpose of this work was to design a fast recognition scheme for chirp-evoked ABRs that is adjusted to the individual measurement condition using spontaneous electroencephalographic activity (SA). For the classification, the kernel-based novelty detection scheme used features based on the inter-sweep instantaneous phase synchronization as well as energy and entropy relations in the time-frequency domain. This method provided SA discrimination from stimulations above the hearing threshold with a minimum number of sweeps, i.e., 200 individual responses. It is concluded that the proposed paradigm, processing procedures and stimulation techniques improve the detection of ABRs in terms of the degree of objectivity, i.e., automation of procedure, and measurement time.

Binaural measurement of bone conduction click evoked otoacoustic emissions in adults and infants

Transient evoked otoacoustic emissions (TEOAEs) are usually evoked with air conduction (AC) stimuli. Only a few reports exist about OAEs where stimuli have been delivered using bone conduction (BC) by placing a bone conductor on the forehead or the mastoid. The aims of the present study were to improve the test performance of BC-TEOAEs by using a nonlinear stimulation protocol and to find out, whether this technique can be applied in newborn hearing screening. BC-TEOAEs were measured binaurally in ten normal hearing adults and in ten infants. For measurements in infants, miniaturized probes without loudspeakers were constructed to allow a complete insertion of the probe in the infant's ear canal. It could be shown that robust and valid BC-TEOAEs can be elicited using a nonlinear stimulation protocol. Findings in adults indicated that BC-TEOAEs can be measured with properties similar to AC-TEOAEs. However, mean BC-TEOAE levels were reduced by 0.8-3.7 dB depending on frequency. In view of test time, this is compensated by performing binaural recordings. Measurements in infants indicated that the screening performance of BC-TEOAEs and AC-TEOAEs may be comparable. Further studies have to investigate, whether BC-TEOAEs are more robust than AC-TEOAEs against small conductive hearing loss.

[Newborn hearing screening test with multiple auditory steady-state responses]

INTRODUCTION

The techniques most frequently used within a screening context (otoacoustic emissions and click auditory brainstem response) have well-known limitations in hearing loss detection.

OBJECTIVE

This study examines the feasibility of a semi-automated multiple auditory steady-state responses (MSSR) system designed for neonatal hearing screening.

METHODS

A sample of 50 newborns without risk factors (well-babies) was tested within two weeks of birth. All had detectable auditory brainstem responses to clicks down to 40dB nHL in both ears. Two amplitude modulated carrier tones of 500 and 2,000Hz were mixed together and presented simultaneously. Each infant (and ear) was screened with the MSSR system; to simulate a hearing loss, a recording without stimulation was also obtained.

RESULTS

Mean auditory thresholds were 42.5±7dB HL at 500Hz and 35.5±6dB HL at 2,000Hz. The average duration of the MSSR recording was 2.6±1.6 minutes for each tested ear and the overall duration of the screening procedure (including electrode fitting and infant preparation) was 17.8±3.7 minutes. The diagnostic sensibility and the positive predictive values of the MSSR semi-automatic screening system was 100% and 96% respectively, with specificity of 96% and negative predictive values of 100%.

CONCLUSIONS

Although the diagnostic efficiency of the semi-automated MSSR system was found adequate, further technological improvements are still necessary to facilitate its use in the context of universal newborn hearing screening program.

Interdisciplinary approach to design, performance, and quality management in a multicenter newborn hearing screening project. Discussion of the results of newborn hearing screening in Hamburg (part II)

Previously presented results of the newborn hearing screening in Hamburg and the perspectives are subsequently discussed. Minimum standards referring a participation of 95% of the neonates and a fail rate of less than 4% hearing-impaired children at the primary screening are fulfilled in Hamburg. Systematic screening of newborn hearing by an interdisciplinary approach provides early identification and intervention for children with permanent unilateral and bilateral hearing loss. But a newborn hearing screening on a voluntary basis alone cannot be maintained in the long run. Further, an anonymous data collection is not sufficient in regard to an uninterrupted tracking of conspicuous and unscreened neonates. A lost-to-follow-up rate of 31.3% at primary screening in Hamburg is much too high and emphasizes the need for a public health approach to a population-based newborn hearing screening with an elaborate and name-based tracking system. The legislation and implementation of a nationwide newborn hearing screening program in Germany and the association of German newborn hearing screening centers are highlighting long efforts of hearing professionals. But the implementation of a newborn hearing screening only makes sense if there exists an efficient tracking system. Sad to say, we are still a long way from the implementation of such a tracking system.

