Objectives: We suggest a simple measurement, called the “basal turn–facial ridge (BT–FR) angle,” for determining the electrode insertion axis using preoperative temporal bone computed tomography (CT) to predict hearing preservation (HP) in cochlear implantation (CI). Study Design: Retrospective chart review. Setting: Tertiary referral center. Patients: Eighty-two ears that underwent CI between 2010 and 2018 were included. Ears with preoperative thresholds less than or equal to 80 dB HL at 125, 250, and 500 Hz were enrolled and grouped using the criteria of Skarżyński et al.: Group 1, complete or partial HP; Group 2, minimal HP or complete hearing loss. Intervention: All subjects underwent CI with soft surgery techniques through the round window approach. Main Outcome Measures: The BT–FR angle is the angle between the basal turn line (BT-line), which is a straight line passing through the center of the longitudinal axis of the BT, and the facial ridge line, which is a straight line running from the endpoint of the BT-line to a point just above the facial ridge. Results: The BT–FR angle was 2.5 ± 2.9 degrees in Group 1 and –0.3 ± 2.7 degrees in Group 2 (p = 0.003). The angle and hearing loss showed a significant negative correlation (r = –0.401, p = 0.002). In multiple linear regression, “age at operation” (β coefficient 0.260; p = 0.001) and the “BT–FR angle” (–1.967; p = 0.001) were significant variables affecting the degree of residual hearing loss. Conclusions: The BT–FR angle, which can be measured simply, may be useful to predict residual HP after CI.

Objectives Patients with unilateral hearing loss (UHL) have difficulty in recognizing the direction of a sound. Previous studies have shown that hearing aids (HAs) could improve the directional perception of sound. In this study, we analyzed the results of sound localization tests in patients using a unilateral HA. Methods All patients with UHL who had performed sound localization tests since 2018 were included in this study. Sound localization tests, functional gain tests, and the speech discrimination scores (SDSs) were analyzed. The tests were obtained at 1‐, 3‐, and 6‐month after fitting the HA. Results Of the 32 patients with UHL, 13 were right‐sided and 19 were left‐sided. After 6 months of using a HA, the results of the sound localization test were significantly better in patients with right than left UHL (percent correct [PCT], 61.9 ± 24.0% vs. 37.9 ± 24.6%, p = .011; mean absolute error (MAE), 41.4 ± 23.9° vs. 65.5 ± 28.6°, p = .018; root‐mean‐square error (RMS), 25.8 ± 17.6° vs. 48.8 ± 24.5°, p = .007]. The aided SDSs were not different between the two groups (78.7 ± 16.5% vs. 77.2 ± 18.5%, p = .825). Conclusion The side of the hearing loss could have a substantial effect on sound localization in UHL patients using a HA. Sound localization test results should be interpreted with the consideration of this discordance. Level of Evidence 4

ObjectiveIntracochlear schwannoma is very rare, and complete loss of hearing is inevitable after the removal of this tumor. Here, we discuss cochlear implantation (CI) performed simultaneously with the removal of an intracochlear schwannoma.Study DesignRetrospective single‐center study.SettingTertiary medical institute.MethodsSimultaneous CI and intracochlear schwannoma removal were performed in 4 subjects. After subtotal cochleostomy, the tumors were removed meticulously, with preservation of the modiolus. A new slim modiolar electrode (Nucleus CI632) was placed in a manner that hugged the modiolus. The surgical outcomes of functional gain, word recognition score (WRS), sound localization, and hearing in noise and speech intelligibility tests were investigated.ResultsIntracochlear schwannomas were removed successfully from the 4 patients, with no remnant tumor. The mean aided hearing threshold 6 months after surgery was 25.0 ± 1.8 dB, and the mean‐aided WRS with a 60 dB stimulus was 36.0 ± 18.8% (range 16%‐60%). The Categorical Auditory Performance (CAP) score of the 3 single‐sided deafness patients under contralateral ear masking was 7. The CAP score of the patient with bilateral sensorineural hearing loss was 6, which improved from a preoperative score of 0.ConclusionWhen an intracochlear schwannoma does not completely invade the modiolus, CI with simultaneous tumor removal can be performed successfully, resulting in good hearing performance. A slim modiolar electrode can be placed stably at the modiolus after schwannoma removal.

