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Audition et Implant cochléaire| old_uid | 5463 |
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| title | Audition et Implant cochléaire |
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| start_date | 2008/10/24 |
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| schedule | 10h30-12h30 |
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| online | no |
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| location_info | salle 3202 |
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| summary | It is well known that the effectiveness of hearing devices in improving communication ability varies considerably between people who have similar hearing levels for simple tones. This is particularly true for cochlear implant (CI) recipients, who can be greatly affected by the physiological effects of auditory deprivation on peripheral and central auditory pathways. In this presentation I will review research aimed at assessing and understanding the perceptual effects of changes in the auditory pathway due to deafness.
At the peripheral level, many cochlear implantees have < 10% of surviving spiral ganglion cells. Histological studies have found no correlation between gross outcome with the CI and peripheral nerve survival. However, as CI design moves towards very place-focussed nerve activation and much higher rates of stimulation, this will no doubt be an important variable affecting both outcome or optimal fitting strategy. One way to assess peripheral neural survival in current (alive!) CI users is to measure the psychophysical or electrophysiological effects of changes in electrical pulse duration and interphase gap.
The ability of the ‘deaf’ auditory system to convey temporal information in speech signals can also be highly compromised in some individuals. Auditory Dis-synchrony is an extreme example of this. CIs can ameliorate this condition by restoring neural synchrony provided that the site of pathology is peripheral to the auditory nerve. An assessment of temporal resolution ability can predict whether a child will benefit from standard acoustic hearing devices, or alternatively would benefit from implantation.
Finally, the outcome of CIs tends to be better in people with more residual hearing and shorter durations of deafness. Is this an effect of having better peripheral nerve survival or of having less central auditory changes due to auditory deprivation? Also, what factors will determine whether such a person can gain significant benefit from combining acoustic and electric hearing? Some evidence is now emerging to begin to answer these questions. |
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| responsibles | Gervais |
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