Head rotation evoked tinnitus due to superior semicircular canal dehiscence.
BACKGROUND
Superior semicircular canal dehiscence affects the auditory and vestibular systems due to a partial defect in the canal's bony wall. In most cases, sound- and pressure-induced vertigo are present, and are sometimes accompanied by pulse-synchronous tinnitus.


METHODS
We describe a 50-year-old man with superior semicircular canal dehiscence whose only complaints were head rotation induced tinnitus and autophony. Head rotation in the plane of the right semicircular canal with an angular velocity exceeding 600 degrees/second repeatedly induced a 'cricket' sound in the patient's right ear. High resolution temporal bone computed tomography changes, and an elevated umbo velocity, supported the diagnosis of superior semicircular canal dehiscence.


CONCLUSIONS
In addition to pulse-synchronous or continuous tinnitus, head rotation induced tinnitus can be the only presenting symptom of superior semicircular canal dehiscence without vestibular complaints. We suggest that, in our patient, the bony defect of the superior semicircular canal ('third window') might have enhanced the flow of inner ear fluid, possibly producing tinnitus.
Department of Otolaryngology, School of Medicine, Kangwon National University, Chunchon, South Korea.
E-C
EC
Nam
R
R
Lewis
H H
HH
Nakajima
S N
SN
Merchant
R A
RA
Levine
D001844:Bone Conduction / Q000502:physiology; D006257:Head; D006314:Hearing Loss, Conductive / Q000175:diagnosis; D006319:Hearing Loss, Sensorineural / Q000175:diagnosis; D006320:Hearing Tests; D006801:Humans; D007761:Labyrinthine Fluids / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D012399:Rotation / Q000009:adverse effects*; D012665:Semicircular Canals / Q000000981:diagnostic imaging / Q000473:pathology*; D013701:Temporal Bone / Q000000981:diagnostic imaging; D014012:Tinnitus / Q000209:etiology*; D014057:Tomography, X-Ray Computed