The effect of level on bilateral cochlear implant user’s localization accuracy

The effect of level on bilateral cochlear implant user’s localization accuracy

The effect of level on bilateral cochlear implant (CI) user’s localization accuracy

  • Language: Thesis written in English, but preferably German speaker who is willing to communicate with cochlear implant (CI) users in German
  • Suitable as Bachelor or Master Thesis
  • Requirements: MATLAB programming
  • Supervisor: Hongmei Hu

Project: Bilateral cochlear implants (CIs) users rely mostly on interaural level difference (ILD) cues to localize stationary sounds in the horizontal plane. Independent automatic gain control (AGC) in each device can distort this cue, resulting in poorer localization. The fidelity of the preserved ILD cue is level-dependent. For example, ILDs could be faithfully preserved when both signal levels are below the compression threshold. Once the sound level at one of the (or both) CI processors is above the AGC knee-point, the ILDs could be distorted (or reduced symmetrically). In addition, frequency-specific ILD cues might be distorted in the presence of two independent AGC. In some extreme cases, negative ILDs or inverted ILD in the low-frequency channels could be presented. In this case, the sound image might shift in the opposite direction if the listener had only low-frequency electrical hearing available or if these electrodes were perceptually more weighted by the CI users. This thesis is aiming at systematically testing the effect of level on the localization of bilateral CI users with their own speech processors in the free field. If you have any questions or are interested in this project, feel free to write or .

(Changed: 20 Apr 2022)