Effects of high sound levels on responses to the vowel /ε/ in cat auditory nerve

Jeff C. Wong, Roger L. Miller, Barbara M. Calhoun, Murray B. Sachs, Eric D. Young

Research output: Contribution to journalArticle

Abstract

The vowel /ε/ was used to study auditory-nerve responses at high sound levels (60-110 dB). By changing the playback sampling rate of the stimulus, the second formant (F2) frequency was set at best frequency (BF) for fibers with BFs between 1 and 3 kHz. For vowel stimuli, auditory-nerve fibers tend to phase-lock to the formant component nearest the fiber's BF. The responses of fibers with BFs near F2 are captured by the F2 component, meaning that fibers respond as if the stimulus consisted only of the F2 component. These narrowband responses are seen up to levels of 80-100 dB, above which a response to F1 emerges. The F1 response grows, at the expense of the F2 response, and is dominant at the highest levels. The level at which the F1 response appears is BF dependent and is higher at lower BFs. This effect appears to be suppression of the F2 response by F1. At levels near 100 dB, a component 1/component 2 transition is observed. All components of the vowel undergo the transition simultaneously, as judged by the 180°phase inversion that occurs at the C2 transition. Above the C2 threshold, a broadband response to many components of the vowel is observed. These results demonstrate that the neural representation of speech in normal ears is degraded at high sound levels, such as those used in hearing aids.

Original languageEnglish (US)
Pages (from-to)61-77
Number of pages17
JournalHearing Research
Volume123
Issue number1-2
DOIs
Publication statusPublished - Sep 1998

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Keywords

  • Auditory nerve
  • Component 1/component 2 transition
  • Loud sound
  • Synchrony capture
  • Two-tone suppression
  • Vowel encoding

ASJC Scopus subject areas

  • Sensory Systems

Cite this

Wong, J. C., Miller, R. L., Calhoun, B. M., Sachs, M. B., & Young, E. D. (1998). Effects of high sound levels on responses to the vowel /ε/ in cat auditory nerve. Hearing Research, 123(1-2), 61-77. https://doi.org/10.1016/S0378-5955(98)00098-7