Abstract: Cochlear implant (CI) speech-recognition outcomes are influenced by various combinations of bottom-up and top-down factors. As such, there is substantial individual variability in CI outcomes. The purpose of this project is to assess elliptical speech as a tool for evaluating bottom-up perceptual acuity in CI users. Noise-vocoded sentence stimuli were presented to 10 normal-hearing (NH) listeners. Stimuli consisted of IEEE sentences that either maintained correct consonant place-of-articulation cues (Intact Speech) or contained consonant “ellipses” that ambiguated spectral cues to consonant place (Elliptical Speech). The “ellipses” replaced each key-word consonant with a new consonant maintaining the same manner and voicing of the original, but with an altered place feature. A concurrent neuroimaging measurement was conducted to estimate cortical activity in bilateral auditory cortex and dorsolateral prefrontal cortex via functional near-infrared spectroscopy (fNIRS). This project tested our hypotheses that: 1) NH participants will successfully detect ellipses in more favorable listening conditions but will be unable to detect ellipses under more degraded listening conditions, and 2) listeners will demonstrate differences in cortical activity in response to Intact vs Elliptical speech depending on the severity of the signal degradation. Preliminary results demonstrate that the detection of ellipses in speech is impacted by the spectral resolution of the signal, and this result is also reflected in listeners’ cortical activity. These results have important implications for CI users whereby elliptical speech is a potential tool for isolating the quality of the bottom-up input from top-down processing of speech. 

These seminars are hosted by the Department of Speech, Lanugage and Hearing Science. 

This year’s SHRP schedule is available here: https://purdue.edu/TPAN/hearing/shrp_schedule 

Titles and abstracts of all SHRP talks are here: https://purdue.edu/TPAN/hearing/shrp_abstracts