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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)
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)
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)
We analyzed the cortical responses to standard stimuli presented in an auditory oddball paradigm from two groups of young and elderly participants in unattended and attended conditions. A sustained negativity (N2) followed N1 and P2 in the responses of the young participants. This negativity was reduced or absent in the elderly. With attention, the early(More)
Otoacoustic emissions of distortion products (DPOAE's) were recorded in normal and hearing-impaired human ears using relatively straightforward methods. Two pure-tone stimuli at fixed frequency levels of 73 dB HL for f1 and of 67 dB HL for f2 were used. The frequencies of the two primaries were chosen so that their geometric mean represented standard(More)
Otoacoustic emissions were evoked in the same ears with single tone bursts at 1, 2 and 3 kHz and with a complex stimulus consisting of a digital addition of the three tone bursts. Stimuli were presented at 75, 59 and 37 dB SPL to 28 ears of human subjects with normal hearing. The purpose was to determine if comparisons of responses to the complex stimulus(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)
Temporal auditory processing deficits are thought to play an important role in some pathologies of speech understanding difficulties. The purposes of the present study were to determine whether short silent gaps within a pure tone can be used to elicit mismatch negativity (MMN) as an objective measure of temporal resolution, and to investigate the relation(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)
OBJECTIVE To evaluate the benefits of bilateral electrical stimulation for hearing-impaired adult subjects using the Nucleus 24 cochlear implant in a multicenter study, and to compare and quantify performance on speech perception measures in quiet and in noise and localization ability for unilateral and bilateral cochlear implant use. DESIGN : Repeated(More)