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Bader K, Dalhoff E, Dierkes L, Braun LH, Gummer AW, Zelle D. Reliable Long-Term Serial Evaluation of Cochlear Function Using Pulsed Distortion-Product Otoacoustic Emissions: Analyzing Levels and Pressure Time Courses. Ear Hear 2024; 45:1326-1338. [PMID: 38809242 PMCID: PMC11325968 DOI: 10.1097/aud.0000000000001522] [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: 08/27/2023] [Accepted: 04/10/2024] [Indexed: 05/30/2024]
Abstract
OBJECTIVES To date, there is no international standard on how to use distortion-product otoacoustic emissions (DPOAEs) in serial measurements to accurately detect changes in the function of the cochlear amplifier due, for example, to ototoxic therapies, occupational noise, or the development of regenerative therapies. The use of clinically established standard DPOAE protocols for serial monitoring programs appears to be hampered by multiple factors, including probe placement and calibration effects, signal-processing complexities associated with multiple sites of emission generation as well as suboptimal selection of stimulus parameters. DESIGN Pulsed DPOAEs were measured seven times within 3 months for f2 = 1 to 14 kHz and L2 = 25 to 80 dB SPL in 20 ears of 10 healthy participants with normal hearing (mean age = 32.1 ± 9.7 years). L1 values were computed from individual optimal-path parameters derived from the corresponding individual DPOAE level map in the first test session. Three different DPOAE metrics for evaluating the functional state of the cochlear amplifier were investigated with respect to their test-retest reliability: (1) the interference-free, nonlinear-distortion component level ( LOD ), (2) the time course of the DPOAE-envelope levels, LDP ( t ), and (3) the squared, zero-lag correlation coefficient ( ) between the time courses of the DPOAE-envelope pressures, pDP ( t ), measured in two sessions. The latter two metrics include the two main DPOAE components and their state of interference. RESULTS Collated over all sessions and frequencies, the median absolute difference for LOD was 1.93 dB and for LDP ( t ) was 2.52 dB; the median of was 0.988. For the low ( f2 = 1 to 3 kHz), mid ( f2 = 4 to 9 kHz), and high ( f2 = 10 to 14 kHz) frequency ranges, the test-retest reliability of LOD increased with increasing signal to noise ratio (SNR). CONCLUSIONS On the basis of the knowledge gained from this study on the test-retest reliability of pulsed DPOAE signals and the current literature, we propose a DPOAE protocol for future serial monitoring applications that takes into account the following factors: (1) separation of DPOAE components, (2) use of individually optimal stimulus parameters, (3) SNR of at least 15 dB, (4) accurate pressure calibration, (5) consideration of frequency- and level-dependent test-retest reliabilities and corresponding reference ranges, and (6) stimulus levels L2 that are as low as possible with sufficient SNR to capture the nonlinear functional state of the cochlear amplifier operating at its highest gain.
