Objective: To explore the audiological characteristics of infant auditory neuropathy (AN) patients with cochlear microphonic (CM) recorded but no otoacoustic emission (OAE) response and clinically reduce the rate of missed diagnosis of AN. Design: Retrospective clinical study of medical data from 2003 to 2020. Setting: Otolaryngology head and neck surgery clinical hearing center. Participants: Eighteen infant AN patients with CM present and distortion product otoacoustic emission (DPOAE) absent in both ears were OAE absent group. Forty-four infant AN patients with CM and DPOAE present in both ears were OAE present group. Main outcome measures: Audiological characteristics. Results: 1. The age of onset in OAE absent group was 0.9 (0.02) years old, which was less than 1.11 (1.63) years old in OAE present group (P=0.041). 2. The CM threshold of OAE absent group was 80 (10) dB nHL, which was significantly higher (P<0.001) than OAE present group. CM amplitude were smaller (P<0.05), and CM duration were shorter (P<0.05) in OAE absent group. 3. The thresholds of auditory steady-state response (ASSR) at 0.5, 1, 2 and 4 kHz were 94 (10), 94 (10), 87 (20) and 81 (10) dB HL cg respectively in OAE absent group, which were higher than those in OAE present group (P<0.01). Conclusions: Infant AN patients with CM present and OAE absent showed earlier onset, worse hearing level and worse CM performance. The influencing factors and value of CM in AN patients still need to be explored in the future.

Previous studies have shown that patients with acoustic neuroma (AN) sometimes present with sudden sensorineural hearing loss (SSNHL) as an initial symptom. The purpose of this research was to investigate the clinical characteristics, diagnosis and treatment of AN in patients diagnosed as SSNHL initially. A total of 10 patients presented with SSNHL as the initial symptom and diagnosed as AN by magnetic resonance imaging (MRI) finally were enrolled in this study. Patient demographics, associated complaints (mostly tinnitus and vertigo), severity of hearing loss, audiogram configurations, auditory brainstem response (ABR) and MRI examination were reviewed and analyzed. Treatment outcome and management protocols were also included in this study. These patients exhibited varying severity of hearing loss and a variety of audiogram configurations. All patients showed an abnormal ABR. According to the Koos grading standard, there were 5 grade I (intracanalicular) tumors, 3 grade II tumors and 2 grade III tumors. The treatment outcome revealed that 2 patients exhibited recovery of the average hearing of impaired frequency by more than 15 dB, and 6 patients showed no recovery. Four patients were referred to undergo surgical treatment after being diagnosed with AN, 1 patient accepted stereotactic radiation therapy, and the remaining 5 patients were taken “waiting and scan” strategy. The findings of this study show that hearing recovery after corticosteroid treatment for SSNHL does not exclude the presence of AN and all patients diagnosed as SSNHL initially should undergo MRI and ABR to prevent misdiagnosis and delays in potential treatment.