作業者の聴力損失(PTS)の測定ならびにPTSと言語聴力障害との関連

本研究旨在探讨工业噪声暴露对工人永久性听阈偏移（PTS）的影响及其与言语知觉损害的关系。研究和实验结果如下：1.本文对510名噪声作业工人和325名非噪声作业工人的听阈进行了测定。2.每个工人的噪声暴露量是通过个人噪声剂量计测量的，该噪声剂量计在特定的平均时间内给出等效的连续A加权声压级。3.对噪声诱发PTS受试者和正常受试者的单音节词清晰度进行了测量。结果发现，单音节词言语听力测试对听力损伤不敏感。4.在环境噪声和混响条件下，对患有NIPTS的听力障碍者和正常人的三音节词发音进行了测量。结果表明，混响对听力障碍者的言语知觉影响较大。5.设计了模拟复张现象的数字滤波器，合成了假定听力障碍者可能听到的失真人声。6.用正常受试者测量如上所述合成的单音节声音的清晰度，并将结果表示为语音音频图，与恐惧障碍者使用未失真的发声声音的结果进行比较。结果表明，两种声图具有令人满意的一致性。

This study investigates the permanent threshold shift(PTS) of workers induced by industrial noise exposure and the relation between PTS and the impairment of speech perception. The results of the investigations and the experiments are as follows;1. Hearing thresholds of 510 noise-exposed workers and 325 subjects without noise exposure are measured. 2. Noise exposure of each worker is measured by means of indivifual noise dose meter which gives equivalent continuous A-Weighted Sound Pressure Level over the particular averaging time. 3. Articulations of monosyllabic words using the subjects having noise-induced PTS as well as normal subjects are measured. It is found that speech hearing test using monosyllabic words is not sensitive to hearing impairment. 4. Articulations of trisllabic words using the hearing impaired and normal subjects having NIPTS are measured in the presence of ambient noise and in the condition of reverberation. The results show that the hearing impaired are more imfluenced by reverberation in speech perception. 5. Digital filter simulating the recruitment phenomenon is programmed and distroted vocal sounds presumed the hearing impaired might hear are synthesized. 6. Articulations of monosyllabic sounds synthesized as above are measured using normal subjects and the result expressed as speech audiogramme are compared with that of the fearing impaired using notdistorted vocal sounds. The result shows that both audiogrammes are in satisfactory agreement.