What is Enlarged Vestibular Aqueduct (EVA)?
Mondini first described Enlarged Vestibular Aqueduct (EVA) in 1791. Also known as “Large” Vestibular Aqueduct syndrome” (LVAS), it involves an enlargement of a bony compartment known as the vestibular aqueduct in the inner ear.
Enlarged Vestibular Aqueduct can in some cases cause hearing loss. It can also leave people increasingly vulnerable to inner ear disease, particularly those associated with a head injury.
What are Vestibular Aqueducts?
“Vestibular aqueducts are narrow, bony canals that travel from the inner ear to deep inside the skull.” (Source)
These aqueducts start in our skull, in an area known as the temporal bone. It can be found just above your ear. The temporal bone is also home to other sensory organs that play an important role in how your ears work: the cochlea and the vestibular labyrinth.
Along with the nerves in our ear, these organs help us to hear, and also help us maintain our balance.
Each of our vestibular aqueducts contain a fluid-filled tube called the endolymphatic duct. This connects our inner ear to a balloon-shaped structure called the endolymphatic sac.
“Recent studies indicate that a vestibular aqueduct is abnormally enlarged if it is larger than one millimeter, roughly the size of the head of a pin. This is called an enlarged vestibular aqueduct, or EVA; the condition is also known as a dilated vestibular aqueduct or a large vestibular aqueduct.” (Source)
Why does EVA cause Hearing Loss?
Research has shown a high correlation between people suffering with EVA and hearing loss. Although scientists are not entirely sure of the exact cause, it is believed that pressure changes in the inner ear are to blame.
Scientists have found that up to 15% of children with sensorineural hearing loss have EVA. “However, scientists do not think that EVA causes the hearing loss, but that both are caused by the same underlying defect. EVA can be an important clue pointing to what is actually causing the hearing loss.” (Source)
How is Enlarged Vestibular Aqueduct Diagnosed?
Magnetic resonance imaging (MRI) or computed tomography (CT) scans of the inner ear can help identify EVA. Medical professionals may suggest one or both imaging scans for children with sensorineural hearing loss.
Is Enlarged Vestibular Aqueduct Treatable?
Unfortunately, there is currently no-known treatment for Enlarged Vestibular Aqueduct. However, people with a known diagnosis of EVA can help to reduce their risks of developing hearing loss. Specifically, they should avoid sports or activities that have a higher likelihood of causing a head injury. In addition, head protection should be worn when engaging in sports like bicycle riding or skiing.
In addition, to reduce the risk of hearing loss people with EVA should avoid situations where barotrauma is possible. Barotrauma is the result of extreme and rapid changes in air pressure. Examples of things to avoid would include scuba diving, where pressure changes during descent and ascent can be extreme.
The best way to reduce the impact that EVA can have is to identify hearing loss early. Children who are diagnosed with hearing loss early on have a better chance of developing coping skills to help communication and learning.
Trust the Experts at Regional Hearing and Balance Center
Do you have any more questions? The hearing care professionals at Regional Hearing and Balance Center would be happy to help. Contact us today to request your appointment with our hearing care professionals.