In cochlear disorders, various mechanisms have been identified to promote and inhibit the progression of damage. Herein, we summarize the findings from animal experiments conducted to study cochlear ischemia-reperfusion injury and drug-induced hearing loss. The involvement of reactive oxygen species and glutamic acid in the progression of damage has been confirmed, and neuroexcitotoxicity due to glutamic acid has been observed in cochlear afferent neurons. Damage caused by reactive oxygen species is primarily observed in the hair cells, where reactive oxygen species activate various kinase pathways, leading to caspase activation and apoptosis of the hair cells. Additionally, reactive oxygen species are also known to cause ribbon synapse damage in the inner hair cells, contributing to hidden hearing loss.

　　Lipid mediators have been found to be involved in suppressing the progression of cochlear disorders. Ceramide-1-phosphate (C1P) and sphingosine-1-phosphate (S1P) are generated from sphingomyelin and function as endogenous cell-protective factors. The protective effect of the female hormone estrogen on the cochlea has also been recognized. Thus, in cochlear disorders, both detrimental and protective factors are known to operate within the cochlea, the balance between the two determining the fate of the hair cells.

　　Differences between air-conduction (AC) and bone-conduction (BC) thresholds (air-bone gap) in pure tone audiometry are normally distributed in the range of ±20dB, with a mean value of approximately 0dB in the normal hearing population. A patient with sensorineural hearing loss may also have an air-bone gap, or the opposite air-bone gap, where the BC threshold is worse than the AC threshold. This can affect the diagnosis of both sensorineural and conductive hearing loss. The basic method of masking in pure tone audiometry is the plateau method. Once the principles of the plateau method are understood, the actual procedure can be modified flexibly. However, if the greatest hearing loss is in either ear, the plateau will not appear, making it impossible to obtain separate bone conduction thresholds for the left and right ear.

　　The purpose of this study was to determine whether subjective disability due to unilateral hearing loss (UHL) differed by the degree of hearing loss or the time of onset of hearing loss using the Speech, Spatial and Qualities of Hearing Scale (SSQ). A web-based survey was administered to adults with UHL who are registered with a peer support organization, and 425 responses were obtained. The lowest scores were obtained for spatial hearing, and the respondents were aware of their handicap in certain conversational situations and needed to make an effort to listen to others. Spatial hearing was relatively preserved, while sound clarity and sound quality were more impaired in patients with milder degrees of hearing loss. Acquired onset of hearing loss after adolescence was associated with greater perceived difficulty, suggesting that the difficulty with spatial awareness was not related to the time of onset of hearing loss.

　　This study was aimed at clarifying the understanding of sarcasm in school-aged children with hearing loss. The study was conducted in 18 children with hearing loss and 157 children with normal hearing. The subject children read two types of stories, one story that was characterized by sarcasm story (“sarcasm story”) and one story that was characterized by honesty (“honest story”), and were asked to summarize the speaker's intentions. In both types of stories, the scene or situation and the two main characters' responses to the situation were described, and at the end of the story, the question “How does the speaker really feel?” was posed. In the “sarcasm story,” the main character' statement was positive, despite the negative scene. In the “honest story,” the main character' statement and the emotional content of the scene were matched.

　　Our results showed that when the contextual information was explicitly presented, the children with hearing loss were able to intuitively understand the negative emotion of sarcastic speech just as well as the children with normal hearing could. However, some of the children with hearing loss responded qualitatively differently from those with normal hearing. Further investigation is needed to determine how these qualitative differences might affect the actual understanding of sarcasm by hearing-impaired children.

