CHANGES OF AUDITORY FUNCTIONS IN HUMAN SUBJECTS STAYING IN CLOSED ENVIRONMENT

Auditory functions of ten subjects before,during,and after a 90-day staying in a closed en-vironment and exposure to the following factors:noise,temperature,relative humidity,confinement,mental strain and trace of some atmospheric components(CO_2,CO,NO_2,etc.)were studied.Puretone audiograms(both AC and BC),threshold of frequency modulation detection,poststimulationfatigue,threshold of intelligibility,and maximum discrimination score were measured to assess thefunctional state of the auditory system.The relationship between the auditory functions and theenvironmental factors,including noise,was discussed in this paper.     

密闭环境条件下人的听觉功能变化

本文研究了10名受试者在密闭环境条件下听觉功能的变化。环境因素包括噪声、温度、湿度、脑力负荷和某些微量气体成分。受试者的听阈偏移在实验期15—30天后即趋于稳定,在实验终止后15天恢复到原有水平。最大听阈偏移为20—40分贝,主要频率为1000—4000赫,与噪声频谱一致。在实验期90天最大清晰度值下降10％,可懂度阈增高7分贝。音调辨别阈在60—90天持续升高。刺激后疲劳测定表明,尽管实验后15天听阈已恢复,但听觉系统的疲劳状态仍然存在。文中讨论了听觉分析器外周和中枢部分的变化与噪声等环境因素的关系。     

ACOUSTIC IMPEDANCE CHANGES IN THE MIDDLE EAR OF GUINEA PIGS AFTER EXPOSURE TO IMPULSE NOISE AND AIR BLAST

Acoustic impedance changes and hearing threshold shifts after exposure to impulse noise or air-blasts were studied in guinea pigs.Air-blasts were produced by firing of live ammunition in a 100mm caliber gun,with peak SPL ranging from 172.9 to 190.3 dB for differnt groups of animals.Eachexposure consisted of 7—10 impulses.Blast impulses of the same origin were recorded on a tape re-corder and reproduced by playing back through loudspeaker system to serve as the source of impulsenoise.Each exposure consisted of 400 impulses,the peak SPL being 160 dB.Changes in tym-panograms of most animals after exposure to air-blasts suggested that hearing threshold shifts in thisgroup of animals were probably due to impairment of the middle ear.With respect to impulse noise,there was no evidance of severe damage to the middle ear although threshold shifts were obvious.Itwas proposed that inner ear trauma might be responsible for the latter changes.Cases with normal andabnormal tympanograms in the performed experiment we     

脉冲噪声与空气冲击波暴露后豚鼠中耳声阻抗的变化

本文利用豚鼠研究了脉冲噪声和空气冲击波暴露后中耳声阻抗的变化和听阈偏移。空气冲击波为100炮实弹射击,其峰值声压级范围为172.9至190.3分贝,每次暴露计7—10个脉冲。脉冲噪声为100炮脉冲的录音磁带重放(通过扬声器系统),每次暴露计400个脉冲,峰值声压级为160分贝。空气冲击波暴露后,大多数动物鼓膜声顺图的变化提示其听阈偏移可能是由于中耳损伤所引起的。至于脉冲噪声,虽然动物的听阈偏移是明显的,但中耳损伤并不十分严重。很可能脉冲噪声所产生的听阈偏移与内耳损伤有关,本实验还讨论了正常和异常的鼓膜声顺图。