A total of 96 mice from two inbred and two hybrid strains were tested for TTS (temporary threshold shift) and PTS (permanent threshold shift) using electrophysiological procedures for auditory brain-stem responses. Testing continued for up to 3 months following 2 h of exposure to 110-dB broadband noise. The inbred and hybrid strains carrying genes for age-related hearing loss showed TTS almost equal to their PTS ``thus anticipating their tendency to hearing loss.`` On the other hand, the inbred and hybrid strains not carrying those genes showed considerable recovery from their original TTS losses. Those with age-related hearing genes were very susceptible to noise-induced PTS. An additional effect was the presence of strong correlations between TTS and PTS for both inbred strains, but no correlation for the two hybrid strains. Noise exposure history plays a role in the noncorrelations between TTS and PTS typically found in humans. Could genes influence correlation between TTS and PTS in humans?