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Alamri Y, Jennings SG. Computational modeling of the human compound action potential. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2023; 153:2376. [PMID: 37092943 PMCID: PMC10119875 DOI: 10.1121/10.0017863] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2022] [Revised: 03/21/2023] [Accepted: 04/04/2023] [Indexed: 05/03/2023]
Abstract
The auditory nerve (AN) compound action potential (CAP) is an important tool for assessing auditory disorders and monitoring the health of the auditory periphery during surgical procedures. The CAP has been mathematically conceptualized as the convolution of a unit response (UR) waveform with the firing rate of a population of AN fibers. Here, an approach for predicting experimentally recorded CAPs in humans is proposed, which involves the use of human-based computational models to simulate AN activity. CAPs elicited by clicks, chirps, and amplitude-modulated carriers were simulated and compared with empirically recorded CAPs from human subjects. In addition, narrowband CAPs derived from noise-masked clicks and tone bursts were simulated. Many morphological, temporal, and spectral aspects of human CAPs were captured by the simulations for all stimuli tested. These findings support the use of model simulations of the human CAP to refine existing human-based models of the auditory periphery, aid in the design and analysis of auditory experiments, and predict the effects of hearing loss, synaptopathy, and other auditory disorders on the human CAP.
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Affiliation(s)
- Yousef Alamri
- Department of Biomedical Engineering, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
| | - Skyler G Jennings
- Department of Communication Sciences and Disorders, The University of Utah, 390 South, 1530 East, BEHS 1201, Salt Lake City, Utah 84112, USA
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Naghibolhosseini M. The Effect of Stimuli Level on Distortion Product Otoacoustic Emission in Normal Hearing Adults. ACOUSTICS (BASEL, SWITZERLAND) 2023; 5:72-86. [PMID: 36815944 PMCID: PMC9930411 DOI: 10.3390/acoustics5010005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
The goal of this study is to compare three of the most commonly used primary-level relation paradigms (i.e., Scissors, Boys Town 'Optimal', and Equal-Level) in generation of distortion product otoacoustic emissions (DPOAEs) in normal hearing adults. The generator and reflection components were extracted from DPOAEs in each paradigm. The generator and reflection component levels and input/output (I/O) functions were compared across paradigms and primary-tone levels. The results showed a different I/O function growth behavior across frequency and levels among paradigms. The Optimal paradigm showed a systematic change in the generator and reflection component levels and I/O slopes across primary levels among subjects. Moreover, the levels and slopes in the Optimal paradigm were more distinct across levels with less variations across frequency leading to a systematic change in the DPOAE fine structure across levels. The I/O functions were found to be more sensitive to the selected paradigm; especially the I/O function for the reflection component. The I/O functions of the reflection components showed large variability across frequencies due to different frequency shifts in their microstructure depending on the paradigm. The findings of this study suggested the Optimal paradigm as the proper primary-level relation to study cochlear amplification/compression. The findings of this study shows that care needs to be taken in comparing the findings of different studies that generated DPOAEs with a different level-relation paradigm.
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Affiliation(s)
- Maryam Naghibolhosseini
- Department of Communicative Sciences and Disorders, Michigan State University, East Lansing, MI 48823, USA
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Abdala C, Luo P, Shera CA. Characterizing the Relationship Between Reflection and Distortion Otoacoustic Emissions in Normal-Hearing Adults. J Assoc Res Otolaryngol 2022; 23:647-664. [PMID: 35804277 PMCID: PMC9613820 DOI: 10.1007/s10162-022-00857-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Accepted: 06/24/2022] [Indexed: 11/28/2022] Open
Abstract
Otoacoustic emissions (OAEs) arise from one (or a combination) of two basic generation mechanisms in the cochlea: nonlinear distortion and linear reflection. As a result of having distinct generation processes, these two classes of emissions may provide non-redundant information about hair-cell integrity and show distinct sensitivities to cochlear pathology. Here, we characterize the relationship between reflection and distortion emissions in normal hearers across a broad frequency and stimulus-level space using novel analysis techniques. Furthermore, we illustrate the promise of this approach in a small group of individuals with mild-moderate hearing loss. A "joint-OAE profile" was created by measuring interleaved swept-tone stimulus-frequency OAEs (SFOAEs) and 2f1-f2 distortion-product OAEs (DPOAEs) in the same ears using well-considered parameters. OAE spectra and input/output functions were calculated across five octaves. Using our specific recording protocol and analysis scheme, SFOAEs in normal hearers had higher levels than did DPOAEs, with the most pronounced differences occurring at the highest stimulus levels. Also, SFOAE compression occurred at higher stimulus levels (than did DPOAE compression) and its growth in the compressed region was steeper. The diagnostic implications of these findings and the influence of the measurement protocol on both OAEs (and on their relationship) are discussed.
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Affiliation(s)
- Carolina Abdala
- Auditory Research Center, Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA, 90033, USA.
| | - Ping Luo
- Auditory Research Center, Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA, 90033, USA
| | - Christopher A Shera
- Auditory Research Center, Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA, 90033, USA
- Department of Physics and Astronomy, University of Southern California, Los Angeles, CA, 90089, USA
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Abstract
OBJECTIVE As humans age, compressive nonlinearity-a hallmark of healthy cochlear function-changes. The nonlinear distortion-component of the distortion product otoacoustic emission (DPOAE) provides a noninvasive gauge of cochlear nonlinearity. Earlier published work has suggested that weakened nonlinearity begins in middle age; the current work extends this investigation into the eight decade of life using advanced DPOAE data collection and analysis methods as well as multiple metrics of nonlinearity, including a test of loudness scaling. DESIGN The 2f1-f2 DPOAE was recorded in 20 young adults, 25 middle-aged adults and 32 older adults from f2 = 0.78 to 9.4 kHz with primary tones (f2/f1 = 1.22) swept upward at a rate of 0.5 octave/sec. Only frequencies with audiometric thresholds ≤20 dB HL were included in the analysis and to the extent possible, ears were audiometrically matched to eliminate hearing threshold as a contributing factor to the observed age effects. Input/output functions were generated for the separated distortion-component of the DPOAE to probe compressive nonlinearity of the cochlea, and ipsilateral suppression of the DPOAE was conducted to probe two-tone suppression. To investigate the perceptual effects of weakening nonlinearity on loudness perception, the same subjects performed categorical loudness scaling. Age effects on both DPOAE and loudness scaling variables were assessed, and correlations were conducted between key OAE and perceptual metrics. RESULTS Age × Frequency ANOVAs revealed that the compression knee of the DPOAE I/O function occurred at higher stimulus levels in both groups of older adults compared to young adults, suggesting an expanded linear range with aging; also, the compressive slope (growth beyond the knee point) was steeper in older-adults compared to young adults. These results were most notable at high frequencies. ANOVAs including age and auditory threshold as factors confirmed that the age effect observed was independent of threshold. Additionally, in smaller subsets of subjects with audiometrically matched data, these same trends persisted, further ruling out hearing threshold as an influential factor. The growth of DPOAE ipsilateral suppression was shallower near 4 kHz in middle-aged and older adults compared to young adults and elevated suppression thresholds were observed. Results of categorical loudness scaling showed steeper growth of loudness for older adults and, at fixed sensation levels (dB SL), the older-adult group rated tones as louder than did their young-adult counterparts, suggesting abnormal loudness growth and perception. Several correlations between the compression knee of the DPOAE I/O function and key metrics of loudness scaling were significant and accounted for up to one-third of the variance. CONCLUSIONS Results indicate that the aging cochlea begins to show weakened nonlinearity in middle age and it progressively weakens further into senescence. The perceptual impact of weakened nonlinearity during aging is manifested as abnormal loudness judgments; that is, in older-adult ears, a tone considered comfortable or medium in young-adult ears can be considered loud. The biophysical origin of this weakened nonlinearity is not known. It is hypothesized to reflect aging-related damage to, or loss of, outer hair cells and their stereocilia. More work is warranted to better define the perceptual impact of a linearized cochlear response in older adults and to consider how this deficit might impact the fitting of hearing aids and other intervention strategies.
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Encina-Llamas G, Dau T, Epp B. On the use of envelope following responses to estimate peripheral level compression in the auditory system. Sci Rep 2021; 11:6962. [PMID: 33772043 PMCID: PMC7997911 DOI: 10.1038/s41598-021-85850-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 03/08/2021] [Indexed: 12/22/2022] Open
Abstract
Individual estimates of cochlear compression may provide complementary information to traditional audiometric hearing thresholds in disentangling different types of peripheral cochlear damage. Here we investigated the use of the slope of envelope following response (EFR) magnitude-level functions obtained from four simultaneously presented amplitude modulated tones with modulation frequencies of 80-100 Hz as a proxy of peripheral level compression. Compression estimates in individual normal hearing (NH) listeners were consistent with previously reported group-averaged compression estimates based on psychoacoustical and distortion-product oto-acoustic emission (DPOAE) measures in human listeners. They were also similar to basilar membrane (BM) compression values measured invasively in non-human mammals. EFR-based compression estimates in hearing-impaired listeners were less compressive than those for the NH listeners, consistent with a reduction of BM compression. Cochlear compression was also estimated using DPOAEs in the same NH listeners. DPOAE estimates were larger (less compressive) than EFRs estimates, showing no correlation. Despite the numerical concordance between EFR-based compression estimates and group-averaged estimates from other methods, simulations using an auditory nerve (AN) model revealed that compression estimates based on EFRs might be highly influenced by contributions from off-characteristic frequency (CF) neural populations. This compromises the possibility to estimate on-CF (i.e., frequency-specific or "local") peripheral level compression with EFRs.
