Proceedings of Meetings on Acoustics

Older adults experience speech perception difficulties that are not explained by audiometric thresholds. One hypothesis is that temporal processing deficits contribute to speech-in-noise difficulties. To test this, threshold for mistuning was measured for a component within a complex of unresolved harmonics a cue that likely depends on sensitivity to envelope perturbations. The complex comprised harmonics 12-16 of a 100-Hz or 200-Hz fundamental, and the duration was either 170-, 340-, or 680-ms. Presentation level was 70 dB SPL. The starting phases of all components were randomized on each presentation. The 3AFC procedure adaptively varied the mistuning of harmonic 14 to obtain the frequency-shift threshold. Younger and older listeners with audiometrically normal hearing participated. The expectation was that older adults would require greater mistuning to detect changes in envelope periodicity and that this would be more evident at shorter durations. Preliminary results support an overall effect of age as well as effects of fundamental frequency and duration. Results will be considered in the context of parallel speech-evoked ABR studies being undertaken in this population that point to age-related deficits in envelope processing, possibly driven by poor encoding of unresolved harmonics. (Work supported by NIDCD 1-F32-DC012217-01A1 & 5-R01-DC001507).