Impact of Frequency Reallocation on Cochlear Implant Outcomes

Conventional cochlear implant (CI) programming applies default frequency allocation without accounting for individual cochlear anatomy. Anatomy-based fitting (ABF) uses cochlear measurements to align frequency allocation with each recipient's tonotopic organization. Objectives: This study compared audiological and subjective outcomes between default fitting and ABF in adult CI users and evaluated the effect of ABF on frequency-to-place mismatch.

Twenty adult CI recipients underwent both default fitting and ABF. Outcomes included pure-tone audiometry, speech discrimination in quiet and noise, and the Abbreviated Profile of Hearing Aid Benefit (APHAB). Frequency-to-place mismatches were calculated for all electrode contacts, and outcomes were statistically compared across fitting strategies.

ABF significantly reduced frequency-to-place mismatch (p < 0.001), with the greatest improvement in the mid-cochlear region. Speech discrimination scores were significantly higher with ABF in quiet and noise (p < 0.001). APHAB scores indicated significantly fewer self-reported hearing difficulties with ABF (p < 0.001). Pure-tone thresholds did not differ between the two fittings.

ABF improves speech perception and subjective hearing outcomes compared with default programming, supporting its clinical value for adults.

ABF offers a simple, software-based approach to improve speech perception and patient-reported outcomes in adult CI users without altering surgical technique.