Figure 1.

Elevated ABR thresholds and progression of hearing loss in double heterozygous mice. Average ABR thresholds for broadband clicks and 8, 16 and 32 kHz pure-tone stimuli are shown for 12 +/Pcdh15^av-3J single heterozygotes (cross-hatched bars), five +/Cdh23^v-2J single heterozygotes (diagonally marked bars) and 33 Cdh23^v-2J +/+ Pcdh15^av-3J double heterozygous mice (black bars) tested at 6–7 months of age. ABR threshold values below 55 (click), 50 (8 kHz), 35 (16 kHz) and 60 (32 kHz) dB SPL are considered within the normal range for mice (15). The maximum amplitude presented for each test stimulus was 100 dB. Standard errors are indicated for each threshold mean (A). For each test stimulus, the average ABR thresholds of two +/Pcdh15^av-3J single heterozygous controls (squares connected by dashed line) and seven Cdh23^v-2J +/+ Pcdh15^av-3J double heterozygotes (diamonds connected by solid line) are plotted for successive tests performed at 22, 89, 153 and 175 days of age. Standard errors are indicated for each threshold mean (B).