2f1-f2 distortion product otoacoustic emission (DPOAE) input/output functions were recorded in 796 ears with sensorineural hearing loss at up to 50 frequencies between 500 Hz and 8 kHz in a wide level range from L2 = 20 to L2 = 65 dB SPL at up to 10 levels ("scissor paradigm", ...

Distortion product otoacoustic emissions emitted by the cochlea at 2f1-f2 in response to pairs of pure tones at f1 and f2 (DPOAE) form a class of otoacoustic emissions and as such, are viewed as a reliable tool for screening outer hair cell (OHC) dysfunctions on a pass/fail basis. However, the ...

In recent years, evidence has accumulated in support of a two-source model of distortion product otoacoustic emissions (DPOAEs). According to such models DPOAEs recorded in the ear canal are associated with two separate sources of cochlear origin. It is the interference between the contributions from the two sources that gives ...

In distortion product otoacoustic emission (DPOAE) measurements the ear is stimulated with two pure tones f1 and f2. To maximize DPOAE levels and hence increase the sensitivity of DPOAE measurements, the separation of the two primary tone levels has been shown to play a crucial role. In contrast to conventionally ...

Transient evoked otoacoustic emissions (TEOAEs) have been analyzed in a population of 134 ears, divided into three classes: (1) nonexposed ears in bilaterally normal hearing subjects, (2) audiometrically normal ears of subjects exposed to noise and affected by unilateral high-frequency (f>3 kHz) hearing loss in the contralateral ear, and (3) ...

A detailed comparison of 2f(1)-f(2) distortion product otoacoustic emission (DPOAE) level shifts (LS) and auditory brainstem response (ABR) threshold shifts with noise-induced histopathology was conducted in chinchillas. DPOAE levels (i.e., L(1) and L(2)) at f(1) and f(2), respectively, ranged from 55-75 dB sound pressure level (SPL), with f(2)/f(1)=1.23, 6 points/octave, ...

Measurements of DPOAE level in the presence of a suppressor were used to describe a pattern that is qualitatively similar to population studies in the auditory nerve and to behavioral studies of upward spread of masking. DPOAEs were measured in the presence of a suppressor (f3) fixed at either 2.1 ...

Sonoluminescing single bubbles driven simultaneously by two harmonic frequencies were recently reported to increase the maximum light output up to a factor of 3 with respect to single mode excitation. In this paper, experimental and numerical results on single-bubble sonoluminescence (SBSL) in an air/water system using the fundamental mode of ...

Computer simulations of bubble oscillations are performed under conditions of multibubble sonoluminescence (MBSL) in water for various ultrasonic frequencies. The range of the ambient bubble radius for sonoluminescing bubbles narrows as the ultrasonic frequency increases; at 20 kHz it is 0.1-100 microm while at 1 MHz it is 0.1-3 microm. ...

Emission characteristics (at 2f1-f2) are measured in Mongolian gerbil as a function of the independent variation of all four stimulus parameters, the frequencies (f1 and f2) and the intensities (L1 and L2) of the two stimulus tones. The main five-dimensional display chosen is a logarithmic grid of frequencies, where for ...

In order to test the frequency specificity of the efferent suppressive effect on otoacoustic emissions, changes in the 2f1-f2 distortion product otoacoustic emission (DPOAE) levels induced by contralateral stimuli of different spectra were measured in 10 normally hearing adults. Three types of contralateral stimuli were used: (i) a set of ...

The inner ear contains receptor cells that oscillate spontaneously, generating waves that propagate backward in the cochlea, ultimately causing sound to be radiated into the ear canal--the spontaneous otoacoustic emissions (SOAEs). Except in rare conditions, these internally generated signals appear to go unheard. The intensity of SOAEs admittedly hovers near ...

The ear is the organ used for hearing and maintaining equilibrium. In the inner ear, the vestibular system is responsible for the sense of balance. The main organs of the vestibular system are the semicircular canals, the saccule, and the utricle. Within each of the vestibular organs, sensory receptors in ...

Light emission spectra were measured from separate Pd particles excited by the passage of electrical current through them. As the particle size decreases or input power increases the intensities of peaks increase more strongly in the high-energy part of the spectra than in the low-energy part. Moreover, new peaks can ...

HYPOTHESIS: To understand cochlear dysfunction and the recovery pattern of the cochlea after acute electrical injury. BACKGROUND: The cochlea is believed to be more vulnerable to direct current than to alternating current. However, the damage-and frequency-specific recovery characteristics of the cochlea have not been well described. METHODS: Baseline distortion product ...

Electrically evoked otoacoustic emissions (EEOAEs) can be elicited from the chicken inner ear. Since lesion studies implicate hair cells are the source of EEOAEs, we hypothesized that acoustic stimuli would modulate EEOAE amplitude at cochlear locations where the acoustic and electrical stimuli overlap. To assess this interaction, EEOAEs were measured ...

In this paper, a new method is introduced to derive a cochlear transducer function from measuring distortion product otoacoustic emissions (DPOAEs). It is shown that the cubic difference tone (CDT, 2f1-f2) is produced from the odd-order terms of a power series that approximates a nonlinear function characterizing cochlear transduction. Exploring ...

