Tim Fleiner: Does Spatial Hearing with Bionic Ears Change with Temporal Inaccuracy?
| When |
Oct 08, 2024
from 05:15 PM to 06:00 PM |
|---|---|
| Where | Bernstein Center, Lecture Hall, ground floor, Hansastr. 9a |
| Contact Name | Gundel Jaeger |
| Contact Phone | 0761 203 9549 |
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Abstract
By 2050 almost 2.5 billion people are expected to have some degree of hearing loss (WHO 2024). With the help of the clinically most successful brain-machine interface of our age, the cochlear implant (CI), more than one million patients with severe-to-profound hearing loss have already been able to learn to hear. However, hearing with two bionic ears is still far away from normal hearing. To localize sound sources in the horizontal plane, the auditory system uses two different binaural cues: interaural level differences (ILDs) and interaural time differences (ITDs). In human patients with cochlear implanted ears, sound localization is one of the major challenges, especially if they suffer from early hearing loss. One reason for this is their impaired sensitivity to ITDs, which could be a consequence of inadequate presentation of temporal information by clinical CI devices. We hypothesize that optimized CI stimulation strategies could improve spatial hearing in CI users. Indeed, preliminary work from our group has shown that ITD sensitivity can be significantly improved when binaural input is presented with microsecond precision from the onset of CI stimulation. However, state of the art synchronization strategies of CI devices cannot provide microsecond precise ITD cues. We are investigating how much temporal imprecision the deaf auditory system can tolerate to develop a good ITD sensitivity and used the animal model rat to answer this question.
Our preliminary results showed an improved spatial hearing performance when ITDs were jittered to a certain extent. Furthermore, the auditory system of CI-supplied rats seemed to reduce the effect of jittered ITDs by changing their lateralization strategy. Our findings thereby underline the importance of synchronizing both implant devices, while tolerating a small binaural temporal inaccuracy to improve the spatial hearing in future CI patients.