Short-term music-induced hearing loss after sound exposure to discotheque music: The effectiveness of a break in reducing temporary threshold shift

Objective: To investigate the effect of a break in music exposure on temporary threshold shifts. Design: A cross-over design where subjects are exposed to dance music for either two hours consecutively, or exposed to two hours of dance music with a one-hour break in between. Outcome measure was the change in hearing threshold, measured in 1-dB steps at different time points after ending the music. Study sample: Eighteen normal-hearing subjects participated in this study. Results: Changes in pure-tone threshold were observed in both conditions and were similar, regardless of the break. Threshold shifts could be averaged for 1000, 2000, and 4000 Hz. The shift immediately after the ending of the music was 1.7 dB for right ears, and 3.4 dB for left ears. The difference between left and right ears was significant. One hour after the exposure, right ears were recovered to baseline conditions whereas left ears showed a small but clinically irrelevant remaining shift of approximately 1 dB. Conclusions: The advice to use chill-out zones is still valid, because this helps to reduce the duration to the exposure. This study does not provide evidence that a rest period gives an additional reduction of temporary threshold shifts.