Measuring Optokinetic Reflex and Vestibulo-Ocular Reflex in Unilateral Vestibular Organ Damage Model of Zebrafish.

One-sided vestibular disorders are common in clinical practice; however, their models have not been fully established. We investigated the effect of unilateral or bilateral deficits in the vestibular organs on the vestibulo-ocular reflex (VOR) and optokinetic reflex (OKR) of zebrafish using in-house equipment. For physical dislodgement of the otoliths in the utricles of zebrafish larvae, one or both utricles were separated from the surrounding tissue using glass capillaries. The video data from VOR and OKR tests with the larvae was collected and processed using digital signal processing techniques such as fast Fourier transform and low-pass filters. The results showed that unilateral and bilateral damage to the vestibular system significantly reduced VOR and OKR. In contrast, no significant difference was observed between unilateral and bilateral damage. This study confirmed that VOR and OKR were significantly reduced in zebrafish with unilateral and bilateral vestibular damage. Follow-up studies on unilateral vestibular disorders can be conducted using this tool.

Analysis of the association between vestibular schwannoma and hearing status using a newly developed radiomics technique.

PURPOSE: Vestibular schwannoma is a benign tumor originating from Schwann cells surrounding the eighth cranial nerve and can cause hearing loss, tinnitus, balance problems, and facial nerve disorders. Because of the slow growth of the tumor, predicting the hearing function of patients with vestibular schwannoma's is important to obtain information that would be useful for deciding the treatment modality. This study aimed to analyze the association between magnetic resonance imaging features and hearing status using a new radiomics technique. METHODS: We retrospectively analyzed 115 magnetic resonance images and hearing results from 73 patients with vestibular schwannoma. A total of 70 radiomics features from each tumor volume were calculated using T1-weighted magnetic resonance imaging. Radiomics features were classified as histogram-based, shape-based, texture-based, and filter-based. The least absolute shrinkage and selection operator method was used to select the radiomics features among the 70 features that best predicted the hearing test. To ensure the stability of the selected features, the least absolute shrinkage and selection operator method was repeated 10 times. Finally, features set five or more times were selected as radiomics signatures. RESULTS: The radiomics signatures selected using the least absolute shrinkage and selection operator method were: minimum, variance, maximum 3D diameter, size zone variance, log skewness, skewness slope, and kurtosis slope. In random forest, the mean performance was 0.66 (0.63-0.77), and the most important feature was Log skewness. CONCLUSIONS: Newly developed radiomics features are associated with hearing status in patients with vestibular schwannoma and could provide information when deciding the treatment modality.

Electrophysiological Changes Associated with the Progression of Noise-Induced Hearing Loss.

BACKGROUND: The aim of this study is to evaluate the clinical characteristics and electrophysiological changes in patients with different degrees of noise-induced hearing loss compared with those of normal controls to elucidate the progression of auditory neural damage attributed to noise exposure. METHODS: A retrospective cohort study was conducted through a review of the medical records for the patients who presented to a tertiary referral center. Sixty-nine participants were included in the study: 29 had noise-induced hearing loss, and 40 were healthy controls. All the participants underwent electrophysiological tests and pure-tone audiometry. RESULTS: Nine patients showed mild hearing loss (mild hearing loss group), while the others showed worse than moderate hearing loss on puretone audiometry (severe hearing loss group). Significantly reduced wave I and V amplitudes of auditory brainstem response were present in both mild and severe hearing loss groups compared to the control group (P -lt; .001 and P=.002, respectively), without significant differences between the mild and severe hearing loss groups. In the multivariate analysis, auditory brainstem response wave V amplitude was negatively associated with auditory brainstem response wave I-V inter-peak latency delay (B=-0.48, P=.02). CONCLUSION: The results of the present study confirm the similarity in the electrophysiological characteristics between the mild and severe hearing loss groups. Thus, widespread disruption in the auditory neural conduction could have been established in the early period when the patient developed mild hearing loss following noise exposure.

