Spectral valley over-attenuation may explain why contrast enhancement harms CI users

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. Still, it is possible that the SCE factors selected where too high, for this reason we think that a follow-up study should investigate whether lower amounts SCE can provide improvements in CI users. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1889

Categorization

• QUESTION: Two competing explanations are offered (valley over-attenuation vs. too-high SCE factors) but left unresolved; a natural question to chase.
• SEED: Angle: ‘When a good idea fails in practice’ — how simulation models that omit real processing constraints mislead engineering design in hearing-aid and implant development.