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Affiliation(s)
- Gerard Encina-Llamas
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark (DTU), 2800, Kongens Lyngby, Denmark.
| | - Torsten Dau
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark (DTU), 2800, Kongens Lyngby, Denmark
| | - Bastian Epp
- Hearing Systems Section, Department of Health Technology, Technical University of Denmark (DTU), 2800, Kongens Lyngby, Denmark
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Brainstem correlates of cochlear nonlinearity measured via the scalp-recorded frequency-following response. Neuroreport 2020; 31:702-707. [PMID: 32453027 DOI: 10.1097/wnr.0000000000001452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
The frequency-following response (FFR) is an EEG-based potential used to characterize the brainstem encoding of complex sounds. Adopting techniques from auditory signal processing, we assessed the degree to which FFRs encode important properties of cochlear processing (e.g. nonlinearities) and their relation to speech-in-noise (SIN) listening skills. Based on the premise that normal cochlear transduction is characterized by rectification and compression, we reasoned these nonlinearities would create measurable harmonic distortion in FFRs in response to even pure tone input. We recorded FFRs to nonspeech (pure- and amplitude-modulated-tones) stimuli in normal-hearing individuals. We then compared conventional indices of cochlear nonlinearity, via distortion product otoacoustic emission (DPOAE) I/O functions, to total harmonic distortion measured from neural FFRs (FFRTHD). Analysis of DPOAE growth and the FFRTHD revealed listeners with higher cochlear compression thresholds had lower neural FFRTHD distortion (i.e. more linear FFRs), thus linking cochlear and brainstem correlates of auditory nonlinearity. Importantly, FFRTHD was also negatively correlated with SIN perception whereby listeners with higher FFRTHD (i.e. more nonlinear responses) showed better performance on the QuickSIN. We infer individual differences in SIN perception and FFR nonlinearity even in normal-hearing individuals may reflect subtle differences in auditory health and suprathreshold hearing skills not captured by normal audiometric evaluation. Future studies in hearing-impaired individuals and animal models are necessary to confirm the diagnostic utility of FFRTHD and its relation to cochlear hearing loss or peripheral neurodegeneration in humans.
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Garrett M, Verhulst S. Applicability of subcortical EEG metrics of synaptopathy to older listeners with impaired audiograms. Hear Res 2019; 380:150-165. [DOI: 10.1016/j.heares.2019.07.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2018] [Revised: 06/24/2019] [Accepted: 07/01/2019] [Indexed: 01/12/2023]
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Garrett M, Debener S, Verhulst S. Acquisition of Subcortical Auditory Potentials With Around-the-Ear cEEGrid Technology in Normal and Hearing Impaired Listeners. Front Neurosci 2019; 13:730. [PMID: 31379484 PMCID: PMC6646709 DOI: 10.3389/fnins.2019.00730] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2019] [Accepted: 07/01/2019] [Indexed: 11/29/2022] Open
Abstract
Even though the principles of recording brain electrical activity remain unchanged since their discovery, their acquisition has seen major improvements. The cEEGrid, a recently developed flex-printed multi-channel sensory array, can be placed around the ear and successfully record well-known cortical electrophysiological potentials such as late auditory evoked potentials (AEPs) or the P300. Due to its fast and easy application as well as its long-lasting signal recording window, the cEEGrid technology offers great potential as a flexible and ‘wearable’ solution for the acquisition of neural correlates of hearing. Early potentials of auditory processing such as the auditory brainstem response (ABR) are already used in clinical assessment of sensorineural hearing disorders and envelope following responses (EFR) have shown promising results in the diagnosis of suprathreshold hearing deficits. This study evaluates the suitability of the cEEGrid electrode configuration to capture these AEPs. cEEGrid potentials were recorded and compared to cap-EEG potentials for young normal-hearing listeners and older listeners with high-frequency sloping audiograms to assess whether the recordings are adequately sensitive for hearing diagnostics. ABRs were elicited by presenting clicks (70 and 100-dB peSPL) and stimulation for the EFRs consisted of 120 Hz amplitude-modulated white noise carriers presented at 70-dB SPL. Data from nine bipolar cEEGrid channels and one classical cap-EEG montage (earlobes to vertex) were analysed and outcome measures were compared. Results show that the cEEGrid is able to record ABRs and EFRs with comparable shape to those recorded using a conventional cap-EEG recording montage and the same amplifier. Signal strength is lower but can still produce responses above the individual neural electrophysiological noise floor. This study shows that the application of the cEEGrid can be extended to the acquisition of early auditory evoked potentials.
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Affiliation(s)
- Markus Garrett
- Department of Medical Physics and Acoustics, University of Oldenburg, Oldenburg, Germany.,Cluster of Excellence "Hearing4all", Oldenburg, Germany
| | - Stefan Debener
- Cluster of Excellence "Hearing4all", Oldenburg, Germany.,Neuropsychology Laboratory, Department of Psychology, University of Oldenburg, Oldenburg, Germany
| | - Sarah Verhulst
- Department of Information Technology, Hearing Technology @ WAVES, Ghent University, Ghent, Belgium
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Changes in the Compressive Nonlinearity of the Cochlea During Early Aging: Estimates From Distortion OAE Input/Output Functions. Ear Hear 2018; 37:603-14. [PMID: 27232070 DOI: 10.1097/aud.0000000000000319] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The level-dependent growth of distortion product otoacoustic emissions (DPOAEs) provides an indirect metric of cochlear compressive nonlinearity. Recent evidence suggests that aging reduces nonlinear distortion emissions more than those associated with linear reflection. Therefore, in this study, we generate input/output (I/O) functions from the isolated distortion component of the DPOAE to probe the effects of early aging on the compressive nonlinearity of the cochlea. DESIGN Thirty adults whose ages ranged from 18 to 64 years participated in this study, forming a continuum of young to middle-age subjects. When necessary for analyses, subjects were divided into a young-adult group with a mean age of 21 years, and a middle-aged group with a mean age of 52 years. All young-adult subjects and 11 of the middle-aged subjects had normal hearing; 4 middle-aged ears had slight audiometric threshold elevation at mid-to-high frequencies. DPOAEs (2f1 - f2) were recorded using primary tones swept upward in frequency from 0.5 to 8 kHz, and varied from 25 to 80 dB sound pressure level. The nonlinear distortion component of the total DPOAE was separated and used to create I/O functions at one-half octave intervals from 1.3 to 7.4 kHz. Four features of OAE compression were extracted from a fit to these functions: compression threshold, range of compression, compression slope, and low-level growth. These values were compared between age groups and correlational analyses were conducted between OAE compression threshold and age with audiometric threshold controlled. RESULTS Older ears had reduced DPOAE amplitude compared with young-adult ears. The OAE compression threshold was elevated at test frequencies above 2 kHz in the middle-aged subjects by 19 dB (35 versus 54 dB SPL), thereby reducing the compression range. In addition, middle-aged ears showed steeper amplitude growth beyond the compression threshold. Audiometric threshold was initially found to be a confound in establishing the relationship between compression and age; however, statistical analyses allowed us to control its variance. Correlations performed while controlling for age differences in high-frequency audiometric thresholds showed significant relationships between the DPOAE I/O compression threshold and age: Older subjects tended to have elevated compression thresholds compared with younger subjects and an extended range of monotonic growth. CONCLUSIONS Cochlear manifestations of nonlinearity, such as the DPOAE, weaken during early aging, and DPOAE I/O functions become linearized. Commensurate changes in high-frequency audiometric thresholds are not sufficient to fully explain these changes. The results suggest that age-related changes in compressive nonlinearity could produce a reduced dynamic range of hearing, and contribute to perceptual difficulties in older listeners.
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Neely ST, Rasetshwane DM. Modeling signal propagation in the human cochlea. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:2155. [PMID: 29092611 PMCID: PMC6578578 DOI: 10.1121/1.5007719] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2017] [Revised: 09/28/2017] [Accepted: 09/29/2017] [Indexed: 05/31/2023]
Abstract
The level-dependent component of the latency of human auditory brainstem responses (ABR) to tonebursts decreases by about 38% for every 20-dB increase in stimulus level over a wide range of both frequency and level [Neely, Norton, Gorga, and Jesteadt (1998). J. Acoust. Soc. Am. 31, 87-97]. This level-dependence has now been simulated in an active, nonlinear, transmission-line model of cochlear mechanics combined with an adaptation stage. The micromechanics in this model are similar to previous models except that a dual role is proposed for the tectorial membrane (TM): (1) passive sharpening the tuning of sensory-cell inputs (relative to basilar-membrane vibrations) and (2) providing an optimal phase shift (relative to basilar-membrane vibrations) of outer-hair-cell feedback forces, so that amplification is restricted to a limited range of frequencies. The adaptation stage, which represents synaptic adaptation of neural signals, contributes to the latency level-dependence more at low frequencies than at high frequencies. Compression in this model spans the range of audible sound levels with a compression ratio of about 2:1. With further development, the proposed model of cochlear micromechanics could be useful both (1) as a front-end to functional models of the auditory system and (2) as a foundation for understanding the physiological basis of cochlear amplification.
