Format

Send to

Choose Destination
J Acoust Soc Am. 2007 Sep;122(3):1671.

Low-frequency and high-frequency cochlear nonlinearity in humans.

Author information

1
Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA. gorga@boystown.org

Abstract

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 L(dp) for each L2 for each subject and both f2'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.

PMID:
17927427
PMCID:
PMC2440918
DOI:
10.1121/1.2751265
[Indexed for MEDLINE]
Free PMC Article

Supplemental Content

Full text links

Icon for American Institute of Physics Icon for PubMed Central
Loading ...
Support Center