The Significant Correlation Between the Density of the Cochlea Otic Capsule and Spine in Hearing Loss Patients

Incidence and risk factors of hearing loss in patients with Turner Syndrome

Background

Hearing loss (HL) is one of the main medical complications for Turner Syndrome (TS) patients, with an earlier presentation and higher incidence than normal women. However, the etiology of HL in TS is unclear. The aim of this study was to investigate the hearing status of TS patients in China and the influencing factors, so as to provide a theoretical basis for early intervention treatment for TS patients with HL.

Methods

In total 46 female patients aged 14–32 diagnosed with TS received tympanic membrane and audiological examinations, including pure tone audiometry and tympanometry. In addition, the effects of karyotype, sex hormone levels, thyroid function, insulin, blood lipids, bone mineral density, age and other factors on hearing levels were analyzed, and the possible risk factors associated with HL in TS patients were explored.

Results

In 9 patients (19.6%) had HL, including 1 (2.2%) with mild conductive hearing loss, 5 (10.9%) with mild sensorineural hearing loss, 3 (6.5%) with moderate sensorineural hearing loss. TS is often associated with age-related mid-frequency and high-frequency HL, and the incidence of HL increases with age. Compared with other karyotypes, patients with 45, X haplotype have an increased risk of mid-frequency HL.

Conclusions

Therefore, karyotype may be a predictor of hearing problems in TS.

Ovariectomized Rat Model and Shape Variation in the Bony Labyrinth

Postmenopausal osteoporosis is a serious concern in aging individuals, but has not been explored for its potential to alter the shape of the inner ear by way of increased remodelling in the otic capsule. The otic capsule, or bony labyrinth, is thought to experience uniquely limited remodelling after development due to high levels of osteoprotegerin. On this basis, despite the widespread remodelling that accompanies osteoporosis, we hypothesize that both the shape and volume of the semicircular canals will resist such changes. To test this hypothesis, we conducted three-dimensional geometric morphometric shape analysis on microcomputed tomographic data collected on the semicircular canals of an ovariectomized (OVX) rat model. A Procrustes ANOVA found no statistically significant differences in shape between surgery and sham groups, and morphological disparity testing likewise found no differences in shape variation. Univariate testing found no differences in semicircular volume between OVX and control groups. The range of variation in the OVX group, however, is greater than in the sham group but this difference does not reach statistical significance, perhaps because of a combination of small effect size and low sample size. This finding suggests that labyrinthine shape remains a tool for assessing phylogeny and function in the fossil record, but that it is possible that osteoporosis may be contributing to intraspecific shape variation in the bony labyrinth. This effect warrants further exploration at a microstructural level with continued focus on variables related to remodelling. This article is protected by copyright. All rights reserved.

Increased cochlear otic capsule thickness and intracortical canal porosity in the oim mouse model of osteogenesis imperfecta

Osteogenesis imperfecta (OI or brittle bone disease) is a group of genetic disorders of the connective tissues caused mainly by mutations in the genes encoding collagen type I. Clinical manifestations of OI include skeletal fragility, bone deformities, and severe functional disabilities, such as hearing loss. Progressive hearing loss, usually beginning in childhood, affects approximately 70% of people with OI with more than half of the cases involving the inner ear. There is no cure for OI nor a treatment to ameliorate its corresponding hearing loss, and very little is known about the properties of OI ears. In this study, we investigate the morphology of the otic capsule and the cochlea in the inner ear of the oim mouse model of OI. High-resolution 3D images of 8-week old oim and WT inner ears were acquired using synchrotron microtomography. Volumetric morphometric measurements were conducted for the otic capsule, its intracortical canal network and osteocyte lacunae, and for the cochlear spiral ducts. Our results show that the morphology of the cochlea is preserved in the oim ears at 8 weeks of age but the otic capsule has a greater cortical thickness and altered intracortical bone porosity, with a larger number and volume density of highly branched canals in the oim otic capsule. These results portray a state of compromised bone quality in the otic capsule of the oim mice that may contribute to their hearing loss.

The Correlation Between Petrous Part of the Temporal Bone Density and the Internal Auditory Canal Diameter in Sensorineural Hearing Loss Patients with Chronic Renal Failure

Patients with chronic renal failure often suffer from hearing loss and the most common cause is sensorineural hearing loss. Sensorineural hearing loss can be caused by cochlear otosclerosis with early symptoms such as decreased petrous part of the temporal bone density due to narrowing of the internal auditory canal. Finding a correlation between the petrous part of the temporal bone density and the anteroposterior diameter of the internal auditory canal in sensorineural hearing loss in patients with chronic renal failure. An observational analytic, cross-sectional study, using a consecutive sampling technique. The petrous part of the temporal bone density decreased in patients with chronic renal failure. The anteroposterior diameter of the internal auditory canal remained normal, there was no association with sensorineural loss. There is a significant correlation between the petrous part of the temporal bone density and sensorineural hearing loss in patients with chronic renal failure. High-resolution CT scans of the mastoid can assist clinicians in determining cochlear otosclerosis and the subsequent detection of the early presence of sensorineural hearing loss.