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

Status of Newborn Hearing Screening Program in the State of Tamil Nadu, India

Newborn hearing screening in India is gaining momentum and more programs are getting established every year. We need to know their performance levels, strengths and weaknesses to provide suggestions for building effective future programs. The study aimed to report the status of Newborn Hearing Screening (NHS) program in the state of Tamil Nadu, India. A questionnaire on "Newborn Hearing Screening Survey" was developed and sent to 80 sites with NHS facility all over Tamil Nadu, India. The information collected was subjected to descriptive statistical analyses. On a 95% return rate, private sector contribution towards NHS program are the highest and most of the private hospitals have outsourced the NHS program. In most of the sites, audiologists are incharge of the NHS program and carried out the NHS testing. The majority of sites (67.1%) follow selective screening such as high risk factors, doctor's referral and admission at NICU. The preferred testing was TEOAE in the screening program. NHS protocol was found to be variable at each site and for each patient. The time between second screening and diagnostic testing went up to 3-6 months. However, there is a lack of organized system for documenting the program outcome. The result of this study calls the need for wider implementation of UNHS and to introduce a centralised state or local reporting system for documenting and tracking the infants with hearing impairment.

Distortion Product Otoacoustic Emission Test is Not the Test to Use in Nonclinical Safety Assessment

Ototoxicity and ocular toxicity screening are but two examples of specialty product lines that are often employed as Tier II or III nonclinical safety/hazard screening assessments. Compared to the regulatory guidelines that govern over standard toxicology or neurotoxicology programs, there is a paucity of regulatory strategies to address these specialized product lines. With respect to ototoxicity testing, we argue for the inclusion of the "least burdensome principles" adopted by the US FDA in providing the most pragmatic, efficient, and directed identification of potential harm to auditory function in the nonclinical safety arena. We argue for the exclusive use of the auditory brainstem response and the exclusion of the distortion product otoacoustic emissions (DPOAEs) in these Tiered II safety assessment programs. The inclusion of both are a burden on operational staff and, due to the extended episodes of anesthesia required to conduct both assays, this strategy poses a health and welfare concern for the selected animal species to be used. The DPOAE does not provide any sufficiently valid or reliable data above and beyond the gold standard ABR data, followed by complete oto-histopathology and cytocochleogram combination designs.

Measuring Distortion-Product Otoacoustic Emission With a Single Loudspeaker in the Ear: Stimulus Design and Signal Processing Techniques

The distortion-product otoacoustic emission (DPOAE) is a backward propagating wave generated inside the cochlea during the wave amplification process. The DPOAE signal can be detected rapidly under relatively noisy conditions. In recent years, the earphone industry demonstrated interest in adopting DPOAE as an add-on feature to make their product “intelligent” of inner-ear status. However, a technical challenge remains to be tackled—the loudspeaker in an earphone generates its own cubic distortion at the same frequency as DPOAE. Unfortunately, the intensity of loudspeaker distortion is typically comparable to that of the DPOAE, if not higher. In this research, we propose two strategies, namely compensation and cancellation, to enable DPOAE measurement with a single loudspeaker. The compensation strategy exploits the part of the growth function of the loudspeaker distortion which is almost linear, and thus suppresses the distortion it generates while retaining a larger portion of DPOAE in the residual signal. The cancellation strategy utilizes a one-dimensional Volterra filter to remove the cubic distortion from the loudspeaker. Testing on normal-hearing ears shows that the compensation strategy improved the DPOAE-to-interference ratio by approximately 7 dB, resulting in a cross-correlation of 0.62 between the residual DPOAE level and the true DPOAE level. Meanwhile, the cancellation strategy directly recovered both the magnitude and the phase of DPOAE, reducing the magnitude estimation error from 15.5 dB to 3.9 dB in the mean-square sense. These pilot results suggest that the cancellation strategy may be suitable for further testing with more subjects.

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.

Outcomes of newborn hearing screening at an academic secondary level hospital in Johannesburg, South Africa

BACKGROUND

The Health Professions Council of South Africa (HPCSA) issued early hearing detection and intervention guidelines, which has universal newborn hearing screening (UNHS) as one of the important goals. Despite established evidence of the importance of UNHS globally, there has been no mandated formalised and standardised implementation as yet in South Africa.

