scholarly journals Bilateral spontaneous otoacoustic emissions show coupling between active oscillators in the two ears

2018 ◽  
Author(s):  
Yuttana Roongthumskul ◽  
Daibhid O Maoileidigh ◽  
Albert Hudspeth
Keyword(s):  
Sound Localization ◽  
Otoacoustic Emissions ◽  
Nonlinear Oscillators ◽  
Acoustic Stimulation ◽  
Strongly Correlated ◽  
Spontaneous Otoacoustic Emissions ◽  
Acoustic Coupling ◽  
Tokay Gecko ◽  
Active Processes ◽  
The Relationship

Spontaneous otoacoustic emissions (SOAEs) are weak sounds that emanate from the ears of tetrapods in the absence of acoustic stimulation. These emissions are an epiphenomenon of the active process of the inner ear, which enhances the sensitivity of the auditory system to weak sounds, but their mechanism of production remains a matter of debate. To understand the relationship between SOAEs that we recorded simultaneously from the two ears of the tokay gecko, we developed a mathematical model of the eardrums as noisy nonlinear oscillators coupled by the air within the mouth of a lizard. We found that binaural emissions could be strongly correlated: some emissions occurred at the same frequency in both ears and were highly synchronized. Suppression of the emissions in one ear often changed the amplitude or shifted the frequency of emissions in the other. Decreasing the frequency of emissions from one ear by lowering its temperature usually reduced the frequency of the contralateral emissions. By according with the model, the results indicate that some SOAEs are generated bilaterally through acoustic coupling across the oral cavity. The model predicts that sound localization through the acoustic coupling between ears is influenced by the active processes of both ears.

scholarly journals Calcium Modulates the Frequency and Amplitude of Spontaneous Otoacoustic Emissions in the Bobtail Skink

2004 ◽  
Vol 92 (5) ◽  
pp. 2685-2693 ◽  
Author(s):  
Geoffrey A. Manley ◽  
Ulrike Sienknecht ◽  
Christine Köppl
Keyword(s):  
Hair Cell ◽  
Hair Cells ◽  
Otoacoustic Emissions ◽  
Calcium Concentration ◽  
Chelating Agent ◽  
Lizard Species ◽  
Spontaneous Otoacoustic Emissions ◽  
Active Processes

Active processes in the inner ear of lizards can be monitored using spontaneous otoacoustic emissions (SOAE) measured outside the eardrum. In the Australian bobtail lizard, SOAE are generated by an active motility process in the hair-cell bundle. This mechanism has been shown to be sensitive to the calcium-chelating agent 1,2-bis(o-aminophenoxy)ethane- N,N,N′,N′-tetraacetic acid and is presumed to be related to the calcium-sensitive transduction-channel motor implicated in other nonmammalian hair cell systems. In studies of frog saccular and turtle auditory papillar hair cells in vitro, the frequency and amplitude of bundle oscillations depend on the concentration of calcium in the bathing solutions. In the present study, the calcium concentration in the endolymph was changed in vivo in the Australian bobtail lizard Tiliqua rugosa, and SOAE were monitored. Glass pipettes with large tips and containing different calcium concentrations in their fluids were introduced into scala media, and their contents were allowed to passively flow into the endolymph. Low calcium concentrations resulted in a downward shift in the frequency of SOAE spectral peaks and generally an increase in their amplitudes. Calcium concentrations >2 mM resulted in increases in frequency of SOAE peaks and generally a loss in amplitude. These frequency shifts were consistent with in vitro data on the frequencies and amplitudes of spontaneous oscillation of hair cell bundles and thus also implicate calcium ions in the generation of active motility in nonmammalian hair cells. The data also suggest that in this lizard species, the ionic calcium concentration in the cochlear endolymph is ≥1 mM.

Effect of middle-ear effusion on otoacoustic emissions

2002 ◽  
Vol 116 (10) ◽  
pp. 794-799 ◽  
Author(s):  
Sang W. Yeo ◽  
Shi-Nae Park ◽  
Yong Soo Park ◽  
Byung Do Suh
Keyword(s):  
Middle Ear ◽  
Otoacoustic Emissions ◽  
Otitis Media With Effusion ◽  
Geometric Mean ◽  
Bone Conduction ◽  
Middle Ear Effusion ◽  
Spontaneous Otoacoustic Emissions ◽  
Distortion Product ◽  
The Relationship ◽  
Ear Effusion

Because otoacoustic emissions (OAEs) are transmitted from the cochlea to the ear canal via the middle ear, the transmission properties of the middle ear directly influence OAEs’ characteristics. In general, middle-ear effusion (MEE) reduces measured emission amplitudes and sometimes eliminates the response entirely. The purpose of this study was to establish the relationship between the conduction of the middle ear and OAEs’ properties and to elucidate the effect of middle-ear effusion on detecting OAEs’. Spontaneous otoacoustic emissions (SOAEs), transiently evoked otoacoustic emissions (TEOAEs) and distortion product otoacoustic emissions (DPOAEs) were recorded from 44 normal ears and 32 ears with middle-ear effusion. DPOAEs were collected in two basic forms consisting of distortion product audiograms (DP grams) and input-output (I-O) functions, elicited by two primary tones F1 and F2 and varying geometric mean frequencies between 1–6 kHz. The results of air and bone conduction hearing levels in pure tone audiogram were also analysed. In 21 ears out of 32 otitis media with effusion (OME) ears, SOAEs were absent. In the 28 ears with middle-ear effusion, the response and wave reproducibility were diminished, and in the 17 ears with middle-ear effusion, the DP gram was diminished or eliminated. In particular, I-O function curves at 3 kH and 4 kHz were diminished by the primary tones of 45 and 55 dB under the condition of MEE. The SOAEs, TEOAEs and DPOAEs (DP gram and I-O function curve) are highly reliable and useful tests for monitoring changes in middle-ear condition in children with OME and in predicting the course of OME.

scholarly journals CHANGES IN HUMAN SPONTANEOUS OTOACOUSTIC EMISSIONS WITH CONTRALATERAL ACOUSTIC STIMULATION

1993 ◽  
Vol 96 (6) ◽  
pp. 922-930,1047 ◽  
Author(s):  
MASAAKI KASHIWAMURA ◽  
NOBUKIYO SATOH ◽  
SATOSHI FUKUDA ◽  
MITSUGU KAWANAMI ◽  
EIJI CHIDA ◽  
...  
Keyword(s):  
Otoacoustic Emissions ◽  
Acoustic Stimulation ◽  
Spontaneous Otoacoustic Emissions ◽  
Contralateral Acoustic Stimulation
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