Bilateral Dehiscence of the Bony Cochlear Basal Turn

Objective To identify bony labyrinth defects as causing symptoms that might otherwise be difficult to understand. Design Imaging investigation on cases of lowered vestibular evoked myogenic potentials (VEMP) threshold. Setting Academic tertiary case-referral medical center. Patients One patient with continuous bilateral tinnitus. Interventions High-resolution computed tomography of petrous bone was performed after audiometry, impedance, and VEMP recording. Results We found a previously unreported dehiscence of the bony plate between the basal turn of the cochlea and the carotid canal. Conclusions A VEMP study could prompt diagnostic imaging tests that might otherwise be neglected. Moreover, it is important to consider the possibility of a bony dehiscence involving not just the semicircular canals.