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Affiliation(s)
- Stephen T Neely
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA
| | - Daniel M Rasetshwane
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA
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11
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Abdala C, Kalluri R. Towards a joint reflection-distortion otoacoustic emission profile: Results in normal and impaired ears. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:812. [PMID: 28863614 PMCID: PMC5552396 DOI: 10.1121/1.4996859] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/24/2017] [Revised: 07/14/2017] [Accepted: 07/17/2017] [Indexed: 05/12/2023]
Abstract
Otoacoustic emissions (OAEs) provide salient information about cochlear function and dysfunction. Two broad classes of emissions, linear reflection and nonlinear distortion, arise via distinct cochlear processes and hence, appear to provide independent information about cochlear health and hearing. Considered in combination, these two OAE types may characterize sensory hearing loss most effectively. In this study, the level-dependent growth of stimulus-frequency OAEs (a reflection-type emission) and distortion-product OAEs (a distortion-type emission) were measured in ten normal-hearing ears and eight ears with slight-to-moderate sensorineural hearing loss. Metrics of OAE strength and compression were derived from OAE input/output functions and then considered in a combined fashion. Results indicate that SFOAEs and DPOAEs differ significantly in their strength and compression features. When SFOAE and DPOAE metrics are displayed together on a two-dimensional plot, relatively well-defined data clusters describe their normative relationship. In hearing-impaired ears, this relationship is disrupted but not in a uniform way across ears; ears with similar audiograms showed differently altered joint-OAE profiles. Hearing loss sometimes affected only one OAE or one more than the other. Results suggest a joint-OAE profile is promising and warrants study in a large group of subjects with sensory hearing loss of varied etiologies.
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Affiliation(s)
- Carolina Abdala
- Caruso Department of Otolaryngology, Auditory Research Center, University of Southern California, 1640 Marengo Street, Suite 326, Los Angeles, California 90033, USA
| | - Radha Kalluri
- Caruso Department of Otolaryngology, Auditory Research Center, University of Southern California, 1640 Marengo Street, Suite 326, Los Angeles, California 90033, USA
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12
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Elliott SJ, Ni G, Sun L. Fitting pole-zero micromechanical models to cochlear response measurements. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:666. [PMID: 28863604 DOI: 10.1121/1.4996128] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
An efficient way of describing the linear micromechanical response of the cochlea is in terms of its poles and zeros. Pole-zero models with local scaling symmetry are derived for both one and two degree-of-freedom micromechanical systems. These elements are then used in a model of the coupled cochlea, which is optimised to minimise the mean square difference between its frequency response and that measured on the basilar membrane inside the mouse cochlea by Lee, Raphael, Xia, Kim, Grillet, Applegate, Ellerbee Bowden, and Oghalai [(2016) J. Neurosci. 36, 8160-8173] and Oghalai Lab [(2015). https://oghalailab.stanford.edu], at different excitation levels. A model with two degree-of-freedom micromechanics generally fits the measurements better than a model with single degree-of-freedom micromechanics, particularly at low excitations where the cochlea is active, except post-mortem conditions, when the cochlea is passive. The model with the best overall fit to the data is found to be one with two degree-of-freedom micromechanics and 3D fluid coupling. Although a unique lumped parameter network cannot be inferred from such a pole-zero description, these fitted results help indicate what properties such a network should have.
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Affiliation(s)
- Stephen J Elliott
- Institute of Sound and Vibration Research, University of Southampton, Highfield Campus, Southampton SO17 1BJ, United Kingdom
| | - Guangjian Ni
- Laboratory of Neural Engineering and Rehabilitation, Department of Biomedical Engineering, College of Precision Instruments and Optoelectronics Engineering and Tianjin International Joint Research Center for Neural Engineering and Academy of Medical Engineering and Translational Medicine, Tianjin University, Tianjin 300072, China
| | - Luyang Sun
- Key Laboratory of Noise and Vibration Research, Institute of Acoustics, Chinese Academy of Sciences, Beijing 100190, China
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Van Eeckhoutte M, Wouters J, Francart T. Auditory steady-state responses as neural correlates of loudness growth. Hear Res 2016; 342:58-68. [DOI: 10.1016/j.heares.2016.09.009] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2016] [Revised: 09/21/2016] [Accepted: 09/28/2016] [Indexed: 10/20/2022]
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14
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Verhulst S, Jagadeesh A, Mauermann M, Ernst F. Individual Differences in Auditory Brainstem Response Wave Characteristics: Relations to Different Aspects of Peripheral Hearing Loss. Trends Hear 2016; 20:2331216516672186. [PMID: 27837052 PMCID: PMC5117250 DOI: 10.1177/2331216516672186] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 09/08/2016] [Indexed: 11/20/2022] Open
Abstract
Little is known about how outer hair cell loss interacts with noise-induced and age-related auditory nerve degradation (i.e., cochlear synaptopathy) to affect auditory brainstem response (ABR) wave characteristics. Given that listeners with impaired audiograms likely suffer from mixtures of these hearing deficits and that ABR amplitudes have successfully been used to isolate synaptopathy in listeners with normal audiograms, an improved understanding of how different hearing pathologies affect the ABR source generators will improve their sensitivity in hearing diagnostics. We employed a functional model for human ABRs in which different combinations of hearing deficits were simulated and show that high-frequency cochlear gain loss steepens the slope of the ABR Wave-V latency versus intensity and amplitude versus intensity curves. We propose that grouping listeners according to a ratio of these slope metrics (i.e., the ABR growth ratio) might offer a way to factor out the outer hair cell loss deficit and maximally relate individual differences for constant ratios to other peripheral hearing deficits such as cochlear synaptopathy. We compared the model predictions to recorded click-ABRs from 30 participants with normal or high-frequency sloping audiograms and confirm the predicted relationship between the ABR latency growth curve and audiogram slope. Experimental ABR amplitude growth showed large individual differences and was compared with the Wave-I amplitude, Wave-V/I ratio, or the interwaveI-W latency in the same listeners. The model simulations along with the ABR recordings suggest that a hearing loss profile depicting the ABR growth ratio versus the Wave-I amplitude or Wave-V/I ratio might be able to differentiate outer hair cell deficits from cochlear synaptopathy in listeners with mixed pathologies.
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Affiliation(s)
- Sarah Verhulst
- Cluster of Excellence Hearing4all and Medizinische Physik, Department of Medical Physics and Acoustics, Oldenburg University, Oldenburg, Germany
- Department of Information Technology, Ghent University, Technologiepark, Zwijnaarde, Belgium
| | - Anoop Jagadeesh
- Cluster of Excellence Hearing4all and Medizinische Physik, Department of Medical Physics and Acoustics, Oldenburg University, Oldenburg, Germany
| | - Manfred Mauermann
- Cluster of Excellence Hearing4all and Medizinische Physik, Department of Medical Physics and Acoustics, Oldenburg University, Oldenburg, Germany
| | - Frauke Ernst
- Cluster of Excellence Hearing4all and Medizinische Physik, Department of Medical Physics and Acoustics, Oldenburg University, Oldenburg, Germany
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Rönnberg J, Lunner T, Ng EHN, Lidestam B, Zekveld AA, Sörqvist P, Lyxell B, Träff U, Yumba W, Classon E, Hällgren M, Larsby B, Signoret C, Pichora-Fuller MK, Rudner M, Danielsson H, Stenfelt S. Hearing impairment, cognition and speech understanding: exploratory factor analyses of a comprehensive test battery for a group of hearing aid users, the n200 study. Int J Audiol 2016; 55:623-42. [PMID: 27589015 PMCID: PMC5044772 DOI: 10.1080/14992027.2016.1219775] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2016] [Revised: 07/29/2016] [Accepted: 07/29/2016] [Indexed: 02/08/2023]
Abstract
OBJECTIVE The aims of the current n200 study were to assess the structural relations between three classes of test variables (i.e. HEARING, COGNITION and aided speech-in-noise OUTCOMES) and to describe the theoretical implications of these relations for the Ease of Language Understanding (ELU) model. STUDY SAMPLE Participants were 200 hard-of-hearing hearing-aid users, with a mean age of 60.8 years. Forty-three percent were females and the mean hearing threshold in the better ear was 37.4 dB HL. DESIGN LEVEL1 factor analyses extracted one factor per test and/or cognitive function based on a priori conceptualizations. The more abstract LEVEL 2 factor analyses were performed separately for the three classes of test variables. RESULTS The HEARING test variables resulted in two LEVEL 2 factors, which we labelled SENSITIVITY and TEMPORAL FINE STRUCTURE; the COGNITIVE variables in one COGNITION factor only, and OUTCOMES in two factors, NO CONTEXT and CONTEXT. COGNITION predicted the NO CONTEXT factor to a stronger extent than the CONTEXT outcome factor. TEMPORAL FINE STRUCTURE and SENSITIVITY were associated with COGNITION and all three contributed significantly and independently to especially the NO CONTEXT outcome scores (R(2) = 0.40). CONCLUSIONS All LEVEL 2 factors are important theoretically as well as for clinical assessment.
