Newborn Hearing Screening Benefits Children, but Global Disparities Persist

The digit triplet test for school-age hearing screening: comparing languages, school grades and scoring methods in a large sample

OBJECTIVE

To investigate the reliability of a bilingual school-age hearing screening in four school grades based on the Digit Triplet Test (DTT) in two languages and to investigate three calculation methods for referral values in their ability to detect hearing losses and avoid false-positive results.

DESIGN AND STUDY SAMPLE

3255 children, aged between 10 and 17 years old, were tested during a systematic hearing screening program in a bilingual, French-German area in Belgium. French speaking children were tested with a French DTT, German children were tested with a German DTT. The SRT-values, their stability and measurement error were investigated per grade and language. The number of false-positive results was studied for three referral methods, using additional audiometric data of 71 children.

RESULTS

Our data showed that reliable results with high stability and a small measurement error can be obtained in only around two minutes per ear. Differences between languages are minimal and grade-specific referral values were necessary. A referral method considering the lowest SNRs in the adaptive staircase reduces the number of false-positive results substantially.

CONCLUSION

The DTT versions of different languages can be used reliably in a bilingual school-age hearing screening program when grade-specific, alternative referral methods are implemented.

Making a Difference from Day One: The Urgent Need for Universal Neonatal Hearing Screening

Neonatal hearing screening (NHS) is a critical public health measure for early identification of hearing loss, ensuring timely access to interventions that can dramatically improve a child's language development, cognitive abilities, and social inclusion. Beyond clinical benefits, NHS provides long-term advantages in education and quality of life. Given that congenital hearing loss affects approximately 1-2 in every 1000 newborns worldwide, the case for universal screening is clear. Countries like the United States and Australia have successfully implemented NHS, leading to earlier diagnoses, improved language development, and better educational outcomes. In Europe, while many nations have adopted NHS, consistency remains a challenge. Countries such as Norway and the United Kingdom stand out for their well-established systems, whereas others, like Greece, have made notable progress but have yet to mandate NHS nationwide. This highlights the need for cohesive national policies across Europe to ensure universal coverage. Screening methods such as Transient Evoked Otoacoustic Emissions (TEOAE) and Automated Auditory Brainstem Response (AABR) are established tools for detecting hearing impairments in neonates. Despite their demonstrated efficacy, NHS remains inconsistent globally, particularly in low- and middle-income regions that lack mandatory policies or access to reliable screening technologies. This perspective advocates for the urgent need to make NHS mandatory in all countries, emphasizing its societal benefits and cost-effectiveness. Early diagnosis supports prompt intervention, like hearing aids or cochlear implants, which are most effective when implemented before six months. It also empowers families to make informed decisions, fosters educational inclusion, and mitigates the social and emotional challenges of undiagnosed hearing loss. Policymakers, healthcare providers, and international organizations must prioritize universal NHS to ensure no child is left behind due to unaddressed hearing loss.

Early Hearing Detection and Intervention programmes for neonates, infants and children in non-Asian low-income and middle-income countries: a systematic review

INTRODUCTION

Early Hearing Detection and Intervention (EHDI) programmes were established to reduce the impact of hearing loss on children. High-income countries (HICs) have resources and knowledge to execute these programmes. However, financial and other resource constraints limit the availability of these programmes to low-income and middle-income countries (LMICs). Yet, LMICs have explored strategies to implement EHDI programmes in their context; the outcomes are still largely unknown.The aim of this study is to identify the various models of the EHDI program implemented in non-Asian LMICs.

AIM

METHOD: Studies published between 2010 and 2023 reporting EHDI programmes in non-Asian LMICs for children were considered. The primary databases searched were PubMed, Scopus, Web of Science, EBSCOHost, EBSCO-CINAHL and ProQuest dissertations. The search results are summarised using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses chart. Quality appraisal and risk-of-bias assessment were assessed. Using the retrieved data, a narrative synthesis of the identified methods and forest plots for the prevalence estimate was created.

RESULTS

Fifty-six studies from 16 LMICs were included. They were grouped into 29 hearing screening programmes for neonates and infants and 26 programmes for older children. Predominantly hospital-based screening was employed for neonates and infants and school-based screening for older children. Two-stage otoacoustic emissions screening was employed for neonates and infants, while single-stage pure tone audiometry with otoscopy screening was used for older children. Predominantly, audiologists performed screening and diagnostics for neonates/infants while community health workers performed screening for the older children. Screening aspects were reported predominantly and not diagnostic evaluation/intervention outcomes. Overall, the economics of EHDI was reported only anecdotally in a few studies.

CONCLUSION

The screening strategies were not uniform among non-Asian LMICs. The protocols used were similar to HICs, yet few developed protocols adapting the Joint Committee of Infant Hearing. However, long-term outcomes such as rate of identification, suitable intervention and their outcomes are not known. EHDI programmes with successful outcomes of early intervention must be studied and reported with economic evaluations.

Community-based infant hearing screening: Outcomes of a rural pilot programme

BACKGROUND

 Community-based universal newborn hearing screening (UNHS) has not been fully realised in South Africa despite the availability of contextually relevant early hearing detection and intervention guidelines. Research has confirmed the feasibility of implementing UNHS programmes in urban contexts; however, limited information exists for rural contexts.

OBJECTIVES

 The aim of the study was to describe the outcomes in terms of coverage rate, referral rate and follow-up rate of a 1-year UNHS pilot programme implemented at three primary health care (PHC) clinics in the Limpopo province.

METHOD

 A descriptive retrospective review of 2 302 audiological records of infants who underwent NHS between July 2014 to June 2015 was conducted.

RESULTS

 The mean age at first-stage screen was 112 days (16 weeks). The coverage rate was 87% for the infants screened at 3- and 10- days clinic visits and 27% for infants screened at the 6-week immunisation visit. The first-stage referral rate was 33.9% and 8.3% for the overall second stage referral for diagnostic audiology services. The follow-up rate for rescreens at the clinical level was 77%, while for initial diagnostic assessments, it was 26%.

CONCLUSION

 Although not all benchmarks were met within the first year of implementation, the high coverage- and low referral rates, especially in the last 6 months, are the first steps in improving the outcomes of the screening programme.Contribution: The findings confirm the feasibility of implementing community-based UNHS programmes in rural areas in South Africa. Regular monitoring and evaluation contribute to the success of screening programmes.

