Vestibular dilation, or dilated vestibular aqueduct, is also called large vestibular aqueduct, enlarged vestibular aqueduct, or widened vestibular aqueduct. It is also referred to as EVA, enlarged vestibular aqueduct. This is a condition that is considered both genetic and environmental.
Even if this duct is enlarged by a mere millimeter, it is still considered abnormally enlarged. The vestibular aqueducts are tiny canals that connect the temporal bone part of the inner ear to the skull. If these aqueducts are enlarged it means that the accompanying endolymphatic duct and sac are probably also enlarged. Also within the temporal bone are the cochlea and the vestibular labyrinth. When these are all normal in size they perform together to provide sound waves and nerve signals that allow for movement and gravity detection along with normal hearing and balance.
The enlarged, or dilated, vestibular aqueduct is related to childhood hearing loss because it can be an indicator of the genetic disorder, Pendred syndrome. In many cases children with vestibular dilation and hearing loss also have Pendred syndrome, which is a leading cause of childhood deafness.
While there is no cure, early hearing loss detection and care may help prevent total deafness. Hearing loss from vestibular dilation can be detected by MRI, magnetic resonance imaging, or CT, computed tomography, of the inner ear. The earlier the detection of vestibular dilation, the better for the child’s chance of some hearing ability.
Sometimes steroid therapy is used to treat a sudden onset of hearing loss in children. Other ways to manage the loss of hearing include sign language, hearing aids, or cochlear implants.
If you notice a possible hearing loss or have concerns about your baby or child, contact your family doctor to get started on testing for vestibular dilation and other hearing abnormalities.