Low-frequency and high-frequency cochlear nonlinearity in humans

Michael P. Gorga, Stephen T. Neely, Darcia M. Dierking, Judy Kopun, Kristin Jolkowski, Kristin Groenenboom, Hongyang Tan, Bettina Stiegemann

Research output: Contribution to journalArticlepeer-review

32 Scopus citations


Low- and high-frequency cochlear nonlinearity was studied by measuring distortion product otoacoustic emission input/output (DPOAE I/O) functions at 0.5 and 4 kHz in 103 normal-hearing subjects. Behavioral thresholds at both f2's were used to set L2 in dB SL for each subject. Primary levels were optimized by determining the L1 resulting in the largest Ldp for each L2 for each subject and both f 2's. DPOAE I/O functions were measured using L2 inputs from -10 dB SL (0.5 kHz) or -20 dB SL (4 kHz) to 65 dB SL (both frequencies). Mean DPOAE I/O functions, averaged across subjects, differed between the two frequencies, even when threshold was taken into account. The slopes of the I/O functions were similar at 0.5 and 4 kHz for high-level inputs, with maximum compression ratios of about 4:1. At both frequencies, the maximum slope near DPOAE threshold was approximately 1, which occurred at lower levels at 4 kHz, compared to 0.5 kHz. These results suggest that there is a wider dynamic range and perhaps greater cochlear-amplifier gain at 4 kHz, compared to 0.5 kHz. Caution is indicated, however, because of uncertainties in the interpretation of slope and because the confounding influence of differences in noise level could not be completely controlled.

Original languageEnglish (US)
Pages (from-to)1671-1680
Number of pages10
JournalJournal of the Acoustical Society of America
Issue number3
StatePublished - 2007

ASJC Scopus subject areas

  • Arts and Humanities (miscellaneous)
  • Acoustics and Ultrasonics


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