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Results for “Auditory Fatigue”

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At least 19 recordsLinked to original sources
PubMed1988

[Evaluation of the effect of auditory fatigue on the human ear by auditory brain stem responses (ABR). I. Effect of auditory fatigue on temporary threshold shifts of ABR].

The effects of auditory fatigue on auditory brainstem responses (ABR) were investigated in 23 normal-hearing subjects. ABR was recorded before and after exposure to fatiguing noise. Behaviourally, the auditory fatigue was tested using a temporary threshold shifts (TTS) paradigm. The latency of waves I, III, V and interwave intervals I-III, III-V, I-V were analysed as functions of stimulus intensity. In post-exposure recordings a threshold elevation, significant increase of all waves latency, increase of interwave-interval III-V at 40,50,60 dB nHL and unaltered intervals I-III, I-V were observed.

Adult↗
PubMed1988

[Evaluation of the effect of auditory fatigue on the human ear based on the measurement of brain stem auditory potentials (ABR). II. Relation of temporary auditory threshold shift and changes in the latency of wave V].

The relationship between temporary threshold shift (TTS) and latency changes of auditory brainstem responses (ABR) induced by noise exposure was studied in 23 normal-hearing subjects. Shift in latency wave V at 40 dB nHL of stimulus intensity as a result of auditory fatigue showed no significant correlation with TTS at 4 kHz. The great intersubject variability of shifts in latency wave V as a result of auditory fatigue suggests that this shift may be a useful measure of individual susceptibility to noise.

Acoustic Stimulation↗
PubMedDate not supplied

Developmental changes of susceptibility to auditory fatigue in young hamsters.

Susceptibility to auditory fatigue was studied in young hamsters by using an evoked-potential criterion of sound-induced threshold shift. Animals aged 15, 28, 40, 54 and 85 days were anesthetized and stimulated with a continuous tone (3 kHz, 110 dB SPL) for 10 min. Threshold shifts 1 min post-exposure were highest in animals aged 40 days, and lowest in animals aged 15 or 85 days. Threshold shifts recovered within 100 min in 15- and 85-day-old animals, but required considerably longer to recover in the other age-groups. The data suggest that young hamsters pass through a critical period of susceptibility to auditory fatigue. Comparison of this critical period with various indices of the development of hearing in the hamster suggests that the developmental events underlying the critical period do not occur in the middle ear.

Acoustic Stimulation↗
PubMed1988

Effects of intake and rejection tasks on auditory fatigue.

The effects of sensory intake and rejection tasks on auditory fatigue were examined in 14 male subjects. Auditory thresholds, psychophysical tuning curves and physiological measures of cardiovascular function were obtained before, during, and following a 7 min 110 dB SPL white noise exposure. Acceleration of heart rate was observed under the sensory rejection (mental arithmetic) condition, and poorer post-exposure auditory thresholds and larger Q10 tip values (measured during late post-exposure intervals) were seen when the task required counting of interruptions in the noise. However, Q10 tip values obtained 1 to 2 min post-exposure, when cochlear effects are maximal, failed to confirm a significant difference as a function of task.

Adult↗
PubMed1975

Auditory fatigue: retrocochlear components.

Changes in auditory sensitivity were measured at the VII nerve, cochlear nucleus, and inferior colliculus after a fatiguing sound exposure. Losses in sensitivity progressively increased from peripheral to central auditory sites. The results suggest that there is a retrocochlear component to auditory fatigue when it is induced by low-level sounds of short duration.

Acoustic Stimulation↗
PubMed1979

The effect of the stapedius reflex on attenuation and poststimulatory auditory fatigue at different frequencies.

The effect of the stapedius reflex on attenuation was measured in patients with unilateral facial palsy (Bell's palsy) and stapedius muscle paralysis. Poststimulatory auditory fatigue was determined in the same patients and in a group of normal test subjects with a normal bilateral stapedius muscle function. The attenuation for a 0.5 kHz tone was found to begin at the reflex threshold, to increase about 7 dB per a 10 dB increase in the stimulus tone and to reach a maximum in the vicinity of 20 dB. When a 2.0 kHz tone was used, no attenuation of note appeared until the sound had risen to about 10 dB above reflex threshold. The attenuation reached a maximum at a little less than 10 dB. A properly functioning stapedius muscle significantly reduced poststimulatory auditory fatigue at 0.75 kHz while at 3.0 kHz, it could do so only if it was stimulated into action by low-frequency noise.

