The progression of hearing loss in the early stages of sudden deafness.

The pathogenesis of sudden deafness is still not known. Therefore, to clarify its pathophysiology, it is important to know whether the progression of hearing loss occurs in the early stage of sudden deafness. The subjects were 11 patients with sudden deafness showing the progression of hearing loss by pure tone audiometry after the onset of the initial attack of hearing loss. The progression of hearing loss was mostly observed within 4-7 days after the onset of the initial attack. Average hearing loss in initial audiometry was severe and the recovery was poor in the majority of cases. An exploratory tympanotomy was performed in five cases and revealed one case of perilymphatic leak from the round window and another case of suspected round-window membrane rupture. As far as the causes of the progression of hearing loss in the early stage of sudden deafness are concerned, the following could be considered (1) aggravation of viral labyrinthitis, (2) aggravation of the vascular lesion of the inner ear, and (3) rupture of the membranous labyrinth of window(s).