The Otoacoustic Emissions in the Universal Neonatal Hearing Screening: An Update on the European Data (2004 to 2024)

Background: The reported data on European universal neonatal hearing screening (UNHS) practices tend to be scarce, despite the fact that the European Union project, EUScreen, collected unofficial data from 38 collaborating European institutions. The objectives of this systematic review were as follows: (a) to identify the most recent (in a 20-year span) literature information about UNHS programs in Europe and (b) to provide data on the procedures used to assess the population, the intervention policies, and on the estimated prevalence of congenital hearing loss with emphasis on the bilateral hearing loss cases. Methods: Queries were conducted via the Pubmed, Scopus and Google Scholar databases for the time period of 2004-2024. The Mesh terms used were "OAE", "Universal Neonatal Hearing Screening", "congenital hearing loss" and "well babies". Only research articles and review papers of European origin were considered good candidates. The standard English language filter was not used, in order to identify information from non-English-speaking scientific communities and groups. Results: Very few data and reports were identified in the literature search. Eleven manuscripts were identified corresponding to eight UNHS programs. Except in Poland, most of the data refer to regional and not national programs. The screening coverage estimates of all programs exceed 90%; infants were mostly assessed by a three-stage protocol (TEOAE + TEOAE + AABR), followed by a clinical ABR test. The average prevalence (i.e., from well babies AND NICU infants) of bilateral hearing loss ranged from 0.5 to 20.94 per 1000 (Zurich sample). Infants presenting unilateral or bilateral hearing losses were first rehabilitated by hearing aids and consequently (>15 mo) by cochlear implants. Conclusions: Even though UNHS programs are well-established clinical practices in the European States, the amount of information in the literature about these programs is surprising low. The existing data in the timespan 2004-2024 corroborate the international UNHS data in terms of coverage and bilateral hearing loss prevalence, but there is a strong need to supplement the existing information with the latest developments, especially in the area of hearing loss rehabilitation.

Neonatal Markers of Prematurity as Predictors of Permanent Childhood Hearing Loss and Neurodevelopmental Impairment in Children Admitted to the Neonatal Intensive Care Unit

Need for admission to the neonatal intensive care unit (NICU) confers an increased risk of hearing loss in the newborn and of later neurodevelopmental impairment. In this retrospective longitudinal case-controlled study, we assess how the degree of prematurity, measured via gestational age, birth weight, and z-scores, in 138 infants admitted to the NICU are associated with permanent childhood hearing loss (PCHI) and 2-year developmental outcomes. Logistic regression analyses, Kruskal-Wallis analysis of variance, and Chi-squared tests were used. Independent of prematurity, PCHI and NICU admission were predictive of poor developmental outcomes. Twenty-one (47%) children with PCHI had a moderate-to-severe developmental delay, compared to three (7%) matched controls. Days in the NICU but not z-scores predicted PCHI. Z-score was not prognostic of moderate or severe developmental impairment in children with PCHI. The odds ratio of moderate-to-severe neurodevelopmental impairment with PCHI was high, at 12.48 [95% CI = 3.37-46.40]. Children with PCHI were significantly more likely to have cerebral palsy than their matched counterparts (30% vs. 2%). These findings challenge the conventional focus on gestational age and birth weight on neurodevelopmental outcomes for children with PCHI and NICU admission. A more nuanced approach to monitoring and intervention is needed.

Coalition for Global Hearing Health Hearing Care Pathways Working Group: Guidelines for Clinical Guidance for Readiness and Development of Evidence-Based Early Hearing Detection and Intervention Programs

Editor's Note: The following article discusses the timely topic Clinical Guidance in the areas of Evidence-Based Early Hearing Detection and Intervention Programs. This article aims to discuss areas of services needed, guidance to countries/organizations attempting to initiate early hearing detection and intervention systems. Expert consensus and systematic/scoping reviews were combined to produce recommendations for evidence-based clinical practice. In Ear and Hearing, our long-term goal for the Point of View article is to stimulate the field's interest in and to enhance the appreciation of the author's area of expertise. Hearing is an important sense for children to develop cognitive, speech, language, and psychosocial skills. The goal of universal newborn hearing screening is to enable the detection of hearing loss in infants so that timely health and educational/therapeutic intervention can be provided as early as possible to improve outcomes. While many countries have implemented universal newborn hearing screening programs, many others are yet to start. As hearing screening is only the first step to identify children with hearing loss, many follow-up services are needed to help them thrive. However, not all of these services are universally available, even in high-income countries. The purposes of this article are (1) to discuss the areas of services needed in an integrated care system to support children with hearing loss and their families; (2) to provide guidance to countries/organizations attempting to initiate early hearing detection and intervention systems with the goal of meeting measurable benchmarks to assure quality; and (3) to help established programs expand and improve their services to support children with hearing loss to develop their full potential. Multiple databases were interrogated including PubMed, Medline (OVIDSP), Cochrane library, Google Scholar, Web of Science and One Search, ERIC, PsychInfo. Expert consensus and systematic/scoping reviews were combined to produce recommendations for evidence-based clinical practice. Eight essential areas were identified to be central to the integrated care: (1) hearing screening, (2) audiologic diagnosis and management, (3) amplification, (4) medical evaluation and management, (5) early intervention services, (6) family-to-family support, (7) D/deaf/hard of hearing leadership, and (8) data management. Checklists are provided to support the assessment of a country/organization's readiness and development in each area as well as to suggest alternative strategies for situations with limited resources. A three-tiered system (i.e., Basic, Intermediate, and Advanced) is proposed to help countries/organizations at all resource levels assess their readiness to provide the needed services and to improve their integrated care system. Future directions and policy implications are also discussed.

Gestational diabetes mellitus and the hearing of newborns:A nested case-control study in tropical province of China

OBJECTIVE

This study aims to determine the association of gestational diabetes mellitus (GDM) and the results of newborn hearing screening(NHS).

METHODS

A nested case-control study was conducted in a cohort of newborns who were born between June 2021 to December 2021 and underwent neonatal hearing screening.GDM was diagnosed according to the 75 g 2 h oral glucose tolerance test (OGTT) at 24-28 gestational weeks.A total of 369 pregnant women at the same hospital were individually matched in a 1:2 ratio by maternal age (±2 years), gestational age (±3 days) and sex of newborn.Chi-square test was utilized to evaluate associations between GDM and the results of NHS.