Prediction of Hearing Prognosis After Intact Canal Wall Mastoidectomy With Tympanoplasty Using Artificial Intelligence.

OBJECTIVE: To evaluate the performance of a machine learning model and the effects of major prognostic factors on hearing outcomes following intact canal wall (ICW) mastoidectomy with tympanoplasty. STUDY DESIGN: Retrospective cross-sectional study. SETTING: Tertiary hospital. METHODS: A total of 484 patients with chronic otitis media who underwent ICW tympanomastoidectomy between January 2007 and December 2020 were included in this study. Successful hearing outcomes were defined by a postoperative air-bone gap (ABG) of ≤20 dB and preoperative air conduction (AC)-postoperative AC value of ≥15 dB according to the Korean Otological Society guidelines for outcome reporting after chronic otitis media surgery. The light gradient boosting machine (LightGBM) and multilayer perceptron (MLP) models were tested as artificial intelligence models and compared using logistic regression. The main outcome assessed was the successful hearing outcome after surgery, measured using the area under the receiver operating characteristic curve (AUROC). RESULTS: In the analysis using the postoperative ABG criterion, the LightGBM exhibited a significantly higher AUROC compared to those of the baseline model (mean, 0.811). According to the difference between preoperative and postoperative AC, the MLP showed a significantly higher AUROC than those of the baseline model (mean, 0.795). CONCLUSION: This study analyzed multiple factors that could affect the hearing outcome using different artificial intelligence models and found that preoperative hearing status was the most important factor. Our findings provide additional information regarding postoperative hearing for clinicians.

Audiologic results of total ossicular replacement prosthesis bypassing the stapes suprastructure in canal wall down mastoidectomy.

OBJECTIVES: Sometimes performing PORP adequately is challenging when the stapes is tilted or the suprastructure is partially damaged owing to inflammation or infection. In such cases, the implementation of a TORP bypassing the stapes can be a useful alternative. This study aimed to investigate whether bypassing the stapes suprastructure during total ossicular replacement prosthesis (TORP) affects postoperative complications or audiological outcomes. MATERIAL AND METHODS: Among 104 patients who underwent open cavity mastoidectomy and ossiculoplasty using a titanium prosthesis at Korea University Ansan Hospital between January 2012 and December 2019, we compared the preoperative and postoperative audiological results and surgical complications of 52, 21, and 31 patients who underwent partial ossicular replacement prosthesis (PORP), TORP bypassing the remaining stapes suprastructure, and TORP on the stapes footplate or oval window, respectively. RESULTS: The air-bone gap before surgery was significantly different in the TORP on the stapes footplate group (34.2 ± 12.0 dB) than that in the PORP (22.9 ± 13.8 dB) and TORP bypassing the stapes groups (20.7 ± 11.5 dB, p < 0.001). After surgery, there were no significant differences among the groups (p = 0.818). The air-bone gap difference before surgery was associated with the presence of stapes before surgery (p < 0.001). There was no difference in the proportion of postoperative tympanic perforation, whether it was a revision surgery, malleus status, or the size of perforation of the tympanic membrane among the three groups. CONCLUSION: When performing ossiculoplasty using TORP, bypassing the stapes did not affect surgical and audiologic outcomes.

Hydrophilic and lipophilic statin use and risk of hearing loss in hyperlipidemia using a Common Data Model: multicenter cohort study.

