Asymmetry in Cortical Thickness of the Heschl's Gyrus in Unilateral Ear Canal Atresia.

HYPOTHESIS: Unilateral congenital conductive hearing impairment in ear canal atresia leads to atrophy of the gray matter of the contralateral primary auditory cortex or changes in asymmetry pattern if left untreated in childhood. BACKGROUND: Unilateral ear canal atresia with associated severe conductive hearing loss results in deteriorated sound localization and difficulties in understanding of speech in a noisy environment. Cortical atrophy in the Heschl's gyrus has been reported in acquired sensorineural hearing loss but has not been studied in unilateral conductive hearing loss. METHODS: We obtained T1w and T2w FLAIR MRI data from 17 subjects with unilateral congenital ear canal atresia and 17 matched controls. Gray matter volume and thickness were measured in the Heschl's gyrus using Freesurfer. RESULTS: In unilateral congenital ear canal atresia, Heschl's gyrus exhibited cortical thickness asymmetry (right thicker than left, corrected p = 0.0012, mean difference 0.25 mm), while controls had symmetric findings. Gray matter volume and total thickness did not differ from controls with normal hearing. CONCLUSION: We observed cortical thickness asymmetry in congenital unilateral ear canal atresia but no evidence of contralateral cortex atrophy. Further research is needed to understand the implications of this asymmetry on central auditory processing deficits.

Concomitant Dehiscences of the Temporal Bone: A Case-Based Study.

Otic capsule dehiscences create a pathological third window in the inner ear that results in a dissipation of the acoustic energy consequent to the lowered impedance. Superior semicircular canal dehiscence (SSCD) was identified by Minor et al in 1998 as a syndrome leading to vertigo and inner ear conductive hearing loss. The authors also reported the relation between the dehiscence and pressure- or sound-induced vertigo (Tullio's phenomenon). Prevalence rates of SSCD in anatomical studies range from 0.4% to 0.7% with a majority of patients being asymptomatic. The observed association with other temporal bone dehiscences, as well as the propensity toward a bilateral or contralateral "near dehiscence," raises the question of whether a specific local bone demineralization or systemic mechanisms could be considered. The present report regard a case of a patient with a previous episode of meningitis, with a concomitant bilateral SSCD and tegmen tympani dehiscence from the side of meningitis. The patient was affected by dizziness, left moderate conductive hearing loss, and pressure/sound-induced vertigo. Because of disabling vestibular symptoms, the patient underwent surgical treatment. A middle cranial fossa approach allowed to reach both dehiscences on the symptomatic side, where bone wax and fascia were used for repair. At 6 months from the procedure, hearing was preserved, and the vestibular symptoms disappeared.

Effects of location, size and shape of tympanic membrane perforations on hearing: analysis of 400 cases.

OBJECTIVE: This study aimed to evaluate the effect of size, location and shape of tympanic membrane perforations on hearing levels of a large study group treated in a tertiary referral centre. METHOD: Medical data of 458 patients with tympanic membrane perforations were evaluated. RESULTS: A total of 336 patients had normal middle-ear findings during the surgical procedures. There was a significant difference in terms of mean pure tone average and air-bone gap values between posterior-inferior and anterior-inferior perforations (p = 0.005 and p = 0.044, respectively). The mean air-bone gap value of kidney-shaped perforations was significantly higher. Posterior-superior and posterior perforations were significant indicators for ossicular chain defects (p < 0.001; odds ratio, 14.2 and p = 0.004; odds ratio, 3.4, respectively). CONCLUSION: Perforations located in the posterior-inferior quadrant caused the greatest hearing loss. The difference between posterior-inferior and anterior-superior or inferior perforations was statistically significant. Posterior perforations had a significant relationship with ossicular chain pathologies. Kidney-shaped perforations caused higher pure tone average and air-bone gap values than annular, elliptical or pinpoint perforations.

Decreasing auditory input induces neurogenesis impairment in the hippocampus.

Hearing loss is associated with cognitive decline and dementia risk. Sensorineural hearing loss suppresses hippocampal neurogenesis, resulting in cognitive decline. However, the underlying mechanism of impaired neurogenesis and the role of microglial activation and stress responses related to hearing loss in the hippocampus remains unknown. Using a conductive hearing loss (CHL) model, we investigated whether a decrease in sound level could induce impairment of hippocampal neurogenesis and examined the differences between unilateral CHL (uCHL) and bilateral CHL (bCHL). To establish the CHL mouse model, ears were unilaterally or bilaterally occluded for five weeks by auditory canal ligation. Although hearing thresholds were significantly increased following CHL, CHL mice exhibited no significant loss of spiral ganglion or hippocampal neurons. Hippocampal neurogenesis was significantly and equally decreased in both sides following uCHL. More severe decreases in hippocampal neurogenesis were observed in both sides in bCHL mice compared with that in uCHL mice. Furthermore, microglial invasion significantly increased following CHL. Serum cortisol levels, which indicate stress response, significantly increased following bCHL. Therefore, auditory deprivation could lead to increased microglial invasion and stress responses and might be a risk factor for hippocampal neurogenesis impairment.

