Electrode length, placement, and frequency allocation distort place coding for bilateral, bimodal, and single-sided deafened cochlear implant users

Abstract

There is typically a mismatch between the frequency expected at a given cochlear angle and the frequency presented at that angle by a cochlear implant. The frequency mismatch may be particularly important for the population of cochlear implant users who are combining electric hearing across ears or who have electric hearing in one ear and acoustic hearing in the contralateral ear. If the place coding provided by a cochlear implant is misaligned with place coding in the contralateral ear, then the listener may be provided with inconsistent or even conflicting auditory cues. Due to plasticity, the auditory system may be able to compensate for these misalignments. However, data suggest that the ability of some listeners to fully adapt to the distorted or conflicting place maps is limited. The frequency mismatch from a cochlear implant can be adjusted by changing the electrode length, insertion depth, and frequency allocation. Additionally, changing these variables effect the relationship between a change in input frequency and the corresponding change in place pitch.There is typically a mismatch between the frequency expected at a given cochlear angle and the frequency presented at that angle by a cochlear implant. The frequency mismatch may be particularly important for the population of cochlear implant users who are combining electric hearing across ears or who have electric hearing in one ear and acoustic hearing in the contralateral ear. If the place coding provided by a cochlear implant is misaligned with place coding in the contralateral ear, then the listener may be provided with inconsistent or even conflicting auditory cues. Due to plasticity, the auditory system may be able to compensate for these misalignments. However, data suggest that the ability of some listeners to fully adapt to the distorted or conflicting place maps is limited. The frequency mismatch from a cochlear implant can be adjusted by changing the electrode length, insertion depth, and frequency allocation. Additionally, changing these variables effect the relationship between a change in ...