The large vestibular aqueduct syndrome.

The hypocycloidal polytomographic temporal bone studies performed on 2683 patients were reviewed, and the radiographic appearance of the vestibular aqueduct was evaluated. Within this group of 5366 ears, forty-seven ears (1%) in twenty-six patients demonstrated a large vestibular aqueduct (diameter greater than 1.5 mm). A review of the relevant embryology, anatomy, and physiology is reported. A discussion of hypocycloidal polytomography and computed tomography of the temporal bone as well as a discussion of the Mondini dysplasia is also presented. The twenty-six patients underwent a battery of audiometric and vestibular function tests. These data were compiled and correlations made, allowing for a more complete characterization of the large vestibular aqueduct syndrome.