Effect of contralateral acoustic stimulation on active cochlear micromechanical properties in human subjects: dependence on stimulus variables

1991 ◽  
Vol 65 (3) ◽  
pp. 724-735 ◽  
Author(s):  
E. Veuillet ◽  
L. Collet ◽  
R. Duclaux
Keyword(s):  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Suppressive Effect ◽  
Stimulus Level ◽  
Broadband Noise ◽  
Efferent System ◽  
Micromechanical Properties ◽  
Frequency Specificity ◽  
Efferent Neurons ◽  
Contralateral Stimulus

1. Outer hair cells (OHCs) have active micromechanical properties that are thought to be the origin of evoked otoacoustic emissions (EOAEs). In the present study, click-evoked otoacoustic emissions were recorded in humans with or without various contralateral acoustic stimulations. A previous study, concentrating on contralateral stimulation with broadband noise, had shown a decrease of the EOAE amplitude in humans. Results support a role for the efferent system in cochlear mechanics; indeed, medial efferent neurons of the olivocochlear bundle terminate on the OHCs. To obtain a better understanding of the medial efferent system functioning in humans, the present study looked at the contralateral suppressive effect as a function of stimulus parameters. 2. The study of the input-output function of the EOAE amplitude with and without a 50-dB SPL contralateral broadband noise showed that the suppressive effect was equivalent to a mean reduction of 3.77 dB. 3. For the EOAEs to tone pips, the contralateral suppressive effect was strongest when the contralateral ear stimuli were narrow bands that were centered around the central EOAE frequency. This frequency specificity disappeared for contralateral narrow band noise levels greater than 50 dB SPL. 4. The contralateral suppressive effect was also observed with transient contralateral sounds (nonfiltered clicks). Significant reductions of the EOAE amplitude were seen with contralateral click levels as low as 17.5 dB SL. Above this level, the EOAE amplitude decreased as the contralateral stimulus level increased. This effect was still present in subjects without any stapedial reflex, but absent in total unilateral hearing-loss subjects. Therefore this suppressive effect is unlikely to be due to alteration of the middle ear function or to transcranially conducted sound. 5. When the contralateral interclick interval exceeded 14.2 ms. the suppressive effect was smaller. With contralateral stimulus level maintained subjectively constant, the effect was found to disappear when the interclick interval was greater than 49.9 ms. A saturation of the contralateral suppressive effect was observed for click rates greater than 70/s (interclick interval less than 14.2 ms). 6. Our study confirms and specifies the contralateral sound suppression effect on cochlear mechanisms in humans, assessing the equivalent reduction, showing a frequency specificity and extending these findings to contralateral transient sounds. Any influence of the acoustic crosstalk was eliminated. A role played by middle ear muscles cannot be absolutely ruled out but is not necessary to produce such a contralateral suppressive effect (the effect being found in subjects after surgical removal of the stapedius muscle) and could not explain the frequency specificity.(ABSTRACT TRUNCATED AT 400 WORDS)

scholarly journals Identifying Otosclerosis with Aural Acoustical Tests of Absorbance, Group Delay, Acoustic Reflex Threshold, and Otoacoustic Emissions

2017 ◽  
Vol 28 (09) ◽  
pp. 838-860 ◽  
Author(s):  
Douglas H. Keefe ◽  
Kelly L. Archer ◽  
Kendra K. Schmid ◽  
Denis F. Fitzpatrick ◽  
M. Patrick Feeney ◽  
...  
Keyword(s):  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Group Delay ◽  
Surgical Intervention ◽  
Broadband Noise ◽  
Positive Pressure ◽  
Control Group ◽  
Corrective Surgery ◽  
Ear Canal ◽  
Reflex Threshold

