Cochlear Nerve Atrophy in Postlingual ANSD: Diagnostic Clue and Implications for Cochlear Implantation.

Objective: To evaluate cochlear nerve (CN) atrophy in postlingual auditory neuropathy spectrum disorder (post-ANSD) versus simple sensorineural hearing loss (sSNHL) and its implications for cochlear implantation (CI).

Design: A retrospective study of 61 CI recipients (15 post-ANSD, 46 sSNHL) assessed CN size through imaging, analyzed auditory performance, and compared outcomes based on etiology, age, and molecular subtypes.

Results: Post-ANSD exhibited more severe CN atrophy despite better pure tone averages than sSNHL. Postsynaptic post-ANSD showed significantly greater CN atrophy than presynaptic cases and sSNHL. Although CN atrophy was pronounced, it did not predict poor CI outcomes within the observed thresholds. Speech scores improved markedly post-CI, with no correlation to CN size.

Conclusion: CN atrophy severity is etiology-dependent and most pronounced in postsynaptic post-ANSD. Severe atrophy could serve as a diagnostic marker of postsynaptic post-ANSD without auditory test clues. Early CI is recommended for optimal outcomes, emphasizing timely intervention in post-ANSD patients.