Clinical value of auditory nerve enhancement in idiopathic sudden sensorineural hearing loss: a retrospective study

The pathogenesis of idiopathic sudden sensorineural hearing loss remains unclear, and no substantial breakthroughs have been achieved in its treatment. Therefore, we conducted this study with the aim to investigate the clinical features and prognostic factors of patients with idiopathic sudden sensorineural hearing loss and auditory nerve enhancement by using three-dimensional fluid-attenuated inversion recovery (3D-FLAIR) magnetic resonance imaging (MRI) of the inner ear.

We retrospectively analyzed the clinical data of adult patients, who experienced sudden unilateral deafness and were admitted to the Department of Otolaryngology, Shandong Provincial ENT Hospital, between December 2020 and July 2021. Patients were divided into an auditory nerve enhancement group and a normal inner ear group, according to 3D-FLAIR MRI findings. Differences in sex, age, side, disease course, underlying diseases, dizziness/vertigo, vestibular function, degree of deafness, hearing classification, and treatment efficacy were analyzed.

Of the 112 cases of sudden idiopathic deafness, 16.07% exhibited enhancement of the auditory nerve on inner-ear 3D-FLAIR MRI. Statistically significant differences in the degree and type of hearing loss were detected between the two groups (p < 0.05). The rates of abnormal results in the caloric, vestibular-evoked myogenic potential, and video head impulse tests were higher in the auditory nerve enhancement group. The cure rate (11.1%) in patients with auditory nerve enhancement was lower than that in patients with normal inner ear MRI findings (28.7%); however, the difference was not statistically significant.

Findings from 3D-FLAIR MRI scans of the inner ear indicated that patients with sudden deafness and auditory nerve enhancement experienced severe hearing loss, aggravated vestibular function injury, and a significantly decreased cure rate. Prompt treatment, ideally within 2 weeks of disease onset, can facilitate hearing recovery.