Human cochlear changes in noise induced hearing loss.

The temporal bone histopathological findings in 14 ears with noise induced hearing loss are presented. The morphological changes consist mainly of hair cell loss, which is more severe in the 9 mm to 13 mm region of the cochlear duct. Within the area of maximum hair cell loss, there is a greater loss of outer hair cells than of inner hair cells. There is a good correlation between the permanent auditory threshold shifts and the spatial location of the sensory lesion according to the anatomical frequency scale.