Superior semicircular canal dehiscence: a series of 13 cases.

Increasingly more detailed imaging techniques have recently highlighted the frequent occurrence of bony labyrinthine dehiscence. Among them, superior canal dehiscence (SCD) has been described in a number of cases presenting different features. Here, we report a series of 13 cases, in which the detection of vestibular evoked myogenic potentials (VEMPs) in response to stimuli of abnormally low intensity as compared to normal responses led us to suspect the presence of a 'third window effect'. An accurate HRCT investigation allowed the diagnosis of SCD. Anamnestic and symptomatologic differences seem difficult to explain, although in our opinion a dural rupture could be at the basis of the onset of pathologic manifestations after many years of silence of a probably malformative condition.