Tonotopic cochlear organization underlies auditory perception, yet cochlear implant (CI) programming typically employs fixed frequency-place maps not based on human physiology. Animal studies suggest intensity-dependent shifts in cochlear tuning, but this has not been confirmed in humans. Here, we demonstrate that cochlear tonotopy dynamically shifts basally with increasing sound intensity in humans. Using intracochlear electrocochleography from a 22-electrode array, we found that high-intensity stimuli (>80 dB SPL) shifted best-frequency locations basally by up to 158° (∼one octave) and significantly broadened cochlear excitation compared to threshold stimulation. This intensity-driven shift challenges static CI frequency mapping and supports a dynamic, intensity-adjusted approach that better replicates natural cochlear processing. Implementing such intensity-based frequency allocation in cochlear implants may reduce place-frequency mismatch, potentially enhancing critical auditory outcomes for CI users, including speech recognition in complex listening environments and improved music perception.

Teaser Higher sound intensity shifts the ear’s internal frequency map, revealing dynamic hearing mechanics in humans.

JAH serves as a consultant for Cochlear Ltd. CAB serves as a consultant for Advanced Bionics, Cochlear Ltd., and IotaMotion, and has equity interests in Advanced Cochlear Diagnostics, LLC.

National Institutes of Health/National Institute on Deafness and Other Communication Disorders institutional training grant T32DC000022 (AW). National Institutes of Health/National Institute on Deafness and Other Communication Disorders grant R01DC020936 (CAB).

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The details of the IRB/oversight body that provided approval or exemption for the research described are given below:

IRB of Washington University in St. Louis gave ethical approval of this work (IRB #202007087).

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