PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Auditory Threshold”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 73 records · Page 4Linked to original sources
PubMed1991

A timesaving BERA technique for frequency-specific assessment of the auditory threshold through tone-pulse series stimulation (TOPSTIM) with simultaneous gliding high-pass noise masking (GHINOMA).

A new stimulation paradigm is described for eliciting frequency-specific auditory brainstem responses (ABR) by stimulation with a series of seven Gaussian-shaped tone pulses with carrier frequencies descending, in half-octave steps, from 4,000 to 500 Hz, and an interstimulus interval between consecutive pulses of 18 ms. The pause between two consecutive series is 54 ms so that the interval between two tone pulses of the same frequency is 162 ms (stimulus repetition rate approximately 6/s). Simultaneously a high-pass noise masker is presented whose lower cut-off frequency is continuously diminished in such a way that, when a tone pulse is presented, the cut-off frequency of the masker is exactly one octave above the carrier frequency of the pulse. Forward masking effects of preceding tone pulses as well as forward and simultaneous masking effects of the high-pass noise suppress activity originating from those regions of the cochlea which are located basalwards to the region to be stimulated by the respective pulse, thus enhancing the frequency specificity, especially for low-frequency stimuli of higher intensity. The new stimulation paradigm was tested in 12 normal hearing subjects and turned out to be suitable to elicit frequency-specific ABR with frequencies as low as 500 Hz and intensities as low as 10 dB nHL. The main advantage of the described technique is that the time required for a complete assessment of the auditory threshold at seven test frequencies (covering the relevant speech frequency range) is substantially shorter as compared to conventional techniques so that it can routinely be employed in pedaudiology, where infants usually have to be investigated in sedation.

Acoustic Stimulation↗
PubMedDate not supplied

Response behavior around auditory threshold.

Normal adults, hearing-impaired preschool children, and normal-hearing mentally retarded children were assessed across repeated measures for auditory thresholds at 250 and 1000 Hz. Each subject's total performance across repeated measures was plotted by group by frequency relative to the last point of 100% correct response and interpolated thresholds. The results indicate that the steepness of the percentage of correct response performance curves and the variability of response performance above and below interpolated threshold were related to differences between the adult and child groups (mental age) and not between types of hearing populations (hearing sensitivity). The relationship between these results and experience with the signal is speculated.

Adolescent↗
PubMed1985

Extra-high-frequency auditory thresholds: fine structure, reliability, temporal integration and relation to ear canal resonance.

Three trained subjects were repeatedly tested for detection of auditory thresholds at 27 frequencies, from 2 to 18 kHz. A double-blind procedure was used with the method of adjustment, and the quasi-free-field delivery system of Osterhammel et al. [Scand. Audiol. 6:91-95, 1977] was used to monaurally stimulate the ear. A very reliable series of high- and low-threshold changes, termed the fine structure of the extra-high-frequency audiogram, was observed from 8 to 16 kHz. All 6 ears had a major low-threshold region at or near 13.5 kHz, and up to 3 other replicable sensitive frequencies along this one octave range. Thresholds were invariant over 3 conditions of stimulus presentation (constant tone; 500 ms duration, 25 ms rise and decay, 1 s interstimulus interval; and 100 ms duration, 1.5 ms rise and decay, 200 ms interstimulus interval). As the duration of the tone was decreased from 100 to 5 ms, temporal integration (an average of approximately 2.5 dB threshold increase as the duration was halved) was noted. Although temporal integration was slightly less at higher frequencies, the shape of the audiograms remained essentially unchanged as the stimulus duration was decreased to 5 ms. There was no consistent relationship between the maximally sensitive high frequencies and the amount of temporal integration. But there was a general association between the maximally sensitive high frequencies and the resonant frequency characteristics of that particular ear.

Adult↗
PubMed1988

The reliability of auditory thresholds in the 8- to 20-kHz range using a prototype audiometer.

