The influence of round window membrane (RWM) rupture on the cochlear potentials was investigated with special reference to the EP. The RWM of the guinea pig was incised with a needle or a glass micropipette and the EP as well as the CM and AP of second cochlear turn were recorded before and after the operation.
Although the EP suffered considerable decline in five of 11 animals, it showed little change in the remaining six animals. Changes of the CM and AP seemed parallel to that of the EP. This study suggests that hearing loss can be caused by the tear of the RWM, however, it does not necessarily happen even in the presence of the obvious rupture.
