A New Concept of the Pathogenesis of Presbycusis

In aging, a progressive apposition of dense connective tissue, osteoid, and bone respectively occurs in the bottom of the internal auditory meatus. It can be seen macroscopically as closure and disappearance of the holes for the nerve bundles in the region of the spiral tract and microscopically always starts in the region of the basal coil and progresses towards the modiolar region. This new-formed tissue compresses the nerve fibers and possibly also the arteries passing through the spiral tract. The result is atrophy first of the corresponding nerve fibers on the periphery of the nerve bundles and later also of the ganglionic cells. It is possible that the compression of the arteries causes, in some cases, atrophy of the stria vascularis.