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Bolat C, Yaldız ZÇB. Evaluation of the Effect of Age on the Contralateral Acoustic Reflex Suppression Test in Individuals With Normal Hearing. Am J Audiol 2024; 33:964-971. [PMID: 39133833 DOI: 10.1044/2024_aja-24-00025] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024] Open
Abstract
PURPOSE The aim of this study is to investigate the age-related changes of the Contralateral Acoustic Reflex Suppression (CARS) test in individuals with normal hearing and to provide age-related normal values. METHOD The study included 66 individuals aged 18-65 years. The participants were divided into three age groups, respectively, 18-30 years, 31-45 years, and 46-65 years. Acoustic reflex threshold and acoustic reflex amplitude measurements were performed at frequencies of 500, 1000, and 2000 Hz in the presence and absence of suppressive noise from the contralateral ear. RESULTS In the comparison of suppression amounts according to age groups, the highest suppression amount at all frequencies was observed in the 18-30 years age group. CONCLUSIONS It is known that changes in the function of the efferent hearing system occur due to aging. In the CARS test, a decrease in the amount of suppression produced by the efferent system has been observed due to aging.
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Affiliation(s)
- Cihat Bolat
- Department of Audiology and Speech Disorders PhD Programme, Institute of Health Sciences, Ankara University, Turkey
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2
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Ruba S, Panda MR. Short-Term and Long-Term Stability of Medial Olivocochlear Reflex in Adults with Typical Hearing. Indian J Otolaryngol Head Neck Surg 2023; 75:297-300. [PMID: 37206843 PMCID: PMC10188698 DOI: 10.1007/s12070-022-03448-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2022] [Accepted: 12/25/2022] [Indexed: 01/03/2023] Open
Abstract
This study aimed to assess the stability of Medial Olivocochlear Reflex (MOCR) function in typical hearing adults with the use of Contralateral Suppression (CS) of Distortion Product Otoacoustic Emissions (DPOAEs). This study included fifty-three (90 ears) participants between the ages of 18-30. Participants were divided into 3 groups (Group A-daily stability, Group B-short-term stability, and Group C- long-term stability). For each group, 4 measurements (30 × 4 = 120sessions) were taken. Group A measurements were taken daily, Group B measurements were taken weekly and Group C measurements were taken monthly. DPOAEs and Contralateral Suppression of DPOAEs were measured for each group. Analyses indicated that Medial Olivocochlear Reflex (MOCR) measured through contralateral suppression of DPOAE was unstable. This result indicates a DPOAE-based measure of the MOCR was not repeated across time. A great deal has been learned using CS of DPOAEs to study medial efferent activation, but several unresolved methodological issues that could impact the data to produce poor stability across time. Those methodological issues need to be explored and researched in the future.
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Affiliation(s)
- S. Ruba
- Department of Audiology and Speech Language Pathology, SRM Medical College Hospital and Research Centre, SRM Institute of Science and Technology, Kattankulathur Campus, Chennai, Tamilnadu 603203 India
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M B, Swathi C, Shameer S. Estimation of efferent inhibition and speech in noise perception on vocal musicians and music sleepers: A comparative study. J Otol 2023; 18:91-96. [PMID: 37153705 PMCID: PMC10159755 DOI: 10.1016/j.joto.2023.02.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 01/30/2023] [Accepted: 02/07/2023] [Indexed: 02/11/2023] Open
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Santos ACD, Labanca L, Assumpção LR, Mancini PC, Carvalho SADS, Resende LMD. Reliability of Contralateral Suppression in Evoked Distortion Product Otoacoustic Emissions. Int Arch Otorhinolaryngol 2022; 26:e250-e259. [PMID: 35602270 PMCID: PMC9122768 DOI: 10.1055/s-0041-1733928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 04/07/2021] [Indexed: 11/25/2022] Open
Abstract
