Aetiological diagnosis of child deafness: CODEPEH recommendations

Enlarged vestibular aqueduct as a cause of postneonatal deafness

INTRODUCTION

The enlarged vestibular aqueduct (EVA) is the most frequent malformation of the inner ear associated with sensorineural hearing loss (5-15%). It exists when the diameter in imaging tests is greater than 1.5 mm at its midpoint. The association between hearing loss and EVA has been described in a syndromic and non-syndromic manner. It can appear as a familial or isolated form and the audiological profile is highly variable. The gene responsible for sensorineural hearing loss associated with EVA is located in the same region described for Pendred syndrome, where the SCL26A4 gene is located.

OBJECTIVE

To describe a series of children diagnosed with EVA in order to study their clinical and audiological characteristics, as well as the associated genetic and vestibular alterations.

METHOD

Retrospective study of data collection of children diagnosed with EVA, from April 2014 to February 2023.

RESULTS

Of the 17 cases, 12 were male and 5 were female. 5 of them were unilateral and 12 bilateral. In 5 cases, a cranial traumatism triggered the hearing loss. Genetic alterations were detected in 3 cases: 2 mutations in the SCL26A4 gene and 1 mutation in the MCT1 gene. 13 patients (76.5%) were rehabilitated with hearing aids and 9 of them required cochlear implantation.

DISCUSSION

The clinical importance of AVD lies in the fact that it is a frequent finding in the context of postneonatal hearing loss. It is convenient to have a high suspicion to diagnose it with imaging tests, to monitor its evolution, and to rehabilitate early.

Genetic diagnosis of childhood sensorineural hearing loss

INTRODUCTION

Congenital/early-onset sensorineural hearing loss (SNHL) is one of the most common hereditary disorders in our environment. There is increasing awareness of the importance of an etiologic diagnosis, and genetic testing with next-generation sequencing (NGS) has the highest diagnostic yield. Our study shows the genetic results obtained in a cohort of patients with bilateral congenital/early-onset SNHL.

MATERIALS AND METHODS

We included 105 children with bilateral SNHL that received genetic testing between 2019 and 2022. Genetic tests were performed with whole exome sequencing, analyzing genes related to hearing loss (virtual panel with 244 genes).

RESULTS

48% (50/105) of patients were genetically diagnosed. We identified pathogenic and likely pathogenic variants in 26 different genes, and the most frequently mutated genes were GJB2, USH2A and STRC. 52% (26/50) of variants identified produced non-syndromic hearing loss, 40% (20/50) produced syndromic hearing loss, and the resting 8% (4/50) could produce both non-syndromic and syndromic hearing loss.

CONCLUSIONS

Genetic testing plays a vital role in the etiologic diagnosis of bilateral SNHL. Our cohort shows that genetic testing with NGS has a high diagnostic yield and can provide useful information for the clinical workup of patients.

Universal neonatal hearing screening and delayed hearing loss or late-developmental hearing loss

OBJECTIVE

To determine the percentage of children with permanent bilateral postnatal hearing loss in order to study its incidence, related risk factors, diagnosis and treatment.

METHODS

Retrospective study to collect data on children diagnosed with hearing loss outside the neonatal period in the Hearing Loss Unit of the Hospital Universitario Central de Asturias, from April 2014 to April 2021.

RESULTS

52 cases met the inclusion criteria. The detection rate of congenital hearing loss in the neonatal screening programme in the same study period was 1.5 children per thousand newborns per year, adding postnatal hearing loss results in a rate of infant bilateral hearing loss of 2.7 children per thousand (55.5% and 44.4% respectively). Thirty-five children presented risk factors for hearing loss, of which 23 were at retrocochlear risk. The mean age at referral was 91.9 (18-185) months. Hearing aid fitting was indicated in 44 cases (84.6%). Cochlear implantation was indicated in eight cases (15.4%).

DISCUSSION

Although congenital hearing loss accounts for the majority of childhood deafness, postnatal hearing loss has a significant incidence. This may be mainly due to: (1) that hearing impairment may arise in the first years of life, (2) that mild hearing loss as well as hearing loss in severe frequencies are undetectable by neonatal screening in some cases, (3) that some children may have false negative results.

CONCLUSION

postnatal hearing loss requires identification of risk factors and long-term follow-up of children with hearing loss, as it needs to be detected and treated early.