OBJECTIVES

The aim of this study was to describe the outcomes of newborn hearing screening (NHS) in an academic secondary level hospital in Johannesburg, South Africa.

METHODS

This was a prospective non-experimental feasibility study over a 3-month period, involving conducting hearing screening of 121 neonates. Audiologists conducted a risk factor assessment, otoscopic examinations and distortion product otoacoustic emissions (DPOAEs) screening on each neonate, with follow-up appointments for re-screening and diagnostic audiological assessments for all neonates with refer findings. Data were analysed using STATA intercooled version 11©, through both descriptive and inferential statistics (Fisher's exact test), with significance established where p-values less than 0.05 were considered statistically significant.

RESULTS

Of the 121 neonates screened, the majority (75%) were screened in the first 24 h of life. A high refer rate (47%) of the total sample was found on DPOAE screening. No maternal or neonatal risk factors were found to be significantly associated with refer findings.

CONCLUSION

Findings contribute towards the existing evidence base that raises implications for successful implementation of NHS programmes in public healthcare in South Africa. Screening protocols need to consider the timing of screening, the measures and procedures adopted in the screening protocols, as well as the follow-up strategies.

Sensitivity and Specificity of Pure-Tone and Subjective Hearing Screenings Using Spanish-Language Questions

Purpose The purpose of this study is to determine the sensitivities and specificities of different audiometric hearing screening criteria and single-item and multi-item hearing disability questionnaires among a group of Spanish-speaking adults in a rural community. Method Participants were 131 predominantly older (77% 65+ years) Hispanic/Latinx adults (98%). A structured Spanish-language interview and pure-tone threshold test data were analyzed for each participant. The sensitivities and specificities of three single questions and the Hearing Handicap Index for the Elderly-Screening (HHIE-S; Ventry & Weinstein, 1983) in Spanish, as well as three audiometric screening criteria, were evaluated in relation to the pure-tone threshold test for detecting hearing loss. Results Sensitivity and specificity of audiometric screening criteria varied, but the highest sensitivity was found for the criterion of > 25 dB HL at 1-4 kHz in either ear. The single self-perception question, "¿Cree usted que tiene pérdida de audición? (Do you think you have a hearing loss?)," was shown to be the most sensitive self-report screening compared to other single-item questions and the HHIE-S. This single question was as sensitive as an audiometric screening to detect a moderate hearing loss (> 40 dB HL in either ear). Results from the Spanish HHIE-S indicated poor performance to detect hearing loss in this population, consistent with previous research. Conclusions Among older Spanish-speaking adults, self-reported hearing status had varying sensitivities depending on the question asked. However, of the tools evaluated, the self-perception question proved to be a more sensitive and specific tool than a multi-item screen. Objective audiometric testing (> 25 dB HL) resulted in the highest sensitivity to detect a mild hearing loss.

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.

Prevalence and referral rates in neonatal hearing screening program using two step hearing screening protocol in Chennai - A prospective study

OBJECTIVE

To estimate the prevalence and referral rates in well born and high risk babies using two step hearing screening protocol with Distortion Product Otoacoustic Emissions (DPOAE) and Automated Auditory Brainstem Response (AABR).

METHOD

A prospective study was carried out on 1405 neonates (983 well born babies and 422 high risk babies) who were screened during May 2013 to January 2015 at Institute of Obstetrics and Gynecology, Madras Medical College, Chennai. All neonates were screened using two step screening protocol. They were initially tested with DPOAE. Referred babies in DPOAE were screened with AABR subsequently.

RESULTS

Among 1405 (100%) neonates 983 (69.96%) were well born babies and 422 (30.03%) were high risk babies. Total referral rate in DPOAE was found to be 311 (22.13%) among which 195 (13.87%) were well born babies and 116 (8.25%) were high risk babies. Out of 311 babies 31 (2.20%) babies were referred in AABR screening. In 31 babies referred in AABR 11(0.78%) were from well born group and 20 (1.42%) were from the high risk group. Further diagnostic evaluation of these babies, 2 (0.14%) were confirmed to have hearing loss. This study reveals, the prevalence of congenital hearing loss in our population is 1.42 per 1000 babies.

CONCLUSION

Using two step protocol especially AABR along with DPOAE at the initial level of testing significantly reduces referral rates in new born screening programs. Also AABR decreases the false positive responses hence increasing the efficiency of screening program.