Acoustic Impedance Tests↗
PubMedDate not supplied

Central auditory fatigue.

The results of this study, based on evoked responses and single-neuronal responses, reveal that there is a central involvement in auditory fatigue. In these experiments, cochlear potentials (microphonic and whole-nerve action potential) and inferior colliculus electrical responses were simultaneously obtained before and after excessive sound exposure. In general, sound exposure produced a greater reduction of the collicular evoked responses than of the cochlear microphonics and action potentials. Recordings from single neurons support the evoked-response findings.

Animals↗
PubMedDate not supplied

Comments on the relations between auditory fatigue and iris pigmentation.

It has been reported that subjects with highly pigmented irises (brown) experience significantly less temporary threshold shift (TTS) than subjects with less pigmented irises (blue), and that those with green-gray pigmentation display intermediate amounts of TTS. TOTA and BOCCI noted the high correlation between the melanin content in the stria vascularis and that found in the pigmentation of the iris; they attributed their TTS differences across eye colour to the protective effects of melanin. TTS data are reported in this paper as a function of eye colour for exposure stimulus parameters almost identical to those used by TOTA and BOCCI (1 000 HZ at 110 dB SPL for 3 min). The present results do not support the hypothesis that individuals with highly pigmented irises (brown-eyed) are more resistant to auditory fatigue than those with less pigmentation of the iris (blue-eyed). Median TTS at 20 sec post-exposure among brown, green-gray, and blue iris categories did not differ by more than 1.8 dB, and the median TTS at 2 min post-exposure among those iris categories did not differ by more than 0.2 dB.

Adult↗
PubMed1987

[Auditory adaptation and auditory fatigue].

Twenty subjects without otological disease were examined for auditory thresholds by Békésy audiometry and by the Feldmann Test (Adaptogramm), before and after noise exposure to one ear of 90 db SPL at 3 kHz for 15 minutes. The exposed ear was also tested for hearing fatigue (TTS). There was no significant correlation between Békésy audiometry and Feldmann test curves or between these adaptation tests and the hearing fatigue test (TTS) after noise exposure. Our results suggest that these methods of measuring adaptation do not correspond, and that adaptation measurements, prior to noise exposure, have no predictive value for hearing fatigue test results following noise exposure. After noise exposure changes were found in the non-exposed ear which were manifested as variability of the Békésy audiometry curves and flattened Feldmann curves. We thought that these results might indicate a central adaptation following noise exposure. There was interference of this so called "central adaptation" with peripheral fatigue in the exposed ear.

Audiometry, Pure-Tone↗
PubMed1978

Neural correlates of auditory fatigue: frequency-dependent changes in activity of single cochlear nerve fibers.

1. These experiments were designed to test whether intense pure tones produced greater depression of cochlear nerve fibers tuned to the exposure frequency or of those tuned to frequencies above the exposure frequency. Spike discharges of single fibers were studied in anesthetized cats before, during, and after exposures lasting 1 min. Exposure frequency was varied relative to each fiber's characteristic frequency (CF), and was either at the CF or 1/2 octave above (+1/2 oct) or 1/2 octave below (-1/2 oct) the CF. Exposure levels were 85 or 90 dB SPL. Effects of the various exposures on driven discharge rates were evaluated using standard test stimuli at each fiber's CF. In addition, nonevoked discharges were measured during the brief quiet intervals between test stimuli ("interstimulus activity") as well as during extended quiet periods ("resting activity"). Major results were as follows: 2. All the exposures resulted in depression of the driven discharge rates; however, these effects were strongly dependent on the exposure frequency. The depression was greatest and endured the longest following -1/2 oct exposures at 90 dB. The CF exposures at 85 and 90 dB were much less depressant, as were exposures at -1/2 oct at 85 dB; these three exposures resulted in very similar recovery functions. The +1/2 oct exposures produced little or no depression, whether at 85 or 90 dB. 3. Interstimulus activity was depressed immediately following all exposures, but recovered to normal quickly than did driven discharge rates. Following exposures at -1/2 oct at 90 dB, recovery was non-monotonic in that an extended period of supernormality preceded the return to normal rates. During this period of elevated activity, the interstimulus activity approached but never exceeded the resting rate of the same fiber. 4. Resting activity recovered even more rapidly than interstimulus activity, being completely normal by 1 min following all exposures. 5. These results constitute the first demonstration that the CF is not necessarily the most depressant exposure frequency for a given cochlear nerve fiber. Further, the results imply that the half-octave (or greater) shifts of the point of maximum hearing loss, so characteristic of auditory fatigue, may be accounted for by frequency-dependent alterations in the responsiveness of cochlear nerve fibers.