MB11 BERAphone) hearing screening compared to ALGOportable in a Dutch NICU: a pilot study

OBJECTIVE

Since 2001 all Dutch Neonatal Intensive Care Units use a highly reliable automated auditory brainstem response (AABR) newborn hearing screening device, the (ALGOportable). A more recent AABR newborn hearing screening device, the MB11 BERAphone, does not make use of disposable ear couplers and has a different algorithm, a possible advantage with regard to a faster response acquisition. Use of the MB11 BERAphone is therefore potentially more cost effective and faster. This study compares test results and suitability of the MB11 BERAphone to the ALGOportable as reference AABR hearing screening test for newborns during neonatal intensive care admission.

METHODS

In 54 NICU graduates [median GA 31 2/7 weeks, median BW 1760 g] 55 (110 ears) hearing screening test results and total test time were examined with both the MB11 BERAphone and ALGOportable. Test time was measured from the start of the procedure, including child preparation, until a bilateral result (pass/refer) was obtained.

RESULTS

The median postconceptional age of testing was 34 3/7 weeks (range 30-41 6/7). In 3 ears MB11 BERAphone screening failed due to continuous myogenic activity. In 104/107 ears final results were congruent [87/107 (81%) pass; 17/107 (16%) refer] leaving an incongruity in 3 ears of 2 infants: MB11 BERAphone "refer" and ALGOportable "pass". Diagnostic investigative audiology confirmed a 35dB unilateral conductive hearing loss in 1 child. At 15 months of age speech and language development in the other child was normal. When using the ALGO portable as reference test, the sensitivity of the MB11 BERAphone is 100% (17/17), specificity 97% (87/90). The mean MB11 BERAphone test time was slightly, but not significantly, shorter 11.4 min (SD 6.6) than with the ALGOportable 13.9 (p<0.08).

CONCLUSION

The MB11 BERAphone is a reliable and feasible hearing screening device for use with NICU graduates under NICU circumstances. It is potentially more cost effective than the ALGOportable.

[Otoacoustic emissions in hearing screening in children]

BACKGROUND/AIM

Prevention of the consequences of hearing loss can be accomplished by early hearing screening of the cochlear function in newborus, but also with continuous hearing screening in the early childhood. The aim of this study was to investigate the reliability and feasibility of otoacoustic emissions (OAE) in hearing screening in children, evaluate the frequency and type of hearing loss and determine etiological factors of these losses.

METHODS

In the study, 133 children, aged 2 to 7.5 years, were tested on both ears with transient evoked otoacoustic emissions (TEOAE) and distortion-product otoacoustic emissions (DPOAE). Before screening tests all children had undergone otoscopic examination. If children had not passed either or both hearing screening tests and/or abnormal otoscopic findings in at least one ear, audiological evaluation was scheduled to confirm or exclude hearing loss.

RESULTS

Eighty-five percent of children passed the hearing and otoscopic screening bilaterally. For additional audiologic tests 15% of children were referred. Agreement between otoscopic examination and screening tests was very good (agreement for TEOAE 95%, for DPOAE 93%). The results showed that normal tympanograms were very likely to be associated with normal screening tests. Sensitivity of TEOAE test was 94.12%, specificity 78.95%, while DPOAE sensitivity was 87.50% and specificity 75%. Hearing loss was found in 6.76% of the cases, conductive in 6.01% and sensorineural in 0.75%. Conductive hearing loss was a consequence of chronic otitis media with effusion in 25% of the cases, and a consequence of adhesive process in the middle ear in 8.33% of cases. Sensorineural hearing loss was a consequence of using ototoxic medications.

CONCLUSION

TEOAE and/or DPOAE tests are reliable, noninvasive, and feasible methods for hearing screening in childhood.