RESULTS

Abnormal NHS results in the GDM group was more frequent than non-GDM group.When comparing the two groups (GDM case and contol), we found significant differences (p < 0.05) between them.Whereas the difference was not statistically significant (p > 0.05) by delivery modes in both case and control groups.

CONCLUSION

Maternal history of GDM could lead to significantly higher failling rate of NHS.

A systematic review of the prevalence of late identified hearing loss in childhood

OBJECTIVES

The objective of this systematic review was to assess the evidence about the prevalence of permanent hearing loss for children not identified from newborn hearing screening (NHS).

DESIGN

Articles were grouped into three categories based on the methodological approach: (1) all participants received diagnostic testing, (2) otoacoustic emission (OAE) or pure tone screening was completed and those not passing were referred for a diagnostic test, and (3) data were retrieved from archival records. Study characteristics, prevalence, and contextual factors were synthesised and narratively described.

STUDY SAMPLE

30 peer-reviewed articles.

RESULTS

Prevalence of permanent hearing loss per 1,000 children ranged from 0.32 to 77.87 (M = 7.30; SD = 16.87). Variations in the criteria for inclusion contributed to prevalence differences. Prevalence was higher when unilateral and milder degrees of hearing loss were included, and older children had higher prevalence (M = 13.71; SD = 23.21) than younger children (M = 1.57; SD = 0.86).

CONCLUSION

There is scant research on prevalence of childhood hearing loss after NHS that utilised methods to accurately differentiate between permanent and temporary hearing loss. Rigorous research is needed on the prevalence of permanent childhood hearing loss to inform strategies for monitoring, identification, intervention, and management.

Newborn hearing screening in Eastern Saudi Arabia: A tertiary hospital experience

OBJECTIVES

To analyze the performance of a leading institution in implementing newborn hearing screening and address two key areas: the knowledge gap in screening practice and the prevalence of permanent sensorineural hearing loss in Saudi Arabia.

METHODS

We analyzed the prevalence of hearing impairment in all live births at King Fahad Hospital of the University, Al Khobar, Saudi Arabia, from September 2018 to June 2022. Automated auditory brainstem response was used for both initial screening and rescreening. Newborns who failed the rescreening underwent a diagnostic evaluation. We assessed the coverage of initial screening, the rate of lost follow-up, referrals for rescreening and diagnostic evaluation, and the prevalence of hearing impairment.

RESULTS

A total of 5,986 newborns were born. Of these, 96.5% were screened. The passing rate for the initial screening and rescreening was 71.8%. However, 27.5% of newborns were lost to follow-up. Only 0.7% required referral for a diagnostic evaluation. The overall prevalence of hearing impairment was 2.6 per 1,000 newborns.

CONCLUSION

Early identification of hearing loss through newborn screening improves the lives of affected individuals. Our program currently meets the World Health Organization's 1-3-6 benchmark goals. However, the underestimation of permanent hearing loss due to the 30% lost-to-follow-up rate is a limitation. Emphasizing the importance of the screening program is crucial to raising awareness and improving the accuracy of prevalence rates.

UK and US risk factors for hearing loss in neonatal intensive care unit infants

IMPORTANCE

Early detection and intervention of hearing loss may mitigate negative effects on children's development. Children who were admitted to the neonatal intensive care unit (NICU) as babies are particularly susceptible to hearing loss and risk factors are vital for surveillance.

DESIGN, SETTING AND PARTICIPANTS

This single-centre retrospective cohort study included data from 142 inborn infants who had been admitted to the NICU in a tertiary regional referral centre. Data were recorded for 71 infants with confirmed permanent congenital hearing loss hearing loss. To determine impact of NICU admission independently of prematurity, babies were individually matched with 71 inborn infants on gestational age, birthweight, and sex.

MAIN OUTCOMES AND MEASURES

Neonatal indicators were recorded for all children with permanent congenital hearing loss. Presence of UK and US risk factors for hearing loss were collected on the neonatal population with hearing loss and for the matched controls.

RESULTS

A fifth (21%) of babies with hearing loss had one or more UK risk factors whereas most (86%) had at least one US risk factor. False positives would be evident if US factors were used whereas the matched controls had no UK risk factors. Ten babies who at birth had no UK or US risk factors did not have any significant neonatal indicators identified in their records, one was ventilated for one day and two had a genetic anomaly.

CONCLUSIONS AND RELEVANCE

Current risk factors for hearing loss we identified for follow-up in this high-risk group are highly specific for congenital hearing loss. UK risk factors were highly specific for hearing loss but not sensitive and conversely, US risk factors are sensitive but not specific so false positives would be recorded. A national study of neonatal indicators could provide the utility to test which combinations of risk factors provide high sensitivity without losing specificity.

An insight into Indonesia's progress for newborn screening program: What is currently going on

Objectives

In this literature review, we describe the progress of Indonesia's NBS program (which is heavily centered on CH screening), its current pilot projects, and what lies ahead for this program.

Setting

Since its conception began with congenital hypothyroidism (CH) screening, Indonesia has experienced plodding progress in NBS. There is a shortage of literature discussing the history, or the lack of, and journey of NBS in Indonesia.

Methods

We searched for literature in Pubmed and Google Scholar with keywords such as "Newborn Screening, "Neonatal Screening," "Indonesia," "Asia Pacific," "Congenital Hypothyroidism," "Congenital Adrenal Hyperplasia,""Critical Congenital Heart Disease," "Hearing Loss," and "Inborn Error of Metabolism."

Results

The only mandatory and regulated NBS program in Indonesia is congenital hypothyroid (CH) screening, with some pilot projects being conducted on screening for congenital adrenal hyperplasia (CAH), critical congenital heart disease (CCHD), hearing loss, and to a lesser extent, inborn error of metabolisms (IEMs).

Conclusion

Despite the evidence and benefits, the government does not mandate or regulate newborn diseases such as CHD, CAH, hearing loss, and IEMs. The lack of regulation exists despite multiple pilot projects and studies showing a benefit in at least trying to screen newborns for those conditions.

Evaluation of newborn hearing screening program in Jordan

Introduction

The Newborn Hearing Screening (NHS) program was officially launched in Jordan in 2021. Since its inception, no studies have examined the effectiveness of the program. This study seeks to assess the effectiveness and outcomes of the NHS program in Jordan.

Methods

A retrospective cross-sectional study was conducted to investigate the program coverage rate, referral rate, loss to follow-up rate and the hearing status of newborns who successfully completed the necessary diagnostic assessment. Live births in all hospitals administered by the Ministry of Health (MoH) in Jordan from July 2021 to November 2023 were included.

