Listening through a Cochlear Implant

Authors: Jesko L. Verhey


A cochlear implant (CI) partially restores hearing for profoundly deaf patients. It is a surgical implanted electronic device. It includes an array of electrodes that are inserted into the inner ear. These electrodes stimulate the auditory nerve by short electric pulses. To transmit spectral information of the sound it uses the concept of frequency-place transformation, which is observed in the healthy cochlea. Thus, a key part of the signal processing is a filterbank analysis. Due to the filterbank processing and a subsequent envelope extraction, the sound processing of a CI severely affects sound information. This talk will focus on two aspects of sound perception through a CI. The first aspect is perception of speech. CI processing is optimised for speech recognition. However, some aspects of speech are not preserved when transmitted thorough a CI which causes CI listeners to have more difficulties in complex acoustic environment to understand speech than normal-hearing listeners. This talk will address the role of reverberation in speech recognition and the ability to recognize talkers through a CI. The second focus is on music perception with a CI. Music still poses a particular problem to CI users. Whereas the CI signal processing roughly preserves the temporal structure such as rhythms, recognition of melodies or certain instruments is significantly harder. This is presumably partly due to the limited frequency resolution of a CI, leading to a reduced pitch percept. In the light of the altered pitch percept with a CI we investigated perception of musical consonance. We have addressed this issue by specific experiments where we focussed on consonance perception for chords in isolation and in successions (cadences). Overall, it is shown that a CI is a powerful utility to restore hearing but that further research is required to overcome the limitations of a CI in complex acoustic environments.

Year: 2020
In session: Hauptvortrag
Pages: 235 to 235