Temporary Threshold Shift following 24-Hour Noise Exposure

1977 ◽  
Vol 86 (6) ◽  
pp. 821-826 ◽  
Author(s):  
William Melnick
Keyword(s):  
Noise Level ◽  
Noise Exposure ◽  
Sound Field ◽  
Threshold Shift ◽  
Exposure Level ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Straight Line ◽  
Hearing Thresholds ◽  
Continuous Noise

Nine men were exposed to 24 hours of continuous noise in a sound field. The noise was an octave band centered at 4 kHz at levels 80 and 85 dB. Hearing thresholds were measured monaurally at 11 test frequencies ranging from 250 to 10000 Hz before, during, and after exposure. Temporary threshold shift (TTS) reached maximum levels at 8 to 12 hours of exposure. Maximum TTS occurred at 4 and 6 kHz. Mean asymptomtic threshold shifts (ATS) resulting from the 80 dB exposure level were 9.3 dB for 4 kHz and 7.2 dB for 6 kHz. For the 85 dB noise level, these threshold shifts were 17.8 dB and 14.6 dB respectively. The increase in ATS with increase of noise level for these two frequencies could be fitted with a straight line having a slope of 1.6.

Asymptotic Threshold Shift (ATS) in Man from 24 Hour Exposure to Continuous Noise

1974 ◽  
Vol 83 (6) ◽  
pp. 820-828 ◽  
Author(s):  
William Melnick ◽  
Michael Maves
Keyword(s):  
Growth Pattern ◽  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Time Intervals ◽  
Small Magnitude ◽  
Slow Development ◽  
Hearing Thresholds ◽  
Continuous Noise

Ten men were exposed to a 300–600 Hz band of noise at an octave-band-level of 90 dB in a sound field for a period of 24 hours. Hearing thresholds were measured in one ear at 11 test frequencies ranging from 125 to 8000 Hz prior to exposure and at selected time intervals during and after exposure. Temporary threshold shift (TTS) appeared to reach asymptotic levels by 12 hours of exposure. Maximum TTS was approximately 11 dB and occurred at 500, 750 and 1000 Hz. TTS was appreciable at 1500 Hz amounting to 7 dB and was less than 5 dB at other frequencies. The growth pattern of TTS was triphasic; slow development during the first two hours of exposure, a rapid increase from 2 to 8 hours, and then apparently reaching an asymptote by the twelfth hour. Recovery was prolonged for the relatively small magnitude of TTS, requiring 24 hours before most of the subjects returned to preexposure threshold levels. Asymptotic TTS (ATS) showed dependence on preexposure threshold hearing levels.

Temporary Threshold Shifts Produced by Exposure to High-Frequency Noise

1972 ◽  
Vol 15 (3) ◽  
pp. 624-631 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo
Keyword(s):  
High Frequency ◽  
Noise Exposure ◽  
Sound Field ◽  
Acoustic Properties ◽  
Threshold Shift ◽  
Maximum Effect ◽  
Frequency Noise ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise

Four chinchillas, monaural and trained in behavioral audiometry, were exposed for 24 days in a diffuse-sound field to an octave-band noise centered at 4.0 k Hz. The octave-band levels (OBL re 0.0002 ubar) were 57 dB for Days 1 to 6; 65 dB for Days 7 to 12; 72 dB for Days 13 to 18; and 80 dB for Days 19 to 24. At regular intervals throughout the noise exposure each animal was removed from the noise and threshold measurements were made. For each level of noise, temporary threshold shift reached an asymptote. In the frequency region of maximum effect, the relation between temporary threshold shift and the level of the noise is given by the equation TTS 4 ∞ = 1.6 (OBL-47) where TTS 4 ∞ is the temporary threshold shift at asymptote measured at a postexposure time of four minutes. These results for a noise centered at 4.0 k Hz in combination with those results for a noise centered at 0.5 k Hz suggest that bands of noise produce equal TTS 4 ∞ when the levels of the noises are equated for the acoustic properties of the external ear (including the head) and the inner ear.

Decay of Temporary Threshold Shift in Noise

1973 ◽  
Vol 16 (2) ◽  
pp. 267-270 ◽  
Author(s):  
John H. Mills ◽  
Seija A. Talo ◽  
Gloria S. Gordon
Keyword(s):  
Sound Field ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise ◽  
Lower Asymptote

Groups of monaural chinchillas trained in behavioral audiometry were exposed in a diffuse sound field to an octave-band noise centered at 4.0 k Hz. The growth of temporary threshold shift (TTS) at 5.7 k Hz from zero to an asymptote (TTS ∞ ) required about 24 hours, and the growth of TTS at 5.7 k Hz from an asymptote to a higher asymptote, about 12–24 hours. TTS ∞ can be described by the equation TTS ∞ = 1.6(SPL-A) where A = 47. These results are consistent with those previously reported in this journal by Carder and Miller and Mills and Talo. Whereas the decay of TTS ∞ to zero required about three days, the decay of TTS ∞ to a lower TTS ∞ required about three to seven days. The decay of TTS ∞ in noise, therefore, appears to require slightly more time than the decay of TTS ∞ in the quiet. However, for a given level of noise, the magnitude of TTS ∞ is the same regardless of whether the TTS asymptote is approached from zero, from a lower asymptote, or from a higher asymptote.

