Abstract
Combined rupture of Reissner's membrane and round window membrane (doublemembrane rupture) as a cause of acute profound hearing loss was investigated in guinea pigs. Action potentials (APs) of the cochlea nerve in response to tone pip stimuli (1, 2, 4, 8 kHz) were recorded before and after rupture of Reissner's membrane at the second or third turn of the cochlea. Then the round window was perforated to create leakage of the perilymph. Ninety minutes later, AP was again recorded. After these procedures, the animal was sacrificed for histological examination to confirm the rupture of Reissner's membrane. The ear with rupture at the second turn showed a severe decrement in AP amplitude at all test frequencies. However, in the ear with rupture at the third turn, the increment of AP thresholds ranged between 0 and 15 dB.