Introduction Distortion product otoacoustic emissions (DPOAE) and their suppression may be considered useful in monitoring cochlear function and the efferent auditory pathway inhibitory effect. Nonetheless, the establishment of reliable parameters of response variations is of great importance. Objectives To verify the replicability of test and retest in the research of the inhibitory effect of the efferent pathway using contralateral suppressing stimulus during DPOAE recording for clinical applicability. Methods Cross-sectional study with 48 volunteers, aged 18 to 30 years, with normal audiometric thresholds. The procedures included were audiometric and immittance measures to overrule any conductive or sensorineural conditions and DPOAE recordings without and with contralateral suppression with a 60 dBHL white noise. Distortion product otoacoustic emissions amplitudes were analyzed and compared in both conditions with Wilcoxon test, and the Spearman correlation test was used to assess test-retest reliability. Results The comparative analysis showed differences between amplitudes in test and retest conditions only in 1,500 Hz for DPOAE measures with all other tested frequencies showing no differences, and no difference was observed in all recorded frequencies in the test and retest comparison for DPOAE suppression. The degree of correlation between test and retest of DPOAE amplitude was good at 6,000 Hz and strong (r > 0.880) at the other frequencies. For DPOAE with suppression, all frequencies presented strong correlation between test and retest: 1,500 Hz (r = 0.880), 2,000 Hz (r = 0.882), 3,000 Hz (r = 0.940), and 6,000 Hz (r = 0.957). Conclusions The study found good replicability in contralateral suppression of DPOAE with potential clinical applicability, and we recommend conducting the test from 2000Hz to higher frequencies for more reliable results.
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Affiliation(s)
- Ana Carolina dos Santos
- Department of Speech-Language Pathology and Audiology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Ludimila Labanca
- Department of Speech-Language Pathology and Audiology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Larissa Resende Assumpção
- Department of Speech-Language Pathology and Audiology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | - Patricia Cotta Mancini
- Department of Speech-Language Pathology and Audiology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
| | | | - Luciana Macedo de Resende
- Department of Speech-Language Pathology and Audiology, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brazil
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Marrufo-Pérez MI, Johannesen PT, Lopez-Poveda EA. Correlation and Reliability of Behavioral and Otoacoustic-Emission Estimates of Contralateral Medial Olivocochlear Reflex Strength in Humans. Front Neurosci 2021; 15:640127. [PMID: 33664649 PMCID: PMC7921326 DOI: 10.3389/fnins.2021.640127] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2020] [Accepted: 01/26/2021] [Indexed: 11/18/2022] Open
Abstract
The roles of the medial olivocochlear reflex (MOCR) in human hearing have been widely investigated but remain controversial. We reason that this may be because the effects of MOCR activation on cochlear mechanical responses can be assessed only indirectly in healthy humans, and the different methods used to assess those effects possibly yield different and/or unreliable estimates. One aim of this study was to investigate the correlation between three methods often employed to assess the strength of MOCR activation by contralateral acoustic stimulation (CAS). We measured tone detection thresholds (N = 28), click-evoked otoacoustic emission (CEOAE) input/output (I/O) curves (N = 18), and distortion-product otoacoustic emission (DPOAE) I/O curves (N = 18) for various test frequencies in the presence and the absence of CAS (broadband noise of 60 dB SPL). As expected, CAS worsened tone detection thresholds, suppressed CEOAEs and DPOAEs, and horizontally shifted CEOAE and DPOAE I/O curves to higher levels. However, the CAS effect on tone detection thresholds was not correlated with the horizontal shift of CEOAE or DPOAE I/O curves, and the CAS-induced CEOAE suppression was not correlated with DPOAE suppression. Only the horizontal shifts of CEOAE and DPOAE I/O functions were correlated with each other at 1.5, 2, and 3 kHz. A second aim was to investigate which of the methods is more reliable. The test–retest variability of the CAS effect was high overall but smallest for tone detection thresholds and CEOAEs, suggesting that their use should be prioritized over the use of DPOAEs. Many factors not related with the MOCR, including the limited parametric space studied, the low resolution of the I/O curves, and the reduced numbers of observations due to data exclusion likely contributed to the weak correlations and the large test–retest variability noted. These findings can help us understand the inconsistencies among past studies and improve our understanding of the functional significance of the MOCR.
