Objectives Providing hearing compensation to patients with aural atresia is considerably challenging. Hearing aid transducers vibrating the aural cartilage (cartilage conduction; CC) have been devised, and hearing aids utilizing them (CC hearing aids) have quickly become a beneficial option for aural atresia in clinical applications. However, it remains unclear which placement (on the aural cartilage or mastoid) is beneficial to signal transmission. Methods This study included 35 patients (53 ears with an abnormal ear canal and severe conductive hearing loss) who were using CC hearing aids. Thresholds were compared between the transducers on the aural cartilage and on the mastoid. Results In ears with bony aural atresia, thresholds were significantly improved when the transducer was placed on the aural cartilage compared to when it was placed on the mastoid for frequencies ≤ 500 Hz (P < .05). In aural atresia ears with a fibrotic tissue pathway, the aural cartilage stimulation improved the thresholds by approximately 20 dB for frequencies ≤ 1000 Hz (P < .05). In non-atretic ears, the aural cartilage locations significantly worsened the threshold at 4000 Hz (P < .05). Conclusion Our findings demonstrated that placing the transducer at the aural cartilage improved the mid-to-low frequency thresholds compared to mastoid transduction in aural atretic ears. In contrast, no clear improvement to the signal transmission due to the transducer's placement on the aural cartilage was recognized in non-atretic ears. Level of Evidence 2

Background: This study aimed to clarify the prognosis of asymptomatic endolymphatic hydrops (EH) in healthy volunteers via five‐year follow‐ups with inner ear magnetic resonance imaging (MRI).Methods: Inner ear MRI was performed on 115 participants recruited as controls in a previous study on Meniere's disease. The endolymphatic space was visualized using Naganawa's method of contrast‐enhanced MRI with intravenous gadolinium injection and evaluated using Nakashima's method of 2D imaging analysis.Results: Cochlear or vestibular EH was present in 7.0% of participants (n = 8), with all cases being unilateral (laterality), moderate (severity), and asymptomatic (onset). Only cochlear‐localized EH, only vestibular‐localized EH, and both EH were present in 1.7% (n = 2) (C group), 4.3% (n = 5) (V group), and 0.9% (n = 1) (CV group) of participants, respectively. Conducting inner ear MRI after 5 years showed that EH had almost disappeared in two participants in the C and V groups (4/8, 50.0%). EH was still present in three participants in the V group and one in the CV group (4/8, 50.0%). One participant in the V group and another in the CV group presented with residual inner ear EH and developed typical symptomatic Meniere's disease (2/8, 25.0%).Conclusions: Approximately 7% of healthy participants showed asymptomatic EH. Therefore, EH is not the definitive marker for making a diagnosis of Meniere's disease or the suitable predictor for the development of Meniere's disease. Among these participants, 25% maintained EH and subsequently developed typical Meniere's disease within the next 5 years. Schellong‐positive participants maintained persistent EH in the inner ear, and participants with higher scores on the self‐rating depression scale developed Meniere's symptoms after 5 years.Level of evidence: 2a

Various prognostic factors for idiopathic sudden sensorineural hearing loss (SSNHL) have been reported. Hearing loss directly derived from idiopathic SSNHL is important for understanding underlying pathogenesis and outcomes. We assessed the usefulness of evaluating hearing loss and recovery of idiopathic SSNHL on the basis of estimated hearing loss. The study included 115 patients whose characteristics and outcomes of hearing loss were investigated. The effects of vertigo/dizziness and age on hearing thresholds before/after treatment, nonaffected ear threshold, estimated hearing loss, improvement of hearing loss, and estimated remaining hearing loss were investigated. Vertigo/dizziness was a significant prognostic factor for hearing. In vertigo/dizziness patients, significantly more severe hearing loss and poorer improvement of hearing loss were observed above 500 Hz and below 1000 Hz, respectively. Severe hearing disorder remained at all frequencies. Conversely, post-treatment thresholds were significantly higher in the older population (≥65 years), although no differences in pretreatment thresholds were observed between the younger (≤64 years) and older populations. However, on the basis of nonaffected ear thresholds, previously existing hearing loss could have influenced the outcome. Thus, comparison of hearing outcomes between affected and nonaffected ears is essential for understanding hearing loss and outcomes in idiopathic SSNHL cases with existing hearing disorder.