Bilateral cochlear-implant users experience interaural frequency mismatch because of asymmetries in array insertion and frequency-to-electrode assignment. To explore the acute perceptual consequences of such mismatch, sentence recognition in quiet was measured in nine bilateral cochlear-implant listeners as frequency allocations in the poorer ear were shifted by 1.5, 3 and 4.5 mm using experimental programs. Shifts in frequency allocation >3 mm were found to reduce bilateral sentence scores below those for the better ear alone, suggesting that the poorer ear interfered with better-ear perception. This was not a result of fewer active channels; deactivating electrodes without frequency shifting had minimal effect.

The authors have declared no competing interest.

This research was supported by the National Institute on Deafness and Other Communication Disorders of the National Institutes of Health under Award Number R01DC015798 (M.J.G., J.G.W.B.).

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The Institutional Review Board at University of Maryland College Park gave ethical approval for this work.

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