Results

Out of 25,825 newborns delivered, 99.4% (25,682) were screened. A referral rate of 0.7% (189) was recorded. Approximately 61.9% of those referred (n = 117) had normal hearing, while 31.7% (60 infants) were diagnosed with hearing loss. The prevalence of congenital hearing loss was 0.14%, and the mean age for identifying hearing loss was 11 months.

Discussion

The current status of the NHS program in Jordan is promising. The program has achieved most benchmarks recommended by the Joint Committee on Infant Hearing (JCIH), demonstrating encouraging outcomes. There is a need to investigate and address the factors causing delays in the identification of hearing loss in Jordan.

Current Status of Newborn Bloodspot Screening Worldwide 2024: A Comprehensive Review of Recent Activities (2020-2023)

Newborn bloodspot screening (NBS) began in the early 1960s based on the work of Dr. Robert "Bob" Guthrie in Buffalo, NY, USA. His development of a screening test for phenylketonuria on blood absorbed onto a special filter paper and transported to a remote testing laboratory began it all. Expansion of NBS to large numbers of asymptomatic congenital conditions flourishes in many settings while it has not yet been realized in others. The need for NBS as an efficient and effective public health prevention strategy that contributes to lowered morbidity and mortality wherever it is sustained is well known in the medical field but not necessarily by political policy makers. Acknowledging the value of national NBS reports published in 2007, the authors collaborated to create a worldwide NBS update in 2015. In a continuing attempt to review the progress of NBS globally, and to move towards a more harmonized and equitable screening system, we have updated our 2015 report with information available at the beginning of 2024. Reports on sub-Saharan Africa and the Caribbean, missing in 2015, have been included. Tables popular in the previous report have been updated with an eye towards harmonized comparisons. To emphasize areas needing attention globally, we have used regional tables containing similar listings of conditions screened, numbers of screening laboratories, and time at which specimen collection is recommended. Discussions are limited to bloodspot screening.

Effects of Natural Delivery and Cesarean Section on the Result of First Hearing Screening of Newborns

BACKGROUND

Early detection and intervention of hearing issues in newborns are crucial for their auditory and speech development, necessitating newborn hearing screenings. This study aimed to investigate the impact of delivery methods, specifically natural delivery and cesarean section, on newborn hearing screening outcomes.

METHODS AND MATERIAL

A retrospective analysis was conducted on data from 600 newborns delivered at The First Affiliated Hospital of Shaoyang University between January 2020 and January 2023. The initial hearing screenings used the AccuScreen otoacoustic emission instrument. The study examined the influence of delivery method on the pass rates of newborns' first hearing screenings within and beyond 48 h postbirth.

RESULTS

The pass rates for the initial hearing screenings, conducted within and after 48 h of birth, were significantly higher in the natural delivery group compared to the cesarean section group (P < 0.05). Furthermore, multivariate analysis identified the delivery method as a significant factor influencing the pass rates of newborns' first hearing screenings.

CONCLUSIONS

The mode of delivery appears to affect the results of the initial hearing screenings of newborns, though further research is needed to validate these findings.

A language-independent hearing screening self-test at school-entry

The usage of a tablet-based language-independent self-test involving the recognition of ecological sounds in background noise, the Sound Ear Check, was investigated. The results of 692 children, aged between 5 and 9 years and 4 months, recruited in seven different countries, were used to analyze the validity and the cultural independence of test. Three different test procedures, namely a monaural adaptive procedure, a procedure presenting the sounds dichotically in diotic noise, and a procedure presenting all the sounds with a fixed signal-to-noise ratio and a stopping rule were studied. Results showed high sensitivity and specificity of all three procedures to detect conductive, sensorineural and mixed hearing loss > 30 dB HL. Additionally, the data collected from different countries were consistent, and there were no clinically relevant differences observed between countries. Therefore, the Sound Ear Check can offer an international hearing screening test for young children at school entry, solving the current lack of hearing screening services on a global scale.

Neonatal Hearing Screening: Challenges of COVID-19 Pandemic

This is a retrospective chart review of newborns referred to audiology between June and December 2020. Newborns who failed or did not have an initial newborn hearing screening (NBHS) at an academic, tertiary care medical center, either in the nursery or in the neonatal intensive care unit (NICU) prior to discharge, were referred for a follow-up audiology appointment. Forty-three patients were included who failed or did not receive an NBHS. Of 43 patients, 15 (34.9%) did not receive an initial hearing test due to coronavirus disease 2019 (COVID-19 protocols). Of the 15, 7 (16.3% of total 43) newborns had mothers who refused COVID-19 screening, and 5/7 were lost to follow-up (11.6% of total). Another 7/15 newborns (16.3% of total) had a COVID-19-positive mother, and 1 of these 7 was lost to follow-up (2.3% of total). One of the 15 newborns (2.3% of total) had a pending maternal COVID-19 test result at discharge, and this patient was also lost to follow-up.

