Vibration-Induced Nystagmus as an Office Procedure for the Diagnosis of Superior Semicircular Canal Dehiscence

OBJECTIVE:: To describe nystagmus induced by cranial vibration in a case series of 8 patients with superior semicircular canal dehiscence. DESIGN:: Consecutive case series review. SETTING:: Tertiary vestibular center. PATIENTS:: Eight consecutive patients with computed tomographic confirmed superior semicircular canal dehiscence syndrome observed in the last 24 months. PROCEDURE:: Vertex, bilateral mastoid, and bilateral suboccipital cranial vibration were performed using 100 Hz. Vibration for 10 to 15 seconds on patients in the seated position during office evaluation for vestibular complaints. Nystagmus was monitored by infrared video oculography with digital recording. RESULTS:: All patients demonstrated distinct torsional/vertical vibration-induced nystagmus. Maximal recorded slow-phase velocity was 20 degrees/s. This was observed best with suboccipital vibration on the side of the dehiscence. CONCLUSION:: Vibration-induced torsional/vertical nystagmus, observed best with ipsilateral suboccipital cranial vibration in the seated position, seems to be a sensitive screening test in the office setting for the presence of superior semicircular canal dehiscence.