　　A recent review of medications for tinnitus concluded that there are no drugs available currently that provide long-term benefit in patients with tinnitus. We conducted an observational study to evaluate the effect of clonazepam in addition short-term effect of addition of clonazepam to TRT (tinnitus retraining therapy) on the severity of tinnitus. The subjects were 20 out of 36 patients with tinnitus who visited our hospital between September 2021 and March 2022. The patients were assessed by several questionnaires, including THI (tinnitus handicap inventory), HADS (hospital anxiety and depression scale), and HHIA (Hearing Handicap Inventory for Adult), before and after 4 weeks of administration of clonazepam 0.25mg. The THI score decreased significantly from 49.2±20.4 to 31.4±24.7 (P<0.05). When we set reduction of the THI score by more than 20 or a final score on THI of less than 16 as significant improvement, the rate of improvement was 55% (11/20). We divided the patients into groups depending on the initial score on the THI, as follows: mild group (score <16, N=0); moderate group (score 18 to 56, N=13); and severe group (score >58, N=7). The results revealed a significantly greater rate of improvement in the severe group than in the moderate group (P<0.05). We concluded that addition of clonazepam to TRT is a useful treatment option, especially in severely disabled patients due to tinnitus.

　　Patients with intractable tinnitus often exhibit psychiatric symptoms, such as hopelessness, irritation, anxiety, and depression, which lead to the formation of a vicious cycle that further exacerbates the tinnitus. The directive counseling in Tinnitus Retraining Therapy (TRT) is aimed at reducing these negative emotions, while Cognitive Behavioral Therapy (CBT) is aimed at interrupting the vicious cycle. However, these therapies are time-consuming and difficult to implement in private otolaryngology clinics with limited human and time resources. In this study, we developed a simple four-hour program for training patients on the basic concepts of CBT and the essence of directive counseling in TRT, and conducted group education for eight patients with intractable tinnitus. As a result, the average Tinnitus Handicap Inventory score decreased from 71.0 prior to the group education in the patients to 44.3 following the group education. This study demonstrated that it is possible to support patients with intractable tinnitus by conducting group education based on a simple program, even in a general otolaryngology clinic.

　　In an inclusive setting, 10 children with bilateral sensorineural hearing loss were studied, covering 18 ears due to unilateral evaluations in 2 cases. We aimed attempted to determine the relationship between the speech intelligibility index (SII) values and the intelligibility of Japanese monosyllables and to estimate the amount of Long-Term Average Speech Spectrum (LTASS) amplification that would be effective for improving intelligibility. The mean age of the participants was 9 years 5 months (range, 5-14 years). The mean hearing level of the unaided ear was 65.5±16.1dBHL (range, 41.2-95), and that of the aided ear was 30.7±9.9dBHL. The derived SII value from the International Speech Test Signal (ISTS) serves as a gauge for the adaptability of hearing aid fitting. This importance stems from its, as it has been shown to bear strong correlation with the intelligibility of Japanese monosyllables (rs＝0.79). Furthermore, children with hearing loss require an amplification of 8.5±5.6 dBSPL above the threshold for LTASS to achieve a notable speech intelligibility of 80% or more (p<0.01). Enhancement of speech intelligibility encompasses LTASS amplification across the frequency bands of 250 Hz, 1 kHz, and 4 kHz (F(4, 33) ＝32.5, p<0.01). The SII values and LTASS amplitudes shown in this study offer significant clinical insights into hearing aid fitting in younger children struggling with speech audiometry challenges.

　　With the wide implementation of newborn hearing screening (NHS) in Japan, it has become possible to start intervention for hearing-impaired children from the age of 0. On the other hand, there are still cases in which hearing loss is detected only in late childhood. In order to clarify the current situation and issues up to the start of intervention, we investigated the progress until the start of intervention in children enrolled at our facility during the 8-year period from 2014-2021, and selected cases in which treatment had been started at over 1 year of age for this study. When language delay was observed in infant health checkups, there were many cases in which hearing tests were delayed in the pass group as compared with the non-examination and the non-pass groups. In cases of mild hearing loss without language delay, there were cases in which the family consulted an otorhinolaryngologist regarding hearing problems, but no hearing tests were performed. In the event of any episode leading to suspicion of hearing loss, it is important to conduct hearing tests as soon as possible.