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Objectives. When performing middle ear operations, such as ossiculoplasty or stapes surgery, patients and surgeons expect an improvement in air conduction (AC) hearing, but generally not in bone conduction (BC). However, BC improvement has often been observed after surgery, and the present study investigated this phenomenon.Methods. We reviewed the preoperative and postoperative surgical outcomes of 583 patients who underwent middle ear surgery. BC improvement was defined as a BC threshold decrease of >15 dB at two or more frequencies. Subjects in group A underwent staged ossiculoplasty after canal wall up mastoidectomy (CWUM), group B underwent staged ossiculoplasty after canal wall down mastoidectomy (CWDM), group C underwent ossiculoplasty only (thus, they had no prior history of CWUM or CWDM), and group D received stapes surgery. We created a hypothetical circuit model to explain this phenomenon.Results. BC improvement was detected in 12.8% of group A, 9.1% of group B, and 8.5% of group C. The improvement was more pronounced in group D (27.0%). A larger gain in AC hearing was weakly correlated with greater BC improvement (Pearson’s r=0.395 in group A, P<0.001; r=0.375 in group B, P<0.001; r=0.296 in group C, P<0.001; r=0.422 in group D, P=0.009). Notably, patients with otosclerosis even experienced postoperative BC improvements as large as 10.0 dB, from a mean value of 30.3 dB (standard error [SE], 3.2) preoperatively to 20.3 dB (SE, 3.2) postoperatively, at 1,000 Hz, as well as an improvement of 9.2 dB at 2,000 Hz, from 37.8 dB (SE, 2.6) to 28.6 dB (SE, 3.1).Conclusion. BC improvement may be explained by a hypothetical circuit model applying the third window theory. Surgeons should keep in mind the possibility of BC improvement when making a management plan.

Objectives When there is a difference in hearing on both ears, where to perform the first cochlear implantation (CI) becomes an important issue. The purpose of the study was to evaluate which ear should be chosen for the first implantation in sequential bilateral CI with a long inter-implant period. Methods The study population consisted of 34 severe-to-profound sensorineural hearing loss pediatrics with the inter-implant period of ≥3 years between the first CI (CI-1) and the second CI (CI-2) before the age of 19 (mean of inter-implant period: 7.1-year). The patients were classified into Group A (CI-1 was performed on the ear with better hearing), Group B (CI-1 on the ear with worse hearing), or Group C (symmetrical hearing in both ears). Speech intelligibility test results were compared between the groups. Results The monosyllabic word scores of CI-1 were excellent in Groups A (91.7±7.9%) and B (92.5±3.6%) but slightly lower in Group C (85.7±14.9%) before the second implantation ( P = .487). At 3 years after the second implantation, all groups demonstrated excellent scores in the bilateral CI condition (95.9±3.0% in Group A; 99.1±.8% in Group B; 97.5±2.9% in Group C, P = .600). However, when the patients were tested in using CI-2 only in Groups A and B after using bilateral CI for 3 years, the scores were inconsistent in Group A (79.6±23.9%; range: 22.2-94.4%), while those were higher and more constant in Group B (92.9±4.8%; 86.8-100.0%). Conclusions The first CI is strongly recommended to perform on a worse hearing ear if they had different hearing levels between ears. Even with the first CI on a worse hearing ear, its performance never deteriorates. In addition, if they receive the second CI several years later, it will be likely that the second one functions better.

Objectives: The objectives of this study were to measure the changes in hearing thresholds in the same individuals during a period of 10 years and suggest a clinical reference for the threshold changes by aging. Methods: In this retrospective cohort study, we used regular health checkup data including 2 pure tone audiometry results with a 10-year interval in the same individuals from 1288 subjects. The subjects’ data including demographics, smoking habits, and the diagnosis of chronic diseases were used. Results: Age, male gender, smoking, and osteoporosis were identified as factors affecting age-related hearing loss (ARHL). The sole effect of aging on ARHL for 10 years according to age groups and genders was as follows: a loss of 1.4 dB in 20s, 4.0 dB in 30s, 5.0 dB in 40s, 8.2 dB in 50s, and 11.2 dB in 60s of males compared to a loss of 2.3 dB in 20s, 2.9 dB in 30s, 5.1 dB in 40s, 6.5 dB in 50s, and 9.4 dB in 60s of females. Conclusions: We could demonstrate the actual effect of aging on ARHL, and it can be used as a clinical reference. Hearing ability decreases more in males than females but seems to decrease exponentially with age in both males and females.

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