Zhu S, Sakakibara H, Yamada S
Department of Public Health, Nagoya University School of Medicine, Japan.
Int Arch Occup Environ Health. 1997;69(6):433-6. doi: 10.1007/s004200050171.
To investigate whether hand-arm vibration and noise have a combined effect on temporary threshold shift (TTS) of hearing among healthy subjects.
Nineteen healthy subjects with an average age of 25.7 (SD 7.7) years were exposed to vibration (30 m/s2, 60 Hz), noise [90 dB(A)] and both, respectively. The subject's right hand was placed on the plate of a vibrator and the right ear exposed to noise via headphones. Subjects were exposed to vibration and/or noise for 3 min and after a 1-min pause the exposure was repeated five times. Hearing thresholds at 1, 4 and 6 kHz were measured during the time periods before, between (during pauses) and after exposure.
Exposure to vibration alone caused almost no hearing threshold changes at every frequency tested. But exposure to noise or a combination of vibration and noise caused a significant increase in TTSs at 4 and 6 kHz. Moreover, exposure to a combination of vibration and noise caused significantly higher TTSs than exposure to noise at 4 and 6 kHz.
The present results demonstrate the combined effects of hand-arm vibration and noise can enhance exposure to hand-arm vibration and noise can enhance the TTS of hearing more than noise exposure, though hand-arm vibration alone may hardly affect TTS.
研究手臂振动和噪声对健康受试者听力的暂时性阈移（TTS）是否具有联合作用。
19名平均年龄为25.7（标准差7.7）岁的健康受试者分别暴露于振动（30米/秒²，60赫兹）、噪声[90分贝（A）]以及两者同时存在的环境中。受试者的右手放在振动器的平板上，右耳通过耳机暴露于噪声中。受试者暴露于振动和/或噪声3分钟，在1分钟的暂停后，重复暴露5次。在暴露前、暴露期间（暂停期间）和暴露后测量1、4和6千赫兹的听力阈值。
单独暴露于振动在每个测试频率下几乎没有引起听力阈值变化。但是暴露于噪声或振动与噪声的组合会导致4和6千赫兹的暂时性阈移显著增加。此外，在4和6千赫兹时，暴露于振动与噪声的组合所导致的暂时性阈移显著高于暴露于噪声。
目前的结果表明，手臂振动和噪声的联合作用会增强听力的暂时性阈移，尽管单独的手臂振动可能几乎不影响暂时性阈移，但与噪声暴露相比，手臂振动和噪声的联合作用对听力暂时性阈移的增强作用更大。
