Gap detection ability declines with central auditory neurodegeneration following age-related cochlear synaptopathy.

Age-related hearing impairment (ARHI) is commonly associated with decreased auditory temporal resolution caused by auditory neurodegeneration. Age-related deterioration in gap detection ability, resulting in poor temporal auditory processing, is often attributed to pathophysiological changes in both the peripheral and central auditory systems. This study aimed to investigate whether the gap detection ability declines in the early stages of ageing and to determine its usefulness in detecting peripheral and central auditory degeneration.

Research Application of Laser-induced Shock Wave for Studying Blast-induced Cochlear Injury.

The ear is the organ most susceptible to explosion overpressure, and cochlear injuries frequently occur after blast exposure. Blast exposure can lead to sensorineural hearing loss (SNHL), which is an irreversible hearing loss that negatively affects the quality of life. Detailed blast-induced cochlear pathologies, such as the loss of hair cells, spiral ganglion neurons, cochlear synapses, and disruption of stereocilia, have been previously documented.

Experiences of Percutaneous Endoscopic Approach for the Mastoid Lesions: A Novel Minimally Invasive Ear Surgery.

Objectives: We developed a novel keyhole surgery, named "percutaneous endoscopic ear surgery" (PEES), with the aim of further reducing the invasiveness of otologic surgery. We reported the cases we encountered and retrospectively analyzed the invasiveness of PEES.

Methods: We analyzed the ears of eight patients who underwent PEES for mastoid lesions that could not be manipulated with transcanal endoscopic ear surgery (TEES) at our hospital between July 2021 and November 2022.

Blast-Induced Central Auditory Neurodegeneration Affects Tinnitus Development Regardless of Peripheral Cochlear Damage.

Blast exposure causes serious complications, the most common of which are ear-related symptoms such as hearing loss and tinnitus. The blast shock waves can cause neurodegeneration of the auditory pathway in the brainstem, as well as the cochlea, which is the primary receptor for hearing, leading to blast-induced tinnitus. However, it is still unclear which lesion is more dominant in triggering tinnitus, the peripheral cochlea or the brainstem lesion owing to the complex pathophysiology and the difficulty in objectively measuring tinnitus.

Effects of Unilateral Vagotomy on LPS-Induced Aspiration Pneumonia in Mice.

Respiratory-related dysphagia and aspiration pneumonia can be attributed to multiple causes. However, reproduction of multiple factor-related respiratory distress and aspiration pneumonia in a single animal model is challenging. To validate animals with vagal nerve palsy as novel models for severe aspiration pneumonia associated with respiratory distress, we investigated the effects of unilateral vagotomy on the swallowing function and severity of pneumonia after forced aspiration in mice.

Factors affecting the incidence of chorda tympani nerve transection in middle ear surgery.

Objective: To reveal the factors affecting the incidence of chorda tympani nerve (CTN) transection during middle ear surgery.

Study Design: Retrospective case review.

Setting: Tertiary referral center.

Correlation of Blast-Induced Tympanic Membrane Perforation with Peripheral Cochlear Synaptopathy.

The auditory organs, including the tympanic membrane, cochlea, and central auditory pathway, are the most fragile components of the human body when exposed to blast overpressure. Tympanic membrane perforation (TMP) is the most frequent symptom in blast-exposed patients. The impact of TMP on the inner ear and central auditory system, however, is not fully understood.

Effect of shock wave power spectrum on the inner ear pathophysiology in blast-induced hearing loss.

Blast exposure can induce various types of hearing impairment, including permanent hearing loss, tinnitus, and hyperacusis. Herein, we conducted a detailed investigation of the cochlear pathophysiology in blast-induced hearing loss in mice using two blasts with different characteristics: a low-frequency dominant blast generated by a shock tube and a high-frequency dominant shock wave generated by laser irradiation (laser-induced shock wave). The pattern of sensorineural hearing loss (SNHL) was low-frequency- and high-frequency-dominant in response to the low- and high-frequency blasts, respectively.