Revisiting Oto-Acoustic Emissions

Oto-acoustic emissions (OAEs) are an audiometric diagnostic test that allows quick objective measure of hair cell function in the inner ear. It is a reflection of hearing function at the interface of conductive and sensorineural components in the human ear. Unfortunately, it is not commonly used due to the unique expertise and niche equipment required to successfully carry it out. This article is to further shed light about the use of such tests to junior doctors so that such resources can be better utilised. It also reviews the current and possible future applications of OAEs at the frontiers in otology today.

Effects of changes in click-evoked otoacoustic emission (CEOAE) pass criteria, as used in the English newborn hearing screening program, on screening outcome

OBJECTIVE

There were two objectives, firstly what effect does a change in the pass criteria of a click-evoked otoacoustic emission (CEOAE) newborn hearing screen have on the number of cases of significant hearing impairment detected by follow up diagnostics, and secondly how does this change affect the screen pass rate?

DESIGN

Changes in the pass criteria were: reduction in the signal-to-noise ratio (SNR); reduction in the minimum signal level (MSL); inclusion of the 1-kHz half-octave band; reduction from two to a single half-octave band.

STUDY SAMPLE

Data from three screening sites was used within the English newborn hearing screening program from the period 2002 to 2006, with a total number of births of about 40,000. There were 42 bilateral and 43 unilateral cases of significant hearing impairment.

RESULTS

No effect on the number of cases detected by follow up diagnostics was observed when: (1) SNR was reduced to a minimum of 5 dB; (2) MSL was reduced to -10 dB SPL; and (3) the 1-kHz band was included. With all these changes the percentage pass rate improved by 0.36%.

CONCLUSIONS

The current choice of SNR and MSL criteria appears robust. Only a small increase in pass rate is possible without affecting case detection.

Arteriovenous fistula presenting as a failed hearing test

Congenital arteriovenous fistulas (AVFs) result from inadequate differentiation of the vascular system during fetal development. This case report describes an AVF of the neck, which possibly manifested as noise interference during a newborn hearing-screening test by otoacoustic emissions (OAEs). This report is in compliance with the institutional review board regulations of the University of Puerto Rico School of Medicine.

Newborn hearing screening and strategy for early detection of hearing loss in infants

OBJECTIVE

More than 80% of permanent hearing losses (HL) in children are congenital. Newborn hearing screening (NHS) is the best method for early detection of suspected hearing loss. If the NHS is not universal more than 30% permanent hearing losses are not identified. There are various methods of NHS: otoacoustic emissions (TEOAE, DPOAE) and automatic auditory brainstem response (AABR). After hearing screening, and when hearing loss is suspected, tympanometry and audiological methods then used for determination of hearing threshold; these include ABR, ASSR or/and behavioral methods. The goal of this study is to evaluate the influence of UNHS on the early detection of hearing loss in children before and after the implementation of obligatory universal newborn hearing screening in Slovakia, and also on the etiologic evaluation of hearing impaired infants identified by screening.

METHOD

In Slovakia NHS started in 1998 and was provided in ENT departments. From May 1, 2006 UNHS has been mandatory in Slovakia, using two stages TEOAE in all newborn departments in Slovakia (64 newborn departments). In year 2005--42% of newborns in Slovakia were screened, in 2006--66% newborns and in 2007--94, 99% (three small newborn departments do not yet have equipment for OAE screening). For determination of hearing thresholds ASSR are used in two ENT departments and ABR in the other four ENT departments.

RESULTS

Comparing the number of identified cases with bilateral severe permanent HL or deafness before and after UNHS, 22.8% more cases of PHL were identified in the first year of UNHS. Also the average age of diagnosis of PHL was lower. In the year 2007, 94% of newborns were screened. We found 0.947/1000 newborns with bilateral severe PHL (35.9%) more than before UNHS). After audiologic and etiologic assessment of the 76 infants who failed screening, 5 (6.58%) were found to have normal hearing, 16 (22.54%) had unilateral and 55 (77.46%) had bilateral SNHL. A non-syndromic genetic cause was present in 25.45% of cases, syndromic in 9%, perinatal cause (31%), congenital CMV infection in 7.27%, bilateral cochlear anomalies without other abnormality in 1.83% and unknown etiology in 25.45%.

