Inner ear

Hearing is essential for communication, and its loss can cause a serious disruption to one's social life. Hearing loss is also recognized as a major risk factor for dementia; therefore, addressing hearing loss is a pressing global issue. Sensorineural hearing loss, the predominant type of hearing loss, is mainly due to damage to the inner ear along with a variety of pathologies including ischemia, noise, trauma, aging, and ototoxic drugs. In addition to genetic factors, oxidative stress has been identified as a common mechanism underlying several cochlear pathologies...

Autoimmune inner ear disease (AIED) is an organ-specific disease characterized by irreversible, prolonged, and progressive hearing and equilibrium dysfunctions. The primary symptoms of AIED include asymmetric sensorineural hearing loss accompanied by vertigo, aural fullness, and tinnitus. AIED is divided into primary and secondary types. Research has been conducted using animal models of rheumatoid arthritis (RA), a cause of secondary AIED. However, current models are insufficient to accurately analyze vestibular function, and the mechanism underlying the onset of AIED has not yet been fully elucidated...

BACKGROUND: There are different ways to analyze energy absorbance (EA) in the human auditory system. In previous research, we developed a complete finite element model (FEM) of the human auditory system. OBJECTIVE: In this current work, the external auditory canal (EAC), middle ear, and inner ear (spiral cochlea, vestibule, and semi-circular canals) were modelled based on human temporal bone histological sections. METHODS: Multiple acoustic, structure, and fluid-coupled analyses were conducted using the FEM to perform harmonic analyses in the 0...

INTRODUCTION: We present a series of six cases whose clinical presentations exhibited audiovestibular manifestations of a third mobile window mechanism, bearing a reasonable resemblance to Ménière's disease and otosclerosis. The occurrence of these cases in such a short period has prompted a review of the underlying causes of its development. Understanding the pathophysiology of third mobile window syndrome and considering these entities in the differential diagnosis of conditions presenting with vertigo and hearing loss with slight air-bone gaps is essential for comprehending this group of pathologies...

Posterior semicircular canal dehiscence (PSCD) has been demonstrated to result in a third mobile window mechanism (TMWM) in the inner ear similar to superior semicircular canal dehiscence (SSCD). Typical clinical and instrumental features of TMWM, including low-frequency conductive hearing loss (CHL), autophony, pulsatile tinnitus, sound/pressure-induced vertigo and enhanced vestibular-evoked myogenic potentials, have been widely described in cases with PSCD. Nevertheless, video-head impulse test (vHIT) results have been poorly investigated...

Adeno-associated virus (AAV)-mediated gene therapy is widely applied to treat numerous hereditary diseases in animal models and humans. The specific expression of AAV-delivered transgenes driven by cell type-specific promoters should further increase the safety of gene therapy. However, current methods for screening cell type-specific promoters are labor-intensive and time-consuming. Herein, we designed a "multiple vectors in one AAV" strategy for promoter construction in vivo. Through this strategy, we truncated a native promoter for Myo15 expression in hair cells (HCs) in the inner ear, from 1,611 bp down to 1,157 bp, and further down to 956 bp...

UNLABELLED: Mechanosensory hair cells located in the inner ear mediate the sensations of hearing and balance. If damaged, mammalian inner ear hair cells are unable to regenerate, resulting in permanent sensory deficits. Aquatic vertebrates like zebrafish (Danio rerio) have a specialized class of mechanosensory hair cells found in the lateral line system, allowing them to sense changes in water current. Unlike mammalian inner ear hair cells, lateral line hair cells can robustly regenerate following damage...

OBJECTIVE: Ear acupuncture, as a system for treating and preventing diseases through stimulation of points on the auricle, has been systematically introduced during the last 60 years. Although the auricular cartography was described somatotopically as an inverted fetus by Paul Nogier, MD, the underlying mechanism of auricular stimulation remains unclear. The aim of this research was to gain an understanding of the structural basis of auricular stimulation, as well as showing the distribution of the nerve fibers, and the blood and lymphatic vessels...

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Inhibitory G alpha (GNAI or Gαi) proteins are critical for the polarized morphogenesis of sensory hair cells and for hearing. The extent and nature of their actual contributions remains unclear, however, as previous studies did not investigate all GNAI proteins and included non-physiological approaches. Pertussis toxin can downregulate functionally redundant GNAI1, GNAI2, GNAI3, and GNAO proteins, but may also induce unrelated defects. Here, we directly and systematically determine the role(s) of each individual GNAI protein in mouse auditory hair cells...

