Audiometric studies versus predictions of drastic deteriorations of hearing protectors' noise attenuation due to reduced wearing time: Misjudgments by standards based on the energy-equivalence principle.

Background: International standards based on the energy-equivalence principle predict a drastic deterioration of hearing protectors' noise attenuation if the protector is not worn for only brief time periods.

Objective: Therefore, studies in a laboratory setting were carried out to examine whether corresponding temporary threshold shifts (TTS) due to realistic noise exposures can be found.

Methods: Ten test subjects (Ss) were exposed to two reference exposures of 94 dB (A) for 1 h and 97 dB (A) for 1/2 h.