Mechanisms of spectrotemporal modulation detection in normal- and hearing-impaired listeners

The origins of the variability between individuals with similar audiograms for understanding speech in noise (SPiN) still remain poorly understood. Solving this problem requires being able to disentangle the respective contributions of the supra-threshold mechanisms recruited along the auditory pathway to process complex signals. Interestingly, recent works have shown that the ability of listeners with hearing loss to detect a spectrotemporal modulation (STM) signal – a noise whose envelope is jointly modulated over time and frequency like in speech - correlates with their SPiN understanding scores even after accounting for their differences in audibility. STMs thus provide an integrated model to assess the supra-threshold mechanisms underlying SPiN deficits. Yet, at present, it remains unknown how STMs are processed by the human auditory system, and how this processing varies between individuals. In this talk, I will present a novel methodological framework we developed to characterize STM processing, combining psychophysical reverse-correlation deployed in the modulation domain with computational modeling tools. I will then discuss results from several experiments conducted in both normal-hearing and hearing-impaired individuals in which this framework was applied. Finally, I will show how this joined experimental-modeling approach could be used to identify the peripheral and central components underlying supra-threshold hearing deficits, thus offering new research avenues.