[A method for prediction of permanent threshold shift (PTS) (author's transl)].

A new test for noise resistance was performed in persons at the time they started on a job with a high noise level; three years later, the initial test results were compared with the chronic damage caused to their hearing by the noise to which they had been expose. In other words, the test results were correlated with the PTS which had since been acquired. The significance was found to be 5%, proving that this professional disease can be predicted. The test is based on an effect in TTS (Temporary Threshold Shift) experiments which had been overlooked so far: Exposure to a tone of low frequency caused a second TTS in the PTS frequency range. This "dip" in the audiogram is always at the same position, independent of the exposure. The amplitude of this second "dip" does not correlate with that of the well-known large frequency-dependent first "dip", which had so far been used by many authors for prognosis. The knowledge of this fact cannot have any bearing on public health until existing legislation has been modified. At present, a small percentage only of workers employed in a job involving noise are transferred; after due modification of the law involving a meaningful prognostic examination prior to their being accepted for a job, the extent of PTS in the population will depend on the number of candidates accepted for professions involving noise in relation to the total number of persons required.