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The effects of primary-tone separation on the amplitude of distortion-product emissions (DPEs) at the 2f1-f2 frequency were systematically examined in ten ears of five subjects. All individuals had normal hearing and middle-ear function based upon standard clinical measures. Acoustic-distortion products were elicited at 1, 2.5, and 4 kHz by equilevel(More)
Otoacoustic emissions measured in the external ear canal describe responses that the cochlea generates in the form of acoustic energy. For the convenience of discussing their principal features, emitted responses can be classified into several categories according to the type of stimulation used to evoke them. On this basis, four distinct but interrelated(More)
The 2f1-f2 distortion-product otoacoustic emission (DPOAE) is evoked by two primary tones of frequencies f1 < f2, and levels L1 and L2. Previous reports indicate that decreasing L2 below L1 = L2 can; (1) increase DPOAE amplitude in normal ears, and (2) increase the degree to which DPOAE amplitudes are reduced by cochlear trauma. Although both of these(More)
Otoacoustic emissions in both ears of a rhesus monkey exhibiting stable spontaneous emissions (SOEs) were monitored over a 1-year period. The amplitudes and frequencies of both SOEs and stimulus-frequency emissions (SFEs) were routinely recorded, while transiently evoked (EOE) and distortion-product emissions (DPEs), at the frequency 2f1-f2, were(More)
Otoacoustic emissions can be used to study cochlear function in an objective and noninvasive manner. These features of emitted responses have stimulated a great deal of investigation into the utility of evoked emissions as clinical tests of hearing. One practical and essential aspect of any clinical measure is the consistency of its result upon repeated(More)
Both cochleas of a rhesus monkey exhibiting stable spontaneous and stimulus-frequency emissions were evaluated histologically using surface-preparation methods to determine if certain features of these emissions could be related to structural properties of the organ of Corti (OC). The comprehensive assessment included preparation of routine cytocochleograms(More)
Previous work on acoustic distortion products (DPs) recorded from the ear canal has not established unequivocally whether emitted DPs principally reflect basilar-membrane nonlinearities at the frequency sites of the primary tones, f1 and f2, or if the DP-frequency place itself makes a significant contribution to the emitted response. Results from some(More)
In contrast to evoked otoacoustic emissions, acoustic distortion products (DPs) recorded from the ear canal are present at predictable frequencies with respect to their primary tones, f1 and f2. Such specificity may provide detailed frequency-place information concerning the functional state of limited regions of the organ of Corti following experimental(More)
Otoacoustic emissions permit, for the first time, an unbiased means of examining the preneural elements of the peripheral auditory pathway that make the initial contribution to the perception of acoustic stimuli. Distortion-product otoacoustic emissions (DPOAEs) represent one type of evoked emission that has significant potential for becoming an important(More)
Otoacoustic emissions have great promise for use in clinical tests of the functional status of outer hair cells, which represent cochlear structures that make a major contribution to the hearing process. A substantial literature is available concerning the evaluation of outer hair cell function by transiently evoked otoacoustic emissions. However,(More)