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Affiliation(s)
- Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Lore Helene Braun
- Department of Radiooncology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Anthony W. Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
| | - Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Tübingen, Germany
- Earlab GmbH, Tübingen, Germany
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Stiepan S, Shera CA, Abdala C. Characterizing a Joint Reflection-Distortion OAE Profile in Humans With Endolymphatic Hydrops. Ear Hear 2023; 44:1437-1450. [PMID: 37450653 PMCID: PMC10593104 DOI: 10.1097/aud.0000000000001387] [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] [Indexed: 07/18/2023]
Abstract
OBJECTIVES Endolymphatic hydrops (EH), a hallmark of Meniere disease, is an inner-ear disorder where the membranes bounding the scala media are distended outward due to an abnormally increased volume of endolymph. In this study, we characterize the joint-otoacoustic emission (OAE) profile, a results profile including both distortion- and reflection-class emissions from the same ear, in individuals with EH and speculate on its potential utility in clinical assessment and monitoring. DESIGN Subjects were 16 adults with diagnosed EH and 18 adults with normal hearing (N) matched for age. Both the cubic distortion product (DP) OAE, a distortion-type emission, and the stimulus-frequency (SF) OAE, a reflection-type emission, were measured and analyzed as a joint OAE profile. OAE level, level growth (input/output functions), and phase-gradient delays were measured at frequencies corresponding to the apical half of the human cochlea and compared between groups. RESULTS Normal hearers and individuals with EH shared some common OAE patterns, such as the reflection emissions being generally higher in level than distortion emissions and showing more linear growth than the more strongly compressed distortion emissions. However, significant differences were noted between the EH and N groups as well. OAE source strength (a metric based on OAE amplitude re: stimulus level) was significantly reduced, as was OAE level, at low frequencies in the EH group. These reductions were more marked for distortion than reflection emissions. Furthermore, two significant changes in the configuration of OAE input/output functions were observed in ears with EH: a steepened growth slope for reflection emissions and an elevated compression knee for distortion emissions. SFOAE phase-gradient delays at 40 dB forward-pressure level were slightly shorter in the group with EH compared with the normal group. CONCLUSIONS The underlying pathology associated with EH impacts the generation of both emission types, reflection and distortion, as shown by significant group differences in OAE level, growth, and delay. However, hydrops impacts reflection and distortion emissions differently. Most notably, DPOAEs were more reduced by EH than were SFOAEs, suggesting that pathologies associated with the hydropic state do not act identically on the generation of nonlinear distortion at the hair bundle and intracochlear reflection emissions near the peak of the traveling wave. This differential effect underscores the value of applying a joint OAE approach to access both intracochlear generation processes concurrently.
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Affiliation(s)
- Samantha Stiepan
- 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
| | - Carolina Abdala
- Auditory Research Center, Caruso Department of Otolaryngology, University of Southern California, Los Angeles, CA 90033, 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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Çoban Büyükbayraktar Z, Doğan M, Doruk C, Özel VY. Evaluation of rapid maxillary expansion or alternating rapid maxillary expansion and constriction on Eustachian tube function with audiological tests: A randomized clinical trial. Int J Pediatr Otorhinolaryngol 2023; 164:111424. [PMID: 36577199 DOI: 10.1016/j.ijporl.2022.111424] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 11/08/2022] [Accepted: 12/17/2022] [Indexed: 12/24/2022]
Abstract
OBJECTIVES Maxillary expansion improves the hearing function. This trial aimed to examine the effects of Eustachian tube function (ETF) with audiological tests in orthodontic patients who underwent rapid maxillary expansion (RME) or alternate rapid maxillary expansion and constriction (Alt-RAMEC) treatment. METHODS Forty individuals (mean age = 13.35 years) included in the trial had a healthy eardrum, no history of orthodontic treatment, maxillary constriction, mandibular constriction and were not affected by acute or chronic otitis. Patients were randomly assigned to one of two groups (n = 20 each): the RME protocol or the Alt-RAMEC protocol. ETF was evaluated using Williams' test at three time points: before expansion (T0), after expansion (T1), and in the 3rd month of retention (T2). RESULTS In the RME group, Eustachian tube dysfunction (ETD) was observed in 18 of 40 ears before expansion (T0). The RME group showed significant improvement in tube function in the 3rd month of retention (T2) (p = 0.003). In the Alt-RAMEC group, ETD was observed in 22 of the 40 ears at baseline (T0). Significant improvements in tubal function were observed in the Alt-RAMEC group after expansion (T1) (p = 0.008) and in the 3rd month of retention (T2) (p < 0.001). In the RME group, 17 of 18 ears recovered, while in the Alt-RAMEC group, 21 of 22 ears recovered. CONCLUSION Eustachian tube function improved in the RME and Alt-RAMEC groups compared to the pre-expansion period. REGISTRATION This trial was not registered.
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Affiliation(s)
| | - Mansur Doğan
- Department of Otorhinolaringology, Sivas Cumhuriyet University Faculty of Medicine, Turkey.
| | - Cenk Doruk
- Department of Orthodontics, Sivas Cumhuriyet University, Faculty of Dentistry, Turkey.
| | - Volkan Yüksel Özel
- Inonu University, Faculty of Health Sciences, Department of Audiology, Turkey.