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Affiliation(s)
- Jerker Rönnberg
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Thomas Lunner
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Clinical and Experimental Medicine, Linköping University,
Linköping,
Sweden
- Eriksholm Research Centre,
Oticon A/S, Rørtangvej 20, 3070 Snekkersten,
Denmark
| | - Elaine Hoi Ning Ng
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Björn Lidestam
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
| | - Adriana Agatha Zekveld
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Section Ear & Hearing, Dept. of Otolaryngology-Head and Neck Surgery and EMGO Institute, VU University Medical Center,
Amsterdam,
The Netherlands
| | - Patrik Sörqvist
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Building, Energy and Environmental Engineering, University of Gävle,
Gävle,
Sweden
| | - Björn Lyxell
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Ulf Träff
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
| | - Wycliffe Yumba
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Elisabet Classon
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Mathias Hällgren
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Clinical and Experimental Medicine, Linköping University,
Linköping,
Sweden
| | - Birgitta Larsby
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Clinical and Experimental Medicine, Linköping University,
Linköping,
Sweden
| | - Carine Signoret
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - M. Kathleen Pichora-Fuller
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Psychology, University of Toronto,
Toronto,
Ontario,
Canada
- The Toronto Rehabilitation Institute, University Health Network,
Toronto,
Ontario,
Canada
- The Rotman Research Institute, Baycrest Hospital,
Toronto,
Ontario,
Canada
| | - Mary Rudner
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Henrik Danielsson
- Department of Behavioural Sciences and Learning, Linköping University,
Linköping,
Sweden
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
| | - Stefan Stenfelt
- Linnaeus Centre HEAD, Swedish Institute for Disability Research, Linköping University,
Linköping,
Sweden
- Department of Clinical and Experimental Medicine, Linköping University,
Linköping,
Sweden
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16
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Pieper I, Mauermann M, Kollmeier B, Ewert SD. Physiological motivated transmission-lines as front end for loudness models. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 139:2896. [PMID: 27250182 DOI: 10.1121/1.4949540] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The perception of loudness is strongly influenced by peripheral auditory processing, which calls for a physiologically correct peripheral auditory processing stage when constructing advanced loudness models. Most loudness models, however, rather follow a functional approach: a parallel auditory filter bank combined with a compression stage, followed by spectral and temporal integration. Such classical loudness models do not allow to directly link physiological measurements like otoacoustic emissions to properties of their auditory filterbank. However, this can be achieved with physiologically motivated transmission-line models (TLMs) of the cochlea. Here two active and nonlinear TLMs were tested as the peripheral front end of a loudness model. The TLMs are followed by a simple generic back end which performs integration of basilar-membrane "excitation" across place and time to yield a loudness estimate. The proposed model approach reaches similar performance as other state-of-the-art loudness models regarding the prediction of loudness in sones, equal-loudness contours (including spectral fine structure), and loudness as a function of bandwidth. The suggested model provides a powerful tool to directly connect objective measures of basilar membrane compression, such as distortion product otoacoustic emissions, and loudness in future studies.
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Affiliation(s)
- Iko Pieper
- Medizinische Physik and Cluster of Excellence Hearing4All, Universität Oldenburg, D-26111 Oldenburg, Germany
| | - Manfred Mauermann
- Medizinische Physik and Cluster of Excellence Hearing4All, Universität Oldenburg, D-26111 Oldenburg, Germany
| | - Birger Kollmeier
- Medizinische Physik and Cluster of Excellence Hearing4All, Universität Oldenburg, D-26111 Oldenburg, Germany
| | - Stephan D Ewert
- Medizinische Physik and Cluster of Excellence Hearing4All, Universität Oldenburg, D-26111 Oldenburg, Germany
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17
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Joshi SN, Wróblewski M, Schmid KK, Jesteadt W. Effects of relative and absolute frequency in the spectral weighting of loudness. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2016; 139:373-383. [PMID: 26827032 PMCID: PMC4723418 DOI: 10.1121/1.4939893] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 12/18/2015] [Accepted: 12/30/2015] [Indexed: 06/05/2023]
Abstract
The loudness of broadband sound is often modeled as a linear sum of specific loudness across frequency bands. In contrast, recent studies using molecular psychophysical methods suggest that low and high frequency components contribute more to the overall loudness than mid frequencies. In a series of experiments, the contribution of individual components to the overall loudness of a tone complex was assessed using the molecular psychophysical method as well as a loudness matching task. The stimuli were two spectrally overlapping ten-tone complexes with two equivalent rectangular bandwidth spacing between the tones, making it possible to separate effects of relative and absolute frequency. The lowest frequency components of the "low-frequency" and the "high-frequency" complexes were 208 and 808 Hz, respectively. Perceptual-weights data showed emphasis on lowest and highest frequencies of both the complexes, suggesting spectral-edge related effects. Loudness matching data in the same listeners confirmed the greater contribution of low and high frequency components to the overall loudness of the ten-tone complexes. Masked detection thresholds of the individual components within the tone complex were not correlated with perceptual weights. The results show that perceptual weights provide reliable behavioral correlates of relative contributions of the individual frequency components to overall loudness of broadband sounds.
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Affiliation(s)
- Suyash Narendra Joshi
- Center for Hearing Research, Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Marcin Wróblewski
- Center for Hearing Research, Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
| | - Kendra K Schmid
- Department of Biostatistics, College of Public Health, University of Nebraska Medical Center, Omaha, Nebraska 68198, USA
| | - Walt Jesteadt
- Center for Hearing Research, Boys Town National Research Hospital, Omaha, Nebraska 68131, USA
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18
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Influence of ketamine-xylazine anaesthesia on cubic and quadratic high-frequency distortion-product otoacoustic emissions. J Assoc Res Otolaryngol 2014; 15:695-705. [PMID: 25070925 DOI: 10.1007/s10162-014-0470-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Accepted: 05/28/2014] [Indexed: 01/13/2023] Open
Abstract
Ketamine is a dissociative anaesthetic, analgesic drug as well as an N-methyl-D-aspartate receptor antagonist and has been reported to influence otoacoustic emission amplitudes. In the present study, we assess the effect of ketamine-xylazine on high-frequency distortion-product otoacoustic emissions (DPOAE) in the bat species Carollia perspicillata, which serves as model for sensitive high-frequency hearing. Cubic DPOAE provide information about the nonlinear gain of the cochlear amplifier, whereas quadratic DPOAE are used to assess the symmetry of cochlear amplification and potential efferent influence on the operating state of the cochlear amplifier. During anaesthesia, maximum cubic DPOAE levels can increase by up to 35 dB within a medium stimulus level range from 35 to 60 dB SPL. Close to the -10 dB SPL threshold, at stimulus levels below about 20-30 dB SPL, anaesthesia reduces cubic DPOAE amplitudes and raises cubic DPOAE thresholds. This makes DPOAE growth functions steeper. Additionally, ketamine increases the optimum stimulus frequency ratio which is indicative of a reduction of cochlear tuning sharpness. The effect of ketamine on cubic DPOAE thresholds becomes stronger at higher stimulus frequencies and is highly significant for f2 frequencies above 40 kHz. Quadratic DPOAE levels are increased by up to 25 dB by ketamine at medium stimulus levels. In contrast to cubic DPOAEs, quadratic DPOAE threshold changes are variable and there is no significant loss of sensitivity during anaesthesia. We discuss that ketamine effects could be caused by modulation of middle ear function or a release from ipsilateral efferent modulation that mainly affects the gain of cochlear amplification.
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19
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Bharadwaj HM, Verhulst S, Shaheen L, Liberman MC, Shinn-Cunningham BG. Cochlear neuropathy and the coding of supra-threshold sound. Front Syst Neurosci 2014; 8:26. [PMID: 24600357 PMCID: PMC3930880 DOI: 10.3389/fnsys.2014.00026] [Citation(s) in RCA: 185] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2013] [Accepted: 02/05/2014] [Indexed: 11/13/2022] Open
Abstract
Many listeners with hearing thresholds within the clinically normal range nonetheless complain of difficulty hearing in everyday settings and understanding speech in noise. Converging evidence from human and animal studies points to one potential source of such difficulties: differences in the fidelity with which supra-threshold sound is encoded in the early portions of the auditory pathway. Measures of auditory subcortical steady-state responses (SSSRs) in humans and animals support the idea that the temporal precision of the early auditory representation can be poor even when hearing thresholds are normal. In humans with normal hearing thresholds (NHTs), paradigms that require listeners to make use of the detailed spectro-temporal structure of supra-threshold sound, such as selective attention and discrimination of frequency modulation (FM), reveal individual differences that correlate with subcortical temporal coding precision. Animal studies show that noise exposure and aging can cause a loss of a large percentage of auditory nerve fibers (ANFs) without any significant change in measured audiograms. Here, we argue that cochlear neuropathy may reduce encoding precision of supra-threshold sound, and that this manifests both behaviorally and in SSSRs in humans. Furthermore, recent studies suggest that noise-induced neuropathy may be selective for higher-threshold, lower-spontaneous-rate nerve fibers. Based on our hypothesis, we suggest some approaches that may yield particularly sensitive, objective measures of supra-threshold coding deficits that arise due to neuropathy. Finally, we comment on the potential clinical significance of these ideas and identify areas for future investigation.
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Affiliation(s)
- Hari M Bharadwaj
- Center for Computational Neuroscience and Neural Technology, Boston University Boston, MA, USA ; Department of Biomedical Engineering, Boston University Boston, MA, USA
| | - Sarah Verhulst
- Center for Computational Neuroscience and Neural Technology, Boston University Boston, MA, USA ; Department of Otology and Laryngology, Harvard Medical School Boston, MA, USA
| | - Luke Shaheen
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary Boston, MA, USA ; Harvard-MIT Division of Health Sciences and Technology, Speech and Hearing Bioscience and Technology Program Cambridge, MA, USA
| | - M Charles Liberman
- Department of Otology and Laryngology, Harvard Medical School Boston, MA, USA ; Eaton-Peabody Laboratories, Massachusetts Eye and Ear Infirmary Boston, MA, USA ; Harvard-MIT Division of Health Sciences and Technology, Speech and Hearing Bioscience and Technology Program Cambridge, MA, USA
| | - Barbara G Shinn-Cunningham
- Center for Computational Neuroscience and Neural Technology, Boston University Boston, MA, USA ; Department of Biomedical Engineering, Boston University Boston, MA, USA
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20
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Rasetshwane DM, Neely ST, Kopun JG, Gorga MP. Relation of distortion-product otoacoustic emission input-output functions to loudness. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 134:369-83. [PMID: 23862814 PMCID: PMC3724751 DOI: 10.1121/1.4807560] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2012] [Revised: 03/21/2013] [Accepted: 04/26/2013] [Indexed: 05/25/2023]
Abstract
The aim of this study is to further explore the relationship between distortion-product otoacoustic emission (DPOAE) measurements and categorical loudness scaling (CLS) measurements using multiple linear regression (MLR) analysis. Recently, Thorson et al. [J. Acoust. Soc. Am. 131, 1282-1295 (2012)] obtained predictions of CLS loudness ratings from DPOAE input/output (I/O) functions using MLR analysis. The present study extends that work by (1) considering two different (and potentially improved) MLR models, one for predicting loudness rating at specified input level and the other for predicting the input level for each loudness category and (2) validating the new models' predictions using an independent set of data. Strong correlations were obtained between predicted and measured data during the validation process with overall root-mean-square errors in the range 10.43-16.78 dB for the prediction of CLS input level, supporting the view that DPOAE I/O measurements can predict CLS loudness ratings and input levels, and thus may be useful for fitting hearing aids.
