Figure 4: Protection from noise injury. The levels of 2f1 - f2 as a function of f2 frequency (DP-gram; L1/L2 = 65/55) are shown for each treatment group at baseline and 1 day post-noise exposure. The vertical gray bar in this and all figures represent the frequency range of the damaging noise. Both the noise-only group and the CAE+noise group were exposed in the same noise exposure chamber at the same time. Note that the CAE+noise group exhibited better (higher) levels than the noise only group at 1 day post-noise exposure. Errors bars are standard errors of the means.