Enlarged Vestibular Aqueduct

An enlarged vestibular aqueduct (EVA) is a common inner ear deformity where the bony tunnel that goes from your inner ear to your skull is bigger than normal. These tunnels (vestibular aqueducts) contain structures that hold a sensory fluid called endolymph. Endolymph plays a key role in helping you hear and keeping your balance. When the tunnels are deformed with EVA, this can affect your hearing and balance.

Babies born with EVA often develop hearing loss at some point in their lives. In some cases, children have EVA because they have another genetic disorder or syndrome. The most common is Pendred syndrome. One out of four children with EVA and hearing loss has Pendred syndrome. With Pendred syndrome, hearing loss usually gets worse over time.

There’s no way to predict how EVA will impact your child’s hearing. But seeing a hearing specialist right away is important if you think your child may be having issues. Early treatment can help your child adjust to hearing devices. Having hearing devices helps your child hear speech and sounds around them. It can prevent them from missing out on the learning and social interactions that rely on hearing.

Symptoms of an enlarged vestibular aqueduct

The main symptom is hearing loss. Hearing loss may be in one ear, but it’s usually in both. The degree of hearing loss is usually different in each ear. It often changes without warning and gets worse over time.

Signs of hearing loss include a child who:

• Doesn’t startle when there is a loud noise
• Doesn’t respond when you say their name
• Doesn’t say their first word by the age of 1
• Starts speaking later than their peers
• Asks you to repeat yourself a lot

Your child may also have balance issues, like trouble walking or coordinating movements. But this is less common. In adults with EVA, balance issues may show up as episodes of vertigo or dizziness.

Enlarged vestibular aqueduct causes

Experts don’t know what causes it, but they do know it’s congenital (present at birth). It may relate to abnormal genes that impact how the inner ear develops. Researchers have found several genes that may play a role. The most common one is SLC26A4. This is the same gene that causes Pendred syndrome.

It’s also unclear why having an enlarged vestibular aqueduct leads to hearing problems. But it’s possible that it impacts the balance of the fluid inside (endolymph). The fluid imbalance may affect hearing within your inner ear. This can cause sensorineural hearing loss (when hearing loss affects the inner ear hearing organ and/or the nerve). Experts also think that, in some cases, the genes that cause EVA can cause hearing loss, too.

Hearing loss triggers in EVA

Although enlarged aqueducts are present at birth, it’s usually not until a trigger event that hearing loss becomes noticeable. Newborns may even pass a hearing screening at birth with EVA present. You may not notice hearing loss in a child with EVA until months or years later, even into adulthood.

Triggers include:

1. Fever
2. Head injury (like bumping heads while playing sports or being in a car accident)
3. Pressure changes in the environment (like inside an airplane)
4. Upper respiratory infection (like a head cold or congestion)

Trigger events can also worsen symptoms in people with EVA who already have hearing loss.

How doctors diagnose this condition

Healthcare providers use imaging tests, like CT scans and MRIs, to identify enlarged vestibular aqueducts. They use what’s called the Cincinnati criteria to diagnose it. The criteria say that a vestibular aqueduct is enlarged if it’s greater than or equal to 1 to 2 millimeters. This is about the size of the head of a pin.

Your child will also need hearing tests to determine the extent of the hearing loss. They may need balance testing if dizziness or balance is a concern for your child.

If your child’s symptoms make their provider suspect Pendred syndrome, they may recommend a DNA test to check for an abnormal gene.

How is it treated?

To treat hearing loss, your child may need hearing devices, like:

• Hearing aids: Make sounds louder, so your child can hear better
• Cochlear implants: Help the inner ear hear better for more severe hearing loss

Your child’s care team may include an otolaryngologist (ENT) and audiologist. They can offer support to ensure your child feels comfortable using their new device.

Your child’s provider may also advise you on how to prevent triggers that may worsen their hearing loss. For example, your child may need to avoid contact sports or wear a helmet if there’s a risk of injury. They may need to take special precautions if they’re flying in an airplane (because of the pressure changes).

They’ll advise you on what to do.

When should I see my healthcare provider?

Schedule an appointment with your child’s provider if you’re noticing signs of hearing loss. Your child’s ears enable them to receive information that allows them to engage with the world. Barriers to this engagement (like hearing loss) can impact your child’s development. It can make it harder for them to speak, learn and socialize.

The sooner they get treated, the more likely it is that they can live without having to strain to hear or stress over how to communicate.

What can I expect if my child has this condition?

There isn’t a cure for EVA. And there’s no way to predict how extensive your child’s hearing loss may be.

But hearing aids and cochlear implants can be life-changing for most children living with hearing loss related to EVA.

Ask your child’s healthcare provider how you can help manage their condition. They can help you support your child through treatment. They can suggest ways to make using hearing assistive devices a routine part of your child’s life.