Underwater temporary threshold shift induced by octave-band noise in three species of pinniped

1999 ◽  
Vol 106 (2) ◽  
pp. 1142-1148 ◽  
Author(s):  
David Kastak ◽  
Ronald J. Schusterman ◽  
Brandon L. Southall ◽  
Colleen J. Reichmuth
Keyword(s):  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise

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.

Temporary threshold shift in pinnipeds induced by octave‐band noise in water

1999 ◽  
Vol 106 (4) ◽  
pp. 2251-2251
Author(s):  
David Kastak ◽  
Brandon L. Southall ◽  
Ronald J. Schusterman ◽  
Colleen J. Reichmuth
Keyword(s):  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Band Noise

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.

THE TEMPORARY THRESHOLD SHIFT OF VIBRATORY SENSATION INDUCED BY HAND-ARM VIBRATION COMPOSED OF FOUR ONE-THIRD OCTAVE BAND VIBRATIONS

1997 ◽  
Vol 200 (5) ◽  
pp. 631-642 ◽  
Author(s):  
K. Nishiyama ◽  
K. Taoda ◽  
H. Yamashita ◽  
S. Watanabe
Keyword(s):  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band

Spectral and Temporal Parameters of Contralateral Signals Altering Temporary Threshold Shift

1974 ◽  
Vol 17 (1) ◽  
pp. 41-50 ◽  
Author(s):  
Raymond S. Karlovich ◽  
Terry L. Wiley
Keyword(s):  
Dynamic Properties ◽  
Broad Band ◽  
Normal Hearing ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Acoustic Reflex ◽  
Contralateral Stimulation ◽  
Band Noise ◽  
Resultant Data ◽  
Contralateral Ear

The test ear of each of nine normal-hearing subjects was exposed for three minutes to a 1000-Hz tone at 110 dB SPL. Either a 4000-Hz tone at 105 dB SPL or a broad-band noise at 100 dB SPL was presented to the contralateral ear during exposure. Four different temporal patterns were used for each contralateral signal: (1) continuous, (2) 18 seconds on/18 seconds off, (3) 1.8 seconds on/1.8 seconds off, and (4) 0.18 seconds on/0.18 seconds off. A control condition, consisting of the absence of contralateral stimulation, also was used. Pre- and postexposure thresholds for the test ear were tracked at a signal one-half octave above the exposure frequency. Resultant data indicated that reduction in temporary threshold shift was greatest for conditions involving rapidly pulsed (1.8 and 0.18 seconds on-off) contralateral signals. We hypothesized that these data were reflective of the dynamic properties of the acoustic reflex. Specifically, we posited that the acoustic reflex manifests less adaptation in response to rapid signal-repetition rates and relatively more adaptation to sustained or slowly pulsed signals.

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 from Prolonged Exposure to Noise

1972 ◽  
Vol 15 (3) ◽  
pp. 603-623 ◽  
Author(s):  
Henry M. Carder ◽  
James D. Miller
Keyword(s):  
Time Constant ◽  
Prolonged Exposure ◽  
Test Tone ◽  
Threshold Shift ◽  
Temporary Threshold Shift ◽  
Octave Band ◽  
Auditory Thresholds ◽  
Zero Values

Eight monaural chinchillas were trained to respond to tones, and their auditory thresholds were measured behaviorally. The animals were then exposed to octaveband noise centered at either 0.5 or 4.0 k Hz for periods of two to 21 days. Octaveband levels (OBL) between 65 and 105 dB SPL were used. The growth of temporary threshold shift (TTS) was measured during brief interruptions in the exposure. TTS increased for the first 24 to 48 hours of an exposure and then reached an asymptote and remained constant for as long as the exposure continued. At asymptote the relation between the TTS and the level of the octave band centered at 0.5 k Hz was TTS 4 ∞ = 1.6 (OBL-65), where TTS 4 ∞ was measured with a test tone of 0.715 k Hz at four minutes after an interruption of the noise. Decay of TTS after termination of the exposure was slow and approximately exponential with a time constant of about 29 hours. Empirically, the time for TTS to decay to near-zero values ranged from three to six days. The course of decay of TTS was independent of the duration of the exposure once asymptote had been reached.

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