Fig. 1.

Auditory brainstem response (ABR) threshold testing through P6mo for CBA and C57 mice. Raw data for the 32 kHz tone burst ABR show an elevated threshold and abnormal wave form in C57 mice from P3mo onwards (A). C57 mice demonstrate a significantly elevated hearing threshold at a 32 kHz tone burst ABR from P1mo onwards, but not for 8, 16 kHz, or clicks (B). C57 mice at P6mo show a clear defect in outer hair cell function from the mid-to-high frequency region, which has been observed as low distortion product otoacoustic emission (DPOAE) levels compared with the CBA mice (C). ^*P<0.05. NF: noise floor.