Christopher A. Shera

Christopher A. Shera

Professor of Otolaryngology-Head and Neck Surgery;Co-Division Chief

Individual similarities and differences in eye-movement-related eardrum oscillations (EMREOs) bioRxiv. 2023 Aug 06. . View in PubMed

The Noise Within: Signal-to-Noise Enhancement via Coherent Wave Amplification in the Mammalian Cochlea ArXiv. 2023 Jul 18. . View in PubMed

Characterizing a Joint Reflection-Distortion OAE Profile in Humans With Endolymphatic Hydrops Ear Hear. 2023 Jul 14. . View in PubMed

Conserved features of eye movement related eardrum oscillations (EMREOs) across humans and monkeys bioRxiv. 2023 May 22. . View in PubMed

Bandpass Shape of Distortion-Product Otoacoustic Emission Ratio Functions Reflects Cochlear Frequency Tuning in Normal-Hearing Mice J Assoc Res Otolaryngol. 2023 06; 24(3):305-324. . View in PubMed

The Remarkable Outer Hair Cell: Proceedings of a Symposium in Honour of WE. Brownell. J Assoc Res Otolaryngol. 2023 04; 24(2):117-127. . View in PubMed

The Long Outer-Hair-Cell RC Time Constant: A Feature, Not a Bug, of the Mammalian Cochlea J Assoc Res Otolaryngol. 2023 04; 24(2):129-145. . View in PubMed

Crucial 3-D viscous hydrodynamic contributions to the theoretical modeling of the cochlear response J Acoust Soc Am. 2023 01; 153(1):77. . View in PubMed

Conserved features of eye movement related eardrum oscillations (EMREOs) across humans and monkeys Philos Trans R Soc Lond B Biol Sci. 2023 09 25; 378(1886):20220340. . View in PubMed

Overturning the mechanisms of cochlear amplification via area deformations of the organ of Corti J Acoust Soc Am. 2022 10; 152(4):2227. . View in PubMed

Characterizing the Relationship Between Reflection and Distortion Otoacoustic Emissions in Normal-Hearing Adults J Assoc Res Otolaryngol. 2022 10; 23(5):647-664. . View in PubMed

Auditory filter shapes derived from forward and simultaneous masking at low frequencies: Implications for human cochlear tuning Hear Res. 2022 07; 420:108500. . View in PubMed

Whistling While it Works: Spontaneous Otoacoustic Emissions and the Cochlear Amplifier J Assoc Res Otolaryngol. 2022 02; 23(1):17-25. . View in PubMed

Interplay between traveling wave propagation and amplification at the apex of the mouse cochlea Biophys J. 2022 08 02; 121(15):2940-2951. . View in PubMed

WHAT MAKES HUMAN HEARING SPECIAL? Front Young Minds. 2022; 10.. View in PubMed

Reflection-Source Emissions Evoked with Clicks and Frequency Sweeps: Comparisons Across Levels J Assoc Res Otolaryngol. 2021 12; 22(6):641-658. . View in PubMed

The Elusive Cochlear Filter: Wave Origin of Cochlear Cross-Frequency Masking J Assoc Res Otolaryngol. 2021 12; 22(6):623-640. . View in PubMed

Cochlear outer hair cell electromotility enhances organ of Corti motion on a cycle-by-cycle basis at high frequencies in vivo Proc Natl Acad Sci U S A. 2021 10 26; 118(43). . View in PubMed

Extended low-frequency phase of the distortion-product otoacoustic emission in human newborns JASA Express Lett. 2021 Jan; 1(1):014404. . View in PubMed

Nonlinear cochlear mechanics without direct vibration-amplification feedback Phys Rev Res. 2020 Feb-Apr; 2(1). . View in PubMed

J Acoust Soc Am. 2020 09; 148(3):1585. . View in PubMed

Asymmetry and Microstructure of Temporal-Suppression Patterns in Basilar-Membrane Responses to Clicks: Relation to Tonal Suppression and Traveling-Wave Dispersion J Assoc Res Otolaryngol. 2020 04; 21(2):151-170. . View in PubMed

