Temporary threshold shift after exposure to predicted and unpredicted noise.

Abstract

In order to investigate if anticipation of noise could influence individual susceptibility to temporary threshold shift (TTS), an experimental study was carried out comprising 10 voluntary normal-hearing subjects. The noise stimulus consisted of noise bursts centered at 4000 Hz with a duration of one second. Initially, each subject was exposed in a test situation where the noise was presented instantly upon the subject's response (producer). The subject was instructed to respond by pressing a button as fast as possible after an optical stimulation. The rate was approximately 1 noise burst/6 sec and the total number of bursts were 100. The intervals between bursts were randomized. Each individual's exposure time pattern was recorded and used for the second test situation. Here the first exposure was reproduced, but each noise burst presented without notice (consumer). Each subject participated in 5 producer sessions and in 5 consumer sessions. Evaluation of TTS measurements revealed a maximum TTS at 6000 Hz. The mean TTS for all subjects in the two different situations, showed no significant difference and only one subject demonstrated a tendency toward a greater TTS susceptibility in the 'consumer' sessions.