[Clinical characteristics of acoustic neuroma patients with normal hearing]

Objective:To analyze the clinical characteristics of unilateral acoustic neuroma（AN） with normal hearing, so as to provide evidence for early identification AN. Methods:Clinical datas from 73 patients of unilateral AN with normal hearing of Otorhinolaryngology Head and Neck Surgery of Beijing Tiantan Hospital affiliated of Capital Medical University from August 2019 to April 2022 admitted to department were retrospectively analyzed. All patients underwent pure tone audiometry（PTA）, speech discrimination score（SDS）, auditory brainstem response（ABR）, distortion product otoacoustic emission（DPOAE） and head enhanced MRI. Results:The incidence of normal hearing among patients with AN was 10.7%. Male∶female=1∶2.2; the mean age of the patients was（37.3±9.4） years; the mean tumor size was（24.2±11.2） mm. Tinnitus was the most common reason for visit; the patients who had headache and dizziness had larger tumors. Surgery was the main treatment, and the patients who underwent surgery had larger tumors than those of follow-up. Heterogeneous tumors were the most common type of MRI, homogeneous tumors were smaller than heterogeneous and cystic tumors. The sensitivity of ABR in the diagnosis of AN with normal hearing was 95.9%, and that of ≥20 mm tumors was 100%; prolonged Ⅴ-waves were the most common, patients with Ⅴ-wave deletion had larger tumors than those with normal or prolonged Ⅴ-waves. Patients who had the longer the Ⅴ-wave and the longer difference between Ⅰ-Ⅴ wave had larger tumors. DPOAE was not elicited at full frequency in 11 patients. There was no statistically significant difference in age among patients with different symptoms, treatments, types of MRI, ABR and DPOAE. Conclusion:AN of normal hearing was most common in 30-39 years old women. Patients had different symptoms, phenotypes of MRI and ABR. Patients with normal hearing who had tinnitus, dizziness, headache, facial paraesthesia, and recovery after sudden haring loss can be further examination of ABR and DPOAE for early identification AN. The sensitivity of ABR in diagnosis of hearing normal AN was 95.9%, and the abnormal type of Ⅴ-wave is related to tumor size.