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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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Vetešník A, Vencovský V, Gummer AW. An additional source of distortion-product otoacoustic emissions from perturbation of nonlinear force by reflection from inhomogeneities. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:1660. [PMID: 36182298 DOI: 10.1121/10.0013992] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Accepted: 08/20/2022] [Indexed: 06/16/2023]
Abstract
The basilar membrane in the cochlea can be modeled as an array of fluid coupled segments driven by stapes vibration and by the undamping nonlinear force simulating cochlear amplification. If stimulated with two tones, the model generates additional tones due to nonlinear distortion. These distortion products (DPs) can be transmitted into the ear canal and produce distortion-product otoacoustic emissions (DPOAEs) known to be generated in the healthy ear of various vertebrates. This study presents a solution for DPs in a two-dimensional nonlinear cochlear model with cochlear roughness-small irregularities in the impedance along the basilar membrane, which may produce additional DPs due to coherent reflection. The solution allows for decomposition of various sources of DPs in the model. In addition to the already described nonlinear-distortion and coherent-reflection mechanisms of DP generation, this study identifies a long-latency DPOAE component due to perturbation of nonlinear force. DP wavelets that are coherently reflected due to impedance irregularities travel toward the stapes across the primary generation region of DPs and there evoke perturbation of the nonlinear undamping force. The ensuing DP wavelets have opposite phase to the wavelets arising from coherent reflection, which results in partial cancellation of the coherent-reflection DP wavelets.
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Affiliation(s)
- Aleš Vetešník
- Department of Nuclear Chemistry, Czech Technical University in Prague, Prague 115 19, Czech Republic
| | - Václav Vencovský
- Department of Radioelectronics, Czech Technical University in Prague, Prague 166 27, Czech Republic
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls University Tübingen, Tübingen 72076, Germany
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Bader K, Dierkes L, Braun LH, Gummer AW, Dalhoff E, Zelle D. Test-retest reliability of distortion-product thresholds compared to behavioral auditory thresholds. Hear Res 2021; 406:108232. [PMID: 33984603 DOI: 10.1016/j.heares.2021.108232] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Revised: 03/15/2021] [Accepted: 03/24/2021] [Indexed: 10/21/2022]
Abstract
When referred to baseline measures, serial monitoring of pure-tone behavioral thresholds and distortion-product otoacoustic emissions (DPOAEs) can be used to detect the progression of cochlear damage. Semi-logarithmic DPOAE input-output (I/O) functions enable the computation of estimated distortion-product thresholds (EDPTs) by means of linear regression, a metric that provides a quantitative estimate of hearing loss due to cochlear-amplifier degradation. DPOAE wave interference and a suboptimal choice of stimulus levels limit the accuracy of EDPTs. This work identifies the test-retest reliability of EDPTs derived from short-pulse DPOAE level maps (EDPTLM), a method that circumvents limitations associated with both wave interference and suboptimal choice of stimulus levels. The test-retest reliability was compared to that of EDPTs derived from semi-logarithmic I/O functions (EDPTI/O) and that of behavioral thresholds acquired with pure-tone audiometry (PTA) and modified Békésy tracking audiometry (TA) to provide a foundation for identifying and interpreting significant threshold shifts. The DPOAE-based auditory thresholds (EDPTLM and EDPTI/O) and behavioral thresholds (PTA and TA) were recorded seven times within three months at 14 frequencies with f2 = 1-14 kHz in 20 ears from ten subjects with normal hearing (4PTA0.5-4kHz < 20 dB HL). To obtain EDPTLM, short-pulse DPOAEs were recorded using 21 L1,L2 pairs. Reconstruction of DPOAE growth behavior as a function of L1 and L2 using nonlinear curve fitting enabled the derivation of EDPTLM for each frequency. Test-retest reliability was determined using three different approaches: 1) centered thresholds, 2) average threshold differences, and 3) average absolute threshold differences, between each possible test session (N = 21). Test-retest reliability based on centered thresholds and average threshold differences showed no statistically significant difference between EDPTLM, EDPTI/O, PTA, and TA for the pooled analysis incorporating all stimulus frequencies. Average absolute threshold differences presented small but