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Affiliation(s)
- Miriam I Marrufo-Pérez
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Peter T Johannesen
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain
| | - Enrique A Lopez-Poveda
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain.,Instituto de Investigación Biomédica de Salamanca, Universidad de Salamanca, Salamanca, Spain.,Departamento de Cirugía, Facultad de Medicina, Universidad de Salamanca, Salamanca, Spain
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Boothalingam S, Allan C, Allen P, Purcell DW. The Medial Olivocochlear Reflex Is Unlikely to Play a Role in Listening Difficulties in Children. Trends Hear 2020; 23:2331216519870942. [PMID: 31558110 PMCID: PMC6767729 DOI: 10.1177/2331216519870942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The medial olivocochlear reflex (MOCR) has been implicated in several auditory processes. The putative role of the MOCR in improving speech perception in noise is particularly relevant for children who complain of listening difficulties (LiD). The hypothesis that the MOCR may be impaired in individuals with LiD or auditory processing disorder has led to several investigations but without consensus. In two related studies, we compared the MOCR functioning of children with LiD and typically developing (TD) children in the same age range (7-17 years). In Study 1, we investigated ipsilateral, contralateral, and bilateral MOCR using forward-masked click-evoked otoacoustic emissions (CEOAEs; n = 17 TD, 17 LiD). In Study 2, we employed three OAE types: CEOAEs (n = 16 TD, 21 LiD), stimulus frequency OAEs (n = 21 TD, 30 LiD), and distortion product OAEs (n = 17 TD, 22 LiD) in a contralateral noise paradigm. Results from both studies suggest that the MOCR functioning is not significantly different between the two groups. Some likely reasons for differences in findings among published studies could stem from the lack of strict data quality measures (e.g., high signal-to-noise ratio, control for the middle ear muscle reflex) that were enforced in the present study. The inherent variability of the MOCR, the subpar reliability of current MOCR methods, and the heterogeneity in auditory processing deficits that underlie auditory processing disorder make detecting clinically relevant differences in MOCR function impractical using current methods.
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Affiliation(s)
- Sriram Boothalingam
- Department of Communication Sciences and Disorders, University of Wisconsin, Madison, WI, USA.,Waisman Center, University of Wisconsin, Madison, WI, USA
| | - Chris Allan
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
| | - Prudence Allen
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
| | - David W Purcell
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
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Mertes IB. Establishing critical differences in ear-canal stimulus amplitude for detecting middle ear muscle reflex activation during olivocochlear efferent measurements. Int J Audiol 2019; 59:140-147. [DOI: 10.1080/14992027.2019.1673491] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
- Ian B. Mertes
- Department of Speech and Hearing Science, University of Illinois at Urbana-Champaign, Champaign, IL, USA
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Kalaiah MK, Lasrado A, Pinto N, Shastri U. Short Term Test-Retest Reliability of Contralateral Inhibition of Distortion Product Otoacoustic Emissions. J Audiol Otol 2018; 22:189-196. [PMID: 30126264 PMCID: PMC6233937 DOI: 10.7874/jao.2018.00038] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Accepted: 05/30/2018] [Indexed: 11/22/2022] Open
Abstract
BACKGROUND AND OBJECTIVES Strength of medial olivocochlear reflex can be measured reliably using contralateral inhibition of distortion product otoacoustic emissions (DPOAEs) when its fine structure is considered. However, measurement of fine structure of DPOAE is difficult with clinical equipment. Thus, this study investigated the clinically relevant test-retest reliability of contralateral inhibition of DPOAEs. Subjects and. METHODS Twenty-six young adults with normal hearing sensitivity participated. DPOAEs were recorded at 27 discrete f2 frequencies between 800 Hz and 8,000 Hz at frequency resolution of 8 points per octave with and without contralateral white noise presented at 50 dB SPL. To check for short term inter-session reliability, contralateral inhibition of DPOAEs were recorded in three sessions, two recording sessions on first day separated by 30 minutes and third time after one week of the first session. Within each session, DPOAEs were recorded twice in single probe-fit condition to test for intra-session reliability. RESULTS Cronbach's alpha was calculated having poor reliability (α≤ 0.7) of contralateral inhibition of DPOAEs in both intra-session and inter-session conditions for most of the tested frequencies. 95% confidence intervals of contralateral inhibition magnitude also showed large variability. CONCLUSIONS The current results showed that though DPOAE amplitudes were highly reliable across sessions, amount of inhibition of DPOAEs was not reliable when DPOAEs were measured at discrete frequencies. These findings are concurrent with the literature.
