[Comparison of various methods of evaluating auditory damage caused by chronic acoustic injury]. / Confronto di differenti metodiche di valutazione del danno uditivo da trauma acustico cronico.

The purpose of the present study was to compare the most common hearing damage criteria, based upon pure tone audiometric data. We examined 1086 workers with different intensity and duration of noise exposure. After consecutive selections, 455 subjects, subdivided into four exposure groups, were studied. The 12 considered criteria showed a widespread difference in their sensitivity: the percentage of hearing impaired subjects ranged from 3.3 to 24.2% in the whole population. The most sensitive criteria evaluated the hearing loss at 2 and 4 KHz. The evaluation of the hearing loss at 3 and 6 KHz did not modify the percentage of subjects bearing an handicap. The authors suggest the average hearing loss at 2 and 4 KHz as a criterion to be used for preventing and epidemiological purposes.