Inner Ear Dysplasia is Common in Children With Down Syndrome (trisomy 21)

Electrophysiological findings of brainstem auditory evoked potentials in infants with down syndrome: A systematic review and meta-analysis

OBJECTIVE

to summarize the evidence on the electrophysiological findings in the auditory brainstem response (ABR) in infants with DS.

MATERIAL AND METHODS

This is a systematic review study, whose protocol was registered in the International Prospective Register of Systematic Reviews (PROSPERO CRD42023424139) and conducted in accordance with the recommendations of the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). Observational studies were included: cross-sectional and cohort studies that performed ABR evaluation in infants with DS up to two years of age, which had their results compared with normal infants, of the same age group. The search for studies was performed in the following databases: PubMed, LILACS, Scopus, CINHAL, Web of Science, Scielo, Embase and LIVIVO, and in the gray literature: Google Scholar and Proquest. There were no restrictions on language or publication date. The methodological quality of the included studies was assessed using the JBI (Joanna Briggs Institute) checklist. Phases 1 (reading of titles and abstracts) and 2 (reading in full), data extraction, assessment of methodological quality and certainty of evidence were performed independently by the reviewers. Existing disagreements were resolved in a consensus meeting.

RESULTS

A total of 494 articles were obtained, which after removal of duplicates and independent analysis by the reviewers, ten studies were selected for qualitative synthesis and four studies were selected for meta-analysis. There was heterogeneity between the effects observed in the ABR parameters (I2 = 78 %) with an overall pooled effect size of -0.05 (95 % confidence interval of -0.13-0.03; p = 0.22) indicating no significant difference in ABR responses between groups. The certainty of the evidence assessed by GRADE was considered very low due to inconsistency and imprecision.

CONCLUSION

The results of the meta-analysis indicate that there are no significant diferences in ABR parameters, including waves I, III, and V and the I - V interpeak interval, between infants with and without DS up to two years of age. However, the limitations found, such as methodological heterogeneity, small sample sizes and variability in the age range of the participants, generated uncertainty in the results. Therefore, the certainty of the evidence was classified as very low, according to the GRADE methodology.

Incomplete partition type II in its various manifestations: isolated, in association with EVA, syndromic, and beyond; a multicentre international study

PURPOSE

Incomplete partition type II (IP-II) is characterized by specific histological features and radiological appearance. It may occur in isolation or in association with an enlarged vestibular aqueduct (EVA). Among those with IP-II and EVA, a subset has a diagnosis of Pendred syndrome. This study aimed to explore the prevalence of isolated IP-II, IP-II with EVA, and cases with a genetic or syndromic basis in our cohort.

METHODS

From a large, multicentre database of dysplastic cochleae (446 patients, 892 temporal bones), those with imaging features of IP-II were examined in detail, including whether there was a genetic or syndromic association.

RESULTS

A total of 78 patients with IP-II were identified. Among these, 55 patients had bilateral IP-II and EVA (only 12 with typical Mondini triad), 8 with bilateral IP-II and normal VA, 2 with bilateral IP-II and unilateral EVA, and 13 with unilateral IP-II (9 with unilateral EVA). Among the group with bilateral IP-II and bilateral EVA in whom genetic analysis was available, 14 out of 29 (48%) had SLC26A4 mutations and a diagnosis of Pendred syndrome, 1 had a FOXI1 mutation, and a few other genetic abnormalities; none had KCNJ10 pathogenic variants.

CONCLUSION

Bilateral IP-II-bilateral EVA may be seen in the context of Pendred syndrome (SLC26A4 or FOXI1 mutations) but, in the majority of our cohort, no genetic abnormalities were found, suggesting the possibility of unknown genetic associations. IP-II in isolation (without EVA) is favored to be genetic when bilateral, although the cause is often unknown.

The child who lived: Down syndrome among Neanderthals?

Caregiving for disabled individuals among Neanderthals has been known for a long time, and there is a debate about the implications of this behavior. Some authors believe that caregiving took place between individuals able to reciprocate the favor, while others argue that caregiving was produced by a feeling of compassion related to other highly adaptive prosocial behaviors. The study of children with severe pathologies is particularly interesting, as children have a very limited possibility to reciprocate the assistance. We present the case of a Neanderthal child who suffered from a congenital pathology of the inner ear, probably debilitating, and associated with Down syndrome. This child would have required care for at least 6 years, likely necessitating other group members to assist the mother in childcare.

Syndromic Hearing Loss in Children

Pattern recognition of specific temporal bone radiological phenotypes, in association with abnormalities in other organ systems, is critical in the diagnosis and management of syndromic causes of hearing loss. Several recent publications have demonstrated the presence of specific radiological appearances, allowing precise genetic and/or syndromic diagnosis, in the right clinical context. This review article aims to provide an extensive but practical guide to the radiologist dealing with syndromic causes of hearing loss.

Cochlear Implantation: Systematic Approach to Preoperative Radiologic Evaluation

Sensorineural hearing loss results from abnormalities that affect the hair cells of the membranous labyrinth, inner ear malformations, and conditions affecting the auditory pathway from the cochlear nerve to the processing centers of the brain. Cochlear implantation is increasingly being performed for hearing rehabilitation owing to expanding indications and a growing number of children and adults with sensorineural hearing loss. An adequate understanding of the temporal bone anatomy and diseases that affect the inner ear is paramount for alerting the operating surgeon about variants and imaging findings that can influence the surgical technique, affect the choice of cochlear implant and electrode type, and help avoid inadvertent complications. In this article, imaging protocols for sensorineural hearing loss and the normal inner ear anatomy are reviewed, with a brief description of cochlear implant devices and surgical techniques. In addition, congenital inner ear malformations and acquired causes of sensorineural hearing loss are discussed, with a focus on imaging findings that may affect surgical planning and outcomes. The anatomic factors and variations that are associated with surgical challenges and may predispose patients to periprocedural complications also are highlighted. ^© RSNA, 2023 Quiz questions for this article are available through the Online Learning Center. Online supplemental material and the slide presentation from the RSNA Annual Meeting are available for this article.

