ORCID Profile
0000-0002-5827-9433
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Publisher: AIP
Date: 2011
DOI: 10.1063/1.3658145
Publisher: Elsevier BV
Date: 04-2003
DOI: 10.1016/S0378-5955(03)00064-9
Abstract: In humans, distortion product otoacoustic emissions (DPOAEs) at frequencies lower than the f(2) stimulus frequency are a composite of two separate sources, these two sources involving two distinctly different mechanisms for their production: non-linear distortion and linear coherent reflection [Talmadge et al., J. Acoust. Soc. Am. 104 (1998) 1517-1543 Talmadge et al., J. Acoust. Soc. Am. 105 (1999) 275-292 Shera and Guinan, J. Acoust. Soc. Am. 105 (1999) 332-348 Kalluri and Shera, J. Acoust. Soc. Am. 109 (2001) 662-637]. In rodents, DPOAEs are larger, consistent with broader filters however the evidence for two separate mechanisms of DPOAE production as seen in humans is limited. In this study, we report DPOAE litude and phase fine structure from the guinea pig with f(2)/f(1) held constant at 1.2 and f(2) swept over a range of frequencies. Inverse Fast Fourier Transform analysis and time-domain windowing were used to separate the two components. Both the 2f(1)-f(2) DPOAE and the 2f(2)-f(1) DPOAE were examined. It was found that, commensurate with human data, the guinea pig DPOAE is a composite of two components arising from different mechanisms. It would appear that the 2f(1)-f(2) emission measured in the ear canal is usually dominated by non-linear distortion, at least for a stimulus frequency ratio of 1.2. The 2f(2)-f(1) DPOAE exhibits litude fine structure that, for the animals examined, is predominantly due to the variation in litude of the place-fixed component. Cochlear delay times appear consistent with a linear coherent reflection mechanism from the distortion product place for both the 2f(1)-f(2) and 2f(2)-f(1) place-fixed components.
Publisher: Acoustical Society of America (ASA)
Date: 03-2009
DOI: 10.1121/1.3075551
Abstract: Quantifying how the sound delivered to the ear canal relates to hearing threshold has historically relied on acoustic calibration in physical assemblies with an input impedance intended to match the human ear (e.g., a Zwislocki coupler). The variation in the input impedance of the human ear makes such a method of calibration questionable. It is preferable to calibrate the acoustic signal in each ear in idually. By using a calibrated sound source and microphone, the acoustic input impedance of the ear can be determined, and the sound delivered to the ear calibrated in terms of either (i) the incident sound pressure wave or (ii) that portion of the incident sound pressure wave transmitted to the middle ear and cochlea. Hearing thresholds expressed in terms of these quantities are reported, these in situ calibrations not being confounded by ear canal standing waves. Either would serve as a suitable replacement for the current practice of hearing thresholds expressed in terms of sound pressure level calibrated in a 6cc or 2cc coupler.
Publisher: Elsevier BV
Date: 02-2004
Publisher: Acoustical Society of America (ASA)
Date: 2008
DOI: 10.1121/1.2804635
Abstract: A pervasive theme in the literature for the transient evoked otoacoustic emission (TEOAE) measured from the human ear canal has been one of the emission arising solely (or largely) from a single, place-fixed mechanism. Here TEOAEs are reported measured in the absence of significant stimulus contamination at stimulus onset, providing for the identification of a TEOAE response beginning within the time window that is typically removed by windowing. Contrary to previous studies, it was found that in humans, as has previously been found in guinea pig, the TEOAE appears to arise from two generation mechanisms, the relative contributions of these two mechanisms being time and stimulus-level dependent. The method of windowing the earliest part of the ear canal measurement to remove stimulus artifact removes part of the TEOAE i.e., much of the component arising from a nonlinear generation mechanism. This reconciliation of TEOAE origin is consistent with all OAEs in mammals arising in a stimulus-level dependent manner from two mechanisms of generation, one linear, one nonlinear, as suggested by Shera and Guinan [J. Acoust. Soc. Am. 105, 782–798 (1999)].
