?Single-generator- Distorsionsprodukte? (sgDPOAE)

Pk, Plinkert; Heitmann, J.; Waldmann, Bernd

doi:10.1007/s001060050173

Cited by 7 publications

(1 citation statement)

References 14 publications

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“…With more precise knowledge about DPOAE D and DPOAE R behavior, could a clinical protocol be designed to bias the ear canal signal towards one of the components thereby mitigating the problem of uncontrolled component mixing? Such biasing of the ear canal DPOAE by eliminating the reflection component has been attempted before, either by deploying a suppressor tone (Brown & Kemp 1984; Plinkert et al 1997) or using post-hoc component separation techniques as was attempted here (Johnson et al 2006b). However, both techniques pose practical challenges of imprecision and extended test time (see Shaffer et al 2006 for a detailed discussion).…”

Section: Discussionmentioning

confidence: 99%

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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Section: Discussionmentioning

confidence: 99%

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

2022

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Fine structure of distortion product otoacoustic emissions: its dependence on age and hearing threshold and clinical implications

Wagner

Plinkert

Vonthein

et al. 2008

Eur Arch Otorhinolaryngol

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Distortion product otoacoustic emissions (DPOAE) are routinely used in audiological diagnostics. When the stimulus frequencies f1 and f2 are varied in small steps, distinct non-monotonicities (peaks and valleys) in DPOAE level versus frequency functions can be observed. This so-called DPOAE fine structure (FS) is supposed to be the result of physiological interferences between two different cochlear sources which generate the DPOAE signal. Although FS can complicate interpretations with respect to cochlear functional status at the primary source near f2, its presence might also be relevant in clinical audiological diagnostics. It is therefore of interest to determine FS prevalence and its dependence on age, frequency and hearing threshold. First, it was screened for FS using two tone stimulation (L1/L2 = 55/45 dB SPL, f2/f1 = 1.22) and frequency steps of 40 Hz in the frequency range of 1.8-4.2 kHz. DPOAE (2f1 - f2) were then recorded in 1/3 octave-bands centered around f2 = 2, 3 and 4 kHz with a frequency resolution of 12.5, 20 and 25 Hz, respectively, both with and without a third stimulus (L3 = 45 dB SPL, f3 = 2f1 - f2 + 25 Hz) which was supposed to act as a suppressor of FS. Results of measurements in 102 human individuals from a mixed patient population are reported. Prevalence of DPOAE and FS in a specific frequency range, (i.e. 2, 3, or 4 kHz) was classified into five categories: I) distinct FS within the respective frequency range, II) "single dip" in DP-gram, III) "flat" DP-gram well above noise floor but no distinct FS, IV) DPOAE near noise floor with "irregular responses", and V) no DPOAE measurable. The prevalence of the categories was set in relation to the subject's age and the audiometric threshold at the corresponding center frequency. The estimated probability for a FS (category I and II) was 50-80% if hearing threshold was better than 10 dB HL at the corresponding center frequency. FS prevalence strongly decreased with increasing hearing loss (P < 0.0001). There was no statistically significant age effect (P = 0.088). In more than 50% of the subjects with a behavioral hearing threshold of 10 dB HL or better, a distinct FS near the according frequency was detected, given the presented measurement conditions. While further research is directed at optimal suppression of the second cochlear source of DPOAE and thereby of FS in order to obtain information about the cochlear status near f2 only, the evaluation of FS itself may be clinically useful for monitoring subtle cochlear changes, e.g. during exposure to ototoxic substances or noise.

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Comparison of distortion product otoacoustic emissions and pure tone audiometry in occupational screening for auditory deficit due to noise exposure

Wooles

Mulheran

Bray³

et al. 2015

J. Laryngol. Otol.

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No clinically relevant predictive relationship between distortion product otoacoustic emission amplitude and pure tone audiometry threshold was apparent. These results do not support the replacement of pure tone audiometry with distortion product otoacoustic emissions in screening. Distortion product otoacoustic emissions at frequencies associated with elevated pure tone audiometry thresholds are evidence of intact outer hair cell function, suggesting that sites distinct from these contribute to auditory deficit following ototrauma.

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?Single-generator- Distorsionsprodukte? (sgDPOAE)

Cited by 7 publications

References 14 publications

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

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

Fine structure of distortion product otoacoustic emissions: its dependence on age and hearing threshold and clinical implications

Comparison of distortion product otoacoustic emissions and pure tone audiometry in occupational screening for auditory deficit due to noise exposure

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