![]() More research on this topic needs to be completed to determine if such treatment is effective. There is some anecdotal evidence that a course of steroids may be helpful at restoring some hearing in the setting of a sudden sensorineural hearing loss in patients with EVA. Managing and Treating EVAĬredit: Photo courtesy of the National Institutes of Health, Department of Health and Human Services.Unfortunately, there are no consistently documented medical or surgical treatments for EVA. Although most imaging studies in this setting are normal, the most common finding on an abnormal CT is EVA. This is perhaps more important in the setting of unilateral or sudden hearing loss and would consist of magnetic resonance imaging (MRI), computed tomography (CT) scanning, or both. Once a sensorineural hearing loss has been confirmed, imaging is often obtained to evaluate the anatomy of the inner ear. Investigation into a suspected hearing loss typically involves confirmatory hearing testing, often with age-appropriate audiometry and, possibly auditory brainstem response (ABR) testing. ![]() Two mutations in the SLC26A4 gene can result in Pendred syndrome and other factors, genetic or environmental, may also lead to EVA. The most well-known cause of EVA and hearing loss is a gene mutation, known as SLC26A4 (previously known as the PDS gene). The exact cause of EVA is unknown but is likely multifactorial. If balance disturbances are more problematic, specific vestibular testing with focused vestibular rehabilitation may be required. Fortunately, the brain is very adept at compensating for such an abnormality so these balance difficulties are typically transient and mild. Given the close anatomic relationship between the hearing and balance centers in the inner ear and their connection to the endolymphatic sac through the vestibular aqueduct, it is no surprise that children with hearing loss associated with EVA may also have problems with their balance. Hearing Loss May Affect Balance Center in the Ear The hearing loss associated with Pendred syndrome is more likely to be progressive, meaning there is a reasonable likelihood the hearing loss may progress and become more severe, perhaps even resulting in deafness. According to a study by the National Institute on Deafness and Other Communication Disorders (NICDC), approximately a quarter of people with EVA and hearing loss have Pendred syndrome. The identification of EVA can be an important clue to understand the actual cause of the hearing loss.ĮVA may be a component of Pendred syndrome which is characterized by hearing loss due to EVA and thyroid disease, among other things. It may not be that the EVA is the cause of the hearing loss but the underlying defect. Children who are diagnosed with sensorineural hearing loss and who go on to have imaging studies as part of their workup will have EVA 5-15 percent of the time. Pendred Syndrome and EVAĬredit: Photo courtesy of the National Institutes of Health, Department of Health and Human Services.Most children with EVA will develop some degree of hearing loss, although the timing and severity of any hearing loss can be variable depending on the patient. The fluids within the endolymphatic duct and sac must remain in careful balance such that any changes, however subtle, may precipitate a hearing loss. ![]() Abnormalities in these structures contribute to sensorineural hearing loss by a mechanism that is not entirely understood. The enlarged vestibular aqueduct (EVA) may be a sign of corresponding enlargement of the endolymphatic duct (which runs through the vestibular aqueduct) and the endolymphatic sac. Definition of EVAĪ vestibular aqueduct that is larger than 1 mm is considered enlarged. Anatomic abnormalities of these structures may contribute to hearing loss, balance disturbances, or both. The cochlea, vestibular organ and nerves that send signals to the brain are responsible for processing sound transmission and contributing to the body’s sense of balance. The inner ear structures consist of separate hearing and balance organs, known as the cochlea and vestibular apparatus, respectively. Structure of the Inner EarĪ vestibular aqueduct is a small, bony canal with the temporal bone of the skull (behind the ear) that connects the inner ear to a nearby balloon-shaped structure called the endolymphatic sac. Information is available through our Health Library or with the following diagrams and more detailed EVA information to give a greater understanding of how EVA occurs and what may trigger EVA. Many unanswered questions remain about the causes, diagnosis, clinical course and treatment of patients with EVA.
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