Stimulus ratio dependence of low-frequency distortion-product otoacoustic emissions in humans

Christensen, Anders Tornvig; Ordoñez, Rodrigo Pizarro; Hammershøi, Dorte

doi:10.1121/1.4906157

Cited by 5 publications

(16 citation statements)

References 47 publications

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“…Figure 6 shows the measurements from all subjects at each of the three 2 f 1 −f 2 frequencies tested. Shown for context is also data from Christensen et al (2015a). The present and the previous studies included different subjects, except one, and the phase data from the previous study were not reported earlier.…”

Section: Discussionmentioning

confidence: 81%

“…The 2 f 1 −f 2 frequency and the found optimal ratios may be referred to the corresponding f 1 frequencies 163, 282, and 382 Hz and f 2 frequencies 238, 388, and 501 Hz. Christensen et al (2015a) found that it did not make a difference on the optimal ratio to fix f 2 instead of 2 f 1 −f 2 around 246 and 1231 Hz, but those data are arguably not sufficient to justify extrapolation of optimal fixed f 2 data from optimal fixed 2 f 1 −f 2 data.…”

Section: Collective Resultsmentioning

confidence: 92%

“…These criteria left 21 audiometrically normal-hearing subjects in the DPOAE part of the experiment. One female subject included also participated in our previous study (Christensen et al 2015a).…”

Section: Subjectsmentioning

confidence: 99%

“…Time available in the experiment did not allow for further exploration of level effects. The evoked DPOAE level generally increases with the stimulus level, but effects on the optimal ratio are subtle Christensen et al (2015a). Standard levels (black curves) and the custom low-frequency probe (gray curves) during constant pressure stimulation with 65 and 55 dB SPL tones through the probe loudspeakers into a B&K 4157 ear simulator.…”

Section: Stimulus Parametersmentioning

confidence: 99%

“…Standard levels (black curves) and the custom low-frequency probe (gray curves) during constant pressure stimulation with 65 and 55 dB SPL tones through the probe loudspeakers into a B&K 4157 ear simulator. The frequencies of the stimulus tones were selected according to the optimal paradigm of 1.52 ERB (f 2 ) proposed by Christensen et al (2015a). The recordings are made with a the ear simulator microphone and b the probe microphone.…”

Section: Stimulus Parametersmentioning

confidence: 99%

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Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

Christensen

Ordoñez

Hammershøi

2016

JARO

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Physiological noise levels in the human ear canal often exceed naturally low levels of otoacoustic emissions (OAEs) near the threshold of hearing. Low-frequency noise, and electronic filtering to cope with it, has effectively limited the study of OAE to frequencies above about 500 Hz. Presently, a custom-built low-frequency acoustic probe was put to use in 21 normal-hearing human subjects (of 34 recruited). Distortion-product otoacoustic emission (DPOAE) was measured in the enclosed ear canal volume as the response to two simultaneously presented tones with frequencies f and f. The stimulus-frequency ratio f /f was varied systematically to find the "optimal" ratio evoking the largest level at 2 f -f frequencies 87.9, 176, and 264 Hz. No reference data exist in this frequency region. Results show that DPOAE exists down to at least 87.9 Hz, maintaining the bell-shaped dependence on the f /f ratio known from higher frequencies. Toward low frequencies, however, the bell broadens and the optimal ratio increases proportionally to the bandwidth of an auditory filter as defined by the equivalent rectangular bandwidth. The DPOAE phase rotates monotonously as a function of the stimulus ratio, and its slope trend supports the notion of a lack of scaling symmetry in the apex of the cochlea.

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Section: Discussionmentioning

confidence: 81%

Section: Collective Resultsmentioning

confidence: 92%

Section: Subjectsmentioning

confidence: 99%

Section: Stimulus Parametersmentioning

confidence: 99%

Section: Stimulus Parametersmentioning

confidence: 99%

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Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

Christensen

Ordoñez

Hammershøi

2016

JARO

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The eardrums move when the eyes move: A multisensory effect on the mechanics of hearing

Gruters

Murphy

Jenson

et al. 2018

Proc. Natl. Acad. Sci. U.S.A.