Y-27632, a ROCK inhibitor, improved laser-induced shock wave (LISW)-induced cochlear synaptopathy in mice.

Recently, a pathological condition called cochlear synaptopathy has been clarified, and as a disorder of the auditory nerve synapses that occurs prior to failure of hair cells, it has been recognized as a major cause of sensorineural hearing loss. However, cochlear synaptopathy is untreatable. Inhibition of rho-associated coiled-coil containing protein kinase (ROCK), a serine-threonine protein kinase, has been reported to have neuroprotective and regenerative effects on synaptic pathways in the nervous system, including those in the inner ear.

Risk factors of post-tonsillectomy hemorrhage in adults.

Objective: Tonsillectomy is an essential surgery and is conducted on both children and adults. However, the risk factors of post-tonsillectomy hemorrhage for adult patients remain unclear. In this study, we analyzed post-tonsillectomy hemorrhage in adult patients.

Regenerative Effect of a ROCK Inhibitor, Y-27632, on Excitotoxic Trauma in an Organotypic Culture of the Cochlea.

In the past, most inner ear diseases were thought to start with the impairment of the sensory epithelium of the cochlea before subsequently progressing to secondary neural degeneration. However, recent studies show that loss of primary synapses accompanied by excitotoxic degeneration of peripheral axons is likely to be the underlying pathology in sensorineural hearing loss. Rho-associated coiled-coil containing protein kinase (ROCK) inhibition has been reported to have neuroprotective and regenerative effects on synaptic pathways.

Patency of Anterior Epitympanic Space and Surgical Outcomes After Endoscopic Ear Surgery for the Attic Cholesteatoma.

Objective: To reveal the patency of the anterior epitympanic space (AES) and the surgical outcomes after transcanal endoscopic ear surgery (TEES) for attic cholesteatoma with a classification of anatomical variation of the AES.

Study Design: Retrospective case review.

Setting: Tertiary referral center.

Tinnitus rat model generated by laser-induced shock wave; a platform for analyzing the central nervous system after tinnitus generation.

Objective: Tinnitus is a phantom auditory sensation, which is mainly triggered by dysfunction of the peripheral auditory organ, such as cochlear disorders. Additionally, the central nervous system, specifically the limbic system, plays a crucial role in the generation and exacerbation of tinnitus. Therefore, to analyze the hypothesis that tinnitus has strong and specific association with the plastic changes in the limbic system, we assessed the neuronal plastic changes in the limbic system, including the hippocampus and the amygdala, in rats with single-sided tinnitus.

The influence of a noisy environment on hearing impairment and tinnitus: The hearing outcomes of 50-year-old male Japan ground self-defense force personnel.

Objectives: Hearing loss is one of the biggest health problems in the world and occupational noise-induced hearing loss is recognized as the most common work-related illness. However, many factors that result in hearing loss make it difficult to define the specific factor that induces noise-induced hearing loss. To access the exact effect of occupational noise exposure on hearing, we conducted a cross-sectional cohort study of the relationship between noise exposure and hearing impairment in 50-year-old male Japanese Self-Defense Force (JSDF) personnel who work in a noisy environment.

Update on treatment options for blast-induced hearing loss.

Purpose Of Review: The incidence of blast injuries has increased, and the ear is the highest risk organ. Ear injury induced by blast exposure is important in both military and civilian conditions. The permanent hearing loss caused by blast exposure is associated with a decline in the quality of life.

A Case of Gastric Meningeal Carcinomatosis Involving Bilateral Hearing Loss: The Difference between Clinical Images and Autopsy Findings.

We describe a rare case of meningeal carcinomatosis (MC) in a 66-year-old man who presented with bilateral deafness and vertigo, initially presumed to be neurofibromatosis type-2. Brain magnetic resonance imaging (MRI) of the patient revealed bilateral gadolinium enhanced masses at the cerebellopontine angle. However, multiple central nervous system symptoms, including loss of consciousness, gradually appeared.

Blast-induced hearing loss.