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Affiliation(s)
- Daniel M Rasetshwane
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
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21
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Thorson MJ, Kopun JG, Neely ST, Tan H, Gorga MP. Reliability of distortion-product otoacoustic emissions and their relation to loudness. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2012; 131:1282-95. [PMID: 22352502 PMCID: PMC3292604 DOI: 10.1121/1.3672654] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 11/17/2011] [Accepted: 11/17/2011] [Indexed: 05/25/2023]
Abstract
The reliability of distortion-product otoacoustic emission (DPOAE) measurements and their relation to loudness measurements was examined in 16 normal-hearing subjects and 58 subjects with hearing loss. The level of the distortion product (L(d)) was compared across two sessions and resulted in correlations that exceeded 0.90. The reliability of DPOAEs was less when parameters from nonlinear fits to the input/output (I/O) functions were compared across visits. Next, the relationship between DPOAE I/O parameters and the slope of the low-level portion of the categorical loudness scaling (CLS) function (soft slope) was assessed. Correlations of 0.65, 0.74, and 0.81 at 1, 2, and 4 kHz were observed between CLS soft slope and combined DPOAE parameters. Behavioral threshold had correlations of 0.82, 0.83, and 0.88 at 1, 2, and 4 kHz with CLS soft slope. Combining DPOAEs and behavioral threshold provided little additional information. Lastly, a multivariate approach utilizing the entire DPOAE I/O function was used to predict the CLS rating for each input level (dB SPL). Standard error of the estimate when using this method ranged from 2.4 to 3.0 categorical units (CU), suggesting that DPOAE I/O functions can predict CLS measures within the CU step size used in this study (5).
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Affiliation(s)
- Megan J Thorson
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA
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22
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Individual differences in behavioral estimates of cochlear nonlinearities. J Assoc Res Otolaryngol 2011; 13:91-108. [PMID: 21938546 DOI: 10.1007/s10162-011-0291-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Accepted: 08/29/2011] [Indexed: 02/07/2023] Open
Abstract
Psychophysical methods provide a mechanism to infer the characteristics of basilar membrane responses in humans that cannot be directly measured. Because these behavioral measures are indirect, the interpretation of results depends on several underlying assumptions. Ongoing uncertainty about the suitability of these assumptions and the most appropriate measurement and compression estimation procedures, and unanswered questions regarding the effects of cochlear hearing loss and age on basilar membrane nonlinearities, motivated this experiment. Here, estimates of cochlear nonlinearities using temporal masking curves (TMCs) were obtained in a large sample of adults of various ages whose hearing ranged from normal to moderate cochlear hearing loss (Experiment 1). A wide range of compression slopes was observed, even for subjects with similar ages and thresholds, which warranted further investigation (Experiment 2). Potential sources of variance contributing to these individual differences were explored, including procedural-related factors (test-retest reliability, suitability of the linear-reference TMC, probe sensation levels, and parameters of TMC fitting algorithms) and subject-related factors (age and age-related changes in temporal processing, strength of cochlear nonlinearities estimated with distortion-product otoacoustic emissions, estimates of changes in cochlear function from damage to outer hair cells versus inner hair cells). Subject age did not contribute significantly to TMC or compression slopes, and TMC slopes did not vary significantly with threshold. Test-retest reliability of TMCs suggested that TMC masker levels and the general shapes of TMCs did not change in a systematic way when re-measured many weeks later. Although the strength of compression decreased slightly with increasing hearing loss, the magnitude of individual differences in compression estimates makes it difficult to determine the effects of hearing loss and cochlear damage on basilar membrane nonlinearities in humans.
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Rodríguez J, Neely ST, Jesteadt W, Tan H, Gorga MP. Comparison of distortion-product otoacoustic emission growth rates and slopes of forward-masked psychometric functions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 129:864-875. [PMID: 21361444 PMCID: PMC3070994 DOI: 10.1121/1.3523340] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/02/2010] [Revised: 11/09/2010] [Accepted: 11/09/2010] [Indexed: 05/30/2023]
Abstract
Slopes of forward-masked psychometric functions (FM PFs) were compared with distortion-product otoacoustic emission (DPOAE) input/output (I/O) parameters at 1 and 6 kHz to test the hypothesis that these measures provide similar estimates of cochlear compression. Implicit in this hypothesis is the assumption that both DPOAE I/O and FM PF slopes are functionally related to basilar-membrane (BM) response growth. FM PF-slope decreased with signal level, but this effect was reduced or reversed with increasing hearing loss; there was a trend of decreasing psychometric function (PF) slope with increasing frequency, consistent with greater compression at higher frequencies. DPOAE I/O functions at 6 kHz exhibited an increase in the breakpoint of a two-segment slope as a function of hearing loss with a concomitant decrease in the level of the distortion product (L(d)). Results of the comparison between FM PF and DPOAE I/O parameters revealed only a weak correlation, suggesting that one or both of these measures may provide unreliable information about BM compression.
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Affiliation(s)
- Joyce Rodríguez
- Starkey Hearing Research Center, 2150 Shattuck Avenue, Suite 408, Berkeley, California 94704-1345, USA.
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24
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Almeida PPD, Sanches SGG, Carvallo RMM. Otoacoustic emissions growth rate threshold: distortion product in neonates. PRO-FONO : REVISTA DE ATUALIZACAO CIENTIFICA 2011; 22:409-14. [PMID: 21271091 DOI: 10.1590/s0104-56872010000400008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/11/2010] [Accepted: 11/30/2010] [Indexed: 11/22/2022]
Abstract
BACKGROUND Distortion product otoacoustic emission measures (DPOAE) verifies, among other characteristics, the emergence and growth rate of the DPOAE response according to sound stimulus intensity (growth curve). AIM To estimate the DPOAE threshold in neonates according to the DPOAE growth curve at 2 kHz and 4 kHz, with stimulus presentation ranging between 35 and 70 dB SPL. METHOD Participants were 51 neonates, with 24 to 84 hours of life and with no indication of risk for hearing impairment. The DPOAE were registered in the growth curve function at 2 kHz and at 4 kHz. Neonates were evaluated during the period of hospital stay, after birth. Three possible thresholds were considered (LIM 1, LIM 2 and LIM 3) based on the presence of response at 3 dB SPL in the signal to noise ratio. RESULTS The average thresholds intensities ranged from 47.55 to 49.85 dB at 2 kHz and from 55.52 to 59.94 dB at 4 kHz. The mean amplitude response ranged from 6.67 to 8.27 dB at 2 kHz and from 6.99 to 11.35 dB at 4 kHz. There was significant difference between the three thresholds for the two studied frequencies. CONCLUSION The procedure was feasible for the neonatal population revealing mean thresholds of up to 60 dB for both frequencies. Even though participants presented elevated thresholds, robust amplitude responses were observed.
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Müller J, Dietrich S, Janssen T. Impact of three hours of discotheque music on pure-tone thresholds and distortion product otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2010; 128:1853-1869. [PMID: 20968358 DOI: 10.1121/1.3479535] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The aim of this study was to investigate whether distortion product otoacoustic emissions (DPOAEs) are a suitable means for detecting changes in outer hair cell (OHC) functionality due to exposure to three hours of discotheque music and whether efferent reflex strength of the medial olivocochlear bundle is able to predict the ear's susceptibility to high-level noise. High-resolution DPOAEs (Δf(2)=47 Hz) were recorded between 3.5 and 4.5 kHz at close-to-threshold primary tone levels. For comparison, high-resolution pure-tone audiometry was conducted in the same frequency range. Efferent reflex strength was measured by means of DPOAEs at a specific frequency with and without contralateral acoustic stimulation. A significant deterioration of more than 10 dB was found for pure-tone thresholds and DPOAE levels indicating that three hours of high-level noise exert a considerable influence on hearing capability and OHC functionality. A significant correlation between shifts in pure-tone threshold and shifts in DPOAE level occurred when removing data with differing calibration across measurements. There was no clear correlation between efferent reflex strength and shifts in pure-tone threshold or shifts in DPOAE level suggesting that the applied measures of efferent reflex strength may not be suitable for quantifying individual vulnerability to noise.
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Affiliation(s)
- Jörg Müller
- Hals-Nasen-Ohrenklinik, Technische Universität München, Ismaningerstraße 22, 81675 Munich, Germany
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26
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He W, Fridberger A, Porsov E, Ren T. Fast reverse propagation of sound in the living cochlea. Biophys J 2010; 98:2497-505. [PMID: 20513393 DOI: 10.1016/j.bpj.2010.03.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2009] [Revised: 02/24/2010] [Accepted: 03/03/2010] [Indexed: 10/19/2022] Open
Abstract
The auditory sensory organ, the cochlea, not only detects but also generates sounds. Such sounds, otoacoustic emissions, are widely used for diagnosis of hearing disorders and to estimate cochlear nonlinearity. However, the fundamental question of how the otoacoustic emission exits the cochlea remains unanswered. In this study, emissions were provoked by two tones with a constant frequency ratio, and measured as vibrations at the basilar membrane and at the stapes, and as sound pressure in the ear canal. The propagation direction and delay of the emission were determined by measuring the phase difference between basilar membrane and stapes vibrations. These measurements show that cochlea-generated sound arrives at the stapes earlier than at the measured basilar membrane location. Data also show that basilar membrane vibration at the emission frequency is similar to that evoked by external tones. These results conflict with the backward-traveling-wave theory and suggest that at low and intermediate sound levels, the emission exits the cochlea predominantly through the cochlear fluids.