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Affiliation(s)
- Mohan Kumar Kalaiah
- Department of Audiology and Speech Language Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
| | - Alina Lasrado
- Department of Speech and Hearing Sciences, Arizona State University, Tempe, AZ, USA
| | - Nikita Pinto
- Early Learning Center (ELC), Bejai Kapikad, Mangalore, Karnataka, India
| | - Usha Shastri
- Department of Audiology and Speech Language Pathology, Kasturba Medical College, Mangalore, Manipal Academy of Higher Education, Manipal, Karnataka, India
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Hoth S, Baljić I. Current audiological diagnostics. GMS CURRENT TOPICS IN OTORHINOLARYNGOLOGY, HEAD AND NECK SURGERY 2017; 16:Doc09. [PMID: 29279727 PMCID: PMC5738938 DOI: 10.3205/cto000148] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Today's audiological functional diagnostics is based on a variety of hearing tests, whose large number takes account of the variety of malfunctions of a complex sensory organ system and the necessity to examine it in a differentiated manner and at any age of life. The objective is to identify nature and origin of the hearing loss and to quantify its extent as far as necessary to dispose of the information needed to initiate the adequate medical (conservative or operational) treatment or the provision with technical hearing aids or prostheses. Moreover, audiometry provides the basis for the assessment of impairment and handicap as well as for the calculation of the degree of disability. In the present overview, the current state of the method inventory available for practical use is described, starting from basic diagnostics over to complex special techniques. The presentation is systematically grouped in subjective procedures, based on psychoacoustic exploration, and objective methods, based on physical measurements: preliminary hearing tests, pure tone threshold, suprathreshold processing of sound intensity, directional hearing, speech understanding in quiet and in noise, dichotic hearing, tympanogram, acoustic reflex, otoacoustic emissions and auditory evoked potentials. Apart from a few still existing gaps, this method inventory covers the whole spectrum of all clinically relevant functional deficits of the auditory system.
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Affiliation(s)
- Sebastian Hoth
- Functional Area of Audiology, Department of Otolaryngology, University of Heidelberg, Germany
| | - Izet Baljić
- Department of Otolaryngology, HELIOS Hospital of Erfurt, Germany
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Kaipa R, Kumar UA. Functioning of medial olivocochlear bundle in right- and left-handed individuals. Laterality 2017; 22:445-454. [DOI: 10.1080/1357650x.2016.1217229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Meta-Analysis of Distortion Product Otoacoustic Emission Retest Variability for Serial Monitoring of Cochlear Function in Adults. Ear Hear 2016; 36:e251-60. [PMID: 25985018 DOI: 10.1097/aud.0000000000000176] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Distortion product otoacoustic emissions (DPOAEs) have long been heralded as a means to objectively monitor cochlear function and increasingly are becoming a key component in hearing surveillance programs for individuals at risk for ototoxic- and occupational noise-related hearing loss. Yet clinicians are unsure how to define clinically meaningful shifts in DPOAE level. In this study, a meta-analysis approach is used to synthesize the DPOAE level test-retest literature to construct a set of DPOAE level shift reference limits that can be used clinically to define a statistically significant emission change. DESIGN The authors reviewed all published articles identified through a Medline search using the terms "Otoacoustic Emission Variability," "Otoacoustic Emission Reliability," "Otoacoustic Emission Repeatability," and "Otoacoustic Emission Test Retest" restricted to