Abstract
In 115 patients with congenital or early-onset bilateral profound sensorineural deafness studied radiographically, 17 patients with labyrinthine malformations were found.
The mild type of malformation consisted of hypoplasia of the lateral semicircular canals, the shortening of the hight of the cochlea. In the severe types, the anterior semicircular canals were involved, and the cochlea showed a basal turn-like cavity. In the most severe type, no semicircular canals were developed and the cochlea appeared as a small protrusion from the vestible-like cavity, or was entirely absent.
In the present cases, labyrinthine malformations were found as combinations of the various degrees of hypoplasia of the cochlea and semicircular canals.
There were eight cases with the narrowing of the internal auditory canals, and four cases with abnormaly wide canals.
Three cases with labyrinthine malformations were suspected to be genetical. It was presumed that the genetic heterogeneity of the profound sensorineural deafness can be partly detected by clinical studies of labyrinthine malformations.