The cochlear ear horn: geometric origin of tonotopic variations in auditory signal processing Sci Rep. 2020 11 25; 10(1):20528. . View in PubMed

Effects of Forward- and Emitted-Pressure Calibrations on the Variability of Otoacoustic Emission Measurements Across Repeated Probe Fits Ear Hear. 2019 Nov/Dec; 40(6):1345-1358. . View in PubMed

Variable-rate frequency sweeps and their application to the measurement of otoacoustic emissions J Acoust Soc Am. 2019 11; 146(5):3457. . View in PubMed

Morphological Immaturity of the Neonatal Organ of Corti and Associated Structures in Humans J Assoc Res Otolaryngol. 2019 10; 20(5):461-474. . View in PubMed

Constraints imposed by zero-crossing invariance on cochlear models with two mechanical degrees of freedom J Acoust Soc Am. 2019 09; 146(3):1685. . View in PubMed

On the calculation of reflectance in non-uniform ear canals J Acoust Soc Am. 2019 08; 146(2):1464. . View in PubMed

A comparison of ear-canal-reflectance measurement methods in an ear simulator J Acoust Soc Am. 2019 08; 146(2):1350. . View in PubMed

An analytic physically motivated model of the mammalian cochlea J Acoust Soc Am. 2019 01; 145(1):45. . View in PubMed

Cochlear Frequency Tuning and Otoacoustic Emissions Cold Spring Harb Perspect Med. 2019 02 01; 9(2). . View in PubMed

Probing Apical-Basal Differences in the Human Cochlea Using Distortion-Product Otoacoustic Emission Phase AIP Conf Proc. 2018 May 31; 1965(1). . View in PubMed

Introducing Causality Violation for Improved DPOAE Component Unmixing AIP Conf Proc. 2018 May 31; 1965(1). . View in PubMed

Reflection- and Distortion-Source Otoacoustic Emissions: Evidence for Increased Irregularity in the Human Cochlea During Aging J Assoc Res Otolaryngol. 2018 10; 19(5):493-510. . View in PubMed

Spectral Ripples in Round-Window Cochlear Microphonics: Evidence for Multiple Generation Mechanisms J Assoc Res Otolaryngol. 2018 08; 19(4):401-419. . View in PubMed

Negative-delay sources in distortion product otoacoustic emissions Hear Res. 2018 03; 360:25-30. . View in PubMed

Swept-tone stimulus-frequency otoacoustic emissions: Normative data and methodological considerations J Acoust Soc Am. 2018 01; 143(1):181. . View in PubMed

Temporal Suppression of Clicked-Evoked Otoacoustic Emissions and Basilar-Membrane Motion in Gerbils AIP Conf Proc. 2018; 1965(1). . View in PubMed

The eardrums move when the eyes move: A multisensory effect on the mechanics of hearing Proc Natl Acad Sci U S A. 2018 02 06; 115(6):E1309-E1318. . View in PubMed

Mammalian behavior and physiology converge to confirm sharper cochlear tuning in humans Proc Natl Acad Sci U S A. 2018 10 30; 115(44):11322-11326. . View in PubMed

Dynamics of cochlear nonlinearity: Automatic gain control or instantaneous damping? J Acoust Soc Am. 2017 12; 142(6):3510.. View in PubMed

Characterizing spontaneous otoacoustic emissions across the human lifespan J Acoust Soc Am. 2017 03; 141(3):1874. . View in PubMed

Compensating for ear-canal acoustics when measuring otoacoustic emissions J Acoust Soc Am. 2017 01; 141(1):515. . View in PubMed

Using Cochlear Microphonic Potentials to Localize Peripheral Hearing Loss Front Neurosci. 2017; 11:169. . View in PubMed

Frequency shifts in distortion-product otoacoustic emissions evoked by swept tones J Acoust Soc Am. 2016 08; 140(2):936. . View in PubMed

Relating the Variability of Tone-Burst Otoacoustic Emission and Auditory Brainstem Response Latencies to the Underlying Cochlear Mechanics AIP Conf Proc. 2015 Dec 31; 1703. . View in PubMed

