Acceptable Noise Level, Phoneme Recognition in Noise, and Measures of Auditory Efferent Activity

2005 ◽  
Vol 16 (08) ◽  
pp. 530-545 ◽  
Author(s):  
Ashley W. Harkrider ◽  
Steven Brad Smith
Keyword(s):  
Individual Differences ◽  
Noise Level ◽  
Otoacoustic Emissions ◽  
Intersubject Variability ◽  
Acoustic Reflex ◽  
Phoneme Recognition ◽  
Efferent Activity ◽  
Acceptable Noise Level ◽  
Auditory Efferent ◽  
Medial Olivocochlear

Acceptable noise level (ANL) is unrelated to sentence recognition in noise but may be related to phoneme recognition in noise (PRN). Individual differences in efferent activity in medial olivocochlear bundle (MOCB) and acoustic reflex (AR) pathways may account for intersubject variability in ANL and PRN. Monotic and dichotic ANL, monotic PRN, contralateral suppression of transient evoked otoacoustic emissions, and ipsilateral and contralateral acoustic reflex thresholds were measured in 31 adults with normal hearing. Results indicate that monotic ANL and PRN are unrelated. Monotic and dichotic ANL are related, suggesting that nonperipheral factors mediate ANL. Intersubject variability in ANL cannot be accounted for by individual differences in MOCB or AR activation. Intersubject variability in PRN cannot be accounted for by individual differences in MOCB or contralateral AR activation. It may be influenced by the ipsilateral AR pathway. Efferent activity in the contralateral AR arc is correlated with efferent activity in the MOCB.

Differences in Responses from the Cochleae and Central Nervous Systems of Females with Low versus High Acceptable Noise Levels

2006 ◽  
Vol 17 (09) ◽  
pp. 667-676 ◽  
Author(s):  
Ashley W. Harkrider ◽  
Joanna W. Tampas
Keyword(s):  
Auditory System ◽  
Background Noise ◽  
Otoacoustic Emissions ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Intersubject Variability ◽  
Hearing Sensitivity ◽  
Central Regions ◽  
Central Nervous Systems ◽  
Medial Olivocochlear

Studies of acceptable noise level (ANL) consistently report large intersubject variability in acceptance of background noise while listening to speech. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, or efferent activity of the medial olivocochlear pathway. An exploratory study was conducted to determine if differences in aggregate responses from the peripheral and central auditory system can account for intersubject variability in ANL. Click-evoked otoacoustic emissions (CEOAEs), binaural auditory brainstem responses (ABRs), and middle latency responses (MLRs) were measured in females with normal hearing with low (n = 6) versus high (n = 7) ANLs. Results of this preliminary study indicate no differences between the groups for CEOAEs or waves I or III of the ABR. Differences between the two groups emerge for the amplitudes of wave V of the ABR and for the Na-Pa component of the MLR, suggesting that physiological variations arising from more central regions of the auditory system may mediate background noise acceptance.

scholarly journals Frequency tuning of medial-olivocochlear-efferent acoustic reflexes in humans as functions of probe frequency

2012 ◽  
Vol 107 (6) ◽  
pp. 1598-1611 ◽  
Author(s):  
Watjana Lilaonitkul ◽  
John J. Guinan
Keyword(s):  
Otoacoustic Emissions ◽  
Frequency Tuning ◽  
Stimulus Frequency ◽  
Phase Changes ◽  
Acoustic Reflex ◽  
Wide Range ◽  
Acoustic Reflexes ◽  
Specific Feedback ◽  
Stimulus Frequency Otoacoustic Emissions ◽  
Medial Olivocochlear

The medial-olivocochlear (MOC) acoustic reflex is thought to provide frequency-specific feedback that adjusts the gain of cochlear amplification, but little is known about how frequency specific the reflex actually is. We measured human MOC tuning through changes in stimulus frequency otoacoustic emissions (SFOAEs) from 40-dB-SPL tones at probe frequencies ( fps) near 0.5, 1.0, and 4.0 kHz. MOC activity was elicited by 60-dB-SPL ipsilateral, contralateral, or bilateral tones or half-octave noise bands, with elicitor frequency ( fe) varied in half-octave steps. Tone and noise elicitors produced similar results. At all probe frequencies, SFOAE changes were produced by a wide range of elicitor frequencies with elicitor frequencies near 0.7–2.0 kHz being particularly effective. MOC-induced changes in SFOAE magnitude and SFOAE phase were surprisingly different functions of fe: magnitude inhibition largest for fe close to fp, phase change largest for fe remote from fp. The metric ΔSFOAE, which combines both magnitude and phase changes, provided the best match to reported (cat) MOC neural inhibition. Ipsilateral and contralateral MOC reflexes often showed dramatic differences in plots of MOC effect vs. elicitor frequency, indicating that the contralateral reflex does not give an accurate picture of ipsilateral-reflex properties. These differences in MOC effects appear to imply that ipsilateral and contralateral reflexes have different actions in the cochlea. The implication of these results for MOC function, cochlear mechanics, and the production of SFOAEs are discussed.