Newborn Hearing Screening and Beyond: A Continuing Journey in the Philippines

This keynote lecture is a product of many years of hard work but today this is delivered in honor of Professor and Founding President of ORLIAC, Professor Emeritus Jan Veldman. Thank you for the opportunity to host ORLIAC in Manila way back in March 2018. For those who attended this, I gave a special lecture during the celebration of World Hearing Day on March 3, 2018, when ORLIAC was held in Manila and this gives an update on how we managed in the past four and a half years, with a COVID-19 pandemic in the past two and half years. The Philippines is an archipelago of more than 7,100 islands during high tide and up to 7,600 when it is low tide. It is situated in the Southeast Asian region. It is one of the countries with the highest population density, with a total population of 110 million spread over 300,000 square kilometers. The crude birthrate is at 19.9 per 1000 – in stark contrast with surrounding Southeast Asian nations now with a decreasing population such as Thailand, Vietnam, and Malaysia among others There have been three World Health Assembly (WHA) resolutions that emphasized the prevention of deafness and hearing loss. WHA 38.19 in 1985 then ten years later WHA 48.9 in 1995 and the last WHA 70.13 in 2017. These resolutions from the World Health Assembly emphasized that prevention of deafness and hearing loss should be incorporated in primary health care. As a result of the 2017 WHA 70.13 resolution, a World Hearing Report1was formulated and released last year in 2021 (Figure 1). The WHO Call to Action in 2000 recommended that Universal Newborn Hearing Screening (NHS) be implemented in all countries where rehabilitation services are established.2 In 1998, we did the first cochlear implantation in my country3 and established as well the graduate program of Masters in Clinical Audiology at the UP College of Medicine where I now work as Dean. This graduate program is one of only two in the country and is government-subsidized such that slots are limited and entry is quite competitive. It is jointly offered with the College of Allied Medical Professions.4 We consider this program to be a key element in producing the necessary healthcare workforce needed for the implementation of programs to defeat deafness in my country. The world hearing report published last year by the World Health Organization (WHO) highlighted the increasing number of people living with hearing loss and in need of services. There is of course the disproportionate burden of hearing loss in low-to middle-income countries like the Philippines.6Our publications from 2003, from a study looking at results of newborn hearing screening in the neonatal intensive unit in the hospital7,8 then to the community, thus providing the evidence for the eventual policy on UNHS that we proposed to the Department of Health (DOH) and to congress for legislation.We initially embarked on basic epidemiological studies using otoacoustic emissions testing in the hospital then in the community. We noted the age of referral at our hospital for children with hearing impairment to be at around 34 months.9 Our focus then was just providing otological clinical services so we decided to work for the establishment of the Philippine National Ear Institute (PNEI) – a research institute formed by Republic Act 9245 and part of the National Institutes of Health of the University of the Philippines – Manila.10 The PNEI laid down the researches needed for the stable foundation of a national health program focused on newborn hearing. From 2003 to 2008, we conducted several studies to establish the prevalence of bilateral permanent hearing loss in newborns both in the hospital and community settings as a prelude to the enactment of the law, and in order to defend having a program on newborn hearing, we conducted a cost-analysis of hospital-based universal newborn hearing screening.11 Notably in 2007, a population-based study showed the prevalence of bilateral profound Congenital Hearing Loss at 1.4 per 1000 births.12 This translates to more than 3,000 babies annually or 8 babies per day who may be profoundly deaf in my country.13 If there were proper intervention for a child with hearing impairment, the cost of treating hearing translates to a lifetime savings of about 80,000 dollars or about PhP 4.3M for the patient’s family. The government and the family would have spent about PhP 4.3 M to raise, educate, and support a deaf-mute child to adulthood. This was presented to the Senate of the Philippines and highlighted during the Inaugural Congress of the ASEAN Academy of Neuro-Oto-Audiology (AANOA). This was supported by Senator Loren Legarda, PNEI Director Dr. Generoso Abes, AANOA founding member Dr. Helmi Balfas, IFOS Regional Secretary Chong Sun Kim, PSOHNS President Gil Vicente, AANOA President Dato Lokman Saim, and Hearing International Secretary Dr. Norberto Martinez (Figure 2). Mandating NHS in the country also entailed involving stakeholders, including otolaryngologists from the different regions who committed to convince their local officials and local hospital administrators the need for instituting these newborn hearing screening programs. After we had the local data at hand, the PSOHNS created a task force on NHS and crafted a position statement on the need for UNHS. As then Vice President, we drafted the position paper that will be presented to Congress while at the same time seeking support from the Department of Health under DOH Secretary Francisco Duque who agreed that Philhealth should be able to support this program when enacted into law. A Technical Working Group was formed, gathering all stakeholders and service providers. Multiple meetings were held, groundwork for launch, and implementation of newborn hearing screening program were instituted with ten Collaboration for Newborn Hearing Screening Advocacy (CONHScA) annual symposia with otolaryngology, audiology, and other hearing screening advocates all over the country.14 (Figure 3). On August 12, 2009, President Gloria Macapagal-Arroyo signed RA 9709, an act that established universalnewborn hearing screening program for the prevention, early diagnosis, and intervention of hearing loss.15 On the modality to be used, reporting, accreditation and training, monitoring and evaluation, and most especially  costing of the services and financing for sustainability were also done. We advocated for legislation on UNHS, and once ratified, developed a national program with the Department of Health as lead agency and continued with policy implementation as part of a national technical working group under the DOH. This led to the creation of national Newborn Hearing Screening Reference Center (NHSRC) that was inaugurated in 2013 at the National Institutes of Health with Professor Cor Cremers of Radboud University Nijmegen as special guest. We also started to increase the awareness on the importance of NHS even on national television (Figure 4). Aside from the cost-effectiveness study of hospital-based newborn hearing screening program, we also looked at the budget impact of a community-based UNHSP in the Philippines from both the public payer and the societal perspectives. This study of Rivera et al. published in 201716 showed that cost effectiveness is sensitive to treatment rate, prevalence, follow-up rate, number of rehabilitation sessions, and coverage of the program. It was not sensitive to cost per rehabilitation session, cost of diagnosis with OAE and ABR, education costs, refer rates, recurrent costs, cost of machines, and sensitivity rates. From the societal perspective, the UNHSP was found to be cost-saving for the full range of parameters tested for cost of screening, amplification, education, rehabilitation, and fixed program costs. Ensuring treatment of at least 31 percent and follow-up rate of 24% for a community-based newborn hearing would likely be important benchmarks.  