Otolaryngologic Disease in Down syndrome

As the most common human chromosomal abnormality, Trisomy 21 is a condition that many otolaryngologists and likely all pediatric otolaryngologists will encounter during their careers. There are several considerations regarding airway obstruction, otologic conditions, anesthetic implications, and endocrine disorders that will impact the treatment of these patients. Further, there is increasing literature supporting the use of early instrumental assessment of swallowing, drug-induced sleep endoscopy at the time of first surgical intervention for sleep apnea, consideration of concurrent upper and lower airway evaluation, and early otologic management including potential surgical hearing rehabilitation.

Analysis of Newborn Hearing Screening Test Results of Children with Down Syndrome

Aim:

The aim of this study was to analyze newborn hearing screening test results of children with Down syndrome (DS).

Methods:

The files of 84 children with DS and 84 healthy children (control group) admitted to the Pediatrics Polyclinics of the Konya Training and Research Hospital between January 2017 and June 2020 were retrospectively reviewed.

Results:

Thirty-one of the 84 babies with DS were female (36.9%), and 53 were male (63.1%); 37 of the 84 babies in the control group were female (44%), and and 47 were male (56%) (P = .346). Fortty-eight (57.1%) of the 84 babies with DS and 17 (20.2%) of the 84 babies in the control group failed the first screening test (P < .001). It was determined that 24 (50%) of the 48 infants with DS who failed the first test also failed the second test and were referred, and all 17 infants in the control group who failed the first test passed the second test (P < .001). There was no significant difference in terms of birth weight, gestational week, and maternal age between infants with DS who failed and passed after the second screening test (P > .05 for all).

Conclusion:

Our study shows that birth weight, gestational age, and maternal age do not pose an additional risk for hearing loss in DS babies who do not have known risk factors for hearing loss.

Figure-based speech perception test: applicability in children with Down syndrome

PURPOSE

To verify the applicability of the picture-based speech perception test in children with Down syndrome.

METHODS

Observational, descriptive, prospective study, carried out at two speech therapy centers, approved by their Research Ethics Committees under numbers 82522217.5.0000.5440 and 79510317.8.0000.5257. A total of 41 children with Down syndrome, of both sexes, aged 2 years to 10 years and 11 months participated. They were divided into three groups: GI (2 years to 4 years and 11 months); GII (5 years to 7 years and 11 months); GIII (8 years to 10 years and 11 months). We verified their medical history and carried out meatoscopy, pure-tone threshold audiometry, speech recognition threshold test with pictures, and immittance tests. For statistical analysis, we used Fisher's Exact Test with the 5% significance level. Results: The analysis of hits and misses in relation to chronological age revealed significance in seven words: "ice", "knife", "cow", "key", "mouse", "dog", and "sun". We then analyzed this study participants' performance in the speech test with pictures and those in the study that developed and validated this test. Comparing the percentage of correct answers in the two groups, we found that the words with the most correct answers were "hand", "house", and "frog". Conclusion: The test applied in this study provides a clear and objective interpretation of the results, regardless of the child's verbal production.

Perspective on the Development of a Large-Scale Clinical Data Repository for Pediatric Hearing Research

The use of "big data" for pediatric hearing research requires new approaches to both data collection and research methods. The widespread deployment of electronic health record systems creates new opportunities and corresponding challenges in the secondary use of large volumes of audiological and medical data. Opportunities include cost-effective hypothesis generation, rapid cohort expansion for rare conditions, and observational studies based on sample sizes in the thousands to tens of thousands. Challenges include finding and forming appropriately skilled teams, access to data, data quality assessment, and engagement with a research community new to big data. The authors share their experience and perspective on the work required to build and validate a pediatric hearing research database that integrates clinical data for over 185,000 patients from the electronic health record systems of three major academic medical centers.

Opportunities, barriers, and recommendations in down syndrome research

BACKGROUND

Recent advances in medical care have increased life expectancy and improved the quality of life for people with Down syndrome (DS). These advances are the result of both pre-clinical and clinical research but much about DS is still poorly understood. In 2020, the NIH announced their plan to update their DS research plan and requested input from the scientific and advocacy community.

OBJECTIVE

The National Down Syndrome Society (NDSS) and the LuMind IDSC Foundation worked together with scientific and medical experts to develop recommendations for the NIH research plan.

METHODS

NDSS and LuMind IDSC assembled over 50 experts across multiple disciplines and organized them in eleven working groups focused on specific issues for people with DS.

RESULTS

This review article summarizes the research gaps and recommendations that have the potential to improve the health and quality of life for people with DS within the next decade.

CONCLUSIONS

This review highlights many of the scientific gaps that exist in DS research. Based on these gaps, a multidisciplinary group of DS experts has made recommendations to advance DS research. This paper may also aid policymakers and the DS community to build a comprehensive national DS research strategy.