Publisher: WORLD SCIENTIFIC
Date: 02-2003
Publisher: Acoustical Society of America (ASA)
Date: 07-1998
DOI: 10.1121/1.423243
Abstract: This study examined the transient-evoked otoacoustic emission obtained in response to a click stimulus presented in combination with a pure tone in the guinea pig. Low-pass filtered click waveforms were digitally generated using a sin(t)/t function windowed over 3 ms with an elevated cosine envelope. Transient-evoked otoacoustic emissions were obtained using the nonlinear derived response technique. Phase locked pure tones of various frequencies at ∼70 dB SPL were electrically mixed with electrical clicks, with the pure tone present only for the three lower level stimuli in the train of four stimuli. Enhancement in the litude of the response spectrum at frequencies which corresponded to regions of the basilar membrane apical to the tone was observed with the addition of the tone. This finding is inconsistent with the transient-evoked otoacoustic emission being the result of independent generators. It suggests that intermodulation distortion energy may contribute to the transient-evoked otoacoustic emission, the enhancement in the emission response spectrum at frequencies below the pure tone being a result of a complex interaction on the basilar membrane of intermodulation distortion products.
Publisher: Wiley
Date: 08-1996
DOI: 10.1111/J.1440-1754.1996.TB02568.X
Abstract: To report a new case of de novo 7q deletion distal to q35. Developmental, cytogenetic and audiological investigations were carried out in the assessment of this rare chromosomal condition. Moderate developmental delay, mild congenital microcephaly, growth retardation and conductive hearing impairment were found for this case of 46,XX,del(7)(q35). The phenotype of 7q terminal deletion is highly variable.
Publisher: Author(s)
Date: 2018
DOI: 10.1063/1.5038493
Publisher: Acoustical Society of America (ASA)
Date: 2005
DOI: 10.1121/1.1798352
Abstract: In the guinea pig it has been shown that the nonlinear derived transient evoked otoacoustic emission (TEOAEnl) is comprised of significant amounts of intermodulation distortion energy. It is expected that intermodulation distortion arising from a nonlinear distortion mechanism will contribute to the overall TEOAE in a stimulus-level-dependent manner, being greatest when basilar-membrane vibration in response to a click stimulus is greatest with decay of vibration of the basilar membrane subsequent to stimulation by a click, nonlinear interaction along the cochlear partition should reduce and so provide for a linear mechanism to dominate TEOAEnl generation, i.e., the contributions of each of these mechanisms should be delay dependent. To examine this delay dependence, TEOAEnl evoked by acoustic clicks of varying bandwidth were time-domain windowed using a recursive exponential filter in an attempt to separate two components with litude and phase properties consistent with different mechanisms of OAE generation. It was found that the part of the TEOAEnl occurring first in time can have a relatively constant litude and shallow phase slope, consistent with a nonlinear distortion mechanism. The latter part of the TEOAEnl has an litude microstructure and a phase response more consistent with a place-fixed mechanism.
Publisher: Elsevier BV
Date: 02-2016
DOI: 10.1016/J.HEARES.2015.11.006
Abstract: Distortion product otoacoustic emissions (DPOAEs) were used to assess outer hair cell (OHC) integrity in human ears with age-related hearing loss. Sound pressure measurements were made in the ear canal over the stimulus range 40-90 dB SPL (L2), with L1 = 0.45*L2 + 44 with F2 = 2 and 3 or 4 kHz. Model-generated DPOAE I/O functions were fit to DPOAE data to quantify the contribution of loss of nonlinearity (OHC loss) to the hearing loss. Results suggest OHC loss as a contributing cause of age-related hearing, regardless of audiogram configuration. It seems likely that OHC and strial pathology co-exist in ears with AHL.
