FIG. 3.

α₂–Na,K–ATPase^+/− single heterozygote mice exhibit progressive hearing loss with age. a ABR thresholds again show an initial mild hearing loss at 5–10 weeks of life with significant and progressive deterioration with age, displayed at bi-weekly intervals to age 60 weeks. Progressive hearing loss occurs comparably across all tested stimulus frequencies: click, 8, 16, and 32 kHz. *p < 0.05, statistically significant difference compared to baseline threshold at 5–10 weeks; error bars standard deviation. b Representative DP gram at 75 weeks, showing absence of DPOAE levels for 2f₁ − f₂ distortion products across the frequency range. 65 dB SPL DP gram is representative and is shown. DPOAE were absent at 55 and 75 dB SPL as well (data not shown)