DPOAEs, adults, and English language. Articles with DPOAE level data elicited by moderate stimulus levels for f2 frequencies of 1000, 2000, 4000, or 6000 Hz were selected because these stimulus parameters were relatively well represented in the literature. The authors only included articles that reported the standard error of the measurement (SEM) or from which the SEM could be calculated. Meta-analysis was used to estimate the population mean SEM over the included studies. Models were fit separately for each f2 primary and included days since baseline and study-specific random effects. RESULTS Ten DPOAE test-retest studies met inclusion criteria for this meta-analysis. The SEM values varied widely across published studies (0.57 to 3.9 dB) and were provided for relatively short time intervals (less than 15 days on average). Time, or days since baseline, was statistically significant at higher f2 frequencies (4000 and 6000 Hz). From the model results, 90% reference limits specific to the f2 and elapsed time between baseline and follow-up measurements were established. Reference limits provided correspond to negative (emission decrement) and positive (emission enhancement) shifts indicative of the amount of measurement variability that, using this approach, must be tolerated as "normal" fluctuations over time. Changes larger than the reference limits are considered significant and warrant follow-up testing. CONCLUSIONS The meta-analysis presented provides reference limits that are appropriate for a set of specific f2 frequencies and time intervals. The meta-analysis concerns the SEM statistic directly, so that any preferred reference limit can be computed from the results and should be predicated upon the screening application. The presumed advantage of this meta-analytic approach is increased precision relative to limits suggested by any of the individual studies included in the analysis.
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Within- and Across-Subject Variability of Repeated Measurements of Medial Olivocochlear-Induced Changes in Transient-Evoked Otoacoustic Emissions. Ear Hear 2016; 37:e72-84. [DOI: 10.1097/aud.0000000000000244] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Mishra SK, Abdala C. Stability of the medial olivocochlear reflex as measured by distortion product otoacoustic emissions. JOURNAL OF SPEECH, LANGUAGE, AND HEARING RESEARCH : JSLHR 2015; 58:122-134. [PMID: 25320951 PMCID: PMC4712848 DOI: 10.1044/2014_jslhr-h-14-0013] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2014] [Revised: 05/05/2014] [Accepted: 09/18/2014] [Indexed: 06/04/2023]
Abstract
PURPOSE The purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)-based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults. METHOD Data were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing adults to assess long-term stability. DPOAE level and phase measurements were recorded with and without contralateral acoustic stimulation. MOC reflex indices were computed by (a) noting contralateral acoustic stimulation-induced changes in DPOAE level (both absolute and normalized) at fine-structure peaks, (b) recording the effect as a vector difference, and (c) separating DPOAE components and considering a component-specific metric. RESULTS Analyses indicated good repeatability of all indices of the MOC reflex in most frequency ranges. Short- and long-term repeatability were generally comparable. Indices normalized to a subject's own baseline fared best, showing strong short- and long-term stability across all frequency intervals. CONCLUSIONS These results suggest that fine-resolution DPOAE-based measures of the MOC reflex measured at strategic frequencies are stable, and natural variance from day-to-day or week-to-week durations is small enough to detect between-group differences and possibly to monitor intervention-related success. However, this is an empirical question that must be directly tested to confirm its utility.