Increasing Computational Efficiency of Cochlear Models Using Boundary Layers AIP Conf Proc. 2015 Dec 31; 1703. . View in PubMed

Iterated intracochlear reflection shapes the envelopes of basilar-membrane click responses J Acoust Soc Am. 2015 Dec; 138(6):3717-22. . View in PubMed

Optimizing swept-tone protocols for recording distortion-product otoacoustic emissions in adults and newborns J Acoust Soc Am. 2015 Dec; 138(6):3785-99. . View in PubMed

Functional modeling of the human auditory brainstem response to broadband stimulation J Acoust Soc Am. 2015 Sep; 138(3):1637-59. . View in PubMed

The spiral staircase: tonotopic microstructure and cochlear tuning J Neurosci. 2015 Mar 18; 35(11):4683-90. . View in PubMed

On the spatial distribution of the reflection sources of different latency components of otoacoustic emissions J Acoust Soc Am. 2015 Feb; 137(2):768-76. . View in PubMed

Increased contralateral suppression of otoacoustic emissions indicates a hyperresponsive medial olivocochlear system in humans with tinnitus and hyperacusis J Neurophysiol. 2014 Dec 15; 112(12):3197-208. . View in PubMed

On the method of lumens J Acoust Soc Am. 2014 Dec; 136(6):3126. . View in PubMed

Otoacoustic-emission-based medial-olivocochlear reflex assays for humans J Acoust Soc Am. 2014 Nov; 136(5):2697-713. . View in PubMed

Macromechanics of Hearing: The Unknown Known AIP Conf Proc. 2014 Jun; 1703. . View in PubMed

Distortion-product otoacoustic emission reflection-component delays and cochlear tuning: estimates from across the human lifespan J Acoust Soc Am. 2014 Apr; 135(4):1950-8. . View in PubMed

Measuring stimulus-frequency otoacoustic emissions using swept tones J Acoust Soc Am. 2013 Jul; 134(1):356-68. . View in PubMed

Basilar-membrane interference patterns from multiple internal reflection of cochlear traveling waves J Acoust Soc Am. 2013 Apr; 133(4):2224-39. . View in PubMed

Nonlinear time-domain cochlear model for transient stimulation and human otoacoustic emission J Acoust Soc Am. 2012 Dec; 132(6):3842-8. . View in PubMed

Probing cochlear tuning and tonotopy in the tiger using otoacoustic emissions J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2012 Aug; 198(8):617-24. . View in PubMed

Obtaining reliable phase-gradient delays from otoacoustic emission data J Acoust Soc Am. 2012 Aug; 132(2):927-43. . View in PubMed

The cochlea as a smart structure Smart Mater Struct. 2012 Jun; 21(6):64001. . View in PubMed

Reflectance of acoustic horns and solution of the inverse problem J Acoust Soc Am. 2012 Mar; 131(3):1863-73. . View in PubMed

On cochlear impedances and the miscomputation of power gain J Assoc Res Otolaryngol. 2011 Dec; 12(6):671-6. . View in PubMed

Tracing Distortion Product (DP) Waves in a Cochlear Model AIP Conf Proc. 2011 Nov; 1403(1):557-562. . View in PubMed

Can a Static Nonlinearity Account for the Dynamics of Otoacoustic Emission Suppression? AIP Conf Proc. 2011 Nov; 1403(1):257-263.. View in PubMed

Frequency selectivity in Old-World monkeys corroborates sharp cochlear tuning in humans Proc Natl Acad Sci U S A. 2011 Oct 18; 108(42):17516-20. . View in PubMed

Distortion products and backward-traveling waves in nonlinear active models of the cochlea J Acoust Soc Am. 2011 May; 129(5):3141-52. . View in PubMed

Forward- and Reverse-Traveling Waves in DP Phenomenology: Does Inverted Direction of Wave Propagation Occur in Classical Models? AIP Conf Proc. 2011; 1403.. View in PubMed

Otoacoustic Estimates of Cochlear Tuning: Testing Predictions in Macaque AIP Conf Proc. 2011; 1403:286-292. . View in PubMed