The technical arm of the lead agency for this program, the Department of Health, is the Newborn Hearing Screening Reference Center that gives assistance in defining and recommending NHS testing and follow-up protocols which include hearing screening methods, devices used, location, manner, and timing of newborn hearing screening testing. The current protocol uses the 2007 JCIH recommendation of 1-3-6 rule, with screening at 1 month, confirmation of hearing loss at 3 months, and appropriate intervention at 6 months of age.17 With respect to the preferred method of screening, the recent study by Neumann K et al. showed OAE as most prevalent in the country.18 Ten years ago in 2010, an initial web registry for reporting of the OAE results was formulated   up to 2014 it was used in 9 centers which allowed gathering of preliminary data on the NHS program. From the data, there was a registry card that needed manual data encoding and in order to sustain operations, a 1 USD fee was levied per registration and was reimbursable thru Philhealth that paid around 4 USD per hearing screening test done. Personnel training, device, and facility certification standards were implemented for centers that chose to perform newborn hearing screening testing. Tiered categorization of centers was also done with screening centers as Category A, screening and diagnostic centers as category B, screening, diagnostic, and essential intervention with hearing aid amplification as category C, and the highest category D for centers with genetic testing and counselling, cochlear implantation surgery and speech rehabilitation services. Recent data showed there were 1072 category A, 18 category B and C, and 9 category D centers distributed all over the country (Figure 5). While some services were initially hampered by the COVID-19 pandemic, NHSRC defined safety protocols that needed to be followed. In an updated advisory, first released in April 2020, and is still in effect to date, NHSRC emphasizes that the centers should follow hospital/institution’s procedural protocol regarding disinfection and attire. Hearing tests in infants are non-invasive and non-aerosol producing procedures. The advisory also included recommendations in terms of timing, preparation, and testing procedures. One significant development that was accelerated during the pandemic was the online adaptation of the NHS personnel certifying course that was reported in recent publications by Rozul et al.19,20 To date, there have been about 3403 trained personnel in 1099 centers with significant increase noted in 2019 compared to previous years. This was not however reflected in the report of Neumann probably due to the time when data for this publication was collected prior to 2019. From the registry alone, the percent screened in the Philippines has been reported to be at least 7-13 percent of live births from the years 2019-2021. The report from Philhealth of 800 claims for NHS from 2018-2019 is still under verification. In 2020, based on manual submission, out of 1099 facilities, 26 percent submitted reports. In 2019, 95% already submitted reports so the pandemic impacted significantly on reporting of results by excel file and paper reports (Figures 6 and 7). The program is still beset with challenges like poor compliance with data submission, loss to follow-up, poor connectivity, sustainable funding of the program from both local and national government, lack of human resources, and a need of much awareness among stakeholders regarding the importance of newborn hearing screening. In a country where 60 percent die without seeing a doctor, there is much work to do. The cost of screening equipment is a major barrier so we conceptualized a biomedical device development project working with engineers in the university to create an AABR screening device which is now on phase two with a TLR 5 early phase rating scale and will now include recruitment of more subjects and refinements for improvements. Harnessing technology and making this more affordable remain as strategies for developing a sustainable hearing screening program and is the subject of HELE, which aims to increase the rates of newborn hearing screening with novel technologies and telehealth. “Hele” stands for lullaby a mother sings to a child. We thought this as very apt for emphasizing the importance of hearing from birth for optimal development. This received a substantial phase 1 grant in 2016 and a phase 2 was launched this year for the premarket development which now stand at technology readiness level 5. It has already spawned many products like the computer-based e-learning training modules, capacity building with provision of basic OAE equipment, and many research publications. It is hoped that a pre-production HELE device can already be produced soon with validated efficacy and reproducibility of all the AABR responses in a clinical setting. With the collaboration of University of California Berkeley and UC Davis, a formidable team has been created. The electronic national newborn hearing screening registry was launched during WORLD HEARING DAY in 2022 and the usability testing results have been published by Ricalde et al.21 In the recent manual of operations and procedures, success indicators were outlined. This is aligned with the WHO standards for monitoring and evaluation, and determining success of programs. Beyond NHS, what else have we learned? Our studies on the genetic causes of the more common causes of hearing impairment such as otitis media showed a unique mutation A2ML1 that affected protease inhibitors allowing better mucosal defense of the middle ear mucosa. Our findings showed microbiome shifts and when we looked at gingivitis, this was what we found. The genetic counseling we embarked on for this indigenous community taught us clinicians many lessons. Speaking to them in their native language was important and house to house invitations were more effective.  What about genetic basis of congenital hearing loss? We have found that SLC26A4 mutations were more common than GJB2. There were novel mutations seen in our cohort suggesting the need for studies looking at genetic predisposition. We saw commonalities with Indonesia in terms of the prevalence of GJB2 mutations. From our studies on A2ML1 mutations predisposing to otitis media, we are monitoring this with ongoing study on Hispanic populations.  Meanwhile, a seed fund for a national cochlear implant program was approved by Congress and 20 children underwent surgery (Figure 8), while two centers, one in Visayas (Corazon Locsin Montelibano Memorial Regional Hospital in Bacolod) and another in Mindanao (Southern Philippines Medical Center in Davao) were capacitated. Virtual multidisciplinary meetings to discuss the cases were held and provided a model for optimizing use of resources and outcomes. The initial data from the 20 implanted children are very encouraging. There are goals of expanding this program to more beneficiaries by having a Z package for Cochlear implantation, funding from DOH medical assistance fund for indigent patients, and development of services for other implantable hearing devices at the Philippine General Hospital. Moreover, research on hearing need more support given that our studies on genetics of hearing loss among Filipinos yielded very important data on novel genes, uniqueness of our genetic pool as well as mutations predisposing to increased prevalence of otitis media among our marginalized and indigenous population.22-26 As a low- to middle-income country, these researches will need to be continued and may provide valuable lessons for similarly challenged countries in the works as we highlighted in 2017 during the United Nations World Hearing Assembly Advocacy Event on hearing health (Figure 9). The recent National Academy of Science and Technology health policy forum where Professor Xing Kuan Bu was featured as keynote lecturer gave important data on experiences on hearing health program development in China and in the world (Figure 10).  Clearly the sustainable development goals especially 3,4,8 and 10 covered by hearing health ensures equity and should be aspirational goals for national development. This is congruent with the vision of PNEI: “No Filipino shall be deprived of a functioning sense of hearing and balance.” Lastly, as the theme of this congress is East Meets West, the Philippines had a strong history of shipbuilding in an era when the galleon trade was very active and 148 of 200 ships that plied that route were ships built in the Philippines with our hardwood. Tracing therefore the history of the countries in ASEAN in particular with the Dutch, French, British, and Spanish influences, we need to dig deeper and look at genetic markers for both health and disease so that while we develop our friendship and scientific connections, history will prove that we have always been connected in so many ways and further exploration can be done in many dimensions. Charlotte M. Chiong, MD, PhDResearch Professor 12Project Leader of HeLeDean, UP College of Medicine (2018-present) _____________________________Paper presented in the Otology Rhinology Laryngology International Academic Conference, September 26, 2022, Auditorium Antonianum, Rome, Italy. Paper prepared in fulfillment of the Alfredo T. Ramirez Professorial Chair for 2022.    