Hearing screening and diagnostic evaluation of children with unilateral and mild bilateral hearing loss

More than 90% of newborns in the United States are now being screened for hearing loss. A large fraction of cases of unilateral hearing loss and mild bilateral hearing loss are not currently identified through newborn hearing screening. This is of concern because a preponderance of research has demonstrated that unilateral hearing loss and mild bilateral hearing loss can lead to developmental delays and educational problems for some children. To help address this probable underidentification of unilateral hearing loss and mild bilateral hearing loss among infants and children, the Centers for Disease Control and Prevention Early Hearing Detection and Intervention program and the Marion Downs Hearing Center convened a workshop in Breckenridge, Colorado, in July 2005. During this workshop, several issues related to screening and diagnosing unilateral hearing loss and mild bilateral hearing loss were identified, as well as recommendations for future research in this area. Issues identified included the lack of standardized definitions for permanent unilateral hearing loss and mild bilateral hearing loss; the use of screening protocols that are primarily designed to identify bilateral and unilateral hearing losses of a moderate degree or greater (eg, above 40 dB); calibration of screening equipment; availability of facilities that can provide the full range of audiologic, diagnostic, and management services to this pediatric population; and an overall lack of awareness by many professionals and families about the potential effect of unilateral hearing loss and mild bilateral hearing loss. Suggestions for future research, such as identifying ways to improve the identification of cases of unilateral hearing loss and mild bilateral hearing loss, were also discussed.

Hearing screening and middle ear measures in American Indian infants and toddlers

American Indian children have three times the rate of otitis media compared to the general population, yet prospective cohort studies of OME and hearing loss have not been previously reported in American Indian infants. Between 1997 and 2003, a cohort of 421 infants was enrolled at birth from Minnesota American Indian reservations and an urban clinic and followed to age 2 years. This study reports OAE hearing screening results related to OME diagnoses, as well as risk for recurrent hearing screening failure and OME in American Indian infants and children.

METHODS

Infants were prospectively assessed at regular intervals with pneumatic otoscopy, distortion product otoacoustic emissions, and tympanometry by nurses who were trained in all procedures and validated on pneumatic otoscopy.

RESULTS

In the newborn period, 23.5% of infants failed hearing screening in at least one ear. Hearing screening failures increased to 29.9% from 2 to 5 months of age. Technical fail results due to excessive noise occurred frequently in infants 6-24 months of age, making interpretation of true pass and fail rates questionable in older infants. OAE test result was associated with OM diagnosis, and this relationship strengthened with age, with the strongest association above 6 months of age.

CONCLUSIONS

A high rate of hearing screening failures occurred among American Indian infants in the first 5 months of age, and was significantly associated with a correspondingly high rate of otitis media. Only one infant out of 366 was identified with sensorineural hearing loss, thus essentially all of the hearing screening failures reflected either a middle ear origin or other temporary problems. OAE screening provided a valuable hearing screening measure in this population at high risk for recurrent otitis media, but due to excessive noise in infants 6 months and older, practical use of OAE screening is limited. Use of behavioral assessment is needed after 6 months of age, when high rates of OME persist in this population. Increased efforts to develop public and medical education, as well as screening, diagnosis and treatment programs are needed to detect and decrease recurrent OME in American Indian infants and children.

Diagnostics of the Cochlear Amplifier by Means of Distortion Product Otoacoustic Emissions

Distortion product otoacoustic emission (DPOAE) growth functions reflect the active nonlinear cochlear sound processing when using a primary-tone setting which accounts for the different compressions of the two primaries at the DPOAE generation site and hence provide a measure for objectively assessing cochlear sensitivity and compression. DPOAE thresholds can be derived from extrapolated DPOAE input/output (I/O) functions independently of the noise floor and consequently can serve as a unique measure for reading DPOAE measurements. The thus-estimated DPOAE thresholds exhibit a close correspondence to behavior audiometric thresholds and thus can be used for reconstructing an audiogram, i.e., a DPOAE audiogram. The DPOAE I/O functions' slope increases with cochlear hearing loss and thus provides a measure for assessing recruitment. Hence, DPOAE I/O functions can give more information for diagnostic purposes than those of DP grams, transiently evoked OAEs (TEOAEs), or auditory brain stem responses (ABRs). DPOAE audiograms can be applied in pediatric audiology to assess cochlear dysfunction in a couple of minutes. In newborn hearing screening, they are able to detect transitory sound-conductive hearing loss and thus can help to reduce the rate of false-positive TEOAE responses in the early postnatal period. Since DPOAE I/O functions are correlated with loudness functions, DPOAEs offer the possibility of basic hearing aid adjustments, especially in infants and children. Extrapolated DPOAE I/O functions provide a tool for a fast automated frequency-specific and quantitative evaluation of hearing loss.

