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PubMed1982

Auditory thresholds in children for narrow-band noise and warble tones in sound field.

Auditory thresholds for frequency-modulated (warble) tones and narrow bands of noise in a sound field were obtained for children between the ages of eight and 48 months. Differences between the two types of stimuli centered at either 500 Hz or 4,000 Hz and among three age groups were not statistically significant (P greater than 0.01). Auditory thresholds for these frequency-selective stimuli did coincide closely with the speech awareness and spondee threshold measurements obtained in the present study, and with thresholds for complex noise obtained in previous reports. Sound field warble tone thresholds differed, however, from published data in adults and unpublished data in children. Explanations for discrepancies between data in present study and previous studies are suggested, and a cautious recommendation for the use of frequency-selective stimuli in the assessment of auditory thresholds in children is emphasized.

Acoustic Stimulation↗
PubMed2003

Effects of contralateral noise on the measurement of auditory threshold.

It is well known that sound presented in the contralateral ear can elicit the activity of the olivocochlear (OC) efferent. In the present study, the effects of the addition of contralateral noise on the psychophysical measurements of auditory thresholds were investigated in human subjects with normal hearing. The results obtained in the present study indicate that the addition of contralateral noise at a level of only 20 or 30 dB sound pressure level (SPL) may cause a significant elevation of the auditory threshold in the mid-frequency area (usually 2-3 dB). When the level of contralateral noise was elevated, the elevation of the auditory threshold tended to be larger and the affected frequency area became wider. Although other factors that elevate the auditory thresholds, such as cross-talk effects and the acoustic reflex of the middle ear muscles, may be involved in the above-mentioned paradigm, especially when higher levels of contralateral noise are used, it is important to know the degree of OC-mediated threshold elevation in usual audiometric measurement.

Audiometry, Pure-Tone↗
PubMed2000

The auditory threshold in a school-age population is related to iodine intake and thyroid function.

The aim of this study was to determine the relationship between auditory capacity and urinary iodine, taking into account thyroid volume and function, in a population of school-age children. Audiometry was carried out in 150 children (ages 6-14 years), together with measurements of thyroid volume, thyrotropin (TSH), free T3, free T4, thyroglobulin, antiperoxidase and anti-TSH receptor antibodies, as well as iodine in a casual urine sample. Children with a TSH >5 microU/mL were excluded from the study. In the children with palpable goiter, there was an inverse relation between the auditory threshold at all frequencies and ioduria. Children with thyroglobulin values >10 ng/mL had a higher auditory threshold at all frequencies. In the children with palpable goiter and ioduria <100 microg/L, the levels of thyroglobulin and ioduria and the age accounted for 75% of the decibel (dB) variance at 2000 (Hertz), with similar results at other frequencies. The children with a thyroid sized at the >95th percentile had an odds ratio of 3.86 (95% confidence interval: 2.59-5.10) of having a threshold >20 dB. The results warn that iodine prophylaxis is needed to prevent not only goiter but also other iodine-deficiency disorders, such as involvement of the auditory threshold in school-age children.

Adolescent↗
PubMed1977

Sex of listener and hormonal correlates of auditory thresholds.

The present study investigates changes in auditory threshold during 4-6 week intervals for men, women on birth control pills, and normal cycling women not on birth control pills. Thresholds were determined at 250, 500, 1,000, 2,000, 4,000, 6,000, 8,000 Hz. Normal cycling females had significantly lower thresholds during first half of the menstrual cycle than during the second half. Females on birth control pills showed significantly and consistently lower thresholds than other listeners at several frequencies. Explanations for the phenomena are proposed.

Adolescent↗
PubMed1983

Test-retest reliability of auditory threshold and temporary threshold shift.

Test-retest reliability of auditory threshold and temporary threshold shift (TTS) at 4 kHz and 8 kHz was examined. Twenty normally hearing subjects were exposed to a 3-min 110 dBSPL white noise on three occasions. Results indicated reduced reliability of both threshold and TTS scores over time, rendering 1-week TTS correlations non-significant.

Audiometry, Pure-Tone↗
PubMed1981

Postnatal development of absolute auditory thresholds in kittens.

Postnatal development of absolute auditory thresholds in the kitten was behaviorally measured from birth up to 1 mo of age. Unconditioned reactions to pure tones were observed for kittens up to Day 12, and conditioned responses were used for animals from Day 10 onward. At 1 day after birth, the first noticeable responses were obtained in 4 of 11 kittens at frequencies of .5-2 kHZ. At 2 days of age, 12 of 16 kittens responded. Thresholds remained high (above 100 dB SPL) up to the sixth day, but the range of behaviorally effective frequencies extended from .2 to 6 kHZ. All conditioned response thresholds at Day 10 and most at Day 12 were significantly lower than those measured by unconditioned reactions. From 10 days onward, all threshold curves showed a characteristic sensitivity optimum at 4 kHZ. For frequencies below 1 kHZ, maximum sensitivity was reached at Day 15; for frequencies up to 20 kHZ, at Day 20; and for even higher frequencies, at Day 30. At 1 mo of age, the frequency range is adultlike. The present behavioral results on developing acoustic function in the kitten closely followed structural maturation of the acoustic pathway and demonstrated limitations of the ability for acoustical communication during the first week of life.

