Abstract
PURPOSE: To describe a treatable form of nystagmus. METHODS: Two patients recently evaluated at the Mayo Clinic had experienced various forms of oscillopsia, imbalance, and worsening symptoms with a Valsalva maneuver. Close inspection of the eye revealed a subtle rotatory nystagmus that was synchronous with the heartbeat. RESULTS: The two patients had surgical treatment for dehiscence of the superior semicircular canal; postoperatively, their symptoms completely resolved. This is a relatively newly discovered condition that has not been described on either slit-lamp or ophthalmoscopic examination. The cause is related to a dehiscence of the superior semicircular canal that permits communication of variable pressures between the intracranial cavity and the perilymphatic spaces of the semicircular canal. CONCLUSION: Being aware of this unusual form of nystagmus may permit physicians to diagnose it--one of the few treatable forms of nystagmus.
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Selected References
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