The influence of noise exposure on endolymphatic hydrops. An experimental study.

The influence of noise exposure on endolymphatic hydrops was examined morphologically. Endolymphatic hydrops was produced experimentally in guinea pigs by means of endolymphatic sac obliteration. Approximately 2 months later, the animals were subjected to noise exposure for 2 h and, as a result, the following findings were obtained: Vascular and circulatory disturbances in the 3rd and 4th turns of cochlea, i.e., vasoconstriction-like changes in the upper coiled arterioles and capillaries in the stria vascularis, as well as blood cell sludge. In addition, the outer hair cells in Corti's organ at the same turns disappeared sporadically. No changes were observed in the opposite, control, ear of the same animal which was free from endolymphatic hydrops. On the basis of these results, it is argued that endolymphatic hydropic ears are highly vulnerable to noise exposure.