Superior semicircular canal dehiscence simulating otosclerosis

G. Michael Halmagyi*, Swee T. Aw., Leigh A. McGarvie, Michael J. Todd, Andrew Bradshaw, Robyn A. Yavor, Paul A. Fagan

*Corresponding author for this work

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    Abstract

    This is a report of a patient with an air-bone gap, thought 10 years ago to be a conductive hearing loss due to otosclerosis and treated with a stapedectomy. It now transpires that the patient actually had a conductive hearing gain due to superior semicircular canal dehiscence. In retrospect for as long as he could remember the patient had experienced cochlear hypersensitivity to bone-conducted sounds so that he could hear his own heart beat and joints move, as well as a tuning fork placed at his ankle. He also had vestibular hypersensitivity to air-conducted sounds with sound-induced eye movements (Tullio phenomenon), pressure-induced nystagmus and low-threshold, high-amplitude vestibular-evoked myogenic potentials. Furthermore some of his acoustic reflexes were preserved even after stapedectomy and two revisions. This case shows that if acoustic reflexes are preserved in a patient with an air-bone gap then the patient needs to be checked for sound- and pressure-induced nystagmus and needs to have vestibular-evoked myogenic potential testing. If there is sound- or pressure-induced nystagmus and if the vestibular-evoked myogenic potentials are also preserved, the problem is most likely in the floor of the middle fossa and not in the middle ear, and the patient needs a high-resolution spiral computed tomography (CT) of the temporal bones to show this.

    Original languageEnglish
    Pages (from-to)553-557
    Number of pages5
    JournalJournal of Laryngology and Otology
    Volume117
    Issue number7
    DOIs
    Publication statusPublished - 1 Jul 2003

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    Keywords

    • Bone Conduction
    • Otosclerosis
    • Semicircular Canals
    • Vestibular Function Tests

    Cite this

    Halmagyi, G. M., Aw., S. T., McGarvie, L. A., Todd, M. J., Bradshaw, A., Yavor, R. A., & Fagan, P. A. (2003). Superior semicircular canal dehiscence simulating otosclerosis. Journal of Laryngology and Otology, 117(7), 553-557. https://doi.org/10.1258/002221503322113003