The internal representation of spectral contrast in hearing‐impaired listeners

1994 ◽  
Vol 95 (6) ◽  
pp. 3518-3528 ◽  
Author(s):  
Van Summers ◽  
Marjorie R. Leek
Keyword(s):  
Internal Representation ◽  
Hearing Impaired ◽  
Spectral Contrast

Perception of Spectral Contrast by Hearing-Impaired Listeners

2005 ◽  
Vol 48 (4) ◽  
pp. 910-921 ◽  
Author(s):  
Laura E. Dreisbach ◽  
Marjorie R. Leek ◽  
Jennifer J. Lentz
Keyword(s):  
Hearing Loss ◽  
Internal Representation ◽  
Normal Hearing ◽  
Stimulus Level ◽  
Hearing Impaired ◽  
Frequency Resolution ◽  
Spectral Peak ◽  
Control Group ◽  
Complex Sounds ◽  
Spectral Contrast

The ability to discriminate the spectral shapes of complex sounds is critical to accurate speech perception. Part of the difficulty experienced by listeners with hearing loss in understanding speech sounds in noise may be related to a smearing of the internal representation of the spectral peaks and valleys because of the loss of sensitivity and an accompanying reduction in frequency resolution. This study examined the discrimination by hearing-impaired listeners of highly similar harmonic complexes with a single spectral peak located in 1 of 3 frequency regions. The minimum level difference between peak and background harmonics required to discriminate a small change in the spectral center of the peak was measured for peaks located near 2, 3, or 4 kHz. Component phases were selected according to an algorithm thought to produce either highly modulated (positive Schroeder) or very flat (negative Schroeder) internal waveform envelopes in the cochlea. The mean amplitude difference between a spectral peak and the background components required for discrimination of pairs of harmonic complexes (spectral contrast threshold) was from 4 to 19 dB greater for listeners with hearing impairment than for a control group of listeners with normal hearing. In normal-hearing listeners, improvements in threshold were seen with increasing stimulus level, and there was a strong effect of stimulus phase, as the positive Schroeder stimuli always produced lower thresholds than the negative Schroeder stimuli. The listeners with hearing loss showed no consistent spectral contrast effects due to stimulus phase and also showed little improvement with increasing stimulus level, once their sensitivity loss was overcome. The lack of phase and level effects may be a result of the more linear processing occurring in impaired ears, producing poorer-than-normal frequency resolution, a loss of gain for low amplitudes, and an altered cochlear phase characteristic in regions of damage.

Minimum spectral contrast for vowel identification by normal and hearing‐impaired listeners

1985 ◽  
Vol 78 (S1) ◽  
pp. S81-S81
Author(s):  
M. R. Leek ◽  
M. F. Dorman ◽  
Q. Summerfield
Keyword(s):  
Hearing Impaired ◽  
Vowel Identification ◽  
Spectral Contrast

Minimum spectral contrast for vowel identification by normal‐hearing and hearing‐impaired listeners

1987 ◽  
Vol 81 (1) ◽  
pp. 148-154 ◽  
Author(s):  
Marjorie R. Leek ◽  
Michael F. Dorman ◽  
Quentin Summerfield
Keyword(s):  
Normal Hearing ◽  
Hearing Impaired ◽  
Vowel Identification ◽  
Spectral Contrast

scholarly journals Effects of Signal Level and Spectral Contrast on Vowel Formant Discrimination for Normal-Hearing and Hearing-Impaired Listeners

2013 ◽  
Vol 22 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Ashley Woodall ◽  
Chang Liu
Keyword(s):  
Hearing Impairment ◽  
American English ◽  
Normal Hearing ◽  
Hearing Impaired ◽  
Spectral Contrast ◽  
Vowel Formant ◽  
English Vowels ◽  
Spectral Enhancement ◽  
The Individual

Purpose The aim of this study was to determine whether increasing the overall speech level or the individual spectral contrasts of vowel sounds can improve vowel formant discrimination for listeners both with and without normal hearing. Method Thresholds of vowel formant discrimination were examined for the F2 frequencies of 3 American English vowels for listeners with and without normal hearing. Spectral contrasts of the F2 were enhanced by 3, 6, and 9 dB. Vowel stimuli were presented at 70 and 90 dB SPL. Results The thresholds of listeners with hearing impairment were reduced significantly after spectral enhancement was implemented, especially at 90 dB SPL, whereas normal-hearing listeners did not benefit from spectral enhancement. Conclusion These results indicate that a combination of spectral enhancement of F2 and high speech level is most beneficial to improve vowel formant discrimination for listeners with hearing impairment.

Sign in / Sign up

Export Citation Format

Share Document