ABSTRACT
In advanced cases of occupational hearing loss, it may be difficult to distinguish the portion of the loss caused by noise from the portion that is caused by presbycusis. If, in a specific case, a reasonably good hearing level can be recorded in the frequencies >8000Hz, the diagnosis could be noise-induced hearing loss. However, if the threshold level at 8000 Hz is about the same or worse than it is at 4000 Hz, then causes other than noise exposure should be considered, unless the employee was exposed for many years to high-frequency, high-intensity noise such as that from chipping and high-pressure air. Frequencies > 8000 Hz also should be tested.