AbstractOtosclerosis is a progressive middle-ear disease that affects conductive transmission through the middle ear. Ear-canal acoustic tests may be useful in the diagnosis of conductive disorders. This study addressed the degree to which results from a battery of ear-canal tests, which include wideband reflectance, acoustic stapedius muscle reflex threshold (ASRT), and transient evoked otoacoustic emissions (TEOAEs), were effective in quantifying a risk of otosclerosis and in evaluating middle-ear function in ears after surgical intervention for otosclerosis.To evaluate the ability of the test battery to classify ears as normal or otosclerotic, measure the accuracy of reflectance in classifying ears as normal or otosclerotic, and evaluate the similarity of responses in normal ears compared with ears after surgical intervention for otosclerosis.A quasi-experimental cross-sectional study incorporating case control was used. Three groups were studied: one diagnosed with otosclerosis before corrective surgery, a group that received corrective surgery for otosclerosis, and a control group.The test groups included 23 ears (13 right and 10 left) with normal hearing from 16 participants (4 male and 12 female), 12 ears (7 right and 5 left) diagnosed with otosclerosis from 9 participants (3 male and 6 female), and 13 ears (4 right and 9 left) after surgical intervention from 10 participants (2 male and 8 female).Participants received audiometric evaluations and clinical immittance testing. Experimental tests performed included ASRT tests with wideband reference signal (0.25–8 kHz), reflectance tests (0.25–8 kHz), which were parameterized by absorbance and group delay at ambient pressure and at swept tympanometric pressures, and TEOAE tests using chirp stimuli (1–8 kHz). ASRTs were measured in ipsilateral and contralateral conditions using tonal and broadband noise activators. Experimental ASRT tests were based on the difference in wideband-absorbed sound power before and after presenting the activator. Diagnostic accuracy to classify ears as otosclerotic or normal was quantified by the area under the receiver operating characteristic curve (AUC) for univariate and multivariate reflectance tests. The multivariate predictor used a small number of input reflectance variables, each having a large AUC, in a principal components analysis to create independent variables and followed by a logistic regression procedure to classify the test ears.Relative to the results in normal ears, diagnosed otosclerosis ears more frequently showed absent TEOAEs and ASRTs, reduced ambient absorbance at 4 kHz, and a different pattern of tympanometric absorbance and group delay (absorbance increased at 2.8 kHz at the positive-pressure tail and decreased at 0.7–1 kHz at the peak pressure, whereas group delay decreased at positive and negative-pressure tails from 0.35–0.7 kHz, and at 2.8–4 kHz at positive-pressure tail). Using a multivariate predictor with three reflectance variables, tympanometric reflectance (AUC = 0.95) was more accurate than ambient reflectance (AUC = 0.88) in classifying ears as normal or otosclerotic.Reflectance provides a middle-ear test that is sensitive to classifying ears as otosclerotic or normal, which may be useful in clinical applications.

scholarly journals Characterizing the Access of Cholinergic Antagonists to Efferent Synapses in the Inner Ear

2021 ◽  
Vol 15 ◽  
Author(s):  
Choongheon Lee ◽  
Anjali K. Sinha ◽  
Kenneth Henry ◽  
Anqi W. Walbaum ◽  
Peter A. Crooks ◽  
...  
Keyword(s):  
Inner Ear ◽  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Cholinergic Antagonists ◽  
Cholinergic Drugs ◽  
Administration Routes ◽  
Distortion Product ◽  
Vestibular Afferents ◽  
Auditory Physiology ◽  
Efferent Neurons

Stimulation of cholinergic efferent neurons innervating the inner ear has profound, well-characterized effects on vestibular and auditory physiology, after activating distinct ACh receptors (AChRs) on afferents and hair cells in peripheral endorgans. Efferent-mediated fast and slow excitation of vestibular afferents are mediated by α4β2*-containing nicotinic AChRs (nAChRs) and muscarinic AChRs (mAChRs), respectively. On the auditory side, efferent-mediated suppression of distortion product otoacoustic emissions (DPOAEs) is mediated by α9α10nAChRs. Previous characterization of these synaptic mechanisms utilized cholinergic drugs, that when systemically administered, also reach the CNS, which may limit their utility in probing efferent function without also considering central effects. Use of peripherally-acting cholinergic drugs with local application strategies may be useful, but this approach has remained relatively unexplored. Using multiple administration routes, we performed a combination of vestibular afferent and DPOAE recordings during efferent stimulation in mouse and turtle to determine whether charged mAChR or α9α10nAChR antagonists, with little CNS entry, can still engage efferent synaptic targets in the inner ear. The charged mAChR antagonists glycopyrrolate and methscopolamine blocked efferent-mediated slow excitation of mouse vestibular afferents following intraperitoneal, middle ear, or direct perilymphatic administration. Both mAChR antagonists were effective when delivered to the middle ear, contralateral to the side of afferent recordings, suggesting they gain vascular access after first entering the perilymphatic compartment. In contrast, charged α9α10nAChR antagonists blocked efferent-mediated suppression of DPOAEs only upon direct perilymphatic application, but failed to reach efferent synapses when systemically administered. These data show that efferent mechanisms are viable targets for further characterizing drug access in the inner ear.