Evaluation of an automated auditory brainstem response in a multi-stage infant hearing screening

An automated auditory brainstem response (AABR) method, the Maico MB-11 with BERAphone, has been developed for hearing screening in newborns. The aim of this study was to test the validity of this automated ABR screening method in a multistage newborn hearing screening (NHS). We applied a "five level" protocol using transient evoked otoacoustic emission (TEOAE), AABR-MB-11 with BERAphone and conventional auditory brainstem response (ABR). TEOAE, AABR, and conventional ABR testing were performed by ENT specialists experienced in neonatal screening techniques. Among the 8,671 newborns tested (males 3,889; females 4,782), only 42 newborns were lost to follow-up and the final false-positive rate was of 0.03%. Our experience highlights that for the neonatal period, conventional auditory brainstem response is the most reliable method for assessing the hearing level and minimizing the false-positive rate. Although AABR (performed by ENT specialists experienced in neonatal screening techniques) is easy to use, fast and with a good compliance, the device is unable to provide accurate and certain diagnosis on the degree of hearing loss to allow a proper treatment.

On the single sweep processing of auditory brainstem responses: click vs. chirp stimulations and active vs. passive electrodes

We have recently shown that click evoked auditory brainstem responses (ABRs) single sweeps can efficiently be processed by a hybrid novelty detection system. This approach allowed for the objective detection of hearing thresholds in a fraction of time of conventional schemes, making it appropriate for the efficient implementation of newborn hearing screening procedures. It is the objective of this study to evaluate whether this approach might further be improved by different stimulation paradigms and electrode settings. In particular, we evaluate chirp stimulations which compensate the basilar-membrane dispersion and active electrodes which are less sensitive to movements. This is the first study which is directed to a single sweep processing of chirp evoked ABRs. By concentrating on transparent features and a minimum number of adjustable parameters, we present an objective comparison of click vs.chirp stimulations and active vs. passive electrodes in the ultrafast ABR detection. We show that chirp evoked brainstem responses and active electrodes might improve the single sweeps analysis of ABRs.Consequently, we conclude that a single sweep processing of ABRs for the objective determination of hearing thresholds can further be improved by the use of optimized chirp stimulations and active electrodes.

Community-based infant hearing screening for early detection of permanent hearing loss in Lagos, Nigeria: a cross-sectional study

OBJECTIVE

To determine the feasibility and effectiveness of a community-based universal infant hearing screening programme for detecting permanent congenital and early-onset hearing loss (PCEHL) in Lagos, Nigeria.

METHODS

This is a cross-sectional study in which all infants aged 3 months or under attending four bacille Calmette-Guérin (BCG) immunization clinics accounting for over 75% of the BCG coverage in the study location were screened by community health workers between July 2005 and April 2006. Screening followed a two-stage protocol involving transient evoked otoacoustic emissions and automated auditory brainstem responses. The main outcome measures were screening coverage, referral rates, return rates for second-stage screening and evaluation, yield and age at PCEHL diagnosis.

FINDINGS

In total, 2003 (88%) of 2277 eligible infants attending the four BCG clinics were successfully screened between July 2005 and April 2006 at a mean age of 17.7 days, with no parent declining screening. The majority (55.2%) were born outside a hospital and, of such infants, 77% were born in traditional herbal maternity homes. The overall referral rate for diagnostic evaluation was 4.1%. Only 61% (50/82) of those referred returned for evaluation, and 45 of them were confirmed with PCEHL. Additionally, 11 infants who had previously passed the first screening stage were also found to have PCEHL, resulting in a yield of 28 per 1000 (56/2003). The mean age at diagnosis was 51 days. The sensitivity, specificity and positive predictive value of the first screening stage were 80.4%, 99.7% and 90.0%, respectively. The positive likelihood ratio was 268, while the negative likelihood ratio was 0.2.

CONCLUSION

Routine hearing screening of infants attending BCG immunization clinics by community health workers was feasible and effective for the early detection of PCEHL in Lagos, Nigeria. However, an efficient tracking and follow-up system is needed to improve return rates for second-stage screening and diagnostic evaluation.

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.

Hospital-based universal newborn hearing screening for early detection of permanent congenital hearing loss in Lagos, Nigeria

OBJECTIVE

To determine the feasibility and effectiveness of hospital-based universal newborn hearing screening programme for the early detection of permanent congenital or early-onset hearing loss (PCEHL) in Lagos, Nigeria.

METHODS

A cross-sectional pilot study based on a two-stage universal newborn hearing screening by non-specialist health workers using transient evoked otoacoustic emissions (TEOAE) and automated auditory brainstem-response (AABR) in an inner-city maternity hospital over a consecutive period of 40 weeks. The main outcome measures were the practicality of screening by non-specialist staff with minimal training, functionality of screening instruments in an inner-city environment, screening coverage, referral rate, return rate for diagnosis, yield of PCEHL and average age of PCEHL confirmation.