Loss to follow-up in a newborn hearing screening program in Saudi Arabia

OBJECTIVES

Newborn hearing screening (NHS) program was officially initiated in Saudi Arabia in 2016. Although the rate of follow-up default is considered one of the major challenges to the NHS program, no studies have investigated the NHS rate of follow-up default and its reasons in Saudi Arabia. This study aimed to investigate the rate of follow-up default in a hospital-based NHS program and the possible reasons for it.

METHODS

All newborns who were delivered at a tertiary hospital-based NHS program between June 2020 and February 2022 were retrospectively included. The number of live births, newborns who passed NHS, newborns who referred NHS, and newborns who did not complete the appropriate screening or diagnostic stages were reviewed. In a prospective study, parents of all newborns who defaulted the follow-up on screening or diagnosis were telephonically interviewed about the reasons for their follow-up default.

RESULTS

In total, 2312 newborns were screened. Screening coverage of 96% and referral rate of 0.6% were found, which align well with the international benchmark. The follow-up default was 18%, which was higher than the benchmark. Parents of all newborns who defaulted the follow-up (n = 424) were also included. The most frequent reasons for follow-up default were related to the parents' unawareness of the recommended follow-up screening (39.5%) and their perception that follow-up was not necessary (24.7%). Coronavirus disease 2019 was also reported by 15.8% of the parents as a reason for follow-up default.

CONCLUSION

Lack of knowledge regarding recommendations made for follow-up and the importance of NHS were the most common reasons for default. Reducing follow-up defaults is essential for successful NHS programs, which can be achieved by implementing a tracking system to remind and encourage parents. Further studies are needed to evaluate the national NHS and investigate the reasons for follow-up defaults from different demographic regions in Saudi Arabia.

Hearing loss in neonates and infants

Hearing in neonates and infants is crucial for their development of language and communication skills. Unless hearing loss is appropriately managed early, it can cause a significant socioeconomic burden considering its detrimental impact on the child's development and its common nature. It is also the most common congenital sensory deficit, with an approximate incidence of 1.5 per 1,000 newborns. Its etiologies are heterogeneous: genetic causes are reportedly involved in up to 80% of cases, while congenital cytomegalovirus infection is the leading environmental factor contributing to congenital hearing loss. The introduction of newborn hearing screening using automated auditory brainstem response and/or automated otoacoustic emission in many developed countries has helped detect and manage hearing loss early. Current auditory rehabilitation options such as cochlear implantation implementing cutting-edge technologies can treat almost all degrees of hearing loss, emphasizing the importance of early hearing detection and intervention. Rapidly developing genetic diagnostic technologies and future cutting-edge treatment options, including gene therapy, will shed light on the future management of hearing loss in neonates and infants.

An Insight into Indonesia's Challenges in Implementing Newborn Screening Programs and Their Future Implications

Due to high entry barriers, countries might find it daunting to implement the NBS program, especially those just trying to start it. This review aims to discuss Indonesia's barriers that hinder newborn screening (NBS) implementation while discussing the future implications. Literature in Pubmed and Google Scholar was scoured with keywords such as "Newborn Screening", "Neonatal Screening", "Indonesia", "Asia Pacific", "Barriers", and "Challenges". We also searched for relevant references in those published articles. Grey literature, such as state regulations, informative webinars on the topics by experts regarding current situations, and press releases by the Indonesian Minister of Health (MoH), was also searched. Newborn screening is no longer considered just a laboratory test but an array of well-harmonized systems that must be orchestrated well. Some of the barriers Indonesia faces in implementing NBS are a lack of prevalence data, ethical issues, infrastructure, cost-benefit analysis, logistical issues, government support, patient issues, a lack of commitments, and a lack of healthcare workers, specialization, and training. Government support with professional advocates and support groups, proper infrastructure, and a single-payer system for NBS programs are necessary to accelerate NBS programs in Indonesia.

Various aspects of hearing loss in newborns: A narrative review

Hearing loss is considered the most common birth defect. The estimated prevalence of moderate and severe hearing loss in a normal newborn is 0.1%-0.3%, while the prevalence is 2%-4% in newborns admitted to the newborn intensive care unit. Neonatal hearing loss can be congenital (syndromic or non-syndromic) or acquired such as ototoxicity. In addition, the types of hearing loss can be conductive, sensorineural, or mixed. Hearing is vital for the acquisition of language and learning. Therefore, early detection and prompt treatment are of utmost importance in preventing the unwanted sequel of hearing loss. The hearing screening program is mandatory in many nations, especially for high-risk newborns. An automated auditory brainstem response test is used as a screening tool in newborns admitted to the newborn intensive care unit. Moreover, genetic testing and screening for cytomegalovirus in newborns are essential in identifying the cause of hearing loss, particularly, mild and delayed onset types of hearing loss. We aimed to update the knowledge on the various aspects of hearing loss in newborns with regard to the epidemiology, risk factors, causes, screening program, investigations, and different modalities of treatment.

Health Utilities of Bilateral Severe-to-Profound Hearing Loss with Assistive Devices

Hearing loss is a common sensory disorder in newborns. Early intervention with assistive devices benefits children's auditory and speech performance. This study aimed to measure the health utilities of children with bilateral severe-to-profound hearing impairment with different assistive devices. The descriptions of four hypothetical health states were developed, and their utility values were obtained from healthcare professionals via the visual analogue scale (VAS) and time trade-off (TTO) methods. Thirty-seven healthcare professionals completed the TTO interview and were included in the analysis. The mean utility scores obtained via VAS were 0.31 for no assistive devices, 0.41 for bilateral hearing aids, 0.63 for bimodal hearing, and 0.82 for bilateral cochlear implants. As for the utility scores obtained via TTO, mean values were 0.60, 0.69, 0.81, and 0.90, respectively. None of the four groups had the same VAS- or TTO-elicited utility (p < 0.001). The post hoc test results showed that the difference was significant between any two groups (all p < 0.05). In conclusion, this study elicited health utility of bilateral hearing impairment with different assistive devices using the VAS and TTO methods. The utility values obtained provide critical data for future cost-utility analysis and health technology assessment.

