For example, there are a limited number of place-specific electrodes in the cochlea, resulting in poor specification of the spectral place code along the basilar membrane. This aspect of hearing has clear implications for speech perception, as many speech sounds (e.g., /b/-/d/-/ɡ/, /p/-/t/-/k/, most vowels) vary by spectral cues such as the frequency of formant peaks and other global spectral properties.įor people who use cochlear implants (CIs), spectral resolution is known to be degraded for multiple reasons. Spectral resolution in hearing is the perceptual ability of a listener to distinguish between sounds that differ in pitch or other qualities in the spectral (i.e., frequency) domain.

The current approach to testing functional spectral resolution uses auditory cues that are known to be important for speech categorization, and can thus potentially serve as the basis upon which CI processing strategies and innovations are tested. Cue-weighting results showed moderately good correspondence with word recognition scores. Compared to NH listeners, CI listeners relied less on formant transitions, and more on spectral tilt. The use of formant cues was greatest for NH listeners for unprocessed speech, and declined in the two vocoded conditions. Perceptual weighting of the two cues was modeled with mixed-effects logistic regression, and was found to systematically vary with spectral resolution.

Participants included 19 CI listeners and 10 listeners with normal hearing (NH), for whom spectral resolution was explicitly controlled using a noise vocoder with variable carrier filter widths to simulate electrical current spread. Higher weighting of the formant cues was used as an index of better spectral cue perception. Specifically, perception of the /ba/-/da/ contrast was tested using two spectral cues: Formant transitions (a fine-resolution cue) and spectral tilt (a coarse-resolution cue). In this study, spectral properties of speech sounds were used to test functional spectral resolution in people who use cochlear implants (CIs).

Original icq sounds