Case Study 5

Enlarged Vestibular Aqueduct Treated with Cochlear Implantation

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A 1 year old girl presented to the clinic who was found to have a severe to profound sensorineural hearing loss that was discovered when she was 8 months old. Her observation audiometry results are shown in Audiogram 1. She was fitted with hearing aids for amplification. A high resolution temporal bone CT scan obtained to see if she had an anatomic abnormality (Figure 1). The scan revealed bilateral enlarged vestibular aqueducts (right greater than left). Her hearing loss progressed throughout her childhood. Audiogram 2 (standard audiogram) documented the deterioration of her hearing and her bilateral word recognition score of 40%. A cochlear implant evaluation concluded that she was a good candidate for implantation. At 9 years of age, she underwent a right-sided cochlear implant without complication and her function improved greatly. Audiogram 3 shows her hearing level with the left-sided cochlear implants. Her word recognition score after the cochlear implant on the left was 72%. She now wears a hearing aid on the right and the cochlear implant on the left. It has been 5 years since her cochlear implant and she is currently being evaluated by the cochlear implant team for a left-sided cochlear implant.

The vestibular aqueduct is a connection between the intracranial cavity and inner ear. Enlargement of the vestibular aqueduct is one of the most common inner ear deformities associated with hearing loss during childhood. Patients can present with hearing loss at birth or can present with a progressive hearing loss during childhood or adolescence. Patients may also have vestibular symptoms causing imbalance. When an enlarged vestibular aqueduct is detected in a patient, it is important that the clinician counsel the patient and their family that activities involving increased risk of head trauma or barotrauma are to be avoided (e.g. soccer, football, and rugby as well as playing horn instruments and diving).

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