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Affiliation(s)
- Wenxuan He
- Oregon Hearing Research Center, Department of Otolaryngology and Head & Neck Surgery, Oregon Health & Science University, Portland, Oregon, USA
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27
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Clavier O, Norris J, Dietz A. A comparison of the nonlinear response of the ear to air and to bone-conducted sound. Hear Res 2010; 263:224-32. [DOI: 10.1016/j.heares.2010.03.004] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 03/08/2010] [Accepted: 03/10/2010] [Indexed: 10/19/2022]
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Neely ST, Johnson TA, Kopun J, Dierking DM, Gorga MP. Distortion-product otoacoustic emission input/output characteristics in normal-hearing and hearing-impaired human ears. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 126:728-38. [PMID: 19640039 PMCID: PMC2730716 DOI: 10.1121/1.3158859] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/27/2009] [Revised: 05/15/2009] [Accepted: 05/26/2009] [Indexed: 05/23/2023]
Abstract
Distortion-product otoacoustic emission (DPOAE) input/output (I/O) functions were measured in 322 ears of 176 subjects at as many as 8 f(2) frequencies per ear for a total of 1779 I/O functions. The f(2) frequencies ranged from 0.7 to 8 kHz in half-octave steps. Behavioral thresholds (BTs) at the f(2) frequencies ranged from -5 to 60 dB hearing loss (HL). Both linear-pressure and nonlinear, two-slope functions were fitted to the data. The two-slope function describes I/O compression as output-controlled self-suppression. Most I/O functions (96%) were better fitted by the two-slope method. DPOAE thresholds based on each method were used to predict BTs. Compared to estimates based on linear-pressure functions, individual BTs predicted from DPOAE thresholds based on the two-slope model had lower residual error and accounted for more variance. Another advantage of the two-slope method is that it provides an estimate of response growth rate (RGR) that is not tied to threshold. At all frequencies, the median low-level RGR (across I/O functions of the same f(2) and BT) usually increased as BT increased, while high-level compression decreased. The observed characteristics of DPOAE I/O functions are consistent with the loss of cochlear compression that is typically associated with mild-to-moderate HL.
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Affiliation(s)
- Stephen T Neely
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, NE 68131, USA
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Lopez-Poveda EA, Johannesen PT, Merchán MA. Estimation of the degree of inner and outer hair cell dysfunction from distortion product otoacoustic emission input/output functions. ACTA ACUST UNITED AC 2009. [DOI: 10.1080/16513860802622491] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Stenfelt S. Towards understanding the specifics of cochlear hearing loss: A modelling approach. Int J Audiol 2009; 47 Suppl 2:S10-5. [DOI: 10.1080/14992020802307396] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Epstein M, Silva I. Analysis of parameters for the estimation of loudness from tone-burst otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 125:3855-3864. [PMID: 19507968 DOI: 10.1121/1.3106531] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
There is evidence that tone-burst otoacoustic emissions (TBOAEs) might be useful for estimating loudness. However, within-listener comparisons between loudness and TBOAE measurements are an essential prerequisite to determine appropriate analysis parameters for loudness estimation from TBOAE measurements. The purpose of the present work was to collect TBOAE measurements and loudness estimates across a wide range of levels in the same listeners. Therefore, TBOAEs were recorded for 1- and 4-kHz stimuli and then analyzed using a wide range of parameters to determine which parameter set yielded the lowest mean-square-error estimation of loudness with respect to a psychoacoustical, cross-modality-matching procedure and the inflected exponential (INEX) loudness model. The present results show strong agreement between 1-kHz loudness estimates derived from TBOAEs and loudness estimated using cross-modality matching (CMM), with TBOAE estimation accounting for almost 90% of the CMM variance. Additionally, the results indicate that analysis parameters may vary within a reasonable range without compromising the results (i.e., the estimates exhibit some parametric robustness). The lack of adequate parametric optimization for TBOAEs at 4 kHz suggests that measurements at this frequency are strongly contaminated by ear-canal resonances, meaning that deriving loudness estimates from TBOAEs at this frequency is significantly more challenging than at 1 kHz.
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Affiliation(s)
- Michael Epstein
- Department of Speech-Language Pathology and Audiology, Auditory Modeling and Processing Laboratory, Communications and Digital Signal Processing Center, Northeastern University, Boston, Massachusetts 02115, USA.
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Otoacoustic detection of risk of early hearing loss in ears with normal audiograms: a 3-year follow-up study. Hear Res 2009; 251:10-6. [PMID: 19249340 DOI: 10.1016/j.heares.2009.02.008] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/12/2008] [Revised: 01/27/2009] [Accepted: 02/11/2009] [Indexed: 12/18/2022]
Abstract
INTRODUCTION Distortion product otoacoustic emissions (DPOAEs) are known to represent the contractile amplifier function of cochlear outer hair cells. It is known that low or absent DPOAEs are associated with hearing loss on audiograms. However, low DPOAEs can also be found associated with normal audiograms. It is unknown whether low DPOAEs in normal hearing ears are risk markers for subsequent early hearing loss when subjects are exposed to noise. MATERIALS AND METHODS A 3-year follow-up study was carried out on a population of pilots aged 20-40 years (n=521). Data collection consisted of tonal audiograms, DPOAEs measurements with a calculation of an index of abnormality (the IaDPOAE). Of the 521 pilots enrolled, 350 (67%) had follow-up data 3 years later. In pilots with normal audiograms (n=219, all frequencies=10dB HL), we observed the occurrence of hearing threshold shifts after 3 years depending on whether the IaDPOAE was initially high (group 1) or low (group 2). We used this index to test the hypothesis that reduced DPOAEs levels are potential ear vulnerability biomarkers in apparent normal hearing ears. After a 3-year follow-up, the initial IaDPOAE in normal hearing subjects was correlated with final noise-induced hearing threshold shifts at high frequencies (p<0.01). The occurrence of abnormal audiograms was significantly higher in group 1 compared to group 2 (p=0.003). In group 1, 13% of audiograms were found with at least one frequency 25dB HL compared to 3% of audiograms in group 2. In both groups, impairments occurred at high frequencies and hearing in the 4kHz frequency range was significantly more impaired in group 1 (p=0.035). Group 1 was associated with a relative risk of 2.29 (95% CI 1.26-4.16, p=0.005) of sustaining early hearing loss. There was no significant differences between groups for age and noise exposure. DISCUSSION In adults with a normal audiogram, ear vulnerability to noise could be elicited by the use of objective DPOAE measurements. A high IaDPOAE that corresponded to reduced DPOAE levels constitutes a risk for early hearing loss. This study emphasised the interest of DPOAE measurements in public health and occupational noise prevention policies. The IaDPOAE calculation may also be interesting for clinicians because no DPOAE index of abnormality is currently available.
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Johannesen PT, Lopez-Poveda EA. Cochlear nonlinearity in normal-hearing subjects as inferred psychophysically and from distortion-product otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:2149-2163. [PMID: 19062855 DOI: 10.1121/1.2968692] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The aim was to investigate the correlation between compression exponent, compression threshold, and cochlear gain for normal-hearing subjects as inferred from temporal masking curves (TMCs) and distortion-product otoacoustic emission (DPOAEs) input-output (I/O) curves. Care was given to reduce the influence of DPOAE fine structure on the DPOAE I/O curves. A high correlation between compression exponent estimates obtained with the two methods was found at 4 kHz but not at 0.5 and 1 kHz. One reason is that the DPOAE I/O curves show plateaus or notches that result in unexpectedly high compression estimates. Moderately high correlation was found between compression threshold estimates obtained with the two methods, although DPOAE-based values were around 7 dB lower than those based on TMCs. Both methods show that compression exponent and threshold are approximately constant across the frequency range from 0.5 to 4 kHz. Cochlear gain as estimated from TMCs was found to be approximately 16 dB greater at 4 than at 0.5 kHz. In conclusion, DPOAEs and TMCs may be used interchangeably to infer precise individual nonlinear cochlear characteristics at 4 kHz, but it remains unclear that the same applies to lower frequencies.
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Affiliation(s)
- Peter T Johannesen
- Unidad de Audicion Computacional y Psicoacustica, Instituto de Neurociencias de Castilla y Leon, Universidad de Salamanca, 37007 Salamanca, Spain
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Scheperle RA, Neely ST, Kopun JG, Gorga MP. Influence of in situ, sound-level calibration on distortion-product otoacoustic emission variability. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 124:288-300. [PMID: 18646977 PMCID: PMC2562746 DOI: 10.1121/1.2931953] [Citation(s) in RCA: 98] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Standing waves can cause errors during in-the-ear calibration of sound pressure level (SPL), affecting both stimulus magnitude and distortion-product otoacoustic emission (DPOAE) level. Sound intensity level (SIL) and forward pressure level (FPL) are two measurements theoretically unaffected by standing waves. SPL, SIL, and FPL in situ calibrations were compared by determining sensitivity of DPOAE level to probe-insertion depth (deep and "shallow") for a range of stimulus frequencies (1-8 kHz) and levels (20-60 dB). Probe-insertion depth was manipulated with the intent to shift the frequencies with standing-wave minima at the emission probe, introducing variability during SPL calibration. The absolute difference in DPOAE level between insertions was evaluated after correcting for an incidental change caused by the effect of ear-canal impedance on the emission traveling from the cochlea. A three-way analysis of variance found significant main effects for stimulus level, stimulus frequency, and calibration method, as well as significant interactions involving calibration method. All calibration methods exhibited changes in DPOAE level due to the insertion depth, especially above 4 kHz. However, SPL demonstrated the greatest changes across all stimulus levels for frequencies above 2 kHz, suggesting that SIL and FPL provide more consistent measurements of DPOAEs for frequencies susceptible to standing-wave calibration errors.