Auditory sensitivity may require dynamically unstable spike generators: evidence from a model of electrical stimulation J Acoust Soc Am. 2010 Nov; 128(5):EL300-5. . View in PubMed

Otoacoustic estimation of cochlear tuning: validation in the chinchilla J Assoc Res Otolaryngol. 2010 Sep; 11(3):343-65. . View in PubMed

Posture systematically alters ear-canal reflectance and DPOAE properties Hear Res. 2010 May; 263(1-2):43-51. . View in PubMed

Coherent reflection without traveling waves: on the origin of long-latency otoacoustic emissions in lizards J Acoust Soc Am. 2010 Apr; 127(4):2398-409. . View in PubMed

Dynamical instability determines the effect of ongoing noise on neural firing J Assoc Res Otolaryngol. 2009 Jun; 10(2):251-67. . View in PubMed

Otoacoustic emissions in humans, birds, lizards, and frogs: evidence for multiple generation mechanisms J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2008 Jul; 194(7):665-83. . View in PubMed

Testing coherent reflection in chinchilla: Auditory-nerve responses predict stimulus-frequency emissions J Acoust Soc Am. 2008 Jul; 124(1):381-95. . View in PubMed

Cochlear reflectivity in transmission-line models and otoacoustic emission characteristic time delays J Acoust Soc Am. 2007 Dec; 122(6):3554-61. . View in PubMed

Comparing stimulus-frequency otoacoustic emissions measured by compression, suppression, and spectral smoothing J Acoust Soc Am. 2007 Dec; 122(6):3562-75. . View in PubMed

Laser amplification with a twist: traveling-wave propagation and gain functions from throughout the cochlea J Acoust Soc Am. 2007 Nov; 122(5):2738-58. . View in PubMed

Near equivalence of human click-evoked and stimulus-frequency otoacoustic emissions J Acoust Soc Am. 2007 Apr; 121(4):2097-110. . View in PubMed

Allen-Fahey and related experiments support the predominance of cochlear slow-wave otoacoustic emissions J Acoust Soc Am. 2007 Mar; 121(3):1564-75. . View in PubMed

Cochlear traveling-wave amplification, suppression, and beamforming probed using noninvasive calibration of intracochlear distortion sources J Acoust Soc Am. 2007 Feb; 121(2):1003-16. . View in PubMed

Wave propagation patterns in a "classical" three-dimensional model of the cochlea J Acoust Soc Am. 2007 Jan; 121(1):352-62. . View in PubMed

Posture-induced changes in distortion-product otoacoustic emissions and the potential for noninvasive monitoring of changes in intracranial pressure Neurocrit Care. 2006; 4(3):251-7. . View in PubMed

Coherent reflection in a two-dimensional cochlea: Short-wave versus long-wave scattering in the generation of reflection-source otoacoustic emissions J Acoust Soc Am. 2005 Jul; 118(1):287-313. . View in PubMed

J Assoc Res Otolaryngol. 2004 Dec; 5(4):349-59. . View in PubMed

Simultaneous measurement of middle-ear input impedance and forward/reverse transmission in cat J Acoust Soc Am. 2004 Oct; 116(4 Pt 1):2187-98. . View in PubMed

Mechanisms of mammalian otoacoustic emission and their implications for the clinical utility of otoacoustic emissions Ear Hear. 2004 Apr; 25(2):86-97. . View in PubMed

Estimates of human cochlear tuning at low levels using forward and simultaneous masking J Assoc Res Otolaryngol. 2003 Dec; 4(4):541-54. . View in PubMed

The origin of SFOAE microstructure in the guinea pig Hear Res. 2003 Sep; 183(1-2):7-17. . View in PubMed

Mammalian spontaneous otoacoustic emissions are amplitude-stabilized cochlear standing waves J Acoust Soc Am. 2003 Jul; 114(1):244-62. . View in PubMed

Stimulus-frequency-emission group delay: a test of coherent reflection filtering and a window on cochlear tuning J Acoust Soc Am. 2003 May; 113(5):2762-72. . View in PubMed