Effect of topically applied povidone-iodine on transient evoked otoacoustic emissions in guinea pigs

2003 ◽  
Vol 117 (9) ◽  
pp. 700-703 ◽  
Author(s):  
Recep Yagiz ◽  
Abdullah Tas ◽  
Cem Uzun ◽  
Mustafa Kemal Adali ◽  
Muhsin Koten ◽  
...  
Keyword(s):  
Middle Ear ◽  
Guinea Pigs ◽  
Otoacoustic Emissions ◽  
Povidone Iodine ◽  
Positive Control ◽  
Middle Ear Surgery ◽  
Iodine Solution ◽  
Before And After ◽  
Transiently Evoked Otoacoustic Emissions ◽  
Povidone Iodine Solution

The possible cochlear toxicity of topically applied povidone-iodine solution was investigated in guinea pigs by measuring transiently evoked otoacoustic emissions (TEOAEs). Seven adult pigmented guinea pigs (14 ears) with a normal acoustic pinna reflex were used. After the baseline TEOAE measurements, 0.1mL of povidone-iodine solution was applied transtympanically into the middle ear in the study group. Saline solution and gentamicin were used as negative and positive control, respectively. TEOAE measurements were repeated on the 10th day, and four weeks after the first application. Tympanometric measurements were also carried out for both ears of all animals at the end of the study. Responses in all ears, which had povidone-iodine applied to them, disappeared in a way similar to those recorded in gentamicin-treated ears. Tympanometric measurements at the end of the study showed ’type A’ tympanograms in all ears of all animals. The present study showed that povidone-iodine could have a cochleotoxic effect in guinea pigs. A study in humans with TEOAE before and after middle-ear surgery, where povidone-iodine can reach into the middle-ear cavity, may be useful for evaluating this result for clinical practice.

Audiological findings in glomus tumours

1997 ◽  
Vol 111 (3) ◽  
pp. 218-222 ◽  
Author(s):  
William W. Qiu ◽  
Shengguang S. Yin ◽  
Fred J. Stucker ◽  
Mardjohan Hardjasudarma
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Auditory System ◽  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Cerebellopontine Angle ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Resonance Imaging ◽  
Magnetic Resonance Imaging Mri

AbstractGlomus tumours involving the middle ear and the cerebellopontine angle are reported with emphasis on audiological findings. Magnetic resonance imaging (MRI), angiographic and pathological results are presented. Audiological tests, including impedance audiometry, evoked otoacoustic emissions and auditory brainstem responses, are valuable in evaluation of the effect of glomus tumours on the auditory system as well as their pathological extent.

scholarly journals Fast, Slow, and Steady-State Effects of Contralateral Acoustic Activation of the Medial Olivocochlear Efferent System in Awake Guinea Pigs: Action of Gentamicin

1997 ◽  
Vol 78 (4) ◽  
pp. 1826-1836 ◽  
Author(s):  
Deise Lima da Costa ◽  
Anne Chibois ◽  
Jean-Paul Erre ◽  
Christophe Blanchet ◽  
RENAUD CHARLET de Sauvage ◽  
...  
Keyword(s):  
Steady State ◽  
Time Constant ◽  
Decay Time ◽  
Guinea Pigs ◽  
Round Window ◽  
Broadband Noise ◽  
Decay Time Constant ◽  
Efferent System ◽  
Medial Olivocochlear ◽  
Medial Olivocochlear Efferent System