Temporal bone dysplasia in Coffin-Siris syndrome

We report a child, diagnosed with Coffin-Siris syndrome (CSS), with chronic right otorrhoea. CT and DR-MRI were performed to further investigate, diagnose and determine relevant surgical anatomy. CT temporal bones assessment was performed, and the measurements compared with previously published data for normal temporal bone anatomy. These comparisons highlighted various differences which were not initially expected; it showed that there were multiple inner ear abnormalities in addition to middle ear disease. This case highlights the importance of considering temporal bone abnormalities in all children with CSS or any dysmorphia, when they may require mastoid procedures. Reviewing the management of this case provides relevant learning opportunities for both primary, secondary and tertiary care institutions.

Clinical genetics, practice, and research of deafblindness: From uncollected experiences to the national registry in Japan

Deafblindness is a condition of combined vision and hearing loss that is extremely rare in children and young adults, as well as being a highly heterogeneous condition, with over 70 specific etiologies. Due to these features, sporadic clinical experiences have not been collated, which has hampered medical progress. Genetics plays a major role in the pathogenesis of deafblindness in children and young adults, with more than 50 hereditary syndromes and disorders associated with the condition, including CHARGE, Usher, Down, Stickler, and Dandy-Walker syndromes, which are the most common. Clinical diagnosis of deafblindness is often difficult, and a significant proportion of patients are undiagnosed. No curative therapy is currently available for the majority of patients with hereditary deafblindness; however, experimental studies using animal models have shown promising results by targeting specific genes that cause vision or hearing loss. In Japan, the Rare Disease Data Registry of Japan (RADDAR-J) has been established as a national registry of rare and intractable diseases. Diseases of deafblindness have been elected as a disease category in RADDAR-J. Currently, clinical and genomic data are being collected and analyzed using this system, with the aim of generating an overview of deafblindness to improve medical practice.

Temporal bone and intracranial abnormalities in syndromic causes of hearing loss: an updated guide

PURPOSE

To describe in detail the temporal bone and brain findings in both common and rare syndromic causes of hearing loss, with the purpose of broadening among radiologists and enhance the current understanding of distinct imaging features in paediatric patients with syndromic hearing loss.

METHODS

A detailed search of electronic databases has been conducted, including PubMed, Ovid Medline, Scopus, Cochrane Library, Google Scholar, National Institute for Health and Care Excellence (NICE), Embase, and PsycINFO.

RESULTS

Syndromic causes of hearing loss are characterised by different and sometimes specific abnormalities in the temporal bone.

CONCLUSION

A complete knowledge of the image findings in the temporal bones, brain, skull and other body regions is critical for the optimal assessment and management of these patients.

Cochlear implants in eight children with Down Syndrome - Auditory performance and challenges in assessment

OBJECTIVES

A small proportion of children with Down Syndrome (DS) have severe to profound hearing loss and may potentially benefit from a cochlear implant (CI). Evidence on outcomes in DS is very limited, and there is a need for further investigation to provide a basis for clinical evaluation of candidates and outcomes. This study aims to explore outcomes of CI in children with DS in Norway.

METHODS

Data on all children with DS and CI in Norway were collected from the CI registry and patients' records at the national pediatric CI center. Main outcome measures were: use of CI, Category of Auditory Performance (CAP), Speech Intelligibility Rate (SIR), and parents' and caregivers' views of the benefits of CI.

RESULTS

Eight children with DS have received CI in Norway, all bilaterally. The outcomes varied greatly. All children used their CIs, and all of them responded to environmental sounds. Four children reached CAP score 5 after several years of use, (i.e., they understand phrases without lip reading). All children scored at least 2, (i.e., responds to speech sounds). One child reached a SIR score of 3, (i.e. connected speech is intelligible to experienced listeners). The rest of the children reached SIR scores of 1 or 1-2, (i.e., connected speech is unintelligible). Without exception, parents had an entirely positive attitude to their children using a CI. Co-morbidity and middle ear disease frequently delayed implantation.

CONCLUSIONS

Our experience with CI in children with DS is positive. However, CI cannot replace other types of communication for these children, and it is important to give parents realistic expectations prior to surgery. Outcomes might be considered limited when evaluated with instruments for testing auditory performance and speech intelligibility constructed for children without additional disabilities. We do not believe that such outcomes reflect the benefit in real life.

Children with unilateral cochlear nerve canal stenosis have bilateral cochleovestibular anomalies

OBJECTIVES/HYPOTHESIS

To investigate the cochleovestibular apparatus bilaterally in children with isolated unilateral bony cochlear nerve canal (bCNC) stenosis.

STUDY DESIGN

Retrospective review.

METHODS

Imaging studies of children with unilateral bCNC stenosis (<1.0 mm) on computed tomography imaging (N = 36) were compared with controls imaged due to trauma without temporal bone injury (N = 32). Twenty-six measurements were obtained in each ear, assessing the bony internal auditory canal (IAC), cochlea, and vestibular end-organs, and were analyzed using one-way analysis of variance for intersubject comparisons and paired t tests for intrasubject comparisons with a Bonferroni adjustment for multiple comparisons (P = .0006).

RESULTS

Patients with bCNC stenosis had a smaller IAC (P < .000) and cochlea (P < .000) on the stenotic side as compared with controls. Although the vestibular end-organ was also smaller in bCNC ears, this difference was not significant. The contralateral ear also had a smaller bCNC (P < .000) and cochlea (P < .000) as compared with controls, although to a lesser degree than the stenotic side.

CONCLUSIONS

Children with unilateral bCNC stenosis have abnormal biometry of both the cochlea and the vestibular end-organ in the affected and the normal contralateral ear as compared with controls.