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Affiliation(s)
- Rachel A Scheperle
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
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Ménard M, Gallégo S, Berger-Vachon C, Collet L, Thai-Van H. Relationship between loudness growth function and auditory steady-state response in normal-hearing subjects. Hear Res 2008; 235:105-13. [DOI: 10.1016/j.heares.2007.10.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2007] [Revised: 10/10/2007] [Accepted: 10/20/2007] [Indexed: 10/22/2022]
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Rhode WS. Distortion product otoacoustic emissions and basilar membrane vibration in the 6-9 kHz region of sensitive chinchilla cochleae. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2007; 122:2725-2737. [PMID: 18189565 DOI: 10.1121/1.2785034] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) and basilar membrane (BM) vibration were measured simultaneously in the 6-9 kHz region of chinchilla cochleae. BM-Input-Output functions in a two-tone paradigm behaved similarly to DPOAEs for the 2f1-f2 component, nonmonotonic growth with the intensity of the lower frequency primary and a notch in the functions around 60 dB SPL. Ripples in frequency functions occur in both BM and OAE curves as a function of the distortion frequency. Optimum f2/f1 ratios for DPOAE generation are near 1.2. The slope of phase curves indicates that for low f2f1(<1.1) the emission source is the place location while for f2f1>1.1 the relative constancy of the phase function suggests that the place is the nonlinear region of f2, i.e., the wave location. Magnitudes of the DPOAEs increase rapidly above 60 dB SPL suggesting a different source or mechanism at high levels. This is supported by the observation that the high level DPOAE and BM-DP responses remain for a considerable period postmortem.
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Affiliation(s)
- William S Rhode
- Department of Physiology, University of Wisconsin, Madison, Wisconsin 53706, USA.
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Calandruccio L, Doherty KA, Carney LH, Kikkeri HN. Perception of temporally processed speech by listeners with hearing impairment. Ear Hear 2007; 28:512-23. [PMID: 17609613 PMCID: PMC2572868 DOI: 10.1097/aud.0b013e31806dc1fe] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The purpose of this study was to assess a new signal-processing strategy, Spatiotemporal Pattern Correction (SPC), for a group of listeners with varying degrees of sensorineural hearing loss. SPC is based on a physiological model of the level-dependent temporal response properties of auditory nerve (AN) fibers in normal and impaired ears. SPC attempts to "correct" AN response patterns by introducing time-varying group delays that differ across frequency channels. Listeners' speech intelligibility and preference judgments were obtained at different strengths of SPC processing. DESIGN Fifteen listeners, 12 with bilateral sensorineural hearing loss and 3 with normal hearing, participated in this study. Listeners with hearing impairment were separated into 3 groups (mild, moderate, and moderate-to-severe), based on their pure-tone averages at 0.5, 1, 2, and 4 kHz. All preference judgments were made using sentences from the Hearing-In-Noise-Test (HINT). The sentences were processed at five SPC strengths (1.0, 1.1, 1.2, 1.3, and 1.4). At an SPC strength of 1.0, the speech was processed through the SPC signal processor, becoming bandlimited, but no dynamic group delays were added to the signal. On each trial, listeners were presented a single sentence at two different SPC strengths, 1.0 (uncorrected) and a randomly selected SPC strength. Listeners were instructed to identify which of the two sentences they preferred. Sixteen vowel-consonant syllables, a subset of the Nonsense Syllable Test (NST), were used to assess speech intelligibility at three SPC strengths (1.0, 1.1, and 1.2). Listeners were asked to push one of 16 buttons on a response box that corresponded to the vowel-consonant syllable they heard. The moderate-to-severe hearing loss group was also tested using the low-probability sentences of the Speech-Perception-In-Noise (SPIN) test. RESULTS Listeners with normal hearing and listeners with mild hearing loss preferred the quality of uncorrected sentences (SPC strength of 1.0) compared with SPC-processed sentences. As the strength of SPC increased, listeners' preference for uncorrected sentences also increased. Listeners with moderate and moderate-to-severe hearing loss had difficulty differentiating between uncorrected and lower strength SPC-processed sentences but strongly preferred the uncorrected sentences as compared with high strength SPC-processed sentences. Vowel-consonant intelligibility was not improved or degraded by SPC. Sentence recognition scores for listeners with moderate-to-severe hearing loss decreased with SPC processing. CONCLUSIONS Although SPC-processed speech was not preferred by listeners with hearing loss, the listeners with a more moderate degree of impairment could not differentiate the unprocessed sentences from the SPC processed sentences. Speech intelligibility was not improved by SPC processing.
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Affiliation(s)
- Lauren Calandruccio
- Department of Communication Sciences and Disorders, Institute for Sensory Research, Syracuse University, Syracuse, NY 13244-5290, USA.
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Gorga MP, Neely ST, Dierking DM, Kopun J, Jolkowski K, Groenenboom K, Tan H, Stiegemann B. Low-frequency and high-frequency cochlear nonlinearity in humans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2007; 122:1671. [PMID: 17927427 PMCID: PMC2440918 DOI: 10.1121/1.2751265] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
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.
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Affiliation(s)
- Michael P Gorga
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
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Goldman B, Sheppard L, Kujawa SG, Seixas NS. Modeling distortion product otoacoustic emission input/output functions using segmented regression. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 120:2764-76. [PMID: 17139737 DOI: 10.1121/1.2258871] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) are low-level acoustic signals, the detection of which involves extraction from a background of noise. Boege and Janssen [J. Acoust. Soc. Am. 111, 1810-1818 (2002)] described a method for modeling the presence and growth of these responses. While improving growth function parameter estimation, this technique excludes a significant fraction of the data (especially low-level responses), and relies on ad hoc model fit acceptance criteria. The statistical difficulties associated with these limitations are described, and a weighted segmented linear regression model that avoids them is proposed. A simple test is presented for the presence of DPOAE growth. This technique is compared to that of Boege and Janssen in a dataset of 9 556 input/output (I/O) functions collected over 4 years on 866 ears from 379 construction apprentices and 63 age-matched controls. Comparisons are made on the entire dataset and within audiometric hearing loss categories. Segmented regression avoids the statistical pitfalls of the previous method, allows estimation of the threshold and slope of auditory response on a far greater number of I/O functions, and improves estimation of these parameters in this dataset. The potential for this method to yield more sensitive metrics of hearing function and compromise is discussed.
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Affiliation(s)
- Bryan Goldman
- Fred Hutchinson Cancer Research Center, Seattle, Washington 98109, USA
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Janssen T, Niedermeyer HP, Arnold W. Diagnostics of the Cochlear Amplifier by Means of Distortion Product Otoacoustic Emissions. ORL J Otorhinolaryngol Relat Spec 2006; 68:334-9. [PMID: 17065826 DOI: 10.1159/000095275] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Distortion product otoacoustic emission (DPOAE) growth functions reflect the active nonlinear cochlear sound processing when using a primary-tone setting which accounts for the different compressions of the two primaries at the DPOAE generation site and hence provide a measure for objectively assessing cochlear sensitivity and compression. DPOAE thresholds can be derived from extrapolated DPOAE input/output (I/O) functions independently of the noise floor and consequently can serve as a unique measure for reading DPOAE measurements. The thus-estimated DPOAE thresholds exhibit a close correspondence to behavior audiometric thresholds and thus can be used for reconstructing an audiogram, i.e., a DPOAE audiogram. The DPOAE I/O functions' slope increases with cochlear hearing loss and thus provides a measure for assessing recruitment. Hence, DPOAE I/O functions can give more information for diagnostic purposes than those of DP grams, transiently evoked OAEs (TEOAEs), or auditory brain stem responses (ABRs). DPOAE audiograms can be applied in pediatric audiology to assess cochlear dysfunction in a couple of minutes. In newborn hearing screening, they are able to detect transitory sound-conductive hearing loss and thus can help to reduce the rate of false-positive TEOAE responses in the early postnatal period. Since DPOAE I/O functions are correlated with loudness functions, DPOAEs offer the possibility of basic hearing aid adjustments, especially in infants and children. Extrapolated DPOAE I/O functions provide a tool for a fast automated frequency-specific and quantitative evaluation of hearing loss.
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Affiliation(s)
- Thomas Janssen
- Hals-Nasen-Ohrenklinik, Technische Universitat Munchen, Munchen, Deutschland.
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Withnell RH, Lodde J. In search of basal distortion product generators. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 120:2116-23. [PMID: 17069309 DOI: 10.1121/1.2338291] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
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, amplitude-modulated, or continuously varying in level, stimulus tones with f2/f1= 1.2 and f2 =8000-8940 Hz 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 = 80 dB sound pressure level (SPL).
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Affiliation(s)
- Robert H Withnell
- Department of Speech and Hearing Sciences, Indiana University, 200 South Jordan Avenue, Bloomington, Indiana 47405, USA.
