Precedence effect and binaural cue sensitivity in cochlear implanted rats with different hearing experience

26dga180 10.3205/26dga180 urn:nbn:de:0183-26dga1804 Meeting Abstract Precedence effect and binaural cue sensitivity in cochlear implanted rats with different hearing experience Fleiner Fleiner Tim T

Medical Center – University of Freiburg, Medical Faculty, Department of Otolaryngology, Section for Experimental and Clinical Otology, Neurobiological Research Laboratory, Freiburg i. Br., Deutschland

author Buchholz Buchholz Sarah S

author Xavier Xavier Aline A

author Arndt Arndt Susan S

Medical Center – University of Freiburg, Medical Faculty, Department of Otolaryngology, Section for Experimental and Clinical Otology, Freiburg i. Br., Deutschland

author Schnupp Schnupp Jan W. JW

Chinese University of Hong Kong, Department of Otolaryngology, Sha Tin, Hong Kong, Hong Kong Chinese University of Hong Kong, Gerald Choa Neuroscience Institute, Sha Tin, Hong Kong, Hong Kong

author Roßkothen-Kuhl Roßkothen-Kuhl Nicole N

author German Medical Science GMS Publishing House

Düsseldorf

610 20260302 engl This is an Open Access article distributed under the terms of the Creative Commons Attribution 4.0 License. Dieser Artikel ist ein Open-Access-Artikel und steht unter den Lizenzbedingungen der Creative Commons Attribution 4.0 License (Namensnennung). M0642 180 Deutsche Gesellschaft für Audiologie e. V. 28. Jahrestagung der Deutschen Gesellschaft für Audiologie Postersession Oldenburg 20260304 20260306 180 TextSound localization is one of the major challenges for bilateral cochlear implant (CI) users, especially if they suffer from early hearing loss. Their ability to utilize binaural cues, particularly interaural time differences (ITDs), falls below that of their normal hearing peers. Our recent work on neonatally deafened (ND), CI-supplied rats demonstrated excellent ITD sensitivity with remarkably low thresholds (~50 μs) even in the absence of early sensory input, if the CIs present microsecond-accurate ITDs . We could also show that NDCI rats develop excellent sensitivity to interaural level differences (ILDs) . However, to date, it is not known how acoustic hearing experience prior to CI implantation affects the precedence effect, as well as the ITD and ILD sensitivity. To get further insights into sound localization with bilateral CIs and the mechanisms behind it, we investigated binaural cue sensitivity in adult deafened (AD), CI-supplied rats. Additionally, we studied the precedence effect by measuring temporal weighting functions (TWFs) and compared them to TWFs of NDCI and normal hearing rats.ADCI rats (n=4) were deafened during CI implantation in young adulthood. They were trained to lateralize pulse trains with accurate ITDs in the range of ±\'7b40, 60, 80, 100, 120\'7d µs and ILDs in the range of ±\'7b1, 2, 3, 4, 5\'7d dB at a clinical pulse rate of 900 pps. ITDs were presented congruently in both pulse timing and envelope. After three to five weeks of training, rats were tested on their ITD and ILD sensitivity, as well as their temporal weighting. To determine the TWFs, all rats performed a test similar to that developed by Brown and Stecker (2010) . During testing, each pulse in a stimulus burst of eight pulses had a different, randomly selected ITD between ±120 µs, and the rat had to choose freely where the sound came from. TWFs were calculated using multiple regression analysis to determine the perceptual weight of each pulse. ITD and ILD sensitivity and TWFs were compared with those of normally hearing rats and NDCI rats, tested under similar conditions.All ADCI rats developed robust lateralization abilities and developed excellent ITD and ILD sensitivity with behavioral thresholds comparable to NDCI and normally hearing rats. Both CI cohorts showed a reduced precedence effect relative to normally hearing rats.The results indicate that the deaf auditory system can develop good ITD and ILD sensitivity, independent of its prior acoustic hearing experience, if microsecond-accurate ITD information is provided from the outset of biCI stimulation. However, the TWFs were much flatter in both electrically hearing cohorts, suggesting that the precedence effect may require context or domain-specific experience rather than early acoustic experience to develop. Rosskothen-Kuhl N Buck AN Li K Schnupp JW Microsecond interaural time difference discrimination restored by cochlear implants after neonatal deafness 2021 Elife e59300 Rosskothen-Kuhl N, Buck AN, Li K, Schnupp JW. Microsecond interaural time difference discrimination restored by cochlear implants after neonatal deafness. Elife. 2021 Jan 11;10:e59300. DOI: 10.7554/eLife.59300 http://dx.doi.org/10.7554/eLife.59300 Buchholz S Schnupp JWH Arndt S Rosskothen-Kuhl N Interaural level difference sensitivity in neonatally deafened rats fitted with bilateral cochlear implants 2024 Sci Rep 30515 Buchholz S, Schnupp JWH, Arndt S, Rosskothen-Kuhl N. Interaural level difference sensitivity in neonatally deafened rats fitted with bilateral cochlear implants. Sci Rep. 2024 Dec 16;14(1):30515. DOI: 10.1038/s41598-024-82978-4 http://dx.doi.org/10.1038/s41598-024-82978-4 Brown and Stecker Temporal weighting of interaural time and level differences in high-rate click trains J. Acoust. Soc 2010 Am 332-341 Brown and Stecker. Temporal weighting of interaural time and level differences in high-rate click trains J. Acoust. Soc. Am. 2010;128:332-341. DOI: 10.1121/1.3436540 http://dx.doi.org/10.1121/1.3436540 0 0 0 0