A Time-Course-Based Estimation of the Human Medial Olivocochlear Reflex Function Using Clicks

The auditory efferent system, especially the medial olivocochlear reflex (MOCR), is implicated in both typical auditory processing and in auditory disorders in animal models. Despite the significant strides in both basic and translational research on the MOCR, its clinical applicability remains under-utilized in humans due to the lack of a recommended clinical method. Conventional tests employ broadband noise in one ear while monitoring change in otoacoustic emissions (OAEs) in the other ear to index efferent activity. These methods, (1) can only assay the contralateral MOCR pathway and (2) are unable to extract the kinetics of the reflexes. We have developed a method that re-purposes the same OAE-evoking click-train to also concurrently elicit bilateral MOCR activity. Data from click-train presentations at 80 dB peSPL at 62.5 Hz in 13 young normal-hearing adults demonstrate the feasibility of our method. Mean MOCR magnitude (1.7 dB) and activation time-constant (0.2 s) are consistent with prior MOCR reports. The data also suggest several advantages of this method including, (1) the ability to monitor MEMR, (2) obtain both magnitude and kinetics (time constants) of the MOCR, (3) visual and statistical confirmation of MOCR activation.

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The Medial Olivocochlear Reflex Is Unlikely to Play a Role in Listening Difficulties in Children

Trends in Hearing ◽

10.1177/2331216519870942 ◽

2019 ◽

Vol 23 ◽

pp. 233121651987094 ◽

Cited By ~ 1

Author(s):

Sriram Boothalingam ◽

Chris Allan ◽

Prudence Allen ◽

David W. Purcell

Keyword(s):

Auditory Processing ◽

Otoacoustic Emissions ◽

Signal To Noise Ratio ◽

Stimulus Frequency ◽

Auditory Processing Disorder ◽

High Signal ◽

Medial Olivocochlear Reflex ◽

Distortion Product ◽

Medial Olivocochlear ◽

Age Range

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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Does Hyperandrogenism Affect the Otoacoustic Emissions and Medial Olivocochlear Reflex in Female Adults?

Otology & Neurotology ◽

10.1097/mao.0b013e31828dae3e ◽

2013 ◽

Vol 34 (5) ◽

pp. 784-789 ◽

Cited By ~ 2

Author(s):

Erdem Eren ◽

Ece Harman ◽

Seçil Arslanoğlu ◽

Kazm Önal ◽

Hüseyin Katlmiş

Keyword(s):

Otoacoustic Emissions ◽

Medial Olivocochlear Reflex ◽

Medial Olivocochlear

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Medial Olivocochlear Reflex Effects on Amplitude Growth Functions of Long- and Short-Latency Components of Click-Evoked Otoacoustic Emissions in Humans

Journal of Neurophysiology ◽

10.1152/jn.00410.2020 ◽

2021 ◽

Author(s):

Shawn Goodman ◽

Sriram Boothalingam ◽

Jeffery T Lichtenhan

Keyword(s):

Otoacoustic Emissions ◽

Dynamic Range ◽

Short Latency ◽

Medial Olivocochlear Reflex ◽

Time Frequency ◽

Growth Functions ◽

Sound Levels ◽

Amplitude Attenuation ◽

Slope Change ◽

Medial Olivocochlear

Functional outcomes of medial olivocochlear reflex (MOCR) activation, such as improved hearing in background noise and protection from noise damage, involve moderate to high sound levels. Previous noninvasive measurements of MOCR in humans focused primarily on otoacoustic emissions (OAEs) evoked at low sound levels. Interpreting MOCR effects on OAEs at higher levels is complicated by the possibility of the middle-ear muscle reflex and by components of OAEs arising from different locations along the length of the cochlear spiral. We overcame these issues by presenting click stimuli at a very slow rate and by time-frequency windowing the resulting click-evoked (CE)OAEs into short-latency (SL) and long-latency (LL) components. We characterized the effects of MOCR on CEOAE components using multiple measures to more comprehensively assess these effects throughout much of the dynamic range of hearing. These measures included CEOAE amplitude attenuation, equivalent input attenuation, phase, and slope of growth functions. Results show that MOCR effects are smaller on SL components than LL components, consistent with SL components being generated slightly basal of the characteristic frequency region. Amplitude attenuation measures showed the largest effects at the lowest stimulus levels, but slope change and equivalent input attenuation measures did not decrease at higher stimulus levels. These latter measures are less commonly reported and may provide insight into the variability in listening performance and noise susceptibility seen across individuals.

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Effects of Type 2 Diabetes on Otoacoustic Emissions and the Medial Olivocochlear Reflex

Otolaryngology ◽

10.1177/0194599814527574 ◽

2014 ◽

Vol 150 (6) ◽

pp. 1033-1039 ◽

Cited By ~ 3

Author(s):

Erdem Eren ◽

Ece Harman ◽

Seçil Arslanoğlu ◽

Kazım Önal

Keyword(s):

Type 2 Diabetes ◽

Otoacoustic Emissions ◽

Medial Olivocochlear Reflex ◽

Medial Olivocochlear

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Influence of acute hyperglycemia on otoacoustic emissions and the medial olivocochlear reflex

The Journal of the Acoustical Society of America ◽

10.1121/1.3676609 ◽

2012 ◽

Vol 131 (2) ◽

pp. 1296-1306 ◽

Cited By ~ 9

Author(s):

Peter G. Jacobs ◽

Dawn Konrad-Martin ◽

Garnett P. Mcmillan ◽

Daniel McDermott ◽

Stephen A. Fausti ◽

...

Keyword(s):

Otoacoustic Emissions ◽

Acute Hyperglycemia ◽

Medial Olivocochlear Reflex ◽

Medial Olivocochlear

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Correlation and Reliability of Behavioral and Otoacoustic-Emission Estimates of Contralateral Medial Olivocochlear Reflex Strength in Humans

Frontiers in Neuroscience ◽

10.3389/fnins.2021.640127 ◽

2021 ◽

Vol 15 ◽

Author(s):

Miriam I. Marrufo-Pérez ◽

Peter T. Johannesen ◽

Enrique A. Lopez-Poveda

Keyword(s):

Otoacoustic Emission ◽

Acoustic Stimulation ◽

Broadband Noise ◽

Distortion Product Otoacoustic Emission ◽

Detection Thresholds ◽

Medial Olivocochlear Reflex ◽

Distortion Product ◽

Healthy Humans ◽

Medial Olivocochlear ◽

Tone Detection

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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