Description
Background: The auditory system needs to separate relevant input from noise, a process depending on selective attention. Profound hearing loss aggravates sound separation but can be treated with a Cochlear Implant (CI). Here,we ask whether adaptation to electrical hearing with a CI is accompanied by modulation of the brain’s perceptual and attentional processing?
Methods: Unilateral CI users performed spatial and temporal listening tests within the first six weeks following CI activation and approximately six months thereafter. In addition to clinical and subjective measures of speech comprehension, electroencephalography (EEG) recordings during a passive listening task with amplitude-modulated (AM) sounds and a spatial listening task with competing talkers were collected.
Results: Clinical speech reception scores in quiet improved during the six-months period. Benefits in spatial listening when the CI was switched on versus off were dependent on the spatial arrangement of target speech versus noise. In the EEG, after six months of CI use, the auditory phase-locking relatively decreased in response to slow 4-Hz AM sounds but increased for fast 40-Hz AM sounds. Spatial attention induced a hemispheric lateralization of alpha oscillations (~10 Hz), driven by the hemisphere contralateral to the non-implanted ear.
Discussion: Modulation of neural phase-locking suggests a CI-induced re-balancing of inhibitory and excitatory processes. Stronger alpha power modulation in the hemisphere contralateral to the non-implanted ear might
indicate that unilateral CI users apply attentional enhancement vs suppression predominantly on the input from the non-implanted ear.
Conclusion: The results suggest specific adaptation of bottom-up perceptual processes during the adaptation to listening with a unilateral CI, while effects of top-down attention remain relatively stable. These results will help derive a mechanistic account of how human perception and attention adapt to listening with a CI.
| Period | 27. Sept 2024 |
|---|---|
| Event title | Auditory Science Meeting |
| Event type | Conference |
| Location | Cambridge, United KingdomShow on map |
| Degree of Recognition | International |