scholarly journals Auditory attention reduced ear-canal noise in humans, but not through medial olivocochlear efferent inhibition: Implications for measuring otoacoustic emissions during behavioral task performance

2018 ◽  
Author(s):  
Nikolas A. Francis ◽  
Wei Zhao ◽  
John J. Guinan
Keyword(s):  
Noise Level ◽  
Otoacoustic Emissions ◽  
Time Course ◽  
Sound Level ◽  
Behavioral Task ◽  
Ear Canal ◽  
Behavioral Experiments ◽  
Masking Noise ◽  
The Subject ◽  
Medial Olivocochlear

AbstractOtoacoustic emissions (OAEs) are often measured to non-invasively determine activation of medial olivocochlear (MOC) efferents in humans. Usually these experiments assume that ear-canal noise remains constant. However, changes in ear-canal noise have been reported in some behavioral experiments. We studied the variability of ear-canal noise in eight subjects who performed a two-interval-forced-choice (2IFC) sound-level-discrimination task on monaural tone pips in masking noise. Ear-canal noise was recorded directly from the unstimulated ear opposite the task ear. Recordings were also done with similar sounds presented, but no task done. In task trials, ear-canal noise was reduced at the time the subject did the discrimination, relative to the noise level earlier in the trial. In two subjects, there was a decrease in ear-canal noise, primarily at 1-2 kHz, with a time course similar to that expected from inhibition by MOC activity elicited by the task-ear masker noise. These were the only subjects with spontaneous OAEs (SOAEs). We hypothesize that the SOAEs were inhibited by MOC activity elicited by the task-ear masker. Based on the standard rationale in OAE experiments that large bursts of noise are artifacts due to subject movement, noise bursts above a sound-level criterion were removed. As the criterion was lowered and more high-and moderate-level noise bursts were removed, the reduction in noise level from the beginning of the trial to the time of the 2IFC discrimination became less. This pattern is opposite that expected from MOC inhibition (which is greater on lower-level sounds), but can be explained by the hypothesis that subjects move less and create fewer bursts of noise when they concentrate on doing the task. In contrast, for the six subjects with no SOAEs, in no-task trials the noise level was little changed throughout the trial. Our results show that measurements of MOC effects on OAEs must measure and account for changes in ear-canal noise, especially in behavioral experiments. The results also provide a novel way of showing the time course of the buildup of attention in ear-canal noise during a 2IFC task.

The Role of the Medial Olivocochlear Reflex in Acceptable Noise Level in Adults

2021 ◽  
Author(s):  
Abdullah M. Jamos ◽  
Blair Hosier ◽  
Shelby Davis ◽  
Thomas C. Franklin
Keyword(s):  
Noise Level ◽  
Background Noise ◽  
Objective Measure ◽  
Broadband Noise ◽  
Noise Tolerance ◽  
Medial Olivocochlear Reflex ◽  
Hearing Aid Use ◽  
Acceptable Noise Level ◽  
Medial Olivocochlear ◽  
The Relationship

Abstract Background The acceptable noise level (ANL) is a measurement used to quantify how much noise a person is willing to accept while listening to speech. ANL has been used to predict success with hearing aid use. However, physiological correlates of the ANL are poorly understood. One potential physiological correlate is the medial olivocochlear reflex (MOCR), which decreases the output of the cochlea and is thereby expected to increase noise tolerance. Purpose This study investigates the relationship between contralateral activation of the MOCR and tolerance of background noise. Research Design This study recruited 22 young adult participants with normal hearing. ANL was measured using the Arizona Travelogue recording under headphones presented at the most comfortable level (MCL) with and without multitalker babble noise. The MOCR strength was evaluated in all participants by measuring the cochlear microphonic (CM) with and without 40 dB sound pressure level contralateral broadband noise (CBBN). Data Analysis The CM observed in response to a 500-Hz tone was measured with and without CBBN, and changes in response to fast Fourier transform amplitude at 500 Hz were used as an indicator of the MOCR effect. The ANL was calculated by subtracting the maximum acceptable background noise level from the MCL. Participants were divided into two groups based on their ANL: low-ANL (ANL < 7 dB) and moderate-ANL (ANL ≥ 7 dB). An independent samples t-test was used to compare CM enhancement between low-ANL and moderate-ANL groups. Additionally, Pearson's correlation was used to investigate the relationship between the ANL and the MOCR effect on the CM. Results The results indicated that presentation of CBBN increased the CM amplitude, consistent with eliciting the MOCR. Participants in the low-ANL group had significantly larger CM enhancement than moderate-ANL participants. The results further revealed a significant correlation between the ANL and the MOCR effect on the CM. Conclusion This study suggests that a stronger MOCR, as assessed using CM enhancement, is associated with greater noise tolerance. This research provides a possible objective measure to predict background tolerance in patients and adds to our understanding about the MOCR function in humans.

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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