Publisher: Elsevier BV
Date: 09-2003
DOI: 10.1016/S0378-5955(03)00193-X
Abstract: Human stimulus-frequency otoacoustic emissions (SFOAEs) evoked by low-level stimuli have previously been shown to have properties consistent with such emissions arising from a linear place-fixed reflection mechanism with SFOAE microstructure thought to be due to a variation in the effective reflectance with position along the cochlea [Zweig and Shera, J. Acoust. Soc. Am. 98 (1995) 2018-2047]. Here we report SFOAEs in the guinea pig obtained using a nonlinear extraction paradigm from the ear-canal recording that show litude and phase microstructure akin to that seen in human SFOAEs. Inverse Fourier analysis of the SFOAE spectrum indicates that SFOAEs in the guinea pig are a stimulus level-dependent mix of OAEs arising from linear-reflection and nonlinear-distortion mechanisms. Although the SFOAEs are dominated by OAE generated by a linear-reflection mechanism at low and moderate stimulus levels, nonlinear distortion can dominate some part of, or all of, the emission spectrum at high levels. Amplitude and phase microstructure in the guinea pig SFOAE is evidently a construct of (i). the complex addition of nonlinear-distortion and linear-reflection components (ii). variation in the effective reflectance with position along the cochlea and perhaps (iii). the complex addition of multiple intra-cochlear reflections.
Publisher: Acoustical Society of America (ASA)
Date: 10-2014
DOI: 10.1121/1.4900343
Publisher: Elsevier BV
Date: 04-2018
Publisher: Acoustical Society of America (ASA)
Date: 10-2006
DOI: 10.1121/1.2338291
Abstract: The 2f1-f2 distortion product otoacoustic emission (DPOAE) is thought to arise primarily from the complex interaction of components that come from two different cochlear locations. Such distortion has its origin in the nonlinear interaction on the basilar membrane of the excitation patterns resulting from the two stimulus tones, f1 and f2. Here we examine the spatial extent of initial generation of the 2f1-f2 OAE by acoustically traumatizing the base of the cochlea and so eliminating the contribution of the basal region of the cochlea to the generation of 2f1-f2. Explicitly, litude-modulated, or continuously varying in level, stimulus tones with f2∕f1=1.2 and f2=8000–8940Hz were used to generate the 2f1-f2 DPOAE in guinea pig before and after acoustically traumatizing the basal region of the cochlea (the origin of any basal-to-f2 distortion product generators). It was found, based on correlation analysis, that there does not appear to be a basal-to-f2 distortion product generation mechanism contributing significantly to the guinea pig 2f1-f2 OAE up to L1=80dB sound pressure level (SPL).
Publisher: Acoustical Society of America (ASA)
Date: 07-1998
DOI: 10.1121/1.423292
Abstract: Otoacoustic emissions have historically been measured with an acoustical probe assembly hermetically sealed in the ear canal, imposing in most cases a limited stimulus bandwidth. A physically open recording system should afford the possibility of a greater stimulus bandwidth but the change in acoustical load may affect the magnitude of otoacoustic emissions obtained. Here it is reported that the authors have measured in the guinea pig transient-evoked otoacoustic emissions extending in frequency to 20 kHz and cubic distortion tone otoacoustic emissions for f2=4737 and 8096 Hz with a physically open sound system. To address the effect of acoustical load provided by a physically open versus hermetically sealed system, the authors compared the litude of electrically evoked otoacoustic emissions recorded from a guinea pig in each case. The change in acoustical load in the ear canal introduced by the change in recording setup did not appear to make a substantial difference to the magnitude of otoacoustic emissions measured. A physically open recording system provides a good alternative to traditional acoustical probe assemblies sealed in the ear canal for the laboratory measurement of acoustically evoked otoacoustic emissions, with the advantage of permitting a greater stimulus bandwidth.
Publisher: IOP Publishing
Date: 13-04-2018
Publisher: Elsevier BV
Date: 09-2005
DOI: 10.1016/J.HEARES.2005.04.005
Abstract: Otoacoustic emissions provide unambiguous evidence that the cochlea supports energy propagation both towards, and away from, the stapes. The standard wave model for energy transport and cochlear mechanical lification provides for compressional and inertial waves to transport this energy, the compressional wave through the fluids and the inertial wave along the basilar membrane via fluid coupling. It is generally accepted that energy propagation away from the stapes is dominated by a traveling wave mechanism along the basilar membrane. The mechanism by which energy is predominantly transported back to the stapes remains controversial. Here, we compared signal onset delay measurements and rise/steady-state/fall times for SFOAEs and 2f1-f2 OAEs (f2/f1=1.2) obtained using a pulsed-tone paradigm in guinea pig. Comparison of 2f1-f2 OAE signal onset delay for the OAE arising from the f2 region with SFOAE signal onset delay (matched to the f2 stimulus frequency) based on signal onset occurring at 10% of the peak signal litude was suggestive of a bi-directional traveling wave mechanism. However, significant variability in signal onset delay and signal rise, steady-state duration, and fall times for both the 2f1-f2 OAE and SFOAE was found, qualifying this interpretation. Such variability requires explanation, awaiting further studies.