Effects of tympanic membrane perforation, middle ear cavity volume, and mastoid aeration on hearing impairment.

AIMS: To investigate the effects of the location and size of tympanic membrane (TM) perforation and middle ear cavity volume on conductive hearing loss in patients with TM perforation. METHODS: Data were collected via a retrospective medical chart review. RESULTS: We enrolled 128 patients with a mean age of 45.6 ± 10.1 years. The mean perforation size was 21.2 ± 8.6% of the TM area, and the mean air-bone gap (ABG) was 20.2 ± 8.6 dB HL on pure tone audiometry. Patients were divided into two groups based on mean ABG. Patients with a large ABG had a significantly larger TM perforation area and smaller mastoid volume. The TM perforation was most commonly located in the central section. However, regression analyses showed that the proportion of the perforated TM area was the only independent predictor of a large ABG (odds ratio, 1.053; 95% confidence interval, 1.022-1.085; p = 0.001). When we analyzed the frequencies in which hearing loss occurred due to TM perforation, we confirmed that hearing loss occurred mainly in the low-frequency range. CONCLUSION: In patients with TM perforation, conductive hearing loss occurs mainly at low frequencies and in proportion to the size of the TM perforation.

Double Ring in Cochlear Otosclerosis: A Limit to Cochlear Implantation? The Solution Is the Surgical Approach.

We present a case of a 50-year patient with a severe form of otosclerosis (double ring) that was successfully implanted. We used a bone-anchored hearing implant for restoring the hearing in the right side and a cochlear implant in the left side; both surgeries did not show any complications. For reducing the risk of a secondary bone ossification related to the trauma of cochleostomy for electrode's insertion, we used a round window approach. The patient recovered a normal auditory threshold and normal speech perception capacity both in silence and noise conditions 1 year after surgery.

Right Incus Osteoma in a Child: A Differential Diagnosis of Middle Ear Malformations.

Osteomas of the temporal bone, especially those involving the incus, are rare, unilateral, benign osseous tumors. The clinical presentation is usually isolated conductive hearing loss, and the diagnosis is confirmed by a temporal computed tomography scan. Osteomas of the incus represent a differential diagnosis of congenital middle ear malformations in children, which are the most frequent cause of conductive hearing loss with a normal eardrum in the pediatric population. In case of disabling symptomatology, surgery seems to be a safe way to recover normal hearing.

Activity-Dependent Neurodegeneration and Neuroplasticity of Auditory Neurons Following Conductive Hearing Loss in Adult Mice.

We examined the functional and structural changes of auditory neurons (ANs) in adult mice after conductive hearing loss (CHL). Earplugs (EPs) were bilaterally inserted in male 8-week-old mice for 4 weeks [EP(+) group] and subsequently removed for 4 weeks [EP(+/-) group]. We examined the control mice [EP(-) group] with no EPs inserted at 12 weeks. The auditory brainstem response (ABR) was measured to determine the cochlear function before and after EP insertion, after EP removal, and at 4 weeks following EP removal. We examined the cochleae for hair cell (HC) and spiral ganglion neuron survival, synaptic and neural properties, and AN myelination. There was a significant elevation of the ABR threshold across all tested frequencies after EP insertion. After removing the occlusion, these threshold shifts were fully recovered. Compared with the EP(-) mice, the EP(+) mice showed a significant decrease in the ABR peak 1 amplitude and a significantly prolonged latency at all tested frequencies. There was no significant effect of auditory deprivation on the survival of HCs and ANs. Conversely, auditory deprivation caused significant damage to the synapses and myelin and a significant decrease in the AN size. Although functional changes in the ABR amplitude and latency did not fully recover in the EP(+/-) mice, almost all anatomical changes were fully recovered in the EP(+/-) mice; however, cochlear synapses only showed partial recovery. These results suggest that auditory activities are required to maintain peripheral auditory synapses and myelination in adults. The auditory deprivation model allows for assessment of the mechanisms of synaptopathy and demyelination in the auditory periphery, and synaptic and myelin regeneration in sensorineural hearing loss.

Optimizing Management of Otophyma: A Case Series Highlighting the Role of Surgical and Retinoid Therapy.

