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At least 91 records · Page 5Linked to original sources
PubMed2002

[Stability of auditory thresholds during the first 5 weeks after stapedectomy].

To assess repeatability of audiological test performed every week during the first month post-stapedectomy, audiometry was performed to 21 patients with otosclerosis (mean age 37.8 years, S.D. 9.29), every week, during the 2 weeks prior to stapedectomy and during the first 5 weeks and at week 12 after stapedectomy. Repeatability of the audiological test was evaluated comparing the difference between the audiological evaluations performed before the surgery and the difference between each consecutive pair of audiological evaluations after the surgery, using Bland & Altman method and ANOVA, allowing for 5% of significance. Before the surgery, audiological thresholds, using head phones, were repeatable for low (125-500 Hz), mid (500-2000 Hz) and high (2000-8000 Hz) frequencies in 95% of the patients. After the surgery, repeatability of air conduction thresholds for the low frequency band was evident from the 2nd week, for the mid frequency band was evident from the 3rd week and for the high frequency band from the 4th week. The gain observed at week 5 after surgery was similar to the gain observed at week 12. In conclusion, in this study, stable air conduction auditory thresholds were obtained during the first month after stapedectomy.

Adult↗
PubMed1996

[Reaction times at auditory threshold: a comparison of normal hearing probands and patients with hearing damage].

BACKGROUND: The purpose of the study was to examine the latencies between tonal stimuli and response of normal ears at the threshold compared with ears with a frequency-specific threshold above 70 dB. PATIENTS AND METHODS: Reaction times to tonal stimuli of 122 adults with normal hearing and adults with hearing loss were compared at the threshold of hearing to reaction times beyond the threshold. The study group of tested patients was divided into four groups corresponding to the frequency-specific hearing loss on the basis of previous audiometric investigations. RESULTS: The results reveal that response latencies in ears with normal hearing asymptomatically approach the auditory threshold. In contrast, we failed to measure a significant prolongation of reaction times in presence of extensive hearing loss (above 70 dB) even at the minimum level of auditory perception. In the presence of extensive hearing loss (above 70 dB), we detected a significantly lower rise of threshold response latencies at normal audiometric frequencies than in normal ears. CONCLUSION: The reaction time results are evaluated, and the possible role of the outer hair cells are discussed.

Adult↗
PubMed1993

Behavioral measures of auditory thresholds in developing tree shrews (Tupaia belangeri).

The development of hearing in tree shrews (Tupaia belangeri) was tested through behavioral measures in the range of 0.3-60 kHz from the first postnatal thresholds detectable through to those of weanlings. The onset of hearing was defined using unconditioned startle responses, while, later on, pinna reflexes and head movements were used as behavioral indicators of sound perception. Startle responses could be evoked from day 16 after birth (DAB) onwards, indicating that the hearing system is capable of transferring airborne sound, although no reactions to tones were recorded at this age. The first unconditioned reactions to tones were found at DAB 18 in the range of 1-5 kHz (range of mother-infant call). Responses were restricted to the range of greatest sensitivity in adults (1-10 kHz). An increase in sensitivity was detected from DAB 18-38. The lowest tested frequency (0.3 kHz) reached adult levels earlier than higher frequencies. No further improvement of auditory thresholds could be observed from DAB 38 (end of nutritional weaning) to DAB 42. Results were related to recent findings on the development of acoustical behavior and of the peripheral and central auditory system of tree shrews and other mammals.

Acoustic Stimulation↗
PubMed1998

Broadband spectra of seismic survey air-gun emissions, with reference to dolphin auditory thresholds.

Acoustic emissions from a 2120 cubic in air-gun array were recorded through a towed hydrophone assembly during an oil industry 2-D seismic survey off the West Wales Coast of the British Isles. Recorded seismic pulses were sampled, calibrated, and analyzed post-survey to investigate power levels of the pulses in the band 200 Hz-22 kHz at 750-m, 1-km, 2.2-km, and 8-km range from source. At 750-m range from source, seismic pulse power at the 200-Hz end of the spectrum was 140 dB re: 1 microPa2/Hz, and at the 20-kHz end of the spectrum seismic pulse power was 90 dB re: 1 microPa2/Hz. Although the background noise levels of the seismic recordings were far in excess of ambient, due to the proximity of engine, propeller, and flow sources of the ship towing the hydrophone, seismic power dominated the entire recorded bandwidth of 200 Hz-22 kHz at ranges of up to 2 km from the air-gun source. Even at 8-km range seismic power was still clearly in excess of the high background noise levels up to 8 kHz. Acoustic observations of common dolphins during preceding seismic surveys suggest that these animals avoided the immediate vicinity of the air-gun array while firing was in progress, i.e., localized disturbance occurred during seismic surveying. Although a general pattern of localized disturbance is suggested, one specific observation revealed that common dolphins were able to tolerate the seismic pulses at 1-km range from the air-gun array. Given the high broadband seismic pulse power levels across the entire recorded bandwidth, and known auditory thresholds for several dolphin species, we consider such seismic emissions to be clearly audible to dolphins across a bandwidth of tens on kilohertz, and at least out to 8-km range.

Acoustics↗
PubMed1984

Effects of age on auditory awakening thresholds.

Auditory awakening thresholds ( AATs ) were assessed in sleeping men and women at three age levels (18 to 25, 40 to 48, and 52 to 71 years) with a procedure that employed a 5-sec tone in accordance with the up-and-down method. Although age was less influential than individual differences in predicting AAT levels, there was a significant and substantial AAT decline from early adulthood to later life in Sleep Stages 4, 2, and REM. With no variation by sex, this progressive decline was apparent by the 40s in Stages 4 and 2 and was sharpest from one age level to another in Stage 4. Decline was more gradual and delayed in REM, probably because of a sampling artifact based on stimulus incorporation in dreams. These findings help to explain increased sleep disturbance in the later years as a result of diminished intensity of sleep, which makes sleep more difficult to sustain.

Adult↗
PubMedDate not supplied

[Methods of recording threshold auditory evoked potentials].

Presented in the paper are the technique and the device for detecting thresholds of auditory evoked potential (AEP) in the course of objective audiometry. The device reduces basic EEG components in the combined signal thereby increasing AEP-to-EEG ratio. As a result, AEP thresholds can be more effectively detected and measured.

Audiometry, Evoked Response↗