Publisher: ASA
Date: 2010
DOI: 10.1121/1.3485676
Publisher: Elsevier BV
Date: 09-1998
DOI: 10.1016/S0378-5955(98)00100-2
Abstract: The basilar membrane (BM) input output (I/O) function is a non-linear compressive function over much of its operating range. A low level non-compressive region with a break-point or compression threshold between 20 and 40 dB SPL has been identified. To date, no similar compression threshold in cubic distortion tone otoacoustic emission (CDT) data, which would illustrate the dependence of the CDT on BM growth, has been demonstrated. A Taylor series expansion of the outer hair cell gating function yields an litude term for 2f1-f2 of p.A1(2).A2, where A1 and A2 are the displacement litudes of the BM for two pure tone input stimuli of levels L1 and L2, p a constant. By selectively varying either L1 or L2 with f2/f1 appropriately chosen to reduce suppression effects, the CDT I/O function can be examined for deviation from the power law. In particular, if the litude of the CDT were dependent on BM displacement litude, then it should be possible by an appropriate choice of parameters to measure compression threshold. We have examined CDT I/O functions for an f2 of 8 kHz in the guinea pig and found them to be consistent with the expected power law. With L1 held constant, L2 varied and f2/f1 = 1.6, a low level region with a slope of one and a compressive region with a slope of 0.14-0.27 corresponding to the analogous regions of the BM I/O function was identified, with a break-point or compression threshold of 22-33 dB SPL.
Publisher: Elsevier BV
Date: 2000
DOI: 10.1016/S0378-5955(99)00132-X
Abstract: Several studies have shown that acoustic trauma to the base of the cochlea can result in loss of transient-evoked otoacoustic emission (TEOAE) energy at frequencies much lower than those affected in the audiogram. We have extended these studies to show that the low-frequency emission energy was substantially affected if the transient stimulus included frequencies within the range affected by the trauma, otherwise the change observed was small. In keeping with the suggestion that TEOAEs are predominantly comprised of intermodulation distortion energy (Yates and Withnell, Hear. Res. 136 (1999) 49-64), trauma to the basal region of the cochlea was found to affect emission energy across a broad frequency range in response to a wide-band acoustic stimulus. Further, group delay measurements demonstrated that the dominant contribution to the TEOAE originated from the basal region of the cochlea.
Publisher: Acoustical Society of America (ASA)
Date: 02-1999
DOI: 10.1121/1.426280
Abstract: Recently, [J. Acoust. Soc. Am. 104, 344–349 (1998)] reported a pure tone acoustic enhancement of the transient-evoked otoacoustic emission (TEOAE). They state that their data conflict with the existing theory that the TEOAE represents a one-to-one frequency response to stimulus component frequencies. Therefore, they interpreted the observed enhancement as a result of a complex interaction on the basilar membrane of hypothetical intermodulation distortion products. This Letter reviews recent data and proposes an alternative interpretation that the enhancement results from an impedance discontinuity at the pure tone characteristic frequency (CF) location. TEOAEs at frequencies below this tone are reflected from its CF location rather than from their own CF locations.
