Large vestibular aqueduct syndrome (LVAS) - A guide to Hearing Loss

This long sounding name is given to a condition in which the certain structures within the inner ear become swollen and enlarged. This can result in fluid flowing back into these structures which causes hearing loss. What is the ‘vestibular aqueduct?’ There is a bony canal (the ‘aqueduct’) that runs through the skull, connecting the cranial cavity to the inner ear (the ‘vestibule’). And within that canal is a tube called the ‘endolymphatic duct’ which runs through this aqueduct to a collection pouch called the ‘endolymphatic sac’.

This duct contains a fluid called ‘endolymph’ which travels through this duct to the sac – hence the name. This fluid normally passes from the inner ear towards this collection sac.

But if both this duct and sac become enlarged then this forces the endolymph back towards the inner ear where it affects balance and hearing.

How does this cause hearing loss?

No-one is exactly sure how this causes hearing loss but several theories have been put forward which include:

• Endolymphatic fluid may be too concentrated and damages fine hair cells within the inner ear which results in sudden hearing loss.
• A minor head injury causes changes in air pressure within the ear, causes a tear in one of the delicate membranes in the inner ear which permanently damages hearing.

Causes of large vestibular aqueduct syndrome

This is a recently discovered condition so there is much more to learn about the exact causes of it. But experts now believe that this condition actually starts in childhood when the ear structures are still developing which makes them vulnerable to disease or injury.

Other possible causes include damage caused by a head injury, increase in cerebrospinal fluid during exercise or physical exertion or changes in air pressure within the ear. At present the only way of diagnosing this condition is via a CT scan.

The most obvious symptom of large vestibular aqueduct syndrome is that of hearing loss. The extent of this loss will vary between individuals and in some cases there will be complete hearing loss (permanent deafness).

Treatment of large vestibular aqueduct syndrome

As long as there is still partial hearing then there is one form of treatment available which is a hearing aid. Any hearing lost cannot be restored but at the very least this will enable the sufferer to

maintain their current level of hearing and communicate with others. However, regular hearing tests will be needed to check for signs of any further deterioration in hearing.