Research Paper Volume 13, Issue 9 pp 12587—12606

Neural presbycusis at ultra-high frequency in aged common marmosets and rhesus monkeys

Effects of age on auditory function in rhesus monkeys. (A) Age-related changes in auditory thresholds determined by ABR. Data are presented as mean ± SEM. Significant differences in ABR threshold between the groups are marked. Compared to 2-10 year-old animals, ABR thresholds increased in aging rhesus monkeys from 8-32 kHz. ABR thresholds increased at 22 and 32 kHz compared aging monkeys with 11-17 y.o. ones. *P B) Scatter plot and corresponding regression line and regression equation for the relationship between ABR amplitudes (nV) and ages (years) of 40 individual rhesus monkeys at a frequency of tone burst stimuli of 22 kHz (R-squared linear= 0.1379, P=0.0183). (C) Scatter plot and corresponding regression line and regression equation for the relationship between ABR latencies (ms) and ages (years) of the 40 rhesus monkeys at a frequency of 22 kHz (R-squared linear= 0.1010, P=0.0456). (D) Association between age and auditory thresholds determined by DPOAE in rhesus monkeys. Data are presented as mean ± SEM. *P

Figure 6. Effects of age on auditory function in rhesus monkeys. (A) Age-related changes in auditory thresholds determined by ABR. Data are presented as mean ± SEM. Significant differences in ABR threshold between the groups are marked. Compared to 2-10 year-old animals, ABR thresholds increased in aging rhesus monkeys from 8-32 kHz. ABR thresholds increased at 22 and 32 kHz compared aging monkeys with 11-17 y.o. ones. *P < 0.05; **P < 0.01; ***P < 0.001 by two-way ANOVA for comparisons of ABR thresholds in 2-10-year-old and 11-17-year-old rhesus monkeys. (B) Scatter plot and corresponding regression line and regression equation for the relationship between ABR amplitudes (nV) and ages (years) of 40 individual rhesus monkeys at a frequency of tone burst stimuli of 22 kHz (R-squared linear= 0.1379, P=0.0183). (C) Scatter plot and corresponding regression line and regression equation for the relationship between ABR latencies (ms) and ages (years) of the 40 rhesus monkeys at a frequency of 22 kHz (R-squared linear= 0.1010, P=0.0456). (D) Association between age and auditory thresholds determined by DPOAE in rhesus monkeys. Data are presented as mean ± SEM. *P < 0.05 by two-way ANOVA for comparisons of DPOAE thresholds in 2-10-year-old and 18-25-year-old animals.