Nicole Rosskothen-Kuhl, Neurobiology, University Medical Center Freiburg | Spatial hearing with cochlear implant(s): Interaural time difference discrimination restored by CIs after neonatal deafnesss
| When |
Dec 11, 2018
from 05:15 PM to 06:15 PM |
|---|---|
| Where | Lecture Hall, Bernstein Center Freiburg |
| Contact Name | Prof. Dr. Stefan Rotter |
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Abstract
Cochlear implants (CIs) restore a degree of functional hearing in many patients suffering from severe or profound hearing loss. These devices are often highly effective at enabling users to understand speech. But they nevertheless fail to restore normal or near-normal hearing capabilities in a number of respects, including the ability to use fine interaural time differences (ITDs) for spatial hearing. To derive maximum benefit from CIs, further research is needed in animal models to understand how parameters such as interaural synchronization influence the binaural processing in central auditory hubs of CI patients. We used neonatally deafened rats as a model to study electrophysiological and behavioral changes of the central auditory system under binaural CI stimulation.
Rats received CIs in young adulthood and were either actively stimulated during two-alternative forced choice stimulus lateralization task training, or they were passively stimulated with simultaneous recordings of ITD tuning in their inferior colliculus (IC). As a result, we found for deafened, CI-implanted rats microsecond ITD sensitivity when provided with precise ITD cues right from the start of stimulation. In addition, they can be trained to localize ITD stimuli with behavioral thresholds in the order of 50 μs. This ITD performance compares well with that achieved by normal hearing rats. By this, we demonstrated that even a hearing inexperienced auditory system can develop ITD sensitivity if using CI stimulation with appropriate binaural parameters. These results have important clinical implications as they suggest that it should in principle be possible to incorporate ITD coding into future CI designs and thus to improve the sound localization performance of bilateral CI users.
Literature
- Hancock et al., J Neuroscience, 2010 (Link)
