Contralateral Suppression of Otoacoustic Emissions: Working Towards a Simple Objective Frequency Specific Test for Hearing Screening

Wolter, Nikolaus E.; Harrison, Robert V.; James, Adrian

doi:10.5772/34496

Cited by 1 publication

(8 citation statements)

References 84 publications

(123 reference statements)

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“…It is assumed that MEMR-related inhibition would not exhibit such properties [Warren and Liberman, 1989]. Work done in our laboratory using real-time measurement of CS-DPOAE in chinchillas has demonstrated that the greatest magnitude of inhibition is achieved when the contralateral tone approximates the DPOAE f 2 stimulus frequency when specific frequencies were used in the range from 1.6 to 7.7 kHz, confirming that CS-DPOAE shows f 2 frequency specificity [Wolter et al, 2012]. Previously unpublished data in figure 2 demonstrate that contralateral inhibition of DPOAE at f 2 = 4.4 kHz is greatest when the contralateral tone approximates f 2 = 4.4 kHz (black symbols).…”

mentioning

confidence: 67%

“…In this figure, only 2 frequencies, f 2 = 4.4 kHz (black line) and f 2 = 7.7 kHz (dashed line), are shown for the purposes of clarity. All frequencies can be seen in Wolter et al [2012]. The magnitude of suppression was greatest when the contralateral tone approximated the f 2 frequency.…”

Section: Contralateral Acoustic Stimulusmentioning

confidence: 95%

“…The distortion product recorded was the 2f 1 -f 2 , from primary tones at an f 2 of 4.4 kHz (f 2 /f 1 = 1.22) and intensity levels of L 1 = 65 dB SPL and L 2 = 55 dB SPL. We concentrated on these particular stimuli as they had been found to evoke the maximum response in our previous work in chinchillas [Wolter et al, 2012]. The levels chosen to give optimal DPOAE were determined from input/output functions of primary level versus signal level.…”

Section: Real-time Dpoae Measurementmentioning

confidence: 99%

“…The levels chosen to give optimal DPOAE were determined from input/output functions of primary level versus signal level. For this experiment we focused on f 2 = 4.4 kHz because it was the most robust and reliable response in our previous work with the chinchilla [Wolter et al, 2012].…”

Section: Real-time Dpoae Measurementmentioning

confidence: 99%

“…A 550-ms white-noise stimulus was repeated every 1,223 ms (Cool Edit 2000; Syntrillium Software Corporation, Phoenix, Contralateral suppression of DPOAE shows frequency specificity, but this is lost for low-frequency stimuli. Real-time DPOAE were recorded at 2f 1 -f 2 from primary tones which were set at f 2 / f 1 = 1.22 for specific frequencies between 0.6-17 kHz and intensity levels of L 1 = 65 dB SPL and L 2 = 55 dB SPL [Wolter et al, 2012]. In this figure, only 2 frequencies, f 2 = 4.4 kHz (black line) and f 2 = 7.7 kHz (dashed line), are shown for the purposes of clarity.…”

Section: Contralateral Acoustic Stimulusmentioning

confidence: 99%

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Separating the Contributions of Olivocochlear and Middle Ear Muscle Reflexes in Modulation of Distortion Product Otoacoustic Emission Levels

2013

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Objectives: Mediated by the medial olivocochlear system (MOCS), distortion product otoacoustic emission (DPOAE) levels are reduced by presentation of contralateral acoustic stimuli. Such acoustic signals can also evoke a middle ear muscle reflex (MEMR) that also attenuates recorded DPOAE levels. Our aim is to clearly differentiate these two inhibitory mechanisms and to analyze each separately, perhaps allowing the development of novel tests of hearing function. Methods: DPOAE were recorded in real time from chinchillas with normal auditory brainstem response thresholds and middle ear function. Amplitude reduction and its onset latency caused by contralateral presentation of intermittent narrow-band noise (NBN) were measured. Stapedius and tensor tympani muscle tendons were divided without disturbing the ossicular chain, and DPOAE testing was repeated. Results: Peak reduction of (2f₁ - f₂) DPOAE levels occurred when the center frequency of contralateral NBN approximated the primary tone f₂, indicating an f₂-frequency-specific response. For a 4.5-kHz centered NBN, DPOAE (f₂ = 4.4 kHz) inhibition was 0.1 dB (p < 0.001). This response remained present after tendon division, consistent with an MOCS origin. Low-frequency NBN (center frequency: 0.5 kHz) reduced otoacoustic emission levels (0.1 dB, p < 0.001) across a wide range of DPOAE frequencies. This low-frequency response was abolished by division of the middle ear muscle tendons, clearly indicating MEMR involvement. Conclusions: Following middle ear muscle tendon division, DPOAE inhibition by contralateral stimuli approximating the primary tone f₂ persists, whereas responses evoked by lower contralateral frequencies are abolished. This distinguishes the different roles of the MOCS (f₂ frequency specific) and MEMR (low frequency only) in contralateral modulation of DPOAE. This analysis helps clarify the pathways involved in an objective test that might have clinical benefit in the testing of neonates.

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mentioning

confidence: 67%

Section: Contralateral Acoustic Stimulusmentioning

confidence: 95%

Section: Real-time Dpoae Measurementmentioning

confidence: 99%

Section: Real-time Dpoae Measurementmentioning

confidence: 99%

Section: Contralateral Acoustic Stimulusmentioning

confidence: 99%

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