[Differential diagnostic reflections on sudden deafness: rupture of the round window membrane].

The rupture of the round window membrane has been the origin of sudden deafness in two cases that are described in this presentation. We are able to verify the rupture of the round window membrane before surgery by using differential diagnostic criteria, though there existed only relative slight hearing losses of about 40 dB. After surgery we found normal hearing in one case and a decreased hearing loss in the other. Vestibular symptoms have been leading to the diagnosis in both cases and the middle ear effusion in one case.