Lima da Costa, Deise, Anne Chibois, Jean-Paul Erre, Christophe Blanchet, Renaud Charlet de Sauvage, and Jean-Marie Aran. Fast, slow, and steady-state effects of contralateral acoustic activation of the medial olivocochlear efferent system in awake guinea pigs: action of gentamicin. J. Neurophysiol. 78: 1826–1836, 1997. The function of the medial olivocochlear efferent system was observed in awake guinea pigs by recording, in the absence of ipsilateral external acoustic stimulation, the ensemble background activity (EBA) of the VIIIth nerve from an electrode chronically implanted on the round window of one ear. The EBA was measured by calculating the power value of the round window signal in the 0.5- to 2.5-kHz band after digital or analog (active) filtering. This EBA was compared with and without the addition of a low-level broadband noise to the opposite ear. The contralateral broadband noise (CLBN, 55 dB SPL) induced, via the efferent system, a decrease (suppression) of this EBA. With the use of noise bursts of different durations, two components in this suppression could be observed. After the onset of a 1-s CLBN, the power value of the EBA decreased rapidly by 38.0 ± 4.2% (mean ± SD, n = 3), with a latency of <10 ms and a decay time constant of 13.1 ± 1.0 ms (fast effect). At the offset of the 1-s CLBN, EBA came back to prestimulation values with a similar latency and a time constant of 15.5 ± 2.9 ms. During longer CLBN stimulation (≥1 min), EBA presented, after the fast decrease, an additional, slower decrease of 15.6 ± 3.1%, with a delay of 9.8 ± 1.3 s and a decay time constant of 16.1 ± 5.0 s ( n = 12, slow effect), and then remained remarkably constant for as long as observed, i.e., >2 h (steady state). The average global suppression was thus up to 47.8 ± 5.8% of the basal, pre-CLBN-stimulation EBA value. At the offset of the CLBN, EBA returned to pre-CLBN level with fast and slow phases, with, for the slow phase, no delay and a time constant of 32.1 ± 8.1 s. Fast and slow changes in EBA power values were observed after a single injection of gentamicin (GM) at different doses (150, 200, and 250 mg/kg). At 150 and 200 mg/kg, GM progressively and reversibly blocked the rapid effect, but the slow component of the efferent medial suppression remained remarkably unchanged. However, at higher doses both the fast and slow suppressions were totally yet still reversibly blocked. These observations indicate that the medial olivocochlear efferent system exerts sustained influences on outer hair cells and that this effect develops in two different steps that may have different basic cellular mechanisms.

scholarly journals Distinct forms of synaptic plasticity during ascending vs descending control of medial olivocochlear efferent neurons

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Gabriel E Romero ◽  
Laurence O Trussell
Keyword(s):  
Dynamic Range ◽  
Short Term ◽  
Wide Dynamic Range ◽  
Efferent System ◽  
Short Term Plasticity ◽  
Ventral Cochlear Nucleus ◽  
Brainstem Nucleus ◽  
Reflex Arc ◽  
Efferent Neurons ◽  
Medial Olivocochlear

Activity in each brain region is shaped by the convergence of ascending and descending axonal pathways, and the balance and characteristics of these determine neural output. The medial olivocochlear (MOC) efferent system is part of a reflex arc that critically controls auditory sensitivity. Multiple central pathways contact MOC neurons, raising the question of how a reflex arc could be engaged by diverse inputs. We examined functional properties of synapses onto brainstem MOC neurons from ascending (ventral cochlear nucleus, VCN), and descending (inferior colliculus, IC) sources in mice using an optogenetic approach. We found that these pathways exhibited opposing forms of short-term plasticity, with VCN input showing depression and IC input showing marked facilitation. By using a conductance clamp approach, we found that combinations of facilitating and depressing inputs enabled firing of MOC neurons over a surprisingly wide dynamic range, suggesting an essential role for descending signaling to a brainstem nucleus.

Sign in / Sign up

Export Citation Format

Share Document