Challenges in exploring the role of medial olivocochlear efferents in auditory tasks via otoacoustic emissions

2014 ◽  
Vol 135 (4) ◽  
pp. 2385-2385
Author(s):  
Magdalena Wojtczak ◽  
Jordan A. Beim ◽  
Andrew J. Oxenham
Keyword(s):  
Otoacoustic Emissions ◽  
Medial Olivocochlear Efferents ◽  
Medial Olivocochlear ◽  
Auditory Tasks

The Role of the Medial Olivocochlear Reflex in Psychophysical Masking and Intensity Resolution in Humans: A Review

2021 ◽  
Author(s):  
Skyler G. Jennings
Keyword(s):  
Otoacoustic Emissions ◽  
Acoustic Stimulation ◽  
Forward Masking ◽  
Frequency Resolution ◽  
Vestibular Neurectomy ◽  
Contralateral Acoustic Stimulation ◽  
Cochlear Gain ◽  
Medial Olivocochlear ◽  
Intensity Resolution

This review addresses the putative role of the medial olivocochlear (MOC) reflex on psychophysical masking and intensity resolution in humans. A framework for interpreting psychophysical results in terms of the expected influenced of the MOC reflex is introduced. This framework is used to review the effects of a precursor or contralateral acoustic stimulation on 1) simultaneous masking of brief tones, 2) behavioral estimates of cochlear gain and frequency resolution in forward masking, 3) the build-up and decay of forward masking, and 4) measures of intensity resolution. Support, or lack thereof, for a role of the MOC reflex in psychophysical perception is discussed in terms of studies on estimates of MOC strength from otoacoustic emissions and the effects of resection of the olivocochlear bundle in patients with vestibular neurectomy. Novel, innovative approaches are needed to resolve the dissatisfying conclusion that current results are unable to definitively confirm or refute the role of the MOC reflex in masking and intensity resolution.

scholarly journals Reflex Control of the Human Inner Ear: A Half-Octave Offset in Medial Efferent Feedback That Is Consistent With an Efferent Role in the Control of Masking

2009 ◽  
Vol 101 (3) ◽  
pp. 1394-1406 ◽  
Author(s):  
Watjana Lilaonitkul ◽  
John J. Guinan
Keyword(s):  
Otoacoustic Emissions ◽  
High Sensitivity ◽  
Outer Hair Cells ◽  
Tuning Curves ◽  
Cochlear Amplification ◽  
Inhibitory Feedback ◽  
Probe Frequency ◽  
Medial Olivocochlear ◽  
Human Inner Ear

The high sensitivity and frequency selectivity of the mammalian cochlea is due to amplification produced by outer hair cells (OHCs) and controlled by medial olivocochlear (MOC) efferents. Data from animals led to the view that MOC fibers provide frequency-specific inhibitory feedback; however, these studies did not measure intact MOC reflexes. To test whether MOC inhibition is primarily at the frequency that elicits the MOC activity, acoustically elicited MOC effects were quantified in humans by the change in otoacoustic emissions produced by 60-dB SPL tone and half-octave-band noise elicitors at different frequencies relative to a 40-dB SPL, 1-kHz probe tone. On average, all elicitors produced MOC effects that were skewed (elicitor frequencies -1 octave below the probe produced larger effects than those -1 octave above). The largest MOC effects were from elicitors below the probe frequency for contra- and bilateral elicitors but were from elicitors centered at the probe frequency for ipsilateral elicitors. Typically, ipsilateral elicitors produced larger effects than contralateral elicitors and bilateral elicitors produced effects near the ipsi+contra sum. Elicitors at levels down to 30-dB SPL produced similar patterns. Tuning curves (TCs) interpolated from these data were V-shaped with Q10s ∼2. These are sharper than MOC-fiber TCs found near 1 kHz in cats and guinea pigs. Because cochlear amplification is skewed (more below the best frequency of a cochlear region), these data are consistent with an anti-masking role of MOC efferents that reduces masking by reducing the cochlear amplification seen at 1 kHz.

scholarly journals Frequency tuning of the contralateral medial olivocochlear reflex in humans