This study was designed to evaluate both intra- and intertester reliability of auditory thresholds in the 8- to 20-kHz range using a recently developed high-frequency audiometer [Stevens et al., J. Acoust. Soc. Am. 81, 470-484 (1987)]. With this device, signals from a high-frequency transducer are introduced into the ear canal via a plastic tube. A calibration function is calculated for each ear and used to estimate the sound-pressure level (SPL) at the tympanic membrane. Twenty normal-hearing listeners were tested four times, twice by each of two examiners. In the higher frequencies, accurate calibration functions could not be obtained for many subjects; in these cases, values extrapolated from lower frequencies were used to estimate SPL. Findings reveal that the standard error of measurement for both intra- and intertester measures increases as a function of frequency. Intertester variability was only slightly higher than intratester variability. In most cases, variability of threshold estimates in dB SPL was higher than that observed for the uncorrected attenuator settings. Exclusion of extrapolated values improved reliability substantially.

Adult↗
PubMed1996

Salicylate-induced changes in auditory thresholds of adolescent and adult rats.

Shifts in auditory intensity thresholds after salicylate administration were examined in postweanling and adult pigmented rats at frequencies ranging from 1 to 35 kHz. A total of 132 subjects from both age levels were tested under two-way active avoidance or one-way active avoidance paradigms. Estimated thresholds were inferred from behavioral responses to presentations of descending and ascending series of intensities for each test frequency value. Reliable threshold estimates were found under both avoidance conditioning methods, and compared to controls, subjects at both age levels showed threshold shifts at selective higher frequency values after salicylate injection, and the extent of shifts was related to salicylate dose level.

Acoustic Stimulation↗
PubMed1983

Effects of brotizolam, flurazepam and placebo upon nocturnal auditory arousal thresholds.

Auditory awakening thresholds (AAT) and the back-to-sleep latency (BSL) after nocturnal awakenings from Stage 2 sleep were studied in normal male subjects after placebo, brotizolam (0.25, 0.375 and 0.50 mg) and flurazepam (30 mg). AAT (dB) was measured in five trials spaced across the night in a 'double awakening' procedure with the second awakening in each trial made from Stage 2 sleep. Each drug condition was associated with elevated mean AAT across the five trials in comparison with placebo. In a trial-by-trial analysis only 0.50 mg brotizolam and 30 mg flurazepam were consistently higher in the first three trials compared with placebo. All active drug conditions decreased the mean BSL across all trials in comparison with placebo, but only 30 mg flurazepam and 0.50 mg brotizolam consistently shortened BSL in the first three trials. Brotizolam (0.50 mg) and 30 mg flurazepam are similar in their effects. The subjective improvement reported in insomniac subjects following hypnotic administration may be related to elevation in arousal thresholds and a quick return to sleep after nocturnal sleep disruption.

Acoustic Stimulation↗
PubMed1985

Colony differences in auditory thresholds in the canary (Serinus canarius).

Adult canaries (Serinus canarius) from a closebred colony of the Belgian "Waterslager" strain were trained with operant techniques to respond to pure tones. A psychophysical tracking procedure was used to measure absolute auditory thresholds in quiet and in noise. Absolute thresholds in the middle- to high-frequency region of the audiogram were between 30 and 40 dB higher (4-5 standard deviations) than those typically reported for other song birds including canaries of other strains and Waterslagers tested some years ago from another colony. Thus the Millbrook colony of domestic canary--an oscine songbird which learns its vocalizations by reference to auditory information--shows unusually high absolute thresholds for pure tones.

Animals↗
PubMed2006

Asymmetry of masking in the European starling: behavioural auditory thresholds.

Psychophysical studies of simultaneous masking with human observers exhibit an asymmetry in the amount of masking that depends on the relative bandwidths of signals and maskers. For noise bands up to the bandwidth of one auditory filter, masked auditory thresholds are considerably lower when the bandwidth of the signal exceeds that of the masker compared to the reversed condition. We investigate asymmetry of masking in an animal model, that will allow to study the mechanisms associated with the asymmetry of masking effect. European starlings (Sturnus vulgaris) were trained in a Go/NoGo paradigm to report the detection of a 500 ms noise signal centred in a 700 ms noise masker. Signals and maskers with centre frequencies of 2 kHz had bandwidths of 4 Hz or 256 Hz. Thresholds for detecting the 256 Hz wide-band signal in a 4 Hz narrow-band masker were considerably lower compared to detecting the 4 Hz narrow-band signal in a 256 Hz wide masker and compared to all other conditions. The asymmetry of masking in starlings was on average 15 and 17 dB for 40 and 70 dB SPL overall masker level, respectively. Our animal model thus proved perceptual abilities similar to human subjects. The results are discussed with respect to the importance of both intensity and temporal cues for signal detection.

