[Effect of oxygen in the tympanum on inner ear function (author's transl)]

Possible effects of extreme variations of oxygen concentration from 0% to 100% in the tympanic lumen on inner ear function were investigated through animal experiments. The experiments were performed with Ketanest anaesthetized cats under short-time acoustic irradiation (3 min 115 dB, pink noise). Inner ear function was measured by means of the stapedius reflex audiometry. On the nitrogen-flushed side (pO2 approx. 0%), the stapedius reflex threshold dropped significantly more after high-frequency irradiation than on the O2-flushed side. Even without acoustic irradiation the stapediusreflex threshold clearly recedes with the tympanic cavity being nitrogen-flushed. This shows that inner ear function in the cochlear base area depends on oxygen concentration in the tympanic lumen. It is pointed out that interrelations between disturbances of tubal and tympanic functions on the one hand, and internal ear function on the other hand may exist.