If you or your child is experiencing progressive hearing loss, one of the conditions you may be checked for is Enlarged Vestibular Aqueduct Syndrome. Basically, it means that the channel connecting the inner ear and a cranial space has become larger than normal. In more technical terms, this condition means that the endolymphatic duct is much larger than normal, and there is hearing loss associated with this abnormal size. It may be responsible for some "unknown" causes of hearing loss, as EVAS, also known as LVAS (Large Vestibular Aqueduct Syndrome) is a relatively young syndrome, having been identified in the late seventies. It apparently still is not clear how EVAS causes hearing loss.
What is EVAS?
Characteristics of EVAS
The physical characteristics of EVAS can be seen in radiological scans that show enlarged vestibular aqueducts, where the connecting channel is larger than 1.5 mm.
How Can it be Treated?
Cochlear implantation has been found to be beneficial. If there is any residual hearing, avoiding contact sports may help as EVAS has been associated with trauma.
Has Any Research Been Done?
Quite a bit of research has been done into EVAS/LVAS. An internet search turned up the following studies:
- Otoneurological findings and pathophysiology of large vestibular aqueduct syndrome - An abstract from the Journal of the Association for Research in Otolaryngology (JARO)website.
- A review of the literature on Large Vestibular Aqueduct Syndrome for Teachers of the Deaf and Hard of Hearing - Research article published in the Canadian Association of Educators of the Deaf and Hard of Hearing (CAEDHH) journal, v23 n2-3 p149-55 1997 (ERIC number EJ562601)
- Cochlear implantation in children with large vestibular aqueduct syndrome - Abstract of a research study that found implantation helps children with EVAS/LVAS.
- Non-syndromic hearing loss associated with enlarged vestibular aqueduct is caused by PDS mutations - Abstract of the complete article on this subject, fromHuman Genetics, vol.104 no.2, March 1999, pp. 188-192.