Distortion product otoacoustic emissions (DPOAE) elicited by tones below 60-70 dB sound pressure level (SPL) are significantly more sensitive to cochlear insults. The vulnerable, low-level DPOAE have been associated with the postulated active cochlear process, whereas the relatively robust high-level DPOAE component has been attributed to the passive, nonlinear macromechanical ...

Spontaneous otoacoustic emissions (SOAEs) are accepted as being indicators of an active process in the inner ear and have been observed in all groups of land vertebrates. Previous studies have indicated that there may be more than one cellular substrate driving the active processes in different groups of vertebrates. To ...

This study investigated the effects of noise on typical transient-evoked oto-acoustic emission (TEOAE) pass/fail criteria. Different levels of synthesised noise were added to one TEOAE signal, to determine the relationship between the signal-to-noise ratio (SNR) and typical TEOAE parameters: reproducibility, TEOAE level and corrected TEOAE level. Results showed that, with ...

The influence of the frequency ratio f(2)/f(1) of two pure-tone stimuli on the distortion-product otoacoustic emissions (DPOAEs) at 2f(1)-f(2) was assessed in 14 hearing-impaired human ears exhibiting a narrow audiometric notch at 4 kHz, whereas 11 normally hearing ears served as controls. A fixed-f(2) paradigm was used, with f(2) values ...

The aim of this study was to measure contralateral suppression of distortion product otoacoustic emissions (DPOAE) in real time. A total of 10 human subjects were studied with a novel device to record DPOAE without signal time averaging, using digital narrow band pass filtering. Real time DPOAE levels were recorded ...

DPOAE sources are modeled by intermodulation distortion generated near the f2 place and a reflection of this distortion near the DP place. In a previous paper, inverse fast Fourier transforms (IFFTs) of DPOAE filter functions in normal ears were consistent with this model [Konrad-Martin et al., J. Acoust. Soc. Am. ...

A new method for direct pure-tone threshold estimation from input/output functions of distortion product otoacoustic emissions (DPOAEs) in humans is presented. Previous methods use statistical models relating DPOAE level to hearing threshold including additional parameters e.g., age or slope of DPOAE I/O-function. Here we derive a DPOAE threshold from extrapolated ...

A series of detailed experiments is described that investigates how a transient evoked otoacoustic emission (TEOAE) recorded to one-click stimulus is affected by the presence of a variable number of preceding clicks presented over a range of interclick intervals (ICIs). Part of the rationale was to determine if the resulting ...

With the discovery of otoacoustic emissions (OAEs), the efferent cochlear system has become accessible for investigation in humans. Recently, it has been suggested that contralateral sound activated OAE efferent suppression may provide an early indication of auditory damage due to exposure to noise. In this study, OAE efferent suppression in ...

A test based on measures of distortion-product otoacoustic emissions (DPOAEs) was developed in lightly anesthetized guinea pigs and alert rabbits to assess the effective activation or functional "strength" of the cochlear efferent system. The multifrequency method described here used the DP-gram frequency function to evaluate the fast component of the ...

We develop an objective, noninvasive method for determining the frequency selectivity of cochlear tuning at low and moderate sound levels. Applicable in humans at frequencies of 1 kHz and above, the method is based on the measurement of stimulus-frequency otoacoustic emissions and, unlike previous noninvasive physiological methods, does not depend ...

As part of the project LBA-EUSTACH (European Studies on Trace gases and Atmosphere Chemistry as a contribution to the Large- Scale Biosphere-Atmosphere experiment in Amazonia), we examined the diel pattern of isoprenoid exchange in the wet season of 1999 at a remote field site in Rondonia, Brazil. The emission pattern ...

It is widely assumed that the distortion characteristics of the cochlea are uniform across its length, or at least across some portion of its length. For each distortion product otoacoustic emission (DPOAE) input/output (I/O) function across frequency, there is a corresponding cochlear I/O function defined over the cochlear source region. ...

Distortion-product otoacoustic emissions (DPOAEs) at 2f1-f2 can be suppressed by the introduction of a third "suppressor" tone. Plotting the suppression of the DPOAE level against the changing frequency and level of the suppressor produces frequency-tuning functions referred to as suppression tuning curves (STCs). The dominant features of STCs, including their ...

Experimental measurements of the otoacoustic emission (OAE) latency of adult subjects have been obtained, as a function of frequency, by means of wavelet time-frequency analysis based on the iterative application of filter banks. The results are in agreement with previous OAE latency measurements by Tognola et al. [Hear. Res. 106, ...

Distortion product otoacoustic emission (DPOAE) levels in response to primary pairs (f2 = 2 or 4 kHz, L2 ranging from 20 to 60 dB SPL, L1 = 0.4L2 + 39 dB) were measured with and without suppressor tones (f3), which varied from 1 octave below to 1/2 octave above f2, ...

For low and medium sound pressure levels (SPLs), the amplitude of the distortion product otoacoustic emission (DPOAE) recorded from guinea pigs at the 2f1-f2 frequency is maximal when f2/f1 approximately 1.23 and decreases for lower and higher f2/f1 ratios. The high-ratio slope of the DPOAE dependence on the ratio of ...