significant differences in test-retest reliability with median values of 3.00 dB for PTA, 3.20 dB for TA, 3.34 dB for EDPTLM, and 3.51 dB for EDPTI/O. A considerable frequency dependence of test-retest reliability was found; namely, the highest test-retest reliability was for EDPTLM at f2 = 11 - 14 kHz. Otherwise, at lower frequencies, the highest test-retest reliability was for TA at f2 =1 - 2 kHz. Overall, the test-retest reliability of EDPTLM was better than that of EDPTI/O and was similar to that for behavioral thresholds. Hence, deriving EDPTLM from individual level maps is a promising and sensitive method for objectively monitoring the state of the cochlea. Furthermore, the detection of an equidirectional threshold change at a single frequency in both EDPTLM and TA might allow reducing the threshold shift as indication of a follow-up examination from the clinical standard of 10 dB down to 5 dB. This stricter indicator might be beneficial when monitoring cochlear damage, for example ototoxicity, in the presence of (remnant) cochlear amplification at baseline.
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Affiliation(s)
- Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lore Helene Braun
- Department of Radiooncology, Eberhard-Karls-University Tübingen, Hoppe-Seyler-Straße 3, 72076 Tübingen, Germany; Current address: Department of Radiooncology, Marienhospital Stuttgart, Böheimstraße 37, 70199 Stuttgart, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany; Current address: Redwave Medical GmbH, Hans-Knöll-Str. 6, 07745 Jena, Germany
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Zelle D, Bader K, Dierkes L, Gummer AW, Dalhoff E. Derivation of input-output functions from distortion-product otoacoustic emission level maps. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 147:3169. [PMID: 32486784 DOI: 10.1121/10.0001142] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2020] [Accepted: 04/07/2020] [Indexed: 06/11/2023]
Abstract
Distortion-product otoacoustic emissions (DPOAEs) emerge from the cochlea when elicited with two tones of frequencies f1 and f2. DPOAEs mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Input-output (I/O) functions of DPOAE pressure at the cubic difference frequency, fDP=2f1-f2, enable the computation of estimated distortion-product thresholds (EDPTs), offering a noninvasive approach to estimate auditory thresholds. However, wave interference between the DPOAE components and suboptimal stimulus-level pairs reduces the accuracy of EDPTs. Here, the amplitude P of the nonlinear-distortion component is extracted from short-pulse DPOAE time signals. DPOAE level maps representing the growth behavior of P in L1,L2 space are recorded for 21 stimulus-level pairs and 14 frequencies with f2=1 to 14 kHz (f2/f1=1.2) from 20 ears. Reproducing DPOAE growth behavior using a least-squares fit approach enables the derivation of ridge-based I/O functions from model level maps. Objective evaluation criteria assess the fit results and provide EDPTs, which correlate significantly with auditory thresholds (p < 0.001). In conclusion, I/O functions derived from model level maps provide EDPTs with high precision but without the need of predefined optimal stimulus-level pairs.
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Affiliation(s)
- Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Katharina Bader
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn- Straße 5, 72076 Tübingen, Germany
| | - Linda Dierkes
- Department of Otolaryngology, Head and Neck Surgery, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn- Straße 5, 72076 Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
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Vencovský V, Vetešník A, Dalhoff E, Gummer AW. Distributed sources as a cause of abrupt amplitude decrease in cubic distortion-product otoacoustic emissions at high stimulus intensities. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:EL92. [PMID: 31472590 DOI: 10.1121/1.5119942] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 07/12/2019] [Indexed: 06/10/2023]
Abstract
The amplitudes of distortion-product otoacoustic emissions (DPOAEs) may abruptly decrease even though the stimulus level is relatively high. These notches observed in the DPOAE input/output functions or distortion-product grams have been hypothesized to be due to destructive interference between wavelets generated by distributed sources of the nonlinear-distortion component of DPOAEs. In this paper, simulations with a smooth cochlear model and its analytical solution support the hypothesis that destructive interference between individual wavelets may lead to the amplitude notches and explain the cause for onset and offset amplitude overshoots in the DPOAE signal measured for intensity pairs in the notches.