Acoustic Stimulation↗
PubMed1979

[Auditory fatigue in individuals having sustained an acoustic trauma (author's transl)].

A comparison was made between losses of auditory sensitivity after a fatiguing sound exposure of the ear in two groups of subjects: audiometrically normal subjects and subjects with early acoustic trauma. Subjects with cochlear impairment sustained an auditory loss apparently less than that of normal subjects when this loss is measured at threshold level. However, at supraliminal levels the loss of sensitivity, as measured here, would seem to be equal in both groups of subjects. In fact, the dynamics of sonic variations, already reduced by the cochlear impairment, is even further decreased by the effects of fatigue.

Audiometry↗
PubMed1988

Frequency selectivity in loudness adaptation and auditory fatigue.

An intermittent monaural tone may induce a decline in the loudness of a continuous tone presented to the same ear [Canévet et al., Br. J. Audiol. 17, 49-57 (1983)]. Two experiments studied the frequency selectivity of loudness adaptation induced in this manner. The method of successive magnitude estimations was used to measure the loudness of a monaural 84-s test tone before and after a single presentation of a 24-s inducer tone in the same ear. The first experiment shows that, for an inducing tone (500, 1000, or 3000 Hz) approximately 15 dB more intense than a test tone set to one of 21 different frequencies, adaptation is greatest when the two tones have the same frequency; with increasing difference between the test-tone and inducer frequencies, adaptation progressively declines. The second experiment measured frequency selectivity in the loudness reduction caused by a 1000-Hz inducer as a function of its level. As inducer level went from 75 to 95 dB (with test tone constant at 60 phons), selectivity passes progressively from the type seen in short-term or low-level fatigue (maximal for the 1000-Hz test tone) to a type seen in long-term or high-level fatigue (maximal for the 1000-Hz test tone) to a type seen in long-term or high-level fatigue (maximal at frequencies higher than that of the inducer or fatiguing tone). A common cochlear origin and a continuity between the mechanisms of ipsilaterally induced adaptation and high-level fatigue are suggested by the data.

Adaptation, Physiological↗
PubMedDate not supplied

Neurochemical basis of auditory fatigue: a new hypothesis.

Neuroactive polypeptides such as substance P and enkephalin have recently been demonstrated in the neuronal elements of the inner ear. It has been suggested that the same neuropeptides have a transmitter role in various sensory systems. Transmitter roles for the neuropeptides in the cochlear processes could provide new explanations for many physiological phenomena of hearing. The neuropeptides are particularly well suited to explain such a noise-induced auditory overloading condition as temporary threshold shift.

Animals↗
PubMed1975

The effect of the parasympathetic autonomic nervous system on auditory fatigue.

Volunteers with normal hearing were tested for vegetative balance with the aid of vegetative reflexes and with the aid of the atropine test. The effect of white noise stimulated on hearing thresholds was then investigated together with their recovery. The vegetative system was affected experimentally by intravenous administration of atropine, and the beginning and recession of hearing fatigue was observed. Atropine caused a small change only. In a similarly arranged experiment, 1% pilocarpin administered subcutaneously in a dose of 1.4 minus 1.6 ml, resulted in increased hearing fatigue and retarded recovery at higher frequencies. The effect of pilocarpin is explained by the fact that it supports the inhibitory processes checked by the parasympathetic nervous system on the periphery.

Acetylcholine↗