TY - JOUR
T1 - Low-frequency and high-frequency cochlear nonlinearity in humans
AU - Gorga, Michael P.
AU - Neely, Stephen T.
AU - Dierking, Darcia M.
AU - Kopun, Judy
AU - Jolkowski, Kristin
AU - Groenenboom, Kristin
AU - Tan, Hongyang
AU - Stiegemann, Bettina
N1 - Funding Information:
Work supported by the NIH (NIDCD R01 2251 and P30 4662). We thank Doug Keefe for providing the software that was used for measurements of middle-ear reflectance. We are grateful for informal discussions of this study with Chris Shera, and to two anonymous reviews that provided many helpful suggestions that improved the manuscript. We would also like to thank Sandy Estee, Alberto Cervantes, and Gwen Watson for their help in recruiting subjects to participate in this study.
PY - 2007
Y1 - 2007
N2 - 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.
AB - 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.
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U2 - 10.1121/1.2751265
DO - 10.1121/1.2751265
M3 - Article
C2 - 17927427
AN - SCOPUS:35248827011
SN - 0001-4966
VL - 122
SP - 1671
EP - 1680
JO - Journal of the Acoustical Society of America
JF - Journal of the Acoustical Society of America
IS - 3
ER -