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Enlarged Vestibular Aqueduct (EVA)

What Is An Enlarged Vestibular Aqueduct?

An enlarged vestibular aqueduct, or EVA, is an inner ear difference that is present at birth. A vestibular aqueduct is a tiny, bony tunnel inside the skull. With EVA, this tunnel is wider than usual. EVA is often linked to hearing loss. Hearing loss may be present at birth, or it may begin later. It may stay the same, change from day to day, or get worse over time. Some people also have dizziness or balance problems.

What is Happening in My Body?

Each inner ear has a vestibular aqueduct. Think of it as a tiny tunnel that holds a fluid-filled tube called the endolymphatic duct. This tube connects to the endolymphatic sac. These parts may help keep the right balance of fluid and chemicals inside the inner ear. These fluids are important for hearing and balance. When the aqueduct is enlarged, the duct and sac are often enlarged too.

Researchers do not fully understand why EVA and hearing loss happen together. EVA may be a sign of another change that affects how the inner ear works.

Because of this, you or your child may have:

  • Hearing loss in one or both ears
  • Hearing that changes or gets worse over time
  • A sudden drop in hearing
  • Delayed speech or language
  • Trouble responding to sounds or a person’s name
  • Dizziness, vertigo, or unsteadiness
  • Trouble with balance or coordination

Hearing loss usually affects both ears, but one ear may be worse than the other. Balance problems are less common.

It is important to know:

  • EVA is present at birth.
  • A baby with EVA may pass the newborn hearing test.
  • Hearing loss may not appear until months or years later.
  • Most children with EVA develop some amount of hearing loss.
  • EVA is the most common inner ear difference found on scans of children with inner ear hearing loss.
  • EVA may be linked to changes in certain genes such as SLC26A4.
    • Changes in this gene may also cause Pendred syndrome, which can affect hearing and the thyroid gland.
  • Many people with EVA do not have balance problems.

Some people have noticed a drop in hearing after an illness, head injury, or major pressure change. However, research has not proven that avoiding all sports or heavy activity will prevent hearing loss. Ask your provider about helmets, contact sports, flying, scuba diving, and other activities that may involve head injury or large pressure changes.

How is EVA Diagnosed?

  • Hearing tests: An audiogram measures hearing. Babies and young children may have an auditory brainstem response, or ABR, test.
  • CT or MRI scans: These scans show the bones and other parts of the inner ear.
  • Balance testing: This may be done if there is dizziness, delayed walking, or poor balance.
  • Genetic testing: This may look for gene changes linked to EVA or Pendred syndrome.
  • Thyroid testing: This may be needed if Pendred syndrome is suspected.
Newborn undergoing automated auditory brainstem response (AABR) testing.

Parents May Be Asked:

  • Does your child respond to sounds or their name?
  • When did your child say their first words?
  • Has your child’s hearing changed?
  • Does your child fall often or have trouble walking?
  • Is there a family history of hearing loss?

These questions provide helpful clues, but hearing tests and scans are needed to diagnose EVA.

How is EVA Treated?

There is no treatment that can make the vestibular aqueduct smaller. There is also no proven treatment that can stop EVA- related hearing loss from getting worse.

Treatment is based on each person’s needs. It may include:

  • Regular hearing tests
  • Hearing aids
  • A cochlear implant for severe hearing loss when hearing aids do not provide enough help
  • Speech and language therapy
  • Early education and communication support
  • Balance therapy when dizziness or unsteadiness is present
  • Genetic counseling
  • Care from an ENT and an audiologist

Early hearing support is important because children learn speech and language by hearing and communicating with people around them.

What Can I Expect Over Time?

Will It Get Better?
The enlarged aqueduct will not go away. Hearing loss may remain stable, change, or get worse. It is difficult to predict what will happen for one person. Hearing aids and cochlear implants do not cure EVA or restore normal hearing. However, they can greatly improve access to speech and other sounds.

How Long Will Treatment Take?
Treatment and follow-up are ongoing. Hearing should be checked regularly because it may change over time. A hearing device may help soon after it is fitted, but it can take time to adjust to it.

Can I Live a Full Life?
Yes. People with EVA can live full and active lives. Early hearing care, communication support, school services, and balance therapy can help a child learn, communicate, and take part in everyday activities.

When Should I Call My Provider?

Contact a healthcare provider right away for:

  • A sudden loss or major drop in hearing
  • New or severe vertigo
  • Rapidly worsening balance
  • Falls caused by dizziness
  • New hearing problems after a head injury
  • Vomiting that makes it hard to drink fluids

Sudden hearing loss should be checked as soon as possible.

When Should I Get Urgent Medical Care?

Call 911 or seek emergency care for:

  • New weakness or numbness, especially on one side
  • Trouble speaking or understanding speech
  • New severe trouble walking
  • Double vision
  • Fainting
  • Chest pain
  • A sudden, severe headache
  • A serious head injury
  • Repeated vomiting with signs of dehydration

These symptoms are not usually caused by EVA and may be signs of another medical problem.

Questions to Ask Your Provider

It may be helpful to ask your provider questions like the ones below to learn more about your symptoms and any possible treatments.

  • Is there hearing loss in one or both ears?
  • What may be causing the hearing loss?
  • How often should hearing be tested?
  • Could the hearing loss get worse?
  • Is genetic testing recommended?
  • Does the thyroid need to be checked?
  • Are hearing aids needed?
  • When should a cochlear implant be considered?
  • Is there a balance problem?
  • Would balance therapy help?
  • Are there any activities that require added safety steps?

Key Points to Remember

  • EVA is a bony inner ear difference that is present at birth.
  • Hearing may be normal at birth and change later.
  • Hearing loss may affect one or both ears and may get worse over time.
  • Dizziness and balance problems can occur but are less common.
  • EVA may be linked to genetic conditions such as Pendred syndrome.
  • There is no cure, but hearing devices and early support can improve hearing and communication.
  • Regular hearing tests are important because hearing may change.

Additional Resources