Johnson D L, Nixon C W, Stephenson M R
Aviat Space Environ Med. 1976 Sep;47(9):987-90.
The effects were examined of various patterns of interruption--of continuous noise by periods of quiet--on the growth and recovery of temporary threshold shift of hearing over an exposure period of 24 h. Monaural thresholds of hearing were measured prior to, during, and following exposure to a pink noise at a level of 85 dBA and to four conditions in which the pink noise was interrupted with various on-off ratios. The interrupted exposure patterns and levels were adjusted to make their average levels equivalent to 85 dBA. Among the results: 1) the growth of TTS clear.ly reached an asymptote for all interrupted exposure conditions, even when the TTS was as small as 5 dB, 2) the interrupted exposures produced lower asymptotic levels than the continuous exposure with the same amount of energy, and 3) the TTS recovery patterns were essentially the same at 1 h and beyond, for all conditions. These data support the concept that, following a long exposure, one should be provided at least as much time for recovery as the duration of the exposure.
研究了各种间断模式——即通过安静时段打断连续噪声——对24小时暴露期间听力暂时阈移的增长和恢复的影响。在暴露于85分贝A的粉红噪声之前、期间和之后，以及在粉红噪声以各种开关比被打断的四种条件下，测量了单耳听力阈值。调整间断暴露模式和强度，使其平均强度相当于85分贝A。结果如下：1）对于所有间断暴露条件，即使暂时阈移小至5分贝，其增长也明显达到了渐近线；2）与具有相同能量的连续暴露相比，间断暴露产生的渐近水平更低；3）在所有条件下，1小时及以后的暂时阈移恢复模式基本相同。这些数据支持这样一种观点，即在长时间暴露之后，应该给予至少与暴露持续时间相同的恢复时间。
