Pressure testing for superior canal dehiscence syndrome
Valsalva; Superior canal dehiscence syndrome
Tony Brune, DO, Departments of Neurology, The Johns Hopkins School of Medicine; Daniel R. Gold, DO, Departments of Neurology, Ophthalmology, Neurosurgery, Otolaryngology - Head & Neck Surgery, The Johns Hopkins School of Medicine
Superior semicircular canal dehiscence syndrome (SCDS) is caused by a third mobile window in the inner ear. This allows for transmission of sound or pressure to the superior canal. Tragal compression and/or glottic and pinched nose Valsalva may provoke vertigo and vertical-torsional nystagmus in the plane of the superior (anterior) canal. As an example, a patient with right SCDS may have downbeat-torsional (towards right ear) nystagmus provoked by pinched nose Valsalva, which is an excitatory pattern of nystagmus (see video, https://collections.lib.utah.edu/details?id=1213443). Nystagmus and vertigo are also commonly triggered by loud environmental noises, or provoked by loud tones in the clinic.
Spencer S. Eccles Health Sciences Library, University of Utah