Otophyma is a rare condition that can result in conductive hearing loss. Current otophyma literature does not examine validated treatment outcomes for patients. Utilizing a medical and surgical approach to maintain a patent canal can lead to significant objective improvements. The aim of this case series is to describe a combined successful approach in 3 cases from an academic, multidisciplinary center. The main outcomes analyzed were pre and post air-bone gap audiogram analysis and disimpaction frequency. The results showed that post-management, patient 1 had substantial improvement in hearing, recovering 49 dB in his right ear and 25 dB in his left ear, demonstrating near complete air-bone gap closure. Patient 2 showed a similar dermatologic and functional improvement, although objective audiometric assessment related to otophyma could not be performed due to coexisting chronic otitis media and cholesteatoma. Patient 3, in the 12 months prior to comanagement, had 8 bilateral disimpactions, and following comanagement had 2 disimpactions in 23 months. All 3 patients were pleased with the resultant functional and physical appearance following comanagement. By presenting this approach and objective measures of treatment, we hope to improve future clinical decision-making in a rare condition.

A Case Series of X-Linked Deafness-2 with Sensorineural Hearing Loss, Stapes Fixation, and Perilymphatic Gusher: MR Imaging and Clinical Features of Hypothalamic Malformations.

X-linked deafness-2 (DFNX2) is an X-linked recessive disorder characterized by profound sensorineural hearing loss and a pathognomonic temporal bone deformity. Because hypothalamic malformations associated with DFNX2 have been rarely described, we aimed to further describe these lesions and compare them with features of a nonaffected population. All patients diagnosed with DFNX2 between 2006 and 2019 were included and compared with age-matched patients with normal MR imaging findings and without hypothalamic dysfunction. MR imaging features differing between groups were selected to help identify DFNX2. Sensitivity and specificity were calculated for these features. Agreement among 3 radiologists was quantified using the index κ. Information on the presence or absence of gelastic seizures, precocious puberty, or delayed puberty was also gathered. We selected distinctive MR imaging features of hypothalamic malformations in DFNX2. The feature selected on axial T2 images was the folded appearance of the ventromedial hypothalamus (sensitivity, 100%; specificity, 95.8%) characterized by an abnormal internal/external cleft (sensitivity, 100%; specificity, 95.7%). On coronal T2, the first distinctive feature was a concave morphology of the medial eminence (sensitivity, 100%; specificity, 97.1%), the second feature was at least 1 hypothalamic-septum angle ≥90° (sensitivity, 90%; specificity, 72.5%), and the third feature was a forebrain-hypothalamic craniocaudal length of ≥6 mm (sensitivity, 70%; specificity, 79.7%). Clinical features were also distinctive because 9 patients with DFNX2 did not present with gelastic seizures or precocious puberty. One patient had delayed puberty. The κ index and intraclass correlation coefficient ranged between 0.78 and 0.95. Imaging and clinical features of the hypothalamus suggest that there is a hypothalamic malformation associated with DFNX2. Early assessment for pubertal delay is proposed.

Inner-Ear Disorders Presenting with Air-Bone Gaps: A Review.

Air-bone gaps (ABGs) are commonly found in patients with conductive or mixed hearing loss generally due to outer- and/or middle-ear diseases such as otitis externa, tympanic membrane perforation, interruption or fixation of the ossicular chain, and chronic suppurative otitis media. ABGs can also be found in correlation with inner-ear disorders, such as endolymphatic hydrops, enlarged vestibular aqueduct syndrome, semicircular canal dehiscence, gusher syndrome, cochlear dehiscence, and Paget disease's as well cerebral vascular anomalies including dural arteriovenous fistula. The typical clinical presentation of inner-ear conditions or cerebral vascular anomalies causing ABGs includes audiological and vestibular symptoms like vertigo, oscillopsia, dizziness, imbalance, spinning sensation, pulsatile or continuous tinnitus, hyperacusis, autophony, auricular fullness, Tullio's phenomenon, and Hennebert's sign. Establishing a definitive diagnosis of the underlying condition in patients presenting with an ABG is often challenging to do and, in many patients, the condition may remain undefined. Results from an accurate clinical, audiological, and vestibular evaluation can be suggestive for the underlying condition; however, radiological assessment by computed tomography and/or magnetic resonance imaging is mandatory to confirm any diagnostic suspicion. In this review, we describe and discuss the most recent updates available regarding the clinical presentation and diagnostic workup of inner-ear conditions that may present together with ABGs.

New Imaging Findings of Incomplete Partition Type III Inner Ear Malformation and Literature Review.

Incomplete partition type III, also referred to as X-linked deafness, is a rare genetic inner ear malformation. Its characteristic CT findings, including bulbous dilation of the internal auditory canal and absence of the modiolus with the interscalar septa present, have been well-recognized. In this series of 19 cases, we report the abnormalities of the vestibule and semicircular canals and provide a comprehensive description of their CT and MR imaging findings. The inner ear malformations in incomplete partition type III were bilateral and basically symmetric, with involvement of the internal auditory canal, nerve canals in the fundus, cochlea, vestibule, semicircular canals, vestibular aqueduct, otic capsule, round window, oval window, and stapes. An irregular vestibule with a cystic appearance is also a distinctive imaging feature, which could be seen in about 90% of our patients, with a cystic appearance of the semicircular canals present in nearly half of the cases.