The noctuoid moth Empyreuma affinis has a simple tympanal organ with only two receptor cells attached to the eardrum. As in vertebrates, the growth of distortion-product otoacoustic emissions (DPOAE) with increasing stimulus level is characterized by two distinct components. An initial increase of DPOAE level for f(2) levels in the ...

Hearing relies on active filtering to achieve exquisite sensitivity and sharp frequency selectivity. In a quiet environment, the ears of many vertebrates become unstable and emit one to several tones. These spontaneous otoacoustic emissions, the most striking manifestation of the inner ear's active process, must result from self-sustained mechanical oscillations ...

Distortion-product otoacoustic emissions (DPOAEs) elicited with stimulus frequencies less than or equal to 8 kHz have been used in hearing clinics to assess whether the middle ear and cochlea are normal, but high-frequency hearing (>4 kHz) is most vulnerable to cochlear pathology. It might prove useful to measure DPOAEs with ...

The cochlear amplifier shows level-dependent function and works optimally at low levels. For this reason, manipulation of stimulus level is a route through which the human cochlear amplifier can be investigated in a noninvasive manner. Distortion product otoacoustic emissions (DPOAEs) evoked as a function of stimulus level provide a tool ...

Similarities and differences in distortion-product otoacoustic emissions (DPOAEs) among four Food and Drug Administration (FDA) approved devices were assessed quantitatively. DPOAEs were recorded from 42 adult subjects (84 ears) ranging in age from 19 to 40 years. All subjects had hearing thresholds of 20 dB HL or better for the ...

Activation of ipsilaterally responsive olivocochlear (OC) neurons by sound produces rapid, post-onset alterations in the 2f1-f2 distortion product otoacoustic emission (DPOAE). The present study investigates the frequency and level dependence of this ipsilateral OC effect in the anesthetized guinea pig, compares its magnitude and sign to OC effects elicited by ...

Click-evoked and stimulus frequency otoacoustic emissions (CEOAEs and SFOAEs, respectively) were studied in humans during and after postural changes. The subjects were tilted from upright to a recumbent position (head down 30 deg) and upright again. Due to the downward posture change, CEOAEs showed a phase increase (80 deg at ...

In mammals, environmental sounds stimulate the auditory receptor, the cochlea, via vibrations of the stapes, the innermost of the middle ear ossicles. These vibrations produce displacement waves that travel on the elongated and spirally wound basilar membrane (BM). As they travel, waves grow in amplitude, reaching a maximum and then ...

Basilar-membrane and auditory-nerve responses to impulsive acoustic stimuli, whether measured directly in response to clicks or obtained indirectly using cross- or reverse-correlation and/or Fourier analysis, manifest a striking symmetry: near-invariance with stimulus intensity of the fine time structure of the response over almost the entire dynamic range of hearing. This ...

Little information is available on product use by consumers, which severely hampers exposure estimation for consumer products. This article describes actual contact with several consumer products, specifically dishwashing detergents, cleaning products, and hair styling products. How and where products are handled, as well as the duration, frequency, and amount of ...

Primary and secondary sources combine to produce the 2f1-f2 distortion product otoacoustic emission (DPOAE) measured in the ear canals of humans. DPOAEs were obtained in nine normal-hearing subjects using a fixed-f2 paradigm in which f1 was varied. The f2 was 2 or 4 kHz, and absolute and relative primary levels ...

OBJECTIVE: To investigate the effects of a specific aspect of the acquisition procedure, the averaging technique, on the evaluation of click-evoked otoacoustic emissions (CEOAEs) in newborns. DESIGN: CEOAEs were recorded by an Otodynamic ILO88 system from 89 full-term newborns at the third day after delivery. For each ear and in ...

The auditory function of four wild-caught echidnas was measured using distortion product otoacoustic emissions (DPOAEs) and auditory brainstem responses (ABRs). Emission audiograms were constructed by finding the stimulus levels required to produce a criterion emission amplitude at a given stimulus frequency. For an emission amplitude of -10 dB SPL, the ...

The amplitude versus frequency relations of distortion product otoacoustic emissions (DPOAEs) were studied in the guinea pig, using both the f(1)- and the f(2)-sweep paradigms to vary the primary frequency separation. The amplitude of the DPOAEs 2f(1)-f(2), 3f(1)-2f(2), 4f(1)-3f(2), and 2f(2)-f(1), plotted as a function of DP frequency, exhibited a ...

Guinea pigs were exposed to a pure tone at 6 kHz and 80 dB SPL for 30 minutes in order to induce mild reversible auditory fatigue over the 4 hours following exposure. Cochlear monitoring aimed to compare the shifts in round-window compound action potentials (CAP) thresholds to those of 2f1-f2 ...

To determine the effects of long-term, low-dose difluoromethylornithine (DFMO) on audiometric thresholds and distortion product otoacoustic emission (DPOAE) levels in humans. A prospective, randomized, placebo-controlled phase 2 clinical trial of DFMO in participants with a prior adenomatous colonic polyp. Academic tertiary care referral center. One hundred twenty-three volunteer subjects with ...