MORPHOLOGICAL-CHANGES OF STRIA VASCULARIS IN CONGENITAL HEARING IMPAIRMENT DUE TO MEMBRANOUS LABYRINTH UNDERDEVELOPMENT

Congenital malformations of the inner ear may involve either the bone and membranous labyrinth or the membranous labyrinth alone. The same l abyrinth structures can be affected with an acquired disease, toxaemia or viral labyrinthitis, for instance, with the same or very similar h istologic findings. So far, there have been no studies examining the p ossible morphological changes of stria vascularis in different disease s with sensorineural anomalies. We examined the temporal bones of 16 p atients, from whom audiograms and history data on hearing impairments present at birth or later were obtained previously. When malformation of the membranous labyrinth was caused by a congenital anomaly, three groups of typical changes of stria vascularis were observed: i) pseudo cystic formation which replaced the strial tissue, with dark-stained d eposits: ii) accumulation of endothelial cells or irregularly shaped c ells in the basal coil of the cochlea: and iii) atrophy of the stria v ascularis tissue in all coils. These findings may prove important for accurate diagnostic procedures.