Keypoints to Successful Newborn Hearing Screening. Thirty Years of Experience and Innovations

Congenital deafness is a major pediatric problem, affecting about 1.5–3 per 1000 newborns. The early treatment through cochlear implantation and auditory rehabilitation has been a historic milestone. Early diagnosis of congenital deafness is an essential requirement to obtain the best results, which is achieved through neonatal screening, a diagnostic practice that we began systematically at the Hospital Clínico in Valencia (Spain) 30 years ago. Neonatal hearing screening is successful in most developed countries. Its implementation has been slow due to the multiple difficulties that its universal application entails since it involves several health professionals and must be carried out, in a short time interval after birth. In addition, it must have a good performance that prevents the overload of other services and that requires experience and continuous adjustments in search of proper protocols. The aim of this review is to shed some light on some key points of neonatal hearing screening, highlighting our experience in the solutions to common problems. We will discuss about techniques, protocols and neonatal or nutritional factors that can influence the screening results. To a summary of our work, an update on the subject is provided with the intention of sharing experiences and facilitating the start-up of the new units.

New-born Hearing Screening Programmes in 2020: CODEPEH Recommendations

Programmes for early detection of congenital hearing loss have been successfully implemented mainly in developed countries, after overcoming some conceptual errors argued against their implementation and some criticism of their efficacy. However, some difficulties and weaknesses are still identified in these programmes: the detection of late-onset hearing loss and the percentage of children who did not pass the screening and did not complete the process of diagnosis and treatment, these being cases that are lost in the process. The purpose of this Document is to analyse these problems to determine areas for improvement and to emphasize one of the basic principles for the success of the programmes: continuous training for the interdisciplinary team. The result of the review process carried out by CODEPEH has been drafted as Recommendations for updating the Programmes with the evidence of the last decade, including advances in screening technology, the impact of the present knowledge on congenital infection by cytomegalovirus, genetic hearing loss research and control systems of lost to follow-up cases, treatment and follow up.

Early Detection Programmes for Child Hearing Loss in Spain: Current Practices

INTRODUCTION AND OBJECTIVE

In 2003, The Ministry of Health and Consumption, together with the Autonomous Communities (CCAA), approved a minimum and basic document concerning the establishment of Early Hearing Detection and Intervention State Programmes. Since then, the Commission for the early detection of hearing loss (CODEPEH) has made several updates and recommendations to improve these programmes. The objective of this study is to carry out a comparative analysis of how the CCAA established their Early Hearing Detection and Intervention programs and if they integrate the recommendations made by CODEPEH until 2017.

MATERIAL AND METHOD

The programmes (or related documents) of 16 CCAA available on line or paper are reviewed RESULTS: The 16 Early Hearing Detection and Intervention strategies analyzed are different, either in the number of test to be performed, the time in which they are performed or the techniques used. More than a third of these programmes were published before 2010 and have not been updated. Otoacoustic emissions is the chosen technique as the first screening test in nine of the 16 CCAA. Only one CCAA incorporates the salivary polymerase chain reaction test for cytomegalovirus in children with altered screening test.

CONCLUSION

All CCAA perform Early Hearing Detection and Intervention programmes but the heterogeneity does not allow drawing reliable conclusions about the result of the screening process and it would be necessary to aim for unification with the elaboration of a national programme and an integrated general database.

Clinical utility of next-generation sequencing in the aetiological diagnosis of sensorineural hearing loss in a Childhood Hearing Loss Unit

INTRODUCTION

Sensorineural hearing loss (SNL) is the most prevalent sensory deficit in our environment. Next generation genomic sequencing (NGS) enables an aetiological diagnosis in a high percentage of patients. Our pilot study shows the results of the systematic application of NGS in a Childhood Hearing Loss Unit, as well as its implications for the clinical management of patients and their families.

MATERIAL AND METHOD

We included 27 patients diagnosed with SNL between 2014 and 2017, in which an environmental cause was ruled out. The genetic test consisted of a panel of genes analyzed by NGS (OTOgenicsTM panel). This panel has been designed to include genes associated with sensorineural or mixed hearing loss, early onset or late, syndromic and non-syndromic, regardless of their inheritance pattern.

