Enlarged Vestibular Aqueduct (EVA)
These instructions are for Children’s Hospital of Philadelphia (CHOP) patients diagnosed with enlarged vestibular aqueduct.
Important information:
An enlarged vestibular aqueduct (EVA) is a condition caused by a malformation or defect in the narrow bony canal (aqueduct) that runs through the skull connecting the inner ear (vestibule) to the brain. This is present at birth. Inside the vestibular aqueduct is the endolymphatic duct. The endolymphatic duct is a tube that carries endolymph fluid to the endolymphatic sac.
These structures help to make sure that the fluid in the inner ear contains the right amounts of chemicals called ions. Ions help start the nerve signals that send sound and balance information to the brain.
Hearing loss, balance and enlarged vestibular aqueduct
Children with enlarged vestibular aqueduct may develop hearing loss in one or both ears. The hearing loss can range from mild to severe or profound. The problem can be:
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Sensorineural: problem with the inner ear that is usually permanent
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Conductive: problem in the outer or middle ear
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Mixed: problem in the outer or middle ear and the inner ear
The hearing loss may get worse over time, or it may stay the same. Approximately 5 to 15% of children with sensorineural hearing loss also have enlarged vestibular aqueduct.
Children with enlarged vestibular aqueduct are likely to have problems with coordination and balance. The audiologist may recommend testing to evaluate this.
Diagnosing enlarged vestibular aqueduct
The otolaryngologist, an ear nose and throat specialist, will order an MRI (magnetic resonance imaging) or a CT scan. These scans produce pictures of your child’s inner ear. They may also recommend genetic testing.
Patient instructions:
Identifying hearing loss and balance problems as early as possible is the best way to reduce the impact of enlarged vestibular aqueduct.
There is no way to predict if or how a child’s hearing or balance may change over time. This is why close monitoring with an audiologist is recommended. If hearing or balance does get worse, know that there are options to help your child.
A head injury or head trauma may cause inner ear fluid to flow through the vestibular aqueduct, leading to additional hearing loss. Avoid contact sports where moderate to severe blows to the head are likely. If your child participates in contact sports, head injury protection should be emphasized throughout their lifetime. Examples include:
Since it is impossible to predict which children will have worse symptoms after a head injury, parents will need to weigh the risks and make their own decisions about such activities. Similar considerations apply for activities with severe, rapid pressure changes, like skydiving and scuba diving.
It is important to know that minor pressure changes, such as those during air travel, do not appear to be a concern.
Additional resources:
Contact your audiologist with any questions or concerns.
Center for Childhood Communication
1-800-551-5480
For non-urgent issues, send your audiologist a message in the MyCHOP portal.
Reviewed August 2023 by Danielle Leisner, AuD