Animals↗
PubMed1976

Auditory thresholds in the guinea pig: a preliminary report of a behavioral technique employing a food reward.

Guinea pigs have been trained to press a lever for a food reward. Then the behavior was used to obtain the auditory thresholds for six guinea pigs. The thresholds obtained in the present study agree with those previously obtained by Heffner, et al. The most important aspect of the training process was the habituation of the guinea pigs. Once the guinea pig was accustomed to the food and training cage, he could be trained in a manner similar to that used to train many other species.

Animals↗
PubMed1994

Human fetal auditory threshold improvement during maternal oxygen respiration.

It has been suggested that the near full-term fetus in-utero has a sensori-neural hearing loss compared to the neonate due to the relative hypoxia resulting from placental oxygenation compared to pulmonary oxygenation. This hypothesis was tested by estimating the threshold of the fetus to vibrio-acoustic stimulation applied to the maternal abdomen while the mother was breathing room air and again when breathing oxygen. Fetal response was assessed by maternal perception of fetal movement and by objective demonstration of movement by ultrasound. It has been shown that the fetal responses are to the acoustic component of the stimulus, that the acoustic stimulus is not overly attenuated or masked, and that maternal oxygen inhalation enhances fetal oxygenation. The results showed that the threshold was lower and/or the response was stronger when the mother was breathing oxygen compared to when she was breathing room air. Thus it is confirmed that in-utero the fetus has an hypoxia-induced sensori-neural hearing loss. At birth, with the shift to more efficient pulmonary oxygenation, there is an improvement in auditory threshold.

Acoustic Stimulation↗
PubMed2003

Acute effects of alcohol on auditory thresholds and distortion product otoacoustic emissions in humans.

OBJECTIVE: To investigate the acute effects of alcohol consumption on pure-tone thresholds (PTs) and distortion product otoacoustic emissions (DPOAEs) in humans MATERIAL AND METHODS: Eight healthy adults were asked to drink alcohol to the clinical intoxication level. PTs and DPOAEs were determined serially before and after alcohol ingestion. RESULTS: Alcohol had no effect on PTs DPOAE amplitudes above 5500 Hz dropped 30 min and 1 h after alcohol ingestion, returning to the pre-test level 2 h after ingestion. CONCLUSION: In humans, acute alcohol consumption to the intoxication level may cause a temporary reduction in DPOAE amplitudes at high frequencies without affecting auditory thresholds.

Adult↗
PubMed1991

The effects of external- and middle-ear filtering on auditory threshold and noise-induced hearing loss.

A model of external- and middle-ear function is described that uses existing data to quantify the flow of sound power from the environment to the cochlea of humans, cats, and chinchillas. This model estimates the sound power produced at the entrance of the cochlea by an environmental sound stimulus, and can be used to predict the shape of the auditory threshold function and the relative potency of various traumatic acoustic stimuli. The shapes of the predicted and measured threshold functions in the three species are similar in best frequency, bandwidth, and low-frequency slope, and the model accurately predicts the hypersensitivity of the middle-frequency regions of the cochlea to acoustic trauma. The model assumes that the mechanics of the middle-ear system are linear even at high stimulus levels and does not include the effects of either middle-ear or cochlear efferent loops. The effects of these simplifications on the model are discussed as are the implications of the model results for hearing protection and damage risk criteria.

Animals↗
PubMed1989

[Objective determination of auditory threshold in the child].

In children who are difficult to test with dubious behavioural-audiometric results, brainstem electric response audiometry (BERA) is today the method of choice for accurate determination of hearing threshold. Oral sedation with the shortacting neuroleptic chloroprothixene allows BERA to be performed on an outpatient basis. Thirty-six girls and 41 boys aged between 11 weeks and 12 years (median age 40 months) with inconsistent behavioural-audiometric findings were examined. Frequency-following responses were searched for in flat fast response curves. BERA proved to be a very sensitive method compared with behavioural audiometry and was reliable even for children who are difficult to evaluate clinically, and for asymmetrical auditory thresholds. In conjunction with the standard pedaudiological test battery, BERA improves diagnostic accuracy and causes little disturbance as an outpatient procedure.

Audiometry, Evoked Response↗