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

OBJECTIVE

Suitability in clinical practise of three currently available devices designed for automated newborn hearing screening, one combining evoked otoacoustic emissions (EOAE) and automated auditory brain stem response (AABR), the Echoscreen-TDA from Fischer-Zoth, and two AABR screeners, the Algo 3 from Natus and the Beraphone MB11 from Maico, were tested prospectively.

METHODS

Transiently evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) were measured in one ear of 150 healthy newborns using the Echoscreen-TDA. Three groups of 50 subjects each were tested additionally for AABR recordings either with Echoscreen-TDA, Algo 3 or Beraphone MB11. Measurements were performed after the second day of life. The following aspects were evaluated: (a) subject-instrumentation interface (b) test time (c) costs (unit price and costs for disposable material) and (d) pass rates.

RESULTS

Connecting the subjects to the device was the easiest for EOAE measurements with the Echoscreen-TDA, followed by AABR recordings with the Algo 3 and Echoscreen-TDA and were most difficult with the Beraphone MB11. The median test time on one ear was less than 30 s for EOAE measurements and 4-5 min for AABR recordings. Costs for the equipment and for disposable material were lowest for the Echoscreen-TDA and Beraphone MB11, respectively and highest for the Algo 3. Pass rates were highest with 98% for AABR recordings using the Algo 3 and lowest with 92% for AABR recordings using the Beraphone MB11, but differences were not statistically significant.

CONCLUSIONS

All tested devices can be used for universal neonatal hearing screening. It was easier to connect the subject to the device and measurements were quicker for OAE than for AABR measurements. Echoscreen-TDA combines the two techniques and had the lowest costs for the AABR equipment. Algo 3 had the highest costs for the equipment and for disposable material, but it was highly reliable, and both ears can be tested simultaneously. Connecting the subject was the most difficult with the Beraphone MB11, but there were no disposable supply costs.

Newborn hearing screening: costs of establishing a program

OBJECTIVE

To evaluate the costs and performance characteristics associated with the start-up phase of Universal Newborn Hearing Screening Programs, one utilizing automated auditory brainstem response (AABR) and the other using transient evoked otoacoustic emissions (TEOAE).

STUDY DESIGN

Economic and performance data were collected at the initiation of both screening programs. Data were collected until 1500 newborn infants were screened or until a referral rate for further audiologic evaluation at hospital discharge of less than or equal to 5% was achieved. Data collected included screening pass/fail rates, referral rates and personnel, equipment, and supply utilization. Actual costs of personnel, equipment, and supplies were used. Statistical comparisons of proportions using z-statistic with the one-tailed test and an alpha of 0.01 were made.

RESULTS

Screening in the AABR program was performed by neonatal nurses, whereas screening in the TEOAE program was performed by master's level audiologists. The average age at initial screen was 29 hours for TEOAE, and 9.5 hours for AABR. Eighty-four percent of infants was screened within 24 hours in the AABR program, in contrast to 35% in the TEOAE program. Throughout the duration of the study, the referral rate at hospital discharge remained approximately 15% for the TEOAE program. The AABR referral rate began at 8% and was less than 4% at the completion of the study. Pre-discharge total costs for initiating and establishing the programs were US$49,316 for TEOAE and US$47,553 for AABR. Cost per infant screened was US$32.23 and US$33.68, respectively. When post-discharge screening and diagnostic evaluation costs were included, the total cost per infant screened was US$58.07 for TEOAE and US$45.85 for AABR.

CONCLUSION

AABR appears to be the preferred method for universal newborn hearing screening. AABR was associated with the lowest costs, achieved the lowest referral rates at hospital discharge, and had the quickest learning curve to achieve those rates.