The Pathological Types of Cochleo-Saccular Degeneration

Abstract

A pathological study of the specimens in our temporal bone library indicates that there are three conditions in which cochleo-saccular degeneration is found: (1) genetically inherited anomaly; (2) viral diseases; and, (3) aging. A number of mammals present inherited forms of labyrinthine agenesis or degeneration. These include various mutant strains of mice, waltzing guinea pigs, albino cats, and Dalmatian dogs. Cochleo-saccular atrophy is a common pathological finding in deafness due to maternal rubella, postnatally acquired measles, mumps, and sudden deafness. Involvement of the saccnle as well as the cochlea as an atrophic process in aging has r:ot been reported previously. Specinlens from an aged cat, dog, and human suffering from slowly progressive deafness show atrophic changes in the cochlea and saccule with normal utricle and semicircular canals. In demonstrating a greater susceptibility to injury, the pars inferior (cochlea and saccnle) abides by the biological rule that the phylogenetically newer systems in an organism exhibit a greater su-ceptibility to abuse than do older systems. It seems likely that the cochlea and saccnle share a common denominator, phylogenetically determined, which may be metabolic, cytochemical, enzymatic, or possibly micro-anatomical, and which makes theni jointly susceptible to certain genetic alterations, viral diseases, and aging.