[Acute sensory deafness originating from experimental double-membrane rupture].

Combined rupture of Reissner's membrane and the round window membrane (double-membrane rupture) as a cause of acute profound sensorineural hearing loss was investigated in guinea pigs. Action potentials (APs) of the cochlear nerve in response to tone pip stimuli (1, 2, 4, 8kHz) were recorded before and after rupture of Reissner's membrane at each 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 study to confirm the rupture of Reissner's membrane. The ears with double-membrane rupture showed a larger decrease in AP amplitude at all test frequencies than did control ears with round window rupture alone. The ears in which Reissner's membrane was ruptured at the second turn showed more a pronounced decrease in AP amplitude than those ruptured at the third and apical turns. It was concluded that double-membrane rupture could be a cause of sudden deafness, but that the disturbance of cochlear function depends on where Reissner's membrane ruptures.