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Semin Hear 1999; 20(3): 237-252
DOI: 10.1055/s-0028-1082939
Copyright © 1999 by Thieme Medical Publishers, Inc.

Effect of Output Limiting Levels upon the Speech Perception Skills of Congenitally Hearing Impaired Adolescents

Susan Lear* , Dianne Toe† , Field Rickards‡ , Richard C. Seewald§
  • *Taralye, The Advisery Council for Children with Impaired Hearing (VIC), Melbourne, Australia
  • †Renwick College, University of Newcastle at the Royal Institute for Deaf and Blind Children, Australia
  • ‡University of Melbourne, Australia
  • §University of Western Ontario, Canada
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Publication Date:
01 August 2008 (online)

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Abstract

The present study investigated the impact of different output-limiting levels on the speech-perception skills of three severely hearing-impaired adolescents. It also explored the impact of reducing SSPL settings on aided sound-field thresholds and hearing-aid gain. AGCo settings were gradually decreased using the participant's own programmable hearing aids. At each SSPL setting, speech perception was measured in quiet using a computer based 50-item CNC word test. Changes in aided sound-field thresholds, gain, and SPLograms were also measured. Speech-perception scores decreased with reductions in SSPL settings, with the most marked deterioration occurring at the lowest SSPL settings. Inspection of speech SPLograms indicated that these students were able to achieve maximum speech perception over a wide dynamic range; however, as the dynamic range became more limited, speechperception skills began to deteriorate. Reduced SSPL produced a reduction in gain. When the gain reductions reduced the aided articulation index to about 0.4, a significant reduction in speech perception was observed.

Keywords:

Output limiting - speech perception - dynamic range