Speech Recognition With the Advanced Combination Encoder and Transient Emphasis Spectral Maxima Strategies in Nucleus 24 Recipients One of the difficulties faced by cochlear implant (CI) recipients is perception of low-intensity speech cues. A. E. Vandali (2001)  has developed the transient emphasis spectral maxima (TESM) strategy to amplify short-duration, low-level sounds. The aim of the present study was to determine whether speech scores would be significantly higher ... Research Article
Research Article  |   June 01, 2005
Speech Recognition With the Advanced Combination Encoder and Transient Emphasis Spectral Maxima Strategies in Nucleus 24 Recipients
 
Author Affiliations & Notes
  • Laura K. Holden
    Washington University, St. Louis, MO
  • Andrew E. Vandali
    Cooperative Research Centre for Cochlear Implant and Hearing Aid Innovation, East Melbourne, Australia
  • Margaret W. Skinner
    Washington University, St. Louis, MO
  • Marios S. Fourakis
    The Ohio State University, Columbus
  • Timothy A. Holden
    Washington University, St. Louis, MO
  • Contact author: Laura K. Holden, Department of Otolaryngology-Head and Neck Surgery, Washington University School of Medicine, 660 South Euclid Avenue, Campus Box 8115, St. Louis, MO 63110. E-mail: holdenl@wustl.edu
Article Information
Hearing & Speech Perception / Acoustics / Hearing Aids, Cochlear Implants & Assistive Technology / Audiologic / Aural Rehabilitation / Speech, Voice & Prosody / Hearing / Research Articles
Research Article   |   June 01, 2005
Speech Recognition With the Advanced Combination Encoder and Transient Emphasis Spectral Maxima Strategies in Nucleus 24 Recipients
Journal of Speech, Language, and Hearing Research, June 2005, Vol. 48, 681-701. doi:10.1044/1092-4388(2005/047)
History: Received January 7, 2004 , Accepted November 15, 2004
 
Journal of Speech, Language, and Hearing Research, June 2005, Vol. 48, 681-701. doi:10.1044/1092-4388(2005/047)
History: Received January 7, 2004; Accepted November 15, 2004
Web of Science® Times Cited: 8

One of the difficulties faced by cochlear implant (CI) recipients is perception of low-intensity speech cues. A. E. Vandali (2001)  has developed the transient emphasis spectral maxima (TESM) strategy to amplify short-duration, low-level sounds. The aim of the present study was to determine whether speech scores would be significantly higher with TESM than with the advanced combination encoder (ACE) strategy fitted using procedures that optimize perception of soft speech and other sounds. Eight adult recipients of the Nucleus 24 CI system participated in this study. No significant differences in scores were seen between ACE and TESM for consonant-vowel nucleus-consonant (CNC) words presented at 55 and 65 dB SPL, for sentences in noise presented at 65 dB SPL at 2 different signal-to-noise ratios, or for closed-set vowels and consonants presented at 60 dB SPL. However, perception of stop consonants within CNC words presented at the lower level (55 dB SPL) was significantly higher with TESM than ACE. In addition, percentage of information transmitted for words at 55 dB SPL was significantly higher with TESM than with ACE for manner and voicing features for consonants in the initial word position. Analysis of closed-set consonants presented at 60 dB SPL revealed percentage of information transmitted for manner was significantly higher with TESM than with ACE. These improvements with TESM were small compared with those reported by Vandali for recipients of the Nucleus 22 CI system. It appears that mapping techniques used to program speech processors and improved processing capabilities of the Nucleus 24 system contributed to soft sounds being understood almost as well with ACE as with TESM. However, half of the participants preferred TESM to ACE for use in everyday life, and all but 1 used TESM in specific listening situations. Clinically, TESM may be useful to ensure the audibility of low-intensity, short-duration acoustic cues that are important for understanding speech, for recipients who are difficult to map, or if insufficient time precludes the use of mapping techniques to increase audibility of soft sound.

Acknowledgments
This research was supported by Grant RO1 DC000581 from the National Institute on Deafness and Other Communication Disorders and by the Commonwealth of Australia through the Cooperative Research Centre for Cochlear Implant and Hearing Aid Innovation (CRC HEAR). Appreciation is expressed to the 8 participants who graciously gave their time and effort to participate in this study, Robert Cowan for his assistance in facilitating the study and preparing the manuscript, John Hawks and Marilyn Demorest for their assistance on earlier drafts of the manuscript, Bob Shannon for the consonant tokens and use of the Condor software, Jim Hillenbrand for the vowel tokens, and CRC HEAR for the loan of the SPEAR3 research system. This research was approved by the Human Studies Committee at Washington University School of Medicine (#02-0882).
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