2012 ◽  
Vol 108 (1) ◽  
pp. 25-30 ◽  
Author(s):  
Wei Zhao ◽  
Sumitrajit Dhar
Keyword(s):  
Otoacoustic Emissions ◽  
Frequency Tuning ◽  
Acoustic Trauma ◽  
Fixed Frequency ◽  
Sound Perception ◽  
Spontaneous Otoacoustic Emissions ◽  
Functional Roles ◽  
Cochlear Gain ◽  
Medial Olivocochlear

Activation of the medial olivocochlear (MOC) efferents attenuates cochlear gain and reduces the amplitudes of mechanical, electrical, and neural cochlear outputs. The functional roles of the MOC efferents are not fully understood, especially in humans, despite postulations that they are involved in protection against acoustic trauma, facilitation of transient-sound perception, etc. Delineating the frequency tuning properties of the MOC efferents would provide critical evidence to support or refute these postulated functional roles. By utilizing spontaneous otoacoustic emissions (SOAEs), a cochlear measure sensitive to MOC modulation, we systematically demonstrate in humans that the contralateral MOC reflex is tuned to a fixed frequency band between 500 and 1,000 Hz independent of SOAE frequency. Our results question the role of the MOC reflex in protection against acoustic trauma or facilitation of transient-sound perception.

scholarly journals No Change in Medial Olivocochlear Efferent Activity during an Auditory or Visual Task: Dual Evidence from Otoacoustic Emissions and Event-Related Potentials

2020 ◽  
Vol 10 (11) ◽  
pp. 894
Author(s):  
W. Wiktor Jedrzejczak ◽  
Rafal Milner ◽  
Malgorzata Ganc ◽  
Edyta Pilka ◽  
Henryk Skarzynski
Keyword(s):  
Otoacoustic Emissions ◽  
Matching Pursuit ◽  
Event Related Potentials ◽  
Resonant Mode ◽  
Acoustic Stimulation ◽  
Hearing Function ◽  
Related Potentials ◽  
Medial Olivocochlear ◽  
Auditory Tasks ◽  
Cas A

The medial olivocochlear (MOC) system is thought to be responsible for modulation of peripheral hearing through descending (efferent) pathways. This study investigated the connection between peripheral hearing function and conscious attention during two different modality tasks, auditory and visual. Peripheral hearing function was evaluated by analyzing the amount of suppression of otoacoustic emissions (OAEs) by contralateral acoustic stimulation (CAS), a well-known effect of the MOC. Simultaneously, attention was evaluated by event-related potentials (ERPs). Although the ERPs showed clear differences in processing of auditory and visual tasks, there were no differences in the levels of OAE suppression. We also analyzed OAEs for the highest magnitude resonant mode signal detected by the matching pursuit method, but again did not find a significant effect of task, and no difference in noise level or number of rejected trials. However, for auditory tasks, the amplitude of the P3 cognitive wave negatively correlated with the level of OAE suppression. We conclude that there seems to be no change in MOC function when performing different modality tasks, although the cortex still remains able to modulate some aspects of MOC activity.

scholarly journals The role of efferents in human auditory development: efferent inhibition predicts frequency discrimination in noise for children

2020 ◽  
Vol 123 (6) ◽  
pp. 2437-2448 ◽  
Author(s):  
Srikanta K. Mishra
Keyword(s):  
Frequency Discrimination ◽  
Childhood Development ◽  
Older Children ◽  
Efferent System ◽  
Efferent Inhibition ◽  
Hearing In Noise ◽  
Medial Olivocochlear Efferents ◽  
Medial Olivocochlear ◽  
Listening In Noise

Despite several decades of research, the functional role of medial olivocochlear efferents in humans remains controversial and is thought to be insignificant. Here it is shown that medial efferent inhibition strongly predicts frequency discrimination in noise for younger children but not for older children and adults. Young children are relatively more dependent on the efferent system for listening-in-noise. This study highlights the role of the efferent system in hearing-in-noise during childhood development.

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

2013 ◽  
Vol 34 (5) ◽  
pp. 784-789 ◽  
Author(s):  
Erdem Eren ◽  
Ece Harman ◽  
Seçil Arslanoğlu ◽  
Kazm Önal ◽  
Hüseyin Katlmiş
Keyword(s):  
Otoacoustic Emissions ◽  
Medial Olivocochlear Reflex ◽  
Medial Olivocochlear

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

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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