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Marshall L, Lapsley Miller JA, Guinan JJ, Shera CA, Reed CM, Perez ZD, Delhorne LA, Boege P. Otoacoustic-emission-based medial-olivocochlear reflex assays for humans. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 136:2697-713. [PMID: 25373970 PMCID: PMC5392105 DOI: 10.1121/1.4896745] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/28/2013] [Revised: 09/15/2014] [Accepted: 09/18/2014] [Indexed: 05/20/2023]
Abstract
Otoacoustic emission (OAE) tests of the medial-olivocochlear reflex (MOCR) in humans were assessed for viability as clinical assays. Two reflection-source OAEs [TEOAEs: transient-evoked otoacoustic emissions evoked by a 47 dB sound pressure level (SPL) chirp; and discrete-tone SFOAEs: stimulus-frequency otoacoustic emissions evoked by 40 dB SPL tones, and assessed with a 60 dB SPL suppressor] were compared in 27 normal-hearing adults. The MOCR elicitor was a 60 dB SPL contralateral broadband noise. An estimate of MOCR strength, MOCR%, was defined as the vector difference between OAEs measured with and without the elicitor, normalized by OAE magnitude (without elicitor). An MOCR was reliably detected in most ears. Within subjects, MOCR strength was correlated across frequency bands and across OAE type. The ratio of across-subject variability to within-subject variability ranged from 2 to 15, with wideband TEOAEs and averaged SFOAEs giving the highest ratios. MOCR strength in individual ears was reliably classified into low, normal, and high groups. SFOAEs using 1.5 to 2 kHz tones and TEOAEs in the 0.5 to 2.5 kHz band gave the best statistical results. TEOAEs had more clinical advantages. Both assays could be made faster for clinical applications, such as screening for individual susceptibility to acoustic trauma in a hearing-conservation program.
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Affiliation(s)
- Lynne Marshall
- Naval Submarine Medical Research Laboratory, Box 900, Subase NLON, Box 900, Groton, Connecticut 06349-5900
| | - Judi A Lapsley Miller
- Naval Submarine Medical Research Laboratory, Box 900, Subase NLON, Box 900, Groton, Connecticut 06349-5900
| | - John J Guinan
- Eaton-Peabody Laboratory of Auditory Physiology, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, Massachusetts 02114
| | - Christopher A Shera
- Eaton-Peabody Laboratory of Auditory Physiology, Massachusetts Eye and Ear Infirmary, 243 Charles Street, Boston, Massachusetts 02114
| | - Charlotte M Reed
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Zachary D Perez
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Lorraine A Delhorne
- Research Laboratory of Electronics, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, Massachusetts 02139-4307
| | - Paul Boege
- Consultant, Hirschanger 17, D-82319, Starnberg, Germany
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Abstract
OBJECTIVE Cochlear reflectance (CR) is the cochlear contribution to ear-canal reflectance. CR is equivalent to an otoacoustic emission (OAE) deconvolved by forward pressure in the ear canal. Similar to other OAE measures, CR level is related to cochlear status. When measured using wideband noise stimuli, potential advantages of CR over other types of OAEs include (1) the capability to cover a wider frequency range more efficiently by requiring fewer measurements, (2) minimal influence on the recorded emission from the measurement system and middle ear, (3) lack of entrainment of spontaneous OAEs, and (4) easier interpretation because of the existence of an equivalent linear model, which validates the application of linear systems theory. The purposes of this study were to evaluate the reliability, assess the accuracy in a clinical screening paradigm, and determine the relation of CR to audiometric thresholds. Thus, this study represents an initial assessment of the clinical utility of CR. DESIGN Data were collected from 32 normal-hearing and 58 hearing-impaired participants. A wideband noise stimulus presented at seven stimulus levels (10 to 70 dB SPL, 10 dB steps) was used to elicit the CR. Reliability of CR was assessed using Cronbach's α, standard error of measurement, and absolute differences between CR data from three separate test sessions. Test performance was evaluated using clinical decision theory. The ability of CR to predict audiometric thresholds was evaluated using regression analysis. RESULTS CR repeatability across test sessions was similar to that of other clinical measurements. However, both the accuracy with which CR distinguished normal-hearing from hearing-impaired ears and the accuracy with which CR predicted audiometric thresholds were less than those reported in previous studies using distortion-product OAE measurements. CONCLUSIONS CR measurements are repeatable between test sessions, can be used to predict auditory status, and are related to audiometric thresholds. However, under current conditions, CR does not perform as well as other OAE measurements. Further developments in CR measurement and analysis methods may improve performance. CR has theoretical advantages for cochlear modeling, which may lead to improved interpretation of cochlear status.
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