Audiological evaluation was performed for 184 female weavers (351 ears), were 18~25 years old and have been working under the exposure of 103~105 dBa of machinary noise. With the duration of employment, they were divided into five groups; under 1 year, 1~2years, 2~3 years, 3~4 years and over 4 years.
The following results were obtained;
1) The incidence of noise induced. hearing loss was 39.7% (36.2% of ears) and rapidly increased during first 1~2 years.
2) The average maximum hearing loss on the pure tone audiograms appeared at 4, 000 Hz with about 40 dB of hearing level. The average hearing level at high frequencies (3, 000 Hz~8,000 Hz) showed below 25dB of hearing level in all groups and had the tendency to increased slightly with the duration of working, but the most of hearing losses developed during first one year except at 8, 000 Hz.
3) The average hearing level at speech frequencies were within normal range but the cases of hearing level over 25 dB at 2, 000 Hz was 27.1%.
4) The cases with maximum hearing loss at 4, 000 Hz were 72.7%. But the cases of maximum hearing loss at the other frequencies (3,000 Hz, 6,000 Hz and 8,000 Hz) were also observed and they increased slightly in numbers with the duration of working.
The noise induced hearing loss under the exposure of 103~105 dBA for 5 years, seemed to develop during first 1~2 years and thereafter slightly increased hearing loss was showed but no redarkable changes were observed.
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