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Interactions between sensory pathways such as the visual and auditory systems are known to occur in the brain, but where they first occur is uncertain. Here, we show a multimodal interaction evident at the eardrum. Ear canal microphone measurements in humans (n = 19 ears in 16 subjects) and monkeys (n = 5 ears in three subjects) performing a saccadic eye movement task to visual targets indicated that the eardrum moves in conjunction with the eye movement. The eardrum motion was oscillatory and began as early as 10 ms before saccade onset in humans or with saccade onset in monkeys. These eardrum movements, which we dub eye movement-related eardrum oscillations (EMREOs), occurred in the absence of a sound stimulus. The amplitude and phase of the EMREOs depended on the direction and horizontal amplitude of the saccade. They lasted throughout the saccade and well into subsequent periods of steady fixation. We discuss the possibility that the mechanisms underlying EMREOs create eye movement-related binaural cues that may aid the brain in evaluating the relationship between visual and auditory stimulus locations as the eyes move.reference frame | otoacoustic emissions | middle ear muscles | saccade | EMREO V isual information can aid hearing, such as when lip reading cues facilitate speech comprehension. To derive such benefits, the brain must first link visual and auditory signals that arise from common locations in space. In species with mobile eyes (e.g., humans, monkeys), visual and auditory spatial cues bear no fixed relationship to one another but change dramatically and frequently as the eyes move, about three times per second over an 80°range of space. Accordingly, considerable effort has been devoted to determining where and how the brain incorporates information about eye movements into the visual and auditory processing streams (1). In the primate brain, all of the regions previously evaluated have shown some evidence that eye movements modulate auditory processing [inferior colliculus (2-6), auditory cortex (7-9), parietal cortex (10-12), and superior colliculus (13-17)]. Such findings raise the question of where in the auditory pathway eye movements first impact auditory processing. In this study, we tested whether eye movements affect processing in the auditory periphery.The auditory periphery possesses at least two means of tailoring its processing in response to descending neural control (Fig. 1). First, the middle ear muscles (MEMs), the stapedius and tensor tympani, attach to the ossicles that connect the eardrum to the oval window of the cochlea. Contraction of these muscles tugs on the ossicular chain, modulating middle ear sound transmission and moving the eardrum. Second, within the cochlea, the outer hair cells (OHCs) are mechanically active and modify the motion of both the basilar membrane and, through mechanical coupling via the ossicles, the eardrum [i.e., otoacoustic emissions (OAEs)]. In short, the actions of the MEMs and OHCs affect not only the response to incoming sound but also transmi...

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Distortion Product Otoacoustic Emission Component Behavior as a Function of Primary Frequency Ratio and Primary Level

2022

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Objectives: Distortion product otoacoustic emissions (DPOAEs) are composed of distortion and reflection components. Much is known about the influence of the stimulus frequency ratio (f 2 /f 1 ) on the overall/composite DPOAE level. However, the influence of f 2 /f 1 on individual DPOAE components is not as well examined. The goals of this pilot study were to systematically evaluate the effects of f 2 /f 1 on DPOAE components in clinically normal-hearing young adult ears. To extend the limited reports in the literature, this examination was carried out over an extended frequency range using two stimulus-level combinations.Design: DPOAEs were recorded from seven normal-hearing, young adult ears for f 2 frequencies between 0.75 and 16 kHz over a range of f 2 /f 1 using two stimulus-level combinations. The distortion (DPOAE D ) and reflection (DPOAE R ) components were separated using an inverse fast Fourier transform algorithm. Optimal ratios for the composite DPOAE and DPOAE components were determined from smoothed versions of level versus ratio functions in each case. Results:The optimal ratio for the composite DPOAE level increased with stimulus level and decreased as a function of frequency above 1 kHz. The optimal ratios for the DPOAE components followed a similar trend, decreasing with increasing frequency. The optimal ratio for DPOAE D was generally higher than that for DPOAE R . The overall level for DPOAE D was greater than that of DPOAE R , both decreasing with increasing frequency. DPOAE R , but not DPOAE D , became unrecordable above the noise floor at the higher frequencies.Conclusions: DPOAE components behave similarly but not identically as a function of f 2 /f 1 . The ear canal DPOAE is generally dominated by DPOAE D . The behavior of DPOAE D as a function of f 2 /f 1 is entirely consistent with known properties of cochlear mechanics. The behavior of DPOAE R is more variable across ears, perhaps reflective of the increased number of parameters that influence its final form. Attempting to use an f 2 /f 1 that would allow a greater bias of the ear canal DPOAE toward one component or the other does not appear to be practical.

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Stimulus ratio dependence of low-frequency distortion-product otoacoustic emissions in humans

Cited by 5 publications

References 47 publications

Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

Distortion-Product Otoacoustic Emission Measured Below 300 Hz in Normal-Hearing Human Subjects

The eardrums move when the eyes move: A multisensory effect on the mechanics of hearing

Distortion Product Otoacoustic Emission Component Behavior as a Function of Primary Frequency Ratio and Primary Level

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