Fig. 4

Age-related hearing impairments and morphological correlation. a, b Age-related elevation of mean ABR thresholds (a) and reduction of DPOAE amplitudes (b). Red and blue circles represent the values of mean ABR threshold at 16 kHz (in a) and the mean DPOAE amplitude at 16 kHz (in b) for each mouse and each time point. These values were then used to perform a linear regression, allowing the measurement of threshold elevation or amplitude reduction per month and the calculation of Pearson correlation coefficients. c Time course of ABR threshold increase and DPOAE amplitude decrease in the p43^−/− mice. The left ordinate represents the mean difference (Δ) in ABR thresholds between p43^−/− and WT mice. The right ordinate represents the mean difference (Δ) in DPOAE amplitudes between p43^−/− and WT mice. The abscissa represents the time in months. The data were derived from a and b. d Elevation of ABR thresholds (black circles) at 16 kHz relating to the percentage of OHC (cyan circles), IHC (magenta circles), and SGN survival (green circles) in the cochlear basal region from p43^−/− (solid line) and WT (dotted line) mice aged 1, 6, and 12 months. The left Y-axis represents the mean percentage of remaining OHCs, IHCs and SGNs related to 1-month-old WT mice. The right Y-axis represents the values of mean ABR threshold