Introduction Asymmetric sensorineural hearing loss is the main early symptom of retrocochlear lesions, hence its importance in screening for vestibular schwannomas. Currently, there is no consensus regarding its definition. The objective was to identify the audiometric pattern that would serve as a predictor for vestibular schwannoma in patients with asymmetric hearing loss. Materials and methods A cross-sectional study was conducted that included patients with asymmetric hearing loss attending a secondary care center and a tertiary care center. Clinical, audiometric and imaging (MRI with gadolinium) variables were collected. Asymmetric hearing loss was defined as a difference of 15 dB in one or more frequencies between both ears. The sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV) and accuracy of different audiometric patterns were analyzed. Results A total of 107 patients were studied and divided into two groups: group 1 without vestibular schwannoma (n=98); and group 2 with vestibular schwannoma (n=9). No significant difference in demographic characteristics or audiometric patterns was found in patients with and without vestibular schwannoma. The audiometric pattern with the best sensitivity as a screening test was a difference >20 dB in the 4,000 Hz frequency, with a sensitivity of 77.78%, specificity of 30.61%, PPV of 8.33%, NPV of 93.75% and accuracy of 34.50%. Conclusion The audiometric pattern with the best results was a difference >20 dB in the 4,000 Hz frequency range; however, patients with asymmetric hearing loss could not be differentiated from patients with retrocochlear lesions based only on audiometry. Asymmetrical hearing loss must be studied with MRI.

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Objective: To evaluate the efficacy of on demand and low dose intratympanic gentamicin (ITG) in patients with intractable Meniere's disease (MD). Study Design: Clinical chart review. Setting: Secondary care center. Patients: Subjects with MD who failed conventional treatment and underwent on demand ITG infiltration from June 2013 to December 2018. Intervention: 0.4 to 0.5 ml of buffered gentamicin were administered through an intratympanic route. A total of 5 mg in case of low dose and 20 mg as a standard dose. Main Outcome Measures: Vertigo control, Meniere's Disease Functional Level Scale (MDFLS), Dizziness Handicap Inventory (DHI), and pure tone audiometry pre and posttreatment. Results: Thirty-one patients, 16 women and 15 men with a mean age of 52.81 (22–79) years were included. The number of ITG injections ranged from 1 to 7, with a mean of 2.52 applications per patient. Mean interval between doses was 212.15 (21–1442) days. Average follow-up was 24.03 months. An improvement on MDFLS was seen on 77.4% (n = 24) patients. DHI score improved after gentamicin treatment (mean 55.23 versus 24.06, p ≤ 0.001). Thirty patients (96.8%) reached complete or substantial vertigo control. Only one patient did not achieve control. Hearing was preserved in 43.5% (n = 10) of analyzed audiograms, whereas 17.4% (n = 4) developed hearing loss greater than 20 dB, which was not statistically significant (p = 0.099). Conclusions: In our study, on demand and low dose ITG was effective for vertigo control in patients with intractable MD. Individualized therapy is recommended in all patients to minimize vestibular and cochlear toxicity.

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