Noise exposure and ABR measurements. Exposure of mice to broadband noise (2-10 kHz) of either 108 or 110 dB SPL resulted in elevations of auditory thresholds. Thresholds in Mrps5V338Y/V338Y mutant mice (black bars) were significantly higher after exposure than thresholds in littermates (open bars), (p<0.0001, two-way ANOVA for combined 108 and 110 dB data). Frequencies of 12, 24 and 32 kHz were selected for measurement to cover the mid-frequency to high-frequency regions of the cochlea. n=6 for baseline littermates; n=6 for baseline mutants; n=3 for all noise exposures. 