Multiple synostoses syndrome: Clinical report and retrospective analysis.

Multiple synostoses syndrome (SYNS1; OMIM# 186500) is a rare autosomal dominant disorder reported in a few cases worldwide. We report a Chinese pedigree characterized by proximal symphalangism, conductive hearing loss, and distinctive facies. We examined the genetic cause and reviewed the literature to discuss the pathogeny, treatment, and prevention of SYNS1. Audiological, ophthalmological, and radiological examinations were evaluated. Whole-exome sequencing (WES) was performed to identify mutations in the proband and her parents. Sanger sequencing was used to verify the results for the proband, parents, and grandmother. The literature on the genotype-phenotype correlation was reviewed. The patient was diagnosed with multiple synostoses syndrome clinically. WES and bioinformatic analysis revealed a novel missense mutation in the NOG gene, c.554C>G (p.Ser185Cys), cosegregated in this family. The literature review showed that the phenotype varies widely, but the typical facies, conductive hearing loss, and proximal symphalangism occurred frequently. All reported mutations are highly conserved in mammals based on conservation analysis, and there are regional hot spots for these mutations. However, no distinct genotype-phenotype correlations have been identified for mutations in NOG in different races. Regular systematic examinations and hearing aids are beneficial for this syndrome. However, the outcomes of otomicrosurgery are not encouraging owing to the regrowth of bone. This study expanded the mutation spectrum of NOG and is the first report of SYNS1 in a Chinese family. Genetic testing is recommended as part of the diagnosis of syndromic deafness. A clinical genetic evaluation is essential to guide prevention, such as preimplantation genetic diagnosis.

Tophaceous Gout of the Middle Ear: Case Reports and Review of the Literature.

Tophaceous gout of the middle ear is a rare occurrence that presents as a granular white-colored mass. It is frequently misdiagnosed as cholesteatoma or tympanosclerosis in patients who otherwise may not manifest any clinical or biochemical signs of gout. While uncommon, it can lead to clinically significant disease such as conductive hearing loss. The present report describes 2 cases of middle ear gouty tophi initially mistaken for another entity. Both patients underwent surgery, and the diagnosis of gout was revealed after final histopathological analysis. A review of the literature is also presented.

Audiometric Results of Stapedotomy Surgery for Otoscelorsis: Influence of the Radiological Stage.

BACKGROUND: The objective of this study was to identify a correlation between the radiological stage of otosclerosis and the pre- and postoperative audiometric results of patients who underwent a stapedotomy. METHODS: Ninety-three patients with radiologically and surgically confirmed otosclerosis who underwent stapedotomy surgery and CT scanning within 18 months before the operation were included. The CT scans were interpreted by an otologist and a specialised radiologist to determine their radiological stage according to the classification of Veillon and Fraysse. The patients received a pre- and postoperative audiogram in the short and long term. RESULTS: The preoperative bone conduction thresholds were higher in patients who presented with an advanced radiological stage of otosclerosis: 32.7 dB ±â€Š12.4 compared with those who presented with a less advanced radiological stage: 24.3 dB ±â€Š10.0. The preoperative air conduction thresholds were higher in patients who presented with an impairment of the round window: 58.1 dB ±â€Š13.5 compared with those who presented with no impairment of the round window: 48.7 dB ±â€Š14.5. The postoperative improvement in the air-bone gap was significantly higher for the localised foci: 16.9 dB ±â€Š8.6 versus 11.0 dB ±â€Š9.2, but only in the short term. CONCLUSION: There was a clinical radiological correlation with the preoperative results: In BC, there was a correlation with the radiological stage of Veillon and in AC, there was a correlation with impairment of the round window. The link between the radiological stage of otosclerosis and the postoperative audiometric results is less obvious. In the short term, the audiometric improvements in the air-bone gap were greater in patients in the early stages according to the Veillon classification, but this result was not sustained in the long-term.

Bilateral auditory ossicular expansions in a child with beta-thalassemia major: Case report and literature review.

Marrow proliferation of the ossicular chain is a rare phenomenon. To date, only two other cases have described this rarity. We report a third paediatric case from Australia. A seven-year-old with thalassemia major demonstrated conductive impairment during surveillance for Deferasirox ototoxicity. Otitis media was assumed, however, CT scan of the petrous temporal bone revealed extramedullary haematopoiesis causing bilateral ossicular expansions and fixed conductive deficit. Reports of hearing loss in the thalassemia population focus on sensorineural impairment from iron chelation therapies. Clinicians should suspect ossicular deformation where treatment has been delayed, poorly controlled or conductive deficit persists without effusion.