RESULTS

Universal hearing screening of newborns by non-specialist staff without prior audiological experience is feasible in an inner-city environment in Lagos after a training period of two-weeks. Notwithstanding excessive ambient noise within and outside the wards, it was possible to identify a test site for TEOAE screening within the hospital. The screening coverage was 98.7% (1330/1347) of all eligible newborns and the mean age of screening was 2.6 days. Forty-four babies out of the 1274 who completed the two-stage screening were referred yielding a referral rate of 3.5%. Only 16% (7/44) of babies scheduled for diagnostic evaluation returned and all were confirmed with hearing loss resulting in an incidence of 5.5 (7/1274) per 1000 live births or a programme yield of 5.3 (7/1330) per 1000. Six infants had bilateral hearing loss and the degree was severe (> or =70 dB nHL) in three infants, moderate (40 dB nHL) in one infant and mild (<40 dB nHL) in two infants. The age at diagnosis ranged from 46 days to 360 days and only two infants were diagnosed within 90 days.

CONCLUSIONS

Hospital-based universal hearing screening of newborns before discharge is feasible in Nigeria. Non-specialist staff are valuable in achieving a satisfactory referral rate with a two-stage screening protocol. However, a more efficient tracking and follow-up system is needed to improve the return rate for diagnosis and age of confirmation of hearing loss.

Neonatal hearing screening: a combined click evoked and tone burst otoacoustic emission approach

OBJECTIVE

This study evaluated an alternative transient evoked otoacoustic emissions method for screening hearing in newborn babies that may reduce the referral rate of initial screening.

METHODS

A total of 1,033 neonates (2,066 ears) from two hospitals were recruited. Subjects had their hearing screened in both ears using a combined approach-both click evoked OAEs (CEOAEs) and 1kHz tone burst evoked OAEs (TBOAEs).

RESULTS

1kHz TBOAEs were more robust than CEOAEs in terms of emission response level and signal-to-noise ratio (SNR) at both 1 and 1.5kHz frequency bands. The prevalence rate for CEOAE and TBOAE responses in these two frequency bands was significantly different. The combined protocol significantly reduced the referral rate-by almost 2 percentage points for first time screening.

CONCLUSIONS

The implementation of a combined 1kHz TBOAE/CEOAE screening protocol is a feasible and effective way to reduce referral rates, and hence false positive rates, in neonatal hearing screening programs.

Ultra-fast quantification of hearing loss by neural synchronization stabilities of auditory evoked brainstem activity

Recently, we proposed a new novelty detection paradigm for the fast detection of hearing thresholds using single sweeps of auditory evoked potentials as efficient approach to newborn hearing screening. Such a method might prevent currently used time consuming averaging procedures which require the state of spontaneous sleep, sedation, or narcosis of the newborns when using such systems in universal newborn hearing screening programs. In this study, we present an evaluation of new feature for such novelty detection schemes, namely the synchronization stability of auditory evoked brainstem activity. For this, large-scale correlates of the neural group synchronization at the brainstem for stimulation levels above the hearing threshold are detected as novel event. This novelty detection paradigm allows for the adaptive inclusion of individual measurement conditions using the spontaneous EEG. For the individual patient, at the challenging stimulation level of 30dB(HL) the synchronization stability allowed the discrimination of stimulated from the non-stimulated condition in a fraction of time of conventional devices. It is concluded that the proposed feature following the novelty detection paradigm might be used for the ultra-fast detection of hearing thresholds and is thus ideally suited for the use in efficient universal hearing screening programs.

MB11 BERAphone and auditory brainstem response in newborns at audiologic risk: comparison of results

OBJECTIVE

To compare the diagnostic effectiveness of Automated Auditory Brainstem Responses (MB11 technique) with that of standard Auditory Brainstem Responses (ABR) in a sample of newborns evaluated after the second month of life.

METHODS

From October 2002 to February 2005, audiologic evaluations were performed in full-term newborns who presented altered otoacoustic emissions and in newborns considered at audiologic risk admitted to the ENT (Ear Nose Throat) Unit of Giannina Gaslini Institute, Genoa, Italy. Our sample included 201 children (104 males and 97 females) who underwent on the same day an audiologic test using MB11 BERAphone Maico and standard ABR test.