Revised estimates of human cochlear tuning from otoacoustic and behavioral measurements Proc Natl Acad Sci U S A. 2002 Mar 05; 99(5):3318-23. . View in PubMed

Small tumor virus genomes are integrated near nuclear matrix attachment regions in transformed cells J Virol. 2001 Dec; 75(24):12339-46. . View in PubMed

Intensity-invariance of fine time structure in basilar-membrane click responses: implications for cochlear mechanics J Acoust Soc Am. 2001 Jul; 110(1):332-48. . View in PubMed

Frequency glides in click responses of the basilar membrane and auditory nerve: their scaling behavior and origin in traveling-wave dispersion J Acoust Soc Am. 2001 May; 109(5 Pt 1):2023-34. . View in PubMed

Distortion-product source unmixing: a test of the two-mechanism model for DPOAE generation J Acoust Soc Am. 2001 Feb; 109(2):622-37. . View in PubMed

Interrelations among distortion-product phase-gradient delays: their connection to scaling symmetry and its breaking J Acoust Soc Am. 2000 Dec; 108(6):2933-48. . View in PubMed

Middle ear pathology can affect the ear-canal sound pressure generated by audiologic earphones Ear Hear. 2000 Aug; 21(4):265-74. . View in PubMed

Acoustic mechanisms that determine the ear-canal sound pressures generated by earphones J Acoust Soc Am. 2000 Mar; 107(3):1548-65. . View in PubMed

Evoked otoacoustic emissions arise by two fundamentally different mechanisms: a taxonomy for mammalian OAEs J Acoust Soc Am. 1999 Feb; 105(2 Pt 1):782-98. . View in PubMed

The origin of periodicity in the spectrum of evoked otoacoustic emissions J Acoust Soc Am. 1995 Oct; 98(4):2018-47. . View in PubMed

Noninvasive measurement of the cochlear traveling-wave ratio J Acoust Soc Am. 1993 Jun; 93(6):3333-52. . View in PubMed

Analyzing reverse middle-ear transmission: noninvasive Gedankenexperiments J Acoust Soc Am. 1992 Sep; 92(3):1371-81. . View in PubMed

Middle-ear phenomenology: the view from the three windows J Acoust Soc Am. 1992 Sep; 92(3):1356-70. . View in PubMed

An empirical bound on the compressibility of the cochlea J Acoust Soc Am. 1992 Sep; 92(3):1382-8. . View in PubMed

Phenomenological characterization of eardrum transduction J Acoust Soc Am. 1991 Jul; 90(1):253-62. . View in PubMed

A symmetry suppresses the cochlear catastrophe J Acoust Soc Am. 1991 Mar; 89(3):1276-89. . View in PubMed

Reflection of retrograde waves within the cochlea and at the stapes J Acoust Soc Am. 1991 Mar; 89(3):1290-305. . View in PubMed

Lab Site:


The peripheral auditory system transforms air-borne pressure waves into neural impulses that are interpreted by the brain as sound and speech. The cochlea of the inner ear is a snail-shaped electro-hydromechanical signal amplifier, frequency analyzer, and transducer with an astounding constellation of performance characteristics, including sensitivity to sub-atomic displacements with microsecond mechanical response times; wideband operation spanning three orders-of-magnitude in frequency; an input dynamic range of 120 dB, corresponding to a million-million-fold change in signal energy; useful operation even at signal powers 100 times smaller than the background noise; and ultra-low power consumption (15 µW). All of this is achieved not with the latest silicon technology or by exploiting the power of quantum computers — neither has yet approached the performance of the ear — but by self-maintaining biological tissue, most of which is salty water. How does the ear do it?

The Auditory Physics Group studies how the ear amplifies, analyzes, and creates sound. The goal is not only to understand how the cochlea achieves its astounding sensitivity and dynamic range but to use that knowledge to enhance the power of noninvasive probes of peripheral auditory function (e.g., otoacoustic emissions). Our approach involves a strong, quantitative interplay between theoretical modeling studies and physiological measurements. Ongoing work in the lab focuses on models of cochlear amplification, mechanisms of OAE generation, middle-ear transmission, and comparative studies of cochlear mechanics.
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