Retinol and Pro-Vitamin A Carotenoid Nutritional Status during Pregnancy Is Associated with Newborn Hearing Screen Results

The prenatal period is critical for auditory development; thus, prenatal influences on auditory development may significantly impact long-term hearing ability. While previous studies identified a protective effect of carotenoids on adult hearing, the impact of these nutrients on hearing outcomes in neonates is not well understood. The purpose of this study is to investigate the relationship between maternal and umbilical cord plasma retinol and carotenoid concentrations and abnormal newborn hearing screen (NHS) results. Mother-infant dyads (n = 546) were enrolled at delivery. Plasma samples were analyzed using HPLC and LC-MS/MS. NHS results were obtained from medical records. Statistical analysis utilized Mann-Whitney U tests and logistic regression models, with p ≤ 0.05 considered statistically significant. Abnormal NHS results were observed in 8.5% of infants. Higher median cord retinol (187.4 vs. 162.2 μg/L, p = 0.01), maternal trans-β-carotene (206.1 vs. 149.4 μg/L, p = 0.02), maternal cis-β-carotene (15.9 vs. 11.2 μg/L, p = 0.02), and cord trans-β-carotene (15.5 vs. 8.0 μg/L, p = 0.04) were associated with abnormal NHS. Significant associations between natural log-transformed retinol and β-carotene concentrations and abnormal NHS results remained after adjustment for smoking status, maternal age, and corrected gestational age. Further studies should investigate if congenital metabolic deficiencies, pesticide contamination of carotenoid-rich foods, maternal hypothyroidism, or other variables mediate this relationship.

Translation, adaptation, and validation of the Arabic version of the meaningful auditory integration scale

OBJECTIVES

The main objectives of this study were to translate and adapt the infant-toddler meaningful integration scale (IT-MAIS) into Arabic and to establish the psychometric properties of the translated scale in children with a cochlear implant.

METHODS

The translation and cross-cultural adaptation of this questionnaire were completed in multiple steps and following standard translation protocols. In total, twenty-eight parents of young cochlear implant recipients completed IT-MAIS. Data were collected postoperatively and at 3-, 6-, 9-, and 12-month post-device activation. Data were examined for the validity and reliability of the scale. The internal consistency and reliability of the scale were analyzed using Cronbach α, split-half reliability, and the corrected item-total correlation coefficients.

RESULTS

Findings demonstrated that the scale exhibited good face and content validity, suggesting that the scale is a one-dimensional measure. Additionally, the reliability analysis for the scale indicated high reliability and correlation among test items. IT-MAIS scores consistently improved over time for all participants and this improvement. correlated negatively with the duration of deafness.

CONCLUSION

Current findings indicated that the translated Arabic version of the IT-MAIS scale could serve as a valid instrument for assessing the development of auditory skills in Arabic-speaking children with cochlear implants.

Global and regional prevalence of disabilities among children and adolescents: Analysis of findings from global health databases

Objective

The United Nations' Sustainable Development Goals (SDGs) require population-based data on children with disabilities to inform global policies and intervention programs. We set out to compare the prevalence estimates of disabilities among children and adolescents younger than 20 years as reported by the world's leading organizations for global health statistics.

Methods

We purposively searched the disability reports and databases of the United Nations Children's Fund (UNICEF), the World Health Organization (WHO), the World Bank and the Global Burden of Diseases (GBD) Study. We analyzed the latest disability data reported by these organizations since 2015. We examined the methodologies adopted in generating the reported prevalence estimates and evaluated the degree of agreement among the data sources using Welch's test of statistical difference, and the two one-sided t-test (TOST) for statistical equivalence.

Results

Only UNICEF and GBD provided the most comprehensive prevalence estimates of disabilities in children and adolescents. Globally, UNICEF estimated that 28.9 million (4.3%) children aged 0-4 years, 207.4 million (12.5%) children aged 5-17 years and 236.4 million (10.1%) children aged 0-17 years have moderate-to-severe disabilities based on household surveys of child functional status. Using the UNICEF estimated prevalence of 10.1%, approximately 266 million children aged 0-19 years are expected to have moderate-to-severe disabilities. In contrast, GBD 2019 estimated that 49.8 million (7.5%) children aged under 5 years, 241.5 million (12.6%) children aged 5-19 years and 291.3 million (11.3%) children younger than 20 years have mild-to-severe disabilities. In both databases, Sub-Saharan Africa and South Asia accounted for more than half of children with disabilities. A comparison of the UNICEF and GBD estimates showed that the overall mean prevalence estimates for children under 5 years were statistically different and not statistically equivalent based on ±3 percentage-point margin. However, the prevalence estimates for children 5-19 years and < 20 years were not statistically different and were statistically equivalent.

Conclusion

Prevalence estimates of disabilities among children and adolescents generated using either functional approach or statistical modeling appear to be comparable and complementary. Improved alignment of the age-groups, thresholds of disability and the estimation process across databases, particularly among children under 5 years should be considered. Children and adolescents with disabilities will be well-served by a variety of complementary data sources to optimize their health and well-being as envisioned in the SDGs.

Newborn Screening by Genomic Sequencing: Opportunities and Challenges

Newborn screening for treatable disorders is one of the great public health success stories of the twentieth century worldwide. This commentary examines the potential use of a new technology, next generation sequencing, in newborn screening through the lens of the Wilson and Jungner criteria. Each of the ten criteria are examined to show how they might be applied by programmes using genomic sequencing as a screening tool. While there are obvious advantages to a method that can examine all disease-causing genes in a single assay at an ever-diminishing cost, implementation of genomic sequencing at scale presents numerous challenges, some which are intrinsic to screening for rare disease and some specifically linked to genomics-led screening. In addition to questions specific to routine screening considerations, the ethical, communication, data management, legal, and social implications of genomic screening programmes require consideration.

Language-Independent Hearing Screening - Increasing the Feasibility of a Hearing Screening Self-Test at School-Entry

A tablet-based language-independent self-test involving the recognition of ecological sounds in background noise, the Sound Ear Check (SEC), was adapted to make it feasible for young children. Two experiments were conducted. The first experiment investigated the SEC's feasibility, as well as its sensitivity and specificity for detecting childhood hearing loss with a monaural adaptive test procedure. In the second experiment, the SEC sounds, noise, and test format were adapted based on the findings of the first experiment. The adaptations were combined with three test procedures, one similar to the one used in Experiment 1, one presenting the sounds dichotically in diotic noise, and one presenting all the sounds with a fixed signal-to-noise ratio and a stopping rule. Results in young children show high sensitivity and specificity to detect different grades of conductive and sensorineural hearing loss (70-90%). When using an adaptive, monaural procedure, the test duration was approximately 6 min, and 17% of the results obtained were unreliable. Adaptive staircase analyses showed that the unreliable results probably occur due to attention/motivation loss. The test duration could be reduced to 3-4 min with adapted test formats without decreasing the test-retest reliability. The unreliable test results could be reduced from 17% to as low as 5%. However, dichotic presentation requires longer training, reducing the dichotic test format's feasibility.