Multi-tone suppression of distortion-product otoacoustic emissions in humans

Abstract

The purpose of this study was to investigate the combined effect of multiple suppressors. Distortion-product otoacoustic emission (DPOAE) measurements were made in normal-hearing participants. Primary tones had fixed frequencies (f 2 ¼ 4000 Hz; f 1 / f 2 ¼ 1.22) and a range of levels. Suppressor tones were at three frequencies (f s ¼ 2828, 4100, 4300 Hz) and range of levels. Decrement was defined as the attenuation in DPOAE level due to the presence of a suppressor. A measure of suppression called suppressive intensity was calculated by an equation previously shown to fit DPOAE suppression data. Suppressor pairs, which were the combination of two different frequencies, were presented at levels selected to have equal single-suppressor decrements. A hybrid model that represents a continuum between additive intensity and additive attenuation best described the results. The suppressor pair with the smallest frequency ratio produced decrements that were more consistent with additive intensity. The suppressor pair with the largest frequency ratio produced decrements at the highest level that were consistent with additive attenuation. Other suppressor-pair conditions produced decrements that were intermediate between these two alternative models. The hybrid model provides a useful framework for representing the observed range of interaction when two suppressors are combined.

Influence of Instantaneous Compression on Recognition of Speech in Noise with Temporal Dips

“…The implementation of suppression in SHA was based on measurements of DPOAEs with a single suppressor tone and a model that assumed that suppressive effects of multiple suppressor components were additive in the intensity domain. Recent DPOAE data using two suppressor tones have indicated that the suppressive effects of multiple tones are not well described by the simple additive model that was used to mimic the effects of suppression in the design of SHA, but are better described by a hybrid model that involves both additive intensity and additive attenuation models (Sieck et al, 2016). Although future refinements using this model are planned, it is unlikely that these processing changes will affect the ability to listen in noise with temporal dips because suppression mainly affects the spectral characteristics of a signal.…”

“…The suppressive effect was extended to multiple suppressors by assuming that suppression is additive in the intensity domain. This assumption is a simplification and might not describe the ways in which suppressive effects add for all stimulus conditions (see Sieck et al, 2016). Suppose that the total suppressive influence on a tone at f of multiple suppressor tones at f j can be described by…”

Influence of suppression on restoration of spectral loudness summation in listeners with hearing loss

“…The implementation of suppression in SHA was based on measurements of DPOAEs with a single suppressor tone and a model that assumed that suppressive effects of multiple suppressor components were additive in the intensity domain. Recent DPOAE data utilizing two suppressor tones have indicated that the suppressive effects of multiple tones are not well described by the simple additive model that was used to mimic the effects of suppression in the design of the SHA, but are better described by a hybrid model that involves both additive-intensity and additive-attenuation models (Sieck et al, 2016). Another limitation of SHA is that the cross-channel influences due to suppression were based on data from listeners with NH only.…”

“…The suppressive effect was extended to multiple suppressors by assuming that suppression is additive in the intensity domain. This assumption is a simplification and might not describe the ways in which suppressive effects add for all stimulus conditions (see Sieck et al, 2016). Suppose that the total suppressive influence on a tone at f of multiple suppressor tones at f j can be described by summing the individual suppressive intensities of each tone:…”

Peri-intraventricular hemorrhage: Study of the inhibitory effect of auditory efferent pathway

“…Non-invasive investigation of such disorders can be performed through the evaluation of the medial olivocochlear efferent system (MOCES), which originates in the medial nucleus of the superior olivary complex (located in the brainstem) and protrudes over the auditory nerve fibers and the outer hair cells, adjusting the response in the presence of a simultaneous stimulus. Thus, the MOCES can be activated by an inhibitory noise, thereby reducing the contractions of the outer hair cells and, consequently, OAE amplitude levels (6) .…”