The incudomalleolar articulation in Down syndrome (trisomy 21): a temporal bone study

Middle Ear Ossicular Joint Changes in Type 2 Diabetes Mellitus: A Histopathological Study

OBJECTIVES

Although previous research has indicated inner ear changes in diabetes mellitus (DM) patients, no prior study has explored the middle ear, particularly the ossicles and their joints, in DM patients. This study aimed to investigate whether type 2 DM is associated with middle ear changes, specifically affecting the ossicular chain and joints.

METHODS

This study included 47 ears from 25 patients with DM (male = 13, female = 12, age: 51.0 ± 20.5) and age- and sex-matched controls (male = 10, female = 10, age: 54.8 ± 15.9) (sex; p = 1.000, Age; p = 0.991). Otopathological evaluations of the auditory ossicles and incudomalleolar joint (IMJ) were performed using light microscopy.

RESULTS

In the IMJ of DM cases, malleus hyalinized cartilage (Malleus hC) and incus hyalinized cartilage (Incus hC) were significantly increased compared with control cases (Malleus hC; DM, 34.17 ± 9.71 μm vs. control 21.96 ± 4.16 μm, p < 0.001) (Incus hC; DM 35.11 ± 10.12 μm vs. control 22.42 ± 4.368 μm, p < 0.001). In addition, bone-line distance was significantly longer than in DM cases than control cases (DM 266.72 ± 59.11 μm vs. control 239.81 ± 35.56 μm p = 0.040). On the other hand, joint discus distance was longer in the control group than in DM cases (DM 96.84 ± 36.80 μm vs. Control 113.63 ± 23.81 μm, p = 0.001).

CONCLUSIONS

This study reveals a notable increase in the hyalinized cartilage layer and bone-line distance accompanied by reducing joint discus distance within the IMJ in DM cases. These findings suggest that DM may influence microjoints, such as the IMJ, and potentially impact auditory function.

EVIDENCE LEVEL

N/A Laryngoscope, 134:2871-2878, 2024.

Ossicular joint histopathology in cases of age-related hearing loss

Objectives

Age-related hearing loss (presbycusis) is a prevalent condition traditionally attributed to inner ear dysfunction. Little is known about age-related changes in the ossicular joints or their contribution to presbycusis. Herein, we performed an otopathologic evaluation of the ossicular joints in cases of presbycusis without a clear sensorineural explanation.

Methods

Histopathologic analysis of the incudomallear (IM) and incudostapedial (IS) joints was performed in specimens from the National Temporal Bone Registry with audiometrically confirmed presbycusis but without histologically observed sensorineural, strial, or mixed features; deemed cases of "indeterminate" presbycusis. Specimens identified as "indeterminate" presbycusis (IP, n = 18) were compared to specimens with histologically confirmed sensorineural presbycusis (n = 16) and strial presbycusis (n = 11). Presbycutic specimens were also compared to age-matched controls (n = 9) and young controls (n = 14).

Results

The synovial space at the center of the IM joint was wider in the IP group (194 ± 36.8 μm) compared to age-matched controls (138 ± 36.5 μm), young controls (149 ± 32.2 μm), and ears with sensorineural presbycusis (148 ± 52.7 μm) (p < .05). The synovial space within the IS joint was wider in the IP group (105 ± 33.0 μm) when compared to age-matched controls (57.9 ± 13.1 μm) and ears with sensorineural presbycusis (62.3 ± 31.2 μm) (p < .05).

Conclusion

IP ears have wider IM and IS joints when compared to ears with sensorineural presbycusis and age-matched controls. Findings point to a potential middle ear source of high frequency conductive hearing loss in a subset of presbycutic ears.

Level of Evidence

Retrospective study.

Human otopathology in scleroderma

Objective

Scleroderma is a complex chronic progressive immune-mediated disease that causes fibrosis of the skin and internal organs, and vasculopathy.Ear involvement has been poorly studied in patients with scleroderma. Vasculitic and autoimmune mechanisms are considered as possible etiologies on hearing impairment, however, this etiology still unclear.Herein, we reviewed three cases of scleroderma from a temporal bone repository.

Methods

The national temporal bone database was reviewed for cases with scleroderma. Clinical case review and correlative otopathologic analysis. Middle and inner ear otopathologic analysis was performed following hematoxylin and eosin staining under light microscopy. Findings were compared to three age-matched controls.

Results

Two patients (three cases) with a history of serologically confirmed scleroderma were identified. Both individuals reported tinnitus and demonstrated bilateral moderate to severe down-sloping sensorineural hearing loss on audiometry. Histologically, the incudomallear joint space was diminished and ossicles appeared demineralized. A loss of hyaline cartilage, and obliteration of the incudomallear and incudostapedial joint synovial spaces was observed. Decreased caliber and intimal hyperplasia of arteries adjacent to ossicles was also identified. Mild diffuse atrophy of stria vascularis in the middle and apical turns of cochlea were found. Hair cell populations were normal. Total spiral ganglion neurons were lower in cases of scleroderma (range 29%-51%) compared to age-matched controls.

