接触枪击噪音后听力的暂时变化。

Pawlaczyk-Luszczyńska Małgorzata, Dudarewicz Adam, Bak Marek, Fiszer Marta, Kotyło Piotr, Sliwińska-Kowalska Mariola

Department of Physical Hazards, Nofer Institute of Occupational Medicine, Lódź, Poland.

Int J Occup Med Environ Health. 2004;17(2):285-93.

OBJECTIVES

Firearm is a common source of impulse noise that may potentially damage hearing organ. It has been suggested that otoacoustic emissions, particularly transient-evoked otoacoustic emissions (TEOAE), might be more sensitive than pure-tone audiometry (PTA) in the assessment of changes to cochlea caused by noise. The aim of this study was to: (i) evaluate exposure to impulse noise from small-caliber weapons, (ii) compare the post-exposure changes in hearing measured by PTA and TEOAE and correlate them with noise parameters.

MATERIALS AND METHODS

The study included 18 male hunters (group I) and 28 candidate policemen (group II) exposed to impulse noise from small firearms during target practices. Group I was unprotected during shooting, whereas group II used commonly available hearing protectors. PTA and TEOAE were performed before and 2-10 min after shooting. Exposure to impulse noise was evaluated by in situ measurements.

RESULTS

Groups I and II were exposed to 3-4 and 4-144 impulses of noise at mean C-weighted peak sound pressure levels of 154 dB and 156 dB, respectively. No post-exposure audiometric threshold shift was observed in group I. Significant reductions of TEOAE levels were found both for the whole response (-2.2 dB SPL) and for 1/2 -octave band responses in the frequency range of 1000-4000 Hz (from -1.6 to -3.0 dB SPL). These changes were not correlated with C-weighted peak sound pressure levels or equivalent-continuous A-weighted sound pressure level. Significant correlation was found for peak sound pressure and maximum sound pressure levels in 1/3-octave bands in the frequency range corresponding with the main part of the acoustic energy of impulses (correlation coefficients r from -0.58 to -0.77, p < 0.05). In group II neither PTA nor TEOAE showed significant hearing impairment after shooting.

CONCLUSIONS

The results show that even short-term exposure to impulse noise from small-calibre firearms might cause temporary hearing impairment measured by TEOAE. Therefore, the use of earmuffs is strongly recommended, because most of them seem to effectively attenuate impulse noise from small-calibre firearms.

目的

枪支是常见的脉冲噪声源，可能会对听觉器官造成潜在损害。有人提出，耳声发射，特别是瞬态诱发耳声发射（TEOAE），在评估噪声引起的耳蜗变化方面可能比纯音听力测试（PTA）更敏感。本研究的目的是：（i）评估小口径武器脉冲噪声的暴露情况；（ii）比较暴露后通过PTA和TEOAE测量的听力变化，并将其与噪声参数相关联。

材料与方法

该研究包括18名男性猎人（第一组）和28名候选警察（第二组），他们在靶场练习期间暴露于小型火器的脉冲噪声中。第一组在射击时未采取防护措施，而第二组使用了常用的听力保护器。在射击前以及射击后2 - 10分钟进行PTA和TEOAE检测。通过现场测量评估脉冲噪声的暴露情况。

结果

第一组和第二组分别平均暴露于3 - 4次和4 - 144次噪声脉冲，平均C加权峰值声压级分别为154 dB和156 dB。第一组未观察到暴露后听力阈值偏移。在整个反应中（-2.2 dB SPL）以及在1000 - 4000 Hz频率范围内的1/2倍频程带反应中（从-1.6到-3.0 dB SPL），TEOAE水平均有显著降低。这些变化与C加权峰值声压级或等效连续A加权声压级无关。在与脉冲声能主要部分相对应的频率范围内的1/3倍频程带中，峰值声压和最大声压级之间存在显著相关性（相关系数r为-0.58至-0.77，p < 0.05）。在第二组中，射击后PTA和TEOAE均未显示出明显的听力损伤。