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Affiliation(s)
- Václav Vencovský
- Department of Radioelectronics, Czech Technical University in Prague, Technická 2, 166 27 Prague, Czech
| | - Aleš Vetešník
- Department of Nuclear Chemistry, Czech Technical University in Prague, Břehová 7, 115 19 Prague, Czech
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, ,
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard Karls University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, ,
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Vencovský V, Zelle D, Dalhoff E, Gummer AW, Vetešník A. The influence of distributed source regions in the formation of the nonlinear distortion component of cubic distortion-product otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:2909. [PMID: 31153314 DOI: 10.1121/1.5100611] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2018] [Accepted: 04/16/2019] [Indexed: 06/09/2023]
Abstract
Distortion product otoacoustic emissions (DPOAEs) are evoked by two stimulus tones with frequency f1 and f2 of ratio f2/f1 in the range between approximately 1.05 and 1.4. This study theoretically and experimentally analyzes the cubic 2f1-f2 DPOAE for different stimulus levels of one of the tones while the other is constant. Simulations for f2/f1 of 1.2 and moderate stimulus levels (30-70 dB sound pressure level) indicate that cubic distortion products are generated along a relatively large length of the basilar membrane, the extent of which increases with stimulus level. However, apical from the place of maximum nonlinear force, the wavelets generated by these distributed sources mutually cancel. Therefore, although the spatial extent of the primary DPOAE sources broadens with increasing stimulus level (up to 1.5 oct), the basilar-membrane region contributing to the DPOAE signal is relatively narrow (0.6 oct) and level independent. The observed dependence of DPOAE amplitude on stimulus level can be well-approximated by a point source at the basilar-membrane place where the largest distortion product (maximum of the nonlinear force) is generated. Onset and offset of the DPOAE signal may contain amplitude overshoots (complexities), which are in most cases asymmetrical. Two-tone suppression was identified as the main cause of these onset and offset complexities. DPOAE measurements in two normal-hearing subjects support the level dependence of the steady-state DPOAE amplitude and the asymmetry in the onset and offset responses predicted by the theoretical analysis.
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Affiliation(s)
- Václav Vencovský
- Department of Radioelectronics, Czech Technical University in Prague, Technická 2, 166 27 Prague 6, Czech Republic
| | - Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany
| | - Aleš Vetešník
- Department of Nuclear Chemistry, Czech Technical University in Prague, Břehová 7, 115 19 Prague, Czech Republic
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Zelle D, Dalhoff E, Gummer AW. Objective audiometry with DPOAEs : New findings for generation mechanisms and clinical applications. HNO 2019; 65:122-129. [PMID: 28470484 PMCID: PMC5554278 DOI: 10.1007/s00106-016-0267-y] [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] [Indexed: 11/30/2022]
Abstract
Background Distortion product otoacoustic emissions (DPOAEs) and transient-evoked otoacoustic emissions (TEOAEs) are sound waves generated as byproducts of the cochlear amplifier. These are measurable in the auditory canal and represent an objective method for diagnosing functional disorders of the inner ear. Conventional DPOAE and TEOAE methods permit detection of hearing impairment, but with less than desirable accuracy. Objective By accounting for DPOAE generation mechanisms, the aim is to improve the accuracy of inner-ear diagnosis. Methods DPOAEs consist of two components, which emerge at different positions along the cochlea and which may cause artifacts due to mutual interference. Here, the two components are separated in the time domain using short stimulus pulses. Optimized stimulus levels facilitate the acquisition of DPOAEs with maximum amplitudes. DPOAE and Békésy audiograms were recorded from 41 subjects in a clinically relevant frequency range of 1.5–6 kHz. Results The short stimulus pulses allowed artifact-free measurement of DPOAEs. Semilogarithmic input–output functions yielded estimated distortion product thresholds, which were significantly correlated with the subjectively acquired Békésy thresholds. In addition, they allowed detection of hearing impairment from 20 dB HL, with 95% sensitivity and only a 5% false-positive rate. This accuracy was achieved with a measurement time of about 1–2 min per frequency. Conclusion Compared to conventional DPOAE and TEOAE methods, separation of DPOAE components using short-pulse DPOAEs in combination with optimized stimulus parameters considerably enhances the accuracy of DPOAEs for diagnosing impairment of the cochlear amplifier.