RESULTS

A genetic diagnosis was obtained in 56% (15/27) of the patients (62% in the case of bilateral SNL). Of the patients, 5/27 (19%) presented pathogenic variants in the GJB2 gene and the rest pathogenic and / or probably pathogenic variants in other genes associated with isolated SNL (PR2X2, TECTA and STRC), with syndromic SNL (CHD7, GATA3, COL4A5, MITF and SOX10) or with syndromic and non-syndromic SNL (BSND, ACTG1 and CDH23).

DISCUSSION

The aetiological diagnosis of SNL is a challenge in clinical practice. Our series demonstrates that it is possible to implement genetic diagnosis in the care routine and that this information has prognostic and therapeutic implications.

Comprehensive genomic diagnosis of non-syndromic and syndromic hereditary hearing loss in Spanish patients

BACKGROUND

Sensorineural hearing loss (SNHL) is the most common sensory impairment. Comprehensive next-generation sequencing (NGS) has become the standard for the etiological diagnosis of early-onset SNHL. However, accurate selection of target genomic regions (gene panel/exome/genome), analytical performance and variant interpretation remain relevant difficulties for its clinical implementation.

METHODS

We developed a novel NGS panel with 199 genes associated with non-syndromic and/or syndromic SNHL. We evaluated the analytical sensitivity and specificity of the panel on 1624 known single nucleotide variants (SNVs) and indels on a mixture of genomic DNA from 10 previously characterized lymphoblastoid cell lines, and analyzed 50 Spanish patients with presumed hereditary SNHL not caused by GJB2/GJB6, OTOF nor MT-RNR1 mutations.

RESULTS

The analytical sensitivity of the test to detect SNVs and indels on the DNA mixture from the cell lines was > 99.5%, with a specificity > 99.9%. The diagnostic yield on the SNHL patients was 42% (21/50): 47.6% (10/21) with autosomal recessive inheritance pattern (BSND, CDH23, MYO15A, STRC [n = 2], USH2A [n = 3], RDX, SLC26A4); 38.1% (8/21) autosomal dominant (ACTG1 [n = 3; 2 de novo], CHD7, GATA3 [de novo], MITF, P2RX2, SOX10), and 14.3% (3/21) X-linked (COL4A5 [de novo], POU3F4, PRPS1). 46.9% of causative variants (15/32) were not in the databases. 28.6% of genetically diagnosed cases (6/21) had previously undetected syndromes (Barakat, Usher type 2A [n = 3] and Waardenburg [n = 2]). 19% of genetic diagnoses (4/21) were attributable to large deletions/duplications (STRC deletion [n = 2]; partial CDH23 duplication; RDX exon 2 deletion).

CONCLUSIONS

In the era of precision medicine, obtaining an etiologic diagnosis of SNHL is imperative. Here, we contribute to show that, with the right methodology, NGS can be transferred to the clinical practice, boosting the yield of SNHL genetic diagnosis to 50-60% (including GJB2/GJB6 alterations), improving diagnostic/prognostic accuracy, refining genetic and reproductive counseling and revealing clinically relevant undiagnosed syndromes.

Survey on the knowledge of cochlear implant indication in the treatment of hearing loss in Spain

INTRODUCTION

This study aims to analyse the knowledge of cochlear implant (CI) candidacy criteria of otorhinolaryngology specialists in Spain, and from the results, consider whether it is necessary to implement training measures aimed at improving knowledge in this area.

MATERIAL AND METHODS

A questionnaire was designed for measuring the level of knowledge of cochlear implant candidacy criteria (CI) in people with hearing loss. The questionnaire collected the demographic data of the respondents and their knowledge on the conventional and emergency indications for CI, technical characteristics of CI and results in the implanted population.

RESULTS

A total of 222 Spanish specialists in otorhinolaryngology answered the questionnaire (10.29% of the sample surveyed).

CONCLUSIONS

The 50% of all respondents showed a medium-high knowledge about CI. Epidemiological data suggest that a high percentage of adults with postlocutive deafness and candidates for a CI are not referred for treatment. The lack of knowledge about the criteria for the indication of CI by otorhinolaryngology specialists may contribute to inadequate guidance of patients who are potential candidates for CI. The greatest shortcomings are found in the most emergency indications for a CI. Among otorhinolaryngology professionals, the greatest knowledge about CI is found in those who work in tertiary hospitals in the areas of otology and otoneurology, either in the public or private sector. This study suggests that training on CI should be increased for otorhinolaryngology professionals, especially for general otorhinolaryngologists.