LEVEL OF EVIDENCE

3b Laryngoscope, 129:2403-2408, 2019.

Two Down Syndrome Patients with Bilateral Profound Hearing Loss: Case Report and Literature Review

Hearing loss is not uncommon among patients with Down syndrome (DS). It has been reported in 38–78% of the Down syndrome population. However, profound hearing loss in DS patients is rarely noticed due to its low incidence. In this article, we reported two Down syndrome patients with bilateral profound hearing loss in two cases. The first case involved an eight-year-old DS child experiencing extremely severe defects in terms of language and severe defects in terms of gross motor function, adaptability, and sociability. The second case revolved around another DS child with bilateral cochlear nerve absence. We review literature on the DS patients with hearing loss and conclude that profound sensorineural hearing loss in those patients has not received enough attention so far. We also recommend that cochlear implantation (CI) suitability assessment and timely intervention via cochlear implantation are necessary in DS patients. Besides, benefits from CI would be limited and hearing rehabilitation process could be much slower when compared with children without additional inabilities.

Characteristics and Progression of Hearing Loss in Children with Down Syndrome

OBJECTIVES

To evaluate hearing impairment in children with Down syndrome, and to describe the factors that influence the severity of hearing loss or changes in hearing over time.

STUDY DESIGN

Using the Audiological and Genetic Database (AudGenDB), audiograms of children with Down syndrome were analyzed retrospectively for type, severity, and laterality of hearing loss, as well as changes over time. Medical charts and imaging results were reviewed to identify factors influencing hearing loss.

RESULTS

Among the 1088 patients with Down syndrome included in the study, 921 had hearing loss in at least 1 ear, 91.1% had bilateral hearing loss, and 8.9% had unilateral hearing loss (1760 total ears with hearing loss). Of the ears with hearing loss, 18.8% (n = 180) had moderate or worse hearing loss. "Undefined" hearing loss and pure conductive hearing loss (CHL) were the most common types, followed by mixed hearing loss and sensorineural hearing loss (SNHL). Three-quarters (75.4%) of the children had experienced chronic otitis media or more than 2 episodes of acute otitis media. Patients with bilateral, mixed hearing loss or a history of seizures were at risk for more severe hearing loss. CHL, absence of cholesteatoma, and placement of first ear tubes before age 2 years were associated with greater improvement in hearing over time, whereas SNHL and mixed hearing loss were associated with progressive decline.

CONCLUSION

Children with Down syndrome who have bilateral, mixed hearing loss or a history of seizures are at risk for more severe hearing loss. SNHL and mixed hearing loss should not be overlooked in patients with CHL. All patients with Down syndrome will benefit from serial audiograms, especially those children with SNHL or mixed hearing loss, which is likely to worsen over time.

Characterization of upper airway obstruction using cine MRI in children with residual obstructive sleep apnea after adenotonsillectomy

OBJECTIVES/BACKGROUND

Tonsillectomy and adenoidectomy (T&A) lead to resolution of obstructive sleep apnea (OSA) in most children. However, OSA persists in about 25-40% of children. Cinematic magnetic resonance imaging (cine MRI) can aid the management of persistent OSA by localizing airway obstruction. We describe our experience in implementing and optimizing a cine MRI protocol by using a 3 Tesla MRI scanner, and the use of dexmedetomidine for sedation to improve reproducibility, safety, and diagnostic accuracy.

PATIENTS/METHODS

Patients aged 3-18 years who underwent cine MRI for the evaluation of persistent OSA after T&A and failed positive airway pressure (PAP) therapy were included. Clinical data and the apnea-hyponea index were compared with quantitative and qualitative estimates of airway obstruction from imaging sequences.

RESULTS

A total of 36 children were included with a mean age of 9.6 ± 4.6 (SD) years with 40% over 12 years of age. Two-thirds of them were boys. Seventeen out of 36 children (47%) had Down syndrome. Single site and multilevel obstruction were identified in 21 of 36 patients (58%) and in 12 of 36 patients (33%), respectively. All cine MRIs were performed without complications. Multiple regression analysis demonstrated that a combination of the minimum airway diameter and body mass index z-score best predicted OSA severity (P = 0.002).

CONCLUSIONS

Cine MRI is a sensitive, safe, and noninvasive modality for visualizing upper airway obstruction in children with persistent OSA after T&A. Accurate identification of obstruction can assist in surgical planning in children who fail PAP therapy.

Understanding Hearing and Hearing Loss in Children With Down Syndrome

PURPOSE

This study evaluated the prevalence of permanent and transient hearing loss, the use of hearing aids as a recommendation, and middle ear dysfunction in children with Down syndrome (DS) through a large multiage and ethnically diverse sample, using current audiologic testing practices.

METHOD

Retrospective analysis of data collected on 308 children with DS (168 boys, 140 girls; average age = 5.99 ± 4.88 years) who received an audiological evaluation during 2013 as part of their medical care at a large pediatric hospital.

RESULTS

Permanent hearing loss was identified in 24.9% of the children, among whom bilateral (75.4%) and conductive (33.3%) hearing losses occurred most often. Of children with DS, 22%-30% experienced a transient hearing loss, with a high incidence of middle ear pathologies from infancy until early adulthood. There were no statistical differences between ethnicity and permanent/transient hearing loss diagnosis. Twenty-three percent were current hearing aid users or had them recommended in a treatment plan.