Combined Effects of Noise and Cisplatin: Short- and Long-Term Follow-Up

1992 ◽  
Vol 101 (12) ◽  
pp. 969-976 ◽  
Author(s):  
Göran F. E. Laurell
Keyword(s):  
Noise Exposure ◽  
Threshold Shift ◽  
Combined Effects ◽  
Temporary Threshold Shift ◽  
Short Term ◽  
Hearing Thresholds ◽  
Long Term Follow Up ◽  
Short And Long Term

The combined effects of noise exposure and intravenous cisplatin injection on electrophysiologic hearing thresholds in guinea pigs were studied with short-term and long-term follow-up. The combined effects on the permanent threshold shift were dependent on the order of exposure. A potentiation was achieved when noise exposure preceded cisplatin injection by 30 minutes or by 3 days. Cisplatin injection 2 or 3 days before noise exposure produced no significant potentiation or inhibition. The combined effects on the temporary threshold shift were not influenced by the sequence of exposure.

Damage Risk: An Evaluation of the Effects of Exposure to 85 versus 90 dBA of Noise

1976 ◽  
Vol 19 (2) ◽  
pp. 216-224 ◽  
Author(s):  
James T. Yates ◽  
Jerry D. Ramsey ◽  
Jay W. Holland
Keyword(s):  
White Noise ◽  
Statistical Difference ◽  
Noise Exposure ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Noise Levels ◽  
Potential Damage ◽  
Full Day ◽  
Damage Risk

The purpose of this study was to compare the damage risk of 85 and 90 dBA of white noise for equivalent full-day exposures. The damage risk of the two noise levels was determined by comparing the temporary threshold shift (TTS) of 12 subjects exposed to either 85 or 90 dBA of white noise for equivalent half- and full-day exposures. TTS was determined by comparing the pre- and postexposure binaural audiograms of each subject at 1, 2, 3, 4, 6, and 8 kHz. It was concluded that the potential damage risk, that is, hazardous effect, of 90 dBA is greater than 85 dBA of noise for equivalent full-day exposures. The statistical difference between the overall effects of equivalent exposures to 85 dBA as compared to 90 dBA of noise could not be traced to any one frequency. The damage risk of a full-day exposure to 85 dBA is equivalent to that of a half-day exposure to 90 dBA of noise. Within the limits of this study, TTS t was as effective as TTS 2 for estimating the damage risk of noise exposure.

scholarly journals Octave Band Technique for Noise Measurement at the Source, Path, and Receiver of Gas Turbines in Oil and Gas Facilities

2022 ◽  
Vol 30 (1) ◽  
pp. 725-745
Author(s):  
Akmal Haziq Mohd Yunos ◽  
Nor Azali Azmir
Keyword(s):  
Gas Turbine ◽  
Noise Level ◽  
Gas Turbines ◽  
Noise Exposure ◽  
Oil And Gas ◽  
Noise Pollution ◽  
Noise Measurement ◽  
Octave Band ◽  
High Noise ◽  
Safety And Health

Noise measurement is essential for industrial usage. However, further attention to preventing noise pollution is needed, especially when working with equipment generating a high noise level, such as gas turbines. This study aims to determine the best way to perform noise measurement and analyze the octave band frequency generated by noise pollution caused by gas turbine equipment. Data from site measurements show that the gas turbines produce more than 85 dB of noise with a Z-weighted measurement. A noise measuring investigation was conducted to obtain the data for the 1/3 octave band. A frequency-domain was used to comprehend the properties of the noise measurement frequency band. The frequency band was classified into three different zones called low, medium, and high frequency, which is useful in noise measurement analysis to identify a viable solution to reduce the noise. On-site sampling was performed at the source, path, and receiver of three separate gas turbine locations within oil and gas operations. The 1/3 octave band data collection results at the sound source, path, and receiver demonstrate the noise level distribution at the perimeter of gas turbine installations in the low and medium frequency ranges. Most of the high noise frequency range is between 250 Hz and 2 kHz for source, path, and receiver. All acquired values are compared to the Department of Safety and Health (Occupational Safety and Health (Noise Exposure) Regulations 2019 in Malaysia. As a result, oil and gas service operators can monitor and take countermeasures to limit noise exposure at oil and gas facilities.

Temporary Threshold Shift and Otoacoustic Emissions after Industrial Noise Exposure

1995 ◽  
Vol 24 (2) ◽  
pp. 137-141 ◽  
Author(s):  
Kari J. Kvœrner ◽  
Bo Engdahl ◽  
Atle R. Arnesen ◽  
Iain W. S. Mair
Keyword(s):  
Otoacoustic Emissions ◽  
Noise Exposure ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Industrial Noise

Noise

2020 ◽  
pp. 1671-1673
Author(s):  
David Koh ◽  
Tar-Ching Aw
Keyword(s):  
Cardiovascular Disease ◽  
Hearing Loss ◽  
Sleep Disturbance ◽  
Cognitive Performance ◽  
Noise Exposure ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Noise Induced Hearing Loss ◽  
Occupational Setting ◽  
Human Ear

Noise can affect hearing in the occupational setting but can have other effects where exposures are non-occupational. For clinical purposes, noise is measured in decibels weighted according to the sensitivity of the human ear (dB(A)). Regardless of source, the effects of overexposure to noise are similar. Initially there is a temporary threshold shift, where reversibility of hearing loss is possible with removal away from further noise. Noise-induced hearing loss occurs following prolonged or intense exposure, with poor prospects for improvement of hearing. The classical audiogram for noise-induced hearing loss shows a 4 kHz dip. Non-auditory effects of prolonged noise exposure include annoyance, sleep disturbance, hypertension, and cardiovascular disease, stress, and impaired cognitive performance. Prevention of noise-induced hearing loss is by reducing exposure to noise at source minimizing exposure time, using hearing protection, and participating in surveillance.

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