Aging↗
PubMed1990

[Agreement between auditory threshold calculated from cortical evoked response audiometry and tone audiometry in occupational hearing loss].

In a group of 126 men the authors evaluated the auditory threshold from cortical ERA findings and comparison with their threshold sound audiometry. The mean age of the patients means = 52.5 years (min. = 25 years, max. = 69 years, s = 8.95). Noise exposure means = 16.5 years (min. = 4 years, max. = 30 years, s = 4.5). In 79.3% the men worked as miners in uranium mines, other mining occupations were represented only by small numbers. The arithmetic mean of the total percentage hearing loss (calculated according to Fowler) means = 49.7% (min. = 17%, max. = 100%, s = 15). The cumulative frequency of differences between the auditory threshold of the sound audiogram and cortical ERA: (table; see text) The cumulative frequency of differences in the total percentage hearing loss between sound audiograms and cortical ERA: differences up to +/- 5% hearing loss were recorded in 24.3% of the group, differences up to +/- 10% in 43.9%, differences up to +/- 15% in 58.9%, differences up to +/- 20% in 70.1%. In the group of 126 examined subjects we detected 12 aggravating subjects (9.5%), their mean age being by 6.7 years lower than the mean of the whole group, the mean exposure to noise is by 3.2 years shorter. The differences between the auditory threshold reported by the aggravating men and the cortical ERA are highest in verbal frequencies, on average they are per fr of 2 kHz 27.3 dB, 1 kHz 24.3 dB, 0.5 kHz 20.1 dB, 4 kHz, 10.0 dB. The differences between the total percentage auditory loss calculated from sound audiograms and cortical ERA reaches on average 41.5%.

Aged↗
PubMed1995

[Diagnosis of auditory threshold with frequency-specific recording of auditory evoked potentials: personal results and methodological aspects].

Results and Overview of Methods: Auditory brain stem responses are widely used in objective assessment of hearing function in both children and adults. Because of the lack of frequency specificity, several attempts were made to optimize responses using tone stimuli. Tone stimuli are characterized by intensity, frequency, and duration. Hence, there are important influences on the waveforms with respect to rise, plateau, and fall time. In addition, noise masking techniques are used to suppress both spectral sidebands of the stimulus and cochlear response not corresponding to the test frequency. In this paper, results on tone burst stimulation in notched noise masking are presented. Using this technique, reproducible waveforms (Jewett I to V resembling peaks) including a middle latency component could be obtained. Various stimulus characteristics (clicks, tone pips, tone bursts, Gaussian shaped stimuli), masking techniques (high-pass noise, notched noise), spectral characteristics, and time saving strategies are critically discussed.

Acoustic Stimulation↗
PubMed1992

[Changes in the auditory threshold of workers exposed to the combined action of noise and local vibrations].

Study is performed on the effect of noise and local vibrations during a combined effect and independently on the auditory threshold for 4 kHz. The audiometric data of 1242 workers from the textile industry, coal- and ore production are analysed. On the basis of precise assessment of the noise level and occupational exposure to noise and local vibrations are formed 4 groups: exposed to independent noise effect with intensity 90 and 100 db (spinners and dressmakers); exposed to combined effect of noise (91 and 103 db) and local vibrations, surpassing the maximum admissible norms respectively 2.5 and 3.5 times (miners of coal- and ore production). In view of the occupational exposure and standardization concerning age and length of service the audiograms of 248 persons are examined. The following is established: different rate of increase of the auditory threshold for 4 kHz depending on the intensity of the factors noise and local vibrations in conditions of independent and combined effect: positive correlation with the length of service in the changes of the auditory sensoriness; dynamics in the increase of the auditory threshold for 4 KHz.

Adult↗
PubMed1979

Effects of d-amphetamine and methylphenidate upon auditory threshold in the squirrel monkey.

The effects of d-amphetamine sulfate and methylphenidate hydrochloride on auditory thresholds in ten squirrel monkeys were examined using a 4.2 kHz stimulus in a free field. The results indicated that d-amphetamine raised auditory thresholds but methylphenidate did not alter the thresholds. The elevation of sensory thresholds by d-amphetamine was in agreement with previous studies suggesting that the drug acts as a behavioral depressant in diurnal animals.