CONCLUSIONS

The prevalence of hearing loss and abnormal middle ear status is high in the pediatric population with DS. Audiologic evaluations should follow the American Academy of Pediatrics practice guidelines to monitor this high-risk population, and amplification should be considered as an appropriate intervention option if repeated audiologic examinations reveal hearing loss.

Enlarged vestibular aqueducts and other inner-ear abnormalities in patients with Down syndrome

BACKGROUND

Histopathological anomalies of inner-ear structures in individuals with Down syndrome have been well documented; however, few studies have examined the radiological features.

METHODS

A retrospective study was conducted of temporal bone computed tomography images in 38 individuals (75 ears) with Down syndrome to evaluate the prevalence of inner-ear abnormalities and assess vestibular aqueduct widths.

RESULTS

Inner-ear anomalies were identified in 20 of the 38 individuals (52.6 per cent). Seven of the 75 temporal bones (9.3 per cent) were found to have higher than previously reported. A dilated internal auditory canal and vestibule were more common among the present study group, while prior studies have demonstrated internal auditory canal stenosis and decreased vestibule size.

CONCLUSION

Down syndrome patients exhibit a high prevalence of dysplastic inner-ear features that confer substantial risk of sensorineural hearing loss. Computed tomography is a useful screening aid to detect inner-ear abnormalities, particularly enlarged vestibular aqueducts, which cause preventable sensorineural hearing loss in this population.

Wideband reflectance in Down syndrome

OBJECTIVE

Children with Down syndrome (DS) have a high incidence of middle ear disorders and congenital abnormalities of the external, middle and inner ear. Energy reflectance (ER), a wideband acoustic immittance (WAI) measurement parameter, can measure the sound energy reflected or absorbed in the ear canal over a wider range of frequencies more efficiently and faster than conventional single-tone 226 Hz tympanometry. The aim of the present study was to compare the WAI measurements of children with DS with those of typically developing, normal-hearing children according to their tympanometric findings.

METHODS

Four groups of children with Down syndrome (age range: 2 years and 4 months to 16 years and 3 months; mean age: 8.5 yr) with normal tympanograms (19 ears), flat tympanograms (13 ears), mild negative pressure tympanograms (6 ears between -100 and -199 daPa at the admittance peak) and severe negative pressure tympanograms (4 ears at -200 daPa or lower at the admittance peak) were assessed. All findings were compared with data obtained from 21 ears of a healthy control group (age range: 3 years and 1 month to 13 years and 11 months; mean age: 7.9 yr). The subjects underwent tympanometry with a 226-Hz probe tone frequency and ER measurements along the 200-6,000 Hz range with a chirp stimulus using the Middle-Ear Power Analyzer (MEPA3 - HearID) by Mimosa Acoustics (Champaign, IL), software, version 3.3 [38].

RESULTS

Statistically significant differences were observed in the ER curves for some comparisons between the studied groups. There was also a negative correlation between the static acoustic admittance at the tympanic membrane level and ER measured with a chirp stimulus at 500 and 1,000 Hz. The discriminant analysis technique, which used a chirp stimulus at 1,000 and 1,600 Hz to classify the participants' data based on ER values, achieved a correct classification rate of 59.52% for participants with DS.

CONCLUSION

While groups with abnormal middle ear status, as indicated by tympanometry, showed higher ER values compared to the DS tymp A group and the control group, similar reflectance curves were observed between control group and the DS tymp A group. WAI shows promise as a clinical diagnostic tool in investigating the impact of middle ear disorders in DS group. However, further research is required to investigate this issue in narrower age range group and a larger sample size.

Down syndrome-A narrative review with a focus on anatomical features

Down syndrome (DS) is the most common aneuploidy of chromosome 21, characterized by the presence of an extra copy of that chromosome (trisomy 21). Children with DS present with an abnormal phenotype, which is attributed to a loss of genetic balance or an excess dose of chromosome 21 genes. In recent years, advances in prenatal screening and diagnostic tests have aided in the early diagnosis and appropriate management of fetuses with DS. A myriad of clinical symptoms resulting from cognitive, physical, and physiological impairments caused by aberrations in various systems of the body occur in DS. However, despite these impairments, which range from trivial to fatal manifestations, the survival rate of individuals with DS has increased dramatically from less than 50% during the mid-1990s to 95% in the early 2000s, with a median life expectancy of 60 years reported recently. The aim of this narrative review is to review and summarize the etiopathology, prenatal screening and diagnostic tests, prognosis, clinical manifestations in various body systems, and comorbidities associated with DS. Clin. Anat. 29:568-577, 2016. © 2015 Wiley Periodicals, Inc.

Threshold changes of ABR results in toddlers and children

INTRODUCTION

Auditory brainstem response (ABR) is a clinically established method to identify the hearing threshold in young children and is regularly performed after hearing screening has failed. Some studies have shown that, after the first diagnosis of hearing impairment in ABR, further development takes place in a spectrum between progression of hearing loss and, surprisingly, hearing improvement.

OBJECTIVE

The aim of this study is to evaluate changes over time of auditory thresholds measured by ABR among young children.

MATERIAL AND METHODS

For this retrospective study, 459 auditory brainstem measurements were performed and analyzed between 2010 and 2014. Hearing loss was detected and assessed according to national guidelines. 104 right ears and 101 left ears of 116 children aged between 0 and 3 years with multiple ABR measurements were included. The auditory threshold was identified using click and/or NB-chirp-stimuli in natural sleep or in general anesthesia. The frequency of differences of at least more than 10dB between the measurements was identified.