Conclusion

Fibrosis, inflammation, and vascular changes were observed in the middle and inner ear in patients with scleroderma. Findings have implications for understanding hearing and vestibular dysfunction in this patient population.

Level of evidence

Retrospective study.

Drug-Targeted Genomes: Mutability of Ion Channels and GPCRs

Mutations of ion channels and G-protein-coupled receptors (GPCRs) are not uncommon and can lead to cardiovascular diseases. Given previously reported multiple factors associated with high mutation rates, we sorted the relative mutability of multiple human genes by (i) proximity to telomeres and/or (ii) high adenine and thymine (A+T) content. We extracted genomic information using the genome data viewer and examined the mutability of 118 ion channel and 143 GPCR genes based on their association with factors (i) and (ii). We then assessed these two factors with 31 genes encoding ion channels or GPCRs that are targeted by the United States Food and Drug Administration (FDA)-approved drugs. Out of the 118 ion channel genes studied, 80 met either factor (i) or (ii), resulting in a 68% match. In contrast, a 78% match was found for the 143 GPCR genes. We also found that the GPCR genes (n = 20) targeted by FDA-approved drugs have a relatively lower mutability than those genes encoding ion channels (n = 11), where targeted genes encoding GPCRs were shorter in length. The result of this study suggests that the use of matching rate analysis on factor-druggable genome is feasible to systematically compare the relative mutability of GPCRs and ion channels. The analysis on chromosomes by two factors identified a unique characteristic of GPCRs, which have a significant relationship between their nucleotide sizes and proximity to telomeres, unlike most genetic loci susceptible to human diseases.

Conductive Hearing Loss with Age-A Histologic and Audiometric Evaluation

A retrospective analysis to quantify age-related changes of the incudo-malleolar joint (IMJ) and incudo-stapedial joint (ISJ), and to analyse changes in the air-bone gap (ABG) with age, was performed. Defined histologic parameters of 153 IMJ and 106 ISJ from subjects aged from birth to 70 years were correlated to age. Additionally, audiograms of 1760 ears of 974 other subjects aged 20 to 80 years were retrospectively analysed and the ABG was correlated to age. The joint space (age group from 0 to 10 compared to 61 to 70 years) became significantly wider with age (IMJ: from a mean of 44 µm to 100 µm, p < 0.001; ISJ: from a mean of 28 µm to 69 µm, p < 0.009. The thickness of cartilage of the incus decreased in the first 20 years of life (IMJ, from a mean of 88 µm to 65 µm, p < 0.01; ISJ: from a mean of 44 µm to 35 µm, p < 0.01). The ABGs of younger ears (20–40 years) was significantly larger at 500 Hz compared to older ears (60–80 years) by 2–4 dB, while it was significantly smaller by 3–5 dB at 4000 Hz (p < 0.0017). Interindividual variations in all age groups were large for both analyses. The increased joint spaces could potentially reduce the stiffness in the joints and explain the increase in ABG at 4000 Hz and the drop at 500 Hz. While the average change is small and of minimal clinical relevance, a larger increase of ABG with age is seen in some subjects.

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.

Histopathology of the Incudomalleolar Joint in Cases of "Indeterminate" Presbycusis

LEVEL OF EVIDENCE

Retrospective study.

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.

Hearing loss in Down Syndrome revisited - 15 years later

OBJECTIVE

In 2001, the senior authors published a study investigating hearing loss in young children (ages 11 months to 3.8 years) with Down Syndrome (DS). We re-visit this same study population to review current audiologic status, the incidence of pressure equalization tube (PET) placement(s), and rate of tympanic membrane (TM) perforations. We aim to better understand the natural history of ear disease and hearing loss in DS and assess potential complications.

METHODS

This retrospective chart review included 57 children with DS who previously completed in 2006, a 5 year, longitudinal study investigating otolaryngologic problems in DS. Updated audiologic data was available for 54. Audiograms, age of ear specific testing, PET placement(s), and tympanic membrane(TM) descriptions were reviewed.

RESULTS

Ages ranged from 14 to 18 years (mean 16.34 years). PET placement occurred in 88.8%, with mean of 3.5 procedures. 30% of PET's were placed after age 6. Ear specific testing was obtained in 92.5% (mean age 4.54 years). Normal hearing was present in 44% (right ear) and 38% (left ear). "Functional" hearing levels, defined as normal or mild hearing loss and speech reception threshold ≤ 30 dB, occurred in 83.3%. Sensorineural/mixed hearing loss was present in 11% (right ear) and 9% (left ear). TM perforations rate was 17%. No cholesteatomas were found.

CONCLUSION

Chronic otitis media and indications for PET's persist as children with DS age. Although functional hearing occurred in 83.3%, there was an overall decrease in hearing levels as the children aged. Tympanic membrane perforations occurred in 17%. Continued surveillance of otologic and audiologic status in patients with Down syndrome is recommended.