RESULTS

Out of the 388 ears examined, 378 (97.4%) showed agreement between the two techniques, whereas in 10 (2.6%) there was no agreement. Interobserver agreement was excellent (kappa=0.92+/-0.02 S.E., p=0.0001). The MB11 test yielded no false negatives and 10 false positives which resulted normal at ABR. The MB11 test showed very good specificity 96.8% (95% CI 94.8-98.7%) and sensitivity 100% (95% CI 93.9-100%), positive predictive value 88.2% (95% CI 79-93.9%) and negative predictive value 100% (95% CI 98.4-100%) for diagnosis of hearing loss.

CONCLUSIONS

The results obtained confirm the absolute validity of MB11 screening test in subjects at audiologic risk. Furthermore, the test can be used to esclude normal hearing subjects (threshold 40 dB HL) and to refer hearing loss subjects to subsequent ABR for diagnosis.

The prevalence of congenital and early-onset hearing loss in Jordanian and Israeli infants

The objective of the study was to investigate the prevalence of congenital and early-onset hearing loss, and the influence of the known risk factors for hearing loss on infants in Jordan and Israel. Subjects were a total of nearly 17,000 infants from both countries, including infants with and without risk factors for hearing loss. The hearing screening protocol included distortion product otoacoustic emission, followed in case of repeated OAE referral or high risk (HR) infant by diagnostic auditory brainstem responses. The results indicate that the prevalence and severity of hearing loss amongst Jordanian infants (1.37%) is remarkably higher as compared to the Israeli infants (0.48%). The overall prevalence of bilateral SNHL was seven times more in the Jordanian infants, 18 times in non-risk, and three times in the HR infants relative to the Israeli infants. Risk factors including family history, hyperbilirubinemia, bacterial meningitis, and associated syndromes were more prevalent amongst Jordanian infants. This unique study underscores the importance of sharing and exchanging information to create empirical data to guide health-care providers in adapting protocols to the local constraints in developing countries.

Characteristic findings of auditory brainstem response and otoacoustic emission in the Bronx waltzer mouse

Auditory brainstem responses (ABRs) and distortion product otoacoustic emissions (DPOAEs) were evaluated serially from 1 to 22 months in Bronx waltzer homozygotes (bv/bv), heterozygotes (+/bv) and control (+/+) mice, which were differentiated by means of PCR of marker DNA (D5Mit209). The wave IV threshold of the click-evoked ABR was higher than the DPOAE threshold with the DP growth method in each bv/bv, although the two thresholds were almost the same in the +/+ group. The DP value at 2f(1) - f(2) in the bv/bv showed an apparent decrease at 2 to 3 months of age with 80 dB SPL stimulation using f(2) frequency 7996 Hz and frequency ratio f(2)/f(1) = 1.22, compared to control or heterozygote mice. It was characteristic that the 2f(2) - f(1) DP signal-to-noise ratio (SNR) value was more preserved from 80 to 60 dB SPL than the 2f(1) - f(2) DP value at f(2) frequency 7996 Hz in most bv/bv, however, control mice showed almost the same levels of 2f(1) - f(2) and 2f(2) - f(1) SNR value at both f(2) frequencies of 6006 and 7996 Hz. The preservation of a substantial 2f(2) - f(1) DP suggested that it would be generated basal to the primary-tone place on the basilar membrane and there might be a reflection of the unique function of the remaining outer hair cells in the Bronx waltzer mice. These findings suggest that combination of ABR with DPOAE could offer useful information about differentiating the mechanism of hair cell dysfunction of the hereditary hearing impairment in the clinical fields.

Automated pure-tone threshold estimations from extrapolated distortion product otoacoustic emission (DPOAE) input/output functions

A promising approach to the prediction of pure-tone thresholds through the estimation of DPOAE thresholds by input/output functions was recently published by Boege and Janssen [J. Acoust. Soc. Am. 111, 1810-1818 (2002)]. On the basis of their results, a device that enables automated measurements of these thresholds was recently developed. The purpose of the current study was to evaluate the reliability of this instrument for the objective assessment of hearing loss in 101 ears with either normal hearing or with cochlear hearing loss of up to 50 dB HL. The median difference between pure-tone hearing and DPOAE thresholds was approximately 2 dB. For individual subjects, however, DPOAE thresholds differed from pure-tone thresholds by up to 40 dB. We find, therefore, that the clinical benefits of this method are probably limited.