Cochlear Pathology with Experimental Acoustic Trauma
1976 Volume 19 Issue 2 Pages 67-77
Details
1976 Volume 19 Issue 2 Pages 67-77
Cochlear pathology due to noise exposure were investigated by chiefly experimental approaches. Among a variety of the experimental procedures were predominantly employed optical microscopy and scanning and transmission electron microscopy for morphological examination and evoked response audiometry.
Experimental animals used were guinea-pigs and mice. They were exposed to pure tone of 500, 2, 000 and 4, 000Hz with 110-120 dB SPL for various durations from 10 minutes to 15 days consecutively, or to a shock sound. Immediately and in different periods of time within 2 months after the completion of the exposure, the cochlea was examined and the extent of the lesions ranging initial sign to advanced degeneration was minutely clarified.
Besides, it was demonstrated that the immature cochlea is less affected by sound injury while vulnerability of the mature cochlea is much intensified by concomitant medication with aminoglycoside drugs.
Changes in auditory function were studied by evoked response auditometry at the stage in which no morphological change was found, and, as a result, a transient increase in amplitude of the course of recovery from the sound injury.
