[Evaluation of the degree of temporary shift in auditory threshold at extended high-frequencies in relation to the efficiency of the organ of hearing].

Temporary threshold shift measurements were taken at extended high frequencies range up to 20 kHz after the first day of work at noise (TTSI) and after a week of work (TTSII) at permanent noise exceeding allowable standards. 87 workers of the "Baildon" steel mill in Katowice were examined. The audiometric threshold examination was carried out after a 40-hr lay-off. Altogether 522 audiograms were done, yielding 4872 results. TTS magnitude was followed as dependent on the hearing organ functioning. TTS increase was found to be reversely dependent on the P.P. threshold values set up prior to noise exposure. The study of the temporary threshold shift for P.P. at extended range of higher frequencies is useful in the prevention of acoustic trauma, especially when meaning the selection of those oversusceptible to noise.