Plasticity of the auditory system with respect to static time differences of the ear signals - part 2

• Applicant: Professor Dr. Stefan Zirn
• Subject Area: Acoustics ; Otolaryngology, Phoniatrics and Audiology
• Term: since 2020
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 452141733

Different hearing devices for the two ears are often required for the therapy of asymmetric hearing loss. Those devices are typically not temporally aligned because of differences in processing delays and/or differences in stimulation sites. E.g., in the case of unilateral hearing loss provided with a unilateral hearing aid (HA), those timing differences are technically barely completely avoidable because current digital HA typically need between 2.8 and 9 ms to process sound. The temporal misalignment constantly superimposes interaural time differences (ITD) and therefore potentially affects sound localization and spatial release of masking (SRM) of speech. The device-related constant interaural time difference is referred to as latency offset (τ_DDM) in the following. In our previous work, we first quantified τ_DDM for several hearing device configurations and later investigated its influence on sound localization. It turned out that even after long-term adaptation to τ_DDM in the case of bimodal cochlear implant (CI) / HA users, sound localization improved when τ_DDM was reduced. Furthermore, during the first funding period (project acronym: PASD), we achieved i) a first size estimation of time windows within which the τ_DDM in unilateral HA provision may range without negatively influencing SRM. ii) We found first evidence for an objective marker of binaural processing with different modalities namely the binaural interaction component (BIC) in a subset of single-sided deaf CI users. Both projects i) and ii) turned out to be very complex in terms of methodology and conduction. To understand the processing of distorted binaural cues (such as ITD and interaural level differences) in the auditory system of listeners with asymmetric hearing loss and asymmetric hearing devices to a larger extent, we hereby apply for funding of the continuation of PASD.

• DFG Programme: Research Grants