Human Temporary Threshold Shift and Recovery from 24 Hour Acoustic Exposures
AIR FORCE AEROSPACE MEDICAL RESEARCH LAB WRIGHT-PATTERSON AFB OH
Pagination or Media Count:
The effects on hearing sensitivity of 24 hour monotic exposures to a narrow band noise with the center frequency at 1000 Hz at sound intensities of 80, 85, and 90 dBA were evaluated. Automatic audiometry was used to assess changes in hearing from baseline levels for six test frequencies during exposure and during subsequent recovery. Among the results 1 TTS Temporary Threshold Shift growth and recovery was present for 1000, 1500, and 2000 Hz test frequencies only, 2 TTS reached a maximum or asymptote between 8 and 16 hours exposure, 3 TTS induced by the 85 and 90 dBA exposure levels exceeded the limits specified by CHABA Committee on Hearing, Bioacoustics and Biomechanics damage risk criteria and 4 long duration exposures of 85 and 90 dBA require at least 24 hours of rest prior to subsequent exposure.
- Anatomy and Physiology