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Shi LF, Carney LH, Doherty KA. Correction of the peripheral spatiotemporal response pattern: a potential new signal-processing strategy. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2006; 49:848-55. [PMID: 16908879 PMCID: PMC2586948 DOI: 10.1044/1092-4388(2006/060)] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The purpose of this paper is to introduce a new signal-processing strategy, spatiotemporal pattern correction (SPC), that is based on our knowledge of the level-dependent temporal response properties of auditory nerve fibers in normal and impaired ears. In normal-hearing listeners, tuning is sharp for low-level inputs and broadens as input level increases. When peripheral filters change their shape with input level, the phase properties of the filters and the latency of the filter's response also change. However, in listeners with hearing loss, tuning is broad for both low- and high-level inputs. Thus, there is little change in the phase properties of the filters for different input levels. The SPC strategy manipulates the temporal aspects of different frequency channels of sounds in an attempt to "correct" for this abnormal spatiotemporal response pattern of the impaired ear. Quality judgments and intelligibility measures of speech processed at various SPC strengths were obtained from a small group of normal-hearing listeners and listeners with hearing loss. In general, listeners with hearing loss preferred sentences with some degree of SPC processing, whereas normal-hearing listeners preferred unprocessed sentences. Benefit from SPC on the nonsense syllable test varied greatly across phonemes and listeners. A more comprehensive study of listeners with different degrees and configurations of hearing loss is needed to determine the amount of SPC benefit.
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Affiliation(s)
- Lu-Feng Shi
- Institute for Sensory Research, Department of Communication Sciences and Disorders, Syracuse University, Syracuse, NY 13244, USA
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Johnson TA, Neely ST, Garner CA, Gorga MP. Influence of primary-level and primary-frequency ratios on human distortion product otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 119:418-28. [PMID: 16454296 PMCID: PMC2440916 DOI: 10.1121/1.2133714] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
The combined influence of primary-level differences (L1-L2) and primary-frequency ratio (f2/f1) on distortion product otoacoustic emission (DPOAE) level was investigated in 20 normal-hearing subjects. DPOAEs were recorded with continuously varying stimulus levels [Neely et al. J. Acoust. Soc. Am. 117, 1248-1259 (2005)] for the following stimulus conditions: f2= 1, 2, 4, and 8 kHz and f2/f1=1.05 to 1.4; various L1-L2, including one individually optimized to produce the largest DPOAE. For broadly spaced primary frequencies at low L2 levels, the largest DPOAEs were recorded when L1 was much higher than L2, with L1 remaining relatively constant as L2 increased. As f2/fl decreased, the largest DPOAEs were observed when L1 was closer to L2 and increased as L2 increased. Optimal values for L1-L2 and f2 f1 were derived from these data. In general, average DPOAE levels for the new L1-L2 and f2/f1 were equivalent to or larger than those observed for other stimulus combinations, including the L1-L2 described by Kummer et al. [J. Acoust. Soc. Am. 103, 3431-3444 (1998)] and those defined by Neely et al. in which L1-L2 was evaluated, but f2/f1 was fixed at 1.2.
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Abstract
Extrapolated DPOAE growth functions can be applied in ENT diagnostics for a specific assessment of cochlear dysfunction. In screening newborn hearing, they are able to detect transitory sound conductive hearing loss and thus help to reduce the rate of false positive TEOAE responses in the early postnatal period. Since DPOAE growth functions are correlated with loudness functions, DPOAEs offer the potential for basic hearing aid adjustment, especially in children. Extrapolated DPOAE I/O-functions provide a tool for a fast, automated frequency-specific and quantitative evaluation of hearing loss. However, DPOAE diagnostics is limited to a hearing loss of 50 dB HL. Thus, a combined measurement of DPOAE and AMFR would be useful.
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Affiliation(s)
- T Janssen
- Hals-Nasen-Ohren-Klinik der Technischen Universität München.
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Janssen T, Gehr DD, Klein A, Müller J. Distortion product otoacoustic emissions for hearing threshold estimation and differentiation between middle-ear and cochlear disorders in neonates. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2005; 117:2969-79. [PMID: 15957767 DOI: 10.1121/1.1853101] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Our aim in the present study was to apply extrapolated DPOAE I/O-functions [J. Acoust. Soc. Am. 111, 1810-1818 (2002); 113, 3275-3284 (2003)] in neonates in order to investigate their ability to estimate hearing thresholds and to differentiate between middle-ear and cochlear disorders. DPOAEs were measured in neonates after birth (mean age = 3.2 days) and 4 weeks later (follow-up) at 11 test frequencies between f2 = 1.5 and 8 kHz and compared to that found in normal hearing subjects and cochlear hearing loss patients. On average, in a single ear hearing threshold estimation was possible at about 2/3 of the test frequencies. A sufficient test performance of the approach is therefore suggested. Thresholds were higher at the first measurement compared to that found at the follow-up measurement. Since thresholds varied with frequency, transitory middle ear dysfunction due to amniotic fluid instead of cochlear immaturity is suggested to be the cause for the change in thresholds. DPOAE behavior in the neonate ears differed from that found in the cochlear hearing loss ears. From a simple model it was concluded that the difference between the estimated DPOAE threshold and the DPOAE detection threshold is able to differentiate between sound conductive and cochlear hearing loss.
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Affiliation(s)
- Thomas Janssen
- Hals-Nasen-Ohrenklinik, Technische Universität München, Ismaningerstrasse 22, D-81675 Munich, Germany.
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Schairer KS, Keefe DH. Simultaneous recording of stimulus-frequency and distortion-product otoacoustic emission input-output functions in human ears. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2005; 117:818-832. [PMID: 15759702 DOI: 10.1121/1.1850341] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Stimulus frequency otoacoustic emission (SFOAE) input-output (I/O) functions were elicited in normal-hearing adults using unequal-frequency primaries in equal-level and fixed-suppressor level (Ls) conditions. Responses were repeatable and similar across a range of primary frequency ratios in the fixed-Ls condition. In comparison to equal-frequency primary conditions [Schairer, Fitzpatrick, and Keefe, J. Acoust. Soc. Am. 114, 944-966 (2003)], the unequal-frequency, fixed-Ls condition appears to be more useful for characterizing SFOAE response growth and relating it to basilar-membrane response growth, and for testing the ability to predict audiometric thresholds. Simultaneously recorded distortion-product OAE (DPOAE) I/O functions had higher thresholds than SFOAE I/O functions, and they identified the onset of the nonlinear-distortion mechanism in SFOAEs. DPOAE threshold often corresponded to nonmonotonicities in SFOAE I/O functions. This suggests that the level-dependent nonmonotonicities and associated phase shifts in SFOAE I/O functions were due to varying degrees of cancellation of two sources of SFOAE, such as coherent reflection and distortion mechanisms. Level-dependent noise was observed on-band (at the frequencies of the stimuli) but not off-band, or in the DPOAEs. The variability was observed in ears with normal hearing and ears with cochlear implants. In general, these results indicate the source of the variability is biological, possibly from within the middle ear.
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Affiliation(s)
- Kim S Schairer
- Center for Hearing Research, Boys Town National Research Hospital, Omaha, Nebraska 68131, USA.
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Beattie RC, Kenworthy O, Neal-Johnson CM. Distortion Product Otoacoustic Emissions: Input–Output Functions for Primary-Tone Pairs at 1000, 2000 and 4000 Hz in Normal-Hearing Females. ACTA ACUST UNITED AC 2004. [DOI: 10.1375/audi.26.2.116.58273] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Mauermann M, Kollmeier B. Distortion product otoacoustic emission (DPOAE) input/output functions and the influence of the second DPOAE source. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2004; 116:2199-212. [PMID: 15532652 DOI: 10.1121/1.1791719] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) at 2f1-f2 (f2/f1 = 1.2) have two components from different cochlear sources, i.e., a distortion component generated near f2 and a reflection component from the characteristic site of fDP. The interaction of the two sources may negatively affect the DPOAE input/output (I/O) functions that are used to predict either auditory thresholds or the compression characteristics of the basilar membrane. This study investigates the influence of the reflection component on DPOAE I/O functions in a frequency range for f2 from 1500 to 4500 Hz in steps of 18 Hz. A time windowing procedure is used to separate the components from the two DPOAE sources. With decreasing stimulus level, the relative contribution of the reflection component increases. I/O functions from the separated distortion component (DCOAE I/O functions) only show smooth changes in shape and slope with frequency, while "standard" DPOAE I/O functions show rapid changes between adjacent frequencies, indicating a strong influence from the interference with the second DPOAE source. A reduced variability for adjacent frequencies can be seen as well for prediction of hearing thresholds, when using DCOAE instead of DPOAE I/O functions.
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Affiliation(s)
- Manfred Mauermann
- Medizinische Physik, Universität Oldenburg, D-26111 Oldenburg, Germany.
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Sisto R, Moleti A. Modeling the growth rate of distortion product otoacoustic emissions by active nonlinear oscillators. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2004; 116:1632-1638. [PMID: 15478429 DOI: 10.1121/1.1775278] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
In this work, growth-rate curves of the 2 f1-f2 distortion product otoacoustic emission (DPOAE) are analyzed in a population of 30 noise exposed subjects, including both normal-hearing and hearing impaired subjects. A particular embedded limit-cycle oscillator equation is used to model the cochlear resonant response at the cochlear places of the primary and secondary tone frequencies (f2 and 2 f1-f2). The parameters of the oscillator equation can be directly interpreted in terms of effectiveness of the cochlear feedback mechanisms associated with the active filter amplification. A two-sources paradigm is included in the model, in agreement with experimental evidence and with the assumptions of more detailed full cochlear models based on the transmission line formalism. According to this paradigm, DPOAEs are nonlinearly generated at the cochlear place that is resonant at frequency f2, and coherently reflected at the 2 f1-f2 place. The analysis shows that the model, which had been previously used to describe the relaxation dynamics of transient evoked otoacoustic emissions (TEOAEs), also correctly predicts the observed growth rate of the DPOAE response as a function of the primary tones amplitude. A significant difference is observed between normal and impaired ears. The comparison between the growth rate curves at different frequencies provides information about the dependence of cochlear tuning on frequency.
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Affiliation(s)
- Renata Sisto
- Dipartimento Igiene del Lavoro, ISPESL, Via Fontana Candida, 1, 00040 Monte Porzio Catone (Roma), Italy.
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