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Affiliation(s)
- D Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany
| | - E Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany
| | - A W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, University of Tübingen, Elfriede-Aulhorn-Str. 5, 72076, Tübingen, Germany.
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Zelle D, Dalhoff E, Gummer AW. Comparison of time-domain source-separation techniques for short-pulse distortion-product otoacoustic emissions. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 142:EL544. [PMID: 29289117 DOI: 10.1121/1.5016466] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Distortion-product otoacoustic emissions (DPOAEs) are presumed to consist mainly of two components, a nonlinear-distortion component and a coherent-reflection component. Wave interference between these two components reduces the accuracy of DPOAEs when used to evaluate cochlear function. Here, short tone pulses are utilized to record DPOAE signals in normal-hearing subjects. DPOAE components are extracted from recordings at discrete frequencies using two different techniques in the time domain. The extracted DPOAE components are compared to recordings obtained with conventional, continuous primary tones.
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Affiliation(s)
- Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany , ,
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany , ,
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Strasse 5, 72076 Tübingen, Germany , ,
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Zelle D, Lorenz L, Thiericke JP, Gummer AW, Dalhoff E. Input-output functions of the nonlinear-distortion component of distortion-product otoacoustic emissions in normal and hearing-impaired human ears. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2017; 141:3203. [PMID: 28599560 PMCID: PMC5426960 DOI: 10.1121/1.4982923] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Distortion-product otoacoustic emissions (DPOAEs) arise in the cochlea in response to two tones with frequencies f1 and f2 and mainly consist of two components, a nonlinear-distortion and a coherent-reflection component. Wave interference between these components limits the accuracy of DPOAEs when evaluating the function of the cochlea with conventional continuous stimulus tones. Here, DPOAE components are separated in the time domain from DPOAE signals elicited with short stimulus pulses. The extracted nonlinear-distortion components are used to derive estimated distortion-product thresholds (EDPTs) from semi-logarithmic input-output (I/O) functions for 20 normal-hearing and 21 hearing-impaired subjects. I/O functions were measured with frequency-specific stimulus levels at eight frequencies f2 = 1,…, 8 kHz (f2/f1 = 1.2). For comparison, DPOAEs were also elicited with continuous primary tones. Both acquisition paradigms yielded EDPTs, which significantly correlated with behavioral thresholds (p < 0.001) and enabled derivation of estimated hearing thresholds (EHTs) from EDPTs using a linear regression relationship. DPOAE-component separation in the time domain significantly reduced the standard deviation of EHTs compared to that derived from continuous DPOAEs (p < 0.01). In conclusion, using frequency-specific stimulus levels and DPOAE-component separation increases the reliability of DPOAE I/O functions for assessing cochlear function and estimating behavioral thresholds.
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Affiliation(s)
- Dennis Zelle
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Lisa Lorenz
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - John P Thiericke
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Anthony W Gummer
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
| | - Ernst Dalhoff
- Section of Physiological Acoustics and Communication, Department of Otolaryngology, Eberhard-Karls-University Tübingen, Elfriede-Aulhorn-Straße 5, 72076 Tübingen, Germany
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