RESULTS

In 37 (35%) measurements of right ears and 38 (38%) of left ears there was an improvement of the auditory threshold of more than 10dB; in 27 of those measurements more than 20dB improvement was found. Deterioration was seen in 12% of the right ears and 10% of the left ears. Only half of the children had stable hearing thresholds in repeated measurements. The time between the measurements was on average 5 months (0 to 31 months).

CONCLUSION

Hearing threshold changes are often seen in repeated ABR measurements. Therefore multiple measurements are necessary when ABR yields abnormal. Hearing threshold changes should be taken into account for hearing aid provision.

The prevalence of congenital hearing loss in neonates with Down syndrome

OBJECTIVE

To determine the prevalence of hearing loss in newborns with Down syndrome.

STUDY DESIGN

We performed a cross-sectional, retrospective chart review of all infants with Down syndrome born at a university-affiliated hospital (n = 77) or transferred in to the associated pediatric hospital (n = 32) following birth at an outlying hospital between 1995 and 2010. We determined the rate of failure of newborn hearing screens, the proportion of infants lost to follow-up, and the rate of confirmed hearing loss, as well as the associations of risk factors for hearing loss with confirmed hearing loss.

RESULTS

Of the 109 patients with hearing screening data, 28 failed their newborn hearing screen. Twenty-seven infants were referred for audiologic evaluation, and 19 completed the evaluation. Fifteen of these 19 infants (79%) had confirmed hearing loss. The prevalence of congenital hearing loss in this sample of neonates with Down syndrome was 15%. Exposure to mechanical ventilation was the sole known risk factor associated with hearing loss. In this study, the loss to follow-up rate for infants with positive hearing screens was 32%.

CONCLUSION

Newborns with Down syndrome have a higher prevalence of congenital hearing loss compared with the total neonatal population (15% vs 0.25%). Continued monitoring of hearing is needed in children with Down syndrome.

Assessing cognitive improvement in people with Down syndrome: important considerations for drug-efficacy trials

Experimental research over just the past decade has raised the possibility that learning deficits connected to Down syndrome (DS) might be effectively managed by medication. In the current chapter, we touch on some of the work that paved the way for these advances and discuss the challenges associated with translating them. In particular, we highlight sources of phenotypic variability in the DS population that are likely to impact performance assessments. Throughout, suggestions are made on how to detect meaningful changes in cognitive-adaptive function in people with DS during drug treatment. The importance of within-subjects evaluation is emphasized.

A general review of the otolaryngologic manifestations of Down Syndrome

OBJECTIVE

Down Syndrome (DS) is the most common chromosome abnormality in liveborn children. Otolaryngologists frequently encounter these patients in their practice; in one survey, 50% of DS patients had been seen by Otolaryngology at least once. As such, it is essential that the practicing Otolaryngologist is aware of the otologic, rhinologic, and laryngologic manifestations of this complex disease and comfortable in the management and treatment of these unique patients. Our goal was to provide this information in a concise and definitive document.

METHODS

A comprehensive literature review using PubMed was completed. The terms "Otolaryngology", "Head and neck", "Ear, nose, throat", "Down Syndrome", and "Trisomy 21" were searched in various combinations. Applicable articles that discussed the Otolaryngologic manifestations of Down Syndrome were included.

RESULTS

In total, fifty articles were included for review. The Down Syndrome child tends to have smaller external ear canals, have higher rates of chronic ear disease, and may present with conductive, sensorineural, or mixed hearing loss. As such, DS patients should receive behaviouralaudiological testing every 6 monthsand annually after the age of three in addition to closer follow-up by an Otolaryngologist if tympanic membranes cannot be visualized or if the external auditory canals are significantly stenosed. Management should involve close follow-up and a low threshold for PE tube placement to reduce the risks for speech and language delay. Chronic rhinitis in the Down Syndrome patient is common. Retrognathia, hypotonia, and macroglossia can all cause obstructive sleep apnea (OSA) in this population and therefore each DS patient should get an overnight polysomnograph. Subglottic stenosis, vocal cord paralysis and laryngomalacia are not infrequently seen in the Down Syndrome patient. To reduce acquired subglottic stenosis, endotracheal tubes that are at least two sizes smaller than what is appropriate for the patient's age should be used.

CONCLUSION

Down Syndrome is common and there are many Otolaryngologic manifestations. We recommend that this patient population visit an Otolaryngologist on a regular basis and that the practicing Otolaryngologist is comfortable with the management and treatment of the unique challenges faced with these children.

Hearing level in children with Down syndrome at the age of eight

This study examines the prevalence of hearing loss in children with Down syndrome at the age of 8. All children were examined in the ENT-departments of public hospitals in Norway and the study population consisted of children born in Norway in 2002 with Down syndrome. Hearing loss was defined as pure-tone air-conduction reduction by on average more than 25 dB HL in the best hearing ear. A cross sectional clinical and audiological population based study was chosen as study design. Hearing loss more than 25 dB HL in the best hearing ear was found in 17/49 children (35%). Mild hearing loss was found in 13 children (26%), moderate in 3 (6%) children and severe hearing loss in 1 child (2%). Conductive hearing loss was found in 8 children (16%), 9 children (18%) had a sensory-neural hearing loss, and mixed hearing loss was found in 3 children. Mean hearing level among boys and girls were 30.0 dB HL (SD 15.7) and 25.5 dB HL (SD13.7) respectively, a non-significant difference (p=0.139). In conclusion this study indicates that both conductive and sensorineural hearing loss, is still common in children with Down syndrome children at the age of eight and as much as two thirds of the children may have a bilateral impairment. The study population was under diagnosed in terms of hearing loss and thus our findings underline the importance of continuous audiological follow up of this group of children throughout childhood.