The incidence of blast injury has increased recently. As the ear is the organ most sensitive to blast overpressure, the most frequent injuries seen after blast exposure are those affecting the ear. Blast overpressure affecting the ear results in sensorineural hearing loss, which is untreatable and often associated with a decline in the quality of life.

Protein transduction therapy into cochleae via the round window niche in guinea pigs.

Cell-penetrating peptides (CPPs) are short sequences of amino acids that facilitate the penetration of conjugated cargoes across mammalian cell membranes, and as such, they may provide a safe and effective method for drug delivery to the inner ear. Simple polyarginine peptides have been shown to induce significantly higher cell penetration rates among CPPs. Herein, we show that a peptide consisting of nine arginines ("9R") effectively delivered enhanced green fluorescent protein (EGFP) into guinea pig cochleae via the round window niche without causing any deterioration in auditory function.

Recovery of endocochlear potential after severe damage to lateral wall fibrocytes following acute cochlear energy failure.

Reduction of endocochlear potential (EP) is one of the main causes of sensorineural hearing loss. In this study, we investigated changes in the EP using a mouse model of acute cochlear energy failure, which comprised severe cochlear lateral wall damage induced by the local administration of 3-nitropropionic acid to the inner ear. We also analyzed the correlation between EP changes and histological findings in the cochlear lateral wall.

Pathophysiology of the inner ear after blast injury caused by laser-induced shock wave.

The ear is the organ that is most sensitive to blast overpressure, and ear damage is most frequently seen after blast exposure. Blast overpressure to the ear results in sensorineural hearing loss, which is untreatable and is often associated with a decline in the quality of life. In this study, we used a rat model to demonstrate the pathophysiological and structural changes in the inner ear that replicate pure sensorineural hearing loss associated with blast injury using laser-induced shock wave (LISW) without any conductive hearing loss.

Markers of Overall Nutritional Status and Incident Hearing Impairment in Community-Dwelling Older Japanese: The Kurabuchi Study.

Objectives: To examine the association between four markers of overall nutritional status (a serum biomarker (albumin) and three anthropometric indices (body mass index (BMI), midarm circumference (MAC), calf circumference (CC))) and incident hearing impairment in older Japanese adults.

Design: Community-based prospective cohort study.

Setting: Kurabuchi Town, Gunma Prefecture, Japan.

NRF2 Is a Key Target for Prevention of Noise-Induced Hearing Loss by Reducing Oxidative Damage of Cochlea.

Noise-induced hearing loss (NIHL) is one of the most common sensorineural hearing deficits. Recent studies have demonstrated that the pathogenesis of NIHL is closely related to ischemia-reperfusion injury of cochlea, which is caused by blood flow decrease and free radical production due to excessive noise. This suggests that protecting the cochlea from oxidative stress is an effective therapeutic approach for NIHL.

High prevalence of CDH23 mutations in patients with congenital high-frequency sporadic or recessively inherited hearing loss.

Background: Mutations in CDH23 are responsible for Usher syndrome 1D and recessive non-syndromic hearing loss. In this study, we revealed the prevalence of CDH23 mutations among patients with specific clinical characteristics.

Methods: After excluding patients with GJB2 mutations and mitochondrial m.

Low-level laser therapy for prevention of noise-induced hearing loss in rats.

Noninvasive low-level laser therapy (LLLT) is neuroprotective, but the mechanism of this effect is not fully understood. In this study, the use of LLLT as a novel treatment for noise-induced hearing loss (NIHL) is investigated. Sprague-Dawley rats were exposed to intense noise and their right ears were irradiated with an 808nm diode laser at an output power density of 110 or 165mW/cm(2) for a 30min period for 5 consecutive days.

Spontaneous recovery of cochlear fibrocytes after severe degeneration caused by acute energy failure.

Cochlear fibrocytes in the lateral wall region play a critical role in the regulation of inner ear ion and fluid homeostasis, although these are non-sensory cells. Along with other non-sensory cells, fibrocytes in the spiral ligament have been reported to repopulate themselves after damage. However, the studies of regeneration of cochlear fibrocytes have been difficult because a suitable fibrocyte-specific degeneration model did not exist.