Over-attenuating spectral valleys may remove speech information CI users need

Evidence

In general, it seems that SCE produces a detrimental effect in spectral modulation detection and vowel identification in CI users. These results are contrary to the model predictions. Previous studies in the literature give reasons to believe that spectral contrast enhancement would result in a benefit for the chosen tasks. It is possible that spectral valleys are attenuated too much and relevant information required by the CI users to understand speech is lost. These effects are not taken into account by the MPI model, and this could explain the contradictory results between experiments and CI users and modelling results. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1823

Categorization

• QUESTION: Worth asking: does excessive valley attenuation hurt specifically because formant trough locations carry speech cues, or via a more general loudness distortion? The mechanism proposed is left unverified.
• XREF: Connects to reader’s interest in how spectral cues (formant peaks AND valleys) encode speech information cognitively. — connects to: Spectral contrast coding can be enhanced by attenuating valleys while leaving peaks fixed — Dijk, Pim van, Physiology, Psychoacoustics and…, 1831; Deactivating too few channels fails to show performance differences in n-of-m CI strategies
• corroborated: 3 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1823