Large Vestibular Aqueduct Syndrome
The enlarged vestibular aqueduct syndrome is operationally defined as a sudden and/or progressive sensorineural hearing loss in a patient with computed tomographic (CT) evidence of an enlarged vestibular aqueduct. Such enlargements may be seen in normally hearing individuals, but when seen in individuals with sensorineural hearing loss, the operational definition is partially met. If the hearing loss in these individuals progresses, the definition is fully met. Some of these patients become profoundly hearing impaired and require cochlear implantation.
The exact mechanism of how this anatomic finding relates to the hearing loss is unknown; however, it might be associated with the well known and described Mondini malformation, which has a host of abnormalities of development within the vestibular and cochlear labyrinth. Abnormalities in chromosomal region 7q31 seem to be associated with this syndrome; the exact significance of this is yet to be determined.
Treatment at this point is confined to hearing rehabilitation and educational structures that help hearing impaired individuals.
I recommend reading: Miyamoto, Bradford, Wynne, and Kirk's article in the Laryngoscope, Volume 112, Part 7, July 2002, pages 1178-1182, titled ''Cochlear Implantation With Large Vestibular Aqueduct Syndrome''.