Relationship between perception of spectral ripple and speech recognition in cochlear implant and vocoder listeners
Document Type
Article
Abstract
Spectral resolution has been reported to be closely related to vowel and consonant recognition in cochlear implant (CI) listeners. One measure of spectral resolution is spectral modulation threshold (SMT), which is defined as the smallest detectable spectral contrast in the spectral ripple stimulus. SMT may be determined by the activation pattern associated with electrical stimulation. In the present study, broad activation patterns were simulated using a multi-band vocoder to determine if similar impairments in speech understanding scores could be produced in normal-hearing listeners. Tokens were first decomposed into 15 logarithmically spaced bands and then re-synthesized by multiplying the envelope of each band by matched filtered noise. Various amounts of current spread were simulated by adjusting the drop-off of the noise spectrum away from the peak (40-5 dBoctave). The average SMT (0.25 and 0.5 cyclesoctave) increased from 6.3 to 22.5 dB, while average vowel identification scores dropped from 86% to 19% and consonant identification scores dropped from 93% to 59%. In each condition, the impairments in speech understanding were generally similar to those found in CI listeners with similar SMTs, suggesting that variability in spread of neural activation largely accounts for the variability in speech perception of CI listeners.
Medical Subject Headings
Acoustic Impedance Tests; Acoustic Stimulation; Adult; Auditory Threshold (physiology); Cochlear Implantation; Computer Simulation; Hearing (physiology); Humans; Language; Noise; Reference Values; Sound; Sound Localization; Speech Intelligibility
Publication Date
8-1-2007
Publication Title
The Journal of the Acoustical Society of America
E-ISSN
1520-8524
Volume
122
Issue
2
First Page
982
Last Page
91
PubMed ID
17672646
Digital Object Identifier (DOI)
10.1121/1.2749413
Recommended Citation
Litvak, Leonid M.; Spahr, Anthony J.; Saoji, Aniket A.; and Fridman, Gene Y., "Relationship between perception of spectral ripple and speech recognition in cochlear implant and vocoder listeners" (2007). ENT and Skull Base Surgery. 151.
https://scholar.barrowneuro.org/ent-and-skull-base-surgery/151