Animals↗
PubMed1994

AUDITORY THRESHOLD CHANGE IN SINGING CICADAS

The hearing sensitivity in singing cicadas is reduced during sound production by a folding of the tympanal membranes. Using electrophysiological recording and nerve stimulation techniques, we have shown an effect of the folded tympanum on the auditory threshold of two species of cicadas, Tibicen linnei and Okanagana rimosa. Auditory thresholds of both species increased by about 20 dB when the tympana folded during singing. In T. linnei the increase in threshold affected the whole frequency range, from 1 to 16 kHz, in a similar way. Electrical stimulation of one or both auditory nerves resulted in a folding of both tympanal membranes in a way very similar to that seen in singing animals. We have demonstrated that a cicada male is able to adjust its auditory threshold within a range of about 20 dB by the tympanal folding mechanism.

Journal Article↗
PubMed1989

[The relation between the auditory threshold and the threshold of middle ear reflexes induced by ipsilateral stimulation in occupational deafness].

The author examined and evaluated middle ear reflexes obtained by ipsilateral stimulation in a group of 115 men, mean age 52.5 years (s = 9 years) who worked exposed to noise in uranium mines on average for 16.5 years (s = 4.6 years). Their total percentage auditory loss calculated according to Fowler is 49.7% (s = 15.1%). The arithmetic mean of differences of the auditory threshold and the threshold of middle ear reflexes in 214 ears examined at a frequency of 1000 Hz is 45.5 dB (s = 16.3 dB, min. 0 dB, max. 80 dB), in 208 ears at a frequency of 2000 Hz 30.4 dB (s = 13.5 dB, min. 0 dB, max. 75 dB), in 196 ears at frequency 3000 Hz 23.2 dB (s = 12.6 dB, min. 0 dB, max. 85 dB). The relation--ship between the auditory threshold and middle ear reflexes obtained by ipsilateral stimulation corresponds to the following equations Y1000Hz = 105.86--9.73 square root chi i Y2000Hz = 119.21--11.61 square root chi i Y3000Hz = 108.62--10.59 square root chi i Individual forecasts of the auditory threshold for pure tones only from values of the threshold of middle ear reflexes in occupational deafness are of restricted value due to the great scatter of values.

Auditory Threshold↗
PubMedDate not supplied

Correlations between cochlear hair cell loss and shifts of masked and absolute behavioral auditory thresholds in the house mouse.

Masked and absolute behavioral auditory thresholds were measured in kanamycin-treated C3H mice with a significant damage or loss of outer hair cells (OHCs) near the cochlear base, and in 17--24-month-old NMRI mice with a significant loss of OHCs and inner hair cells (IHCs) in the basal region and of OHCs near the apex. A loss of IHCs is correlated with an increase in absolute thresholds. A moderate damage or loss of OHCs in a cochlear region had no effect on absolute thresholds but correlated with a decrease and other changes of characteristics of masked thresholds in the respective frequency regions. OH C-damage makes masking by continuous white broad-band noise less efficient. It is concluded that masking and critical bands depend on the function of OHCs, which must be assumed to influence intracochlearly the activity of IHCs in processing the information to the brain.

Animals↗
PubMed1986

Auditory thresholds during continuing sleep.

Five subjects were asked to respond to a 1000 Hz tone with a standard button push response during sleep. A method of limits procedure was used to track their auditory thresholds when awake and during various stages of sleep. Subjects adapted to the procedure and were able to make consistent responses while their EEG indicated stage 1 or stage 2 sleep. While the threshold level at which a response was made was directly related to EEG state, there was no significant correlation between the interval between responses and the threshold level. It was concluded that stable auditory thresholds could be obtained during stage 1 and stage 2 sleep after little laboratory adaptation and that this behavioral response could be a useful indicator of central processing ability during sleep.

Acoustic Stimulation↗
PubMed1996

Auditory threshold shift following meatal pressure change in ossicular disorders.

Auditory threshold shifts for air conduction following meatal pressure changes were examined in 30 normal ears and in 27 ears with ossicular abnormalities. Negative and positive changes in meatal pressure caused threshold elevation at frequencies lower than 1,000 Hz in all normal ears. In the ears with ossicular fixations, air pressures were less effective in attenuating hearing as compared with normal ears. Clearly different results were obtained in the patients with incudostapedial disconnection without stapes fixation. Thresholds were elevated by positive pressure, although marked threshold gains were measured by negative pressure at low frequency tones. Differences in threshold levels between the air pressures of +200 and -200 mm H2O were 26 to 40 dB at 250 Hz. This marked reverse effect in direction of the threshold shifts cannot be explained only by relative compliance changes in the tympanic membrane. Possible mechanisms underlying this phenomenon are discussed.

Adolescent↗