3D analysis of cough-induced nystagmus in a patient with superior semicircular canal dehiscence

We report here about a case (female patient) with superior semicircular canal dehiscence (SSCD). This patient presented with pressure-induced rotatory vertigo when she coughed or strained at stool. Loud sounds or Valsalva maneuver did not evoke any sensation of vertigo and/or disequilibrium. By contrast, when she coughed, vertical-rotatory nystagmus was clearly induced. The 3D analysis of cough-induced nystagmus revealed that the rotation axes of the nystagmus were well aligned with the right superior semicircular canal. In conjunction with the temporal bone CT study, the pathological localization in the inner ear in this patient was confirmed to be in the right superior semicircular canal.