Ameliorative effects of exposing DBA/2J mice to an augmented acoustic environment on histological changes in the cochlea and anteroventral cochlear nucleus.

DBA/2J (D2) mice, which exhibit very early progressive sensorineural hearing loss, were treated nightly with an augmented acoustic environment (AAE) initiated before the onset of hearing, and consisting of repetitive bursts of a 70-dB sound pressure level (SPL), 4-25 kHz noise band. At 55 days of age, AAE-treated mice exhibited less elevation of auditory brainstem response thresholds, fewer missing hair cells, and greatly reduced loss of anteroventral cochlear nucleus (AVCN) volume and neuron number compared to untreated control mice. It was hypothesized that the central neuroprotective effect was associated with increased afferent input to AVCN neurons evoked by the AAE as well as a healthier cochlea.