Veranstaltung
Hearing in Two Worlds: Electrophysiological and psychophysical studies on electric and acoustic stimulation| Titel der Veranstaltung | Hearing in Two Worlds: Electrophysiological and psychophysical studies on electric and acoustic stimulation |
| Reihe | SFB889 Colloquium |
| Veranstalter | SFB889 |
| Referent/in | Dr. Youssef Adel |
| Einrichtung Referent/in | University Hospital Tübingen |
| Veranstaltungsart | Vortrag |
| Kategorie | Forschung |
| Anmeldung erforderlich | Ja |
| Beschreibung | Over the last two decades, the population of hearing-impaired people undergoing cochlear implantation has greatly increased. While cochlear implants (CIs) originally targeted patients with bilateral profound deafness, indication criteria now include patients with significant residual acoustic hearing in their a) ipsilateral or b) contralateral ear. Patients with ipsilateral, residual low-frequency hearing can be provided with a CI to facilitate combined electric and acoustic stimulation, with well-established advantages over electric stimulation alone. Still, residual hearing is often only partially preserved due to, inter alia, acute mechanical trauma during implantation. Possibilities of intraoperative monitoring using electro¬cochleography have been extensively studied in CI patients, primarily using the ongoing outer hair cell response to low-frequency tone bursts, i.e., cochlear microphonics. In contrast, neural phase-locking to the ongoing response as well as the neural transient response, i.e., compound action potential (CAP), were previously found to be less prominent or sometimes absent, thus falling short of providing useful contribution to monitoring analysis. In an electrophysiological study in guinea pigs, we investigated band-limited chirp stimuli to better synchronize neural firing and thus provide more robust CAP responses and improve CAP sensitivity to simulated mechanical trauma during cochlear implantation. This study provides a proof of principle for using chirp-evoked CAP as a neural measure in CI patients with ipsilateral residual hearing. In the CI population with normal or near-normal hearing in their contralateral ear, i.e., single-sided deafness (SSD), fusion between electric and acoustic hearing may strongly depend on delivering frequency information to each CI electrode that corresponds to its intracochlear location. One way to achieve this is by matching electric and acoustic pitch where subjects compare the percept elicited by electric stimulation of a single CI electrode with that evoked by an acoustic stimulus. Previous studies generally used sinusoids as acoustic stimuli and have shown that electric-acoustic pitch matching usually produces very variable data, which can be traced back to methodological limitations or the choice of the acoustic stimulus type. The percept elicited by electric stimulation is presumed to be closer to a wideband stimulus rather than a sinusoid. And it has been previously shown that pitch comparisons between sounds with different timbres is subjected to various types of range biases. In a psychophysical study, we introduced a method to minimize non-sensory bias and investigated the effect of different acoustic stimulus types on the frequency and variability of electric-acoustic pitch matches in CI users with SSD. The results provide evidence that the choice of stimulus type can have a significant effect on pitch matches. Furthermore, the data suggest pitch salience as a confounding factor and impel further research to find an acoustic stimulus that better mimics the percept elicited by electric stimulation. |
| Zeit | Beginn: 14.12.2021, 14:00 Uhr Ende: 14.12.2021 , 15:00 Uhr |
| Ort | online (ZOOM) |
| Kontakt |
0551 3961942 sfb889@med.uni-goettingen.de |
| Externer Link | http://www.sfb889.uni-goettingen.de |
| Dateianhang | SFB889 colloquium_Adel.pdf |