Inner ear anomalies seen on CT images in people with Down syndrome

BACKGROUND

Although dysplasia of inner ear structures in Down syndrome has been reported in several histopathological studies, the imaging findings have not been widely studied.

OBJECTIVE

To evaluate the prevalence and clinical significance of inner ear anomalies detected on CT images in patients with Down syndrome.

MATERIALS AND METHODS

The temporal bone CT images of patients with Down syndrome were assessed for inner ear anomalies; clinical notes and audiograms were reviewed for hearing loss. Logistic regression models were employed to identify which CT findings were associated with sensorineural hearing loss (SNHL).

RESULTS

Inner ear anomalies were observed in 74.5% (38/51) of patients. Malformed bone islands of lateral semicircular canal (LSCC), narrow internal auditory canals (IACs), cochlear nerve canal stenoses, semicircular canal dehiscence (SCCD), and enlarged vestibular aqueducts were detected in 52.5% (53/101), 24.5% (25/102), 21.4% (21/98), 8.8% (9/102) and 2% (2/101) of patients' ears, respectively. IAC stenosis had the highest odds ratio (OR = 5.37, 95% CI: 1.0-28.9, P = 0.05) for SNHL.

CONCLUSION

Inner ear anomalies occurred in 74.5% of our population, with malformed (<3 mm) bone island of LSCC being the most common (52.5%) anomaly. Narrow IAC was seen in 24.5% of patients with Down syndrome and in 57.1% of ears with SNHL. High-resolution CT is a valuable for assessing the cause of hearing loss in people with Down syndrome.

Ten top considerations in pediatric tympanoplasty

Tympanoplasty in children poses some different challenges from the same procedure in adults. The aim of the current article is to review 10 important considerations in pediatric tympanoplasty that focus on these differences and help to optimize the chance of successful outcome.

Identification of Hearing Loss in Pediatric Patients with Down Syndrome

Objective. To determine the type of hearing loss, incidence of the lost to follow-up rate, and the time to diagnose sensorineural hearing loss (SNHL) in children with Down syndrome (DS) identified from a statewide database.

Study Design. Case series with chart review.

Setting. Pediatric referral center.

Subjects and Methods. Three hundred forty-four patients with DS born in Utah between January 2002 and December 2006 were identified using the Utah Department of Health’s Newborn Hearing Screening database and birth defects registry.

Results. Three hundred thirty-two patients were included in the study. Eighty-seven infants (26.2%) did not pass their newborn hearing screening (NBS). Thirty-three of these children (37.9%) had a conductive hearing loss attributed to serous otitis media. Five infants had SNHL; 3 children were diagnosed with a mixed hearing loss (MHL). The average time to diagnose a sensorineural hearing loss was 485 ± 601 days. One child who passed his NBS was subsequently found to have an SNHL. More than 43% of the newborns with DS who passed their NBS developed a conductive hearing loss requiring insertion of ventilation tubes. Eighty-four percent of newborns with DS who did not undergo NBS did not have any apparent subsequent audiologic testing.

Conclusion. Patients with DS present with a relatively high incidence of conductive hearing loss, MHL, and SNHL and a higher lost to follow-up rate compared to patients without DS. The authors were not able to diagnose SNHL within the 90-day period recommended by the Joint Committee on Infant Hearing.

Sensorineural hearing loss: there is no correlation with isolated dysplasia of the lateral semi-circular canal on temporal bone CT

Background

Inner ear malformations may cause sensorineural hearing loss (SNHL). However, the correlation between the small lateral semi-circular canal (LSCC) and SNHL is controversial.

Purpose

To determine whether there is a correlation between the two using CT-based measurement.

Material and Methods

We retrospectively reviewed the high-resolution CT images of the temporal bone obtained from consecutive patients. A total 136 ears of 68 patients (25 men and 43 women; age range 20–85 years, mean 49.8 years) were included in this study. Patients who were clinically suspected to have otosclerosis were also excluded. Two radiologists independently measured the width and cross-sectional area of the bony island of LSCC. We evaluated the correlation between LSCC bone island width or cross-sectional area and hearing level in all cases using Pearson correlation co-efficients. In addition, we compared hearing levels among the patient group with normal-sized LSCC (≧mean-SD), small LSCC (<mean-SD) and very small LSCC (<mean-2SD) as defined by the width and cross-sectional area of the bony island using Student's t-test.

Results

A total 136 ears of 68 patients (25 men and 43 women; age range 20–85 years, mean 49.8 years) were included in this study. No significant correlation was shown between LSCC bony island width or cross-sectional area and hearing level (P > 0.05). No significant difference in hearing levels were found among groups of the normal-sized, small and very small LSCC (P > 0.05).

Conclusion

We conclude that there is no correlation between isolated small LSCC and SNHL.

Peripheral Vestibular System in Down Syndrome

Objective. To evaluate the maturity of the peripheral vestibular system in Down syndrome by examining the number of Scarpa’s ganglion cells and the density of vestibular hair cells.

Study Design. Case-control study using human temporal bones.

Setting. Tertiary academic center, otopathology laboratory.

Subjects and Methods. Sixteen temporal bones from 8 patients with Down syndrome and 15 control temporal bones from 8 individuals with no history of otologic disease were selected. Hypoplasia of the lateral semicircular canal (LSC) and vestibule was investigated by measuring the dimensions of the structures. Scarpa’s ganglion cells were counted under light microscopy. The vestibular hair cells were counted in the LSC crista and the utricular and saccular maculae under differential interference contrast (Nomarski) microscopy and expressed as density.

