Test/retest repeatability of effect contralateral acoustic stimulation on the magnitudes of distortion product ototacoustic emissions

2012 ◽  
Vol 123 (2) ◽  
pp. 463-471 ◽  
Author(s):  
U. Ajith Kumar ◽  
Raksha Methi ◽  
M. C. Avinash
Keyword(s):  
Acoustic Stimulation ◽  
Distortion Product ◽  
Contralateral Acoustic Stimulation

scholarly journals Changes in Distortion Product Otoacoustic Emission Caused by Contralateral Broadband Noise

2015 ◽  
Vol 39 (1) ◽  
pp. 125-138 ◽  
Author(s):  
Edward Ozimek ◽  
Andrzej Wicher
Keyword(s):  
Otoacoustic Emission ◽  
Acoustic Stimulation ◽  
Wide Frequency Range ◽  
Broadband Noise ◽  
Distortion Product Otoacoustic Emission ◽  
Frequency Range ◽  
Distortion Product ◽  
Stimulation Level ◽  
Contralateral Acoustic Stimulation ◽  
The Mean

Abstract The main purpose of this investigation was to measure the effect of contralateral acoustic stimulation (CAS) on distortion product otoacoustic emission (DPOAE) in twenty human ears, for a ratio of primary tones f2/f1 = 1.22 and a wide frequency range of f2 (1.4-9 kHz), for two intensity levels of primary tones (L1 = 60 dB SPL; L2 = 50 dB SPL and L1 = 70 dB SPL; L2 = 60 dB SPL) and two intensity levels of CAS (50 and 60 dB SPL). It was found that in the presence of CAS, in the majority of cases the DPOAE level decreased (suppression), but it might also increase (enhancement) or remain unchanged depending on the frequency. The mean suppression level of the component of the frequency fDP = 2f1 f2 might be approximated by a linearly decreasing function of the f2 frequency of primary tones. The slope of this function was negative and increased with an increase of the contralateral stimulation level. The higher was the contralateral noise level the greater was the suppression. For the fDP level below about 15 dB SPL, suppression was observed in a substantial number of measurement cases (in about 85% of all measured cases on average). When the fDP level was higher than 15 dB SPL, only suppression (not enhancement) was observed.

scholarly journals Stability of the Medial Olivocochlear Reflex as Measured by Distortion Product Otoacoustic Emissions

2015 ◽  
Vol 58 (1) ◽  
pp. 122-134 ◽  
Author(s):  
Srikanta K. Mishra ◽  
Carolina Abdala
Keyword(s):  
Acoustic Stimulation ◽  
Normal Hearing ◽  
Term Stability ◽  
Long Term Stability ◽  
Distortion Product ◽  
Contralateral Acoustic Stimulation ◽  
Short And Long Term ◽  
Medial Olivocochlear ◽  
Fine Resolution

PurposeThe purpose of this study was to assess the repeatability of a fine-resolution, distortion product otoacoustic emission (DPOAE)–based assay of the medial olivocochlear (MOC) reflex in normal-hearing adults.MethodData were collected during 36 test sessions from 4 normal-hearing adults to assess short-term stability and 5 normal-hearing adults to assess long-term stability. DPOAE level and phase measurements were recorded with and without contralateral acoustic stimulation. MOC reflex indices were computed by (a) noting contralateral acoustic stimulation-induced changes in DPOAE level (both absolute and normalized) at fine-structure peaks, (b) recording the effect as a vector difference, and (c) separating DPOAE components and considering a component-specific metric.ResultsAnalyses indicated good repeatability of all indices of the MOC reflex in most frequency ranges. Short- and long-term repeatability were generally comparable. Indices normalized to a subject's own baseline fared best, showing strong short- and long-term stability across all frequency intervals.ConclusionsThese results suggest that fine-resolution DPOAE-based measures of the MOC reflex measured at strategic frequencies are stable, and natural variance from day-to-day or week-to-week durations is small enough to detect between-group differences and possibly to monitor intervention-related success. However, this is an empirical question that must be directly tested to confirm its utility.

Contralateral Acoustic Stimulation Modulates Low-Frequency Biasing of DPOAE: Efferent Influence on Cochlear Amplifier Operating State?

2009 ◽  
Vol 101 (5) ◽  
pp. 2362-2371 ◽  
Author(s):  
Cornelius Abel ◽  
Anna Wittekindt ◽  
Manfred Kössl
Keyword(s):  
Otoacoustic Emissions ◽  
Low Frequency ◽  
Acoustic Stimulation ◽  
Operating Point ◽  
Cochlear Amplifier ◽  
Contralateral Noise ◽  
Distortion Product ◽  
Contralateral Acoustic Stimulation ◽  
Olivocochlear System ◽  
Cas A

The mammalian efferent medial olivocochlear system modulates active amplification of low-level sounds in the cochlea. Changes of the cochlear amplifier can be monitored by distortion product otoacoustic emissions (DPOAEs). The quadratic distortion product f2–f1 is known to be sensitive to changes in the operating point of the amplifier transfer function. We investigated the effect of contralateral acoustic stimulation (CAS), known to elicit efferent activity, on DPOAEs in the gerbil. During CAS, a significant increase of the f2–f1 level occurred already at low contralateral noise levels (20 dB SPL), whereas 2f1–f2 was much less affected. The effect strength depended on the CAS level and as shown in experiments with pure tones on the frequency of the contralateral stimulus. In a second approach, we biased the position of the cochlear partition and thus the cochlear amplifier operating point periodically by a ipsilateral low-frequency tone, which resulted in a phase-related amplitude modulation of f2–f1. This modulation pattern was changed considerably during contralateral noise stimulation, in dependence on the noise level. The experimental results were in good agreement with a simple model of distortion product generation and suggest that the olivocochlear efferents might change the operating state of cochlear amplification.

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