[Behavior of 8000 Hz audiometric threshold in chronic acoustic trauma]

The paper analyzes the 8 KHz threshold in subjects with noise-induced hearing loss. The study group consisted of 315 subjects occupationally exposed to noise and suffering from acoustic trauma, which was considered as a mean threshold of more than 25 dB at 2, 3 and 4 KHz. The mean shape of audiograms was characterized by a neurosensory deficit which was more elevated at 4 and 6 KHz whereas the threshold at 8 KHz was better. However, this pattern was found in 60% of the cases whereas in the remaining 40% the threshold at 8 KHz was worse. Subjects with the most impaired audiometric threshold at 8 KHz were mainly older, although cases were found in a low percentage of younger subjects. The results demonstrate that in individual cases it is impossible, on the basis of the shape of the audiogram, to establish whether a hearing loss is due to noise or age.