Asymptomatic superior semicircular canal dehiscence

Abstract Objective To describe a case of asymptomatic superior semicircular canal dehiscence. Method Clinical case report. Results A 50-year-old man presenting with right-sided Ménière´s disease also showed an enhanced response on vestibular evoked myogenic potential testing for the left ear. Unilateral left-sided superior semicircular canal bone dehiscence was clearly visualised on a subsequent temporal bone computed tomography scan. These findings were consistent with superior canal dehiscence syndrome. However, the patient did not complain of any specific superior canal dehiscence syndrome symptoms. Given that vestibular evoked myogenic potential testing may detect asymptomatic forms of superior canal dehiscence, as noted in this case, such testing seems to exhibit reduced specificity for superior canal dehiscence syndrome. Conclusion An enhanced response on vestibular evoked myogenic potential testing in isolation appears to be a weaker indicator of superior canal dehiscence syndrome, and rather a marker of superior semicircular canal dehiscence.