Evoked potential correlates of genetic progressive hearing loss. Age-related changes from the ear to the inferior colliculus of C57BL/6 and CBA/J mice.

Volume-conducted auditory evoked potentials were simultaneously measured from the level of the ear to the inferior colliculus of mice. The C57BL/6 mouse, which displays genetic sensorineural progressive hearing loss, was compared with the CBA/J mouse. At 50 days post partum, amplitudes of the summating potential (SP) and cochlear microphonic (CM) were lower in the C57BL/6 genotype, and they decreased progressively with age. Fifty days later, changes were seen in responses from the auditory nerve and cochlear nucleus of this mouse. By 200 days of age, the C57BL/6 had a "recruitment" pattern at CNS regions, but not at the auditory nerve.