BACKGROUND: The vestibular aqueduct (VA) serves an essential role in homeostasis of the inner ear and pathogenesis of Ménière's disease (MD). The bony VA can be clearly depicted by high-resolution computed tomography (HRCT), whereas the optimal sequences and parameters for magnetic resonance imaging (MRI) are not yet established. We investigated VA characteristics and potential factors influencing MRI-VA visibility in unilateral MD patients. METHODS: One hundred patients with unilateral MD underwent MRI with three-dimensional sampling perfection with application optimized contrasts using different flip angle evolutions (3D-SPACE) sequence and HRCT evaluation...

BACKGROUND: Autoimmune inner ear disease (AIED) manifests with recurrent fluctuating sensorineural hearing loss and vestibular symptoms. Treatment includes steroids and a variety of immunosuppressants. Despite adequate treatment, sensorineural hearing loss can be progressive to the point of deafness. In these patients, a cochlear implant (CI) is indicated. We present the case of a 25-year-old male who underwent cochlear implantation in the left ear. After implantation we noticed brisk variations in impedances which were related to application of the previously prescribed tumor necrosis alpha (TNFα) inhibitor adalimumab...

Spontaneous intracranial hypotension (SIH) is characterized by decreased cerebrospinal fluid (CSF) volume due to leakage through the dural membrane. We present the case of a patient with SIH manifested by fluctuating low-frequency hearing loss, tinnitus, and vertigo. In this patient, endolymphatic hydrops in the cochlea and saccule were visualized by means of a special sequence of inner ear magnetic resonance imaging scans, with a gadolinium-based contrast agent administered intravenously. Endolymphatic hydrops is a potential underlying pathophysiology of SIH-associated hearing impairment...

UNLABELLED: Death of mechanosensory hair cells in the inner ear is a common cause of auditory and vestibular impairment in mammals, which have a limited ability to regrow these cells after damage. In contrast, non-mammalian vertebrates including zebrafish can robustly regenerate hair cells following severe organ damage. The zebrafish inner ear provides an understudied model system for understanding hair cell regeneration in organs that are highly conserved with their mammalian counterparts...

PURPOSE: The definitive treatment for chronic suppurative otitis media is surgery. Surgical technique and procedure varies according to individual case findings and pathology and may require mastoidectomies in which the canal wall is preserved or lowered to eradicate disease from mastoid air cells. Surgical treatment of chronic middle ear disease carries a risk of damage to the inner ear. The aim of this study was to investigate whether the noise produced by the tour system following chronic ear surgery causes sensorineural hearing loss, a condition for which not many studies have been published in the literature...

Vestibular neurectomy is an effective method eliminating vertigo attacks in patients suffering from disabling Meniere's disease with no clinical improvement despite conservative and intratympanic therapy. Magnetic resonance imaging allows in vivo evaluation of changes manifesting in the inner ear after treatment; however, downgrading of the endolymphatic hydrops after vestibular neurectomy had not been previously described in the literature. In the present article, a case of a patient with unilateral severe Meniere's disease treated with selective vestibular nerve section from middle fossa approach was described...

Cellular and molecular alterations associated with hearing loss are now better understood with advances in molecular biology. These changes indicate the participation of distinct damage and stress pathways that are unlikely to be fully addressed by conventional pharmaceutical treatment. Sensorineural hearing loss is a common and debilitating condition for which comprehensive pharmacologic intervention is not available. The complex and diverse molecular pathology that underlies hearing loss currently limits our ability to intervene with small molecules...

Tmc1 and Tmc2 are essential pore-forming subunits of mechanosensory transduction channels localized to the tips of stereovilli in auditory and vestibular hair cells of the inner ear. To investigate expression and function of Tmc1 and Tmc2 in vestibular organs, we used quantitative polymerase chain reaction (qPCR), fluorescence in situ hybridization - hairpin chain reaction (FISH-HCR), immunostaining, FM1-43 uptake and we measured vestibular evoked potentials (VsEPs) and vestibular ocular reflexes (VORs). We found that Tmc1 and Tmc2 showed dynamic developmental changes, differences in regional expression patterns, and overall expression levels which differed between the utricle and saccule...

BACKGROUND: Deaf children with cochlear nerve canal stenosis (CNCs) are always considered poor candidates for cochlear implantation. OBJECTIVES: To investigate the function of the peripheral auditory pathway in deaf children with CNCs, as revealed by the electrically evoked auditory brainstem response (EABR), and postoperative cochlear implants (CIs) outcomes. MATERIALS AND METHODS: Thirteen children with CNCs and 13 children with no inner ear malformations (IEMs) who received CIs were recruited...

PURPOSE: To compare the correlation between different grading methods of vestibular endolymphatic hydrops (EH) and the severity of hearing loss in Ménière's disease (MD), and evaluate the diagnostic value of these methods in diagnosing MD. METHODS: This retrospective study included 30 patients diagnosed with MD from June 2021 to August 2023. All patients underwent inner ear MR gadolinium-enhanced imaging using three-dimensional (3D)-real inversion recovery sequences and pure-tone audiometry...