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At least 235 records · Page 13Linked to original sources
PubMed1999

The relationship between auditory threshold and evoked otoacoustic emissions.

The aim of this study was to compare transiently evoked otoacoustic emissions (TEOAE) and distortion product otoacoustic emissions (DPOAE) in normal hearing ears (n = 44) and ears with cochlear hearing loss (HL) to obtain defined data on qualitative and quantitative correlations. In addition, we wanted to determine the reliability with which a clinical examiner could predict a typical, idealized audiometric configuration from TEOAE measurements. In the hearing-impaired subjects (n = 149), a 50% reduction of OAE incidence was caused by a mean HL of 10.5 dB for TEOAE compared to 27 dB SPL for DPOAE. A 90% incidence reduction was found at a mean threshold elevation of 33 dB for TEOAE and 51 dB for DPOAE. Correlation between TEOAE amplitudes and HL was in general rather low (r = -0.1 to -0.5), while DPOAE amplitudes showed a slightly better correlation with HL (r = -0.3 to -0.6). In general, efforts to derive an audiogram from evoked OAE have been more promising for DPOAE than for TEOAE. However, our studies showed that approximately 40% of the ears with HL could be categorized correctly into one of five typical audiometric patterns from TEOAE measurements. Additionally, a cochlear HL in or near the medium frequency range was much more likely to cause a reduction in TEOAE than an isolated low- or high-frequency lesion. Accordingly, TEOAE were often preserved in ears with isolated HL in the high or low frequencies.

Acoustic Stimulation↗
PubMed1978

Temporal summation of constant and gliding tones at masked auditory threshold.

Masked thresholds for constant and gliding tones were determined by the method of adjustment for durations between 0.5 and 5000 ms in three overlapping frequency regions between 0.25 and 3.3 kHz. The masker was a continuous white noise at 70-dB SPL. Listening was monaural; subjects had normal hearing. Below 10 ms the thresholds for upward glides were lower and those for downward glides higher than the thresholds for constant tones. In the 10--300 ms duration range, which encompasses formant transitions of speech, the highest thresholds are for downward glides and the lowest ones for constant tones. These differences could result from different time courses of neural decay and inhibition for constant tones, upward and downward glides. The differences between upward and downward glides indicate that the phase spectra influence sound detectability. The thresholds for constant tones reach minimum around 1 s. The thresholds for glides continue to decrease at least up to 5 s. The "critical" duration for constant tone integration can result from the overriding of integration effects by adaptation effects, the latter ones being eliminated by changing frequency. The curves for constant-tone threshold between 10- and 1000-ms duration were fitted by a product of exponential and hyperbolic functions.

Auditory Threshold↗
PubMed1995

[Referential value of auditory threshold depending on age].

The value of "normal hearing" intended as the "base value of reference" to be used also for preventive as well as medical-legal purposes, is still subject of study and discussion. The Authors present the results relative to the definition of the hearing threshold in a vast "scrupulously screened" group of subjects between the ages of 15 and 65 (divided into 10 year bands), resident in industrial city areas and made up a homogeneous group of industrial workers with the same socioenvironmental characteristics. Distribution is calculated in hundreds of values relative to the average bilateral threshold for frequencies between 500 and 4000 Hz considering the 90th percentile the reference value.

Adolescent↗
PubMed1982

Auditory thresholds of a captive Eastern Pacific bottle-nosed dolphin, Tursiops spp.

The hearing threshold of a bottle-nosed dolphin from the Eastern Pacific was tested using behavioral response techniques. The animal responded to signals ranging from 2 to 135 kHz, but did not respond to higher frequency signals (136-160 kHz) despite repeated trials. The range of greatest sensitivity was between 25 and 70 kHz with peak sensitivities at 25 and 50 kHz. This measured hearing threshold is compared to frequency responses and sensitivities previously reported for other cetaceans.

Animals↗
PubMed1984

Ultrahigh-frequency auditory thresholds in young adults: reliable responses up to 24 kHz with a quasi-free-field technique.

A quasi-free-field technique was used to assess detection thresholds to pure tones, at frequencies ranging from 2 to 24 kHz. The sound delivery system of Osterhammel et al. [Scand. Audiol. 6:91-95, 1977] was modified in order to deliver constant stimuli at SPLs of at least 117 dB over the entire frequency range. A modified form of the method of adjustment maintained the subjects' interest, and a double-blind procedure minimized experimenter and subject bias. In the first experiment, 78 university subjects from Northern California (18-24 years old) were exposed to tones in 2-kHz increments. All but 12 of these persons could reliably detect the highest frequency, with females being slightly more sensitive. But from 10 to 20 kHz, there were no differences between the sexes. In a second group of 20 students, tested in 1-kHz increments from 8 to 16 kHz, the previously observed 10- to 14-kHz threshold plateau was revealed as a pronounced 13-kHz low-threshold region. The threshold at this frequency was approximately 14 dB lower than the 11-kHz threshold. These data were compared with those obtained in a similar fashion from other cultures.

Adolescent↗
PubMed2004

Auditory steady-state response evaluation of auditory thresholds in cochlear implant patients.

The aims of this work were to characterize the electrophysiologic response obtained by measurement of the auditory steady-state response (ASSR) in patients with a cochlear implant (MXM Digisonic) and to study the relationship between the subjective thresholds of the implantees and those estimated using electrical auditory steady-state response (ASSR)-based objective audiometry. Five subjects were examined with the use of four carrier frequencies--600, 1000, 2000 and 3500 Hz--modulated at frequencies between 70 and 85Hz, a particular frequency of modulation being represented at a specific electrode (for each carrier frequency) as a particular pulse-width modulation frequency. The protocol consisted of testing output and thresholds for different overall pulse durations for several stimulus (pulse) intensities, rendering multiple threshold measures (in duration) for each subject tested. The non-linearity of response growth, as a function of duration, provided the basis for teasing apart physiologic response and electrical artefact in the suprathreshold recorded responses. Thresholds estimated with use of the electrical ASSR demonstrated reasonably good agreement with the subjective thresholds. The results obtained thus demonstrated the efficacy of the approach and are encouraging for further advances in cochlear implant applications.

Acoustic Stimulation↗