Spectral contrast degradation in CIs impairs formant detection for speech

Evidence

Spectral contrast is defined as the level difference between peaks and valleys in the spectrum. In CIs, spectral contrast is degraded because of the limited number of stimulation electrodes and overlapping electric fields activating the nervous system through the bony structure of the cochlea. This might reduce the differences in amplitudes between peaks and valleys in the input making it more difficult to locate spectral dominance (i.e., formants) which provide crucial cues to speech intelligibility and instrument identification. Loizou and Poroy 2001 showed that CI users need a higher spectral contrast than normal hearing listeners in vowel identification tasks. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1827

Spectral contrast is defined as the level difference between peaks and valleys in the spectrum. In CIs, spectral contrast is degraded because of the limited number of stimulation electrodes and overlapping electric fields activating the nervous system through the bony structure of the cochlea. This might reduce the differences in amplitudes between peaks and valleys in the input making it more difficult to locate spectral dominance (i.e., formants) which provide crucial cues to speech intelligibility and instrument identification. — Dijk, Pim van, Physiology, Psychoacoustics and…, 1823

Categorization

• DEFINE: Defines spectral contrast as the peak-to-valley level difference in the spectrum, the core concept of the chapter.
• XREF: Connects to the reader’s noise/silence work on how degraded spectral information shapes perception in impaired vs normal hearing.
• corroborated: 2 independent passages support this claim — Dijk, Pim van, Physiology, Psychoacoustics and…, 1827; Dijk, Pim van, Physiology, Psychoacoustics and…, 1823