Application of the Envelope Difference Index to Spectrally Sparse Speech PurposeAmplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was ... Article
Article  |   June 01, 2012
Application of the Envelope Difference Index to Spectrally Sparse Speech
 
Author Affiliations & Notes
  • Pamela Souza
    Northwestern University, Evanston, IL
  • Eric Hoover
    Northwestern University, Evanston, IL
  • Frederick Gallun
    National Center for Rehabilitative Auditory Research, Portland VA Medical Center, Portland, OR
  • Correspondence to Pamela Souza: p-souza@northwestern.edu
  • Editor: Robert Schlauch
    Editor: Robert Schlauch×
  • Associate Editor: Van Summers
    Associate Editor: Van Summers×
Article Information
Hearing
Article   |   June 01, 2012
Application of the Envelope Difference Index to Spectrally Sparse Speech
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 824-837. doi:10.1044/1092-4388(2011/10-0301)
History: Received October 27, 2010 , Revised March 21, 2011 , Accepted October 6, 2011
 
Journal of Speech, Language, and Hearing Research, June 2012, Vol. 55, 824-837. doi:10.1044/1092-4388(2011/10-0301)
History: Received October 27, 2010; Revised March 21, 2011; Accepted October 6, 2011
Web of Science® Times Cited: 7

PurposeAmplitude compression is a common hearing aid processing strategy that can improve speech audibility and loudness comfort but also has the potential to alter important cues carried by the speech envelope. In previous work, a measure of envelope change, the Envelope Difference Index (EDI; Fortune, Woodruff, & Preves, 1994), was moderately related to recognition of spectrally robust consonants. This follow-up study investigated the relationship between the EDI and recognition of spectrally sparse consonants.

MethodStimuli were vowel-consonant-vowel tokens processed to reduce spectral cues. Compression parameters were chosen to achieve a range of EDI values. Recognition was measured for 20 listeners with normal hearing.

ResultsBoth overall recognition and perception of consonant features were reduced at higher EDI values. Similar effects were noted with noise-vocoded and sine-vocoded processing and regardless of whether periodicity cues were available.

ConclusionThe data provide information about the acceptable limits of envelope distortion under constrained conditions. These limits can be used to consider the impact of envelope distortions in situations where other cues are available to varying extents.

Acknowledgments
This work was supported by National Institutes of Health Grant R01 DC0060014 to Pamela Souza, by Department of Veterans Affairs Rehabilitation Research and Development Service Grant C4963W to Frederick Gallun, and by the National Center for Rehabilitative Auditory Research. We thank Steve Armstrong and the Gennum Corporation for providing the hearing aid simulation software; Stuart Rosen for sharing the FIX program and vocoding algorithms; and Ashley Arrington, Alexandra Dykhouse, Louisa Ha, and Marcee Wickline for assistance in data collection.
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