Results. The patients with Down syndrome were divided into 2 groups: with and without LSC hypoplasia. The number of Scarpa’s ganglion cells and the density of vestibular hair cells were significantly smaller in both groups of patients with Down syndrome than in the control group. There was no significant difference in the number of Scarpa’s ganglion cells or the density of vestibular hair cells between the groups with and without LSC hypoplasia.

Conclusion. The peripheral vestibular system, including Scarpa’s ganglion cells and vestibular hair cells, is hypoplastic irrespective of the vestibular malformation in Down syndrome.

Cognitive deficits and associated neurological complications in individuals with Down's syndrome

Improvements in medical interventions for people with Down's syndrome have led to a substantial increase in their longevity. Diagnosis and treatment of neurological complications are important in maintaining optimal cognitive functioning. The cognitive phenotype in Down's syndrome is characterised by impairments in morphosyntax, verbal short-term memory, and explicit long-term memory. However, visuospatial short-term memory, associative learning, and implicit long-term memory functions are preserved. Seizures are associated with cognitive decline and seem to cause additional decline in cognitive functioning, particularly in people with Down's syndrome and comorbid disorders such as autism. Vision and hearing disorders as well as hypothyroidism can negatively impact cognitive functioning in people with Down's syndrome. Dementia that resembles Alzheimer's disease is common in adults with Down's syndrome. Early-onset dementia in adults with Down's syndrome does not seem to be associated with atherosclerotic complications.

UK and Ireland experience of cochlear implants in children with Down syndrome

OBJECTIVES

Down Syndrome (DS) is associated with a high incidence of hearing loss. The majority of hearing loss is conductive, but between 4 and 20% is sensorineural, which in the main is mild or moderate and is managed with conventional behind-the-ear hearing aids. Cochlear implantation is an elective invasive procedure, performed to provide some form of hearing rehabilitation in individuals with severe to profound sensorineural hearing loss, and initially candidacy criteria were strict--excluding patients with additional disabilities. With good results and expanding experience, more candidates with additional disabilities are now being implanted. A survey of UK and Ireland Cochlear Implant Programmes sought to identify the number of individuals with DS who have been implanted with a cochlear implant (CI) and to provide relevant information on outcomes of implantation in these individuals.

METHODS

E-mail survey of all programmes within the British Cochlear Implant Group (BCIG). Postal questionnaire to programmes identified to have implanted a child with Down Syndrome, with data collection on pre-operative assessment, surgical and post-operative outcomes. Case series review.

RESULTS

Three of 23 BCIG programmes have implanted a child with Down Syndrome. Four children have received implants. No intraoperative or post-operative surgical complications were encountered. All children had middle ear disease, but no problems with implantation were associated with their middle ear condition. All children remain implant users, 12 months to 4 years post-implantation.

CONCLUSION

Cochlear implantation is an option for a child with Down Syndrome and associated severe to profound sensorineural hearing loss. Clinicians caring for these children and their families should consider referral for assessment by a Cochlear Implant Programme.

Otitis media in a mouse model for Down syndrome

The Ts65Dn mouse shares many phenotypic characteristics of human Down syndrome. Here, we report that otitis media, characterized by effusion in the middle ear and hearing loss, was prevalent in Ts65Dn mice. Of the 53 Ts65Dn mice tested, 81.1% had high auditory-evoked brainstem response (ABR) thresholds for at least one of the stimulus frequencies (click, 8 kHz, 16 kHz and 32 kHz), in at least one ear. The ABR thresholds were variable and showed no tendency toward increase with age, from 2 to 7 months of age. Observation of pathology in mice, aged 3-4 months, revealed middle ear effusion in 11 of 15 Ts65Dn mice examined, but only in two of 11 wild-type mice. The effusion in each mouse varied substantially in volume and inflammatory cell content. The middle ear mucosae were generally thickened and goblet cells were distributed with higher density in the epithelium of the middle ear cavity of Ts65Dn mice as compared with those of wild-type controls. Bacteria of pathogenic importance to humans also were identified in the Ts65Dn mice. This is the first report of otitis media in the Ts65Dn mouse as a model characteristic of human Down syndrome.

Genetic syndromes involving hearing

OBJECTIVE

The fundamental processes involved in the mechanism of hearing seem to be controlled by hundreds of genes and hereditary hearing impairment may be caused by a large variety of genetic mutations in different genes. Approximately 150 loci for monogenic syndromic and non-syndromic hearing impairment (HI) disorders have been mapped to the human genome. The identification of these genes and functional analysis of the proteins they encode, are paving the way towards a better understanding of the physiology and pathophysiology of the auditory system. To date, approximately 50 causative genes have been identified.

METHODS

The clinical and neuroradioldical findings of syndromal hearing impairment are analysed.

RESULTS

This paper presents an updated report on genetic syndromes in which a hearing impairment is involved, with a particular attention to the ones associated with external ear and craniofacial malformations.

CONCLUSIONS

Concepts in human genetics are rapidly evolving together with technologies. The concept itself of gene is changing. A genetic diagnosis of syndromal hearing impairment has many practical consequences: it can implies specific prognosis, specific management, specific recurrence risk in relatives and, if the diagnosis is confirmed at the molecular level, possibility of a specific early prenatal diagnosis for severe syndromes. It is important to highlight the necessity that the pediatric otolaryngologist must have a close collaboration with a clinical geneticist and a neuroradiologist.