Hearing threshold shifts and recovery in harbor seals (Phoca vitulina) after octave-band noise exposure at 4 kHz

Some individuals who have been exposed to infrasound have complained of subjective symptoms which seemed to be an offshoot of the changes in vestibular function. This study was undertaken in order to clarify the latter assumption by observing the change of mode of postural control upon subjecting to infrasound vis-a-vis noise exposure. Thirty-four healthy males were subjected to a wide octave-band noise, 16 Hz and 5 Hz at 95 dB for 5 minutes. Their body sway was measured before and during exposure. The trace-length and the power percentage by spectral analysis were determined from their body sway. Our present findings show that the mode of body sway was temporarily confused at the time of switchover from opening to closing of the subject's eyes in the pre-exposed condition. This confusion was inhibited by exposure to infrasound. No effects were however observed upon exposure to noise. These results are taken to suggest that the excitability of the vestibulum was accelerated upon exposure to infrasound, whether or not the subjects perceived any sensations.

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Temporary hearing threshold shift in harbor seals (Phoca vitulina) due to a one-sixth-octave noise band centered at 40 kHz

The Journal of the Acoustical Society of America ◽

10.1121/10.0000908 ◽

2020 ◽

Vol 147 (3) ◽

pp. 1966-1976 ◽

Cited By ~ 1

Author(s):

Ronald A. Kastelein ◽

Cosmin Parlog ◽

Lean Helder-Hoek ◽

Suzanne A. Cornelisse ◽

Léonie A. E. Huijser ◽

...

Keyword(s):

Hearing Threshold ◽

Phoca Vitulina ◽

Threshold Shift ◽

Harbor Seals ◽

Noise Band

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Temporary Threshold Shifts Produced by Exposure to High-Frequency Noise

Journal of Speech and Hearing Research ◽

10.1044/jshr.1503.624 ◽

1972 ◽

Vol 15 (3) ◽

pp. 624-631 ◽

Cited By ~ 25

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.

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Decay of Temporary Threshold Shift in Noise

Journal of Speech and Hearing Research ◽

10.1044/jshr.1602.267 ◽

1973 ◽

Vol 16 (2) ◽

pp. 267-270 ◽

Cited By ~ 5

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.

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