Publisher: Elsevier BV
Date: 10-1999
DOI: 10.1016/S0378-5955(99)00108-2
Abstract: Transient-evoked otoacoustic emissions (TEOAEs) are low-intensity sounds recorded in the external ear canal immediately following stimulation by a transient stimulus, typically a click. While the details of their production is unknown, there is evidence to suggest that the litude of each component frequency reflects the physiological condition of the corresponding region of the cochlea. Certain observations are at variance with this assumption, however, suggesting that pathology at a basal site within the cochlea might affect the production of emissions at frequencies which are not characteristic for that site. We have recorded click-evoked emissions in guinea pigs using high-pass clicks and found emissions at frequencies which are not present in the stimulus and which could not, therefore, have originated from the characteristic place for those emission frequencies. These new frequencies are, by definition, intermodulation distortion frequencies and must have been generated from combinations of frequencies in the stimulus by non-linear processes within the cochlea. Further processing of the emissions by Kemp's technique of non-linear recovery showed that the magnitude of emissions at frequencies within the stimulus frequency pass-band was approximately the same as that of frequencies not present in the stimulus. We propose that, in guinea pigs at least, most of the click-evoked emission energy is generated as intermodulation distortion, produced by non-linear intermodulation between various frequency components of the stimulus. If this result is confirmed in humans, many of the anomalies in the literature may be resolved.
Publisher: Informa UK Limited
Date: 14-05-2014
DOI: 10.3109/14992027.2014.898122
Abstract: To assess the clinical utility of quantifying pure-tone hearing thresholds in terms of the forward-going sound pressure wave. Sound pressure measurements in the ear canal were used to derive, with hearing threshold measurements, hearing thresholds expressed in terms of the forward-going sound pressure wave, hearing thresholds based on coupler-based calibration, and hearing thresholds expressed in terms of the sound pressure measured at the microphone. Fifty-two adults, 18 to 34 years of age, served as the study group. Audiogram configurations were similar up to 2000 Hz for the three expressions of hearing threshold, consistent with the ear canal acting as a simple volume up to this frequency. Above 2000 Hz, notable differences in hearing threshold were found, consistent with the acoustic input impedance of the ear differing from a rigid, hard-walled cavity. Repeat testing showed all three expressions of hearing threshold to be repeatable. High density measurements of hearing threshold from 3000 to 6000 Hz provided qualified support for the derivation of the forward-going sound pressure wave. Hearing thresholds expressed in terms of the forward-going sound pressure wave are repeatable, and with in-situ calibration, may be superior to the current coupler-based method.
Publisher: Springer Science and Business Media LLC
Date: 06-08-2013
Publisher: WORLD SCIENTIFIC
Date: 08-2006
Publisher: Ovid Technologies (Wolters Kluwer Health)
Date: 10-2003
Publisher: AIP Publishing LLC
Date: 2015
DOI: 10.1063/1.4939367
Publisher: Public Library of Science (PLoS)
Date: 24-08-2021
DOI: 10.1371/JOURNAL.PONE.0255821
Abstract: As the resolution of 3D printing techniques improves, the possibility of in idualized, 3-ossicle constructions adds a new dimension to middle ear prostheses. In order to optimize these designs, it is essential to understand how the ossicles and ligaments work together to transmit sound, and thus how ligaments should be replicated in a middle ear reconstruction. The middle ear ligaments are thought to play a significant role in maintaining the position of the ossicles and constraining axis of rotation. Paradoxically, investigations of the role of ligaments to date have shown very little impact on middle ear sound transmission. We explored the role of the two attachments in the gerbil middle ear analogous to human ligaments, the posterior incudal ligament and the anterior mallear process, severing both attachments and measuring change in hearing sensitivity. The impact of severing the attachments on the position of the ossicular chain was visualized using synchrotron microtomography imaging of the middle ear. In contrast to previous studies, a threshold change on the order of 20 dB across a wide range of frequencies was found when both ligaments were severed. Concomitantly, a shift in position of the ossicles was observed from the x-ray imaging and 3D renderings of the ossicular chain. These findings contrast with previous studies, demonstrating that these ligaments play a significant role in the transmission of sound through the middle ear. It appears that both mallear and incudal ligaments must be severed in order to impair sound transmission. The results of this study have significance for middle ear reconstructive surgery and the design of 3D-printed three-ossicle biocompatible prostheses.
Publisher: Springer Science and Business Media LLC
Date: 12-04-2021
Publisher: WORLD SCIENTIFIC
Date: 02-2003
Start Date: 2008
End Date: 2009
Funder: U.S. Department of Health and Human Services
View Funded ActivityStart Date: 2016
End Date: 2017
Funder: Indiana University
View Funded Activity