Hearing impairment, the third largest health burden worldwide, currently lacks definitive treatments or preventive drugs. This study compared the effects of hydrophilic and lipophilic statin on hearing loss using a common database model. This retrospective multicenter study was conducted in three hospitals in South Korea (Anam, Guro, Ansan). We enrolled patients with hyperlipidemia with an initial hearing loss diagnosis. Data were collected during January 1, 2022-December 31, 2021 using the Observational Health Data Science and Informatics open-source software and Common Data Model database. The primary outcome was the occurrence of first-time hearing loss following a hyperlipidemia diagnosis, as documented in the Common Data Model cohort database. The measures of interest were hearing loss risk between hydrophilic and lipophilic statin use. Variables were compared using propensity score matching, Cox proportional regression, and meta-analysis. Among 37,322 patients with hyperlipidemia, 13,751 (7669 men and 6082 women) and 23,631 (11,390 men and 12,241 women) were treated with hydrophilic and lipophilic statins, respectively. After propensity score matching, according to the Kaplan-Meier curve, hearing loss risk did not significantly differ among the hospitals. The hazard ratio (HR) of the male patients from Anam (0.29, [95% confidence interval (CI), 0.05-1.51]), Guro (HR, 0.56, [95% CI 0.18-1.71]), and Ansan (hazard ratio, 0.29, [95% CI 0.05-1.51]) hospitals were analyzed using Cox proportional regression. Overall effect size (HR, 0.40, [95% CI 0.18-0.91]) was estimated using meta-analysis, which indicated that hearing loss risk among hydrophilic statin users was less than that among lipophilic statin users and was statistically significant. Men in the hydrophilic statin group had a lower risk of hearing impairment than those in the lipophilic statin group.

A Multicenter Cohort Study on the Association between Metformin Use and Hearing Loss in Patients with Type 2 Diabetes Mellitus Using a Common Data Model.

We attempted to explore the association between metformin use and hearing loss in in a large-scale study. This retrospective multicenter cohort study assessed the data of patients with type 2 diabetes mellitus (DM) aged over 40 years using the Observational Health Data Science and Informatics open-source software and the Common Data Model database from 1 January 2002 to 31 December 2019. Each participant was selected using the ICD-10-CM diagnosis code E11 for type 2 DM with sensorineural hearing loss. The participants were divided into metformin and non-metformin users. The outcome measure was the first occurrence of hearing loss after the diagnosis of DM as measured by the CDM cohort study. A total of 80,596 patients, including 46,152 metformin users and 34,444 non-metformin users from three hospitals were assessed. After calibration, we compared the risk of hearing loss using Kaplan-Meier curves, and found significant differences between the groups. The calibrated hazard ratio in the three hospitals (0.79 [95% confidence interval, 0.57-1.12]) was summarized. These findings suggest that the probability of hearing loss-free survival in the metformin user group is higher than that in the non-metformin user group.

Evidence of Cochlear Synaptopathy and the Effect of Systemic Steroid in Acute Idiopathic Tinnitus With Normal Hearing.

OBJECTIVE: To evaluate the electrophysiologic evidence of cochlear synaptopathy and the effects of systemic steroids in acute idiopathic tinnitus with normal hearing. STUDY DESIGN: Retrospective review of medical data. SETTING: Tertiary referral center. PATIENTS: Fifty-nine patients who experienced acute-onset idiopathic tinnitus (within 12 weeks) with normal hearing and the same number of age- and pure-tone threshold-matched control groups. INTERVENTION: Electrophysiologic studies of the auditory pathway, oral steroids, and ginkgo biloba. MAIN OUTCOME MEASURES: Pure-tone thresholds, wave I and wave V amplitudes of the auditory brainstem response (ABR), tinnitus handicap inventory (THI), and visual analog scale (VAS). RESULTS: Significantly reduced ABR wave I amplitude and wave I/wave V ratio were found in the tinnitus group compared with the no tinnitus group. Age and pure-tone threshold were significantly correlated with reduced wave I amplitude and small wave I/wave V ratio. The THI and VAS scores were decreased at 3 and 12 weeks after steroid administration; however, overall changes in THI and VAS scores were not significantly different between the steroid and ginkgo biloba groups. CONCLUSION: Potential cochlear synaptopathy was suspected in the early stage of acute idiopathic tinnitus, even in patients with normal hearing. Age and hearing threshold were potentially associated with the development of cochlear synaptopathy. Low-dose oral steroids and ginkgo biloba induced early subjective relief of tinnitus, which maintained up to 12 weeks, however, those changes did not differ between groups.