Speaker
Description
The ability to understand speech in adverse listening conditions, such as in the presence of masking noise, is severely degraded in people with hearing loss. The mechanisms that underly these speech deficits are still not fully understood. A healthy auditory efferent system has been argued to facilitate understanding speech in noise. Evidence from computational auditory models that include the efferent system suggests that efferent suppression might play a significant role in the representation of speech sounds in the auditory pathway. However, the relationship between efferent strength, hearing loss, and reduced speech understanding is still debated, partly because measuring efferent suppression is not straightforward in participants with hearing loss. In this contribution we apply a new method for measuring efferent strength using click-evoked otoacoustic emissions (CEOAEs). Our approach is to compare the magnitude of long-latency CEOAEs for pairs of clicks, before and after an efferent-eliciting tone. In a cohort of participants with a diverse range of hearing status, we studied the influence of click level and elicitor level on the measured efferent strength. Different descriptors of efferent strength in terms of their on-frequency magnitude as well as the frequency range of the suppressing effect were considered. Future studies will extend this approach to study the relationship between hearing loss and efferent strength and its potential relationship with speech intelligibility.